I 

The Response of Vegetation to Disturbance in 

Death Valley National Monument, California 

U.S. GEOLOGICAL SURVEY BULLETIN 1793 I 

The Response of Vegetation to Disturbance in 

Death Valley National Monument, California 

By ROBERT H. WEBB, JOHN W. STEIGER, and 

EVELYN B. NEWMAN 

U.S. GEOLOGICAL SURVEY BULLETIN 1793 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1988 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center, Box 25425 

Denver, CO 80225 

library of Congress Cataloging-in-Publication Data 

Webb, Robert H. 

The response of vegetation to disturbance in Death Valley 

National Monument, California. 

U.S. Geological Survey Bulletin 1793 

Bibliography. 

Supt. of Docs. No.: I 19.3:1793 

1. Desert flora-California-Ecology. 2. Desert floraDeath Valley National Monument (Calif. and Nev.) 3. Plant 

succession-California. 4. Plant succession-Death Valley 

National Monument (Calif. and Nev.) 5. Vegetation 

dynamics-California. 6. Vegetation dynamics-Death 

Valley National Monument (Calif. and Nev.) 7. Death Valley 

National Monument (Calif. and Nev.) I. Steiger, john W. II. 

Newman, Evelyn B. Ill. Title. IV. Series. 

QE75.B9 No. 1793 

[QK149] 

581.5'222 87-600491 
CONTENTS 

Abstract 1 

Introduction 2 

Acknowledgments 2 

Human use of the Death Valley area 3 

Soil and vegetation processes important to revegetation 4 

Soil processes 4 

Rates of soil formation in deserts 4 

Processes of soil recovery from compaction 6 

The effects of soil compaction on plant growth 6 

Vegetation processes 6 

Models of plant succession 6 

Succession in deserts 7 

Recovery of desert vegetation 10 

Life-history strategies 11 

The succession model of Grime 12 

Paleoecology of the Death Valley region 12 

Methods 14 

Study-site selection 14 

Soils 14 

Vegetation 15 

Vegetation measurements 15 

Ordination 15 

Reproducibility and spatial variability 16 

Primary plant succession on debris flows in Wood Canyon 17 

The debris flows 17 

The 1976 debris flow 17 

Older debris flows originating in granitic rocks 19 

Debris flows originating in metasedimentary rocks of the Kingston Peak(?) 

Formation 20 

Estimation of the ages of the debris flows 21 

Discussion 23 

Recovery of Skidoo townsite and the Skidoo pipeline 24 

History of Skidoo and the Skidoo pipeline 24 

Methods 26 

Skidoo townsite 26 

The Skidoo pipeline 29 

Results 31 

Recovery at Skidoo townsite 31 

Recovery along the Skidoo pipeline 32 

Discussion 33 

Primary plant succession on alluvial terraces in Gold Valley and recovery of Gold Valley townsite 34 

Methods 36 

Terrace sequences A and B 36 

Terrace sequence C and Gold Valley townsite 37 

Discussion 42 

Recovery of Greenwater, Kunze, and Furnace townsites 43 

History of the Greenwater district 43 

The setting of the townsites 46 

Methods 49 

Study-site selection 49 

Soil and vegetation measurements 50 

Results 50 

Contents Ill 
Contents IV 

Recovery of compacted soils at Greenwater and Furnace townsites 50 

Recovery of vegetation at Greenwater townsite 51 

Recovery of vegetation at Furnace and Kunze townsites 52 

Discussion 52 

Paleoecological studies in the Black Mountains 53 

Methods 53 

Results 53 

Discussion 55 

A model of succession in Death Valley 57 

Definition of succession 57 

Primary succession in Death Valley 57 

Recovery of soil properties and revegetation of abandoned townsites 58 

Ordinations 58 

Comparisons and contrasts between primary and secondary succession 61 

Life-history strategies and succession 63 

The forces behind succession in Death Valley 63 

References cited 64 

FIGURES 

1. Index map showing location of study sites 3 

2. Diagram illustrating the carbonate morphology classification of Gile and others 

(1981) 4 

3. Graphs of the monthly climate for Death Valley National Monument, Calif., 

and Las Cruces, N. Mex. 5 

4. Aerial photograph of Wood Canyon showing recent debris flows 18 

5-8. Photographs of: 

5. Debris flow 1 and adjacent, older flows 19 

6. Snout of debris flow 1 20 

7. Snout of debris flow 3 21 

8. Western Wood Canyon showing Skidoo pipeline corridor and debris flows 

A,B,andC 21 

9. Map and aerial photograph of Skidoo townsite showing the locations of study 

sites 25 

10-14. Photographs of: 

10. Skidoo townsite in 1907, 1960, and 1983, viewed toward the southeast 26 

11. Skidoo townsite in 1916 and 1983, viewed toward the northwest 28 

12. Skidoo pipeline west of Birch Spring, June 1981 29 

13. Skidoo pipeline corridor at Nemo Crest in 1938 during salvage operations, and in June 1981 30 

14. Skidoo pipeline corridor across Wildrose Canyon 31 

15. Graph of penetration resistance vs. depth curves for soils at Skidoo townsite 31 

16. Photographs of cryptogamic crusts at Skidoo townsite 32 

17. Aerial photograph of Gold Valley showing location of study sites 35 

18. Photographs of terrace sequence A in Gold Valley 38 

19. Cross sections of terrace sequences A and Bin Gold Valley 40 

20. Photographs of Gold Valley townsite and terrace sequence C 40 

21. Cross section of terrace sequence C and Gold Valley townsite 42 

22. Graph of penetration resistance vs. depth curves for soils at Gold Valley 

townsite 42 

23-26. Photographs of: 

23. Greenwater townsite in 1906 and 1981 44 

24. Kunze townsite in 1906 and 1983 45 

25. Furnace townsite in 1906 and 1983 46 

26. Locale of Greenwater Times office at Kunze townsite in 1906 and 

1983 47 
27-29. Aerial photographs of: 

27. Greenwater townsite 48 

28. Kunze townsite 49 

29. Furnace townsite 50 

30. Histograms showing the volumes of individual~ tridentata in Greenwater and Furnace townsites 51 

31. Photograph of the fossil packrat midden collection site near Greenwater 

townsite 54 

32. Diagram illustrating the change in concentration of plant macrofossils with 

time in middens collected from the vicinity of Greenwater townsite 55 

33-36. Ordination graphs based on: 

TABLES 

33. Contents of fossil packrat middens using principal-components analysis 

and factor analysis (oblique rotation) 56 

34. Plant cover at townsites in ~-dominated assemblages, showing 

principal-components solution and Wisconsin polar-ordination 

solution 59 

35. Plant density at townsites in ~-dominated assemblages, showing 

principal-components solution and Wisconsin polar ordination 

solution 60 

36. Plant cover at sites in the Panamint Range, showing principalcomponents solution and Wisconsin polar ordination solution 62 

1. Application of the life-history classification framework of Grime (1979) to 

desert species 73 

2. Regression coefficients of dry-weight biomass for Mojave Desert shrubs 74 

3. Density and cover of perennial vegetation as field tested in Gold Valley, showing 

variability by different operators viewing transects fixed by each operator 74 

4. Density and cover of perennial vegetation as field tested in Gold Valley, showing 

variability by different operators viewing the same transect 75 

5. Comparison of vegetation data from Wahmonie townsite and control areas 75 

6. Soil and site descriptions for debris flows in Wood Canyon 76 

7. Density and cover of perennial vegetation on four debris flows originating in 

granitein eastern Wood Canyon 77 

8. Density and cover of perennial vegetation on three debris flows originating in 

the Kingston Peak(?) Formation in western Wood Canyon 78 

9. Carbonate morphologies of soils on debris flows in Wood Canyon 79 

10. Description of soil near the intersection of 4th and Skidoo Streets (fig. 9, site 

B), Skidoo townsite 79 

11. Physical properties of soils in disturbed and undisturbed areas of Skidoo townsite 79 

12. Density and cover of perennial vegetation at Skidoo townsite 80 

13. Calculated dry-weight biomass of abundant woody perennials at Skidoo townsite 81 

14. Cover of cryptogamic crusts in disturbed and undisturbed areas and estimated 

recovery time at Skidoo townsite 81 

15. Cover of perennial vegetation along three segments of the Skidoo pipeline 

corridor at Harrisburg Flats 81 

16. Density and cover of perennial vegetation along the Skidoo pipeline corridor 

in Wood Canyon 82 

17. Calculated dry-weight biomass for abundant woody perennials along three 

segments of the Skidoo pipeline corridor in Wood Canyon 83 

18-20. Cover of perennial vegetation along the Skidoo pipeline corridor and control 

areas: 

18. At Nemo Crest, including a nearby road 84 

19. On a sloping segment north of Nemo Crest 85 

20. At Wildrose Canyon 85 

Contents V 
Contents VI 

21. Description of soils for terrace sequences A and B in Gold Valley 86 

22. Density and cover of perennial vegetation on terrace sequence A in Gold Valley 87 

23. Density and cover of perennial vegetation on terrace sequence Bin Gold Valley 88 

24. Description of soils for terrace sequence C and the Gold Valley townsite 89 

25. Density and cover of perennial vegetation on terrace sequence C in Gold Valley 90 

26. Physical properties of soils in disturbed and undisturbed areas of Gold Valley 

townsite 90 

27. Density and cover of perennial vegetation at Gold Valley townsite 91 

28. Carbonate morphologies for soils on terrace sequences in Gold Valley 91 

29. Description of soils for Greenwater, Furnace, and Kunze townsites and Greenwater controls C and D 92 

30. Penetration depths of disturbed and undisturbed soils in Greenwater and 

Furnace townsites 92 

31. Density and cover of perennial vegetation in disturbed sites A and B and 

control sites C and D at lower Greenwater townsite 93 

32. Density and cover of perennial vegetation in cleared area E and control site F 

at upper Greenwater townsite 93 

33. Calculated dry-weight biomass for abundant woody perennials and the 

perennial grass S1il2a in lower Greenwater townsite 94 

34. Calculated dry-weight biomass for abundant woody perennials and the 

perennial grass S1il2a in upper Greenwater townsite 94 

35. Density and biomass of perennial vegetation on 16 house pads of varying size 

at Greenwater townsite 94 

36. Density and cover of perennial vegetation at Furnace and Kunze townsites and 

at Furnace control 95 

37. Calculated dry-weight biomass for abundant woody perennials and the 

perennial grass S1il2a at Furnace and Kunze townsites and Furnace control 95 

38. Concentration of plant macrofossils found in packrat middens collected near 

Greenwater townsite 96 

39. Plant assemblages occurring on surfaces differentiated by carbonate 

morphology in Death Valley National Monument 97 

40. Summary of estimated recovery times for compacted soils at four townsites 97 

41. Dominant species occurring on surfaces differentiated by degree of disturbance 

for all townsites 98 

42. Dominant species occurring on surfaces differentiated by degree of disturbance 

along segments of the Skidoo pipeline corridor 98 

43-46. Data used for the construction and interpretation of ordination graphs using 

principal-components analysis (figs. 34-36) 

43. Hybrid correlation matrix based on cover and density in townsites 

containing ~ tridentata 99 

44. Amount of variance explained by the first three axes of the principalcomponents solution for sites in ~-dominated assemblages 99 

45. Correlation-coefficient matrix based on cover for sites in the Panamint 

Range 100 

46. Cumulative variance explained by the first three axes of the principalcomponents solution for sites in the Panamint Mountains 101 

47. Perennial vegetation found at all sites 102 
The Response of Vegetation to Disturbance in 

Death Valley National Monument, California 

By Robert H. Webb, John W. Steiger, and Evelyn B. Newman 

Abstract 

The response of desert plant assemblages to disturbance 

was studied in Death Valley National Monument, California. 

Plant assemblages on debris flows, alluvial terraces, five abandoned townsites, and a pipeline corridor were measured to 

quantify recovery rates and to develop a model of change in 

desert vegetation. A review of the literature revealed that little 

was known about the nature and rate of recovery in disturbed 

desert ecosystems. 

Plant succession models are commonly used to describe 

vegetation dynamics that occur after disturbances. Plant 

succession refers to sequential, directional changes in the species 

composition of a plant assemblage that are caused by forces 

internal and (or) external to the assemblage. The nature of these 

forces is controversial and dependent upon which model is used; 

most plant ecologists ascribe them to biological processes. As a 

result, a common mistaken belief is that plant succession does 

not occur in deserts because sequential, directional changes 

have not been consistently observed and measured and the 

influence of biological processes is assumed to be negligible. 

Vegetation assemblages occurring on debris flows of 

different age illustrate sequential, directional changes in the 

species composition of areas in the Panamint Range dominated 

by Coleogyne ramosissima. Debris flows were differentiated in 

age on the basis of the degree of soil development. The species 

composition changed on debris flows of increasing age, as 

indicated by increasing soil development, from species with 

short lifespans oriented to rapid recruitment (for example, 

Lupin us excubitus) to a mixture of species (for example, Ephedra 

nevadensis, Lycium andersonii, and Grayia spinosa) to longlived, maintenance-oriented species (for example, Coleogyne). 

This primary succession sequence, so named because it occurs 

on a newly created surface, requires thousands of years for the 

change in dam in ants from short-lived, reproduction-oriented to 

long-lived, maintenance-oriented species. 

The recovery of vegetation assemblages at the Skidoo 

townsite and in the Skidoo pipeline corridor indicates a pattern 

of vegetation change similar to that measured on the debris flows. 

These disturbed sites, with recovery periods after abandonment 

of between 42 and 74 years, were generally colonized by shortlived, reproduction-oriented species (for example, 

Chrysothamnus viscidiflorus, and perennial grasses) with 

variable colonization by other species (for example, Grayia, 

Ephedra, and Coleogyne). The time required for complete 

recovery of disturbed sites appears to depend on the stage of the 

predisturbance primary succession. Soil compaction, a possible 

inhibitor of vegetation establishment, was estimated to require a 

century for complete amelioration but did not appear to 

substantively affect the course of recovery. 

Vegetation assemblages occurring on alluvial terraces of 

different age illustrate sequential, directional changes in the 

species composition of areas dominated by Larrea tridentata in 

the Black Mountains. Alluvial terraces of increasing age 

indicated a primary succession sequence of initial colonization 

by short-lived, reproduction-oriented species (for example, 

Hymenoclea sa Isola) and subsequent changes to dominance by 

long-lived, maintenance-oriented species (for example, Larrea, 

Ambrosiadumosa). Larrea became established in the early stages 

of this sequence. The soils developed on the alluvial terraces 

indicate that thousands of years are required for these changes. 

Buried soils exhumed by erosion complicated the successional 

sequence, which suggests a strong influence of soil properties on 

vegetative composition. 

The townsites of Greenwater, Furnace, Kunze, and Gold 

Valley, all abandoned for 73 years, had vegetation assemblages 

generally dominated by short-lived, reproduction-oriented 

species (for example, Hymenoclea, Stipa speciosa). Other longer 

lived species (for example, Ephedra, Grayia) also became 

established in varying quantities, but Larrea, the predisturbance 

dominant/codominant, had conspicuously low cover and 

density on these disturbed sites. Soil compaction was estimated 

to require a century for amelioration but did not substantively 

affect vegetation establishment. Ordinations using Wisconsin 

polar ordination and principal-components analysis indicated a 

clear differentiation of species composition between disturbed 

and undisturbed sites. 

A climatic fluctuation to cooler and (or) wetter conditions 

could explain the low density and cover of Larrea in townsites. 

An analysis of eight fossil and five modern packrat (Neotoma sp.) 

middens collected at Larrea's upper elevation limit indicated that 

Coleogyne's lower elevation limit, now coincident with Larrea's 

upper elevation limit, has decreased a minimum of 50 m within 

the last 500 years. This change is in accord with upper treeline 

declines and other evidence of a change to cooler and (or) wetter 

conditions in the Western United States. All four town sites where 

Abstract 
Larrea is of conspicuously lower density and cover in the 

colonizing assemblage were built at the upper elevation limit for 

this species. Because of the climatic change, Larrea may now 

only be able to rarely reproduce at its upper elevation limit, hence 

complicating the course of recovery of the townsites. 

The changes in species composition on naturally disturbed 

or human-disturbed sites in Death Valley indicate that 

succession occurs in desert plant assemblages. Evidence from 

nearly every study site indicated that species compositions 

change with time after disturbances and that the types of species 

involved in all stages of change have similar life-history 

strategies. Plant succession is best defined as sequential, 

directional changes in species composition of a vegetation 

assemblage. This definition obviates the need for explicitly 

linked driving forces behind the succession. The successional 

sequences found in Death Valley apparently require thousands 

of years from colonization to stages dominated by long-lived, 

maintenance-oriented species, and they are affected by climatic 

fluctuations and geomorphic processes. Secondary succession 

occurs in abandoned townsites because the species composition 

of colonizing assemblages mirrors that of the primary succession 

sequences. 

The forces responsible for vegetation dynamics change from 

internally derived (autogenic) to externally derived (allogenic) as 

the succession progresses. Colonizing species alter 

microclimates and soil chemistry, indicating autogenic forces. 

The allogenic force of pedogenesis appears to be responsible for 

species composition changes over long time periods. 

Allogenesis ultimately is the most important force because 

pedogenesis and erosion are responsible for alteration and 

destruction of surfaces and climatic changes can alter the 

viability of species. The life-history strategies of the species that 

form assemblages determine how an assemblage will respond to 

autogenic and allogenic forces. Therefore, definitions of 

recovery of disturbed desert plant assemblages are arbitrary and 

must be linked with ongoing successional processes in ambient, 

undisturbed plant assemblages. 

INTRODUCTION 

Humans have had a substantial effect on desert soils and 

vegetation in Death Valley since explorers and prospectors 

first arrived more than a century ago. As a result, the northern 

Mojave Desert has a legacy of abandoned trails, roads, 

townsites, and utility corridors, which usually can be easily 

identified in the landscape. Human-induced disturbances will 

be perpetuated as the population of the Southwest increases, 

and many of these new disturbance sites, like those in Death 

Valley, will be abandoned and natural processes will return the 

landscape to some semblance of its predisturbance condition. 

The course of this recovery from disturbance is the topic of this 

study. How desert soils and vegetation recover following the 

abandonment of disturbed areas is little known, partially 

because of the paucity of data on natural soil and vegetation 

processes. 

This study presents a model of the response of vegetation 

to disturbance in Death Valley National Monument. The 

model was developed by applying generally recognized, but 

often conflicting, concepts of vegetation and soil processes to 

data from sites with a variety of vegetation types and 

disturbance histories. In the first section of this paper, 

extensive literature reviews are provided to discuss the 

development of these concepts and clarify the confusion often 

associated with their use. In the second section, site-specific 

studies within two floristically distinct areas are treated 

separate I y to magnify the variability inherent in the response of 

vegetation to disturbance. 

The response of vegetation to disturbance in the Panamint 

Range on the west side of Death Valley (fig. 1) is discussed in 

the first three studies. In Wood Canyon, recent debris flows 

were studied to determine the initial recovery from extremely 

severe natural disturbance and were compared to sequentially 

older debris flows nearby to evaluate the effect of soil 

development on the recovery process. Fourteen kilometers to 

the north, the abandoned townsite of Skidoo was used to 

determine the recovery from a less severe disturbance, but one 

that had varying levels of soil compaction. The study of the 

Skidoo pipeline corridor, which traverses the Panamints, 

evaluated the effect of geomorphic surface on the recovery 

process. 

The next two case studies discuss the response of 

vegetation to disturbance at lower elevations in the Black 

Mountains on the east side of Death Valley (fig. 1). Alluvial 

terraces of different age in Gold Valley contribute additional 

information about the effect of soil development and 

geomorphic surface on the recovery process. The nearby 

townsites of Gold Valley, Greenwater, Furnace, and Kunze 

provide further information about recovery from humaninduced disturbance. The final study examines the history of 

vegetation change during the late Holocene through analyses 

of fossil packrat middens, and suggestions are made as to how 

climatic changes might affect the revegetation patterns 

observed in Death Valley. 

A discussion of the general revegetation patterns 

indicated by the suite of studies is presented in the final section. 

The relation between all disturbed and control sites within each 

geographic area are analyzed using statistical and graphical 

analyses. Based on these analyses, a conceptual model is 

developed in which to view patterns of revegetation, or 

"succession." Finally, the forces behind the response of 

vegetation to disturbance arc discussed in the context of the 

proposed model. 

Acknowledgments 

We thank the following individuals for their help during 

this project: Walter Helmick and Jay Quade assisted with soil 

descriptions and interpretation of geomorphic features; Steven 

L. Reneau, V crna A. Yocum, Howard G. Wilshire, and Robert 

K. Mark helped with collection of soil samples and plant 

transect data; Michael N. Machette and Steven Levine 

2 Response of Vegetation to Disturbance, Death Valley National Monument, California 
provided soil carbonate analyses; Kenneth L. Cole analyzed 

the contents of packrat middens and supplied paleoecological 

reference materials; Chen Chang-Du, David P. Adam, W. 

Geoff Spaulding, Robert K. Mark, Leslie D. McFadden, John 

C. Tinsley III, Michael N. Machette, Jennifer W. Harden, 

Janice C. Beatley, Neil E. West, Frank C. Vasek, Tony L. 

Burgess, Raymond M. Turner, and Desiree Stuart-Alexander 

reviewed sections or all of the manuscript. 

() 

<-",<:<

09

° Furnace 

Creek : 

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Human Use of the Death Valley Area 

Humans have inhabited the Death Valley region for many 

thousands of years. Their influence on the arid ecosystem 

accelerated with the arrival of immigrants from Europe and the 

Eastern United States, who usually were more concerned with 

exploitation of mineral resources than permanent settlement. 

As a consequence, some areas were settled and abandoned 

I 

I 

I 

I 

I 

I 

I 

I I 

116° 

I ... 

~----~~~~ST~~-----

AREA OF 

MAP 

EXPLANATION 

............. Skidoo pipeline corridor 

~ Ghost town sites 

o Present town sites 

--Contours in 

5000-ft interval 

Figure 1. Location of study sites in and near Death Valley National Monument, California. 

Introduction 3 
within a short time period and have remained unused since 

abandonment. These disturbed-then-abandoned areas are 

analogous to current disturbances in the Mojave Desert, 

including offroad-vehicle use, mining, and road and 

subdivision construction (Webb and Wilshire, 1979). 

Prehistoric people occupied sites in the Death Valley area 

throughout the Holocene (Hunt, 1975, p. 157-162). 

Apparently no prehistoric occupation caused widespread 

disturbances to soils and vegetation, although some large farm 

sites are still discernible (Greene, 1981, p. 362-398). The first 

historical accounts of the Death Valley area were made in 

1849, and mining began in the early 1860's in eastern Inyo 

County (Greene, 1981, p. 1-2). Prospecting became more 

extensive in the early 1900's with the publication of maps and 

the discovery of gold at Goldfield in southern Nevada. The 

towns of Skidoo, Greenwater, Furnace, Kunze, and Gold 

Valley were founded during this period near promising mine 

sites. Most mining operations (with the exception of Skidoo) 

were unprofitable and the townsites were abandoned within a 

short time. Sporadic rushes occurred in the northern Mojave 

Desert until the Great Depression of 1929. Several mines still 

operate within Death Valley National Monument, which was 

established in 1933 (Greene, 1981; Latschar, 1981). 

Death Valley National Monument, with its extensive 

mining history, is exceptionally well endowed with potential 

sites for the study of recovery from disturbance. Mining 

operations created localized areas of disturbance to vegetation 

and soils that ceased when the mines closed, and further 

disturbance to these sites has been minimized by U.S. National 

Park Service policy and the isolation of the sites. These 

attributes make Death Valley National Monument an ideal 

location for the study of recovery of desert soils and vegetation. 

SOIL AND VEGETATION PROCESSES 

IMPORTANT TO REVEGETATION 

Soil Processes 

Rates of Soil Formation in Deserts 

Soil types and rates of soil formation are important to the 

understanding of the response of vegetation to disturbance in 

arid regions. Most soils in deserts are primarily mineral bodies 

that form in response to weathering and plant and animal 

colonization of geologic deposits. The parameters most 

important to soil formation are climate, parent material, 

vegetation, topography, and time (Jenny, 1941; Birkeland, 

1974). The features of desert soils that are indicative of age 

include desert pavements and varnish, argillic (clay enriched) 

horizons, and calcic (carbonate enriched) horizons (Birkeland, 

1974). 

Pavements form at the surface of desert soils in response 

to deflation and wetting and drying of the surface soil (El vidge 

and Iverson, 1983). The parent material is an important factor, 

because easily weathered rocks will disintegrate before 

pavements can form. Pavements typically are varnished with 

iron-manganese compounds and are underlain by A horizons 

(see below) with vesicular pores. Pavements can form within 

several hundred years on gravelly, cobbly deposits, but varnish 

is believed to require 3,000 to 5,000 yr for a visible coat and 

greater than 10,000 yr for a thick coat (Elvidge and Iverson, 

1983). 

Soil horizons generally form parallel to the ground surface 

in response to the establishment of vegetation and leaching by 

rain water. The A horizon is a zone of leaching and 

accumulation of organic material (Soil Survey Staff, 1975, p. 

160). The B horizon is a zone of accumulation of clay minerals 

translocated from the A horizon, and of alteration of in situ 

minerals by chemical weathering. B horizons that show a 

significant alteration in color are called cambic B horizons, 

whereas B horizons with significant clay accumulations are 

called argillic horizons (Soil Survey Staff, 1975). Carbonate 

dissolved in soil water is precipitated in or below the B horizon, 

forming carbonate-enriched C horizons (nomenclature for 

carbonate horizons appears in fig. 2). Carbonate in the parent 

material slows the translocation of clays (Goss and others, 

1973), and some soils have an argillic horizon overlying the 

carbonate-enriched horizon. Gile and others (1981, table 65, 

p. 163), for example, show that the development ofB horizons 

is slower in calcareous than in noncalcareous parent materials. 

Argillic and carbonate-enriched horizons are the most 

commonly used morphological indicators of the age of soils in 

deserts. Most pedogenic clay and carbonate in desert soils is 

derived primarily from dustfall and subsequent translocation 

despite the presence of carbonate and weatherable minerals in 

the parent material (Gile, 1975; Bachman and Machette, 1977, 

p. 36-38). Carbonate accumulation is a more reliable indicator 

of soil age than clay accumulation because the rate of clay 

accumulation is dependent upon the amount of carbonate in 

STAGE 

II Ill IV 

EXPLANATION 

Stage Description of carbonate content for high-gravel soils 

I Thin, discontinuous pebble coatings 

II Continuous pebble coatings with some interpebble fillings 

Ill lnterpebble space filled but not plugged 

IV Plugged horizon capped by a laminar horizon 

Figure 2. Carbonate morphology classification of Gile and others 

(1981' p. 66-67) 

4 Response of Vegetation to Disturbance, Death Valley National Monument, California 
the soil. The rate of carbonate accumulation in soils is 

dependent on the timing and amount of rainfall, the annual 

fluctuations in temperature and evapotranspiration, soil pH, 

the rate of carbonate influx in dustfall, and stability of the soil 

surface (Arkley, 1963; Bachman and Machette, 1977). 

Considerable data are available for the rate of soil 

formation in the Desert Soil Project area near Las Cruces, New 

Mexico (Gile and Grossman, 1979; Gile and others, 1981). 

Precipitation in the Las Cruces area is 210-250 mm/yr with 

more than half of this amount occurring as summer 

thunderstorms (Gile and others, 1981, p. 19); this seasonal 

rainfall pattern differs from the winter-dominated pattern in 

the Death Valley area (see fig. 3). The mean annual 

temperature in Las Cruces is 16 oc. Soils in the Las Cruces 

area have formed on low- to high-carbonate alluvium with 

low to high gravel and cobble contents. The parent material 

for the alluvium is rhyolite and monzonite for low-carbonate 

deposits and mixtures of limestone, sandstone, and (or) 

igneous rocks for high-carbonate materials. The vegetation is 

160 1\ 160 I 

I ' I ' I ' ' " \ I \ 

120 I \ 120 I \ 

I ' I 

I ' \ 

l \ (f) 

f \ a: (f) 80 I \ 80 w a: f \ fw f \ w f- f \ 

w f \ ~ 

~ I \ _j 

f \ _j 

_j I _j \ ~ 40 "' \ 40 ~ / ., / \ 

\ ~ 

~ \ zz ' ' ' Q 

f- Q 0 0 <( 

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(f) 

e; 160 ~-- u 160 ~ w _,.-" ''\ a: a: r ' f- 0.... I \ 0 

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40 I \ 40 I ' /1 \ 

\ / / ' -·/ ~ ..... 

0 0 

M A M A s 0 N D 

MONTH 

Figure 3. Mean monthly precipitation (dashed lines) and 

potential evapotranspiration (solid lines) for two desert areas. 

Potential evapotranspiration was calculated graphically using 

the Thornwaite method (Palmer and Havens, 1958) and data 

from Kurzius (1981) and Gile and others (1981 ). A, Wildrose 

Canyon, Death Valley National Monument. 8, Las Cruces, New 

Mexico. 

Chihuahuan Desert Larrea tridentata (creosote bush) 

assemblages on the younger deposits. 

The influence of a Chihuahuan Desert Larrea assemblage 

versus the influence of Mojave Desert assemblages on soil 

formation rates is unknown. Both vegetation types are 

currently dominated by woody perennials, although the 

vegetation around Las Cruces prior to the introduction of 

domestic livestock was possibly dominated by perennial 

grasses (Buffington and Herbel, 1965). Vegetation type affects 

both the A-horizon thickness (Birkeland, 1974, p. 198) and the 

soil chemical properties (Charley and West, 1975; GarciaMaya and McKell, 1970). Different species transpire at 

different rates, suggesting a possible influence on carbonate 

accumulation and chemical weathering. However, Evans and 

others (1982, p. 217) measured no appreciable differences in 

transpiration among plant species, including Larrea and 

perennial grasses, and in total evapotranspiration between plots 

with and without plants. Hence, climate as manifested by 

evaporation potential is more important than vegetation in 

influencing soil morphology. 

Gile (1975) and Gile and others (1981, p. 164) state that 

stage I carbonate horizons are a major feature of pedogenesis in 

the Holocene in southern New Mexico with the oldest Holocene 

soils having stage II accumulations of carbonate (see fig. 2 for 

definitions). The influence of parent materials on carbonate 

accumulation is difficult to assess, although Gile and others 

(1981, p. 163) did not consider parent material differences, 

other than the presence of limestone in the alluvium, which is 

important to carbonate accumulation during the Holocene. In 

high-gravel, high-carbonate parent materials near Las Cruces, 

discontinuous pebble coatings appear in 100 to 1,100(?) yr old 

deposits; thin continuous pebble coatings are present in 1,100 

to 2,1 00(?) yr old deposits; and pebble coatings increase in 

thickness in 2,200 to 4,600(?) yr old deposits (table 65 of Gile 

and others, 1981, p. 163). In high-gravel, low-carbonate 

material, this chronology for the development of carbonate 

morphology is the same as for high-carbonate materials, but 

cambic B horizons also appear. Very thin argillic horizons 

appear in 2,200 to 4,600(?) yr old deposits if the horizon is 

underlain by a stage I carbonate horizon. Stage III carbonate 

horizons indicate a soil age in excess of 25,000(?) yr. 

The rate of soil development is poorly understood for 

Mojave Desert soils. In one of the few studies of soil 

geomorphology in the Mojave Desert, Bull (1975) presented a 

chronology of the development of calcic horizons in the lower 

Colorado River region of California and Arizona. The age 

control for this chronology is based on correlation with soils 

near Las Cruces and is speculative. This chronology has since 

been used for assigning ages to the Quarternary deposits of the 

area (Carr and Dickey, 1980; Carr and others, 1980; Dickey and 

others, 1980). The rainfall in the lower Colorado River region 

varies from 65 to 97 mm annually, and the mean annual 

temperature is 21 to 22 °C. Therefore, soils on the lower 

Colorado River would be expected to form more slowly than 

soils in Las Cruces, given the same type of parent material, 

slope, exposure, vegetation, and carbonate dust influx, because 

leaching and vegetation influences would be less. 

Soil and Vegetation Processes Important to Revegetation 5 
For the lower Colorado River area, Bull ( 197 5) reports 

that pebble coatings and varnish are absent in deposits younger 

than about 2,000(?) yr old; thin, discontinuous pebble coatings 

and lightly varnished pavements characterize 2,000 to 

5,000(?) yr old deposits; discontinuous (stage I) to continuous 

(stage II) pebble coatings and darkly varnished pavements 

characterize 5,000 to 13,000(?) yr old deposits; and stage II to 

stage III carbonate appears in 25,000 to 125 ,000(?) yr old 

deposits. 

Processes of Soil Recovery from Compaction 

Soil compaction, an important factor in the recovery of 

vegetation, is caused by forces generated by humans, 

livestock, and vehicles traveling over the soil. Compaction is 

manifested by an increase in soil density and strength and a 

decrease in infiltration rate. Loosening of highly compacted 

soils is generally ascribed to the physical processes of claymineral expansion during wetting-and-drying cycles and 

freeze-thaw heaving, and to biological activity. The rate at 

which a compacted soil loosens depends on the amount of 

smectitic clays in the soil, the depth of water penetration, the 

frequency of wetting-and-drying cycles, and the depth of 

compaction in the soil. In arid areas with winter-dominated 

rainfall, wetting-and-drying cycles are infrequent because the 

soil tends to remain damp during the winter and early spring 

and dry during the rest of the year. The effectiveness of freezethaw loosening is dependent upon the amount of soil water, the 

soil texture (Akram and Kemper, 1979), the depth and rate of 

frost penetration, and the amount and depth of compaction. 

Freeze-thaw loosening would probably be most effective in 

deserts with prolonged, cold winters (for example, the Great 

Basin Desert), which allow frost to penetrate the subsurface. 

Biological activity is very important in loosening 

compacted soils. Plants loosen the soil around their roots, and 

small channels are left after the roots die. Animals burrow in 

soils, loosening compacted zones. The effectiveness of 

biological activity in loosening compacted soil is partially 

dependent on the rate at which vegetation and animals 

reoccupy disturbed sites. 

Many recent studies have discussed the rate of recovery 

from compaction. Webb (1982) showed that subsurface 

compaction remained and lightly compacted soils did not 

significantly loosen after one year in a Mojave Desert loamy 

sand. This pattern also has been observed in more humid 

regions (Orr, 1975; Thorud and Frissell, 1976; Vorhees and 

others, 1978). In addition, poorly drained soils require twice 

as much recovery time than do well-drained soils in the USSR 

(Ivanov, 1976), which illustrates the effectiveness of wettingand-drying cycles. Estimates of the recovery time for 

compacted soils range from about a decade (Thorud and 

Frissell, 1976; Blake and others, 1976; Dickerson, 1976) to a 

half century (Greacen and Sands, 1980). One study (Webb and 

Wilshire, 1979) concluded that compacted soils in a Mojave 

Desert ghost town required about a century for total 

amelioration. 

The Effects of Soil Compaction on Plant Growth 

Many agricultural studies have noted equivocal effects of 

compaction on plant growth. Soil strength appears to be the 

most important property that limits plant growth (Taylor and 

Burnett, 1964). Taylor and Gardner (1963, p. 156) report a 

high negative correlation between penetration of cotton 

seedling taproots and soil penetration resistance in sandy soils. 

Similar results have been measured for other crops 

(Zimmerman and Kardos, 1961). 

Highly compacted soil layers restrict roots to shallow 

depths (Phillips and Kirkham, 1962; Grimes and others, 1972) 

and decrease plant heights and yields (Lowry and others, 

1970). Although Raghaven and others ( 1979b) report that plant 

root densities decrease with increasing soil densities, plant 

yields are optimum in soil with a slightly increased bulk 

density (Raghaven and others, 1979a, p. 72-73). This finding 

suggests that the above-ground portion of the plant may be 

positively affected by low levels of compaction despite the 

shorter and deformed roots caused by this compaction 

(Warnaars and Eavis, 1972). Desert plants are adapted to an 

environment of continual stresses, and therefore the addition of 

soil compaction may not be as important as other 

environmental factors in affecting establishment and growth 

of vegetation. 

Vegetation Processes 

Models of Plant Succession 

The revegetation of disturbed areas is often modeled using 

the controversial concept of plant succession. "Succession" 

refers to sequential and directional changes in, or observed 

sequences of, the species composition of an assemblage of 

vegetation at a particular site through time (Mueller-Dombois 

and Ellenberg, 1974, p. 374; Miles, 1979, p. 13). "Primary 

succession" refers to the colonization and subsequent 

sequential changes in vegetation on newly formed substrates 

or previously bare surfaces, whereas "secondary succession" 

refers to the reestablishment of vegetation on a disturbed site 

(Horn, 1974, p. 25; Miles, 1979, p. 47, 54). The distinction 

between primary and secondary succession is ambiguous if the 

substrate was previously occupied by vegetation (Miles, 1979; 

MacMahon, 1980). 

Succession begins with the establishment of colonizing 

species on denuded or newly created surfaces. The relative 

contribution of these species to the total plant assemblage 

(species composition) changes with time as the colonizing 

species are replaced by other invading species. The rate of 

change in species composition decreases with time from an 

initially rapid turnover to an assemblage that changes little in 

composition with time. The end point in succession is 

commonly termed the "climax community" (Clements, 1916). 

The forces controlling succession in a plant assemblage 

are either externally derived (allogenic) or internally derived 

(autogenic). Tansley (1935, p. 267) suggests that there is 

usually a clear dominance of one type of force over the other 

6 Response of Vegetation to Disturbance, Death Valley National Monument, California 
even though both are present in all successions, whereas 

White (1979, p. 261) suggests that a continuum exists between 

allogenic and autogenic forces. Allogenic succession is 

controlled by factors such as geomorphic processes and 

climatic shifts. Autogenic succession, on the other hand, is 

controlled by the species themselves through direct interaction 

with other species and by their alteration of the 

microenvironment. 

Identification of the relative importance of autogenesis or 

allogenesis in causing succession is extremely difficult (Drury 

and Nisbet, 1973; White, 1979), in part because succession is 

a composite of the interaction of these forces (Whittaker, 197 5, 

p. 171; Ricklefs, 1973, p. 760). Also, the distinction between 

autogenesis and allogenesis is vague if individual species have 

time to alter their life-history strategies in response to the 

successional forces. However, the terms are useful in 

classifying the forces behind succession according to the 

control of geomorphic and climatic processes or the control of 

plant interactions and plant-induced modifications of soils. 

Clements (1916) presented an autogenic model of 

succession that has been widely applied. His model is based on 

the force of reaction by which early successional species 

modify the substrate in a way that relinquishes competitive 

superiority to later successional species. Clementsian 

succession terminates in the establishment of the climax 

community, an assemblage that varies little in composition 

with time. This model has been abandoned by some modem 

ecologists (Pickett, 1976, p. 107), because of Clements' 

overgeneralizations (particularly the holistic and 

supraorganismic community concept) and the deterministic 

nature of the theory (Mcintosh, 1980, p. 18-23). Reaction is 

now considered one of an array of forces responsible for 

successions (MacMahon, 1980, 1981). 

Climax-community models are inseparable from 

succession models (Drury and Nisbet, 1973, p. 332; Miles, 

1979, p. 48), and there is considerable controversy over the 

definition of the climax community. According to MuellerDombois and Ellenberg (1974, p. 404) there are two major 

conceptual difficulties with climax models. The concept of 

stability of composition in time has been applied to spatial 

relationships without careful consideration of spatial controls 

such as lithology and microclimate variability. Also, the 

concept of climax implies indefinite geomorphic, pedogenic, 

and climatic stability, which generally cannot be expected. 

White (1979, p. 372) considered the problem of reconciling 

climax with the dynamic nature of all vegetation assemblages 

and suggested that either the climax community be defined 

explicitly for each case or the term be abandoned in favor of 

less ambiguous concepts. 

Many models of succession have been proposed that are 

either based on or are in response to Clements' ideas. A model 

of community-controlled succession, described in editions of 

popular ecology texts (Odum, 1975; Whittaker, 1975), 

dominated successional thought in the 1960's and 1970's. 

After this model was severely criticized (Drury and Nisbet, 

1973), partly for its emphasis on Clementsian reaction as the 

primary force, other models were proposed that discounted the 

holistic nature of an evolving community that permeated the 

community-controlled model (Mcintosh, 1980, 1981). A lifehistory or adaptive strategy approach to succession is taken in 

papers by Hom (1974), Pickett (1976), and Van Hulst (1978). 

This approach views succession as an individualistic, plantby-plant replacement process in which adaptations to stress, 

including disturbance, and competition are the most important 

controlling factors. In a similar manner, Grime (1979) 

presented a model of succession based on the adaptations of 

individual species to differing intensities of stress and 

disturbance. 

Using a more mechanistic approach to the modeling of 

succession, Connell and Slayter (1977) presented three models 

that could account for most autogenic successions. The 

"facilitation model" occurs on sites in which soil modification 

by colonizing species is beneficial and necessary to the 

establishment of later species (the "reaction" of Clements 

(1916)); the "tolerance model" occurs when soil modification 

by colonizing species is not necessary to the establishment of 

later species; and the "inhibition model" occurs when soil 

modification by colonizing species is deleterious to later 

species. 

Perhaps the most comprehensive approach to succession 

is themodeldescribedbyMacMahon(1980, 1981), which uses 

Clements' original terminology with minor but important 

redefinitions and clarifications. This model incorporates both 

the disturbance and environmental forces behind vegetation 

change and places an important emphasis on the effect of 

"residuals" (the surviving seedbank or soil alterations by the 

predisturbance vegetation). The relative importance of 

allogenic and autogenic mechanisms vary according to these 

factors and the life-history strategies of the species involved. 

For a more complete review of general succession models, see 

Miles (1979), MacMahon (1980), and Mcintosh (1980, 1981). 

Succession in Deserts 

"Study nature, not books." -Louis Agassiz 

The occurrence or nonoccurrence of succession in deserts 

has been debated since researchers first studied desert plant 

ecology. Shreve (1925) was one of the first to describe the 

physiography and plants of the California deserts. He referred 

to the vegetation as being in a "very static condition" and stated 

(p. 102): 

In a consideration of the dynamic aspects of the vegetation 

of a region in which the initial, sequential and final stages of 

a succession are characterized by the same species, and 

often by the same individuals, it is doubtful whether these 

conceptions (i.e. succession), formed in regions with a very 

dissimilar vegetation, are of much real utility. 

The harsh environment, adaptations to high-stress conditions, 

and the simplicity of the flora precluded any succession of the 

type proposed by Clements (1916). 

Soil and Vegetation Processes Important to Revegetation 7 
Muller ( 1940) studied the changes in a Chihuahuan Desert 

vegetation assemblage on clay beds exhibiting various states 

of erosion or deposition. He concluded that Clementsian 

succession did not apply because all invading species were 

members of the original vegetation assemblage, not species 

alien to the assemblage. However, Muller was viewing 

vegetation growing on texturally different substrates (Muller, 

1940, p. 208-209); moreover, he inferred a sequence of erosion 

and deposition without temporal control. 

Shreve (1942, p. 203-204), in a widely quoted passage, 

stated: 

Destruction of the original vegetation results in the 

appearance of seedlings, which not only constitute the first 

stage of succession but include in their number the 

individuals which will ultimately restore directly the original 

vegetation. It may be said that successions do not take place 

in desert vegetation and they cannot, therefore, be 

telescoped. It is at least certain that the succession concept 

would never have been developed in a study of the 

vegetation of arid regions. One of the principal reasons for 

the abeyance of successional phenomena is the almost total 

lack of reaction by the plant on its habitat. The existence of 

a plant in a given spot for many years does nothing to make 

that spot a better habitat for some other plant or some other 

species. Fallen leaves and twigs are blown away, or small 

accumulations of organic matter are washed away, to be 

carried ultimately to the nearest flood plain or playa. Also 

little happens to change the character of the soil or its waterholding capacity. Only in the rich stands of desert 

vegetation is there a local amelioration of conditions due to 

the presence of large and long established perennials. 

Shreve based this conclusion on observations but did not 

provide quantitative evidence to support it. 

Several other researchers have agreed with Muller's and 

Shreve's conclusions. Hunt (1966, p. 54) believed that 

reaction could not be important in the assemblages of widely 

spaced individuals on thefloorofDeath Valley. Pianka(1974, 

p. 249) denied the existence of autogenic succession due to the 

purported non-existence of soils in deserts. Beatley (1976) 

recognized that autogenesis might become more important as 

the amount of precipitation increases along an environmental 

gradient. Her discussion of the substrate control (p.72) is 

similar to that of Shreve (1942): 

At the lower and middle elevations in this region [Mojave 

and Transition Desert], soils are scarcely modified by the 

soil-forming processes; hence the substrates are usually 

not fundamentally different after disturbance than before. 

In the absence of climate change, the only species able to 

occupy the soil after disturbance are still the original 

species, i.e., most native species are the colonizing species 

in the region. 

Rowlands and Adams (1980, p. 174) summarized their support 

of the Shreve-Muller conclusions with respect to the Mojave 

Desert by stating: 

Desert vegetation upon destruction replaces itself directly 

by new seedlings of the same species. Characteristically, 

in deserts, species of the original vegetation continue to 

occupy disturbed sites with population increases in some 

species (i.e. colonizing species) and declines in others. 

But, floristically distinct assemblages, or seral stages, 

between initial and climax communities, which in humid 

regions occur in orderly and predictable sequences, are 

not present. 

Wells (1961) presented an argument supporting the 

occurrence of succession in deserts based on the study of 

revegetation in streets of a Mojave Desert ghost town in 

Nevada. Wells found that the initial colonizers were species 

that are normally found in washes or naturally disturbed 

habitats, and he argued that these species were analogous to 

colonizers in more humid regions (p. 671). Shields and Wells 

(1962) argued for secondary succession in a study of 

revegetation of areas in the Nevada Test Site devastated by 

nuclear explosions. Egler (1962) challenged Wells' (1961) 

conclusions based on the presence of colonizing species in the 

undisturbed assemblage. Egler's argument apparently was 

based on the definition of a Clementsian climax, an issue that 

was peripheral to Wells' data. Webb and Wilshire (1979) 

revisited Wells' (1961) site and concluded that secondary 

succession had occurred; however, the role of individual 

species in the succession was ambiguous. 

Karpiscak (1980) studied the invasion of annuals and 

perennials into abandoned agricultural fields in the Sonoran 

Desert of southern Arizona. He found that the initial colonizers 

were nonnative annuals such as Sal sola iberica, and that these 

annuals were sequentially replaced by other annual and 

perennial species with time. Karpiscak (1980, p. 156) argued 

that Shreve could not have viewed succession because the time 

required for succession to occur is far greater than human 

lifespans, and that few disturbances occurred during the time 

Shreve studied the Sonoran Desert. Furthermore, the alien 

annual species that now dominate the early stages of secondary 

succession were not as abundant at the time of Shreve's 

observations. 

Vasek and others (1975a, p. 12) studied revegetation 

along a pipeline corridor in the southern Mojave Desert and 

invoked an argument for secondary succession similar to 

Wells' (1961): 

We conclude, then, that the species of the mature creosote 

bush scrub community have some capability as 

colonizers, and that the primary colonizing species form a 

small but significant fraction of the mature creosote bush 

scrub community. Thus, a characteristic of the creosote 

bush scrub community is that its species are probably 

adapted in varying degree to continual, but relatively slight 

disturbance. Within this relatively sparse vegetation there 

is always some open ground subject to soil shifting, wind 

and water erosion, and other slight disturbances, and 

stands of creosote scrub occur in a variety of successional 

stages. 

Vasek and others (1975a) combined observations and data to 

formulate this conclusion. Lathrop and Archbold (1980b, p. 

8 Response of Vegetation to Disturbance, Death Valley National Monument, California 
225) agreed with Vasek and others but noted that in some cases 

the colonizers of disturbed sites had the same species 

composition as the undisturbed assemblage. Vasek (1980a, p. 

147), studying secondary succession in an excavation in the 

Mojave Desert, stated that succession in deserts is comparable 

to succession in other climatic regimes. However, the pioneer 

species Vasek found were also members of the undisturbed 

assemblage (p. 139); hence, the succession Vasek reported is 

similar to the revegetation patterns observed by Muller and 

Shreve. 

Vasek and Lund (1980) presented an autogenic model of 

primary plant succession on the margin of a playa in the 

southern Mojave Desert. In their model, halophytes become 

established in mud cracks in the playa and accumulate mounds 

of eolian sediments. Eventually, A triplex torreyi (saltbush) is 

able to colonize these mounds, which are less saline than the 

playa clays. The individual A triplex grows large and in turn 

traps more sediments on its mound. The mounds eventually 

are colonized by the saltbush scrub assemblage surrounding 

the lake. Although the composition of vegetation at a site 

changes predictably with time, the substrate also changes from 

salt-bearing clay to relatively salt-free sand through the 

addition of eolian sediments. 

Vasek (1983, p. 22) combined his ideas with those of 

Whittaker (1975) and Pickett (1976) and described five stages 

of succession especially important in deserts: 

(1) Early stages of succession are characterized by 

communities with colonizing individuals with 

relatively uniform, low stature, and rather short life 

spans. 

(2) The commmunity increases in height, structural 

complexity, stratification, and biomass as the early 

successional species are replaced by later successional 

species and by elements of the mature community. 

(3) Productivity and species diversity increase, as does 

niche complementarity, as the community increasingly 

affects the microclimate and soil development. 

( 4) A shift from producing to maintaining, i.e., a decrease 

in productivity, occurs as late successional species are 

replaced by longer-lived climax species. 

(5) As very long-lived species accumulate biomass, 

productivity stabilizes at maintenance levels, 

intermediate long-lived species gradually decrease in 

population size and extreme stability prevails as 

selection for competitive ability results in dominance 

by one or a very few long-lived species. 

This model states that autogenic processes are important in the 

early stages and that a climax community will be attained. 

Vasek's model is very similar to that proposed by Clements 

and does not account for successions involving little or no 

compositional change. 

MacMahon (1980, p. 30, 32; 1981, p. 27) suggested that 

the conspicuousness of succession among assemblages in 

different climatic regimes may be related to the amount and 

variability of rainfall. Rowlands (1980, p. 105) stated that 

plant succession does occur in arid and semiarid regions, but he 

apparently considered succession as dependent on the species 

composition of the assemblage. Rowlands' model, termed 

"parasuccession" (p. 104), lies conceptually between the 

models of Shreve and Vasek. Zedler (1981, p. 426-429) 

suggested that successional concepts and terminology 

developed for forest ecosystems are inadequate for application 

to desert successions. Single events that would qualify as a 

disturbance in deciduous forests would produce little or no 

compositional change in arid ecosystems; and when there is a 

compositional change in arid ecosystems, it does not seem to 

be part of a predictable, unidirectional successional sequence. 

Much of the preceding controversy stems from which 

definition or model of succession each researcher used. 

Conclusions from many of these studies are based on 

deductions from incomplete observations. In addition, some 

researchers have formulated widely applied succession 

models that are based only on studies of limited geographic 

areas. Some of the controversy involves the importance or lack 

thereof of soils and soil-formation rates. Soils do form in arid 

climates, albeit slowly (see Gile, 1975; Gile and others, 1981). 

Most models of primary succession (Muller, 1940; Shreve, 

1942; Pianka, 1974; Beatley, 1976) have not considered soilformation rates or the local effects of individual shrubs on soil 

chemistry. 

Individual plants alter the chemistry of desert soils 

(Roberts, 1950; Paulsen, 1953; Charley and West, 1975; 

Romney and others, 1980). Wallace and others (1980, p. 217) 

asserted that the division of the desert surface into highly 

productive areas directly under shrub mounds and poorly 

productive areas elsewhere is of the "utmost importance to the 

maintenance of the Mojave Desert type of ecosystem." GarciaMaya and McKell (1970, p. 86-87) concluded a study of soil 

nitrogen in a Mojave Desert wash assemblage with the 

statement: 

Accumulation of plant debris and fine soil adds significantly 

to the soil organic matter in the vicinity of a shrub .... Thus, 

the potential contribution of nitrogen from the shrub when 

it dies, the accumulated litter and organic matter under the 

shrub, and the nitrogen in the surface layer of soil under the 

shrub canopy all create "islands of fertility" in association 

with desert shrubs. 

This study and studies in other arid regions (Batanouny and 

Batanouny, 1968; Sharma, 1973; Sharma and Tongway, 1973; 

Tiedemann and Klemnedson, 1973) demonstrate that desert 

shrubs do significantly affect soils. The greater abundance and 

different species composition of desert annuals under shrubs 

than in intershrub areas (Muller, 1953; Halvorson and Patten, 

1975) further illustrates this effect. Under shrubs, more 

nutrients are available, evaporation is decreased, and 

temperature extremes are reduced (Rickard, 1965; Charley, 

1972; Wallace and others, 1980; West, 1983b). Blackburn 

(1975) found that infiltration rates on Artemisia-dominated 

mounds were three to four times greater than on intershrub 

surfaces in Utah. The importance of shrubs in the 

establishment of saguaros (Cereus giganteus) and other desert 

succulents is well established for the Sonoran Desert (Turner 

Soil and Vegetation Processes Important to Revegetation 9 
and others, 1966; Steenbergh and Lowe, 1976, 1977). 

Mycorrhizae (root fungus) in plant litter is known to help in 

survival of Larrea seedlings in Death Valley (Sheps, 1973). 

Although the importance of this autogenic process has not been 

established in a successional framework, the existence of an 

autogenic component in the dynamics of desert assemblages 

cannot be ignored. 

How much compositional change is required for the 

observed vegetation dynamics to be declared a succession is 

another controversial issue. Are colonizing species always 

members of the undisturbed assemblage (hence no succession; 

Muller, 1940; Shreve, 1942; Beatley, 1976), or are they 

members of different assemblages that invade disturbed sites 

(hence succession; Wells, 1961; Vasek and others, 1975a; 

Vasek, 1980a, 1983)? This argument depends upon which 

model of succession is used and whether the size of the plant 

assemblage is important. Wells (1961) argued for succession 

based on the occurrence of species in upland sites that normally 

inhabit washes. On the other hand, Egler (1962) argued against 

succession because small washes pervade Wells' site, leading 

to integration of wash and upland assemblages. The extreme 

case of whether succession occurs in an assemblage composed 

of two species, as occurs at low elevations in the Mojave 

Desert, depends on whether one defines succession according 

to the Clementsian view (for example, Hunt, 1966) or some 

related model, or whether one defines succession merely as 

changes following disturbances (for example, F.C. Vasek, 

written commun., 1981). 

This review indicates that the concept of desert succession 

is controversial, involves many semantic arguments, and has 

been inadequately documented. Vasek and Lund (1980) 

firmly established an autogenic primary plant succession on 

the margins of a dry lake in the southern Mojave Desert. Dry 

lakes, however, constitute only 1.1 percent of the land surface 

area in the deserts of the Southwestern United States (see 

Cooke and Warren, 1973, p. 53). Since alluvial fans occupy a 

much larger percentage of desert surface area (31 percent), 

studies of vegetation dynamics in assemblages on alluvial-fan 

surfaces might be more useful in developing succession 

models for arid environments. 

Recovery of Desert Vegetation 

Utility corridors in the Mojave Desert have provided 

information on recovery of vegetation following disturbance. 

Although utility corridors are the most often used sites for 

artificial revegetation attempts (Kay, 1979), most of the 

disturbed land nearby is abandoned to recover naturally once 

the pipeline or transmission line is in place. Vasek and others 

(1975a) studied a 12-yr-old pipeline corridor in the southern 

Mojave Desert. They found that revegetation was highly 

variable; in general, the most productive sites showed the most 

recovery, as indicated by the reestablishment of "long -lived" 

perennials. Vasek and others (1975a, p. 10) used a linear 

extrapolation to estimate 30 to 40 yr for restoration at the most 

productive sites, but they further stated that the linear model is 

unrealistic and that "many centuries" is probably a more 

realistic estimate (p. 12). 

Vasek and others ( 197 5b) studied 3 3-yr -old transmissionline corridors in the same regions that showed varying degrees 

of disturbance ranging from "slight" under transmission wires 

to "drastic" under pylons. They found that the contribution by 

Larrea to the total plant cover under the pylons was 12 to 73 

percent lower than its contribution in the undisturbed area (p. 

122-123). The total ground cover, however, was higher under 

the pylons than in the undisturbed area in four of five study 

areas, with a large contribution in cover coming from shortlived species, including Hymenoclea salsola (cheesebush). 

The variability of recovery under the pylons was high 

compared with the less-disturbed areas. Vasek and others 

(1975b, p. 129) concluded that after 33 yr revegetation has 

occurred to the extent that the quality of vegetation, as 

measured with an index of cover contribution by long-lived 

perennials, approaches that of the undisturbed areas. Vasek 

and others also found that vegetation levels under the wires and 

along road edges were slightly enhanced, apparently because 

of water harvesting (Johnson and others, 1975). 

Lathrop and Archbold (1980a) studied revegetation along 

two Mojave Desert aqueducts constructed in 1913 and 1970. 

Using a linear estimate of aboveground biomass calculated 

from total-percentage cover data, they estimated a recovery 

time of about 60 yr for the aqueduct right-of-way. The shrubs 

Chrysothamnus nauseosus and C. paniculatus (rabbitbrush) 

contributed the greatest biomass of shrubs (34-38 percent) in 

the 1913 right-of-way but were insignificant (1.5 percent) in 

the control area; similarly, the biomass contribution of 

Chrysothamnus was 19.5-21.7 percent along the 1970 

aqueduct compared with 0.9 percent in the control area), 

although Hymenoclea contributed the greatest biomass (25.1-

30.6 percent; table 2 of Lathrop and Archbold, 1980a., p. 142). 

They concluded that the vegetation along the 1913 aqueduct, 

while virtually recovered with respect to total cover, biomass, 

and cover contributed by "long-lived" species, is "subclimax 

vegetation" (p. 146-147). 

Lathrop and Archbold (1980b) studied numerous utility 

corridors throughout the southern Mojave Desert. They 

concluded that the predictability of recovery times is difficult 

and dependent on the degree of disturbance; the site 

productivity characteristics, including soil quality, climate, 

and species composition of the undisturbed vegetation; the 

proximity and relative lifespan for colonizing species; and the 

variability of vegetation, soil, and intensity of disturbance 

within the area (p. 224). Using a linear model to estimate 

biomass (p. 224), Lathrop and Archbold (1980b, p. 225) 

predicted a recovery time of a century. Lathrop and Archbold 

(1980a, b) stated that an estimate of recovery based on 

vegetative composition could be "at least three times greater" 

than the estimate based on biomass, assuming that recovery 

follows a linear trend. 

Webb and Wilshire (1979) studied the recovery of desert 

vegetation in the Mojave Desert ghost town of Wahmonie, 

Nevada (fig. 1). The species composition of vegetation in the 

townsite (abandoned 51 yr), dominated by Hymenoclea and 

10 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Stipa speciosa (needlegrass), was different from that of the 

surrounding vegetation, which was dominated by Larrea. The 

recovery time of soil compaction was estimated to be a century 

(p. 296), and a comparison of compacted versus noncompacted 

sites indicated a strong influence of compaction on 

revegetation (p. 298). The recovery time for total plant cover 

was estimated to be 40 yr (p. 300). The data from this study are 

compared with those from ghost towns in Death Valley 

National Monument in a later section. 

Life-History Strategies 

Estimates of recovery depend, in part, on the analyses 

used to describe an assemblage. Most recovery studies 

indicate that nonspecific population parameters, such as total 

plant cover, are reestablished much sooner than specific 

parameters, such as species composition. Vasek and others 

(1975a, b) developed an index based on the longevity of 

individual species to take into account both the quantitative 

and qualitative parameters of a given assemblage. To calculate 

this index, however, it is necessary to categorize perennials 

into longevity classes on the basis of "size or long-tenn 

observation" (Vasek and others, 1975a, p. 3). Data on the 

longevity of Mojave Desert species are very scarce, and recent 

studies rN est and others, 1979) have questioned the 

importance of longevity in assemblage stability. Longevity is 

an important aspect of stability, but it should be considered 

together with other species attributes that affect plant 

assemblages. 

In order to compare the rate and mechanics of recovery 

among different assemblages, it is necessary to compare the 

attributes of each species that affect the revegetation pattern. 

Life-history strategies are categories into which species can be 

classified according to these attributes. In reality, life-history 

strategies are as numerous as the species themselves, wherein 

each strategy is a set of attributes that has evolved in response 

to a fluctuating environment and interaction with other species. 

However, a basis of comparison is needed in order to contrast 

revegetation across different assemblages, and the use of 

strategy classification appears to be the most appropriate. 

Grime (1979, p.7) presented three primary strategy 

classifications for all plants: (1) competitors, which exploit 

conditions of low environmental stress and low external 

disturbance; (2) stress tolerators, which are adapted to 

conditions of high environmental stress and low disturbance; 

and (3) ruderals, which are adapted to conditions oflow stress 

yet high disturbance. These strategies have been reconciled 

with the more familiar r- and K-selection strategies of 

MacArthur and Wilson (1967; Grime, 1979, p. 52). 

The three strategies are end points in a continuum of 

possible strategies. Grime (1979, p. 56) also described 

secondary strategy classifications within this continuum. Two 

are important for this discussion: ( 1) stress-tolerant ruderalsannual and perennial species found in unproductive 

environments with short lifespans, high reproductive capacity, 

and an ability to colonize disturbed sites quickly; and (2) stresstolerant competitors-perennial species found in 

unproductive environments with relatively short to long 

lifespans, low to medium reproductive capacity, and an ability 

to survive without abundant resources. For desert perennials, 

the strategies available appear to be the extremes of stress 

tolerators, stress-tolerant ruderals, and stress-tolerant 

competitors (Grime, 1979, p. 150). Grime (1979, p. 24, 67, 

149) considered most desert perennials as stress-tolerant 

competitors, with some categorized as stress tolerators. His 

framework for grouping plants according to life-history 

strategy appears in table 1. 

The use of Grime's classification scheme as a tool in 

understanding revegetation is limited by its degree of 

generalization. The criteria for classifying a species into a 

particular life-history strategy are numerous and, in many 

instances, either poorly defined or speculative. Rarely will a 

species have all the characteristics of one strategy as defined by 

Grime; in some cases, a species may have characteristics that 

fit a number of strategies. Consequently, the researcher must 

determine which life-history characteristics are important to 

the dynamics under study. This subjectivity can lead to 

circular arguments. For example, classifying a species as long 

lived based on its occurrence in a successional sequence will 

probably lead to the conclusion that long-lived species 

dominate the later stages of succession (for example, Vasek 

and others, 1975a, b; Vasek, 1980a, 1983). 

Furthermore, Grime ( 1979, p. 76) notes that there is a large 

quantity of published evidence for genetic variation within a 

species, and that this variation is sufficient to "enlarge 

substantially the strategic and ecologic range of the species." 

He cites several papers describing a common European grass 

with populations that "differ considerably in life-history." 

Populations of the same species adapted to local conditions 

along an environmental gradient, such as elevation, are often 

tenned "ecotypes," and several researchers have emphasized 

the importance of ecotypes in understanding vegetation 

dynamics in the Mojave and Great Basin Deserts (terms apply 

to plant ecology, not physiography; Wallace and others, 

1980). A population at one end of a species' environmental 

gradient may exhibit a different life-history strategy than a 

population at the other end. 

However, Grime's approach allows a finer resolution for 

classification than does the rand K approach of MacArthur and 

Wilson (1967), and it includes important aspects of adaptive 

strategies not taken into account by the longevity approach of 

Vasek. Thus, Grime's approach provides a more powerful 

analytical tool in characterizing revegetation across sites with 

different species composition. However, it is important to 

realize the limitations and weaknesses of Grime's approach 

before application. 

Two aspects of life history not explicitly considered by 

Grime but possibly of importance are the species' carbonreduction pathway and mycorrhizal (root fungus) status. Three 

types of photosynthetic strategy occur in plants: C3 or Calvin 

cycle, C4 or Krantz cycle, and CAM or Crassulacean acid 

metabolism (McNaughton and Wolf, 1979, p. 106-107). The 

C3 pathway is the most common, while CAM species tend to 

be succulents that are adapted to water conservation. C4 

Soil and Vegetation Processes Important to Revegetation 11 
species are intermediate between C3 and CAM species in 

water-use efficiency. 

The ecological significance of these differences is unclear 

(McNaughton and Wolf, 1979). However, because C4 species 

have a better water-use efficiency, higher temperature optima 

for photosynthesis, and tend to be "weeds" in deserts 

(Syvertsen and others, 1976, p. 312), they could possibly 

compete better than C3 species in the more stressful conditions 

inherent in the early stages of succession. Therefore, the C4 

pathwaymaybeanattributeofruderal species. Johnson (1976, 

p. 146) reported that 85 percent of the flowering plants in the 

California deserts are C3 species, while 11 percent are C4 

species and 4 percent are CAM species. Although this figure 

is preliminary, it does suggest that the C4 species are relatively 

unimportant in the Mojave Desert (Johnson, 1976, p. 152). 

Reeves and others (1979) suggested that the lack of 

endomycorrhizae in roots may characterize species that 

behave as ruderals. Reeves and others found that 99 percent of 

individuals in an undisturbed Artemisia tridentata assemblage 

in Colorado were endomycorrhizal, whereas only 1 percent of 

the individuals colonizing a disturbed road were 

endomycorrhizal. Endomycorrhizae benefit the host plant by 

increasing its ability to absorb phosphorus, nitrogen, and other 

elements (Clay, 1981), by increasing its growth rate (Moorman 

and Reeves, 1979), and possibly by increasing its waterabsorption ability. Sheps (1973) found that addition of 

"fungal-infected desert litter" improved survival and growth 

of Larrea seedlings in Death Valley. Endom ycorrhizal 

infections increased the ability of Chrysothamnus nauseosus 

to colonize mine spoils in New Mexico (Lindsey and others, 

1977). The percentage of mycorrhizal species was greater in 

disturbed than undisturbed semiarid areas in southern Arizona 

(Clay, 1981). Wallace and Romney (1972, p. 277-278) found 

abundant mycorrhizal fungi associated with the roots of most 

common Mojave Desert species; this finding suggests that 

mycorrhizal status is not a distinguishing characteristic of lifehistory strategies in the Mojave Desert. 

The paucity of data on Mojave Desert perennials prevents 

a quantitative assessment of life-history strategy, as presented 

by Grime (1979, fig. 18, p. 73). However, some species can be 

tentatively classified under Grime's framework based on the 

characteristics of the life-history strategies (Grime, 1979, p. 

48-49; table 1). Larrea is an archetypal stress tolerator on the 

basis of its longevity (Vasek, 1980b), evergreen leaves, low 

palatability, and ability to flower under any favorable 

conditions (Kay and others, 1977b). HymenocJea sa1so1a and 

Stipa speciosa are probably stress-tolerant ruderals because 

they are perennials with short lifespans and small stature, have 

the ability to quickly colonize disturbed sites, and can produce 

large quantities of seeds (Kay and others, 1977a). Salsola 

iberica is an archetypal ruderal because of its weedy nature, 

high seed production, and ability to colonize disturbed sit~s 

quickly (Shields and Wells, 1962; Rickard and Sauer, 1982; 

Karpiscak and Grosz, 1979; Karpiscak, 1980). Similarly, 

other Mojave Desert species can be tentatively classified 

according to Grime's framework based on published accounts 

(table 1). The rationale for the assignment of life-history 

strategy is based largely on observations of morphology, 

reproductive capacity, and behavior in disturbed sites; data are 

sparse for seed production, demography, or physiology for 

each species. Hence, this classification is tentative and should 

be tested against experimental data. 

The Succession Model of Grime 

Grime (1979) also presented a conceptual model of 

succession to accompany his life-history strategy framework. 

Although his model is based on his classification scheme, its 

verification does not necessarily follow acceptance of his lifehistory framework. However, one of the major criteria for 

Grime's classification scheme is the behavior of a species in a 

disturbed site; consequently, attempts to separate his 

classification framework from his successional model are 

difficult. Based on the premise that life-history strategies 

determine the course of succession, Grime (1979, fig. 42, p. 

151) depicted succession in an unproductive(desert) habitat as 

progressing from ruderals, the initial colonizers of a disturbed 

site, through successive stages of stress-tolerant ruderals, 

stress-tolerant competitors, and stress tolerators. This model 

is simplistic because often species of all four life-history 

strategies are present at any one time, and the effects of 

allogenic processes are ignored. 

Grime's classification framework and his successional 

model are used in this paper for two purposes. The first is to 

characterize succession across different but related 

assemblages. The second is to gain an insight into the use of 

Grime's classification framework and the value of his model in 

depicting succession. Species will be classified for two study 

areas, a primary succession sequence in Wood Canyon and a 

secondary succession sequence in the Greenwater district. 

Paleoecology of the Death Valley Region 

Climatic changes are an important allogenic force behind 

plant succession. Part of the difficulty in interpreting spatially 

distributed vegetation assemblages using the temporal 

framework of succession is the lack of knowledge of late 

Holocene climatic history. Despite many years of 

paleoclimatic study of the Southwest, relatively little is known 

about Holocene climatic fluctuations. It is generally agreed 

that a major climate change occurred at the beginning of the 

Holocene, although the timing and magnitude of the change 

are much debated. 

An informal definition of epochs within the late 

Quaternary is needed for discussion of paleoclimates, 

paleoecology, and the ages of deposits. For the purposes of this 

paper, the Pleistocene-Holocene boundary, normally defined 

as 10,000 yr B.P. (Sohl and Wright, 1980; Palmer, 1983), is 

considered to be 11,000 yr B.P. for consistency with the 

paleoecological record (Van Devender, 1977). The late 

Pleistocene refers to 11,000 to 70,000 yr B.P. and the latest 

12 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Pleistocene refers to 11,000 to 22,000 yr B.P. The Holocene 

is divided into early, middle and late intervals in accordance 

with the paleoecological record (VanDevender, 1977) with 

ages of 8,000 to 11,000 yr B.P., 4,000 to 8,000 yr B.P., and 0 

to 4,000 yr B.P., respectively. 

Paleoecological records show that some plant 

assemblages of the latest Pleistocene were similar to those now 

found 500 to 1,000 m higher in elevation, or at more northerly 

latitudes. Convincing evidence for these changes is derived 

from the analysis of fossil packrat middens. Each midden, a 

debris pile left by Neotoma sp., contains plant parts collected 

from the local area, and therefore its age can be determined 

using radiocarbon analysis. The most complete fossil records 

from the vicinity of Death Valley come from the studies of 

Wells and Berger (1967) and Spaulding (1983) at the Nevada 

Test Site in southern Nevada (fig. 1). Their records document 

vegetational changes from 18,000 yr B.P. into the early 

Holocene. 

Most plant species occurred at lower elevations during the 

late Pleistocene than today. At present, limber pine (Pinus 

flexilis) grows above 2,300 min elevation (Beatley, 1976, p. 

68), pifion (£.: monophylla)-juniper (Juniperus osteosnerma) 

assemblages occur above 1,900 m (Beatley, 1976, p. 67), and 

desert shrub assemblages occur below 1,900 m on the Nevada 

Test Site. A packrat midden dated at41 ,300 yr B.P. containing 

fossils of a pifion-juniper assemblage was collected from a site 

now dominated by Larrea near Greenwater townsite (fig. 1; 

Cole and Webb, 1985). The pifion-juniper type of assemblage 

has not been recorded in the latest Pleistocene. Packrat 

middens dating from 18,000 yr B.P. on the Nevada Test Site 

record a P. flexilis and shadscale (Atriplex confertifolia) 

assemblage occurring as low as 1,800 min elevation; a juniperdesert shrub assemblage was present at lower elevations 

(Spaulding, 1981, 1985). At the end of the Pleistocene ( 11,000 

yr B.P.) the juniper-desert shrub assemblage moved upward 

and became limited to elevations above 900 m, although this 

assemblage remained below its modem elevationallimit well 

into the Holocene (VanDevender, 1977, p. 190). 

The now-widespread pifion-juniper assemblage 

reappeared in the early Holocene at elevations down to 1,500 

m. E. monophylla, not recorded in 15,000 to 11,000 yr old 

middens on the Nevada TestS i te (Spaulding, 1981), appears in 

the early Holocene while the evidence ofP. flexilis in the fossil 

record decreases. Extremely xerophytic species such as Larrea 

and Ambrosia dumosa (burrobush) have not been found in 

early Holocene fossil sites as low as 800 m. Although 

assemblages similar to modem Larrea assemblages have been 

recorded as early as 10,000 yr B.P. in the Colorado Desert 

(K.L. Cole, unpub. data), Larrea probably arrived in the Death 

Valley area during the middle Holocene. Spaulding (1980) 

found fossils of Larrea in Eureka Valley, 150 km northwest of 

Death Valley, in middens as old as 3,930 yr, while Larrea was 

absent in several older middens. 

Vegetation assemblages have continued to change 

throughout the Holocene. In the Sheep Range of southern 

Nevada, desert shrub assemblages replaced pifion-juniper 

woodlands by the middle Holocene (Spaulding, 1981, p. 191). 

Small elevational shifts occurred in the distribution of some 

species during the middle and late Holocene. Pifion-juniper 

assemblages occurred as much as 200m below their modem 

limits at about 3,500 yr B.P. At higher elevations, the 

distributions of£:. flexilis and bristlecone pine(£.: longaeva) 

also may have been slightly lower in elevation at about 1,600 

yr B.P. Fossils suggesting modem vegetation assemblages 

were found in middens dated at about 800 yr B.P. (Spaulding, 

1981, p. 194). 

In the Grand Canyon, most modem dominant species 

replaced Pleistocene species by 8,400 yr B.P. (Cole, 1982, p. 

1143; Phillips, 1977). The lower limits of pifion-juniper 

assemblages may have been higher than their present 

distributions in the middle Holocene. These records are 

consistent with the first half of the warm-dry Altithermal 

proposed by Antevs (1955) for the Great Basin Desert. Five 

packrat middens younger than 2,300 yr old contain evidence of 

plant assemblages that are very similar to modem assemblages 

(Cole, 1981). 

Other indicators of paleoclimates are consistent with the 

distribution of vegetation assemblages as indicated by packrat 

middens. Pollen analyses (for example, Mehringer, 1977) are 

generally consistent with the midden record. Changes in 

hydrologic conditions suggest Pleistocene-Holocene changes 

in water balances. Mehringer ( 1977, p. 113) reports that lakes 

began to dry in the early Holocene, and that the present water 

balance was attained by the middle Holocene. Smith (1968) 

reports that Searles Lake, southeast of Death Valley, had dried 

up by 9,000 yr B.P. However, Hunt and Mabey (1966, p. 2) 

report that a 10-m-deep lake was present in Death Valley 

during the middle Holocene, in contrast to the proposed warmdry climate for that time (Antevs, 1955). This lake may have 

formed in the climatic conditions that were conducive to the 

lowering of woodland limits at about 3,500 yr B .P. in the Sheep 

Range (Spaulding, 1981). Based on an analysis of tree-ring 

widths and upper and lower elevationallimits for P .longaeva, 

LaMarche (1973, p. 653-658) concluded that conditions at 

high elevations (2,700 to 3,500 m) were warm and dry during 

the middle Holocene. 

Paleoclimatic interpretations are often complicated 

because vegetation assemblages rarely behave as units during 

climatic fluctuations, but rather as individual species that 

change their distribution. For example, shadscale (Atriplex 

confertifolia), a xeric dominant of Great Basin Desert 

assemblages, occurred 500 m above its present highest 

elevation around 15,000 yr B.P., whereas most other species 

normally associated with shadscale grew at lower elevations 

than at present (VanDevender and Spaulding, 1979, p. 708; 

Spaulding, 1981). Factors such as migration following a 

climatic change (Davis, 1969), vegetational inertia (Smith, 

1965; Gorham, 1957), and the retention of Pleistocene soils 

(Cole, 1981) also determine the arrival times of species at their 

modem distributional limits. Faunal interaction with 

vegetation is another effect that is poorly understood. These 

factors create a lag time between a climatic change and changes 

Soil and Vegetation Processes Important to Revegetation 13 
in vegetation assemblages. The study of modem ecosystems 

usually requires the assumption that modem vegetation is in 

equilibrium with fauna and climate and that no changes will 

occur without a climatic change. The presence of Holocene 

packrat middens several hundred meters from Greenwater and 

Gold Valley townsites (fig. 1) provides some information on 

the variability of vegetation assemblages during the late 

Holocene. 

METHODS 

Soil and vegetation measurements were made on debris 

flows in Wood Canyon; on alluvial terraces in Gold Valley; in 

and adjacent to the abandoned townsites of Greenwater, 

Furnace, Kunze, Gold Valley, and Skidoo; and along the 

corridor of the dismantled Skidoo pipeline (fig. 1 ). Numerous 

methods were used to quantitatively describe desert soils and 

vegetation. Once a townsite or geomorphic feature of interest 

was located, study sites were selected based on the variability 

of soils and vegetation and the history of the site. During the 

fieldwork of this project (May-June 1981; October and 

December 1981; March 1982; April and May 1983), several 

methods were tested to determine their accuracy, precision, 

and sampling properties. 

Study-Site Selection 

Study sites were selected after an initial reconnaissance. 

Criteria for the selection were ( 1) spatially uniform vegetation, 

(2) spatially uniform soil texture and surficial rock cover, (3) 

large enough area to be representative of surrounding 

vegetation and soil, (4) temporal and spatial uniformity of 

disturbances, and (5) the availability of nearby controls 

representing undisturbed conditions. 

Uniformity in geomorphic surface and vegetation usually 

was determined visually. All townsite study areas were on 

alluvial fans with surfaces of approximately the same age and 

texture as the parent material. Aerial photography was used to 

determine the extent of geomorphic surfaces and disturbances 

and to locate possible representative control sites. Large-scale, 

black-and-white aerial photographs were available for 

different years at each study area. All Death Valley National 

Monument sites were photographed in 1948 (U.S. Geological 

Survey, 1:48,000), 1969 (Death Valley National Monument, 

1:36,000), and 1976 (Death Valley National Monument, 

1:26,000). The 1948 aerial photographs for Greenwater 

Valley townsites and Skidoo were enlarged to 1:24,000 scale 

for field mapping of disturbances. 

Soils 

Soils were described according to the taxonomy of the 

Soil Survey Staff (1975, p. 459-4 77). Soil pits were located in 

the approximate center of the geomorphic surface or disturbed 

site under consideration. Soil textures were determined 

analytically using sieves and the hydrometer method (Day, 

1965). Calcium-carbonate content was measured using the 

gravimetric (Allison and Moody, 1965, p. 1386-1387) and the 

Chittick methods (M.N. Machette, written commun., 1982) on 

the <2-mm soil fraction. 

The degree of residual compaction in townsite soils was 

measured and compared with undisturbed soil and soil in 

active roads. This analysis is based on the assumptions that the 

soil in a townsite was compacted to the same degree when the 

townsite was occupied as the soil in the active road was at the 

time of measurement, and that the soil in the control did not 

receive significant use during occupation. We justified the 

latter assumption by choice of control sites away from the 

center of the townsite, and the former assumption by the 

mechanics of compaction. Within the magnitudes of the 

ground pressure applied by feet, hooves, or wheels, soil density 

should increase logarithmically with increasing application of 

surface pressure to a maximum density (Webb, 1983). Soil 

compacts more easily when wet than when dry (Webb, 1983), 

and all townsites were occupied during winter months. Given 

the duration of occupation (9 months to 11 years), trampling 

most likely would have been ubiquitous and the soil compacted 

to a uniformly high level. 

Sites for soil measurement were selected nonrandomly to 

obtain a representative sample of the soil properties. Sample 

points were always located in intershrub areas; this introduces 

the bias of probable higher compaction. The sample points 

were also distributed around the study site to average the soil 

properties measured. All measurements were considered 

indices of compaction, not absolute measures of the soil 

properties. 

The soil properties measured were penetration depth, 

penetration resistance, shear strength, bulk density, and 

moisture content. Penetration depth was regarded as the depth 

to which a cone, 920 mm2 in area with a 30° nose angle, could 

be pushed into the soil; at least 70 measurements were made at 

each site. Penetration resistance was measured using a 

penetrometer equipped with a cone, 130 mm2 in area with a 30° 

nose angle, that recorded penetration resistance to depths of 30 

em (Carter, 1967); at least 20 measurements were made at each 

site. Soil shear strength was measured using the Cohron1 

sheargraph (Karafiath and Nowatzki, 1978, p. 480-481) at 

Gold Valley townsite. Bulk density was measured using a 54-

mm-diameter, thin-walled soil core sampler (Blake, 1965); at 

least ten 137-cm3 samples were taken for each site and oven 

dried to calculate density and moisture content. 

Reproducibility of the penetration-depth test was 

excellent; a remeasurement of a site in Greenwater townsite 

five months after the initial measurement yielded an identical 

mean (9.88 em) with slightly lower standard deviation (1.21 

' Any use of trade names and trademarks is for descriptive purposes only and 

does not constitute endorsement by the U.S. Geological Survey. 

14 Response of Vegetation to Disturbance, Death Valley National Monument, California 
em vs. 1.67 em) for 70 measurements. The penetrometer 

measurements were correlated with other, more fundamental 

indices of soil compaction, including bulk density and 

infiltration rate (Hillel, 1980, p. 344; Webb and Wilshire, 

1979, table 1, p. 295), and can be used to estimate recovery 

from compaction. 

The soil properties measured in the active roads, 

historically disturbed sites, and undisturbed sites were 

compared to determine recovery. A linear model of recovery 

was used at all sites because only three disturbance times could 

be identified, yielding only two degrees of freedom in the 

model. 

Vegetation 

Vegetation Measurements 

Vegetation measurements included density, percent 

cover, and dimensions of individual shrubs. Species 

identification and nomenclature follow Munz (1974; see table 

43). Plant densities were measured using 50-m-long, 2-mwide belt transects, and percent cover was measured using 50-

m -long line intercepts on the margins of the belt transects. Belt 

transects and line intercepts have been found to be the best 

methods for sampling density and cover of desert vegetation 

(Braun, 1974, p. 80). Transects were placed nonrandomly to 

obtain the best representative sample of each study site. Shrub 

dimensions were measured on individuals of abundant woody 

perennials. At least 30 individuals were selected randomly 

using a point-quarter technique (Cottam and Curtis, 1956, p. 

456) with 5-pace spacings within the local transect areas. 

Errors in measurement were estimated to permit 

comparisons and provide an index of reliability for the data. 

Standard errors of the mean values were calculated for the 

density and cover transects in each area. The base reliability 

of the density measurements, assuming an accuracy in count of 

±1 individual per transect, was ±50 individuals/ha for each 

transect; hence, the results for density were rounded to 100 

individuals/ha. The major source of error in the density 

measurements was the problem of definition of an 

"individual"; some species, particularly Ephedra, can develop 

into clumps with significant overlap in foliage. For this study, 

an individual was considered a separate plant from 

surrounding individuals of the same species if it had less than 

50 percent of an overlap. Percent cover was assumed to be 

accurate to one decimal place because intercepted foliage was 

measured to the nearest 5 em in each 50 m of line intercept. 

Density and cover data were not analyzed using statistics 

because these variables were not randomly sampled and 

assumptions concerning the normality of the distributions 

could not be tested. 

Dry-weight biomass was estimated for all species for 

which volume data could be collected. Volumes were 

calculated to estimate biomass, but these volumes contained 

significant errors due to the sampling technique. R. B. Hunter 

(oral commun., 1981) suggested an operator variability of ±20 

percent on volumes of shrubs. This error is small compared 

with errors due to the definition of individual shrubs and to the 

variability in shrub shapes. The biomass was calculated as the 

product of the mean shrub volume (modeled as a right elliptical 

tube), the mean density, and a regression coefficient relating 

volume to biomass. The regression coefficients used were 

derived from species on the Nevada Test Site (R.B. Hunter, 

written commun., 1981; table 2), a close and comparable 

geographic area. Biomass regression coefficients vary with 

geographical area (see table 2), number of samples, operator 

error, season of measurement, and definition of an individual 

shrub; consequently, the reliability of the dry-weight biomass 

figures is questionable, and they cannot be presented without 

some estimation of error. 

A standard error for each biomass calculation was 

calculated as 

SE2 = (V*D*SER)Z + (D*R*SEV)Z + (V*R*SED)Z (1) 

where V and Dare the mean volume and density, respectively; 

SEV and SED are the standard errors of the mean volume and 

density, respectively; and R and SER are the biomass 

regression coefficient and standard deviation, respectively. 

Considering the other variables involved in the biomass 

estimation, the values of SE are probably less than the actual 

error. 

For comparison among sites, biomass values were needed 

for species without measured shrub volumes. In these cases the 

mean shrub volume and standard error were either estimated 

from a sample of less than 30 individuals or assumed to be 

similar to another population measured nearby. This method 

introduced an additional error in the biomass estimation that 

could not be readily quantified, but it was usually small 

because of the low density of the species. 

The cover of cryptogamic crusts was measured at Skidoo 

townsite (fig. 1 ), the only site studied with significant presence 

of crusts. Cryptogamic crusts are composed of nonvascular 

plants such as lichens, mosses, and algae. Forty 0.5 x 0.2 m 

(0.10 m2

} quadrats were distributed randomly in disturbed and 

control sites. Percent cover was estimated visually using the 

six cover classes as described by Daubenmire (1959). No 

attempt was made to differentiate taxonomic classes. Standard 

deviations were calculated for each site and a recovery time 

was estimated using a linear model. 

Ordination 

Ordination is a method of graphically arranging sites 

according to the composition of the vegetation. Ordination 

generates compositional axes, or directions of change of 

assemblage composition, which may reflect the more 

important environmental gradients (Whittaker, 1975) such as 

elevation, exposure, and disturbance. This technique 

summarizes assemblage data by producing a two-dimensional 

graph in which similar sites are clustered together and 

dissimilar sites are spread apart (Gauch, 1982, p. 118). 

Methods 15 
Two of the most well known and widely accepted 

ordination techniques-Wisconsin polar ordination and principal-components analysis-were used. Other techniques 

exist that may be considered superior (see Gauch, 1982, p. 166-

167), but they are not as familiar to most researchers. The 

Wisconsin polar ordination method (Bray and Curtis, 1957) 

was selected based on (1) the familiarity of the technique to 

most plant ecologists, (2) its relative conceptual simplicity, (3) 

its large yield of information with least computational effort, 

and (4) the success of the method in identifying otherwise 

unrecognizable patterns (Whittaker and Gauch, in Whittaker, 

1973). However, this method requires a degree of subjectivity 

in choosing sites as end points of the axes defining the 

ordination graph. 

The similarity index used in' the Wisconsin polar 

ordination method is percentage similarity (PS; Gauch, 1982, 

p. 112). Percentage dissimilarity (PO) was calculated using 

100 percent as the similarity of replicated samples. PS values 

for replicate samples usually are less than 100 percent; Bray 

and Curtis (1957) and Beals (1960) obtained average PO 

values between replications of82 and 85 percent, respectively. 

However, the ordination itself is not significantly affected by 

using 100 percent to calculate PO, because the dissimilarities 

between sites (as illustrated by geometric distances between 

the points on the ordination) are relative (Mueller-Dombois 

and Ellenberg, 1974, p. 279). 

Criteria for end-point selection in the Wisconsin polar 

ordination method included several arbitrary rules developed 

by Bray and Curtis (1957), Swan and Dix (1966), and 

Newsome and Dix (1968) in order to reduce the degree of 

subjectivity. End points were selected based on the greatest 

difference in the PD values of the data set. In addition, each end 

point had to have at least three PS values greater than 50 

percent; this criterion helps avoid the choice of a site that may 

be too unrelated to the majority of sites and thus may dampen 

the spread. In addition, end points for the Y -axis had to lie 

within the mid-50 percent range of the X-axis; this criterion 

also serves to eliminate tight clustering. Several end points 

failed to meet all the criteria but were selected as the best end 

points available. Readers are referred to Mueller-Dombois and 

Ellenberg (1974,p. 277-286)andGauch (1982,p.126-135)for 

a discussion of Wisconsin polar ordination. 

Principal-components analysis generates axes objectively 

by deriving successive orthogonal axes according to the 

maximum variance possible in the data set. This method often 

gives distorted or ecologically meaningless axes, a problem 

that is not as significant with the Wisconsin polar ordination 

method. Consequently, the two methods are complementary 

(see Gauch, 1982,p. 167). Principal-components analysis uses 

correlation coefficients as the similarity index. This ordination 

begins with the same matrix as used in the Wisconsin polar 

ordination method, except that correlation coefficients are 

calculated between all sites instead of the percentage 

similarity. The ordination is developed from the eigenvalues 

of the resultant square matrix of correlation coefficients. The 

analysis was performed on the U.S. Geological Survey Multics 

Computer System using available programs (Miesch, 1982). 

Readers are referred to Gauch ( 1982, p. 135-144) or Sneath and 

Sokal (1973, p. 245-247) for a discussion of the mathematics 

underlying principal-components analysis. 

Reproducibility and Spatial Variability 

Reproducibility of the vegetation data was field tested in 

Gold Valley (fig. 1). Experiments were designed to show (1) 

the variability introduced by different operators viewing the 

same transects, and (2) the variability introduced by different 

operators viewing transects with slightly different placements. 

In the latter case, transects were roughly marked, and each 

operator fixed the transect lines before their respective 

measurements. In the former case, transect lines were fixed, 

and each operator measured exactly the same transect. 

The reproducibility of data for transects in which the 

operators placed the lines before measurement appears in table 

3. Most measurements agree within the presented standard 

error of the mean values given. Percentage-similarity values 

calculated for cover were 89, 93, and 89 percent for operators 

A vs. B, A vs. C, and B vs. C, respectively. PS values for 

density were 88, 89, and 93 percent for A vs. B, A vs. C, and 

B vs. C, respectively. These values indicate a high degree of 

reproducibility. 

The reproducibility of data for transects in which different 

operators measured the same fixed transect appears in table 4. 

Agreement among the operators is better, with PS values for 

cover of 94, 92, and 96 percent and for density of 95, 93, and 

93 percent for A vs. B, A vs. C, and B vs. C, respectively. 

Again, a high degree of reproducibility is indicated, which 

suggests that PS values lower than 80 percent indicate different 

plant assemblages, as commonly suggested (Gauch, 1982). 

Line-intercept data from Greenwater townsite (fig. 1) 

were analyzed to determine spatial variability problems in 

sampling specific patches of vegetation. Twelve and fourteen 

50-m line intercepts were measured in undisturbed and 

disturbed sites, respectively. The mean ±1 standard error for 

66 PS values for the undisturbed site and 91 PS values for the 

disturbed site were 68.7±1.2 percent and 69.4±0.9 percent, 

respectively. ThePS values ranged from 35 to88percentin the 

undisturbed site and 48 to 86 percent in the disturbed site. 

However, the percentage similarity calculated between the 

undisturbed and disturbed sites, based on the mean values of 

cover for each, was 52.5 percent. This suggests that two 

patches of vegetation may be similar if their PS value is greater 

than 70 percent. 

Correlation coefficients were also calculated for the data 

from Greenwater townsite. The mean± 1 standard error for 66 

correlation coefficients for the undisturbed site and 91 

correlation coefficients for the disturbed site were 0.60 ±0.033 

and 0.69±0.017, respectively. However, the mean correlation 

coefficient between 168 paired undisturbed- and disturbed-site 

transects was -0.05±0.15, indicating no correlation. An 

ordination based on the principal-components analysis (not 

16 Response of Vegetation to Disturbance, Death Valley National Monument, California 
shown) depicted the undisturbed- and disturbed-site transects 

as distinctly separate clusters of points. 

The importance of variability due to short-term climatic 

fluctuations with respect to differences in vegetation measured 

between recovering and undisturbed sites is illustrated by 

comparison of two studies (Beatley, 1979, 1980; Webb and 

Wilshire, 1979). The townsite ofWahmonie, Nevada (fig. 1), 

was built in response to a mining boom and was abandoned in 

1928 (Webb and Wilshire, 1979). Beatley (1979, 1980) 

collected line-intercept data from a small section of the 

townsite and a nearby control in 1963 and 1975 to measure the 

fluctuation in cover with fluctuation in climate. In 1979, Webb 

and Wilshire (1979) collected line intercept data from several 

areas (including Beatley' s sites) to examine the revegetation of 

the townsite. Beatley included dead vegetation in her totalcover measurement, which Webb and Wilshire did not, and her 

data suggested that about 12 to 13 percent of the total cover for 

all her sites was contributed by dead vegetation. Also, Beatley 

did not measure perennial grasses, which contributed 

significant cover (up to 7.7 percent) in Webb and Wilshire's 

measurements. Despite these differences, the percentage 

similarity and correlation coefficient for Heatley's 1963 

measurement and Webb and Wilshire's 1979 measurement in 

the same undisturbed site (table 5) are 80 percent and 0.94, 

respectively, which indicates a high degree of reproducibility 

in measurement of desert vegetation by independent 

researchers at different times. Also, the climatically induced 

cover changes over 16 yr (Beatley, 1980) are much less than 

those observed after 51 yr of recovery in Wahmonie townsite. 

These results suggest that comparisons between disturbed and 

undisturbed vegetation assemblages may be obtained reliably 

regardless of the climatically induced status of the vegetation 

(that is, whether it is a good or a bad year for plant growth). 

PRIMARY PLANT SUCCESSION ON DEBRIS 

FLOWS IN WOOD CANYON 

Wood Canyon, located in the Panamint Range near the 

western rim of Death Valley (fig. 1), is infrequently subjected 

to intense storms that result in debris flows. The Wood Canyon 

case study describes the response of vegetation to this natural 

type of disturbance. The creation of a surface by a debris flow 

eliminates the influence of residual biotic effects (MacMahon, 

1980, 1981), and primary plant succession occurs. In Wood 

Canyon, debris flows that occurred at different times are 

mantled with vegetation assemblages of different species 

composition, which suggests that soil development may 

influence revegetation of disturbed sites. The results from 

Wood Canyon are compared in a later section with results from 

Skidoo townsite (fig. 1), where revegetation occurred on a 

different type of disturbance-the abandoned mining -town 

streets. 

Climatic data are sparse in the Panamint Range. The 

weather station nearest to Wood Canyon is at an elevation of 

1,250 min Wildrose Canyon, 10 km south. This station reports 

a mean annual precipitation and temperature of 191 mm and 

14 °C, respectively, based on a 10-yr record (Kurzius, 1981, 

p.l4-17;fig. 3). Huntandothers(1966,p.B7)estimateamean 

annual precipitation of 250 to 350 mm for the crest of the 

Panamints. Hence, we estimate the mean annual precipitation 

at Wood Canyon to be between 200 and 250 mm. Wood 

Canyon ranges in elevation from 1,585 mat its mouth to 2,350 

m on the south rim; hence, its mean annual temperature may be 

several degrees cooler than the 600-m-lower Wildrose Canyon 

weather station. 

Bedrock on the north and south slopes of the canyon 

consists of quartzites and metaconglomerates of the 

Proterozoic Kingston Peak(?) Formation. Bedrock of the 

eastern reaches of Wood Canyon consists of the Tertiary 

granite north of the main wash, and Late Proterozoic 

Noonday(?) Dolomite, and Kingston Peak(?) Formation (after 

Hunt and Mabey, 1966, plate I) to the east and south of the main 

wash. Alluvium in the eastern section of the canyon also 

contains clasts of limestones, schists, and calcareous 

sandstones. In addition, the granite is capped with a limestone 

unit. 

The vegetation in Wood Canyon can be characterized as 

Transition Desert Coleogyne assemblages and Great Basin 

desert Artemisia and Artemisia-Pinus-Juniper assemblages 

(Beatley, 1976, p. 41-68). The Coleogyne assemblage 

occupies the entire valley below 1,830 m elevation, and it can 

be found even higher on most of the south-facing slopes. The 

Artemisia-Pinus-Juniper assemblage begins at 1,800 to 2,000 

m on steep north-facing slopes and at 2,320 m on south-facing 

slopes to the south of Wood Canyon. It is separated from the 

Coleogyne assemblage on north-facing slopes by an Artemisia 

assemblage. 

The Coleogyne assemblage in Wood Canyon is a mosaic 

of vegetation patches with different dominant species. 

Coleogyne ramosissima (blackbrush) dominates most 

patches, sometimes to the exclusion of other perennials. 

However, there are discrete patches where Lycium andersonii 

(Anderson's thombush), Grayia spinosa (spiny hopsage), and 

Ephedra nevadensis (Mormon tea) assume dominance. 

Lycium, Grayia, and Ephedra also occur in the Coleogynedominated patches but vary in proportion to each other and to 

Coleogyne on different surfaces of the alluvial fans. The 

boundaries between these patches are sharp rather than 

gradational and appear to be related to differences in the ages 

of surfaces on the fan. The plant species found in the study sites 

at Wood Canyon are listed in table 4 7. 

The Debris Flows 

The 1976 Debris Flow 

In early February 1976, heavy rainstorms caused flooding 

and debris flows in the Panamint Range. Total daily rainfall 

amounts on February 6th to lOth at Wildrose Canyon Ranger 

Station were 5, 10, 9, 28, and 2 mm, respectively. Roads in 

Wildrose Canyon were closed because of flooding, and the 

Primary Plant Succession on Debris Flows in Wood Canyon 17 
road from Wildrose Canyon to Furnace Creek was washed out 

at Emigrant Canyon (Pete Sanchez, oral commun., 1981). The 

National Park Service took aerial photographs of the entire 

Death Valley National Monument area during March 1976 and 

preserved an invaluable record of this event. Intense rainfall 

apparently fell on the crest of the Panamints between 

Telescope Peak and Harrisburg Flats, because all the canyons 

to the west of the crest in this area contain debris-flow deposits 

and scoured channels. The greatest flood damage and largest 

debris flows occurred in Wood Canyon and two canyons 

directly to the north. 

Wood Canyon contains a vivid record of the 1976 debris 

flows (fig. 4) superimposed on older debris flows. Large flows 

extend from the eastern margins of the canyon, with no new 

flows originating from the north or south sides of the canyon. 

Two very large flows originated in the Kingston Peak(?) 

Formation and Noonday(?) Dolomite on the southeast side of 

the canyon, while two fairly large and several small flows 

originated in granite to the east (fig. 5). Flooding concurrent 

with the debris flows scoured the vegetation from the main 

drainage (fig. 4), which appeared to have significant 

vegetation cover in both 1948 and 1969 aerial photographs. 

Neither the 1948 nor 1969 aerial photographs showed 

evidence of fresh debris flows, which indicates that debris 

flows occur infrequently in this canyon. 

The northernmost large flow originating in granite, debris 

flow 1 on figure 5, was examined in detail for surficial and 

internal morphology. This flow (fig. 6) has features typical of 

other debris flows (Johnson, 1970, fig.12.2,p.435; Bull, 1977, 

p. 236-239; Costa and Jarrett, 1981, p. 321), including 

prominent lateral deposits on levees near the fan apex, a poorly 

sorted matrix ranging from cobbles to fine sand, and snouts 

composed almost entirely of boulders, cobbles, and gravel 

(figs. 4-6). At least three waves of deposition are apparent in 

the aerial photograph, and additional small lobate deposits can 

be observed in the flows. 

A study site was selected on the terminal deposit where 

debris flow 1 bifurcated into arms on an go to 1 oo slope. The 

texture of the deposit is poorly sorted, cobbly, gravelly, loamy 

sand to sandy loam with no apparent bedding (table 6). The 

terminal deposit appeared to be 1 to 1.5 m thick, and the surface 

was very rough with large cobbles protruding through a sandy 

matrix. Cobbles on the surface and in the profile showed little 

weathering. During deposition, all vegetation in the path of the 

flow was destroyed, and plants at the margins of the flow were 

partially buried in debris. A sheet of sand, 1 to 5 em thick and 

coincident with the debris flow, extended from the margins of 

the arms 1 to 10m onto adjacent deposits. 

Vegetation had appeared on the 1976 debris flow by the 

time of our measurements in June 1981. The most ubiquitous 

Figure 4. Aerial photograph of Wood Canyon showing recent debris flows. Flows A, B, and C originated in the Proterozoic Kingston 

Peak(?) Formation and flows 1, 2, 3, and 4 originated in the Tertiary granite. Photographed March 1976 (National Park Service, 

photograph number DEVA 19-30). 

18 Response of Vegetation to Disturbance, Death Valley National Monument, California 
colonizer was Erodium cicutarium, an annual that formed 

dense stands on some parts of the flow surface. Erodium 

appeared to be generally responsible for the presence of an 

organic-enriched A horizon in the soil. Another annual, 

Bromus rubens, was present on the flow but not to the extent 

of the Erodium. Few other annuals were observed. Annuals 

were not measured because of extreme spatial and temporal 

variability. 

The perennial species present on the 5-yr -old deposit were 

generally not found in the adjacent vegetation (tables 7, 4 7). 

The obvious clumping (figs. 5, 7) of colonizing perennials 

made vegetation measurements difficult to interpret; however, 

Lupinus excubitus was the dominant species on the arms of 

debris flow 1. Above these arms, Chrysothamnus nauseosus 

formed a large clump (visible in the middle distance in fig. 6), 

and on flows to the south, very large Atriplex canescens 

individuals dominated the colonizing assemblage. In general, 

individuals growing on the 1976 debris flows were very large 

and much more vigorous than the individuals of the 

surrounding vegetation. In addition, growth of plants on the 

margins of the flows was also enhanced, probably as a result of 

increased supply of water from the barren surfaces. Thirty-one 

species of perennials were found on the 1976 debris flows, 

thirteen of which were not found in the vegetation on adjacent 

deposits (see table 4 7). 

Figure 5. Debris flow 1 and adjacent, older flows 2 and 3 

originating in the Tertiary granite in eastern Wood Canyon. View 

is toward the west. Photographed December 1981 . 

Debris flow 1 is representative of older debris flows in 

Wood Canyon. Adjacent, older deposits have surface 

morphologies and subsurface structures similar to those in the 

1976 flows (fig. 7), and thus debris flow 1 can be used to 

represent the initial state of these adjacent and older deposits. 

Older Debris Flows Originating in Granitic Rocks 

Examination of deposits near the 1976 debris flows 

indicated that debris-flow deposits are the most common 

valley fill exposed inWood Canyon. A stratigraphic profile in 

the main drainage shows a series of depositional events from 

the same source area (fig. 4; table 6). Textural variations 

suggest that at least four debris-flow deposits are represented 

in the upper 143 em of this section. These deposits, each 27 to 

45 em thick, have the pedogenic features of stage I to stage II 

carbonate horizons (table 6; see fig. 2 for nomenclature on 

carbonate stages). Cambic or argillic B horizons are not 

present, probably because the soils are young (Gile and others, 

1981). A buried soil below 143 em is characterized by an 

argillic horizon and a stage IV carbonate horizon, suggesting 

a long hiatus in deposition that probably occurred during the 

late Pleistocene. 

Three debris flows were representative of all the flows 

originating in granite, and an examination of 1948 and 1969 

aerial photographs indicated that none had occurred within the 

last 40 years. Debris flow 2 (figs. 4, 5), 50 m north of debris 

flow 1, consisted of a heterogeneous mass of fragments of the 

granite, sandstone, and metaconglomerate of the Kingston 

Peak(?) Formation, and schist. The snout and the surface of 

this flow were smoother than those of flow 1, and more finegrained material was exposed. Some cobbles at the surface and 

within the soil profile were weathered and easily broken to 

grus. Debris flow 2, visible on 1969 aerial photographs, was 

partially covered during the 1976 flows and had the least 

surface area of all flows measured. 

Debris flow 2 is a thin (25 em thick) deposit overlying 

coarsely bedded fluvial deposits (table 6). A nearby channel 

exposure shows a soil developed in the fluvial deposits with a 

stage II carbonate horizon. Debris flow 2 subsequently buried 

this soil, and the stage I carbonate horizon in the top, or A 

horizon, of the fluvial deposit (table 6) is associated with 

pedogenesis on debris flow 2. 

Annuals growing on flow 2 included Erodium and 

Bromus, with Erodium less abundant on flow 2 than on flow 1. 

The perennial vegetation on flow 2 is dominated by Ephedra, 

with Lycium and .Qrayia contributing significant cover (table 

7). Coleogyne contributes 2.9 percent cover on this flow. 

Debris flow 3, another older flow that is exposed around 

the arms of flow 1 (figs. 4, 5), also originated in the granite. It 

has some strongly weathered cobbles, is fairly smooth, and has 

a distinct terminus (fig. 7). The soil on the deposit (table 6) has 

a stage I carbonate horizon, no variations in soil texture with 

depth, and noB-horizon development. Pebbles in this horizon 

Primary Plant Succession on Debris Flows in Wood Canyon 19 
have continuous carbonate coatings on their bottoms and sides, 

with weak, discontinuous carbonate coatings on top. Debris 

flows similar in soil development and surficial morphology to 

debris flow 3 were the dominant surficial deposit originating 

from the granite. 

Perennial vegetation on debris flow 3 is dominated by 

Coleogyne with 17.6 percent cover (table 7). Ephedra and 

Lycium contribute significant cover, but they have lower cover 

values than on flow 2. Adjacent debris flows, probably 

correlative with flow 3, had Lycium and Salazaria mexicana 

growing out of their cobbl y snouts. Annuals on flow 3 included 

Erodium and Bromus, with Erodium less abundant than on the 

adjacent flow 1. 

Debris flow 4, 100m higher and 1 km southeast of debris 

flow 1 (fig. 4), has been bisected by a wash, thus exposing the 

profile of a soil (table 6). Only small remnants of flows of this 

age, all bisected, occur at the mouths of debris-flow chutes. 

The presence of a cambic B horizon and accumulation of stage 

III carbonate in the soil indicate that this flow is much older 

than flow 3. In addition, the depth to the stage III IIC horizon 

is much greater than the depth to carbonate-enriched cahorizons 

in flows 2 and 3, and stage I carbonate appears in all overlying 

horizons. The respective depths to the stage III carbonate 

horizon and the superjacent stage I carbonate horizons indicate 

a polygenetic history; the stage III horizon was probably 

formed under a wetter climate than the stage I horizons. The 

presence of stage I carbonate in the A horizon suggests that 

upper horizons have been eroded; this is not unexpected given 

the deposit's age and the evidence of channel cutting. 

Coleogyne dominates the perennial vegetation on debris 

flow 4 with 20.6 percent cover, and Ephedra nevadensis 

contributes an additional5.5 percent cover (table 7), less than 

the cover of&_. nevadensis on debris flow 3. The presence of 

Chrysothamnus teretifolius ( 1.0 percent cover) and occasional 

Ephedra viridis individuals on debris flow 4 probably reflects 

the 100-m elevation difference between this flow and the 

others. However, no other difference in floristic composition 

was apparent that could be attributed to a factor other than the 

degree of soil development. 

Debris Flows Originating in Metasedimentary Rocks of the 

Kingston Peak(?) Formation 

Three debris flows originating in the Kingston Peak(?) 

Formation on the south side of Wood Canyon provide 

additional information on primary plant succession (figs. 4, 8). 

Figure 6. Snout of debris flow 1, viewed toward the east with the source area in the background. Photographed December 1981. 

20 Response of Vegetation to Disturbance, Death Valley National Monument, California 
The route of a pipeline from Telescope Peak to Skidoo crosses 

these deposits (fig. 1) along a distance of 0.5 km, with an 

elevation difference of about 60 m. These three flows (A, B, 

and C in fig. 8) are all thickly mantled with vegetation but 

usually have well-defined snouts, poorly sorted matrices, and 

prominent lateral levees. They are representative of all debris 

flows originating from Kingston Peak(?) metasedimentary 

rocks. 

Debris flow A is the lowest in elevation of the flows that 

the pipeline intersects. Stage II carbonate accumulation, a 

desert pavement with dark varnish, a vesicular A12 horizon, and 

an argillic horizon characterize the soil on this flow (table 6). 

Coleogyne dominates the perennial vegetation with 8.2 

percent cover, with Lycium contributing an additional 7.3 

percent cover (table 8). Debris flow C is the highest flow 

intersected by the pipeline corridor, and a stage II carbonate 

horizon, a desert pavement with dark varnish, a vesicular A12 

horizon, and an argillic horizon characterize the soil developed 

on this flow (table 6). Vegetation on flow C is dominated by 

Coleogyne with 13.6 percent cover, and Ephedra nevadensis 

with 6.6 percent cover (table 8). Intermediate-elevation debris 

flow B, 40 em thick and overlying a fluvial deposit, has a soil 

Figure 7. Snout of debris flow 3. Note the similarity with the 

snout of debris flow 1 in figure 6. Photographed June 1981. 

characterized by a stage I carbonate horizon, a desert pavement 

with weak varnish, and a weakly developed vesicular A12 

horizon (table 6). Vegetation on flow B is dominated by 

Acamptopappus shockleyi, Grayia, and Lycium with 7 .8, 7 .6, 

and 6.1 percent cover, respectively; Coleogyne has 2.2 percent 

cover on this flow. 

Estimation of the Ages of the Debris Flows 

The ages of the debris flows can be estimated from the 

degree of soil development. Pedogenesis is a complex 

function of parent material, topography, climate, biota, and 

time (Birkeland, 1974). In Wood Canyon, this complex 

function is simplified because several of the parameters are 

constant. Parent material and topography are similar for the 

debris flows originating in the granite and Kingston Peak(?) 

Formation. Climatic fluctuations during the Holocene have 

been inferred for the northern Mojave Desert (see section on 

"Paleoecology of the Death Valley Region"); however, these 

fluctuations are relatively minor in comparison with current 

climatic variability (Mehringer, 1977) and can be assumed to 

Figure 8. Western Wood Canyon showing the Skidoo pipeline 

corridor and debris flows A, B, and C. The Skidoo pipeline 

corridor appears as a vertical line in the center of the photograph. 

Primary Plant Succession on Debris Flows in Wood Canyon 21 
have had a negligible effect on soil development. Differences 

in the type of vegetation among the debris flows are slight, and 

the influence of these slight differences on soil morphology is 

probably negligible. Thus, differences in soil development on 

the debris flows mainly reflect differences in age. 

The main distinction among the soils on debris flows 1, 2, 

and 3 is the degree to which carbonate has accumulated in the 

C horizons (table 9). The origin of carbonate in the soils of 

Wood Canyon is pedogenic, as distinguished from carbonate 

deposited along drainages (Lattman, 1973). The distinction 

between debris flows 2 and 3 involves a subdivision of the 

stage I carbonate nomenclature ofGileandothers (1981,p. 67; 

see fig. 2 and table 9). The soil on debris flow 2 has continuous 

carbonate coating on the bottoms of pebbles and cobbles, 

whereas the soil on debris flow 3 has continuous carbonate 

coating on the bottoms and sides of pebbles and cobbles. 

Desert varnish cannot be used to distinguish between flows 2, 

3, and 4 because weathering of granite to grus apparently 

occurs faster than varnish can form. 

The soils on the debris flows originating in the Kingston 

Peak(?) Formation are differentiated by soil development and 

desert pavement and varnish. The soil on flow B, the youngest, 

has a lightly varnished desert pavement, no B horizon, and a 

stage I carbonate horizon. The soil on flow A has a wellvarnished desert pavement, an argillic B horizon, and a stage 

II carbonate horizon. The soil on flow C is similar to that on 

flow A, although the B horizon on flow Cis 10 em thicker. The 

difference between the soils on flows A and C is not great 

enough to estimate a difference in age. 

Ages can be assigned to the debris flows based on 

similarity of soil morphology with soils of other comparable 

areas that have been dated radiometrically. Correlations of 

carbonate horizons in different geographic areas are difficult 

because soil carbonate accumulates at different rates in 

response to local climate and dustfall (Bachman and Machette, 

1977, p. 129-130). Consequently, correlations of soils based 

on carbonate morphologies are speculative, and the ages 

assigned are approximations. 

The soil chronosequence developed at Las Cruces, New 

Mexico, is the most detailed and best dated sequence available 

in an environment similar to Wood Canyon. The mean annual 

temperature, seasonal rainfall, and influx rate of carbonate in 

dust are the most important criteria for assessing possible 

differences in carbonate-accumulation rates between the two 

sites. Differences in type of vegetation, typeofparentmaterial, 

and Holocene climatic fluctuations are relatively unimportant 

(see sections on "Soil Processes" and "Vegetation Processes"). 

The mean annual precipitation is similar between the two 

areas, although the precipitation in Wood Canyon is winter 

dominated, whereas that in Las Cruces is summer dominated 

(fig. 3B). However, the leaching index (Arkley, 1963, p. 239) 

is higher for Wood Canyon (52 mm) than for Las Cruces (6 

mm), which suggests that carbonate in Wood Canyon should 

accumulate faster than in Las Cruces. The mean annual 

temperature in Wood Canyon (14 °C) is lower than in Las 

Cruces (16 °C), a difference that also suggests that Wood 

Canyon should be conducive to a faster carbonateaccumulation rate. 

The Las Cruces area receives a high influx of carbonate in 

eolian dust (Gile and Grossman, 1979), and the influx rate is 

believed to be one of the highest in the Southwest (Bachman 

and Machette, 1977; M.N. Machette, oral commun., 1981). 

The influx rate of carbonate in eolian dust is unknown for the 

Panamint Range, but it is assumed to be less than for the Las 

Cruces area. The prevailing winds in the Wood Canyon area, 

inferred from Huning (1978, p. 106-107, 119) and personal 

observations, are from the west and southwest. The mountains 

west of Wood Canyon are composed of Pleistocene volcanic 

rocks and Pliocene and Pleistocene fanglomerates and 

conglomerates derived from Precambrian and Paleozoic rocks 

(Jennings, 1958; Hall and Stephens, 1962); the Precambrian 

and Paleozoic strata are primarily metasedimentary rocks, 

with minor dolomite and limestone. The Argus Range, 30 km 

west of Wood Canyon, is composed of Paleozoic limestone 

and metamorphic rocks and Mesozoic granitic rocks 

(Jennings, 1958). In contrast, the prevailing winds in Las 

Cruces supply carbonate-bearing dust from limestone and 

dolomitic limestone in the Robledo Mountains, 20 km to the 

west. Spring dust storms are common in the Las Cruces area 

(Gile and others, 1981, p. 19), whereas blowing dust is rare in 

the Panamint Range. Therefore, contingent on the hypothesis 

that eolian dustfall is the principal control of carbonateaccumulation rates in desert soils (Bachman and Machette, 

1977, p. 126), the soils of the Wood Canyon debris flows are 

most likely older than those of similar carbonate morphology 

near Las Cruces. 

A comparison of carbonate morphology among soils in 

Las Cruces and Wood Canyon establishes a chronosequence 

for the debris flows. Given that increasing development of 

carbonate horizons indicates increasing age, flow B is younger 

than flows A and C, flow 2 is younger than flow 4, and flows 

3 and Bare probably close in age. Debris flows 2, 3, and Bare 

Holocene in age, based on their stage I carbonate horizons 

(table 6); flows 4, A, and Care late(?) Pleistocene in age. 

Absolute ages can be estimated for the debris flows from 

additional evidence. The climate during the Pleistocene was 

conducive to a greater effective soil-moisture content than has 

been the climate during the Holocene (see section 

"Paleoecology of the Death Valley Region"). This greater 

effective soil moisture (and greater leaching index) 

presumably caused precipitation of pedogenic carbonate at 

greater depths in the soil (Arkley, 1963; Birkeland, 1974). 

Hence, superposition of carbonate in B horizons suggests that 

the soil age is greater than the Pleistocene-Holocene climatic 

change (about 11 ,000 yr B .P.). The superposition of carbonate 

in the IIB2

tca horizon of flow 4 (table 6) suggests that stage I to 

weak stage II carbonate horizons characterize the morphology 

of early Holocene soils. 

We assume that well-developed stage I carbonate 

horizons are characteristic of early Holocene debris flows, and 

that stage II horizons are characteristic of latest Pleistocene 

debris flows. Hence, debris flow 2 is late Holocene in age based 

22 Response of Vegetation to Disturbance, Death Valley National Monument, California 
on a weakly developed stage I horizon. Flows 3 and B, 

assumed of similar age, are middle(?) Holocene in age on the 

basis of stage I carbonate horizons and the weakly developed 

desert pavement on flow B. Flows A and C are latest(?) 

Pleistocene or early Holocene in age on the basis of stage II 

carbonate horizons, well-developed desert pavements with 

varnish, and argillic horizons. Flow 4 is late Pleistocene in age, 

probably older than 25,000 yr, on the basis of its stage III 

carbonate horizon. 

Discussion 

Debris flows are the most common surficial deposits in the 

alluvial fans of Wood Canyon. This dominance is similar to 

that reported for the White Mountains of California (Beaty, 

1974) and at Mt. Thames, New Zealand (Pierson, 1980). The 

proportion of fluvial to debris-flow deposits varies from fan to 

fan (Bull, 1977), but reports of debris-flow deposits as the most 

common surficial deposit appear to be rare, especially for the 

Mojave Desert. However, debris flows appear to be fairly 

common in the Death Valley area (Johnson, 1970; Hunt and 

Mabey, 1966). 

The estimated ages of the debris flows suggests a 

recurrence interval for such events in Wood Canyon. Given 

the order of magnitude of the ages of flows 1, 2, and 3, a 

recurrence interval on the order of millenia is implied. This 

contrasts with Johnson's (1970, p. 438) estimate of a 30- to 

100-yr recurrence interval for flows in the lower canyons on 

the west side of the Panamint Range, and with Beaty's (1974, 

p. 50) assertion that debris flows are a common event in the 

mountainous regions of the Western United States with a 

recurrence of 2-3 per 1,000 yr. 

The vegetation on the Wood Canyon debris flows displays 

a directional change in species composition with time, and thus 

it represents a succession (Mueller-Dombois and Ellenberg, 

1974,p. 374; Pickett, 1976, p. 109). A sequence of perhaps six 

stages occurs that apparently requires longer than 10,000 yr for 

completion. We stress that these stages are completely 

gradational, because each stage represents an arbitrary slice of 

time. The stages are as follows: (1) Annuals such as Erodium 

and Bromus are the initial colonizers of debris flows. Erodium 

was found on 6-mo-old spoil from soil pits. (2) Species 

generally not found in the vegetation immediately adjacent to 

the flows, such as Lupinus, Atriplex, Penstemon sp., 

Eriogonum sp., and Chrysothamnus sp. are the first shrub 

colonizers and are established within several years. (3) 

Additions ofLycium, Grayia, Ephedra nevadensis, and a few 

Coleogyne probably increase the cover to that of the 

surrounding vegetation within a matter of decades. Changes 

occurring after the reestablishment of cover probably occur on 

the order of centuries, but we do not have a deposit of this age 

at this site to support the hypothesis. (4) Ephedra dominates 

with Lycium and Grayia while colonizing species decrease in 

importance. This stage probably requires several thousand 

years for maximum expression. (5) Coleogyne increases at the 

expense of Ephedra, Lycium, and~; this stage probably 

requires up to 5,000 yr. (6) Coleogyne forms a nearly pure 

stand to the exclusion of almost all other species except 

Ephedra. This stage is inferred from vegetation on deposits of 

greater than 10,000 yr in age (flow 4 ), which were deposited in 

a different climate with different ambient vegetation than that 

of today. 

Although allogenic forces appear to predominate, 

autogenic forces contributed to alterations in the soil on the 

1976 debris flows. Many of the individual plants trap organic 

debris and eolian dust. On fluvial surfaces, diverse organic 

material became trapped around the basal areas of most shrubs. 

On the interfluves, the vegetation mainly trapped litterfall, 

which under some plants such as Chrysothamnus nauseosus 

was up to 2 em thick. On flow 1, several of the larger shrubs 

had collected enough debris to create small mounds. On flows 

2 and 3, most of the vegetation, especially Coleogyne, is 

established on mounds. On flow 4, virtually none of the 

subdominants present, such as grasses, grew on intermound 

surfaces. Although grasses were growing more randomly on 

flow 1, greater numbers were found in the collected debris 

under shrubs such as Lupinus and Eriogonum fasciculatum. 

These observations are in agreement with the "fertile island" 

concept developed for the northern Mojave and Great Basin 

Deserts (Charley, 1972; Charley and West, 1975; Wallace and 

Romney, 1980) in which the mounds serve as vegetationmaintained reservoirs of minerals and organic matter that were 

initiated by the first colonizers (Wallace and Romney, 1980). 

The autecology of Coleogyne is an important part of the 

succession. Coleogyne is known for its extremely slow growth 

rate (Bowns and West, 1976) and long lifespan of individuals; 

one individual in Utah has been reported in excess of 400 yr old 

(Christensen and Brown, 1963). Coleogyne is most often 

associated with extremely stable landforms that have 

undergone the maximum soil development found in desert 

environments (West, 1983a, p. 403). In southern Nevada, . 

Coleogyne is associated with coarse-textured, calcareous soils 

(WallaceandRomney, 1972,p. 203; Beatley, 1976,p. 247). In 

Utah, Coleogyne is found on soils with stage IV carbonate 

horizons in nearly pure stands (Bowns and West, 1976, p. 8). 

Coleogyne assemblages were not found on young (2-3 m.y. 

old) basalt flows in southern Utah, although it dominates on 

adjacent soils and older basalt flows (Bowns and West, 1976, 

p. 8). The association ofColeogyne with old soils and the lack 

of Coleogyne on young basalt flows imply either an 

allogenically controlled succession with Coleogyne 

eventually dominating or an affinity of Coleogyne for calcium 

carbonate irrespective of the age of the surface. 

Coleogyne individuals alter soil chemistry. Bowns and 

West (1976) reported an increase in total nitrogen and 

available phosphorus in soil beneath Coleogyne compared 

with intershrub soils. Coleogyne is often clustered on small 

mounds, evidently created by entrapment of eolian materials 

(West, 1983a, p. 403). Charley and West (1975, p. 959), in a 

study of the chemistry of soil beneath typical Great Basin 

Desert shrubs including Coleogyne, presented an idealized 

model showing soil organic matter increasing with time 

Primary Plant Succession on Debris Flows in Wood Canyon 23 
beneath a shrub. Their data indicate that Coleogyne and other 

species significantly alter soil chemistry. 

Coleogyne's germination requirements could also 

explain why it does not initially colonize the debris flows. 

Individual plants produce few seeds (Burgess Kay, written 

commun., 1982), which are relatively large and less mobile 

than those of other species (West, 1983a, p. 408). Bowns and 

West (1976, p. 15, 18) reported that while some Coleogyne 

germinate on the surface, seedlings often emerge from rodent 

caches. Seedling survival was poor, with most seedlings not 

surviving beyond the cotyledonary stage. Seedling 

establishment and survival for most desert perennials occur in 

pulses in years of greater than average rainfall and reduced 

herbivore pressure following years with good seed production 

(Holmgren and Hutchings, 1972; Noy-Meir, 1973; Beatley, 

1975, 1980; Wallace and Romney, 1972). Coleogyne 

assemblages are noticeably depauperate in seedlings and 

young plants (Bowns and West, 1976), an observation 

suggesting that pulse establishment is rare. Hence, Coleogyne 

appears to fit Grime's (1979, p. 48-49) definition of a stress 

tolerator. 

This succession is complicated by several factors. 

Erodium and Bromus are generally believed to be exotics 

introduced from Europe (Munz, 1974, p. 490, 956). However, 

Wester (1981, p. 236-237) reports observations of abundant 

Erodium in California dating from the earliest Spanish 

occupation and believes that Erodium is native. Beatlcy 

(1966) notes that Bromus was introduced into southern 

Nevada before 1925, although Jepson (1925, p. 592) reported 

Bromus to be well established in parts of California by 1925. 

Therefore, the belief that Erodium and Bromus are "exotics" is 

questionable. However, despite the possibility that these 

species are native to central California, their introduction to the 

Mojave Desert appears to have occurred over the last several 

hundred years (see section "Paleoecological Studies in the 

Black Mountains"). Hence, Erodium and Bromus were 

probably not the initial colonizers of fresh debris flows in the 

past. The colonizing species of debris flows older than several 

hundred years are unknown. 

Several incongruities exist between the succession 

observed on debris flows originating in granite and those 

originating in the Kingston Peak(?) metasedimentary rocks. 

Debris flows 3 and B are of similar age based on soil carbonate 

morphology, but flow 3 is dominated by Coleogyne whereas 

flow B is dominated by Acammopappus. Consequently, the 

sequence of succession appears to depend on the type of parent 

material, the elevation and exposure, and the local 

microclimatic variability, and thus it cannot be quantitatively 

modeled without calibration to local conditions. 

RECOVERY OF SKIDOO TOWNSITE AND THE 

SKIDOO PIPELINE 

Human-induced disturbances are common features in the 

Panamint Range, and study of these features allows a 

comparison of primary succession with revegetation over 

relatively short time periods. This comparison is necessary to 

determine if secondary succession is a viable model for 

revegetation of disturbed sites, and consequently whether 

recovery times can be extrapolated from the succession model. 

The townsite of Skidoo was established in 1906 and abandoned 

in 1917. Historical accounts indicate a variety of disturbances, 

including different amounts of compaction and soil disruption 

with known recovery periods. The associated Skidoo pipeline 

corridor crosses many different geomorphic surfaces en route 

to a spring 35 km away, and it provides information about the 

control of geomorphic surfaces on the recovery process. These 

sites are typical of disturbances in the Panamints, and they can 

be used to obtain data for the model of succession. 

Skidoo was built at an elevation of 1,730 m in a small 

valley near the northern extent of the Panamint Range. The 

mountains to the south and west of Skidoo are composed of 

Tertiary granite, while the mountains to the east and north are 

underlain by the Late Proterozoic Noonday(?) Dolomite (Hunt 

and Mabey, 1966, pl. 1). The soil developed on the valley 

alluvial deposits (table 1 0) suggests a Holocene age. The 

vegetation is a Qrav.ia-Lycium assemblage as described by 

Beatley (1976, p. 47-48) that is a transition between Mojave 

and Great Basin Deserts. An Artemisia tridentata assemblage 

occurs on north-facing valley margins as the slope increases, 

and Coleog;yne assemblages dominate on other hillslopes. 

History of Skidoo and the Skidoo Pipeline 

In January 1906, two prospectors located a rich ledge of 

gold in the northern Panamint Range (Greene, 1981, p. 608-

609). By July, 40 claims were established, and the townsite of 

Skidoo was platted in a broad valley 1 km from the workings 

(fig. 9). In September 1906, streets 19m wide were cleared in 

a grid pattern and a townsite map was registered. By May 

1907, the population had grown to 400-500 persons with about 

130 buildings constructed of framed canvas, wood, and iron 

(Greene, 1981, p. 635-636); most of the wood structures lined 

Skidoo Street between 1st and 5th Streets (fig. 10). A 

nationwide financial panic in mid-1907 caused many 

businesses to move or become bankrupt, reducing the 

population to 150 by early 1908 (Greene, 1981, p. 664 ). For the 

next nine years the mine continued to produce bullion, but the 

population steadily dwindled. Only 35 miners were employed 

in 1914 (Greene, 1981, p. 673), and only a "small population" 

remained by 1915 (p. 674; fig. 11). The Skidoo Mines 

Company closed permanently in September 1917 (Greene, 

1981, p. 674-675), and the town was essentially abandoned. 

Skidoo townsite has remained mostly undisturbed since 

1917, although small areas have been disturbed during 

occasional mining operations. In 1922, only one person 

remained and a few buildings were reported still standing 

(Edna Perkins, 1922, quoted in Greene, 1981, p. 675). The 

Skidoo mine was reactivated and worked by 16 men in 1936(p. 

24 Response of Vegetation to Disturbance, Death Valley National Monument, California 
ets· B 1st and . A 1st and 2d Stre ' I' Map is d 

s1tes. ' R d contro · cations of stu y . Old East oa . e 1959 and h of Skidoo townsite . showing Street control; the lo E, ~ ld Aerial East Road, photograph F, was taken'" Jun 

d a

Map erial photograp t· D Montgomeryd s Office in 190 . an y Stree , ' R cor er ) Figure 9. I· C, Montgomer h lnyo County c H&N-F' 8-89 . 2d d Streets contra 'ap registered With t e holograph number re ra wn from f times a m (Eros Data Center p enlarged our 

Recovery o f Skidoo T owns• 't e and the Skidoo Pipeline 25 
676). Within several months, some 30 other men were working 

mines in the area, with the main activity occurring at minesites 

1-2 km west of the abandoned townsite. From 1942 to 1970 

mineral activity was limited, although a tungsten boom in the 

early 1950's caused several hundred claims to be filed. During 

1970, an extensive sampling program in the area resulted in 

about 30 new shafts and 7 open cuts over a 2-ha area northwest 

of the abandoned townsite (Greene, 1981, p. 680). However, 

the only additional disturbance in the townsite apparently 

occurred in the vicinity of Aubery and 3d Streets (fig. 9). In the 

early 1970's, the National Park Service built an interpretive 

sign along Skidoo Street between 4th and 5th Streets; visitors 

since have caused some soil disturbance, which decreases with 

distance from the sign (fig. 9). 

The Skidoo pipeline was built to transport water the 35 km 

between Birch SpringnearTelescopePeak (fig. 1) and Skidoo. 

Construction began in 1906 with 8 km of pipe laid at the 

southern end (Greene, 1981, p. 659). Delays in obtaining 

supplies and rugged terrain limited construction to an 

additional 8 km by the mid-summer of 1907, and the pipeline 

was not completed until December 1907 (Greene, 1981, p. 

652-659). The pipeline corridor ranges in elevation from 1, 730 

A 

to 2,330 m and crosses all exposures on slopes ranging from 0° 

to 32° (fig. 12). 

Only the southern end of the pipeline, from Birch Spring 

to a point north of the crest between Wildrose and Tuber 

Canyons (fig. 1), remains intact today. Easily accessible 

sections were salvaged for scrap in 1917 (p. 675), and the few 

remaining sections were salvaged by the Civilian 

Conservation Corps in 1938 (fig. 13). An access road exists 

along most of the pipeline corridor from Wildrose Canyon to 

Skidoo. Sections of the road are still in use, although most of 

the road has been closed off recently by the National Park 

Service or has been unused since the salvage operations. 

Methods 

Skidoo townsite 

Two periods of recovery (63 and 74 yr) were identified in 

Skidoo townsite. Photographs of the townsite taken in 1906 

and 1907 (fig. lOA) and historical data indicate that 1907 was 

the time of maximum occupation. A 1916 photograph (fig. 

llA) shows the townsite reduced to frame structures, with 

Figure 10. Skidoo townsite. View is toward the southeast. A, In 1907. B, In 1960 (A and B courtesy of Death Valley 

National Monument). C, In 1983 (Raymond Turner, U.S. Geological Survey). 

26 Response of Vegetation to Disturbance, Death Valley National Monument, California 
B 

c 

Figure 10. Continued. 

Recovery of Skidoo Townsite and the Skidoo Pipeline 27 
little apparent habitation. The main part of town between 1st 

and 5th Streets (fig. 9) was active until abandonment in 1917, 

giving a recovery period of 63 yr to the beginning of the present 

study in 1981. The section of Montgomery Street east of 6th 

Street was cleared when the site was originally platted in 1906 

but apparently never occupied, and thus had a recovery period 

of74 yr to 1981. 

A 

B 

Two study sites corresponding to the 63- and 74-yr 

recovery periods were established on Montgomery Street east 

of 6th Street and on 1st and 2d Streets between Montgomery 

and Skidoo Streets (fig. 9). Representative undisturbed sites 

(controls) for each of the disturbed sites were selected on the 

basis of proximity to the disturbed site and the absence of 

obvious disturbances. For the Montgomery Street site, an area 

Figure 11. Skidoo townsite. View is toward the northwest. A, In 1916 (courtesy of Arizona Historical Foundation, Hayden 

Library, Arizona State University). B, In 1983 (Raymond Turner, U.S. Geological Survey). 

28 Response of Vegetation to Disturbance, Death Valley National Monument, California 
bounded by Montgomery, Skidoo, 6th, and 7th Streets was 

selected as its control. An area bounded by Skidoo, 

Montgomery, 3d, and 4th Streets was selected as the 1st and 2d 

Streets control (fig. 9). 

Residual soil compaction was measured by three methods 

for all sites. A simple 30° cone penetrometer was used to take 

70 measurements of penetration depths. A recording 

penetrometer (Carter, 1967) was used to record 100 

penetration resistance vs. depth curves. A thin-walled soil core 

sampler was used to determine 10 bulk densities. Undisturbed 

control sites were no more than 20 m from the disturbed sites. 

Density, percent cover, plant volume, and cryptogamic 

crusts were measured in each disturbed and control site. Belt 

transects totaling 400 m2 in area were sampled for density in 

each site, and cover was measured using 200 m of line 

intercepts. Thirty individuals of each abundant woody species 

were measured at each site to calculate biomass. Cover of 

cryptogamic crusts was estimated at sites as described in the 

"Methods" section. 

The Skidoo Pipeline 

Three recovery periods were identified along the pipeline. 

Where the pipeline was not excavated during the salvage 

operations of 1917 or 1938, the recovery period can be 

assumed to be the 73 yr between the pipeline's completion in 

December 1907 and measurement of soil and vegetation in 

1981. Most of the pipeline in easily accessible areas was 

removed in 1917, and these areas had a recovery period of 63 

yr. Remote sections of the pipeline such as Nemo Crest (fig. 

13) were removed in 1938, and these areas had a recovery 

period of 42 years. 

The Skidoo pipeline was either laid in shallow open 

trenches, buried, or constructed atop a berm or frame structure 

depending on the microtopography of the 2- to 5-m-wide 

corridor. Often all three construction methods were used 

within a relatively short distance. This represents a wide 

variety of disturbance intensity and thus limits measurement 

suitability. The following criteria were used to select pipeline 

study sites: (1) Only sites with obvious trench scars over a 

continuous 0.5 km distance were considered. (2) Dissected 

surfaces and those showing signs of recent erosion or 

deposition were avoided where possible. (3) Only sites with 

relatively continuous lithologies and topography were 

considered. (4) Only sites with continuous, nonpatchy 

vegetation assemblages representative of the general area were 

considered. (5) Sites with signs of recent human or burro use 

were avoided. 

Figure 12. Skidoo pipeline in place west of Birch Spring. The pipeline was not salvaged between Birch Spring and a point north 

of the crest between Wildrose and Tuber Canyons. Photographed June 1981. 

Recovery of Skidoo Townsite and the Skidoo Pipeline 29 
Four study areas were selected, three of which met all the 

criteria outlined above. The Harrisburg Flats study area lies in 

a broad valley 8 km south of Skidoo (fig. 1) and had a recovery 

A 

B 

Figure 13. Skidoo pipeline corridor at Nemo Crest. A, In 1938 

during salvage operations by the Civilian Conservation Corps 

(courtesy of Death Valley National Monument). B, In June 1981 

(Raymond Turner, U.S. Geological Survey). Measurements were 

made in both the road and pipeline corridor, as well as upslope 

and downslope from each. 

period of 63 yr. The pipeline trench enters Harrisburg Flats 

from the north at a bearing of due south and continues down an 

alluvial fan with a slope of 6°. The vegetative assemblage 

occupying this rocky slope is dominated primarily by Ephedra, 

Lycium, Chrysothamnus viscidiflorus, and Haplopappus 

cooperi. The pipeline crosses Harrisburg Flats, an alluvial 

flood plain draining to the west, at an elevation of 1 ,600 m. A 

200-m-wide band of eolian sand covers the edge of the Flats 

between the flood-plain surface and the alluvial fan sloping 

onto it; this sand dune is dominated by an EphedraHymenoclea sal sola assemblage. On the Flats, the assemblage 

is dominated by Grayia and Chrysothamnus. Cover was 

measured using 1,300 m of continuous line-intercept data in 

both disturbed and control sites at the Harrisburg Flats site. 

The Wood Canyon segment (figs. 4, 8) of the pipeline 

route traverses Wood Canyon at a bearing of N. 11 o E., 

perpendicular to an active ephemeral wash in the bottom of the 

canyon. The study area ranges in elevation from 1,585 to 1,645 

m on the 8° north-facing slope of the canyon. The pipeline in 

this area was dis man tied in 1917, a 63-yr recovery period, and 

appears to have been above ground only at the top of the slope. 

Vegetation consists primarily of a Coleogyne-dominated 

assemblage, with a Grayia-Lycium assemblage occupying a 

younger surface that bisects the Coleogyne-dominated 

surface. Cover and density of vegetation in Wood Canyon was 

measured using 900 m of line-intercept data and 600m2 of belt 

transects in both disturbed and control sites. Belt transects 

were centered between the edges of the disturbance zone, 

regardless of the exact location of the pipeline trench within the 

zone, in order to eliminate edge effects. Transects were split 

evenly among the three vegetation zones corresponding to 

debris flows (see section "Primary Plant Succession on Debris 

Flows in Wood Canyon"); transects were placed to avoid any 

ecotonal or geomorphic boundaries, such as active washes. 

The Nemo Crest study area (fig. 13) lies in a broad, 

shallowly concave surface between two ridgetops that define 

the crests ofNemo Canyon to the south and Wood Canyon to 

the north. The pipeline segment crosses a 10°-15° slope 

horizontally with aN. 11° E. bearing and was dismantled in 

1938, a 42-yr recovery period. Dominated by a Coleogyne 

assemblage, the Nemo Crest study area was separated into four 

study sites: an access road last used in 1938, a pipeline trench 

excavated in 1938, and two controls bracketing the road and 

pipeline trench. Cover was measured on 250m of continuous 

line intercepts in each area. An additional 50 m of pipeline 

corridor and adjacent control were measured on a 21°-26° 

slope leading north into Wood Canyon. 

The Wildrose Canyon segment of the pipeline (fig. 14) 

was selected for study based on its dramatic topographical 

variation as the pipeline traverses the steep north-facing slope 

of Wildrose Canyon. Vegetation assemblages change along 

this segment as the elevation increases from 1,625 m at the 

Wildrose Canyon Road to 2,320 m at the crest between 

Wildrose and Tuber Canyons. This segment starts in a 

Coleogyne-Artemisia assemblage, crosses through a 

relatively homogeneous Artemisia assemblage, and 

30 Response of Vegetation to Disturbance, Death Valley National Monument, California 
culminates in a Juniperus-Pinus monophylla assemblage. The 

lower part of the pipeline appears to have been removed in 

1917, while upper parts were removed in 1938 or are still 

intact. Data from this segment are difficult to interpret because 

of the mosaic of environmental and disturbance gradients 

present, although generalities about recovery trends can be 

inferred. Two line-intercept segments, 400 and 900 m long, 

were measured in both the control and disturbed sites of the 

Wildrose Canyon segment. 

Results 

Recovery at Skidoo Townsite 

Soil physical properties have recovered considerably 

during the years since abandonment (table 11; fig. 15). 

Montgomery Street appears to have been cleared of vegetation 

with minimal compaction, based on the similarity in soil 

properties with the adjacent Montgomery control. However, 

Figure 14. Skidoo pipeline corridor across Wildrose Canyon. 

View is toward the north. Most of the pipeline corridor to the 

south of Wildrose Canyon road (center) was measured. 

Photographed june 1981. 

1st and 2d Streets, abandoned 63 yr, were still significantly 

compacted. A linear recovery model suggests recovery times 

of about 90 yr for bulk density and 75 to 80 yr for penetration 

depth. This suggests that Montgomery Street could have been 

6.---------.---------.----,r---~ 

5 

4 

3 

8S 1 fw 

~ 

Montgomery Street -

Control 

j 0~--------~--------~--------~ ~ 6.---------.--.-----,.-----.---~ 

w 

0:: 

<l: 

:::J 

d 5 

(f) 

0:: 

w 

Q_ 

~ 4 0 

fs 

w 

z 3 0 

_.J 

~ 

z 

w 

u 

z 

~ (!}_ 1 (f) 

w 

0:: 

z 

---1 sL 2d Streets Control 

g OL---------~--------~--------~ 

~ 6,---------.---~----.-----~--~ 0:: 

fw 

z 

w 

Q_ 5 East Road/ 

I 

I 

I 

I 

I 

East Road Control 

0~--------~--------~--------~ 

0 10 

DEPTH, IN CENTIMETERS 

15 

Figure 15. Penetration resistance vs. depth curves 

for soils at Skidoo townsite. Bars indicate standard 

error, and dashed lines indicate that the next 

measurement is off-scale. 

Recovery of Skidoo Townsite and the Skidoo Pipeline 31 
compacted to the same level as 1st and 2d Streets because the 

predicted recovery time (75 to 90 yr) is close to the 

abandonment time for Montgomery Street (74 yr). However, 

historical photographs (figs. 10, 11) indicate that no structures 

ever lined Montgomery Street, which suggests that little use 

occurred after the vegetation was cleared. 

Differences between the 1st and 2d Streets site and the 

Montgomery Street site appear to be related to the length of 

recovery period and the intensity and type of disturbance. 

Total live cover of all perennials in the more severely and more 

recently disturbed 1st and 2d Streets site represent only 68 

percent of the total cover found in the 1st and 2d Streets control 

(table 12). Total live cover of all perennials in the lessdisturbed Montgomery Street site represents 108 percent of the 

total cover found in the control (table 12). Differences in the 

total density between the 1st and 2d Street control and 

disturbed sites are not significant, but the total density in the 

Montgomery Street site represents 162 percent of the control 

value. 

Grayia, the dominant genus, contributed about 14 percent 

cover in both controls while contributing only 9.8 percent in 

Montgomery Street and 5.5 percent in 1st and 2d Streets (table 

12). Ephedra and Lycium had higher densities and cover in 

Montgomery Street than in the control, whereas the opposite 

result was found in 1st and 2d Streets. Chrysothamnus 

viscidiflorus contributed 4.2 percent cover and 2,900 

individuals/ha in 1st and 2d Streets, but it contributed only 0.6 

percent cover and 300 individuals/ha in the control. 

Artemisia spinescens, a low, spreading shrub (Wood, 

1966), had more than twice the cover and density in 

Montgomery Street than in the adjacent control. In the more 

severely disturbed 1st and 2d Streets, the cover and density of 

Artemisia are statistically similar to those of the 1st and 2d 

Streets control, which suggests that the severity of disturbance 

affects the colonization ability of this species. Similar 

differences relating to the degree of disturbance can be seen for 

Chrysothamnus nauseosus, Hymenoclea, and Atriplex (table 

12). Apparently, the colonization ability of these species is 

enhanced by compaction. 

The biomasses of the dominant species illustrate further 

differences among sites. Although the mean biomass for 

Grayia was lower in disturbed than control sites (table 13), high 

variability renders any difference among means statistically 

meaningless. However, Chrysothamnus, Lycium, and 

Artemisia appear to have higher biomasses in disturbed than 

control sites. 

Differences in the cover of cryptogamic crusts between 

disturbed and control sites indicate a recovery time of 110 yr 

for complete reestablishment (table 14). The assumption ofO 

percent cover at the time of abandonment can be justified by 

the physical process of blading and the observed lack of 

cryptogam recovery on recently disturbed surfaces (fig. 16). 

Trampling from tourists and burros has probably reduced the 

cover from what it would be in a more isolated area (see 

Anderson and others, 1982b), but it can be assumed that both 

disturbed and control sites were equally affected. There is no 

clear evidence that compaction affects the reestablishment of 

cryptogamic crusts. 

Recovery Along the Skidoo Pipeline 

At Harrisburg Flats (fig. 1), recovery of the Skidoo 

pipeline corridor was measured with a 1 ,300-m continuous 

line-intercept that crossed three distinct vegetation 

assemblages (table 15). A Grayia-Chrysothamnus assemblage 

exists on essentially level ground that is flooded periodically. 

The last flooding occurred during the storms of February 1976 

that caused the Wood Canyon debris flows (see section 

"Primary Plant Succession on Debris Flows in Wood 

Canyon"). Evidence for flood damage could be seen on aerial 

A 

B 

Figure 16. Cryptogamic crusts at Skidoo townsite. A, Fully 

developed crust truncated at left by an active road. B, Typical 

crust in 1st Street. 

32 Response of Vegetation to Disturbance, Death Valley National Monument, California 
photographs and in fine-grained sediments that were plastered 

around the bases of shrubs. Hence, the geomorphic surface 

supporting this assemblage is periodically disturbed and 

therefore geomorphically unstable. Sand dunes north of this 

area, which are dominated by Hymenoclea and Eohedra, are 

also unstable. The third assemblage, dominated by Ephedra 

and Chrysothamnus, occurs on a moderately sloping rocky 

surface dissected by small drainages. 

The 665 m of pipeline corridor along Harrisburg Flats is 

dominated by Chrysothamnus, with a large contribution of 

cover by Grayia (table 15). Parts of this corridor appeared to 

be less disturbed than others, suggesting that perhaps not all the 

vegetation was stripped during either construction of the 

pipeline or its removal in 1917. Species more abundant in the 

pipeline than in the control were Chrysothamnus, Dalea 

fremontii, Atriplex, and Ephedra. The dune-area 

measurements showed little difference between pipeline and 

control except for greater cover of Grayia, Chrysothamnus, 

and A triplex in the pipeline corridor. This perhaps had more 

to do with the exposure of the underlying, more-stable 

substrate than with the successional process. On the rocky 

slope, Haplopappus and Hymenoclea had a higher cover in the 

pipeline corridor, whereas Ephedra, Chrysothamnus, Lycium, 

and Grayia had much higher cover in the control. Of the three 

segments, only the pipeline corridor on the rocky slope had a 

total cover less than the adjacent control. 

These results suggest that substrate and stability affect the 

distribution of individual species. Chrysothamnus appears to 

readily colonize disturbed sites, whether natural or human 

caused, in fine-grained soils, whereas species such as 

Hymenoclea and Haplopappus act as colonizers when the 

substrate is rocky. However, Chrysothamnus was well 

established (6.1 percent cover; table 15) on the rocky slope in 

the main small drainages that dissect the main slope. 

Consequently, microtopographic and grain-size variability 

may control revegetation at local scales. 

In Wood Canyon, three segments of the pipeline corridor 

were studied on old debris flows (debris flows A, B, and C; fig. 

8); the pipeline on these segments was probably dismantled in 

1917. On debris flow A, an assemblage dominated by 

Acamptopappus and Chrysothamnus characterized the 

pipeline corridor, whereas Coleogyne, Lycium, and Ephedra 

characterized the control (table 16). Total cover in the pipeline 

corridor was much less than the cover in the control. On flow 

B, Acamptopappus dominated the pipeline corridor and was 

highest in the control even with only half the cover it had in the 

corridor. Ephedra and Tetradymia spinosa also had a higher 

cover (but not density) in the pipeline corridor, whereas 

Grayia, Lycium, and Coleogyne had a much lower cover than 

in the adjacent control (table 16). The calculated biomasses on 

these flows reflect the differences found in cover (table 17). 

Differences between the pipeline corridor and control were 

less obvious for flow C because both were dominated by 

Coleogyne. In an anomaly not observed at any other site, 

Coleogvne had a higher density in the disturbed area and 

statistically identical values for cover (table 16) and biomass 

(table 17). The equal cover of Coleogyne in the pipeline 

segment and control can be attributed to relatively less 

disturbance in this segment because the pipe was probably 

aboveground. All other shrubs in the control were less 

numerous in the pipeline corridor except for Haplopappus, 

Chrysothamnus nauseosus, C. teretifolius, C. visciditlorus, 

Acamptopappus, and Hymenoclea. Machaeranthera 

tortifolia, an herbaceous perennial, had a much higher density 

in the pipeline corridor. 

AtNemoCrest, the Skidoo pipeline, salvaged in 1938,and 

an abandoned road segment were bracketed by two controls 

(table 18). The species dominant in the control areas, 

Coleogyne, Grayia, Ephedra, and Lycium, all had a lower 

cover value in the road and pipeline, while Acamptopappus, C. 

visciditlorus, and C. nauseosus had a greater cover than both 

adjacent controls. The total cover was much lower in the 

disturbed sites than in the undisturbed sites (table 18). 

On a short (50 m) segment on a 30° slope north ofNemo 

Crest, Artemisia tridentata and grasses contributed the greatest 

cover in the pipeline corridor. Artemisia, Ephedra, Grayia, and 

Coleogyne had much lower cover values in the pipeline 

corridor than in the adjacent control, which had three times as 

much total cover (table 19). 

Cover of perennial vegetation was measured along four 

segments of the Skidoo pipeline corridor in Wildrose Canyon. 

Segment A of the pipeline was built on a rocky, gently sloping 

alluvial fan and passes through an assemblage dominated by 

Coleogyne and Ephedra with 28.7 and 12.9 percent cover, 

respectively. Since the dismantling of the pipe in 1917, 

Coleogyne has recovered to 1 0.4-percent cover, and the entire 

pipeline assemblage contains 40 percent of the total cover of 

the control. Segment B of the pipeline was constructed on a 

steep slope that reaches a maximum of 30°, at the base of the 

divide between Tuber and Wildrose Canyons. The corridor is 

now an open pipeline trench probably dating from 1938 and 

has less than half the total cover of the control. Artemisia, 

Coleogyne, and Ephedra have a much lower cover in the 

pipeline corridor, whereas Chrysothamnus visciditlorus and 

grasses have a lower cover in the control area (table 20). 

Segment C passes through another A. tridentata-Coleogyne 

assemblage on higher slopes with essentially the same 

conditions as segment B. 

Segment D, however, has the longest time of any segment 

to recover because the pipe was still in place 74 yr after 

construction. Again on steep slopes, the total cover was similar 

in the pipeline corridor and control. However, A. tridentata 

contributed greater cover in the pipeline corridor than control, 

while Coleogyne contributed greater cover in the control (table 

20). Other species with a greater cover in the pipeline corridor 

were Eriogonum fasciculatum and Salvia dorii (table 20). 

Discussion 

Measurements in Skidoo and along the Skidoo pipeline 

corridor show that recovery follows a pattern similar to the 

pattern of primary succession observed inWood Canyon. The 

Recovery of Skidoo Townsite and the Skidoo Pipeline 33 
species invading denuded areas generally were predictable, 

and some (especially Chrysothamnus viscidiflorus) were 

observed to be colonizers on debris flows. At Skidoo, C. 

viscidiflorusappeared to be themostimportantcolonizer. This 

species often was found in the center and along the edges of 

active roads, which suggests that it has an ability to colonize 

under high-stress conditions. A summer-flowering species, C. 

viscidiflorus has a low growth habit and produces large 

quantities of seeds (Young and Evans, 1974, p. 132). The 

germination rate for this species must be high because a large 

number of seedlings were observed in disturbed sites. k 

viscidiflorus has increased after disturbance in a variety of 

Great Basin Desert plant assemblages (Young and Evans, 

1974, p. 131), and both it and C. nauseosus produce growth 

earlier in the spring and in greater biomass when competing 

vegetation is removed (McKell and Chilcote, 1957). Other 

species observed to be colonizers include Artemisia 

spinescens and A. tridentata, Atriplex, and Chrysothamnus 

nauseosus. The presence of colonizers that are similar in lifehistory strategy with the colonizers on debris flows in Wood 

Canyon suggests that secondary succession may be a viable 

model for revegetation and recovery of desert plant 

assemblages. 

The role of cryptogamic crusts in the recovery pattern at 

Skidoo is uncertain. Relatively little is known about the 

relationships between cryptogamic crusts and vascular plants. 

Several papers have concluded that the success of cryptogamic 

crusts does not affect the success of vascular plants (Kleiner 

and Harper, 1972; Anderson and others, 1982b). However, 

cryptogams have been found to increase infiltration and 

decrease soil erosion (Fletcher and Martin, 1948; Loope and 

Gifford, 1972; Anderson and others, 1982a), and their role in 

nitrogen fixation is well documented (see Anderson and 

others, 1982a). Anderson and others (1982b) compared the 

cryptogamic crusts in range exclosures, with recovery periods 

between 14 and 38 yr, with those in areas being grazed in 

southern Utah. They found that cryptogamic cover increased 

4-15 percent during the first 14-18 yr of exclusion and only 1 

percent during the next 20 yr. They concluded that 

"reestablishment of cryptogamic crust occurs in at least 14-18 

years and possibly sooner." 

A comparison of the Utah study with the findings from 

Skidoo suggests that the colonizing ability of cryptogams is 

very weak compared with thatofvascularplants. Cryptogamic 

crusts were completely eliminated in heavily disturbed areas of 

the Skidoo townsite, and total recovery, based on a linear 

recovery model, was estimated to be 110 yr. Grazing in 

southern Utah reduced the cover of cryptogamic crusts to a 

value between one third and one tenth of that found in ungrazed 

sites, yet recovery was estimated to take as little as 14 yr. 

Evidently, any surviving cryptogamic crusts considerably 

increase the rate of recovery of the crusts, whereas the superior 

vagility of vascular plants decreases the relative importance of 

survivors in affecting their rate of recovery. This hypothesis is 

also supported by the greater extent of recovery shown by 

vascular plant cover vs. the recovery shown by cryptogamic 

crusts at Skidoo townsite (tables 12, 14). 

PRIMARY PLANT SUCCESSION ON ALLUVIAL 

TERRACES IN GOLD VALLEY AND RECOVERY 

OF GOLD VALLEY TOWNSITE 

The Black Mountains on the east side of Death Valley 

provide a contrast in vegetation with the Panamint Range to the 

west, mainly because of the lower elevations in the eastern 

range. Plant assemblages on the eastern slope of the Black 

Mountains are dominated by Larrea, the most ubiquitous plant 

in the Mojave Desert (Johnson, 1976, p. 138). Vegetation 

growing on alluvial terraces in Gold Valley in the Black 

Mountains (fig. 1) displays a comparable primary succession 

sequence to that found in Wood Canyon in the Panamints. The 

abandoned townsite of Gold Valley, built on one of these 

alluvial terraces, provides a direct comparison between a 

primary succession sequence and revegetation of a disturbed 

site. 

Gold Valley ranges in elevation from 960 to 1,320 min the 

valley and up to 2,060 mat Funeral Peak. Gold Valley townsite 

is at the southern end of the valley at an elevation of 1,310 m 

and a slope of 4° (fig. 17). The townsite is approximately 12 

km by rough dirt road from the more heavily used Greenwater 

Valley road, and hence access to the area is limited. Hunt and 

others (1966, p. B7) estimate a mean annual rainfall for this 

area of 125 to250mm; a more likely range would be 150to200 

mm, as estimated from Kurzius (1981, p. 12-21). 

The discovery of copper and gold deposits in Gold Valley 

caused a mining boom in 1906. The townsite of Willow 

Spring, founded in August 1906, was abandoned in 1907 when 

copper could not be profitably mined. Gold discoveries in the 

south end of Gold Valley caused a second boom in April1907, 

at which time the town of Gold Valley (fig. 17) was founded. 

By December 1907, Gold Valley consisted of a dozen tent 

houses and several buildings (Latschar, 1981, p. 640). The 

abandonment of Greenwater townsite to the north in early 1908 

caused an additional influx of miners, and by March 1908, 

Gold Valley had a population of70 (Latschar, 1981, p. 642). In 

May, 25 tons of gold ore were shipped and a large store was 

built, indicating a high optimism in the town's future 

(Latschar, 1981,p. 642). However, the isolation oftheareaand 

the high cost of mining forced closure of most of the mines in 

the autumn of 1908. Latschar (1981, p. 643) reports that most 

miners left Gold Valley during late 1908 and early 1909. 

Apparently, no attempts have been made to revive mining in 

Gold Valley, and the townsites were not reoccupied. 

The geology of the area is complicated as a result of the 

intense tectonic activity that the Black Mountains have 

undergone since the Mesozoic. Drewes (1963, p. 69) reports 

that the gold mined at Gold Valley came from the Proterozoic 

Noonday Dolomite and Johnnie Formation south of the 

townsite. These blocks were thrust upon Precambrian 

metasedimentary rocks and early Tertiary intrusive rocks in 

early Tertiary time (Drewes, 1963, p. 70). To the north of the 

townsite, Precambrian metasedimentary rocks are separated 

from intrusive and extrusive Tertiary volcanic rocks by a fault 

zone (plate 1 in Drewes, 1963). Tectonism in the Black 

34 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Figure 17. Aerial photograph of Gold Valley showing the location of study sites. A, terrace sequence A; B, terrace 

sequence B; C, terrace sequence C and Gold Valley townsite. Photographed March 1976 (National Park Service 

photograph number DEVA 8-11). 

Primary Plant Succession on Alluvial Terraces in Cold Valley 35 
Mountains has continued through the Quaternary, with the rate 

of displacement on the Black Mountains fault system 

increasing since the late Tertiary (Drewes, 1963, p. 71). 

Tectonism apparently has affected alluvial deposition in 

Gold Valley. Drewes (1963, plate 1) and Denny (1965, plate 

4) depict the alluvium in Gold Valley as "unweathered gravel 

in modem washes," yet a detailed field examination revealed 

a series of alluvial terraces along all major drainageways, 

culminating in truncated alluvial fans with a stage IV carbonate 

horizon. The terraces possibly formed in response to tectonic 

uplift; Denny (1965, p. 32) speculated that more than 30m of 

displacement has occurred along the range-front faults in "the 

last few thousand years." The fan at the mouth of Willow 

Creek, which drains Gold Valley (fig. 1), is cut by six normal 

faults (Drewes, 1963, pl. 1); these faults occur in both old and 

young gravels (Denny, 1965, p. 33). However, the drainages 

in Gold Valley are separated from these faults by the 5-kmlong bedrock channel of Willow Creek, thus eliminating 

knickpoint migration in alluvium as the cause of terrace 

formation. An alternative explanation for the terraces in Gold 

Valley is that they might have formed in response to climatic 

fluctuations. However, terraces per se are not well developed 

atWood Canyon, Skidoo, or the Greenwater district townsites, 

which presumably would have undergone the same climatic 

shifts. 

The vegetation assemblages present in Gold Valley are 

similar to the L.a!n:a-Ambrosia and L.ar.ffia-Lycium-.Qrayja 

assemblages of Beatley (1976, p. 30-32). Gold Valley 

townsite vegetation is part of a broad ecotone between Mojave 

Desert and Great Basin Desert assemblages (Beatley, 1976, p. 

44-46). ~. Co1eog:yne, Ephedra, Q.ooda, and Lycium are 

the most abundant species, with Ambrosia dumosa 

(burrobush) abundant at lower elevations. A list of species 

found in Gold Valley appears in table 4 7. The assemblages 

vary in composition on different terrace surfaces within the 

valley, which suggests a primary plant succession sequence. 

Methods 

Three sites for the study of vegetation assemblages on 

alluvial terraces were established at elevations ranging from 

990 to 1 ,310 m over a distance of 2 km. These sites, labeled 

terrace sequences A, B, and C (fig. 17), consisted of alluvial 

terraces at different heights above the modem drainage. 

Valley cross sections were measured with hand level and stadia 

rod at each terrace sequence. Soil profiles were described and, 

generally, vegetation was measured using 200 m of belt 

transects and 400 m of line intercepts. 

Gold Valley townsite was built on one of the terraces in 

terrace sequence C. For this study the townsite was separated 

into east and west halves because of different intensities of 

disturbance. Bulk densities, penetration depths, and shear 

strengths were measured in both halves of the townsite, a 

nearby undisturbed control, and the active road. Spatial 

constraints required several transects in terrace sequence C and 

the Gold Valley townsite to be shorter than the usual 50-m 

interval. Surfaces for measurement were limited by the 

smaller size of the terraces located near the top of the alluvial 

fan and by the relatively small size of the townsite (see tables 

25, 27). 

Terrace Sequences A and B 

The vegetation assemblages on three alluvial terraces and 

the channel flood plain were measured at terrace sequence A 

(fig. 18). These terraces were labeled on the basis of height 

above the channel flood plain as TA0 (channel flood plain), 

T A1

, T A2

, and T A3 (highest). The composition of the parent 

material appeared to be the same for all terraces, and the depth 

to ground water appeared to be large. The soil developed on 

T A0 consists of 55 em of essentially unweathered alluvium 

overlying a buried stage IV carbonate horizon (table 21). 

Terrace TA1 has a stage I carbonate horizon, with 

discontinuous to continuous pebble coatings, but noB horizon. 

Terrace T A2 displays a cambic B horizon and a stage II 

carbonate horizon. Finally, terrace T ~has an argillic horizon 

with an underlying stage II-III carbonate horizon (table 21). 

Because absolute dating for these terraces could not be 

obtained, a soil chronosequence was developed and age 

estimates were obtained by correlation with soils of known age 

in other areas. The soils on the terraces have formed in 

alluvium dominated by felsic volcanic rocks at a slope of 4° 

and aspect of N. 60° W. Some limestone and (or) dolomite 

from the Noonday Dolomite and Johnnie Formation was 

present as clasts. The rate of carbonate influx in dustfall is not 

known but is probably similar to that in Wood Canyon. 

The terraces of terrace sequence A increase in age with 

height above the drainage (fig. 19). Terrace T A0, the channel 

flood plain, has no soil development and is estimated to be less 

than 100 yr old. Terrace TA1

, which has a soil with no cambic 

or argillic horizon but with a stage I carbonate horizon, is early 

or middle Holocene in age. Terrace T ~' which has a soil 

consisting of a B horizon and a stage II carbonate horizon, is 

latest(?) Pleistocene in age. Finally, terrace TA3, which has a 

well developed B2t horizon and a stage II-III carbonate horizon, 

is late(?) Pleistocene in age. 

Each terrace supports a distinct assemblage of vegetation 

(table 22). Hymenoclea, with a cover of 12.8 percent and 

density of 7,400 individuals/ha, dominates the assemblage on 

TA0 with .J2.a..ka fremontii and Ephedra adding some additional 

cover. Eriogonum inflatum has a high density (2,800/ha) and 

is located predominantly between individuals ofHymenoclea. 

This assemblage is not homogeneous because ~ forms 

patches of several individuals. However, these patches 

generally appear to be on channel bars of older age than the 

channel flood plain. These bars were neither continuous 

enough nor distinctly different from the channel flood plain to 

assign them to a terrace other than T A0• 

~dominated the assemblage on terrace TA1, with 

Ephedra, Ambrosia, and Lycium adding significant cover. The 

high (3,200/ha) density of Ambrosia is indicative of the small 

sizes of the individuals of this species (table 22). On terrace 

36 Response of Vegetation to Disturbance, Death Valley National Monument, California 
TA2, Ambrosia assumes dominance, and Lycium, ~.and 

iliayia contribute significant cover. Hymenoclea and E... 

inflatum are insignificant to the assemblage on T A2

, and 

Ambrosia has almost twice as high a density on terrace T ~as 

on T A1 (table 22). 

Terrace TA3 supports an Ambrosia-~ assemblage 

with few other species well represented, an exception being 

Lycium. The density of Ambrosia (15,000/h.a) is higher than 

the total density for each of the other terraces (table 22). E... 

inflatum and Hymenoclea appear locally where erosion of the 

terraces has exposed carbonate horizons. Acamptopappus 

sphaerocephalus also forms large patches in areas locally 

disturbed. The sides of this terrace, which are actively eroding, 

support a diverse group of species including Hymenoclea, 

Acamptopappus, Salazaria mexicana, }2aka, E... inflatum, and 

Ephedra with scattered ~ and Ambrosia individuals. 

A directional change has apparently taken place from an 

assemblage dominated by Hymenoclea to an assemblage 

dominated by Ambrosia and ~. The percentage 

similarities of terraces T A0, TAl' and T A2 compared with 

terrace TA3 were 6, 71, and 69 percent, respectively, for cover, 

and 21, 41, and 53 percent, respectively, for density. The total 

density of plants on terrace T ~was double the density of each 

of the other terraces, and the total cover on TA0 was slightly 

less than the total cover of each of the other terraces. 

Two terraces were identified along the channel draining 

the southern part of Gold Valley, and these constitute terrace 

sequence B (fig. 17). These terraces occur at an elevation of 

1,140 m. The soil developed in the channel floodplain TB0 had 

a very weak stage I carbonate horizon consisting of 

discontinuous, powdery carbonate coatings on the bottoms of 

pebbles. Terrace TB1, higher than terrace TB0 (fig. 19, table 

21), has a soil with a stage I carbonate horizon. These 

carbonate horizons would suggest that TB0 is late Holocene 

and TB1 is middle or early Holocene in age. 

The assemblage on terrace TB0 is dominated by 

Hymenoclea and Ephedra, with iliayia and Lycium adding 

significant cover (table 23). Herbaceous perennials were well 

represented, with Eriogonum inflatum contributing the highest 

density of these species (2,900/h.a). In contrast, Q..rnyia and 

~ dominate the assemblage on terrace TB2, with 

Thamnosma and Ephedra adding significant cover. The 

herbaceous perennials have decreased significantly compared 

with their density on TB0 (table 23), and two shrubs found on 

terrace TB0

, Eriogonum fasiculatum and ]Laka, were not found 

on TB1• The total density and cover on terrace TB1 are 

considerably lower than they are on terrace TB0, and the 

percentage similarities of the vegetation on TB1 and TB0 are41 

and 35 percent for cover and density, respectively. 

Terrace Sequence C and Gold Valley Townsite 

Five terraces were identified at terrace sequence C, and 

four of these were of large enough areal extent for vegetation 

measurements (figs. 20, 21). The presence of Gold Valley 

townsite on one of these terraces provides an excellent contrast 

between primary plant succession and recovery after disturbance. The lowest terrace in terrace sequence C (TCc) is the 

bottom of a drainage (fig. 21). The soil present on TC0 is 

complex owing to its polygenetic development (table 24). 

Stage II-III carbonate horizons in this soil probably represent 

gully-bed cementation (Lattman, 1973) because they occur 

preferentially in lenses of coarse sand and gravel. These lenses 

were neither parallel with the ground surface nor laterally 

continuous. Pedogenic carbonate consisted of discontinuous 

coatings of carbonate on the bottoms of pebbles (stage I; table 

24). Exhumed stage IV carbonate horizons appeared at 

various locations on the terrace. Terrace TC112 refers to 

channel-bar deposits 25 to 50 em higher than TC0 (fig. 21 ); the 

area of TC112 was too small for measurement. 

Terrace TC1

, approximately 1 m above terrace TC0 (fig. 

21), is characterized by weak stage I carbonate horizons (table 

24). The carbonate occurs as continuous coatings on the 

bottoms of pebbles. This terrace appears to be inset against 

terrace TC2

, which has stage I carbonate horizons with 

continuous pebble coatings and no B horizon. Terrace TC3 

formed the highest terrace in the area, and its soil has a stage 

IT carbonate horizon overlying a buried soil with a stage IV 

horizon (table 24). Terrace TC4 appeared as a remnant among 

the other terraces and has a well-developed pavement, an 

argillic horizon, and a stage II-III carbonate horizon. The soil 

on TC4 is probably correlative with the exhumed soil 

characterized by a stage IV carbonate horizon. 

A chronosequence can be developed from the soils on 

these terraces. Although terrace TC0 is in a drainage way, the 

recurrence time between flow events is large enough to allow 

a soil to develop. The soil on terrace TC1 shows a greater 

degree of development than that on TC0, and hence TC1 is an 

older terrace than TC0

• Similarly, terrace TC2 is older than TC1

, 

and terrace TC3 is older than TC2• The differences in ages 

among these terraces are probably thousands of years. Terrace 

TC0 is late Holocene in age, while terraces TC1, TC2, and TC3 

range from early into middle Holocene in age. The age of 

terrace TC4 is more uncertain but may be middle Pleistocene. 

The vegetation on these terraces follows a primary 

succession similar to that observed on the other terrace 

sequences in Gold Valley. The vegetation on terrace TC0 is 

dominated by Hymcnoclea and Coleogyne (table 25), with 

Coleogyne apparently related to the outcroppings of stage IV 

carbonate horizons. Eriogonum fasciculatum and Ephedra are 

also abundant on TC0

• The vegetation on terrace TC1 is 

dominated by iliayia, Coleogyne, and Lycium, with 

Hymenoclea and Ephedra contributing significant cover (table 

25). Terrace TC2 supports an assemblage dominated by 

Ephedra, Coleogyne, Lycium, and iliayia, with ~ 

contributing an additional 2.2-percent cover (table 25). 

Terrace TC3 is dominated by Coleogyne and ~ with 

Lycium and Ephedra adding significant cover. The vegetation 

on terrace TC4 was not measured because of disturbance and its 

small area; however, the undisturbed vegetation appeared to be 

mostly Coleogyne and~. 

Primary Plant Succession on Alluvial Terraces in Cold Valley 37 
A 

B 

Figure 18. Terrace sequence A in Gold Valley. The foreground of each photograph shows the surface of the respective terrace. A, 

Terrace TA0 (active wash), showing a Hymenoclea assemblage. View is toward the northwest. B, Terrace TA,, showing an 

38 Response of Vegetation to Disturbance, Death Valley National Monument, California 
c 

D 

assemblage with Larrea, Grayia. and Lycium. View is toward the northwest. C, Terrace T ~'showing a Larrea-Ambrosia assemblage. 

View is toward the south. D, Terrace T ~' showing an Ambrosia-Larrea assemblage. View is toward the northeast. 

Primary Plant Succession on Alluvial Terraces in Cold Valley 39 
Gold Valley townsite was built on terrace TC2 (figs. 20, 

21) and shows some recovery of soil and vegetation. The soil 

bulk density and peak shear strength were greater and the 

N 

w 

TERRACE 

SEQUENCE 

B 

s 2 TERRACESEQUENCE !OL A 

0 25 METERS 

EXPLANATION 

E Stage I-ll horizons 

Stage ill-ill horizons 

§ Quartz monzonite 

---- Estimated depth of deposit 

Figure 19. Cross sections of terrace sequences A and B in Gold 

Valley. 

A 

penetration depth was less in the townsite than on undisturbed 

soil on terrace TC2 (table 26). The soil penetration resistances 

(fig. 22) indicate residual compaction on both sides of the 

townsite. The recovery times estimated from a linear model of 

recovery range from 90 to 120 yr for the western townsite, and 

90 yr for the eastern townsite (table 26). The vegetation in the 

west half of the townsite is dominated by Ephedra, 

Hymenoclea, Coleogyne, and Lycium, while the east half of 

the townsite is dominated by Ephedra, Grayia, and Lycium, 

with Coleogyne also significant (table 27). 

Percentage similarity values, calculated for all sites, 

indicate a high degree of similarity in vegetation between the 

townsite and terrace TC2

• The PS values for cover and density 

are 63.3 and 45.5 percent between TC2 and the western 

townsite, 70.1 and 74.4 percent between TC2 and the eastern 

townsite, and 70.0 and 58.1 percent between the eastern and 

western townsites, respectively. However, the PS values for 

cover and density are 46.1 and 29.0 percent between TC3 and 

the western townsite, 37.8 and 44.1 percent between TC3 and 

the eastern townsite, and 57.4 and 51.1 percent between TC2 

and TC3• Therefore, while the similarity is high between the 

townsite and undisturbed vegetation on the same terrace (TC2

), 

the percentage similarity is lower when the townsite is 

compared with an older terrace (TC3). 

Figure 20. Gold Valley townsite and terrace sequence C. The foreground of each photograph shows the surface of the respective 

terraces. A, View is toward the northeast; the terraces and the eastern (E) and western (W) townsite are labeled. B, Townsite location 

on terrace TC2; view is toward the north. C, Terrace TC3

, showing a Larrea-Coleogyne assemblage; view is toward the north. 

40 Response of Vegetation to Disturbance, Death Valley National Monument, California 
B 

c 

Figure 20. Continued. 

Primary Plant Successi n on Alluvial Terraces in Cold Valley 41 
w 

(Gold Va lley townsite) 

------ ~~-, ' ........ ---/.-.....,.._....-,....., 

EXPLANATION 

1:··:·: ::· · ·I Stage I-II horizons m3 Bedrock-- Welded tuff ~,L 

~ 0 

E- ~ 4 Stage III-llZ horizons ---- Estimated thickness of deposits 

0 10 

METERS 

Figure 21. Cross section of terrace sequence C and townsite in Gold Valley. 

6 

A 

5 

a: 

w 

1-

w 

:;::;: 

w 

a: 

~ 6 4 (j) 

a: 

w 

o._ 

(j) 

z 

0 

1-

s 

w 

z 

0 3 ::::! 

~ 

~ 

wu 

z 

;:: 

~ 

(j) 

w 

a: 2 z 

Q 

1-

~ 

a: 

1-

w 

z 

w 

o._ 

DEPTH, IN CENTIMETERS 

Figure 22. Penetration resistance vs. depth curves for soils 

at Gold Valley townsite. A, active road; 8, western 

townsite; C, eastern townsite; D, terrace TC3 control. Bars 

indicate standard error. 

Discussion 

Differences in the species composition of vegetation on 

alluvial terraces in Gold Valley provide evidence for primary 

plant succession in Larrea-dominated assemblages. The 

alluvial terraces are distinguished at three sites by height above 

the modem channel, and they are separated in age by thousands 

of years on the basis of soil morphology (table 28). The stages 

of succession, which are completely gradational, are the 

following for all terrace sequences: (1) The colonizing 

assemblage is dominated by Hymenoclea. This assemblage 

probably persists for decades. (2) Hymenoclea is slowly 

replaced by species such as Ephedra, Dalea, Eriogonum 

fasciculatum, and Ambrosia. (3) ~.Ephedra, Lycium, 

Grayia, Coleogyne, and (or) Ambrosia assume dominance in 

the assemblage, the composition of which varies with 

elevation. This stage appears to be representative of surfaces 

that are several thousand years old. (4) ~.Ambrosia, and 

(or) Coleogyne assume dominance, with other species 

declining in importance. (5) Coleogyne or Ambrosia attains 

higher coverage than Larrea, and few other species are present 

in the absence of local natural disturbances. 

Geomorphic processes exert controls on primary 

succession in Gold Valley. The observation that drainages 

have soils and are mantled with vegetation in terrace sequences 

B and C indicates that floods rarely occur in Gold Valley. 

Discharges in the drainages would scour the channel bed, thus 

destroying any vegetation on the channel bottom; however, no 

denuded channel was observed in Gold Valley. Hence, the 

channel bottoms are probably stable for decades or perhaps 

centuries. Older terraces, formed in response to tectonic or 

climatic factors, are probably relatively stable in the current 

climatic regime. 

The oldest stages of primary succession are unstable, as 

illustrated by the oldest terraces in Gold Valley. Runoff and 

erosion occur on these terraces because desert pavements and 

stage IV carbonate horizons inhibit infiltration of rainfall. 

Hence, eroded areas are common on these terraces, and 

Hymenoclea, Eriogonum inflatum, Acamptopappus, and (or) 

42 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Dalea occur in discrete patches in the disturbed areas. The 

erosion is episodic, and older eroded areas support assemblages with Ephedra, Lycium, and Grayia. Therefore, a 

climax assemblage must be arbitrarily defined as an assemblage on a terrace of finite, although great, age (middle 

Pleistocene in Gold Valley). 

Composite plant assemblages in Gold Valley are difficult 

to explain except by episodic erosion and life-history strategies. Coleogyne contributes 7.0 percent cover and 1,600 

individuals/ha density to the assemblage on TC0, but it also 

dominates the older terrace surfaces. Either Coleogyne has a 

widely variable life-history strategy or else it has an affinity for 

stage III carbonate present at shallow depth. Regardless of the 

cause for Coleogvne's appearance on younger surfaces, 

terraces with exhumed soils are a composite of primary and 

secondary succession sequences. This composite illustrates 

that the distinction between primary and secondary succession 

is ambiguous where a well-developed calcic horizon is present 

in the soil. 

The vegetation in Gold Valley townsite suggests that 

revegetation occurs at a faster rate than the primary succession 

model would suggest. The western townsite, which still has 

compacted soil, supported an assemblage dominated by 

Ephedra, Hymenoclea, and Coleogyne that is comparable to 

the assemblage on terrace TC0 of the upper terrace sequence. 

The eastern townsite was apparently less disturbed than the 

western townsite and supports an assemblage with more 

Qn00.a and Lycium. However, it appears that the stages 

through which succession proceeds are similar in composition 

in primary succession and revegetation. This indicates that 

secondary succession is a viable model for recovery of 

vegetation in disturbed sites. 

RECOVERY OF GREENWATER, KUNZE, AND 

FURNACE TOWNSITES 

You must know just about exactly where Greenwater was 

before you can find its ghost .... Once Greenwater is found, 

though, evidences of its swift flowering and swifter demise 

may be seen scattered through hundreds of acres of 

blackbrush. And in the hills, the great waste dumps look 

freshly mined though more than half a century has passed 

since the final work was done there. Thus they may remain 

a thousand years more .... (Weight, 1969, p. 17). 

The towns of Greenwater, Furnace, and Kunze (the 

Greenwater district) were all built in 1906 and abandoned in 

1908 during the mining boom that also led to the establishment 

of Skidoo and Gold Valley (fig. 1). Observations and 

measurements in the Greenwater district townsites indicate 

revegetation patterns similar to those found in the other 

townsites. All three townsites in the Greenwater district were 

built on alluvial fans with similar parent material, elevation, 

slope, and exposure. A well-documented history and the large 

areal extent of the Greenwater district facilitated a highly 

detailed study of the recovery of vegetation in these disturbed 

sites. 

History of the Greenwater District 

In 1905, copper mineralization on the east slopes of the 

Black Mountains attracted thousands of prospectors (Latschar, 

1981, p. 508). In response to the boom, Furnace townsite was 

established in January 1906, while rival townsites named 

Kunze (also irregularly called Greenwater) and Ramsey were 

established nearby. In the winter of 1906-1907, Kunze and 

Ramsey were abandoned in favor of a merged camp named 

Greenwater, which became the commercial center of the 

district because of its greater potential for expansion. 

The population of these townsites rose and fell with the 

fortunes of the mines, reaching a maximum in early to mid1907. Kunze had a maximum population of about 1 ,000 before 

abandonment. The maximum population of Furnace was 

estimated to be over 1,000 (Weight, 1969, p. 22), whereas the 

population of Greenwater was between 700 and 1,000 at the 

height of the boom. Contemporary newspaper accounts 

(Latschar, 1981, p. 548) indicate that Furnace's maximum 

population was only 500, and that the maximum population of 

the entire Greenwater district was 2,000 in the spring of 1907. 

The Greenwater boom was short lived and has been called 

"a monumental stock fiasco" (Paher, 1973, p. 14) and "the 

monumental mining stock swindle of the century" (Weight, 

1969, p. 31-32). More than $100 million was invested in 

claims over a four-month period of 1906 to 1907. No ore was 

found that could be profitably mined, despite surface 

exposures described as "fantastic," or that would have made 

Greenwater worthy of the title "Greatest Copper Camp on 

Earth" (Weight, 1969). Only 100 miners remained at 

Greenwater by September 1907. The few remaining miners 

were concentrated around two persistent mines, one just south 

of Kunze and the other west of Furnace. The population of the 

entire district was estimated to be 50 in February 1908 

(Latschar, 1981, p. 566). Although the former deputy sheriff 

(and later State senator) Charles Brown reported staying at 

Greenwater until 1909 (Weight, 1969, p. 26), all three 

townsites were effectively abandoned by mid-1908. All 

buildings were quickly scavenged for the scarce wood and 

metal. Work continued at the two mines until1910 with a small 

number of miners involved, and small-scale attempts at 

reviving the district in later years failed (Latschar, 1981, p. 

573). 

The disturbed areas of the Greenwater district represent 

the combined effects of trampling, vehicle use, construction of 

buildings, clearing of vegetation, grading of house pads, 

occasional fires, and limited livestock grazing. Based on wood 

pieces, cellars, and garbage found at the site, combined with 

historical photographs (figs. 23, 26) and modem aerial 

photographs (figs. 27-29), the use history of the site can be 

reconstructed. Streets were cleared of vegetation and houses 

Recovery of Greenwater, Kunze, and Furnace Townsites 43 
were built (figs. 23, 25), although some areas were cleared and 

not used (area in back of town; fig. 24). Automobiles were 

common and driven throughout the townsites (figs. 25, 26). 

Horses were also used (fig. 25), which suggests that some 

livestock grazing must have occurred. The effects of grazing 

were probably limited; Weight (1969, p. 8, 24) reports that 

A 

B 

Greenwater had feedlots and that hay wagons supplied the 

town. Level pads for houses were excavated in the slopes, and 

outhouse holes were dug through the soil caliche; bottle 

hunters in subsequent years dug readily identifiable pits in the 

townsite. Evidence for cutting of "greasewood" (probably 

Larrea) is present only in limited areas of the townsites, and 

Figure 23. Main Street in Greenwater townsite. The foregrounds of the two photographs are probably not identical. 

A, In 1906 (courtesy of the Mojave River Valley Musuem). B, In 1981. 

44 Response of Vegetation to Disturbance, Death Valley National Monument, California 
A 

B 

Figure 24. Hilltop views of Kunze townsite. View is toward the south-southwest. A, In 1906 (courtesy of the Nevada Historical 

Society). Photographs taken later in 1906 show a more extensive development of the townsite before it was moved to 

Greenwater in the winter of 1906-1907. B, In 1983 (Raymond Turner, U.S. Geological Survey). 

Recovery of Greenwater, Kunze, and Furnace Townsites 45 
given the ubiquitous growth of Larrea throughout the 

Greenwater Valley, the report of "scarce greasewood" 

(Latschar, 1981, p. 538) seems exaggerated. 

The Setting of the Townsites 

The Greenwater district lies near the apex of an east-facing 

bajada on the west side of the Greenwater Valley (fig. 1). 

Greenwater was built on a broad alluvial fan at an elevation of 

1,340 m and a general slope of 4 ° (fig. 27). Kunze, located 2.4 

A 

B 

km westofGreenwater, wasbuiltonafanembaymentat 1,430 

m elevation and 5° slope (fig. 28). Furnace was built on 

dissected alluvial deposits at 1,429 m elevation and 11 o slope 

(fig. 29). Ramsey townsite was not located. 

Meteorological data for this area are nonexistent. The 

nearest stations, at noncomparable sites, are Furnace Creek, 

approximately 45 km northwest, and Shoshone, California, 

approximately 40 km southeast. Hunt and others (1966, p. 7-

9) estimated an average annual precipitation of about 130 mm 

and a mean annual temperature of 13-15 oc for the area. 

Figure 25. Main Street in Furnace townsite. View is toward the north. A, In 1906 (courtesy of the Nevada Historical Society). 

B, In 1983 (Raymond Turner, U.S. Geological Survey). 

46 Response of Vegetation to Disturbance, Death Valley National Monument, California 
A 

B 

Figure 26. Locale of the Greenwater Times office at Kunze townsite. View is toward the northwest. A, In 1906 (courtesy of the 

Nevada Historical Society). B, In 1983 (Raymond Turner, U.S. Geological Survey). Note the lack of Larrea behind where the 

buildings stood (double arrows) and the mine tailings (single arrow) that were deposited sometime after the 1906 photograph was 

taken. 

Recovery of Greenwater, Kunze, and Furnace Townsites 47 
Temperature extremes of below 0 oc to above 27 oc were 

reported while the townsites were occupied, as was the 

occurrence of occasional winter snow (Weight, 1969, p. 27), 

which was also documented by us in December 1981 and 

March 1982. 

The alluvial deposits underlying all three townsites were 

derived from Tertiary rhyolite and rhyodacite source materials 

(plate 1 in Drewes, 1963). Drewes mapped the alluvial 

deposits at Furnace as cemented Quaternary gravels and the 

deposits at Greenwater as Quaternary gravels, implying that 

the alluvial surface at Furnace is older. Kunze, built in a 

periodically flooded drainage, has the youngest alluvial 

deposits. 

The gently undulating topography at Green water townsite 

represents a complex history of deposition, as reflected by the 

degree of soil formation on different surfaces. The soil in the 

western part of Greenwater is oldest and is characterized by the 

presence of an argillic horizon and a patchy stage IV calcic 

horizon (table 29); this soil occurs on the tops oflow ridges. In 

the eastern part, soils on ridges have less developed profiles 

and are generally characterized by stage II to stage III calcic 

horizons (control C, table 29). Soils developed in swales east 

of the townsite are younger still and are characterized by well 

developed stage I carbonate horizons (control D, table 29). The 

youngest soil at the Greenwater townsite occurs in a drainage 

east of the townsite and is characterized by a weak stage I 

carbonate horizon. 

Furnace townsite was built on the tops of dissected ridges 

similar to those at Greenwater. The soil at Furnace is 

characterized by a stage I carbonate horizon (table 29) 

overlying a buried stage IV carbonate horizon. The soil 

developed in the drainage at Kunze has a stage I carbonate 

200 METERS 

EXPLANATION 

---- Active road 

--- Abandoned road 

Figure 27. Aerial photograph of Greenwater townsite, showing the location of study sites: A and B, lower Greenwater townsite; C 

and D, lower controls; E, cleared area; F, upper control. Photographed November 1948 and enlarged four times (photograph number 

IF-3 -61 ). 

48 Response of Vegetation to Disturbance, Death Valley National Monument, California 
horizon. The soils at Kunze and Furnace are probably 

correlative with the soil in control D at Greenwater. Surface 

texture of all townsite soils is in the range considered most 

susceptible to compaction (Webb, 1983). 

The vegetation at all three sites is representative of the 

Larrea-Lycium-Grayia assemblage of Beatley (1976, p. 31) 

near the ecotone with the higher elevation Coleogyne 

assemblage. The highest elevation parts of the Greenwater 

townsite (labeled E and F in fig. 27) are part of this ecotone 

boundary. Thirty-two perennial species are found in the 

Greenwater area (table 47), and a similar flora occurs at 

Furnace and Kunze. In the lower elevation Greenwater sites, 

the dominant species are Larrea, Lycium, Menodora 

spinescens, and Ephedra. In the upper elevation Greenwater 

sites, the dominant species are Menodora and Lycium, with 

large contributions from ~. Ephedra, Haplopappus 

cooperi, and H. laricifolius. At Furnace, Menodora, Larrea, 

and Lycium dominate. At Kunze, the vegetation has been 

altered substantially by human occupation, but site elevation 

and vegetation on surrounding hills suggest a similarity with 

the Furnace site. The young age of the soil at Kunze and 

possible disturbance from flooding would imply that the 

undisturbed vegetation at other sites in the Greenwater district 

is not analogous to the vegetation at the Kunze townsite prior 

to occupation. 

Methods 

Study-Site Selection 

Several study sites were established to determine recovery 

(figs. 27-29). At Greenwater, the study sites consisted of a 

section of townsite with graded house pads (labeled A in fig. 

27); a section cleared but with less evidence of use (labeled B); 

two control sites with different soils (table 29) on slightly 

different topography for comparison with A and B (labeled C 

and D); a cleared but probably unused site 600 m upslope from 

C and D (labeled E); and a control adjacent toE (labeled F). In 

addition, the vegetation within house-pad areas and Larrea 

individuals were measured in the general townsite and 

compared with measurements at controls C and D. Soil in an 

abandoned road crossing townsite B was measured for residual 

soil compaction. Sites A, B, C, D, and the general townsite are 

in a vegetation assemblage with significant Larrea in the 

undisturbed site, whereas sites E and F are in an ecotonal 

boundary site generally devoid of Larrea. 

At Kunze, a study site was located in the main portion of 

the townsite, but no suitable control site was located (fig. 28); 

the townsite is within a Larrea assemblage, but spatial 

heterogeneity in species composition, topographic 

irregularities, and the general small size of comparable, 

200 METERS 

EXPLANATION 

---- Active road 

Figure 28. Aerial photograph of Kunze townsite, showing the location of the study site. A, townsite. Photographed November 1948 

and enlarged four times (photograph number IF-3-61 ). 

Recovery ofCreenwater, Kunze, and Furnace Townsites 49 
undisturbed sites precluded measurement of a control site. At 

Furnace, study sites were located in a portion of the townsite 

(labeled A in fig. 29) and a control site situated in an unused 

city block (labeled B). 

Soil and Vegetation Measurements 

Soil compaction was measured with a simple 30° cone 

penetrometer. Other soil measurements were not performed 

because of the high gravel content of the soil (table 29). The 

soil was air-dry at the time measurements were taken. The 

Shapiro-Wilk W-test (Shapiro and Wilk, 1965; Mark, 1978) 

was used to test the hypothesis that penetration depths are 

normally distributed; in general, the hypothesis that the 

distribution of penetration depths was normal could not be 

rejected at the 95-percent confidence level. 

Vegetation measurements included density, percent 

cover, and dimensions of individual plants. Densities were 

obtained from 400-m2 belt transects, and percent cover was 

determined from 400 m of line intercepts in each study area. 

Shrub heights and minimum and maximum diameters were 

measured on 30 individuals of each abundant woody species in 

order to calculate volumes; at Greenwater, 50 Larrea 

individuals selected throughout the townsite were compared 

with 50 individuals in control C. Shrub biomass was estimated 

for each species for which shrub volume data could be 

collected. 

Results 

Recovery of Compacted Soils at Greenwater and Furnace 

Townsites 

Soil penetration resistance measurements revealed 

residual compaction in an abandoned road and all disturbed 

sites except sites Band E (table 30). Hence, plants attempting 

to colonize most of the disturbed sites faced soils with high 

density and high strength, whereas plants colonizing the 

cleared areas faced less harsh conditions. If it is assumed that 

penetration depth increases linearly with time, a complete 

recovery time for the compacted soil is estimated to be 100 yr 

for Furnace, 100 yr for townsite A, and 110 yr for the 

abandoned road in townsite B. 

EXPLANATION 

----Active road 

--· Abandoned road 

Figure 29. Aerial photograph of Furnace townsite, showing the location of study sites, A, townsite; B, control. Photographed 

November 1948 and enlarged four times (photograph number IF-3-61 ). 

50 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Recovery of Vegetation at Greenwater Townsite 

The cleared areas at Greenwater townsite have undergone 

substantial revegetation in the 73 yr since abandonment. Total 

cover is similar between disturbed and control sites, and only 

minor differences were measured between controls. However, 

the disturbed sites can be readily distinguished from 

undisturbed sites because of shifts in species composition, 

cover, and biomass, as well as the apparent slow 

reestablishment of~ (table 31). 

At the lower Greenwater sites, the cover of Lycium, 

Menodora, and~ is much less in the disturbed sites A and 

B than in either control C or D (table 31, fig. 27). These 

differences far surpass differences'between controls C and D 

caused by soil differences (table 29). The cover ofElJhedra is 

lower in site A but not in site B, while Qralla cover is lower 

only in site B. Hymenoclea and .s.ti,ua SlJeciosa have a greater 

cover in sites A and B than in the controls (table 31). 

HalJIOlJ3lJlJUS sp. generally had a higher cover in site A than the 

controls, but this species exhibits a high spatial variability and 

tends to clump. Only minor differences were measured 

between controls, with the lower cover of Lycium and higher 

cover of HalJIOlJalJlJUS sp. in control D the most important. No 

consistent differences in species cover were observed between 

sites A and B, despite the lack of compaction in site B (table 

30). The density of vegetation in sites A and B was roughly 

similar to the density of vegetation on 16 house pads 

distributed throughout Greenwater townsite (table 35) with 

respect to the paucity of ~. Lycium, Menodora, and 

ElJhedra. 

The disturbed sites in the lower townsite had a higher total 

density and a lower density of long-lived shrubs than the 

control sites. Hymenoclea had a much greater density in sites 

A and B than the controls, whereas the density of Lycium, 

EQhedra, Menodora, ~.and Qralla was lower in all of the 

disturbed sites (table 31). Generally, Hymenoclea, StWa. and 

herbaceous perennials contributed the largest density in the 

disturbed sites, while woody shrubs contributed the largest 

densities in the controls. 

In the upper Greenwater site, the cover of Menodora, 

Lycium, and ili.ayia was lower in the cleared site E (table 30) 

than control site F (table 3 2). The cover of ElJhedra was similar 

in both sites, while the cover of HalJlOlJalJlJUS sp., Hymenoclea, 

and .s..t.Wa were greater in the cleared site. Total live cover was 

similar in the two sites, but the cover contributed by shrubs was 

much lower in the cleared site than in the control (table 32). 

The densities ofHymenoclea and SlWa were much greater and 

the densities of other woody shrubs were much less in cleared 

site E than in control F. 

The most striking difference in shrub volumes was 

between~ sizes in disturbed sites vs. controls (fig. 30). 

Data from both Greenwater and Furnace controls show a 

similar unimodal distribution of ~ volumes, whereas a 

distinct bimodal distribution of volumes was found in the 

disturbed sites. In each case, the means were not significantly 

different, yet the volume distributions were obviously 

different. A possible explanation of this phenomenon may be 

the decreased competition for water among~ individuals 

left standing after the townsites were constructed. These 

individuals increased in volume by taking advantage of the 

excess water not used by other perennials and are represented 

in the histogram by the peak in the large volumes (fig. 30). 

Seedlings established after abandonment of the townsite 

encountered increased competition from established Larrea 

individuals and other reestablished species or simply grew 

slowly with respect to the 73-yr abandonment time; this is 

illustrated by the peak in the smaller volumes (fig. 30). 

Larrea in the control sites also showed a strong tendency 

toward clumping of individuals, whereas individuals in the 

disturbed sites were usually solitary. The majority of clumped 

Larrea in the controls may be clonal rings, which indicates that 

these are very old individuals (Vasek, 1980b). The solitary 

individuals could be either relatively recent recruits or 

(/) 

z 

8 

Q 4 

a: 

~ UJ 

Greenwater 

townsite 

~ QL_~~L_~~~LL~iJ--LLL-~~~~~~~ 

012~--.----r---.----~---r--~----r---~~ 

lL 

0 

a: 

UJ 

c:o 

~ 

~ 

z 

8 

B 

Greenwater 

control 

-2 

LOG BASE e OF VOLUME, IN CUBIC METERS 

Figure 30. Histograms showing volumes of individual Larrea 

tridentata. A, In Greenwater townsite (50 individuals). B, In 

Furnace townsite (30 individuals). 

Recovery of Greenwater, Kunze, and Furnace Townsites 51 
remnants of destroyed clonal rings. Similar patterns can be 

detected in the distributions for other species, but these 

differences in distributions are not as striking as those for 

~between disturbed and control sites. 

Fundamental differences were observed in the 

distribution of biomass among shrub species. Hymenoclea 

always had a much greater biomass in disturbed than control 

sites (tables 33-35), while the biomass of species dominant in 

control sites (such as Menodora, Lycium, and ~) was 

always less than in the disturbed sites. Some species, such as 

Euhedra, showed little biomass differences between disturbed 

and control sites, while the biomass of Hauiouauuus sp. was 

too variable to allow comparisons. In general, the large errors 

associated with the biomass calculation (as much as 50 

percent) preclude meaningful conclusions except in the cases 

of obvious large differences, and certainly they prevent a 

meaningful estimation of total biomass for the sites. 

Recovery of Vegetation at Furnace and Kunze Townsites 

Furnace and Kunze townsites showed a pattern of 

revegetation generally similar to the Greenwater townsite but 

with some important differences. As was the case at 

Greenwater townsite, the disturbed sites generally supported a 

higher cover of .s..tWa and Hymenoclea and a lower cover of 

Menodora and~ than the Furnace control site (table 36). 

However, the cover of Hauiouauuus sp. was much lower in 

Furnace townsite than in the control, whereas generally the 

opposite was true at Greenwater townsite. Dyssodia ~. 

an herbaceous perennial, contributed a relatively large cover in 

Furnace townsite compared with the control, whereas little 

difference between control and disturbed sites was measured 

at the lower Greenwater townsite. 

The total covers in Furnace townsite and control were 

similar (table 36), although they were lower than at 

comparable sites at Greenwater. The cover contributed by 

shrubs at Furnace townsite was the lowest of any of the 

disturbed sites. In a manner similar with the Greenwater sites, 

Hymenoclea, .s..tW.a. and herbaceous perennials contributed the 

greatest density in the townsites, whereas other woody shrubs 

contributed the greatest density in the Furnace control (table 

36). 

Shrub volumes followed a pattern similar to that observed 

at Greenwater townsite. ~in Furnace townsite showed a 

strong bimodal distribution, as discussed previously (see fig. 

30B). Some other species, particularly .G.ray.ia, also showed an 

apparent bimodal distribution of volumes in the townsite 

compared with an apparent unimodal distribution in the 

control. Statistical comparison of mean volumes revealed a 

significantly greater volume for Hymenoclea in Furnace 

townsite than in Furnace control. All other volumes were 

found to be statistically similar, although the mean volume of 

~was 70 percent greater in Furnace townsite than in 

Furnace control. 

Biomass calculations revealed patterns similar to those 

found at Greenwater (table 37). The dry-weight biomass of 

Hymenoclea was much greater in Furnace townsite than in 

Furnace control. The biomasses of Menodora and Lamia were 

much lower in the townsites than in Furnace control, whereas 

little difference could be discerned between townsites and 

control for Euhedra and Lycium. 

Discussion 

The data and observations on vegetation in the 

Greenwater district can be used to formulate a model for 

secondary succession. Hymenoclea appears to be the first 

perennial to colonize recently disturbed sites at Greenwater, 

with Euhedra and Thamnosma also of importance as 

colonizers. A lightly used road at Furnace had Hymenoclea on 

its shoulders and median. Haulouauuus, Lycium, and .G.ray.ia 

become established with Hymenoclea within a timespan on the 

order of the time since abandonment. Menodora and ~ 

apparent! y assume dominance after a much longer time period. 

~· s response to disturbance affects the interpretation 

of recovery. ~is a highly visible shrub in the Greenwater 

district, and its presence and absence is easily detected on 

aerial photographs (figs. 27 -29). Its low density is offset by its 

height, a characteristic of this species (Heatley, 1974 ). Larrea 

has a conspicuously low density and cover in Greenwater 

district townsites, a result not expected based on ~·s 

relatively early appearance in primary succession sequences in 

Gold Valley. However,~ is at its upper elevationallimits 

in Greenwater and could be limited by too much precipitation 

(Heatley, 1974). To test climatic change as an influence in 

recovery of disturbed sites, pack rat middens were analyzed 

near Greenwater townsite (see section on "Paleoecological 

Studies in the Black Mountains"). 

Little information is available concerning the life-history 

strategy of Menodora (Beatley, 1976, p. 214-215; Jaeger, 

1941, p. 181; Munz, 1974, p. 589). However, Menodora is 

inferred to be a stress tolerator based on its similarity with 

~ in distribution among control and disturbed sites; its 

shoot morphology, consisting of short, stout, spiny branchlets; 

its low, lateral crown spread; and its apparent low palatability. 

The plant appears to tend toward a more competitive strategy 

than ~ as suggested by its phenology and frequency of 

flowering during periods of maximum potential productivity, 

by leaf phenology composed of well-defined peaks of leaf 

production, and by relatively short longevity of leaves. 

The species of uncertain importance in the successional 

sequence are Euhedra, Tetradymia, and Haulouavuus sp. 

Ephedra behaves partly like Hymenoclea in its colonization of 

disturbed sites through both root-crown sprouting (Vollmer 

and others, 1976) and seedling establishment. Euhedra has 

been termed a "long-lived" species (Vasek and others, 1975a), 

also implying a similar strategy as ~. and has been 

recommended for the artificial reseeding of disturbed sites 

(Kay and others, 1977c). It has many characteristics of a stress 

tolerator, including small, ephemeral leaves, photosynthetic 

stems, and a regenerative strategy of low seed production and 

vegetative propagation via lateral spreading of the root crown. 

52 Response of Vegetation to Disturbance, Death Valley National Monument, California 
However, Evhedra's life-history strategy is more similar to a 

stress-tolerant competitor than a stress tolerator because of its 

ability to colonize relatively quickly, its ability to propagate 

vegetatively, and its shoot morphology. 

Havtovavvus sp. also appears to have an ambiguous 

strategy within the townsites, possibly depending upon its 

viability within the undisturbed assemblage. At Furnace, the 

cover of Haviovavvus was l;:;ss in the townsite than in the 

control, whereas in Greenwater townsite Havtovavvus usually 

contributed greater cover in disturbed sites. Havtovavvus 

contributed about three to five times the cover in the controls 

at Greenwater than in Furnace control, and this observation 

suggests that the Furnace site is not favorable for its growth. 

The relative importance of Havtovavvus sp. in the 

undisturbed vegetation at Greenwater indicates a strategy 

similar to stress-tolerant competitors. Therefore, 

Haviovavvus sp. are in a position somewhere between the 

stress-tolerant ruderal and the stress-tolerant competitor 

strategies. 

PALEOECOLOGICAL STUDIES IN THE BLACK 

MOUNTAINS 

Plant succession in Death Valley cannot be considered 

independent of climatic influences. Five of the six townsites 

studied (including Wahmonie; Webb and Wilshire, 1979) 

were close to the upper elevation limit of~ According 

to the primary succession sequence from Gold Valley, ~ 

individuals should be in disturbed sites but instead are 

conspicuously absent. Either a cooling trend during the last 

several hundred years (LaMarche, 1973) or wetter conditions 

could explain the low density and cover ofL.a!:Jldl seedlings in 

disturbed sites, because germination of LaJ:wi is limited by 

temperature and precipitation (Beatley, 1974). 

To test the degree of climatic influence, a series of modern 

and fossil packrat middens were collected south of Greenwater 

townsite (fig. 1). This midden series records the extent of 

change in vegetation assemblages in the Black Mountains 

during the last 2,000 yr. These changes can be used to infer 

climatic fluctuations that could have influenced the vegetation 

assemblages at other sites in the Death Valley area (also see 

Cole and Webb, 1985). 

Methods 

A hill near Greenwater townsite (fig. 31) was chosen for 

the midden study. This hill, composed of rhyolitic volcanic 

rocks, supports a~assemblage below 1,350 m elevation, 

and a Coleogyne assemblage starting at a slightly higher 

elevation. ~-dominated assemblages are characteristic of 

low-elevation Mojave Desert, while Coleogyne-dominated 

assemblages are characteristic of the higher elevation 

transition between the Mojave and Great Basin Deserts 

(Beatley, 1976). The two dominant species are mutually exclusive on this hill, and the upper elevation limit of~ and 

lower elevation limit of Coleogyne are referred to here as the 

~-Coleogyne limit. 

We hypothesized that a change in the ~-Coleogyne 

limit at a given time would reflect the prevalent climatic 

conditions. ~·s upper elevation limit appears to be 

controlled by precipitation because the elevation and latitude 

limits of Larrea in Nevada coincide with a maximum mean 

precipitation of 183 mm, and because the viability of L.a!:.rul 

seeds decreases considerably when the mean annual 

precipitation exceeds 150 mm (Beatley, 1974). Coleogyne 

assemblages are best developed where the mean annual 

precipitation exceeds 200 mm (Beatley, 1975). The 

temperature requirements of the two species overlap (Beatley, 

1975); hence, a shift in the Lam-Coleogyne limit should 

indicate a change in mean annual rainfall but not necessarily in 

mean annual temperature or in temperature extremes. 

To test this hypothesis, eight fossil and five modern 

middens were collected between 1 ,340 and 1 ,410 m elevation 

(see bottom of table 38). Exposures ranged from northeast to 

southeast, and xeric conditions increased in more southerly 

exposures and at lower elevations. All middens were collected 

from sites with a similar rhyolitic substrate, a procedure that 

thus eliminated substrate as a source of variability. Two 

modern middens-G8 and GIS (table 38)-were collected to 

represent the most xeric, ~-dominated sites on the 

hillslope; a third modem midden (G7) was collected to 

represent the most mesic, Coleogyne-dominated sites. One 

modem and six fossil middens were collected within a 20-m 

radius at the Lam-Coleogyne limit, and one modern and two 

fossil middens were collected at a site 60 m above the limit 

(table 38). 

The contents of the fossil middens were quantified to 

obtain a statistical analysis of changes with age. Cole and 

Webb ( 1985) provide details of the methods used. The 

concentration of each taxon was quantified as the logarithm of 

the number of identifiable fossils per kilogram of washed 

midden matrix. The concentrations were analyzed using 

principal-components and factor analysis (Gauch, 1982). The 

input matrix was similar to table 38, except that annuals and 

species found in less than three middens were excluded. Both 

methods calculated a matrix of correlation coefficients 

obtained from comparison of each midden with all other 

middens. Factor analysis (oblique rotation) differs from 

principal-components analysis in the selection of reference 

axes; principal-components analysis selects axes to account 

for the maximum amount of variance among the middens, 

whereas factor analysis uses the dissimilar (least correlated) 

middens to select axes. 

Results 

The eight fossil and five modern middens collected from 

the hill south of Greenwater illustrate species composition 

changes over the last 2,200 yr (fig. 32). Lam has decreased 

in fossil concentration during the last 270 yr, but this decrease 

may not be statistically significant. Coleogyne, however, has 

Paleoecological Studies in the Black Mountains 53 
become established only within the last few hundred years. It 

is represented in all five modem middens and fossil midden 

G6b (270 yr B.P.) and is absent from the seven older middens 

(table 3 8). Coleogyne fossils are the most abundant in middens 

G7 and G lla (table 38), both collected adjacent to Coleogyne 

individuals at 1,360 and 1,410 m elevation, respectively 

(table 38). The other three modem middens, more distant 

from Coleogyne individuals, record seed dispersal 25 to 50 m 

from the individuals. The absence of older Coleogyne 

macrofossils, especially from middens G 11 band G lie (table 

3 8) indicates that the Larrea-Co leogyne limit was above 1 ,410 

m on this hillside until the last several hundred years. 

Tetradymia spinosa was not found in any fossil middens but 

was relatively abundant in three of five modem middens (table 

38). Eriogonum fasciculatum and Grayia also increased in 

concentration during the last 750 yr (fig. 32), but the trends 

are not as distinct nor are the species as well represented as 

Coleogyne is in the modem middens. 

Principal-components and factor analysis were used to 

examine trends within the variability of the macrofossil 

concentrations (fig. 33). The total variance explained with the 

first two principal-components axes (fig. 33A) was 66 percent, 

with the total variance explained for individual middens 

ranging from 44 to 90 percent. Two modem middens 

representing the most xeric sites on the hillslope, G8 and G 15, 

Coleogyne 

Larrea 

are clustered with the oldest middens at the bottom of the 

ordination (fig. 33A) while the other modem middens appear 

at the top. The arrows on figure 33 illustrate temporal trends 

from older middens (clustered with modem middens G8 and 

G 15) to modem middens collected at the same site. The factoranalysis (oblique rotation) ordination (fig. 33B), with the most 

dissimilar middens used as X-axis endpoints, shows clearer 

temporal trends. Middens G8 and G 15 are clustered with the 

older middens, and a series of nearly straight lines connect 

these middens with the other modem ones at the lower left (fig. 

33B). 

The principal-components scores (table 38) indicate the 

species responsible for the clustering patterns. Larrea and 

Haplopappus are the most important determinants of the Xaxis position because of their high positive values. These 

species also have the highest fossil concentration for all 

middens (table 38). However, those species showing high 

positive values for theY -axis, such as Eriogonum fasciculatum 

and Ephedra sp., are near their lower elevation limit on this 

hillside, while those species with high negative values, 

particularly Larrea and Ambrosia, are at their upper elevation 

limit. On the basis of the principal-components scores, theYaxis appears to reflect site differences resulting from elevation 

or time, whereas the X -axis reflects the most abundant species, 

sample variability, and some elevation or time aspects. 

Figure 31 . Fossil packrat-midden collection site near Greenwater townsite. Dashed line indicates approximate upper elevation limit 

of Larrea and lower elevation limit of Coleogyne. Arrow ind icates rock outcrop where most of the middens were collected. View 

is toward the west. 

54 Response of Vegetation to Disturbance, Death Valley National Monument, California 
The ordinations suggest that the Larrea-Coleogyne limit 

has shifted downward in elevation with time. Older middens 

are less similar to modern middens collected at the same site 

than to modern middens found at more xeric sites. Coleogyne 

appears only in middens younger than 270 yr B.P. Because 

Coleogyne is absent from all fossil middens except G6b and 

now occurs as low as 1,360 m, its lower elevation limit has 

decreased a minimum of 50 m within the last several hundred 

years. 

Discussion 

Packrat middens collected near Greenwater townsite 

indicate that climatic fluctuations during the late Holocene 

have affected species near their elevation limits. Wetter and 

possibly cooler conditions starting approximately 500 yr ago 

fz 

LU 

rJl 

LU 

a: 

a... 

LU 

a: 

0 

l.L 

LU 

(() 

rJl 

a: 

<! 

LU 

>-

0 

270 

290 

400 

740 

1340 

2105 

2125 

2235 

0 2 0 0 0 3 0 3 0 4 0 

are probably responsible for the decrease in the lower elevation limit of Coleogvne. This corresponds to the "Little Ice 

Age" (Flint, 1971, p. 524) and a lowering of the upper treeline 

in the White Mountains of California (LaMarche, 1973; fig. 

32). 

The packrat-midden data suggest that germination of 

Larrea may be restricted in the townsites because of climatic 

factors. Beatley (1974, p. 259) states that high rainfall is 

detrimental to the reproduction of Larrea, and that minimum 

air temperatures were responsible for exclusion of Larrea from 

closed basins. However, Beatley (1974, p. 245) concludes that 

upper elevation limits of Larrea are controlled by mean annual 

precipitation. Larrea may have become established at its 

current elevation limits prior to the wetter period of the last 500 

yr and is now either not reproducing or reproducing at a greatly 

reduced rate. The destruction of relic stands of Larrea could 

explain the absence of Larrea from townsites near its upper 

elevation limits. 

3 0 0 0 4 0 50 100 

LOG MACROFOSSILS PER KILOGRAM OF WASHED MIDDEN MATRIX ALTITUDE ABOVE 

MODERN TREELINE 

!WHITE MOUNTAINS), 

IN METERS 

Figure 32. Change in concentration of plant macrofossils with time in middens collected from the vicinity of Greenwater townsite. 

Treeline data are adapted from LaMarche (1973). 

Paleoecological Studies in the Black Mountains 55 
2.5~----------------------.----------------------,-----------------------, 

A 

400 

2.0 

290 

y 1.5 

1.0 

M G4b2 

0 

G8 G4b1 

0.5 

1.5 2.0 2.5 3.0 

2.4 

B 

2125 

1.8 M~b1 

1340 0 

G15 

1.2 

G9d 

2105 

y 

0.6 

M 

0 

G7 

G4a 

0.0 

G11b 

-0.6 L-------------~--------------~--------------~------------~------------~ 2.4 3.0 3.6 4.2 4.8 5.4 

X 

Figure 33. Principal-components analysis and factor analysis of the contents of fossi I packrat middens from the 

vicinity of Greenwater townsite. Number above each data point is the midden age in years before present. M 

indicates a modern (less than 200 yr B.P.) midden. Code below or to the side of each data point identifies the 

midden (see table 38). A, Principal-components ordination. 8, Factor-analysis (oblique rotation) ordination. 

56 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Erodium sp. (probably E. cicutarium) and Bromus fossils 

were only found in modem middens G4a, G7, and G 15, and in 

the 270 yr B.P. midden G6b (table 38). The absence of 

Erodium and Bromus fossils in middens older than 270 yr B.P. 

indicates that these two species have only occurred on this 

hillside in the last several hundred years. These species are 

now common throughout the Black Mountains (Schramm, 

1982), which indicates that climate is not a factor in their 

presence/absence in middens. This observation suggests that 

Erodium and Bromus can be considered exotic to the 

Greenwater townsite, and it provides additional information 

on the status of these "introduced" species (Beatley, 1966; 

Wester, 1981). 

A MODEL OF SUCCESSION IN DEATH VALLEY 

Definition of Succession 

Studies of plant assemblages in Death Valley National 

Monument indicate sequential, directional changes in species 

composition take place after disturbance, and thus that plant 

succession occurs. Succession is a controversial model of 

change in species composition of plant assemblages, and the 

term requires a rigorous definition (Egler, 1954; Drury and 

Nisbet 1973; Hom, 1974; White, 1979), especially when 

applied to desert plant assemblages (Muller, 1940; Shreve, 

1942; Pianka, 1974; Beatley, 1976; Rowlands, 1980). The 

arguments against the occurrence of succession in deserts are 

based either on confusion over differing definitions of what 

succession is or on what the driving forces behind vegetation 

change are. Most plant ecologists agree that "informally" 

(Pickett, 1976, p. 107) or in the "widest sense" (Drury and 

Nisbet, 1973, p. 331) succession implies change in the 

composition of a vegetation assemblage after a natural or 

human-induced disturbance. This definition is well established and does not require specification of autogenic or allogenic forces (Drury and Nisbet, 1973, p. 357; Connell, 

1980). 

We use the term "succession" to depict sequential, directional changes in the species composition of a vegetation assemblage with time. "Primary succession" refers to species 

composition changes with time occurring on newly created 

surfaces, where the effect of residuals (MacMahon, 1980) is 

negligible. "Secondary succession" refers to species composition changes with time occurring on denuded surfaces, 

where the effect of residuals (including soils) is not negligible. 

Secondary succession is distinguished from simple 

revegetation by the requirement that a species composition 

change must occur. "Simple revegetation" occurs when the 

colonizers have exactly the same species composition as the 

predisturbance vegetation. 

Primary Succession in Death Valley 

The spatial distributions of vegetation on alluvial surfaces 

in Wood Canyon and Gold Valley are inferred to represent 

primary succession sequences. The geomorphic processes 

responsible for the debris flows and the alluvial terraces 

destroyed preexisting plants and removed residual seeds and 

organic materials. In order to establish the primary succession 

sequence, spatially distributed plant assemblages were 

converted into a hypothetical assemblage that has undergone 

species composition change with time. Geomorphic processes 

will continue to episodical! y destroy patches of vegetation and 

provide new surfaces for succession to begin again. 

Soil chronosequences were used to establish a temporal 

framework for spatially distributed plant assemblages. Soils 

forming in arid climates have morphological characteristics 

that can be used as a basis for relative age dating. The 

characteristics used as the basis for our chronosequences were 

desert pavement and varnish, degree of development of B 

horizons, and degree of development of carbonate horizons. 

Use of these characteristics allows a distinction of the relative 

ages for deposits (Bull, 197 5; Gile and others, 1981; Hunt and 

Mabey, 1966), although absolute ages can only be determined 

from radiometric dating or estimated from correlation with 

areas that have been radiometrically dated. 

Soil chronosequences represent a relative time scale by 

which the development of vegetation assemblages seen on 

different surfaces can be linked to discrete times. The 

processes creating the surfaces, particularly debris flows, are 

discrete events that leave a deposit that is stable until the next 

geomorphic event. Consequently, the amount of time since the 

deposit was formed represents the time over which the 

assemblage occupying it has developed. Hence, spatial 

patterns viewed on alluvial fans can be translated into temporal 

sequences if a chronosequence can be established. 

Four primary succession sequences were developed in 

plant assemblages that are representative of the vegetation 

found between 1 ,000 and 2,000 m elevation in Death Valley 

National Monument (table 39). We use the term "assemblage" 

to reflect the dominant perennial species, with dominance 

based on the contribution of the species to ground cover. In 

Wood Canyon, young debris flows originating in granite were 

colonized by species such as Lupinus, Atriplex, and 

Penstemon sp. that were not found on older flows. The 

assemblages found on flows with increasing age were 

dominated by Ephedra, Lycium, and Grayia; Coleogyne and 

Ephedra; and Coleogyne, respectively. Another sequence of 

debris flows originating from the Kingston Peak(?) Formation 

showed a succession from an assemblage dominated by 

Acamptopappus, Grayia, and Lycium to an assemblage 

dominated by Coleogyne, Lycium, and Ephedra; a wash near 

these debris flows was lined with Hymenoclea, 

Chrysothamnus viscidiflorus, and Gutierrezia microcephala. 

In Gold Valley, Hymenoclea dominates the assemblages 

found in drainages that are infrequently scoured by floods 

(table 39). The assemblages found on terraces of increasing 

age in the lower part of Gold Valley were dominated by Larrea 

and Ephedra; Ambrosia, Lycium, and Larrea; and Ambrosia 

and Larrea. The assemblages found on terraces of increasing 

age near Gold Valley townsite were dominated by Grayia, 

A Model of Succession in Death Valley 57 
Coleogyne, and Lycium; Ephedra, Coleogyne, and Lycium; 

and Coleogvne and Larrea. The Wood Canyon and Gold 

Valley plant assemblages are compared in table 39 on the basis 

of carbonate morphology of soils, the best indicator of relative 

age, and an estimated geologic age. 

Primary succession in Death Valley follows a pattern best 

described using life-history strategies. Species with a high 

emphasis on reproduction and growth and a low emphasis on 

longevity (for example, Hymenoclea, Chrysothamnus) are the 

dominants in the colonizing stage. These species are replaced 

by an intermediate group with a wide range in characteristics, 

but generally have a lower reproductive ability, slower growth, 

and longer lifespans than the colonizers. With increasing time, 

species that have lowest reproductive ability, slowest growth, 

and longest lifespans (for example, Larrea, Coleogyne) 

dominate. 

Recovery of Soil Properties and Revegetation of 

Abandoned Townsites 

Five abandoned townsites and the Skidoo pipeline 

corridor were measured to determine the recovery of soil 

properties and vegetation assemblages from human 

disturbances. Soil compaction was measured to test the 

hypothesis that compaction would retard the revegetation of 

townsites. Compaction was present in all but one site; the 

exception (Greenwater townsite B) probably was not occupied 

to the same extent as the other sites. 

Recovery times were estimated using a linear model of the 

change in soil physical properties with iime. This model was 

used instead of a more realistic exponential-decay model 

(Webb and Wilshire, 1979) because the properties at only three 

points in time-represented by active roads, abandoned sites, 

and undisturbed sites-could be compared. This model would 

be expected to predict minimum recovery times, because the 

rate of change of soil properties . decreases as the soil 

approaches total recovery. The predicted recovery times range 

from 80 to 120 yr (table 40), and given the uncertainties 

involved in these predictions, soil compaction in the townsites 

requires on the order of a century (±50 yr) for total 

amelioration. Compaction does not appear to be a factor 

affecting revegetation, because few differences between the 

vegetation in compacted and that in noncompacted sites could 

not be attributed to natural variability. 

Vegetation assemblages in the townsites were distinctly 

different from those in the control sites (table 41). Hymenoclea, Stipa, or Ephedra were the dominants in the four townsites in which Larrea was present; Larrea, Lycium, Coleogyne, 

Menodora, or Grayia dominated the corresponding control 

sites. At Skidoo, Grayia was the dominant in both control and 

disturbed sites; consequently, it appears that Skidoo has 

recovered to a greater extent than the areas dominated by 

Larrea. However, Grayia contributed less cover in disturbed 

sites than in control sites at Skidoo, and Chrysothamnus 

appeared to be an important colonizer there. 

Unlike the townsites, the assemblages found in the Skidoo 

pipeline corridor were not always distinctly different from the 

adjacent control assemblages (table 42). The greatest 

differences between pipeline corridor segments and adjacent 

controls were in the absolute cover contribution of the 

dominants and in the abundance of species like 

Chrysothamnus in the pipeline corridor. For example, the 

Harrisburg Flats pipeline corridor and control were both 

dominated by Chrysothamnus and Qrnvia (table 42), but the 

pipeline corridor had 4.5 percent more cover of 

Chrysothamnus and 4.0 percent less cover ofGrayia than did 

the control (table 15). In addition, Atriplex canescens 

contributed 1.4 percent cover in the pipeline corridor, but only 

0.3 percent cover in the control. Similar differences were 

observed in other segments of the pipeline corridor, and the 

differences were large enough that the pipeline corridor was 

still conspicuous from a distance in 1981 (figs. 8, 13, 14). 

Differences appeared to depend somewhat on the length of 

time since the corridor was dismantled; for example, the 

segment at Nemo Crest (dismantled in 1938) has not recovered 

to the extent of the segments in Wood Canyon (dismantled in 

1917) despite the close proximity and similarity of undisturbed 

vegetation. Moreover, the difference between the recoveries of 

the Wildrose Canyon segments C and Dis marked (table 20); 

segment C was dismantled in 1938, whereas segment D has 

been left intact since 1906. 

Ordinations 

Four ordinations using Wisconsin polar ordination and 

principal-components analysis were generated for town sites in 

Larrea-dominated assemblages (figs. 34, 35). The two 

ordination methods were used because Wisconsin polar 

ordination is more subjective but creates less distortion in 

ordination graphs than does principal-components analysis. 

Data from Webb and Wilshire (1979) for the Wahmonie 

townsite were combined with the data from Greenwater, 

Kunze, Furnace, and Gold Valley townsites. In general, both 

methods produced a clear separation among control and 

disturbed sites. In the ordinations based on cover (fig. 34 ), the 

eastern townsite at Gold Valley, the least disturbed of all sites 

studied, was the only disturbed site not clearly separated from 

the cluster of control sites. However, the correlation 

coefficient and PS value between the eastern townsite and the 

nearest similar control site were only 0.29 and 37.8 percent, 

respectively, on the basis of cover (table 43). Correlation 

coefficients and PS values greater than 0.60 and 70 percent, 

respectively, indicate similar vegetation assemblages (see 

section on "Reproducibility and Spatial Variability"). The 

percentages of total variance explained in the principalcomponents analyses were 59 and 65 percent for the cover (fig. 

34A) and density (fig. 35A) ordinations, respectively. The 

variance explained for each site appears in table 44. 

Ordinations using Wisconsin polar ordination and principal-components analysis with cover data were also generated for sites in the Panamint Range (fig. 36). The separation 

58 Response of Vegetation to Disturbance, Death Valley National Monument, California 
3 

A 

2 

y 1 

3 10 

0 

-1 

0 3 4 

60.0r--------------.--------------.--------------.,--------------r--------------, 

45.0 

y 

30.0 

B 

X 

Figure 34. Ordination graphs based on plant cover at town sites in Larrea-dom ina ted assemblages. Dark squares 

represent disturbance sites; light squares represent corresponding control sites. Site numbers are listed in table 

43. A, Principal-components solution. B, Wisconsin polar ordination solution. 

A Model of Succession in Death Valley 59 
36.--------------.--------------,---------------.--------------.--------------, 

A 19 

16 

27 

y 18 7 

13 

9 

o<: 15 

18 3~~2~ 5 1 

0 L_ ____________ _L ____________ ~--------------~------------~------------~ 

0 10 20 30 40 50 

65.0r-------------~--------------~--------------.--------------.--------------, 

50.0 

8 

35.0 

14 

y 

20.0 

5.0 

16 -10. OOL. 0--------------2.L0-.0-------------4_J0_.0 ______________ 60L.-0 -------------8...1..0-.0-------------:-1 0~0.0 

X 

Figure 35. Ordination graphs based on plant densities at townsites in Larrea-dominated assemblages. Dark 

squares represent disturbed sites; I ight squares represent corresponding control sites. Site numbers are listed in 

table 43. A, Principal-components solution. 8, Wisconsin polar ordination solution. 

60 Response of Vegetation to Disturbance, Death Valley National Monument, California 
between control and disturbed sites is not clear in these graphs 

as a result oflarge environmental gradients; assemblages range 

from Grayia-dominated to Artemisia tridentata-dominated 

(with Pinus and Juninerus). The principal-components 

solution first axis (X) apparently reflects variability resulting 

from disturbance, whereas the second axis (Y) apparently 

reflects variability resulting from environmental gradients. 

The assemblages represented change in composition from 

.Qravia-Eohedra-dominated to Coleogyne-dominated to 

Artemisia-Coleogvne-dominated from bottom to top in the 

principal-components ordination (fig. 36). The correlation 

coefficients (table 45) indicate that the assemblages at Skidoo, 

Harrisburg Flats, and Wood Canyon are unrelated to those in 

Wildrose Canyon; this is reflected in the clustering patterns 

shown in figure 36A. Only 48 percent of the total variance is 

explained by the first two axes, and the variance explained for 

individual sites (table 46) suggests that addition of a third axis 

would improve the distinctions. 

Comparisons and Contrasts Between Primary and 

Secondary Succession 

The primary succession sequences provide a framework 

for predicting future changes in vegetation assemblages in the 

townsites. The stage of primary succession at a given site 

appears to be related to the degree of soil development, which 

is a function of time. Primary succession in assemblages other 

than those studied can be assumed to be qualitatively similar to 

the primary succession sequences in Wood Canyon and Gold 

Valley, given comparable environmental settings. 

Revegetation of abandoned townsites, when viewed in the 

context of primary succession sequences, appears to represent 

the first stage of secondary succession. The species colonizing 

townsites-especially Hymenoclea and Chrysothamnus 

viscidiflorus-are also the colonizers in primary succession 

sequences. Moreover, the occurrence of species in townsites 

(table 41) are in general agreement with the sequences of 

primary succession (table 42). Therefore, secondary 

succession appears to be a viable model for the process of 

revegetation and can be used to describe the rate of recovery. 

Application of primary and secondary succession models 

helps to explain variability in the patterns observed in Skidoo 

and along the Skidoo pipeline corridor. Skidoo townsite and 

many segments of the Skidoo pipeline corridor have 

comparable environmental settings with the debris flows in 

Wood Canyon. At Skidoo, the granitic alluvial substrate with 

a weak stage I carbonate horizon (table 10) supports an 

undisturbed assemblage dominated by .Qravia, Ephedra, and 

Artemisia. At Wood Canyon, debris flows 2 and B, with a 

comparable parent material and soil morphology (compare 

tables 6 and 10), support assemblages generally dominated by 

a combination of Acamptopappus, Lycium, Qrsvig, and 

Ephedra. Coleogyne, abundant on hillslopes around Skidoo, is 

not present in either the disturbed or control sites at Skidoo. 

This finding suggests that the undisturbed vegetation at Skidoo 

is in an early primary succession stage, and it also could explain 

the fast recovery of Skidoo when compared with other 

townsites. 

The assemblages found at Harrisburg Flats can be 

similarly compared. The substrate at Harrisburg Flats lies on 

a low slope and occasionally is flooded, which indicates both 

a young geologic age and an adaptation of the vegetation 

assemblages to periodic disturbances. Coleogyne is present on 

hillslopes surrounding the Flats. The undisturbed vegetation 

assemblage is dominated by Grayia and is also comparable 

with debris flows 2 and B in the primary succession sequence 

observed in Wood Canyon. Similar arguments can be 

developed to compare the undisturbed assemblages at Nemo 

Crest and Wildrose Canyon (segment A) with debris flows 3, 

A, and C. 

A general trend was observed in the comparison of 

primary and secondary succession sequences in the Panamint 

Range. Recovery of vegetation on disturbed sites depends on 

the age of the geomorphic surface and thus on the stage of 

primary succession of the undisturbed vegetation. For 

example, all the sites at Skidoo and at Harrisburg Flats plot in 

close proximity on the ordination graphs (fig. 36), and the 

correlation coefficients between disturbed and control sites at 

Skidoo and Harrisburg Flats average 0.85. In contrast, 

recovery appears to require much longer timespans on older 

surfaces because differences in vegetation assemblages are 

greater between disturbed and undisturbed sites where soils are 

better developed. The correlation coefficients between 

disturbed and control sites are 0.41 for Wood Canyon flow A, 

0.68 for Wood Canyon flow B, 0.85 for Wood Canyon flow C, 

and average 0.34 for the two disturbed-control comparisons at 

Nemo Crest. Wood Canyon flow C would be expected to have 

a similar correlation coefficient to flow A, based on the similar 

ages of these flows; this anomaly could, in part, result from the 

lesser disturbance of vegetation resulting from emplacement 

of an aboveground pipeline. 

Similar comparisons could not be performed using the 

ordinations for townsites with Larrea. Disturbed sites were 

generally devoid of Larrea, and more than a few scattered 

individuals would be expected in disturbed sites given the 

appearance of Larrea in the early primary succession stages in 

Gold Valley. Townsites with Larrea in the surrounding 

vegetation were built near the upper elevation limit for this 

species, and germination and survival of Larrea would be 

expected to be affected by climatic fluctuations. Hence, the 

climatic shift responsible for the changes recorded in packrat 

middens could be responsible for the low amount of 

germination of Larrea in townsites. Consequently, correlation 

coefficients between disturbed and control sites in these 

townsites would be expected to be consistently higher if the 

town sites studied were well below the upper elevation limit of 

Larrea. 

A Model of Succession in Death Valley 61 
y 

A 

24 

4 

3 

22 

25 

y 

0 

3~1 

0~4 

-1 ~------~~------~--------~--------~--------~--------~--------~--------~ 

0 3 4 5 6 7 8 

100.0 r--------------,,--------------.---------------,--------------~--------------~ 

B 19 

60.0 

24 

40.0 

14 

20.0 6 

4 

0.0 ~------------~~------------~~~----------~--------------~--------------~ 

0.0 20.0 60.0 80.0 100.0 

X 

Figure 36. Ordination graphs based on plant cover at sites in the Panamint Range. Dark squares represent 

disturbed sites; light squares represent corresponding control sites. Site numbers are listed in table 45. A, 

Principal-components solution. B, Wisconsin polar ordination solution. 

62 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Life-History Strategies and Succession 

The pattern present in the successional sequences can be 

interpreted using the life-history strategies of Grime ( 1979; see 

section on "Life-History Strategies"). However, this approach 

involves a degree of circular reasoning because independent 

life-history strategy data are scarce for most Mojave Desert 

species, and thus classification for these species relies heavily 

on their behavior in disturbed areas. Based on published 

literature, Larrea and Hymenoclea are archetypal stress 

tolerators and stress-tolerant ruderals, respectively. The 

successions in all areas begin with Hymenoclea or other 

species with apparently similar strategies (for example, 

Lupinus, Chrvsothamnus sp.). Grayia, Lycium, and Ephedra 

eventually dominate, with Coleogyne and Larrea of 

importance locally. Coleogyne and (or) Larrea eventually 

become dominant, with Ambrosia dominating at lower 

(<1,300 m) elevations. Succession in Death Valley could be 

viewed as temporal changes in the life-history strategies of the 

dominants from stress-tolerant ruderals to stress-tolerant 

competitors to stress tolerators. 

Not surprisingly, this pattern is similar to the model 

proposed by Grime ( 1979) for "unproductive habitats." Until 

further life-history strategy data are collected to allow for an 

independent classification, this apparent support for Grime's 

model should be considered tentative. The use of Grime's 

classification framework to describe succession in different 

assemblages is limited by the difficulty in grouping life-history 

strategies unique to each species and by possible ecotypic 

variation. For example, species such as Ambrosia and 

Coleogyne do not possess all the characteristics of stress 

tolerators (table 1) but assume dominance on the oldest 

surfaces; similarly, the occurrence of Ephedra and 

Haplopappus in successions is not consistent in all sites (table 

41). However, Grime's approach is useful for regional 

comparisons of succession because it accounts for 

physiological and reproductive characteristics and allows a 

finer resolution to strategy type than do other frameworks. 

The classification of a species according to Grime's 

approach requires a balance between the generalization 

necessary to group different ecotypes within a species and the 

resolution necessary to group different species into a particular 

strategy. This balance may be achieved by ranking the 

attributes that are most important in a given succession (Noble 

and Slayter, 1980). In plant successions in Death Valley, 

species with relatively high growth rates and reproductive 

capacity are most important in colonization, whereas species 

that emphasize maintenance of individuals at the expense of 

reproduction (leading to extreme longevity with few 

replacements) and greater adaptation to environmental stress 

are most important as the succession progresses. 

The Forces Behind Succession in Death Valley 

A combination of allogenic and autogenic forces cause 

succession in Death Valley, and their relative importance 

varies as the succession progresses. In any seedling 

establishment, there is a change in microenvironment that may 

or may not be beneficial to germination and survival 

(McCormick, 1968, p. 9). Pioneering species may actually 

create a more hostile environment for successive species 

(Drury and Nisbet, 1973; Connell and Slayter, 1977; Connell, 

1980). However, the majority of changes occurring on a newly 

created surface must be beneficial to species in subsequent 

successional stages. Nutrient additions and concentration in 

the soil (Garcia-Moya and McKell, 1970), reduction in 

evaporation around shrubs (Wallace and others, 1980), and 

even shading and frost protection for seedlings (Turner and 

others, 1966) are examples of beneficial changes. Therefore 

autogenesis, often denied in desert plant assemblages (Shreve, 

1942; Rowlands and Adams, 1980), is an important force 

behind succession. 

Autogenic factors in Death Valley plant assemblages are 

most important in the colonization stage because the species 

composition changes through several stages in the absence of 

significant pedogenesis. After creation of a new substrate, 

stress-tolerant ruderals such as Hymenoclea and 

Chrysothamnus are the first species to be established. With 

increasing time, individuals of species such as Ephedra or 

Acamptopappus become established that apparently outlive 

the initial colonizers. Competitive interactions and, to a 

limited extent, site modifications are probably the most 

important forces in these initial stages. Stress tolerators such 

as Larrea and Coleogyne assume dominance through 

competitive superiority, which is manifested as the soil 

develops. 

The forces behind secondary succession appear to be 

primarily autogenic given the slow rate of soil formation in 

deserts. Depending on the degree of disturbance, the first 

plants to colonize a barren site will be either colonizers from 

the surrounding vegetation, species germinating from the 

surviving seedbank, and (or) individuals regenerated by rootcrown sprouting. Stress-tolerantruderals, especially those that 

produce large numbers of seeds and have highly efficient 

dispersal mechanisms, will colonize a disturbed site despite the 

existing seedbank and control soil moisture (Wallace and 

others, 1980). Colonization from the existing seedbank will 

favor species occupying the site prior to disturbance, but such 

colonization requires minimal soil disruption. In sites without 

significant disturbance of the soil, root-crown sprouting, 

which occurs for many common Mojave and Great Basin 

Desert species, may be the dominant form of revegetation. 

The importance of seedbank revegetation and root-crown 

sprouting depends on the composition of the predisturbance 

vegetation, which in tum depends on the site's primary 

succession stage. In the townsites, blading and compaction 

appeared to destroy most root-crowns, and thus some 

combination of seedbank revegetation and invasion 

revegetation resulted, depending primarily on the life-history 

strategies of the species and the degree of disturbance. 

Autogenic forces such as competition become less 

important with increasing time. The stress caused by the arid 

A Model of Succession in Death Valley 63 
climate is continuous and does not decrease as succession 

proceeds. Nutrient additions are offset by withdrawals and are 

limited by the potential productivity of litterfall at a site. 

Although moisture loss through evaporation on a barren 

surface would be expected to be high, the level of moisture may 

not increase once shade is provided because of transpiration by 

colonizers. Available moisture thus decreases as a surface 

becomes colonized, and competition for the moisture, severe 

in the initial stages, slows as species which are competitively 

superior and longer lived gain dominance (Wallace and others, 

1980). 

Allogenic processes become more important in the later 

stages of succession. The probability of severe disturbances, 

such as floods or debris flows, increases with time. 

Accumulating quantities of carbonate and clay in soils change 

the soil chemistry and water-retention capacity. With 

substantial time, stage IV carbonate horizons develop that limit 

root growth and alter soil hydrologic properties. Climate 

changes such as the Pleistocene-Holocene change can 

completely alter the species composition of a site, and the 

occurrence of climatic fluctuations may alter successional sequences if the important species are near environmental limits. 

In addition to the successional changes occurring on a 

newly created substrate, other environmental factors also 

cause vegetation change, and these factors may account for 

discrepancies in our model. Geomorphic processes such as 

episodic erosion or deposition; evolutionary changes, as 

exemplified by ecotypic variation; the natural disturbance 

regime, such as periodic fire or grazing; climatic fluctuations; 

and human influence have all significantly affected the 

vegetation patterns present today. Each geomorphic surface 

formed at a discrete time, and each vegetation assemblage has 

its own history of change in which succession is the major part. 

The process of recovery is linked with the history of the 

ambient vegetation assemblages. Comparison of a recovering 

vegetation assemblage to the predisturbance assemblage 

would be meaningless if some environmental factor were to 

cause widespread change. Also, primary succession continues 

as recovery progresses, which again leads to change from 

predisturbance conditions. Therefore, a definition of when a 

disturbed site is recovered must use ambient, not 

predisturbance, vegetation assemblages as its basis. 

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References Cited 69 

TABLES 1-47 

Table 1. Application of the life-history classification framework of Grime (1979) to desert species 

[Based on Grime, 1979, table 6, p. 48-49] 

Longevity 

Growth form 

Leaves: 

Production time 

Longevity 

Morphology 

Palatability 

Reproduction: 

Phenology of 

flowering 

Seed production 

Regeneration 

strategy 

Physiology: 

Growth rate 

Proportion of 

production 

devoted to 

reproduction 

Stress tolerators 

Long-lived 

Shrubs and 

trees 

Favorable conditions 

Evergreen or xerophytic deciduous 

Small 1 eathery, needle1 ike, xerophytic 

Low 

Flowers whenever 

conditions are favorable 

Small 

Expansion from root 

crown; persistent 

seedling bank 

Slow 

Low 

Criteria for classification 

Stress-tal erant 

competitors 

Long--to short-lived 

Shrubs and 

trees 

Mainly seasonal 

Deciduous 

Small to relatively 

large, xerophytic 

Low to high 

Mainly seasonal 

Small 

Expansion from root 

crown; persistent 

seedling hank 

Slow to intermediate 

Low 

Stress-tal erant 

ruderal s 

Short-1 i ved 

Shrubs to 

subshrubs 

Seasonal 

Deciduous 

Varies 

Low to high 

Mainly seasonal 

Large 

Persistent seed 

and seedling hank 

Fast 

Medium to high 

Ruderal s 

Annuals 

Herbs 

Seasonal 

Deciduous 

Varies; often 

mesomorphic 

Often high 

Seasonal 

Large 

Persistent seed 

bank 

Fast 

High 

Tentative life-history classification of selected Mojave Desert species 

Artemisia tridentata 

Coleogyne ramosissima 

Juniperus osteosperma 

Larrea tridentata 

Pinus monophylla 

Acamptopappus shockley; 

Ambrosia dumosa 

Grayia spinosa 

Ephedra nevarlensis 

Lycium andersonii 

Tetradymi a sp. 

Atriplex canescens Ch rysothamnus nauseosus Chrysothamnus viscidiflorus 

E ri ogonum i nfl atu!Tl 

Eriogonum fasciculatum 

Gutierrezia microcephala 

Haplopappus cooperi 

Hymenoclea salsola 

Oryzopsis hymenoides 

Salazaria mexicana 

Stipa speciosa 

Thamnosma montana 

Bromus rubens 

Eriogonum sp. 

Erodium cicutarium 

Salsola iberica 

Tables 73 
Table 2. Regression coefficients of dry-weight biomass for Mojave Desert shrubs 

[Values are in kilograms per cubic meter. NTS, Nevada Test Site (R.B. Hunter, 

written commun., 1981). Values are ±1 standard error of the mean. COCA, 

California Desert Conservation Area {P.G. Rowland, written commun., 1981). 

e, estimated. The number of shrubs sampled was much smaller for the COCA 

coefficients. Additional information and data are contained in Wallace and 

Romney {1972, p. 251-252)] 

Species NTS COCA 

Acam~to~a~~us shocklexi 3.1 ± 0.2 2.8 

Artemisia s~inescens 4.1 ± 0.2 4.0 

Artemisia tridentata 1.8 ± 0.1 1.8 

Chrxsothamnus viscidiflorus 3.2 ± 0.2 3. 3e 

Coleogyne ramosissima 5.2 ± 0.3 4.8 E~hedra nevadensis 1.4 ± 0.2 4.3 

Graxia s~inosa 2.3 ± 0.1 4.3 Ha~lo~a~~us coo~eri 3.2 ± 0.4 2.8 

Hxmenoclea salsola 3.2 ± 0.2 1.5 

Carrea tridentata 1.3 ± 0.1 2.1 

Lxcium andersonii 2.2 ± 0.1 2.0 

Menodora s~inescens 8.3 ± 0.5 8.4 Orxzo~sis hxmenoides 1.1 ± 0.3 2.5 Sti~a s~eciosa 1.1 ± 0.3 2.9 

Thamnosma montana 1.7 ± 0.1 3.0 

Table 3. Density and cover of perennial vegetation as field tested in Gold Valley, showing variability by different operators viewing 

transects fixed. by each operator 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean] 

Operator--------------

Species 

Shrubs: 

Grayi a s pi nos a Larrea tridentata 

Thamnosma montana 

Ephedra nevadensis 

Lycium andersonii 

Salazaria mexicana 

Acamptopappus shockleyi 

Hymenoclea salsola 

Ambrosia dumosa 

Haplopappus cooperi 

Tetradymia spinosa 

Subtotal 

Herbaceous perennials: 

Mirabilis bigelovii 

Dyssodia cooperi 

Eriogonum inflatum 

Subtotal 

Grass: 

Stipa speciosa 

Total live 

Dead 

Total 

Density 

1,500 ± 

300 ± 

500 ± 

1,200 ± 

500 ± 

700 ± 

1,300 ± 

400 ± 

200 ± 

100 ± 

0 

100 

100 

200 

300 

0 

200 

500 

200 

100 

0 

A 

Cover 

5.6 ± 1.0 

5.3 ± 1.0 

2.5 ± 1.0 

2.4 ± 0.7 

1.8 ± 0.4 

1.5 ± 0.5 

1.3 ± 0.5 

0.2 ± 0.1 

0.2 ± 0.1 

0.1 ± 0.1 

0.1 ± 0.1 

6,700 ± 700 21.0 ± 2.0 

300 ± 

100 ± 

200 ± 

600 ± 

100 

0 

200 

300 

2,100 ± 600 

0.1 ± 0.1 

o.o 

o.o 

0.1 ± 0.1 

1.8 ± 0.4 

9,400 ± 1,000 22.9 ± 2.1 

400 ± 200 2.9 ± 0.6 

9,800 ± 1,100 25.8 ± 2.3 

Density 

1,400 ± 100 

300 ± 0 

500 ± 200 

1,000 ± 300 

400 ± 100 

500 ± 100 

1,200 ± 400 

300 ± 100 

100 ± 100 

100 ± 0 

0 

5,800 ± 600 

100 ± 100 

100 ± 100 

400 ± 400 

600 ± 400 

1,900 ± 500 

8,300 ± 900 

600 ± 100 

8,900 ± 900 

B 

Cover 

7.0 ± 1.4 

5.6 ± 1.1 

2.7 ± 1.0 

3.5 ± 0.9 

2.5 ± 0.6 

1.5 ± 0.5 

1.4 ± 0.7 

0.2 ± 0.1 

0.1 ± 0.1 

o.o 

o.o 

24.5 ± 2.5 

0.1 ± 0.1 

o.o 

o.o 

0.1 ± 0.1 

2.1 ± 0.5 

26.7 ± 2.5 

1.6 ± 0.4 

28.3 ± 2.6 

74 Response of Vegetation to Disturbance, Death Valley National Monument, California 

Density 

1,400 ± 

300 ± 

500 ± 

1,000 ± 

500 ± 

600 ± 

1,200 ± 

300 ± 

100 ± 

200 ± 

100 ± 

100 

100 

200 

300 

100 

200 

500 

100 

100 

100 

100 

c 

Cover 

5.8 ± 1.3 

5.9 ± 1.1 

2.7 ± 1.0 

2.9 ± 0.7 

1.9 ± 0.3 

1.2 ± 0.6 

1.2 ± 0.6 

0.3 ± 0.1 

0.1 ± 0.1 

o.o 

0.1 ± 0.1 

6,200 ± 700 22.1 ± 2.2 

100 ± 100 

100 ± 100 

500 ± 400 

700 ± 400 

0.1 ± 0.1 

o.o 

0.1 ± 0.1 

0.2 ± 0.1 

2,400 ± 500 3.3 ± 0.7 

9,300 ± 900 25.6 ± 2.4 

1,000 ± 100 3.0 ± 0.4 

10,300 ± 1,000 28.6 ± 2.4 
Table 4. Density and cover of perennial vegetation as field tested in Gold Valley showing variability by different operators viewing the same 

transect 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean] 

Operator --------------- A B 

Species Density Cover Density Cover Density 

Shrubs: 

H~menoclea salsola 6,000 ± 600 10.4 ± 1.6 5,700 ± 600 11.6 ± 1.8 5,500 ± 700 

Eehedra nevadensis 2,900 ± 500 5.4 ± 1.0 2,900 ± 600 6.6 ± 1.0 3,100 ± 400 Gra~ i a s ei nos a 800 ± 200 2.9 ± 0.7 800 ± 200 3.2 ± 0.7 800 ± 200 L~cium andersonii 300 ± 100 2.4 ± 0.8 300 ± 100 2.3 ± 0.8 400 ± 100 

Thamnosma montana 500 ± 100 2.1 ± 0.5 500 ± 100 2.2 ± 0.5 600 ± 200 

Erio9onum fasciculatum 600 ± 200 1.8 ± 0.6 500 ± 200 1.7 ± 0.7 600 ± 200 Tetrad~mia stenoleesis 100 ± 0 0.6 ± 0.4 100 ± 100 0.8 ± 0.4 100 ± 0 

Ambrosia dumosa 300 ± 200 0.5 ± 0.2 400 ± 300 0.5 ± 0.3 300 ± 200 

Dalea fremontii 100 ± 0 0.3 ± 0.2 lOU ± 0 0.3 ± 0.2 100 ± 0 

Salazaria mexicana 100 ± 100 0.2 ± 0.2 100 ± 100 0.2 ± 0.2 100 ± 100 

Larrea tridentata 0 0.1 ± 0.1 0 0.1 ± 0.1 0 

Haeloeaeeus cooperi 0 0.1 ± 0.1 0 0.1 ± 0.1 0 

Subtotal 11,700 ± 900 26.8 ± 2.6 11,400 ± 1,000 29.6 ± 2.5 11,600 ± 900 

Herbaceous perennials: 

Sehaeralcea ambi9ua 400 ± 200 0.2 ± 0.2 400 ± 200 0.2 ± 0.2 400 ± 200 

Erio9onum inflatum 2,900 ± 700 0.2 ± 0.1 3,400 ± 800 0.1 ± 0.1 4,100 ± 900 D~ssodia cooeeri 300 ± 200 o.o 300 ± 100 o.o 300 ± 100 

Castilleja chromosa 100 ± 100 o.o 200 ± 100 o.o 300 ± 200 

Machaeranthera tortifolia 100 ± 100 0.0 100 ± 100 0.0 100 ± 100 

Mirabilis bi9elovii 100 ± 100 0.1 ± 0.1 100 ± 100 o.o 100 ± 0 

Subtotal 3,900 ± 800 0.5 ± 0.3 4,500 ± 800 0.3 ± 0.2 5,300 ± 1,000 

Grass: 

Stiea seeciosa 600 ± 300 0.2 ± 0.2 600 ± 400 0.1 ± 0.1 900 ± 400 

Total 1 i ve 16,200 ± 1,200 27.5 ± 2.6 16,500 ± 1,300 29.9 ± 2.6 17,800 ± 1,400 

Dead 2,400 ± 300 5.1 ± 0.4 1,800 ± 200 4.3 ± 0.5 2,700 ± 200 

Total 18,600 ± 1,200 32.6 ± 2.6 18,300 ± 1,400 34.2 ± 2.6 20,500 ± 1,400 

Table 5. Comparison of vegetation data from Wahmonie townsite and control 

areas 

[Data from Webb and Wilshire (1979) and Beatley {1979, 1980)] 

Site Percent similarity 

2 3 4 5 6 7 

1 46 33 38 34 32 33 

2 34 23 14 70 80 80 

3 49 7 19 28 14 13 

4 70 2 28 14 4 5 

5 29 84 4 2 54 57 

6 15 94 7 -25 62 90 

7 -12 97 5 -26 84 96 

1. Streets and avenues (Webb and Wilshire, 1979, p. 297). 

2. Southwest control (Webb and Wilshire, 1979, p. 297). 

3. Old Main Road (Webb and Wilshire, 1979, p. 299). 

4. Townsite (Webb and Wilshire, 1979, p. 299). 

5. Northeastern Control {Webb and Wilshire, 1979, p. 299). 

6. Site 66 {Southwest Control), 1963 (Beatley, 1979; 1980, 

p. 157-158). 

7. Site 66 (Southwest Control), 1975 (Beatley, 1979; 1980, 

p. 157-158). 

c 

Cover 

12.0 ± 1.8 

7.5 ± 1.7 

3.3 ± 0.8 

2.5 ± 0.9 

2.1 ± 0.5 

2.0 ± 0.7 

0.9 ± 0.5 

0.5 ± 0.3 

0.3 ± 0.2 

0.2 ± 0.2 

0.1 ± 0.1 

0.1 ± 0.1 

31.5 ± 3.0 

0.3 ± 0.1 

0.2 ± 0.1 

o.o 

o.o 

o.o 

0.1 ± 0.1 

0.6 ± 0.2 

0.3 ± 0.1 

32.4 ± 3.0 

4.4 ± 0.6 

36.8 ± 3.0 

Tables 75 
Table 6. Soil and site descriptions for debris flows in Wood 

Canyon 

[Abbreviations used: Texture: k, cobbly; g, gravelly; ls, loamy sand; 

sl, sandy loam; s, sand; scl, sandy clay loam. Color: Munsell notation 

(hue value/chroma). Carbonate: Stages follow nomenclature of Gile and 

others (1981, p. 67). See Soi 1 Survey Staff (1975) for further detai 1 s] 

Debris flow 1 

Age: 5 yr 

Source material: cobbles and grus of granite 

Exposure and elevat1on: 8-10° WNW., 1,750 m 

Number of descriptions: 2 

Depth (em) 

0-7 

7 -50+ 

Horizon --AC 

Texture 

I<9TS 

kgl s 

Dry color 

10 YR 6/3 

10 YR 6/3 

Debris flow 2 

Estimated Age: late Holocene 

Carbonate 

Source Material: cobbles and grus of granite with minor 

metasedimentary rocks 

Exposure and elevation: 8-10° WSW., 1,750 m 

Number of descriptions: 2 

Depth (em) Horizon Texture Dr~ color 0-6 --,::- ---rgsr lO YR 5;3 

6-12 c1 kgl s 10 YR 5/3 12-25 c2 kg(s-ls) 10 YR 5/3 25-50 IIC3ca kgs 10 YR 6/3 50-65+ I IC4ca kgs 10 YR 6/3 

Debris flow 3 

Estimated Age: middle Holocene 

Source Material: cobbles and grus of granite 

Exposure and elevation: 8-10° WSW., 1,750 m 

Depth (em) 

0-5 

5-15 

15-65+ 

Horizon --AC1 

c2ca 

Texture 

---rgsrkgsl 

kgsl 

Dry color 

10 YR 5/3 

10 YR 5/3 

10 YR 6/3 

Debris flow 4 

Estimated Age: late Pleistocene 

Source Material: cobbles and grus of granite 

Exposure and elevation: 10° SW., 1,830-1,860 m 

Continuous exposure 

Depth (em) Horizon Texture Dr~ col or 0-5 --A- ---rgsr- 10 YR 6/4 

5-12 B1 kgs 1 10 YR 5/6 

12-90 I I 82tca kgl s * 7. 5 YR 5/6 

90-175 I ICc a 

*clay skins on pebbles 

Ca rhonate 

stage 

stage 

Carbonate 

stage I 

Carbonate 

stage I 

stage I 

stage I 

stage III 

Exposed profile in wash in Wood Canyon 

Source Materials: granitic and metasedimentary rocks 

Exposure and elevation: 2° W., 1,720 m 

Continuous exposure 

Depth (em) Horizon Texture Dr~ Color 

0-5 --A- _g_l_s_ 10 YR 5/3 

5-15 ~lea gl s 10 YR 5/3 

15-36 kgsl 10 YR 5/3 

36-63 I IC~~~ kl s 10 YR 5/3 

63-98 I I IC4ca kl s 10 YR 6/4 

98-115 I VC5ca ks 10 YR 6/4 

115-143 I VC6ca kl s 10 YR 6/4 

143-173 VBtb gs 1 7. 5 YR 5/6 17 3-230+ VCcab 

Carbonate 

stage I 

stage I 

stage II 

stage II 

stage II 

stage II 

stage IV 

Table 6. Soil and site descriptions for debris flows in Wood 

Canyon-Continued 

Lower Wood Canyon debris flows 

Debris flow A 

Estimated Age: latest Pleistocene or early Holocene 

Source Material: metasedimentary rocks of the Kingston Peak (?) 

Formation 

Exposure and elevation: 5° N., 1,650 m 

Number of descriptions: 1 

Depth (em) Horizon Texture Dr~ color Carbonate 

0-2* ~ _k_g_ 

2-10 A12 kgs 1 10 YR 7/4 

10-45 ~2tca kgscl 7. 5 YR 6/6 stage I 

45-1 00+ kgs 1 10 YR 6/4 stage I-I I ca 

*desert pavement, well varnished 

Oebri s flow B 

Estimated Age: middle Holocene 

Source Material: metasedimentary rocks of the Kingston Peak (?) 

Formation 

Exposure and elevation: 6° NNW., 1,700 m 

Number of descriptions: 1 

Depth (em) Horizon Texture Dr~ col or 

0-2* -rill --kg- 10 YR 6/4 

2-10 A12 gsl 10 YR 6/4 

10-40 c1 kgsl 10 YR 6/4 

40-70 I IC2ca gl s 10 YR 6/3 

70-100 I IC3ca gl s 10 YR 6/3 

*desert pavement, 1 ightly varnished 

Debris flow C 

Carbonate 

stage 

stage 

stage 

Estimated Age: latest Pleistocene or early Holocene 

Source Material: metasedimentary rocks of the Kingston Peak (?) 

Formation 

Exposure and elevation: 10° NNW., 1,710 m 

Number of descriptions: 1 

Depth (em) Horizon Texture Dr~ color 

~ --kg- 0-2* 

2-10 A12 gsl 10 YR 5/3 

10-30 B21 kgscl 7 ,':, YR 5/6 

30-55 ~22ca kgsl 7. 5 YR 5/4 

55-100+ kgsl 10 YR 5/4 ca 

*desert pavement, well varnished 

Carbonate 

stage I 

stage II 

stage I-I I 

76 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 7. Density and cover of perennial vegetation on four debris flows originating in granite in eastern Wood Canyon 

[Density values, in number per hectare, were determined from four 3 X 50-m belt transects on debris flow 1 and two 3 X 50-m belt 

transects on the other flows. Individuals of certain species, particularly Ephedra on older flows, were difficult to define. 

Cover, in percent, was determined from eight 50-m line intercepts per rlehris flow, anrl the term reflects the standard error of 

the mean of these eight measurements] 

Species 

Shrubs: 

Coleogyne ramosissima 

Ephedra nevadensis 

Lycium andersonii 

Grayi a spi nos a Acamptopappus shockleyi 

Thamnosma montana 

Haplopappus cooperi 

Artemisia tridentata 

Erigonum fasciculatum 

Chrysothamnus teretifolius 

Chrysothamnus nauseosus Salazaria mexicana 

Gutierrezia microcephala 

Hymenoclea salsola 

Lupinus excubitus 

Subtotal 

Herbaceous perennials: 

Sphaeralcea rusbyi 

Astragalus lentiginosus 

Subtota 1 

Grasses~ 

Others 

Dead 

Total live 

Total 

0 

0 

100 

300 

100 

0 

0 

100 

100 

0 

300 

0 

200 

0 

100 

1,300 

200 

600 

800 

300 

100 

2,500 

300 

2,800 

Density 

2 3 

2,600 

4,500 

2,400 

1,300 

3,800 

1,000 

900 

100 

200 

0 

0 

200 

0 

100 0 

17,100 

4,200 0 

4,200 

1,600 

100 

23,000 

500 

23,500 

12,500 

3,100 

1,300 

400 

200 

200 

100 

100 

300 

0 

0 

0 

0 

0 

0 

18,200 

1,000 0 

1,000 

11,400 

1,100 

31,700 

600 

32,300 

4 

14,500 

8,300 

300 

100 

0 

100 

0 

100 

200 

700 

100 

0 

0 

0 

0 

24,400 

400 

0 

400 

800 

100 

25,700 

300 

26,000 

0.2 ± 0.2 

o.o 

0.3 ± 0.1 

0.2 ± 0.2 

o.o 

o.o 

o.o 

0.1 ± 0.1 

0.3 ± 0.3 

o.o 

o.o 

o.o 

0.1 ± 0.5 

o.o 

2.3 ± 1.0 

3.5 ± 1.0 

0.1 ± 0.1 

0.1 ± 0.1 

0.2 ± 0.1 

o.o 

0.0 

3.7±1.3 

0.2 ± 0.2 

3.9 ± 1.3 

Cover 

2.9 ± 0.5 

11.0 ± 1.1 

4.9 ± 0.8 

3.5 ± 0.5 

2.0 ± 0.2 

2.0 ± 0.6 

0.8 ± 0.5 

0.0 

o.o 

0.0 

o.o 

1.1 ± 0.5 

o.o 

0.1 ± 0.1 

0.0 

28.3 ± 1.8 

0.2 ± 0.1 

0.0 

0.2 ± 0.1 

0.1 ± 0.1 

0.0 

28.6 ± 1.5 

4.6 ± 0.8 

33.2 ± 1.2 

3 

17.6 ± 1.0 

7.8 ± 1.0 

3.1 ± 0.7 

0.8 ± 0.2 

0.6 ± 0.2 

o.o 

o.o 

0.1 ± 0.1 

0.1 ± 0.1 

0.0 

0.0 

o.o 

0.0 

o.o 

o.o 

30.1 ± 1. 6 

0.1 ± 0.1 

o.o 

0.1 ± 0.1 

0.9 ± 0.2 

o.o 

31.1 ± 1.4 

2.9 ± 0.4 

34.0 ± 1.3 

4 

20.6 ± 1.0 

5.5 ± 0.8 

0.4 ± 0.2 

o.o 

o.o 

0.3 ± 0.2 

o.o 

o.o 

o.o 

1.0 ± 0.4 

o.o 

o.o 

o.o 

o.o 

o.o 

27.8 ± 1.4 

o.o 

o.o 

0.0 

0.2 ± 0.1 

0.0 

28.0 ± 1.4 

2.4 ± 0.2 

30.4 ± 1.4 

1Grasses include Stipa speciosa, Oryzopsis hymenoides Oryzopsis webberi, Hilaria jamesii, and Sitanian hystrix. Heavy grazing 

by burros precluded differentiation to species. 

2Includes Machaeranthera tortifolia, Echinocereus engelmanii, Eurotia lanata, Tetradymia axillaris and Stanleya elata. 

Tables 77 
Table 8. Density and cover of perennial vegetation on three debris flows originating in the Kingston Peak(?) Formation in 

western Wood Canyon 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the ~ean] 

Species 

Shrubs: 

Coleogyne ramosissima 

Lycium andersonii 

Ephedra nevadensis 

Grayia spinosa 

Acamptopappus shockley; 

Tetradymia axillaris 

Haplopappus cooperi 

Artemisia spinescens 

Artemisia tridentata 

Dalea fremontii 

Chrysothamnus viscidiflorus 

Eurotia Lanata 

Hymenoclea salsola 

Thamnosma montana 

Subtotal 

Herbaceous perennials: 

Machaeranthera tortifolia 

Sphaeralcea rusbyi 

Castilleja chromosa 

Subtotal 

Grasses1 

Total live 

Dead 

Total 

A 

4,700 

2,600 

1,500 

1,900 

700 

200 

1,500 

2,100 

0 

0 

100 

100 

100 

100 

15,600 

2,300 

700 

400 

3,400 

19,900 

Density 

B 

1,300 

2,000 

600 

5,100 

8,500 

300 

100 

300 

0 

0 

0 

800 

0 

0 

19,000 

1,900 

2,200 

0 

4,100 

5,000 

38,900 28,100 

1,400 600 

c 

7,900 

1,400 

2,000 

1,000 

100 

400 

100 

1,900 

100 

100 

0 

0 

200 

0 

15,200 

1,300 

300 

100 

1,700 

9,000 

25,900 

1,000 

40,300 28,700 26,900 

A 

8.2 ± 1.4 

7.3 ± 1.8 

5.7 ± 0.9 

3.2 ± 0.8 

0.8 ± 0.6 

0.7 ± 0.5 

1.0 ± 0.4 

0.5 ± 0.2 

0.0 

0.3 ± 0.2 

o.o 

o.o 

0.0 

0.0 

27.7 ± 2.7 

0.6 ± 0.2 

0.0 

o.o 

0.6 ± 0.2 

2.6 ± 0.3 

30.9 ± 2.7 

6.9 ± 0.7 

Cover 

B 

2.2 ± 0.6 

6.1 ± 1.2 

1.1 ± 0.3 

7.6 ± 1.3 

7.8 ± 0.9 

0.6 ± 0.3 

0.1 ± 0.1 

0.2 ± 0.1 

o.o 

0.0 

0.1 ± 0.1 

0.3 ± 0.2 

0.0 

0.0 

26.1 ± 2.1 

0.2 ± 0.1 

0.1 ± 0.1 

o.o 

0.3 ± 0.1 

1.7 ± 0.2 

28.1 ± 2.1 

9.1 ± 0.9 

37.8 ± 2.8 37.2 ± 2.3 

c 

13.6 ± 2.9 

2.3 ± 0.8 

6.6 ± 1.8 

1.6 ± 0.4 

0.2 ± 0.2 

2.0 ± 0.5 

0.0 

0.4 ± 0.2 

0.0 

0.0 

o.o 

o.o 

0.3 ± 0.2 

o.o 

27.0 ± 3.6 

0.4 ± 0.2 

0.0 

o.o 

0.4 ± 0.2 

1.6 ± 0.3 

29.0 ± 3.6 

6.5 ± 0.6 

35.6 ± 3.6 

1 Grasses include Stipa speciosa, Oryzopsis hymenoides, Oryzopsis webberi, Hilaria jamesii, and 

Sitanian hystrix. Heavy grazing by burros precluded differentiation to species. 

78 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 9. Carbonate morphologies of soils on debris flows in Wood Canyon 

[See table 6 for soil descriptions. Weight percent carbonate measured by Chittick method (M.N. Machette, 

written commun., 1983). Value in parentheses is detrital dolomite] 

Flow 

2 

3 

4 

A 

B 

c 

Wash 

Horizon 

Maximum 

carbonate stage Description of carbonate Carbonate 

(in weight percent) 

c none 

stage 

No apparent redeposition of pebbles 

with carbonate coatings. 

Coatings on bottoms and some coatings on sides of pebbles. Possibly 

underlain by Stage II carbonate horizon 

(50 em bel ow?). 

c2ca stage Coatings on bottoms and sides of pebbles. 

Weak coatings on tops of some pebbles. 

I IBtca 

IICca 

cca 

IIC2ca 

B22ca 

I IC3ca 

vccab 

stage I 

stage III 

stage II 

stage 

stage II 

stage II 

stage IV 

Coatings on sides and bottoms of pebbles. 

Continuous pebble coatings and filling of 

soil matrix with carbonate. 

Full pebble coatings with some carbonate 

disseminated in the soil matrix. 

Coatings on bottoms and sides of pebbles 

with some carbonate disseminated in the 

soil matrix. 

Full pebble coatings with some carbonate 

disseminated in the soil matrix. 

Full pebble coatings. 

Plugged carbonate horizon with overlying 

1 ami nar zone. 

Table 10. Description of soil near the intersection of 4th and Skidoo 

Streets (fig. 9, site B), Skidoo townsite 

[Source material: alluvium consisting of fragmental dolomite, 

porphyritic granite, and minor schist and vein quartz. See 

table 6 for abbreviations used] 

Depth (em) Horizon Texture Dry color Carbonate 

0-9 A sl 1 10 YR 6/3 

9-17 c gs 12 10 YR 6/3 

17-33 II 1

c gs 10 YR 6/3 

33-60 I I I C~ gsl 10 YR 6/3 

60-100+ IV c4 sl 10 YR 6/3 

Hydrometer analysis of textures: 

18 percent gravel; 73 percent sand- 23 percent silt4 percent clay. 228 percent gravel; 72 percent sand- 24 percent silt4 percent clay. 

stage 

stage 

stage 

Table 11. Physical properties of soils in disturbed and undisturbed 

areas of Skidoo townsite 

2.6 (1.1) 

0.8 (0.6) 

2.3 (1.1) 

o. 7 (0.6) 

8.4 (1.0) 

0.5 (1.1) 

8.4 (1.9) 

l. 2 (0. 7) 

[All values are ±1 standard error of the mean. The moisture content at 

the time of measurement was between 1.5 and 4.0 percent by volume. 

u, undisturbed] 

Site Number of Bulk de~sity Penetration depth 

years since (g/cm ) (em) 

abandonment 

Active Road 0 1.81 ± 0.03 4.4 ± 0.1 

1st Street 63 1.63 ± 0.02 8.1 ± 0.1 

2nd Street 63 1.62 ± 0.01 8.7 ± 0.2 t~ontgomery Street 74 1. 50 ± 0.02 9.3 ± 0.2 

Montgomery Control u 1. 53 ± 0.03 9.9 ± 0.2 

Abandoned East Road 64? 1.65 ± 0.02 6.7 ± 0.2 

East Road Control u 1. 55 ± 0.02 9.4 ± 0.2 

Tables 79 
~ 

0 

;:;c 

~ "'0 

0 

::I 

'll 

1'1) 

a 

$ Table 12. Density and cover of perennial vegetation at Skidoo townsite C1Q 

~ 

a s· [Density in number per hectare; cover in percent. All values are ±1 standard error of the mean] 

::I 

0 

0 

!a" 

c 

as:~) 

::I 

n 

... 1'1) 

0 

1'1) 

a 

::r 

< 

~ 

~ 

z 

a 

s· 

::I 

~ 

~ 0 

::I 

c 

3 

1'1) 

~ ("') 

~ 

~ 

3 

~-

Species 

Shrubs: 

Grayi a spi nos a Artemisia spinescens 

Ephedra nevadensis L~cium andersonii 

Ch r~sothamnus v1 scidi fl orus Artemisia tridentata H~menoc1ea sa1sola 

Atriplex canescens 

Chr~sothamnus nauseosus Acamptopappus shockle~i 

Tetrad~mia spinosa 

Eurotia lanata 

Subtotal 

Herbaceous perennials: 

Stan 1 ey a e 1 at a Sphaeralcea ambigua 

Mirabilis froebelii 

Subtotal 

Grasses 1 

Total live 

Dead 

Total 

Mont go me ry Street 

Disturbed Control 

Density Cover Density Cover 

5,900 ± 500 9.8 ± 0.9 7,400 ± 800 14.6 ± 1.2 

28,400 ± 1,400 10.1 ± 1.0 12,400 ± 1,700 4.8 ± 0.5 

1,500 ± 200 4.1 ± 0.9 800 ± 100 3.2 ± 0.8 

1,200 ± 300 1.1 ± 0.3 900 ± 100 0.8 ± 0.2 

700 ± 200 0.5 ± 0.2 200 ± lOU 0.2 ± 0.1 

0 0.0 0 o.o 

0 0.1 ± 0.1 0 0.1 ± 0.1 

0 o.o 0 o.o 

0 0.0 0 o.o 

0 o.o 0 o.o 

0 o.o 100 ± 100 o.o 

100 ± 100 o.o 0 o.o 

37,800 ± 1,600 25.7 ± 1.6 21,800 ± 1,900 23.7 ± 1.5 

100 ± 100 o.o 500 ± 200 0.1 ± o.o 

1,000 ± 300 0.1 ± o.o 400 ± 100 o.o 

0 0.0 0 o.o - 1,100 ± 300 0.1 ± o.o 900 ± 200 0.1 ± o.o 

2,700 ± 600 0.5 ± 0.2 2,400 ± 400 0.6 ± 0.1 

41,600 ± 1,600 26.3 ± 1.6 25,100 ± 2,000 24.4 ± 1.5 

1,800 ± 300 --- 1,700 ± 300 ---

43,400 ± 1,700 --- 26,800 ± 2,100 ---

1st and 2nd Streets 

Disturbed Control 

Density Cover Density 

5,500 ± 1,500 5.5 ± 0.8 5,000 ± 400 

7,700 ± 1,700 2.1 ± 0.4 6,400 ± 700 

700 ± 200 3.3 ± 1.2 2,100 ± 300 

400 ± 0 0.3 ± 0.1 1,100 ± 200 

2,900 ± 500 4.2 ± 0.5 300 ± 200 

0 0.0 100 ± 100 

900 ± 500 0.6 ± 0.2 300 ± 100 

100 ± 100 0.6 ± 0.1 0 

100 ± 100 0.1 ± 0.1 0 

0 o.o 100 ± 100 

0 o.o 0 

100 ± 100 0.2 ± o.o 0 

18,400 ± 2,500 16.9 ± 1.3 15,400 ± 1,000 

-

-

0 o.o 400 ± 100 

3,400 ± 1,300 0.1 ± 0.0 1,200 ± 400 

0 o.o 100 ± 100 

3,400 ± 1,300 0.1 ± o.o 1,700 ± 400 

-

- 9,100 ± 3,600 0.3 ± 0.1 18,700 ± 7,900 

30,800 ± 4,600 17.3 ± 1.3 35,800 ± 7,900 

1,400 ± 300 4.3 ± 0.8 1,100 ± 300 

-

- 32,200 ± 4,600 21.6 ± 1.5 36,900 ± 8,000 

1Grasses include Hilaria jamesii, Stipa speciosa, and Sitanian hystrix. Heavy grazing by burros precluded differentiation to species. 

Cover 

14.0 ± 1.1 

1.6 ± 0.8 

7.2 ± 0.7 

1.2 ± 0.8 

0.6 ± 0.4 

0.2 ± 0.2 

0.1 ± 0.1 

0.0 

0.0 

o.o 

o.o 

o.o 

-

24.9 ± 1.8 

o.o 

o.o 

o.o 

-

o.o 

0.4 ± 0.2 

25.3 ± 1.8 

4.0 ± 0.8 

29.3 ± 2.0 
Table 13. Calculated dry-weight biomass of abundant woody perennials at Skidoo townsite 

[All values are in kilograms per hectare and are ±1 standard error of the mean, as defined in 

the section "Methods"] 

Species Montgomery Montgomery lst and 2nd 

Street control Streets 

Grayia spinosa 3,900 ± 800 5,300 ± 1,100 1,300 ± 400 

Artemisia spinescens 

Ephedra nevadensis 

1,200 ± 200 

600 ± 100 

300 ± 

300 ± 

100 200 ± 100 

100 500 ± 200 

Lycium andersonii 

Chrysothamnus viscidiflorus 

500 ± 100 

200 ± 0 

100 ± 0 1500 ± 500 

0 ± 0 700 ± 200 

1Volume amounts taken from those in Montgomery Street and control. 

Table 14. Cover of cryptogamic crusts in disturbed and 

undisturbed areas and estimated recovery time at Skidoo 

townsite 

[Cover in percent. 2 All va~ues are ±1 standard error of the mean, based on 

40 plots of 0.1U m (4.0 m ) total area. Estimated recovery time, in years, 

assumes 0-percent cover at i nit i a 1 abandonment ] 

Site Cover Estimated recovery 

(percent) time 

1st and 2nd Streets 16,3 ± 2.7 110 

1st and 2nd Streets control 28.1 ± 2.7 

Montgomery Street 22.0 ± 3.1 110 

Montgomery Street control 32.1 ± 3.1 

1st and 2nd 

Streets cont ro 1 

1,700 ± 300 

100 ± 0 

800 ± 300 

1100 ± 100 

100 ± 0 

Table 15. Cover of perennial vegetation along three segments of the Skidoo pipeline corridor at Harrisburg Flats 

[Cover in percent. All values are ±1 standard error of the mean] 

Location ------------------- Length of intercept -------- Harrisburg Flats 

665 m Sand Dune 190 m Rocky Slope 445 m 

Species 

Shrubs: 

Grayia spinosa 

Chrysothamnus viscidiflorus 

Lycium andersonii 

Ephedra nevadensis 

Artemisia spinescens 

Tetradymia spinosa 

Haplopappus cooperi 

Hymenoclea salsola 

ACamptopappus shockleyi 

Atriplex canescens Salazaria mexicana 

Eurotia lanata 

Dalea fremontii 

Subtotal 

Herbaceous perennials: 

Sphaeralcea rusbyi 

Grasses1 

Total live 

Dead 

Total cover 

Pipeline 

4.8 ± 0.8 

12.1 ± 1.1 

0.6 ± 0.2 

2.4 ± 0.6 

1.4 ± 0.3 

0.5 ± 0.2 

o.o 

0.1 ± 0.1 

0.1 ± 0.1 

1.4 ± 0.3 

0.0 

o.o 

0.7 ± 0.3 

24.1 ± 1.6 

0.2 ± 0.1 

0.3 ± 0.1 

24.6 ± 1.6 

5.1 ± 0.5 

29.7 ± 1.7 

Control 

8.8 ± 1.0 

7.6 ± 0.8 

2.2 ± 0.3 

1.8 ± 0.5 

1.2 ± 0.2 

0.2 ± 0.1 

o.o 

0.1 ± 0.1 

o.o 

0.3 ± 0.1 

o.o 

0.3 ± 0.1 

0.0 

22.5 ± 1.4 

0.2 ± 0.1 

0.6 ± 0.1 

23.3 ± 1.2 

6.2 ± 0.5 

29.5 ± 1.4 

Pipeline 

1.7 ± 1.0 

1.3 ± 0.9 

0.0 

8.3 ± 2.2 

0.0 

0.0 

0.0 

10.9 ± 2.3 

o.o 

1.2 ± 0.8 

0.0 

o.o 

o.o 

23.4 ± 3.5 

0.1 ± 0.1 

0.1 ± 0.1 

23.6 ± 3.0 

3.3 ± 0.7 

26.9 ± 3.1 

Control 

0.0 

0.2 ± 0 

0.1 ± 0 

8.0 ± 2.2 

o.o 

0.6 ± 0.6 

0.0 

9.3 ± 2.1 

0.0 

0.3 ± 0.3 

o.o 

o.o 

o.o 

18.5 ± 3.1 

o.o 

0.1 ± 0 

18.6 ± 2.9 

5.6 ± 0.9 

24.2 ± 3.4 

Pipeline 

0.2 ± 0.2 

3.3 ± 0.8 

0.9 ± 0.4 

3.6 ± 0.7 

o.o 

0.2 ± 0.1 

7.6 ± 1.1 

1.9 ± 0.5 

1.1 ± 0.4 

Ll.O 

o.o 

0.0 

0.7 ± 0.3 

19.5 ± 1.7 

0.0 

1.1 ± 0.3 

20.6 ± 1.5 

2.7 ± 0.4 

23.3 ± 1.6 

Control 

1.8 ± 0.5 

6.1 ± 1.1 

4.9 ± 0.9 

7.0 ± 0.9 

0.0 

0.8 ± 0.4 

4.5 ± 0.7 

0.6 ± 0.2 

2.5 ± 0.6 

0.0 

0.6 ± 0.4 

0.0 

0.2 ± 0.1 

29.0 ± 2.1 

o.o 

0.3 ± 0.1 

29.3 ± 1.5 

3.3 ± 0.4 

32.6 ± 1.6 

1Grasses are Stipa speciosa, Oryzopsis hymenoides, and Sitanian hystrix. Heavy grazing by burros precluded 

differentiation to species. 

Tables 81 
Table 16. Density and cover of perennial vegetation along the Skidoo pipeline corridor in Wood 

Canyon 

[Data for the controls are repeated from table 8. Density in number per hectare; cover in 

percent, All values are ±1 standard error of the mean] 

Pipeline Control 

Species Density Cover Density Cover 

Debris flow A, Coleogyne ramosissima assemblage 

Shrubs: 

Coleogyne ramosissima 1,500 i 700 1.3 t 0.4 4,700 t 500 B,2 t 1.4 

Lxcium andersonii 700 i 300 2.i:J t 1.6 2,600 i 400 7.3±1.8 

Grayia spinosa 400 i 300 0.1 t 0.1 1,900 t 100 3.2 ± 0.8 

Ephedra nevadensis 900 i 300 2.6 t 1.5 1,500 i 200 5.7 ± 0.9 

Acamptopappus shocklexi 7,700 ± 2,500 4,5 t 1.5 700 ± 200 0.8 ± 0,6 

Tetradxmia axillaris 200 ± 200 1.1 t 1.1 200 i 100 0.7 t 0.5 

Haplopappus cooperi 3,000 t 2,300 2.2 t 1.0 1,500 ± 500 1.0 ± 0.4 

Artemisia spinescens 500 i 300 o.o 2,100 i 1,200 0.5 t 0.2 

Dalea fremontii 100 t 100 0.2 t 0.2 0 0.3 t 0.2 

Chrxsotharnnus vi sci di fl orus 5,000 t 2,900 4.2 ± 2.4 100 ± 100 o.o 

Eurotia lanata 200 ± 100 0.0 100 ± 100 0.0 

Hxmenoclea salsola 900 t 800 0.5 ± 0.4 100 ± 100 o.o Chr~sothamnus nauseosus 100 t 100 0.1 ± 0.1 0 0.0 

Thamnosma montana 0 o.o 100 ± 100 0.0 

Subtota 1 21,200 ± 4,600 19.7 t 3.9 15,600 ± 1,500 27.7 t 2.7 

Herbacious perennials: 

Machaeranthera tortifolia 7,100 i 3,500 0,6 t 0,3 2,300 i 600 0.6 ± 0.2 

Sphaeralcea rusbxi 2,400 ± 1,400 o.o 700 t 200 o.o 

Castilleja chromosa 200 t 100 o.o 400 ± 200 o.o 

Subtotal 9,700 t 3,800 0.6 t 0.3 3,400 t 700 0.6 t 0.2 

Grasses 1 20,700 ± 6,800 2.2 i 0.7 19,900 t 1,700 2.6 t 0.3 

Total live 51,600 t 9,000 22.5 t 4.0 38,900 t 2,400 30.9 t 2.7 

Dead 1,000 ± 600 3.8 t 1.1 1,400 t 200 6.9 ± 0.7 

Total 52,600 ± 9,100 26.3 t 4.1 40,300 t 2,400 37.8 ± 2.8 

Debris flow B, Acamptopappus-Grayia-Lycium assemblage 

Shrubs: 

Acamptopappus shocklexi 16,300 ± 1,400 16.6 ± 1.8 8,500 ± 400 7.8 ± 0.9 

Grayia spinosa 900 t 400 1.0 t 0.4 5,100 ± 600 7.6 ± 1.3 

Lxcium andersonii 1,200 ± 500 1.9 ± 0.4 2,000 ± 100 6.1 ± 1.2 

Coleo9xne ramosissima 900 ± 300 1.0 ± 0.3 1,300 ± 500 2.2 ± 0.6 

Ephedra nevadensis 700 ± 200 2.9 ± 0.6 600 ± 100 1.1 ± 0.3 

Tetradxmia axillaris 500 ± 200 1.1 ± 0.3 300 ± 100 0.6 ± 0.3 

Eurotia lanata 300 ± 100 0.1 ± o.o 800 ± 400 0.3 ± 0.2 

Chrxsothamnus viscidiflorus 100 ± 100 0.1 ± 0.1 0 0.1 ± 0.1 

~rtemisia spinescens 0 o.o 300 ± 200 0.2 ± 0.1 

Hxmenoclea salsola 200 ± 100 0.3 ± 0.3 0 o.o 

Haplopappus cooperi 100 ± 100 o.o 100 ± 100 0.1 ± 0.1 

Chrxsothamnus nauseosus 100 ± 100 0.1 ± 0.1 0 o.o 

Artemisia tridentata 100 ± 100 0.3 ± 0.3 0 o.o 

Subtotal 21,400 ± 1,600 25.4 ± 2.1 19,000 t 1,000 26.1 ± 2.1 

Herbaceous perennials: 

Machaeranthera tortifolia 3,600 ± 1,300 0.5 ± 0.1 1,900 ± 600 0.2 ± 0.1 

Sphaeralcea rusbxi 2,000 ± 500 0.1 ± 0.1 2,200 ± 500 0.1 ± 0.1 

Castilleja chromosa 100 ± 100 0.0 0 o.o 

Mirabilis froebelii 100 ± 100 o.o 0 o.o 

Subtota 1 5,800 ± 1,400 0.6 ± 0.1 4,100 ± 800 0.3 ± 0.1 

Grasses1 21,500 ± 3,400 3.3 ± 0.4 5,000 ± 700 1.7 ± 0.2 

Total live 48,700 ± 4,000 29.3 ± 2.1 28,100 ± 1,500 28.1 ± 2.1 

Dead 900 t 200 4.3 t 0.6 600 t 200 9.1 ± 0.9 

Total 49,600 t 4,000 33.6 t 2.2 28,700 t 1,500 37.2 t 2.3 

82 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 16. Density and cover of perennial vegetation along the Skidoo pipeline corridor in Wood 

Canyon-Continued 

Pipeline Control 

Species Density Cover Density Cover 

Debris flow C, Coleogyne assemblage 

Shrubs: 

Coleogyne ramosissima 11,700 ± 1,400 12.0 ± 1.6 7,900 ± 500 13.6 ± 2.9 E~hedra nevadensis 700 ± 200 1.0 ± 0.4 2,000 ± 800 6.6 ± 1.8 

Ctcium andersonii 300 ± 100 0.2 ± 0.1 1,400 ± 300 2.3 ± 0.8 

Tetradtmia s~inosa 200 ± 100 0.2 ± 0.2 400 ± 200 2.0 ± 0.5 

Grayi a s~i nos a 100 ± 100 0.3 ± 0.2 1,000 ± 100 1.6 ± 0.4 

Artemisia axillaris 1,000 ± 300 0.1 ± 0.1 1,900 t 100 0.4 ± 0.2 

Rtmenoc1ea sa1sola 1,000 ± 500 0.8 ± 0.5 200 ± 200 0.3 ± 0.2 

Ha~lo~a~~us coo~eri 3,200 ± 1,900 3.2 ± 1.5 100 t 100 o.o Acam~to~a~~us shockleti 1,100 ± 700 1.1 ± 0.7 100 ± 100 0.2 ± 0.2 

Chrtsothamnus nauseosus 600 ± 400 2.0 ± 1.2 0 o.o 

Chrtsothamnus teretifolius 1,100 ± 1,000 0.9 ± 0.4 0 o.o 

Chrtsothamnus viscidiflorus 500 ± 400 0.6 ± 0.4 0 o.o 

Artem1sia tridentata 100 ± 100 0.4 ± 0.3 100 ± 100 o.o 

Dalea fremontii 100 ± 100 0.2 ± 0.2 100 ± 100 o.o 

Subtotal 21,700 ± 2,800 23.0 ± 2.8 15,200 ± 1,100 27.0 ± 3.6 

Herbaceous perennials: 

Machaeranthera tortifolia 4,300 ± 600 0.4 ± 0.2 1,300 ± 900 0.4 ± 0.2 S~haeralcea rusbti 400 ± 200 o.o 300 ± 100 o.o 

Castflleja chromosa 300 ± 200 0.0 100 ± 100 o.o 

Subtotal 5,000 ± 700 0.4 t 0.2 1,700 ± 1,100 0.4 ± 0.2 

Grasses 1 14,900 ± 3,700 1.7 ± 0.4 9,000 ± 1,400 1.6 ± 0.3 

Total 1 ive 41,600 ± 4,700 25.1 ± 3.0 25,900 ± 2,000 29.0 ± 3.6 

Dead 1,900 ± 800 4.4 ± 0.6 1,000 t 5UU 6.5 ± 0.6 

Total 43,500 ± 4,800 2':1.5 ± 2.9 26,900 ± 2,100 35.5 ± 3.6 

1Grasses include Sti~a s~eciosa, Hilaria jamesii, Sitanian hystrix, grazing by burros precluded differentiation to species. 

and Oryzo~si s sp. Heavy 

Table 17. Calculated dry-weight biomass for abundant woody perennials along three segments of the Skidoo pipeline corridor in Wood 

Canyon 

[All values are ±1 standard error of the mean] 

Species 

Coleogyne ramosissima 

Lycium andersonii 

Grayia spinosa 

Ephedra nevadensis 

Acamptopappus shockleyi 

Haplopappus cooperi 

Artemisia spinescens 

Chrysothamnus viscidiflorus 

Flow A 

Pipeline 

400 ± 200 

300 ± 200 

100 ± 100 

400 ± 200 

700 ± 300 

600 ± 500 

100 

1,300 ± 800 

Control 

2,000 ± 500 

1,300 ± 300 

600 ± 100 

200 ± 0 

100 ± 100 

300 ± 100 

100 ± 100 

100 

Flow B 

Pipeline 

200 ± 100 

500 ± 300 

300 ± 100 

300 ± 100 

1,500 ± 300 

100 

u 

100 

Control 

500 ± 200 

1,000 ± 200 

1,600 ± 300 

100 ± 100 

800 ± 200 

100 

100 

0 

Flow C 

Pipe 1 i ne 

3,000 ± 800 

100 ± 100 

100 

300 ± 100 

100 ± 100 

600 ± 400 

100 

100 ± 100 

Control 

3,300 ± 700 

700 ± 200 

300 ± 100 

300 ± 0 

100 

100 

100 ± 100 

0 

Tables 83 
Table 18. Cover of perennial vegetation along the Skidoo pipeline corridor and control areas at Nemo Crest, 

including a nearby road 

[Cover in percent. All values are ±1 standard error of the mean] 

Species 

Shrubs: 

Coleo~ne ramosissima 

Grayia spinosa 

Ephedra nevadensis L~cium andersonii 

Eurotia lanata 

Artemisia tridentata Tetrad~mia spinosa 

Artemisia spinescens 

Atriplex canescens 

Acamptopappus shockle~i 

Eriogonum fasciculatum Chr~sothamnus viscidiflorus Chr~sothamnus nauseosus 

Haplopappus cooperi 

Hymenoclea salsola 

Subtotal 

Herbaceous perennials: 

Sphaeralcea rusb~i 

Brickellia oblongifolia 

Subtota 1 

Grasses 1 

Total 1 i ve 

Dead 

Total 

Downslope 

control 

11.7 ± 1.5 

4.1 ± 1.2 

2.7 ± 1.0 

3.0 ± 0.9 

1.0 ± 0.9 

0.5 ± 0.5 

0.0 

0.1 ± 0.1 

o.o 

0.0 

0.1 ± 0.1 

0.0 

o.o 

o.o 

o.o 

23.2 ± 2.6 

0.0 

o.o 

o.o 

9.6 ± 1.0 

32.8 ± 2.8 

3.0 ± 0.5 

35.8 ± 2.8 

Pipeline Road 

1.6 ± 0.5 0.6 ± 0.3 

1.5 ± 0.5 o.o 

0.9 ± 0.5 0.2 ± 0.2 

1.2 ± 0.8 0.0 

0.8 ± 0.4 0.6 ± 0.2 

0.7 ± 0.4 1.9 ± 0.9 

0.0 o.o 

0.3 ± 0.2 o.o 

o.o o.o 

Ll.2 ± 0.2 0.4 ± 0.2 

0.0 o.o 

1.2 ± 0.6 1.8 ± 1.1 

0.3 ± 0.3 1.1 ± 0.7 

o.o 0.1 ± 0.1 

0.2 ± 0.2 o.o 

8.9 ± 0.8 6.7 ± 1.7 

0.0 0.2 ± 0.1 

0.2 ± 0.2 o.o 

0.2 ± 0.2 0.2 ± 0.1 

10.1 ± 1.0 8.6 ± 1.1 

19.2 ± 1.7 15.5 ± 2.0 

0.3 ± 0.1 0.5 ± 0.2 

19.5 ± 1.7 16.0 ± 2.0 

Upslope 

control 

10.2 ± 1.5 

5.2 ± 1.0 

4.5 ± 1.2 

2.6 ± 0.9 

0.4 ± 0.2 

1.1 ± 0.8 

0.5 ± 0.5 

0.1 ± 0.1 

0.1 ± 0.1 

0.1 ± 0.1 

o.o 

o.o 

0.0 

o.o 

o.o 

24.8 ± 2.5 

0.4 ± 0.4 

0.1 ± 0.1 

0.5 ± 0.5 

7.4 ± 0.8 

32.7 ± 2.7 

3.3 ± 0.6 

36.0 ± 2.8 

1Grasses include Oryzopsis hymenoides, Stipa speciosa, Hilaria jamesii, and Sitanian 

hystrix. Heavy grazing by burros precluded differentiation to species. 

84 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 19. Cover of perennial vegetation along the Skidoo pipeline 

corridor and control area on a sloping segment north of Nemo 

Crest 

[Cover in percent. All values are ±1 standard error of the mean. Transect length was 100 m] 

Species Pipeline Control 

Shrubs: 

Artemisia tridentata 4.3 ± 2.5 17.4 ± 3.6 E~hedra nevadensis 0.2 ± 0.2 4.4 ± 3.6 

Grayia s~inosa o.o 3.1 ± 1.2 

Coleogyne ramosissima o.o 2.8 ± 2.0 

Subtota 1 4.5 ± 2.5 27.7 ± 4.4 

Herbaceous perennial: 

Mi rabi 1 is froebel i i 0.2 ± 0.2 o.o 

Grasses 1 3.6 ± 1.3 2.1 ± 1.4 

Total 1 ive 8.3 ± 2.5 29.8 ± 4.6 

Dead 0.3 ± 0.2 3.1 ± 1.1 

Total 8.6 ± 2.5 32.9 ± 4.7 

1Grasses include Sti~a s~eciosa, Oryzo~sis hymenoides, and 

Hilaria jamesii. Heavy grazing by burros precluded 

differentiation to species. 

Table 20. Cover of perennial vegetation along the Skidoo pipeline corridor and control areas at Wildrose Canyon 

[Cover in percent. All values are ±1 standard error of the mean] 

Location--------------------

Length----------------------

Species 

Trees: 

Pi nus monophyll a 

Juniperus osteosperma 

Shrubs: 

Artemisia tridentata 

Coleog_yne ramosissima 

Ephedra vi ri dis 

Ephedra nevadensi s 

Grayi a spi nos a Chrysothamnus vi sci di fl orus 

Chrysothamnus tereti fol ius 

Tetradym1 a spi nos a 

Dalea fremontii 

E ri ogonum fa sci cul a tum 

Lyc1um andersonii 

Hapl opappus cooperi 

Salvia dorii 

E ri ogonum saxat i 1 e 

Viguieria multiflora 

Lupi nus excubi tus 

E ncel i a vi rgi nensi s 

Subtota 1 

Herbaceous perenni a 1 s: 

Astraga 1 us sp. 

Sphaeralcea rusbyi 

Subtota 1 

Grasses 1 

Total live 

Dead 

Total 

Segment A 

200 m 

Pipeline 

o.o 

o.o 

0.0 

10.4 ± 1.2 

o.o 

2.1 ± 1.3 

o.o 

o.o 

o.o 

5.3 ± 2.2 

0.5 ± 0.3 

0.0 

0.7 ± 0.4 

0.4 ± 0.4 

o.o 

0.0 

o.o 

0.0 

0.4 ± 0.3 

19.8 ± 2.9 

o.o 

0.0 

0.0 

0.0 

19.8 ± 2.9 

Control 

o.o 

0.0 

0.0 

28.7 ± 4.9 

o.o 

12.9 ± 5.0 

2. 2 ± 1.4 

o.o 

o.o 

2.1 ± 1.6 

1.7 ± 1.0 

0.0 

0.7 ± 0.5 

0.5 ± 0.5 

o.o 

0.0 

o.o 

0.0 

0.0 

48.8±7.4 

o.o 

0.2 ± 0.1 

ll. 2 ± ll.1 

0.2 ± 0.2 

49.2 ± 7.4 

Segment B 

200 m 

Pipeline 

o.o 

0.0 

7.8 ± 2.2 

1.3 ± 1.2 

o.o 

0.2 ± 0.1 

0.0 

1.1 ± 0.6 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

o.o 

0.0 

0.1 ± 0.1 

0.0 

0.0 

10.5 ± 2.6 

1.9 ± 0.3 

o.o 

1.9 ± 0.3 

2.3 ± 0.2 

14.7 ± 2.6 

Segment C 

500 m 

Cont ro 1 Pipeline Control 

0.0 o.o 0.1 ± 0.1 

o.o o.o o.o 

17.4 ± 3.8 9. 2 ± 1.3 20.4 ± 1.5 

8.7 ± 2.8 0.0 3.3 ± 0.8 

0.0 0.3 ± 0.2 1.3 ± 0.5 

3.0 ± 1.4 o.o 0.7 ± 0.4 

0.2 ± 0.2 o.o o.o 0.3 ± 0.2 0.3 ± 0.2 1.0 ± 0.3 

0.0 0.3 ± 0.2 o.o o.o o.o 0.0 

0.0 0.0 0.0 

0.0 0.9 ± 0.3 0.8 ± 0.3 

o.o o.o 0.0 

0.0 0.0 o.o 0.0 0.2 ± 0.2 0.7 ± 0.3 

0.0 o.o 0.0 

0.1 ± 0.1 0.0 o.o o.o 0.0 0.0 

o.o o.o o.o 

29.7 ± 4. g 11.2 ± 1.4 28.3 ± 1.6 

2.0 ± 0.7 0.3 ± 0.1 0.3 ± 0.1 

o.o o.o o.o 

2.0±0.7 0.3 ± 0.1 0.3 ± 0.1 

1.1±0.2 0.8 ± 0.1 1.4 ± 0.2 

32.8 ± 5.0 12.3 ± 1.4 30.0 ± 1.6 

1.1 ± 0.2 5.6 ± 0.6 

13.4 ± 1.4 35.6 ± 1.7 

Segment D 

400 m 

Pipeline Control 

2. 3 ± 1.1 2.9 ± 1.6 

o.o 1.0 ± 0.7 

17.7 ± 1.8 11.4 ± 1.5 

1.4 ± 0.5 7.2 ± 1.1 

o.o o. 9 ± o. 5 

0.0 0.0 

0.0 0.0 

0.7 ± 0.3 0.6 ± 0.3 

0.1 ± 0.1 0.1 ± 0.1 

0.0 o.o o.o o.o 1.1 ± 0.4 0.5 ± 0.3 

o.o 0.0 

o.o o.o 1.0 ± 0.4 0.6 ± 0.4 

0.1 ± 0.1 0.1 ± 0.1 

o.o o.o 0.3 ± 0.2 0.2 ± 0.2 

o.o 0.0 

24.7 ± 2.1 25.5 ± 2.7 

o.o 0.1 ± 0.1 

o.o 0.0 

o.o 0.1 ± 0.1 

0.7 ± 0.2 0.8 ± 0.2 

25.4 ± 2.1 26.4 ± 2. 7 

1.0 ± 0.3 4. 7 ± 2.0 

26.4 ± 2.1 31.1 ± 2.R 

1Grasses include Stipa speciosa, Oryzopsis sp., and Hilaria jamesii. Heavy grazing by burros precluded differentiation to species. 

Tables 85 
Table 21. Description of soils for terrace sequences A and B in Gold Valley 

[Refer to cross sections in fig. 19 for locations. See table 

6 for abbreviations] 

Depth (em) Horizon Texture Dry color Carbonate 

TERRACE SEQUENCE A 

TA0 -- active wash 

0-2 A gls 10 YR 6/4 

2-30 cl gls 10 YR 6/4 

30-55 c2 gs 10 YR 6/4 

55+ IIC3camb stage IV 

TA1 

0-6 A gls 10 YR 6/3 

6-26 cl gls 10 YR 6/4 

26-50 c2ca gls 10 YR 6/4 stage 

50-80 c3ca gls 10 YR 6/4 stage 

80+ c4ca gs 10 YR 6/4 stage 

TA2 

0-6 A gsl 10 YR 6/4 

6-33 B2 gsl 10 YR 5/3 

33-60 83ca gsl 10 YR 5/3 stage I 

60-80+ cca gs 10 YR 6/3 stage I-ll 

TA3 

0-7 A cl 10 YR 7/3 

7-25 82t s 1-sc 1 7.5 YR 4/4 

25-42 ~3ltca gsl 7. 5 YR 4/4 stage I 

42-52 gsl 7.5 YR 4/4 stage I 

52-95+ c32tca gsl 7.5 YR 5/4 stage II-III ca 

TERRACE SEQUENCE B 

TBo 

0-7 A gs 10 YR 6/3 

7-18 c1ca gs 10 YR 6/3 

18-70+ c2ca gs ll) YR 6/3 stage 

TB1 

0-5 A gls 10 YR 6/3 

5-12 c1 gsl lU YR 6/3 

12-29 c2ca gls 10 YR 6/3 stage 

29-71 c gs 10 YR 6/3 stage 

71-72 IIC3ca gc 5 YR 4/4 stage 

72-100 IIC4ca gs 10 YR 6/3 stage 5ca 

86 Response of Vegetation to Disturbance, Death Valley National Monument, California 
~ o-

;;-

"' 

CQ 

....... 

Table 22. Density and cover of perennial vegetation on terrace sequence A in Gold Valley 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean] 

Species 

Shrubs: 

Ambrosia dumosa 

Larrea tridentata 

Lycium andersonii 

Grayia spinosa 

Ephedra nevadensis 

Thamnosma montana 

Hymenoclea salsola 

Acamptopappus 

sphaerocephalus 

Dalea fremontii 

Haplopappus linearifolius 

Salazaria mexicana 

Eriogonum fasciculatum 

Coleogyne ramosissima 

Subtotal 

Herbaceous perennials: 

Machaeranthera tortifolia 

Eriogonum inflatum 

Mi rabil is bi gel ovi i 

Dyssodi a cooperi 

Stephanomeria pauciflora 

Subtotal 

Grass: 

Stipa speciosa 

Total live 

Dead 

Total 

Density 

300 ± 100 

0 

100 ± 100 

0 

500 ± 100 

100 ± 100 

7,400 ± 200 

0 

200 ± lOU 

700 ± 300 

0 

u 

0 

9,300 ± 400 

0 

2,800 ± 600 

200 ± 100 

400 ± 200 

400 ± 100 

3,800 ± 600 

500 ± 400 

13,600 ± 1,000 

1,300 ± 400 

14,900 ± 1,400 

TA0 

Cover 

0.1 ± 0.1 

o.o 

0.1 ± 0.1 

0.0 

1.7 ± 0.4 

0.1 ± 0.1 

12.8 ± 1.8 

0.0 

1.5 ± 0.9 

0.3 ± 0.2 

0.0 

o.o 

0.0 

16.6 ± 2.2 

0.1 ± 0.1 

0.3 ± 0.1 

0.0 

0.1 ± 0.1 

o.o 

0.5 ± 0.2 

U.l ± 0.1 

17.2 ± 2.3 

1.4 ± 0.5 

18.6 ± 2.3 

Density 

3,200 ± 400 

700 ± 100 

700 ± 100 

500 ± 200 

400 ± 200 

300 ± 200 

700 ± 100 

0 

u 

0 

0 

0 

lOU 

6,500 ± 600 

100 ± 100 

600 ± 200 

0 

0 

0 

700 ± 200 

100 ± lOU 

7,300 ± 600 

700 ± lOU 

8,000 ± 600 

TAl 

Cover 

2.6 ± 0.4 

9.3 ± 1.6 

2.5 ± 0.7 

2.2 ± 0.7 

3.5 ± 0.7 

1.1 ± 0.4 

0.9 ± 0.4 

o.o 

o.o 

0.0 

o.o 

o.o 

0.2 ± 0.2 

22.3 ± 1.9 

0.1 ± 0.1 

0.1 ± 0.1 

o.o 

o.o 

o.o 

0.2 ± 0.1 

0.1 ± 0.1 

22.6 ± 2.0 

1.7 ± 0.3 

24.3 ± 2.0 

Density 

6,300 ± 700 

400 ± 200 

600 ± 200 

700 ± lOU 

700 ± 200 

100 ± 100 

300 ± 200 

0 

0 

0 

100 ± 100 

300 ± 200 

0 

9,500 ± 800 

100 ± 100 

100 ± 100 

300 ± 100 

0 

0 

500 ± 200 

300 ± 100 

10,300 ± 900 

1,000 ± 100 

11,300 ± 900 

TA2 

Cover 

5.8 ± 0.9 

3.5 ± 0.9 

3.9 ± 1.3 

3.0 ± 0.8 

2.0 ± 0.7 

o.o 

0.7 ± 0.3 

o.o 

o.o 

o.o 

0.1 ± 0.1 

0.1 ± 0.1 

o.o 

19.1 ± 0.6 

o.o 

0.1 ± 0.1 

0.1 ± 0.1 

o.o 

o.o 

0.2 ± 0.1 

0.2 ± 0.2 

19.5 ± 0.8 

2.0 ± 0.2 

21.5 ± 0.8 

Density 

15,000 ± 400 

2,200 ± 100 

700 ± 100 

1,100 ± 300 

200 ± 100 

0 

300 ± 100 

100 ± 100 

0 

0 

0 

0 

0 

19,600 ± 500 

100 ± 100 

3,300 ± 700 

100 ± 100 

0 

0 

3,500 ± 700 

0 

23,100 ± 700 

~.500 ± 400 

25,600 ± 900 

TA3 

Cover 

8.9 ± 0.5 

8.4 ± 1.3 

3.0 ± 1.0 

1.6 ± 0.6 

0.7 ± 0.3 

0.2 ± 0.2 

o.o 

0.0 

o.o 

o.o 

0.1 ± 0.1 

o.o 

0.0 

22.9 ± 1.1 

0.2 ± 0.2 

0.1 ± 0.1 

0.0 

o.o 

0.0 

0.3 ± 0.2 

o.o 

23.2 ± 1.2 

1.1 ± 0.2 

24.3 ± 1.2 
Table 23. Density and cover of perennial vegetation on terrace sequence B in Gold Valley 

[Density in number per hectare; cover in percent. All values are ±1 standard error of 

the mean] 

Species 

Shrubs: 

G ray i a s pi nos a 

Larrea tridentata 

Thamnosma montana 

Ephedra nevadensis 

Lycium andersonii 

Salazaria mexicana 

Acamptopappus shockleyi 

Hymenoclea salsola 

Ambrosia dumosa 

Haplopappus cooperi Tetradymia stenolepsis 

Eriogonum fasciculatum 

Dalea fremontii 

Subtotal 

Herbaceous perennials: 

Castilleja chromosa 

Dyssodia cooperi 

Eriogonum inflatum 

Machaeranthera tortifolia 

Mi rabi 1 is bi gel ovi i 

Sphaeralcea ambigua 

Subtotal 

Grass: 

Stipa speciosa 

Total live 

Dead 

Total 

Density 

800 ± 

0 

500 ± 

2,900 ± 

300 ± 

100 ± 

0 

6,000 ± 

300 ± 

0 

100 ± 

600 ± 

100 ± 

11,700 ± 

100 ± 

300 ± 

2,900 ± 

100 ± 

100 ± 

400 ± 

3,900 ± 

200 

100 

500 

100 

100 

600 

200 

0 

200 

0 

900 

100 

200 

700 

100 

100 

200 

800 

600 ± 300 

16,200 ± 1,200 

2,400 ± 300 

18,600 ± 1,200 

TBo 

Cover 

2.9 ± 0.7 

0.1 ± 0.1 

2.1 ± 0.5 

5.4 ± 1.0 

2.4 ± 0.8 

0.2 ± 0.2 

o.o 

10.4 ± 1.6 

0.5 ± 0.2 

0.1 ± 0.1 

0.6 ± 0.4 

1.8 ± 0.6 

0.3 ± 0.2 

26.8 ± 2.6 

0.0 

o.o 

0.2 ± 0.1 

0.0 

0.1 ± 0.1 

0.2 ± 0.2 

0.5 ± 0.3 

0.2 ± 0.2 

27.5 ± 2.6 

5.1 ± 0.4 

32.6 ± 2.6 

88 Response of Vegetation to Disturbance, Death Valley National Monument, California 

Density 

1,500 ± 

300 ± 

500 ± 

1,200 ± 

500 ± 

700 ± 

1,300 ± 

400 ± 

200 ± 

100 ± 

0 

0 

0 

6,700 ± 

0 

100 ± 

200 ± 

0 

300 ± 

0 

600 ± 

100 

100 

200 

300 

0 

200 

500 

200 

100 

0 

700 

0 

200 

100 

300 

2,100 ± 600 

Cover 

5.6 ± 1.0 

5.3 ± 1.0 

2.5 ± 1.0 

2.4 ± 0.7 

1.8 ± 0.4 

1.5 ± 0.5 

1.3 ± 0.5 

0.2 ± 0.1 

0.2 ± 0.1 

0.1 ± 0.1 

0.1 ± 0.1 

o.o 

0.0 

21.0 ± 2.0 

0.0 

o.o 

o.o 

0.0 

0.1 ± 0.1 

o.o 

0.1 ± 0.1 

1.8 ± 0.4 

9,400 ± 1,000 22.9 ± 2.1 

400 ± 200 2.9 ± 0.6 

9,800 ± 1,100 25.8 ± 2.3 
Table 24. Description of soils for terrace sequence C and the Gold Valley 

townsite 

[For an explanation of abbreviations, see table 6] 

Depth (em) Horizon Texture Moist color Carbonate 

Terrace Tc0 

0-7 A gls 10 YR 4/4 

0-32 cl gs 7.5 YR 5/4 stage I 

32-48 I IC2ca gls 7.5 YR 4/4 stage I 

48-54 IIC3ca gs 10 YR 7/2 stage II-III} 

54-65+ IIC4ca gls 7.5 YR 4/4 stage I -II I 

1. plugged zone preferentially in gravel lenses. 

2. plugged in gravel lenses; pebble coatings where sand is present. 

Terrace Tc 1 

0-8 A gls 7.5 YR 6/4 

8-30 cl gsl 7.5 YR 6/4 

30-43 c2ca gkls 7.5 YR 5/4 stage 

43-100+ c3ca gls 5 YR 5/4 stage 

Terrace TC 2 (Gold Valley townsite) 

0-7 A gs 1 7.5 YR 5/4 

7-22 c1 gsl 7.5 YR 5/4 

22-60 c gsl 7.5 YR 5/4 stage 

60-100+ IIC2ca gksl 7.5 YR 5/4 stage 3ca 

Terrace TC3 

0-2 A gls 10 YR 5/3 

2-14 cl gls 10 YR 5/3 

14-52 c2ca gs 10 YR 5/3 stage I 

52-62 1 1831cab gscl 7.5 YR 5/4 stage I 

62-72 IIB32cab gscl 5 YR 5/6 stage I I 

72 + IICcab stage IV 

Terrace Tc4 

0-3 A sl 10 YR 5/3 

3-9 Bl gel 10 YR 5/3 

9-32 B21t gel 7.5 YR 4/4 

32-45 ~22tca gel 7.5 YR 4/4 stage I 

45-53 31ca gl 7.5 YR 5/4 stage II 

53-57+ ~32ca gel 7.5 YR 5/4 stage II-III 

ca. 100 ca stage IV 

Tables 89 
Table 25. Density and cover of perennial vegetation on terrace sequence C in Gold Valley 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean. Tr: species was encountered 

Species TC0 TC 1 TC2 

Density Cover Density Cover Density Cover 

Shrubs: 

Col eostne ramos iss i ma 1 '600 ± 800 7.0 ± 1.6 2,000 ± 100 6.2 ± 0.6 1,300 ± 300 6.3 ± 1.0 Larrea tridentata 0 0.0 0 o.o 100 ± 100 2.2 ± 0.9 L~c i um andersoni i 400 ± 200 0.7 ± 0.4 1' 300 ± 200 4.6 ± 1.1 1,300 ± 100 5.7 ± 1.1 E~hed ra nevadens is 1 '100 ± 400 2.1 ± o. 9 600 ± 300 2.1 ± 0.6 1,400 ± 300 6.8 ± 1.1 Gratia s~inosa 100 ± 100 0.2 ± 0.2 1 '900 ± 400 7.2 ± 0.6 1,200 ± 300 5.1 ± 1.0 Htmenoclea salsola 7,500 ± 3,200 7.1 ± 1.3 1,400 ± 600 2.8 ± 0.6 200 ± 100 0.2 ± 0.1 I hamnosma montana 200 ± 100 0.0 300 ± 200 0.3 ± 0.3 900 ± 500 1.1 ± 0.5 Tetrad~mi a s~i nos a 0 0.0 200 ± 100 0.8 ± 0.4 Tr 0.1 ± 0.1 

Ha~l o~a~~us coo~eri Tr 0.0 0 o.o 0 o.o Ambrosia dumas a 0 0.0 Tr 0 100 ± 100 0.1 ± 0.1 E ri o2onum fa sci cul a tum 1,200 ± 200 3.4 ± 1.0 200 ± 100 0.3 ± 0.2 0 o.o 

Acam~to~a~eus shockl e~i 0 o.o 0 o.o 100 ± 100 o.o Salazaria mexicana 0 o.o 100 ± 100 0.3 ± 0.3 0 o.o Dalea fremontii 500 ± 200 1.7±0.7 0 Tr 0 o.o Encelia virginensis 1 '100 ± 400 0.2 ± 0.2 0 o.o 0 o.o Gutierrezia microce~hala 100 ± 100 0.1 ± 0.1 0 o.o 0 o.o 

Subtotal 13,800 ± 3, 700 22.5 ± 2.6 8,000 ± 900 24.6 ± 1.7 6,600 ± 800 27.6±2.3 

Herbaceous perennials: 

Machaeranthera tortifol i a 200 ± 100 o·.1 ± o.1 700 ± 100 0.2 ± 0.1 300 ± 200 0.1 ± 0.1 S~haera l cea ambi gua 500 ± 200 0.0 100 ± 100 0.0 0 o.o 

E ri ogonum i nfl atum 2,000 ± 600 0.1 ± 0.1 4,400 ± 2 '100 0.1 ± 0.1 2,800 ± 1,000 0.1 ± 0.1 Arabi s ~ul chra Tr o.o 100 ± 100 o.o 0 0.0 

Ste~hanome ria ~aucifl ora 100 ± 100 0.0 0 o.o 0 o.o 

Dyssodi a coo~eri 0 o.o 0 0.0 200 ± 200 0.0 

Subtota 1 2,800 ± 600 0.2 ± 0.1 5,300 ± 2,100 0.3 ± 0.1 3,300 ± 1,000 0.2 ± 0.1 

Grasses: 

Sti~a s~eciosa 400 ± 200 0.1 ± 0.1 300 ± 100 Tr 300 ± 200 0.2 ± 0.1 

Ortzo~si s hymenoides 100 ± 100 Tr 0 o.o 100 ± 100 0.1 ± 0.1 

Subtota 1 500 ± 200 0.1 ± 0.1 300 ± 100 o.o 400 ± 200 0.3 ± 0.2 

Tot a 1 live 17,100 ± 3,800 22.8 ± 2.6 13,600 ± 2,300 24.9±1.7 10,300 ± 1,300 28.1 ± 2.4 Dead 1,800 ± 400 3.5 ± 0.7 4,900 ± 1,400 6.8 ± 0.8 2,400 ± 600 4.2 ± 0.4 

Total 18,900 ± 3,800 26.3 ± 2.7 18,500 ± 2,700 31.7 ± 1.9 12,700 ± 1,400 32.3 ± 2.4 

Table 26. Physical properties of soils in disturbed and undisturbed areas of Gold Valley townsite 

[All values are ±1 standard deviation. u: undisturbed] 

Site 

Active road 

Western 

townsite 

Control TC2 

Estimated 

recovery 

time (years) 

Active road 

Eastern 

townsite 

Control TC3 

Estimated 

recovery 

time (years) 

Number of 

years since 

abandonment 

0 

73 

0 

73? 

Bulk de~sity 

(g/cm ) 

1.56 ± 0.09 

1.43 ± 0.07 

1.35 ± 0.04 

120 

Penetration 

depth (em) 

Peak shear 

strength (kN/m2) 

4.0 ± 0.6 60.0 ± 2.1 

10.1 ± 1.0 37.9 ± 1.5 

13.5 ± 1.8 31.7 ± 1.1 

120 90 

1.6 ± 0.6 

9.2 ± 2.4 

10.5 ± 2.4 

90 

90 Response of Vegetation to Disturbance, Death Valley National Monument, California 

in the transect] 

TC3 

Density Cover 

3,400 ± 1,000 11.9 ± 1.7 

300 ± 200 6.1 ± 1.9 

800 ± 100 2.9 ± 0.8 

900 ± 100 2.0 ± 0.5 

700 ± 200 1.5 ± 0.4 

500 ± 300 0.9 ± 0.6 

100± 0 0.2 ± 0.2 

100 ± 100 0.2 ± 0.2 

Tr 0.2 ± 0.2 

100 ± 100 0.1 ± 0.1 

0 0.0 

0 o.o 

0 0.0 

0 0.0 

0 0.0 

0 o.o 

6,900 ± 1,100 26.0 ± 2.8 

300 ± 100 0.3 ± 0.2 

100 ± 100 o.o 

0 o.o 

0 o.o 

0 o.o 

0 o.o 

400 ± 100 0.3 ± 0.2 

o.o 

o.o 

o.o 

7,300 ± 1 '100 26.3 ± 2.8 

1,200 ± 200 3.1 ± 0.4 

8,500 ± 1,100 29.4 ± 2.0 

Volume moisture 

content (percent) 

9.0 ± 1.6 

8.4 ± 3.5 

8.1 ± 0.6 

4.6 ± 1.0 
Table 27. Density and cover of perennial vegetation at Gold Valley townsite 

[The data from the lower and upper controls {TC2 and TCa) are repeated from table 25. Density in number per hectare; cover in percent. All values are ±1 

standard error of the mean. 

Species 

Shrubs: 

Coleo~ne ramosissima 

Larrea tridentata 

[~c i um andersoni i 

tEhedra nevadens is 

Gra~i a SEl nos a H:imenocl ea sa 1 so 1 a 

i'hamnosma montana 

Tetrad~mi a SEi nasa 

HaEl OEaEEUS cooEeri RaEi OEaEEUS 1 ari si fol ius l!;mbrosi a dumas a 

trio~onum fasciculatum 

AcamEtOEaEEUS shockl eyi 

Subtotal 

Herbaceous perennials: 

Machaeranthera torti folia 

SEhaera 1 cea ambi sua 

E ri ogonum i nfl a tum 

Dyssodi a cooEeri 

Subtota 1 

Grasses: 

St i Ea sEeci osa 

OryzoEsi s hymenoides 

Subtota 1 

Total 1 ive 

Dead 

Total 

Tr: species was encountere in the transects] 

Lower control Western Eastern 

(TC2) townsite townsite 

Density Cover Density Cover Density Cover 

1 ,3DO ± 300 6.3 ± 1.0 1,000 ± 300 4.0 t 1.0 1' 100 ± 200 3.1 ± 0.6 

100 t 100 2.2 t 0.9 0 o.o 0 o.o 1,300 t 100 5.7 t 1.1 700 t 200 3.8 t 1.4 1,100 ± 100 4.4 t 1.0 1,400 t 300 6.8 t 1.1 1,300 ± 400 6.5 t 1.4 2,400 ± 300 9.5 t 0.9 1,200 t 300 5.1 t 1.0 200 ± 100 1.5 t 0.5 900 ± 200 6.3 ± 1.2 200 t 100 0.2 t 0.1 11,400 t 2,500 5.6 t 0.5 1,500 ± 300 1.7 t 0.6 

900 t 500 1.1 t 0.5 200 t 100 0.7 t 0.3 400 t 200 1.1 t 0.5 

Tr 0.1 ± 0.1 100 t 0 1.4 t 0.8 100 ± 100 2.2 ± 0.6 

0 o.o 900 ± 500 1.1 ± 0.4 900 ± 300 2.5 ± 1.1 

0 o.o 100 ± 100 0.1 ± 0.1 0 o.o 100 ± 100 0.1±0.1 0 0.0 0 o.o 0 0.0 Tr 0.1 ± 0.1 0 o.o 100 ± 100 o.o 400 ± 400 0.3 ± 0.2 600 ± 300 1.0 ± 0.4 

6,600 ± 800 27.6 ± 2.3 16,300 ± 2,600 25.1 ± 2.5 9,000 ± 700 3l.R ± 2.4 

300 ± 200 0.1±0.1 400 ± 100 o.o 400 ± 200 0.1 ± 0.1 

0 o.o 200 ± 200 0.1 ± 0.1 0 o.o 2,800 ± 1,000 0.1 ± 0.1 2,500 ± 500 0.2 ± 0.1 2,800 ± 700 0.1 ± 0.1 

200 ± 200 0.0 0 o.o 100 ± 100 o.o 

3,300 t 1,000 0.2 ± 0.1 3,100 ± 500 0.3 ± 0.1 3,300 ± 800 0.2 ± 0.1 

300 ± 200 0.2 ± 0.1 300 ± 200 Tr 800 ± 200 0.4 t 0.1 

100 ± 100 0.1 ± 0.1 0 o.o 0 o.o 

400 ± 200 0.3 ± 0.1 300 ± 200 Tr 800 ± 200 0.4 t 0.1 

10,300 ± 1,300 28.1 ± 2.4 19,700 ± 2,700 25.4 ± 2.!> 13 , 100 ± 1 , 000 32.4 t 2.4 

2,400 ± 600 4.2 ± 0.4 2,100 ± 800 2.6 ± 0.4 2,400 ± 700 3.5 ± 0.4 

12,700 ± 1,400 32.3 ± 2.4 21,800 t 2,800 28.0 ± 2.6 15,500 ± 1,300 35.9 ± 2.5 

Table 28. Carbonate morphologies for soils on terrace sequences in 

Gold Valley 

[See tables 21 and 24 for soil descriptions] 

Maximum 

carbonate Carbonate 

Terrace Horizon sta9e Descri~tion ~ercenta9e 1 

TAo c2 

TA Weak pebble coatings on 1 c3ca stage 

bottoms and sides 

TA2 cca stage I-II Continuous with some interpebble fillings 

TA3 cca stage I I -I I I Plugged horizon with 

laminar horizons at depth 

TB0 c2ca stage Faint coatings on bottoms 

of pebbles 

TB1 c3ca stage Coatings on bottoms and 

sides of pebbles 

TC0 IIC3ca stage I I-I I I Not pedogenic; probably 10.4 (7 0 3) 

gully-bed cementation 

Tc1 c3ca stage Discontinuous coatings 6ol (8ol) on bottoms of pebbles 

TC 2 c2ca stage Continuous coatings on 6. 2 (7 0 3) 

sides and bottoms of 

pebbles 

TC 3 I IB32cab stage II Continuous pebble coatings 

with interped filling; 

this carbonate horizon is 

associated with overlying 

younger material 

TC4 cca stage IV Laminar horizon over plugged horizon 

1Measured by Chittick method (MoNo Machette, written communo, 1983)o 

Dolomite percentages are in parentheses. 

Upper cant ro 1 

(TC3) 

Density Cover 

3' 400 t 1 '000 11.9 t 1.7 

300 t 200 6.1 t 1.9 

800 t 100 2.9 t 0.8 

900 t 100 2.0 t 0.5 

700 t 200 1.5 t 0.4 

500 t 300 0.9 t 0.6 

100 t 0 0.2 ± 0.2 

100 ± 100 0.2 ± 0.2 

Tr 0.2 ± 0.2 

0 o.o 100 ± 100 0.1 t 0.1 

0 o.o 0 0.0 

6,900 ± 1 '100 26.0 ± 2.R 

300 ± 200 0,3 ± 0.2 

100 ± 100 o.o 0 0.0 

0 o.o 

400 ± 100 0.3 ± 0.2 

0 o.o 0 o.o 

o.o 

7,300 ± 1,100 26.3 ± 2.8 

1,200 ± 200 3.1 ± 0.4 

8, 500 ± 1 , 100 29.4 ± 2.9 

Tables 91 
Table 29. Description of soi Is for Greenwater, Furnace, and 

Kunze townsites and Greenwater controls C and D 

[For abbreviations and nomenclature, see table 6] 

Depth (em) Horizon Texture Dry color 

GREENWATER 

Townsite 

0-7 A gsl 10 YR 6/4 

7-15 B1 gscl 7.5 YR 6/6 

15-35 B2t gscl YR 4/6 

35-75+ cca 

Control c 

0-ll A gls 10 YR 4/3 

11-20 B1 gsl 7.5 YR 6/4 

20-38 B2t gscl 7.5 YR 5/4 

38-65+ cca 

Control D 

0-6 A gls 10 YR 7/3 

6-17 c1 gsl 7.5 YR 7/4 

17-65+ c2ca gs 1 7.5 YR 7/4 

FURNACE 

Townsite 

0-9 A gls 7.5 YR 6/4 

9-25 B1 gsl 7.5 YR 6/4 

25-37 B2tca gs 1 YR 6/4 

37-48 B3ca gs YR 6/4 

48-65+ cca gs 

KUNZE 

Townsite 

0-7 A gs 1 7.5 YR 5/4 

7-35 c1 gsl 7.5 YR 6/5 

35-65+ gs 1 7.5 YR 6/5 

Carbonate 

stage III-IV 

stage I I-II I 

stage 

stage 

stage 

stage I 

stage I 

Table 30. Penetration depths of disturbed and undisturbed soils 

in Greenwater and Furnace townsites 

[All values are ±1 standard error of the mean. All 

pairs marked with an asterisk are significantly 

different at the f < 0.05 level, using at-test] 

Years since Penetration 

Area measured disturbance depth (em) 

Greenwater 

Active road 0 1.5 ± 0.1 

Abandoned road 73 6.7 ± 0.2* 

Control C 9.2 ± 0.3* 

Townsite A 73 7.5 ± 0.2* 

Townsite B 73 9.9 ± 0.2 

Control D 9.4 ± 0.2 

Cleared area E 73 10.7 ± 0.2 

Control F 11.4 ± 0.3 

Furnace 

Active road 0 4.6 ± 0.1* 

Townsite A 73 9.4 ± 0.2* 

Control B 11.2 ± 0.3 

92 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 31. Density and cover of perennial vegetation in disturbed sites A and Band control sites C and D at lower Greenwater townsite 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean. Tr: species was encountered in the transects] 

Species Townsite A Townsite B Control Control 

Density Cover Density Cover Density Cover Density 

Shrubs: 

L~c i urn andersoni i 300 ± 100 1.1 t 0.4 300 ± 100 1.3 t 0.5 1,200 ± 100 6.4 t 0.8 800 t 200 

Eehedra nevadens is 600 t 100 1.8 t 0.4 700 ± 200 3.4 t 0.5 1,300 ± 200 4.6 t 0.6 1,500 t 200 Menodora sei nescens 400 ± 100 1.8 ± 0.4 300 ± 100 0.4 ± 0.2 2,300 ± 300 4.0 ± 0.4 2,500 ± 300 

Larrea t ri dentata 0 0.0 0 o.o 200 ± 100 4.0 ± 1.7 200 ± 100 

Gra~i a sei nos a 400 ± 100 2.1 ± 0.8 200 ± 200 0.7 ± 0.5 1,100 ± 300 2.Q ± 0.9 700 ± 100 

Haeloeaeeus sp. 1 7,200 ± 1,500 7.5±1.4 3,100 ± 200 3.9±0.7 3,100 ± 900 2.9 ± 0.9 3,900 ± 700 

Tetrad~mi a stenoleesis Tr o.o 100 ± 100 0.2 ± 0.2 100 ± 100 0.7 ± 0.3 400 ± 100 

H~menoc 1 ea sa 1 so 1 a 8, 300 ± 600 10.0 ± 0.6 6,100 ± 400 9.5 ± 0.3 400 ± 200 0.5 ± 0.3 400 ± 200 Thamnosma montana 700 ± 300 1.5 ± 0.8 300 ± 200 1. 5 ± 0.6 500 ± 200 0.5 ± 0.3 400 ± 200 

Salazaria mexicana 0 o.o 200 ± 100 0.7 ± 0.4 0 0.0 100 ± 100 Ambrosia dumosa 100 ± 100 0.2 ± 0.1 100 ± 100 o.o Tr o.o 0 

Sub tot a 1 18,000 ± 1,600 26.0 ± 2.0 11,400 ± 600 21.6 ± 1.4 10,200 ± 1,100 26.5 ± 2.3 10,900 ± 800 

Herbaceous perenni a 1 s: 

Se haera 1 cea ambi \IU a 1,300 ± 200 0.2 ± 0.1 100 ± 100 0.1±0.1 800 ± 100 0.1 t 0.1 300 ± 200 

Mirabilis bi9elovii 600 t 200 0.2 ± 0.1 Tr o.o 100 ± 100 0.1 t 0.1 100 ± 100 

Dyssodi a cooperi 1,000 ± 600 0.3 ± 0.1 500 ± 300 0.1 ± 0.1 Tr o.o 900 t 200 

Subtotal 2,900 t 600 0.7 ± 0.2 600 t 300 0.2 ± 0.1 900 t 200 0.2 ± 0.1 1 '300 t 200 

Grass: 

Stipa seeciosa 5. 700 ± 400 3.7 ± 0.6 11,400 t 800 6.1 t 0.3 2,900 ± 700 1.4 ± 0.4 7,100 ± 500 

Total 1 ive 26.600 ± 1, 900 30.4 ± 1.3 23,400 ± 1,300 27.9 ± 0.7 14,000 ± 1,200 28.1 ± 2.1 19,200 ± 1,400 Dead 

Total 

1Haeloeaeeus sp. 

1, 200 ± 400 3.7±1.1 700 ± 200 1.5 ± 0.5 1,000 ± 200 3.5 ± 1.0 1,100 ± 200 

27,800 ± 1, 900 34.1 ± 1. 7 24,100 ± 1,400 29.4 ± 0.9 15,000 ± 1,200 31.6 ± 2.3 20,300 ± 1,500 

includes _!h. cooeeri with minor amounts of H. laricifolius. 

Table 32. Density and cover of perennial vegetation in cleared area E and control site F at upper 

Greenwater townsite 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean. Tr: species was encountered in the transects; nd: no data] 

Species Cleared area E Control F 

Density Cover Density Cover 

Shrubs: 

Menodora seinescens 1,200 ± 500 2.4 ± 0.9 4,000 ± 700 7.4 ± 1.5 L~cium andersonii 300 ± 100 1.5 ± 0.8 1,500 ± 300 7.3 ± 1.3 Gra~ia s2inosa 1 400 ± 200 0.5 ± 0.3 2,000 ± 200 4.6 ± 0.5 

HaElOEaeEus sp. 5,200 ± 1,200 6.8 ± 0.9 5,300 ± 1,300 4.6 ± 0.8 

tEhedra nevadensis 800 ± 100 4.2 ± 0.6 1,300 ± 300 4.3 ± 0.6 

fhamnosma montana 600 ± 400 1.4 i 0.6 700 ± 200 1.5 ± 0.8 Coleo~ne ramosissima 0 o.o 300 i 100 1.1 ± 0.7 H~menoclea salsola 3,500 i 600 7.2 i 0.8 1,800 ± 400 0.6 ± 0.4 Tetrad~mia stenoleesis Tr 0.1 ± 0.1 Tr o.o 

Euroti a 1 a nata 0 0.0 100 ± 100 o.o 

Salazaria mexicana Tr 0.1 ± 0.1 0 o.o 

Subtotal 12,000 ± 1,500 24.2 ± 1.9 17,000 ± 1,600 31.4 ± 2.6 

Herbaceous perennials: 

SEhaeralcea ambi9ua 1,500 ± 300 0.1 ± 0.1 800 ± 300 0.1 i 0.1 

Machaeranthera tortifolia 100 ± 100 Tr 0 Tr 

Subtotal 1,600 i 300 0.1 ± 0.1 800 i 300 0.1 ± 0.1 

Grass: 

StiEa speciosa 14,300 ± 900 6.1 ± 0.9 4,900 ± 900 1.3 ± 0.4 

Total live 27,900 ± 1,000 30.4 i 1.2 22,700 ± 2,000 32.8 ± 1.6 

Dead 1,500 ± 400 nd 1,100 ± 200 nd 

Total 29,400 ± 1,100 23,800 ± 2,000 

1

Hael o2aepus sp. includes .!h_ coo2e ri with minor amounts of .!h_ laricifolius. 

Cover 

3.8 t 1.1 

4.0 t 0.5 

4.6 ± 1.2 

3.7 ± 0.9 

1.8 ± 0.2 

5.1 t 1.3 

1.1 ± 0.7 

0.7 ± 0.2 

0.7 ± 0.3 

0.9 ± 0.6 

o.o 

26.4 ± 2.5 

Tr 

Tr 

0.3 ± 0.2 

0.3 t 0.2 

3.0 ± 0.6 

29.7 ± 1. 7 

2.9 ± 1.0 

32.6 ± 2.0 

Tables 93 
Table 33. Calculated dry-weight biomass for abundant woody perennials and the perennial 

grass Stipa in lower Greenwater townsite 

[Biomass in kilograms per hectare. All values are ±1 standard error of the mean] 

Species 

Menodora spinescens 

Larrea tridentata 

Lycium andersonii 

Haplopappus sp. 

Ephedra nevadensis 

Grayia spinosa 

Hymenoclea salsola 

Thamnosma montana 

Stipa speciosa 

Townsite A 

400 ± 200 

0 

500 ± 200 

3,300 ± 1,100 

200 ± 100 

300 ± 300 

5,300 ± 1,200 

200 ± 100 

100 

Townsite B 

200 ± 100 

0 

500 ± 200 

600 ± 200 

400 ± 100 

200 ± 200 

2,500 ± 600 

100 ± 0 

100 ± 100 

Control C 

1,600 ± 400 

1,100 ± 300 

800 ± 100 

700 ± 300 

400 ± 100 

500 ± 100 

100 ± 100 

100 ± 0 

100 

Control D 

1,000 ± 300 

1,100 ± 600 

1,000 ± 300 

2,100 ± 500 

400 ± 100 

400 ± 100 

100 ± 100 

100 ± 0 

100 

1Haplopappus sp. includes H. cooperi with minor amounts of H. laricifolius. 

Table 34. Calculated dry-weight biomass for abundant woody 

perennials and the perennial grass Stipa in upper Greenwater 

townsite 

Table 35. Density and biomass of perennial vegetation on 16 

house pads of varying size at Greenwater townsite 

[Biomass in kilograms per hectare. All values are ±1 

standard error of the mean] 

Species 

Mendora spinescens 

Lycium andersonli 

Hapl opappus sp. 

Grayi a spi nosa Hymenoclea salsola 

Ephedra nevadensis 

Thamnosma montana 

St i pa speci osa 

Cleared Area E 

1,000 ± 500 

500 ± 200 

1,500 ± 700 

300 ± 200 

2,100 ± 600 

600 ± 200 

100 ± 100 

100 ± 100 

Control F 

6,600 ± 2,100 

2,600 ± 700 

1,900 ± 900 

1,000 ± 200 

900 ± 300 

600 ± 200 

200 ± 100 

100 

1Haplopappus sp. includes~ cooperi with minor amounts of 

H. laricifolius. 

[Area per house pad =50m2 ± 6.5 m2; all values are ±1 

standard error of the mean. Biomass data obtained from 

measurements in other disturbed areas of the townsite ] 

Species Density Biomass 

(number/ha) (kg/ha) 

Shrubs: 

Hymenoclea sals£la 

Haplopappus sp. 

Lycium andersonii 

Ephedra nevadensis 

Grayi a spi nosa Larrea tridentata 

12,600 ± 1,400 8,100 ± 1,900 

Subtotal 

Herbaceous perennials: 

Sphaeralcea ambigua 

E ri ogonum i nfl atum 

Dyssodia cooperi 

Mirabilis bigelovii 

Subtotal 

Grass: 

Stipa speciosa 

Total live 

Dead 

Total 

900 ± 300 400 ± 200 

500 ± 100 800 ± 200 

300 ± 100 100 ± 0 

200 ± 100 200 ± 100 

100 ± 100 600 ± 600 

14,600 ± 1,700 

3,000 ± 300 

900 ± 500 

200 ± 200 

100 ± 100 

4,200 ± 600 

3,700 ± 800 100 

22,500 ± 1,800 

800 ± 200 

23,300 ± 1,900 

1Haplopappus sp. includes~ cooperi and H. laricifolius. 

94 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 36. Density and cover of perennial vegetation at Furnace and Kunze townsites and at Furnace control 

[Density in number per hectare; cover in percent. All values are ±1 standard error of the mean] 

Furnace Furnace Kunze 

Species cont ro 1 townsite townsite 

Density Cover Density Cover Density 

Shrubs: 

Menodora s~inescens 4,600 t 500 8.1 t 0.8 100 t 100 0.1 t 0.1 200 t 200 

Larrea tridentata 300 t 200 4.8 t 1.2 100 ± 100 0.5 t 0.4 0 

Ltcium andersonii 1,100 t 300 4.4 t 1.0 700 t 200 5.9 t 1.3 400 t 100 

Gratia s~inosa 700 ± 300 1.8 t 0.6 300 t 100 0.2 t 0.1 100 t 100 Ha~lo~a~~us sp.1 1,100 t 500 1.1 t 0.4 100 t 100 0.1 t 0.1 0 E~hedra nevadensis 300 t 100 0.9 t 0.3 100 t 0 0.4 t 0.3 100 ± 100 

Salazaria mexicana 200 t 200 0.4 ± 0.3 0 o.o 100 ± 100 

Htmenoclea salsola 100 ± 100 o.o 2,900 ± 400 4.4 ± 0.7 7,600 ± 1,200 

ihamnosma montana 100 ± 100 0.2 ± 0.1 200 ± 100 0.5 ± 0.2 100 ± 100 

Tetradtmia s~inosa 100 ± 100 0.2 ± 0.2 0 o.o Tr 

E ri 09onum fasci cul atum 0 o.o 0 o.o 100 ± 100 Acam~to~a~~us shockleyi 100 ± 100 o.o 0 o.o 100 ± 100 

Subtotal 8,700 ± 800 21.9 t 2.0 4,100 ± 500 12.1 ± 1.6 8,800 ± 1,200 

Herbaceous perennials: 

D~ssodi a coo~eri 200 ± 200 o.o 2,400 t 2,200 0.5 ± 0.4 7,500 ± 3,200 S~haeralcea ambi9ua 200 ± 200 o.o 200 ± 200 0.1 ± 0.1 700 ± 400 

Mirabilis bi9elovii 100 ± 100 o.o 0 o.o 0 

Subtotal 500 ± 300 o.o 2,600 ± 2,200 0.6 ± 0.4 8,200 ± 3,200 

Grasses: 

Sti~a s~eciosa 2,300 ± 400 0.5 ± 0.1 17,700 ± 1,700 8.9 ± 1.2 1,700 ± 700 

Sitani an hyst ri x 0 o.o 0 o.o 800 ± 100 

Subtotal 2,300 ± 400 0.5 t 0.1 17,700 t 1,700 8.9 ± 1.2 2,500 ± 800 

Total 1 ive 11,500 ± 500 22.4 t 1.9 27,400 t 1,400 21.6 ± 1.9 19,500 ± 3,500 

Dead 1,900 t 200 1.6 ± 0.3 700 ± 300 1.9 ± 0.4 

Total 13,400 ± 500 24.0 ± 1.9 25,100 ± 1,600 23.5 ± 1.9 

Ha~lo~a~~us sp. includes~ coo~eri and~ laricifolius. 

Table 37. Calculated dry-weight biomass of abundant woody perennials and the perennial 

grass Stipa at Furnace and Kunze townsites and Furnace control 

[Biomass in kilograms per hectare. All values are ±1 standard error of the 

mean] 

Species Furnace control Furnace townsite Kunze townsite 

Menodora s~inescens 9,500 ± 900 100 ± 100 100 ± 100 

Lxcium andersonii 1,500 ± 400 1,300 ± 300 900 ± 300 

Larrea tridentata 1,200 ± 700 400 ± 400 0 

Graxia s~inosa 1 400 ± 200 200 ± 100 400 ± 100 

Ha~lo~a~~us sp. 400 ± 200 100 ± 0 0 E~hedra nevadensis 200 ± 100 100 ± 100 100 ± 0 

Hxmenoclea salsola 100 ± 0 2,300 ± 500 3,600 ± 800 

Thamnosma montana 100 ± 0 100 ± 0 0 

St i ~a s~eci osa 100 ± 100 100 ± 100 100 

1

Haplopappus sp. includes .!h. cooperi and H. laricifolius. 

Cover 

0.3 t 0.3 

o.o 

3.5 t 1.3 

0.5 t 0.3 

o.o 

0.5 ± 0.3 

O.fi ± 0.4 

14.5 ± 1.4 

0.1 ± 0.1 

o.o 

0.6 ± 0.5 

o.o 

20.6 ± 0.7 

2.0 ± 0.7 

o.o 

o.o 

2.0 ± 0.7 

0.8 ± 0.3 

0.1 ± 0.1 

0.9 t 0.3 

23.5 ± 2.2 

Tables 95 
1..0 

0'\ 

;o 

~ Table 38. Concentration of plant macrofossils found in packrat middens collected near Greenwater townsite ""C 

c 

:J [Values given in logarithm of number of identifiable fragments per kilogram of midden matrix; --,species not present] tl) 

~ 

c 

-

< Midden No.------------------- G4a G7 G8 Gl5 G11a G6b G9d G11b G11c G9b G4b2 G4bl G6c Principal components ~ 

OQ USGS Dating Lab No.---------- -- -- -- -- 1531 1400 1403 1530 1534 1402 1398 1397 1401 scores ~ 

~ Plant species X-axis Y-axis 

cs· 

:J 

.... Coleo~ne ramosissima 1.10 3.52 0.90 1.03 2.00 1.13 -- -- -- -- -- -- -- -0.59 0.75 c Tetradxmia s~inosa 1.58 -- .90 -- 1. 70 -- -.96 .46 0 -- -- -- -- -- -- -- ~ E rodi urn sp. 1.51 -- -- 1.34 -- 1.13 c Salazaria mexicana -- 1.40 -- -- -- 1.13 

a- Machaeranthera tortifolia .80 -- 1.20 -- -- -- -- 1. 51 -- -- -- -- -- -1.00 .09 ~ 

:J Atri~lex confertifolia -- -- -- -- 1. 70 -- -- 2.29 -- -- -- -- -- -.96 .86 I") 

.. ~ Eriogonum fasciculatum .80 -- -- -- 2.18 -- 2.74 2.90 .99 -- -- -- -- -.55 1.38 

0 Graxia s~inosa 1.58 2.55 2.54 -- 2.00 1.13 2.08 1.51 -- 1.04 -- -- -- -.22 .89 ~ Hxmenoclea salsola 1.10 2.91 .90 2.40 2.18 1.43 -- 3.26 3.38 3.08 -- -- -- .30 .97 :r Salvia dorii 1.10 -- -- -- -- -- 1.08 -- 1. 76 2.26 -- -- -- -.83 -.41 

< 

~ Brickellia watsonii 3.41 -- -- -- -- -- 2.38 -- -- 1. 72 -- -- -- -0 77 .05 

-f Larrea tridentata 2.83 1.08 4.36 3.96 2.65 3.44 4.78 3.23 2.90 4.57 3.54 3.46 3.63 2.23 -1.63 

Eurotia lanata 3.34 3.51 3.70 3.03 3.02 2.91 2.68 3.30 2.40 1. 72 1. 76 2.94 3.33 1.65 .25 z 

~ Haeloeaeeus 1aricifolius 3.39 4.36 1.38 3.39 3.52 3.20 4.58 4.17 3.73 4.24 2.38 3.35 3.03 2.17 .44 

5" Lxcium andersonii 2.92 3.24 2.20 1.88 2.78 2.33 3.08 2.60 2.90 2.65 1.54 3.25 2.48 1.32 .17 :J 

~ Eehedra sp. 3.26 2.24 -- 2.03 3.08 2.03 2.76 3.54 3.53 -- 2.46 2.60 2.68 1.12 1.37 

~ Sehaeralcea ambigua 1.88 -- 1.20 2.64 2.54 2.47 2.08 2.60 2.70 1.81 3.00 3.35 2.00 1.01 -.65 

Thamnosma montana 2.98 1.69 -- 1.03 1. 70 1.43 2.08 2.30 1.29 -- 1.36 -- 2.11 .14 1.36 :J 

c Amsinckia cf. tessellata 1.40 1.08 2.08 1.63 2.30 2.13 2.11 -- .99 1. 79 2.11 1.89 1.11 

~ 

3 Thxsanocar~us sp. 1.10 -- -- 1.03 -- 1.13 1.56 2.00 -- 1.51 3.20 2.91 1.11 

~ 

:J Dithxrea californica -- -- 1.38 -- -- -- 1.98 -- .99 1.04 -- 1.08 

~ Ambrosia dumosa .80 -- 1.38 1.03 -- -- 1.86 -- -- 1.51 -- 2.23 -- -.65 -1.57 ~ Atrielex canescens 3.01 -- -- -- -- 1.13 -- -- -- -- -- 1.89 -- -.83 -.07 ~ Castilleja sp. -- -- -- -- -- -- -- -- -- -- -- 3.57 "'I tncelia virginensis 1.03 1.43 2.59 1.71 -.70 -.68 :J -- -- -- -- -- -- -- -- -- ii" cf. Gilia sp. .80 -- 1.20 1.63 -- -- 1.38 2.66 1.59 

Haeloeae~us cooeeri -- 2.35 -- 3.31 -- -- -- -- -- 2.10 -- 1.88 -- -.59 -1.78 

Echinocactus eolxceehalus 1.94 -- -- -- 2.00 -- -- 1.51 -- -- 1.54 1.08 -- -.65 .69 

Leeidium cf. fremontii -- 1. 79 -- 1.34 2.30 -- 2.72 -- 1.89 1. 79 1. 61 3. 72 -- .02 -1.16 O~untia basilaris -- -- 1.20 1.94 -- -- -- -- -- -- 1.91 1.89 2.04 -.53 -1.90 

cf. Steehanomeria exi9ua -- -- -- -- 2.30 -- -- -- .99 

cf. Menodora seinescens -- 1.40 

Graminsae (cf. Stiea seeciosa) -- -- 2.10 1.30 

Bromus rubens -- 1.40 

Number of ~pecies------------- 22 15 16 19 17 16 18 15 15 15 12 16 11 

Midden age ------------------- M M M M M 270 290 400 740 1340 2105 2125 2235 

±70 ±50 ±45 ±120 ±40 ±45 ±50 ±35 

Midden elevation (m)---------- 1350 1360 1340 1380 1410 1350 1350 1410 1410 1350 1350 1350 1350 

Aspect------------------------ NE. E. E. SE. E. NE. NE. E. E. E. NE. NE. NE. 

1 Units are 14c yr B.P. ±standard deviation; M =modern (less than 250 yr). 
Table 39. Plant assemblages occurring on surfaces differentiated by carbonate morphology in 

Death Valley National Monument 

[See tables 7, 8, 22, 23, and 25 for quantitative data on the plant assemblages, and tables 

6, 21, and 24 for descriptions of soils] 

>-

(.!) 

0 

.....J 

0 

:::r:: 

0... 

IX 

0 

:::E: 

l.LJ 

tc:( 

z: 

0 

co 

IX 

c:( 

u 

Wood Canyon Gold Valley 

Granite Metasedimentary Lower terraces Upper terraces 

Mixed Hymenoclea Htmenoclea-

(local Larrea) 

~ Coleogyne) ~· ,__, ~ 

Eehedra-Ltcium- Acametoeaeeus- Larrea-Eehedra Gratia-Coleo~ne- QJ 

g s:: 

Gratia Gratia-Ltcium Ltci urn QJ 

(1j u ...., 0 (/') 0 Coleogtne-Eehedra Eehedra- :::r:: 

Co 1 eo~ne-Ltc i urn 

~ 

~· ,__, ~ 

,__, Coleo~ne-Ltcium- Ambrosia- QJ ...., s:: 

g Eehedra Ltci um-Larrea Vl QJ QJ u (1j ...., 0 ...., (lj.j.J 

(/') .- Vl 

QJ 

Col eo~ne-Larrea a= 

~ 

~· ,__, ~ 

,__, QJ ,__, Col eo~ne Ambrosia-Larrea s:: QJ Q) 

~ ...., u (1j 0 (1j .- ...., ...., Vl 

(/') 

Q) 

a= 

Q) 

~s:: 

~ Q) 

0 u ~ 0 

...., 

;::; "0 Vl 

s:: ·.--

Co 1 eo~ne-La rrea (1j QJ 

g ~o... 

(1j ~· ...., ~~ 

(/') QJ ~· 

!0-a; 

"0...., 

·.-- (1j 

E.-

Table 40. Summary of estimated recovery times for compacted soils at four townsites 

[Values based on a linear model of recovery and a comparison of soil 

properties in active roads, abandoned sites, and undisturbed sites] 

Townsite 

Greenwater (site A) 

Greenwater (abandoned road) 

Furnace 

Skidoo 

Gold Valley (western townsite) 

Gold Valley (eastern townsite) 

Recovery time (in years) based on: 

Penetration 

depth 

100 

110 

100 

80 

120 

90 

Bulk 

density 

90 

120 

Peak 

shear strength 

90 

l.LJ 

C.."l 

c:t: 

Tables 97 
Table 41. Dominant species occurring on surfaces differentiated by degree of disturbance for all 

townsites 

[Dominant species defined as those species contributing 3 percent or more cover, in order of 

decreasing contribution of cover. See tables 12, 27, 31, 32, and 36] 

Townsite Compacted sites Noncompacted sites Control sites 

Skidoo Grayia-ChrysothamnusEphedra 

Artemisia-GrayiaEphedra 

Grayi a-EphedraArtemisia 

Gold Valley Ephedra-HymenocleaColeogyne-Lycium 

Ephedra-Grayi a- Lycium-Coleogyne 

Co 1 eogyne-E phedraLyciumiGrayiaLarrea 

Greenwater: 

Sites A, B, C, D Hymenoclea-HaplopappusSti pa Hymenoclea-StipaHaplopappusLyci um-EphedraMenodora-Larrea2 

Sites E, F Hy~a-Haplopappus- ~ Menodora-LyciumGrayia-HaplopappusEphedra 

Furnace and Kunze Hymenoclea-StipaLycium 

St i pa-Ephedra 

Menodora-LarreaLycium 

1 Larrea contributed less than 3.0 percent cover on terrace TC 2• 2--

Haplopappus and Stipa contributed 5.1 and 3.0 percent cover, respectively, in 

control site D but less than 3.0 percent in control site C. 

Table 42. Dominant species occurring on surfaces differentiated by degree of 

disturbance along segments of the Skidoo pipeline corridor 

[Dominant species defined as those species contributing 3 percent or more cover, in order of decreasing contribution of cover. See tables 15, 16, 18, and 

20] 

Area 

Harrisburg Flats: 

Sand Dune 

Rocky Slope 

Wood Canyon: 

Flows A and C 

Flow B 

Nemo Crest 

Pipeline segments 

Chrysothamnus-Grayia 

Hymenocl ea-Ephedra 

Haplopappus-Ephedra- Chrysothamnus 

Coleogyne1-AcamptopappusChrysothamnus-Haplopappus 

Acamptopappus-grasses 

Grasses 

Control sites 

Grayia-Chrysothamnus 

Hymenocl ea-Ephedra 

Ephedra-Chrysothamnuslyclum-Haplopappus 

Coleogyne-Lycium-EphedraGrayi a 

Acamptopappus-GrayiaLycl um Coleogyne-Grayia-Ephedra 

Wi 1 drose Canyon: 

Segment A Coleogyne-Tetradymia Coleogyne2-Ephedra 

Segments B, C, D Artemisia Artemisia3-Coleogyne 

1coleogyne had 1.3 and 12.0 percent cover on the pipeline segments through 

flows A and C, respectively. 2The difference in cover contributed by Coleogyne between the pipeline segment 

and control site was 18.3 percent. 3The differences in cover contributed by Artemisia between the pipeline 

segments and control sites were 9.6, 11.2, and -6.3 percent, respectively, 

for segments B, C, and D. 

98 Response of Vegetation to Disturbance, Death Valley National Monument, California 
Table 43. Hybrid correlation matrix based on cover and density in townsites containing Larrea tridentata 

Correlations based on density --lower left; correlations based on cover -- upper right 

1site 1* 3* 4* 5 6* 7* 8 9 10* 11 12* 13* 14 15 16* 17* 18 

1* 0.34 0.49 0.70 0.29 0.32 0.62 0.41 0.45 0.58 0.22 0.21 0.70 0.07 0.35 0.42 0.42 0.07 

2 .90 .07 .02 .84 .oo .02 .55 .42 .oo .23 -.06 .09 .39 .51 .14 .43 .33 

3* .59 .54 .28 .04 .14 .29 .20 .28 .37 .13 -.08 .16 -.11 .22 .30 .40 -.08 

4* .97 .84 .58 .02 .53 .77 -.03 .15 .66 -.05 .45 .84 -.11 -.13 .14 -.06 -.10 

5 .88 .95 .71 .85 -.09 -.05 .40 .36 -.06 -.01 -.11 .03 .38 .38 .06 .14 .59 

6* .44 .29 .22 .55 .31 .91 .21 .41 .92 .31 .72 .45 .04 -.04 .46 .22 -.10 

7* .88 .74 .49 .94 .74 .79 .18 .34 .92 .18 .76 .67 -.07 .03 .54 .25 -.09 

8 .53 .57 .31 .49 .54 .56 .59 .88 .35 .85 .04 .32 .77 .60 .41 .58 .21 

9 .82 .75 .49 .79 .75 .59 .81 .88 .59 • 79 .oo .33 • 72 .34 .26 .42 .10 

10* .91 .79 .52 .93 .79 .71 .95 .73 .92 .40 .55 .58 .10 .04 .48 .31 -.10 

11 .53 .53 .28 .53 .51 .68 .66 .98 .88 .76 .05 .25 • 72 .51 .38 .57 .09 

12* .12 .01 -.03 .25 .oo .51 .40 -.06 .08 .19 .06 .47 -.03 -.01 .56 .09 -.02 

13* .97 .86 .53 .98 .85 .50 .91 .50 .81 .92 .53 .28 .12 .12 .27 .09 .oo 

14 .35 .35 .12 .33 .31 .18 .33 .74 .64 .43 .74 -.05 .35 .22 .01 .09 .16 

15 .01 .20 .01 -.06 .13 -.17 -.09 .01 -.06 -.09 -.04 -.11 -.05 -.09 .71 .84 .68 

16* .02 -.07 -.03 .18 -.07 .65 .40 -.04 -.06 .15 .11 .63 .08 -.12 .12 .78 .43 

17* .13 .22 .17 .11 .21 .25 .20 .17 .12 .13 .16 .08 .08 -.08 .80 .47 .29 

18 -.09 .16 .02 -.11 .11 .03 -.08 -.01 -.15 -.15 -.04 .00 -.13 -.12 .26 .26 .46 

19* .28 .14 .09 .44 .15 .76 .63 .13 .17 .42 .27 .68 .35 .oo -.06 .92 .28 .12 

Site No. 1 * 2 3* 4* 6* t* 8 10* 11 12* 13* 14 15 --16* 17* 18 

idisturbed sites 

1 Site No. Site name Site No. Site name Site No. Site name 

(1-5) Wahmonfe townsite (Webb and Wilshire, 1980}: (6-14, 19} Greenwater district: (15-18} Gold Valley townsite: 

1. Streets and avenues 6. Townsite A 15. Lower control (TC 2) 

2. Southwest control 7. Townsite B 16. Western townsite 

3. Old main road 8. Control C 17. Eastern townsite 

4. Townsite 9. Control 0 18. Upper control (TC3) 

5. Northeast control 10. Cleared area E 

11. Contro 1 F 

19. House pads 

12. Kunze townsite 

13. Furnace townsite 

14. Furnace cont ro 1 

Table 44. Amount of variance explained by the first three axes of 

the principal-components solution for sites in Larrea-dominated 

assemblages 

[Values in percent. See table 43 for location of site 

numbers] 

Cumulative variance 

Cover 

Site 

Densitx 

No. X y z X y z 

All 36 59 70 49 65 77 

1 55 57 59 84 87 88 

2 18 51 51 71 77 88 

3 16 16 20 33 36 42 

4 27 69 69 87 87 87 

5 9 40 40 72 78 88 

6 45 74 75 47 77 84 

7 56 96 97 91 96 97 

8 55 83 94 56 61 62 

9 56 67 91 85 92 92 

10 64 88 90 95 95 96 

11 42 57 75 61 62 64 

12 22 52 54 6 55 64 

13 42 58 59 85 86 86 

14 15 43 84 25 37 42 

15 31 68 92 0 2 73 

16 50 50 78 4 94 94 

17 42 57 73 5 24 83 

18 5 31 57 0 8 43 

19 20 89 92 

Tables 99 
...... 

0 

0 

~ 

rl 

-g 

:::s 

Ill 

('!) 

a 

< 

o& 

a s· 

:::s 

0 

0 

!a" 

c 

g-""' 

:::s 

n 

.!0 

0 

('!) 

a 

:r 

~ 

.f 

z 

~ s· 

:::s 

~ 

~ 

g 

c 

3 

('!) 

~ 

n 

~ 

~ 

3 

Qj" 

Table 45. Correlation-coefficient matrix based on cover for sites in the Panamint Range 

1site 

No. 1 2 

1 1.00 0.88 

2 1.00 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

3 

o. 74 

.79 

1.00 

1site No. 

4 5 

o. 76 o. 31 

.94 .35 

.83 .80 

1.00 .38 

1.00 

Site name 

6 7 8 

0.58 0.16 0.09 

• 73 .16 .05 

.92 .35 .24 

• 73 .32 .23 

.86 .15 .04 

1.00 .14 .01 

1.00 .98 

1.00 

-----rr=4J Skidoo townsite: 

1. Montgomery Street 

2. Montgomery Street cont ro 1 

3. 1st-2nd Streets 

4. 1st-2nd Streets control 

9 

-0.01 

-.02 

.24 

.10 

.30 

.19 

.33 

.33 

1.00 

(5-10) Skidoo pipeline on Harrisburg Flats: 

5. Harrisburg Flats pipeline 

6. Harrisburg Flats control 

7. Sand dune pipeline 

8. Sand dune control 

9. Rocky slope pipeline 

10. Rocky slope control 

(11-1:6) Wood Canyon segment of Skidoo pipeline: 

11. Flow A pipeline 

12. Flow A control 

13. Flow B pipeline 

14. Flow B control 

15. Flow C pipeline 

16. Flow C control 

10 11 12 

.18 -0.05 0.24 

.17 -.07 .26 

.54 .27 .24 

.36 .05 .38 

.58 .46 .05 

.51 .33 .23 

.36 .14 .17 

.35 .14 .18 

• 74 .57 .15 

1.00 .78 .45 

1.00 .41 

1.00 

13 14 15 16 17 18 19 20 21 22 

-0.02 0.38 -0.10 0.10 0.13 0.07 -0.08 0.24 -0.07 0.06 

.oo .55 -.08 .10 .21 .11 -.06 .34 -.06 .06 

-.02 .36 -.09 .13 .13 .11 .01 .26 -.07 .10 

.04 .54 -.06 .21 .23 .11 -.07 .40 -.02 .17 

-.05 .13 -.07 .oo .oo .08 .10 .06 -.09 -.01 

-.03 .46 -.09 .04 .15 .15 .06 .24 -.09 .oo .01 -.02 -.03 .18 .oo -.02 -.08 .10 -.00 .17 

.03 -.07 -.01 .21 .00 -.03 -.08 .09 .05 .20 

.09 .oo .15 .05 -.02 .06 .07 .02 -.03 .06 

.25 .34 .02 .20 .04 .04 -.01 .14 .02 .15 

.65 .50 .20 .24 .24 .29 .28 .24 .14 .17 

.15 .53 .62 .84 .74 .28 .07 .81 .64 • 76 

1.00 .68 .06 .07 .10 .15 .14 .11 .01 .03 

1.00 .12 .22 .34 .1 q .03 .40 .09 .13 

1.00 .85 .73 .18 .12 • 71 .83 .87 

1.00 • 78 .20 .05 .83 .89 .98 

1.00 .71 .56 .97 .62 .72 

1.00 .95 .64 .05 .09 

1.00 .47 -.05 -.03 

1.00 .64 .77 

1.00 .89 

1.00 

Site No. Site name ---nT-20) Nemo Crest segment of Skidoo pipeline: 

17. Downs 1 ope cont ro 1 

18. Pipeline segment 

19. Abandoned road 

20. Upslope control 

(21-28) \~ilr:lrose Canyon segment of Skidoo pipeline: 

21. Segment A pipeline 

22. Segment A control 

23. Segment B pipeline 

24. Segment B control 

25. Segment C pipeline 

26. Segment C cant ro 1 

27. Segment 0 pipe 1 i ne 

28. Segment 0 control 

23 24 25 26 27 28 

-0.11 -0.07 -0.10 -0.10 -0.10 -0.14 

-.09 -.06 -.08 -.08 -.09 -.12 

-.06 -.07 -.10 -.09 -.11 -.16 

-.08 -.01 -.07 -.06 -.08 -.11 

.01 -.08 -.07 -.05 -.07 -.10 

-.03 -.09 -.08 -.08 -.09 -.13 

-.09 -.02 -.09 -.08 -.10 -.13 

-.09 .oo -.08 -.07 -.09 -.12 

-.07 -.08 -.10 -.10 -.11 -.16 

-.09 -.07 -.13 -.11 -.13 -.19 

-.01 -.04 -.12 -.09 -.13 -.10 

-.00 -.24 -.12 .oo -.08 .20 

-.03 -.03 -.06 -.05 -.07 -.08 

-.09 -.04 -.11 -.09 -.11 -.07 

.10 .38 -.06 .09 .01 .44 

.05 .38 -.10 .06 -.03 .37 

.lCJ .32 -.02 .09 .oo .34 

.27 .09 .07 .07 .02 .07 

.42 .18 -.23 .21 .18 .17 

.20 .36 .01 .12 .03 .35 

.03 .34 -.09 .06 -.02 .38 

.05 .40 -.09 .OR -.01 .40 

1.00 .90 .94 .95 .92 .83 

1.00 .87 .94 .89 .95 

1.00 .98 .9·8 .81 

1.00 .98 .89 

1.00 .87 

1.00 
Table 46. Cumulative variance explained by the first three axes 

of the principal-components solution for sites in the Panamint 

Range 

[Values in percent. See table 45 for locations of site 

numbers] 

Site X y z 

Total 26 48 63 

1 11 34 54 

2 16 42 67 

3 20 57 91 

4 24 52 75 

5 7 28 52 

6 16 48 82 

7 4 14 15 

8 3 9 10 

9 4 13 13 

10 15 40 45 

11 18 28 28 

12 71 73 80 

13 4 6 6 

14 23 37 39 

15 49 54 82 

16 72 72 92 

17 72 73 82 

18 21 22 22 

19 10 15 16 

20 85 85 89 

21 43 47 76 

22 63 64 85 

23 8 68 94 

24 23 84 94 

25 2 61 97 

26 6 70 97 

27 3 65 96 

28 19 87 91 

Tables 101 
Table 47. Perennial vegetation found at all sites 

[See text for 1 ocat ions, e 1 evat ions, and quantitative data. A 11 Latin names from Munz (1974) and Benson and 

Darrow (1981). Common names from various sources including Jaeger (1941), Munz (1974), Beatley (1976), Kay and 

others (1977), and Benson and Darrow (1981); Abbreviations: x, found on the site described in the text; h, 

found on surrounding hill slopes; h 1 , found on surrounding 1 imestone hill slopes; xn, not on the site, but nearby on similar surface; -, not present] 

Species 

Nutt. var. linfolia 

(D.C.~Rob 

Castilleja chromosa A. Nels 

Chrysothamnus nauseosus var. mohavensi s 

(Greene) Hall and Clem 

Chrysothamnus tereti fol ius (Our. & Hi 1 g.) Hall 

Ch rysothamnus vi sci difl or us (Hook:) Nutt 

Coleog_yne ramosissima Torr 

Cowania mexicana DiDon var. stansburiana (Torr) Jeps 

Dalea fremontii Torr var. minutifolia 

(Parish) L. Benson 

Dyssodi a cooperi Gray 

Echinocactus polycephalus Engelm. S. Bigel 

Echinocereus engelmanii (Parry) Lem 

Encelia virginensis A. Nels. ssp. actoni 

Ephedra funerea Cov. & Mort 

Ephedra nevadensi s Wats 

Ephedra viridis Cov. var. viridis 

Eriogonum fasciculatum Be~ 

Eriogonum heermani. Our. & Hilg 

Eriogonum inflatum Torr & Frem 

Eriogonum saxatile Wats 

Euroti a lanata 

Grayi a spi nos a (Hook) Moq 

Gutierrezia microce hala (DC.) Gray 

Hapl opappus cooperi Gray) Hall 

Haplopappus laricifolius Gray 

Halo a us linearifolius DC 

Hilaria jamesii Torr. Benth 

Hymenoclea salsola T & G var. salsola 

Juniperus osteosperma (Torr.) Little 

Krameria parvifolia Benth 

Larrea tridentata (Sesse & Moe. ex DC.) Cov 

Lepidium fremontii Wats 

Leptodactyl on pungens (Torr.) Rydb. ssp. hall i 

(Pari sti)"Ma'"son 

Lupinus excubitus Jones var. excubitus 

Lyci um andersoni i Gray 

Machaeranthera tortifolia (Gray) Crong. & Keck 

Menodora spi nescens Gray 

Mirabilis bigelovii var. retrorsa (Heller) Munz 

Mirabilis froebelii (Behr) Greene var. froebelii 

Opuntia acanthocarpa Engelm. and Bigel 

Opuntia basilaris Engelm. and Bigel 

Opuntia bigelovii Engelm. var bigelovii 

Or zo sis h menoides (R & S) Ricker 

Oryzopsis webberi Thurb.) Benth. ex Vasey 

Penstemon fl ori dus Bdg. ssp. aust i ni i 

(Eastw) Keck 

Penstemon frutici formi s Cov. ssp. fruticiformi s Petalonyx nitidus Wats 

Pi nus monophyll a Torr & Frem 

Sa 1 azari a me xi can a Torr 

Salvia dorii (Kell.) Abram 

Senecio douglasii DC. var. monoensis 

(Greene) Jeps 

Sitanian hystrix (Nutt) J.G. Sm 

Sphaeralcea ambigua Gray 

Sphaeralcea rusbyi Gray ssp. eremicola 

Stanleya elata Jones 

Stanleya pinnata (Pursh) Britton ssp. pinnata 

Stephanomeria pauciflora (Torr.) Nutt 

Stipa speciosa Trin. and Rupr 

Tetradymia axillaris A. Nels. 

Tetradymia spinosa var. longispina Jones 

Tetradymi a stenolepsi s Greene 

Thamnosma montana Torr. & Frem 

Viguiera multiflora (Nutt) Blake var. nevadensis 

(A. Nels.) Blake 

Yucca brevifolia Engelm 

Common name 

Shockley Goldenhead 

Goldenhead 

Burrobush 

Prince's rock-cress 

Desert sandwort 

Bud sage 

Great Basin sage 

Dapple-pod 

Four-wing saltbush 

Shadscal e 

Spear-leaved brickellia 

Pi non bri eke ll i a 

Desert paintbrush 

Rubber rabbi tbrush 

Roundl eaf rabbi tbrush 

Green rabbi tbrush 

Bl ackbrush 

Cliff rose 

Indigo bush 

Cooper dyssodi a 

Barrel cactus 

E nge 1 man's hedgehog cactus 

Brittlebush 

Death Valley ephedra 

Mormon tea 

Green ephedra 

California buckwheat 

Heerman buckwheat 

Desert trumpet 

Rock buckwheat 

Wi nterfl at 

Spiny hopsage 

Matchweed 

Goldenbush 

Turpentine bush 

Linear-leaf goldenbush 

Ga1leta grass 

Cheesebu sh 

Utah juniper 

Range rat any 

Creosote bush 

Desert alyssum 

Prickly gi1ia 

Adonis 1 upi ne 

Anderson's thornbush 

Mojave aster Spiny menodora 

Desert four o'clock 

Giant four o'clock 

Buckhorn choll a 

Beavertai 1 cactus 

Silver cholla 

Indian ri cegrass 

Ri cegrass 

Inyo beard-tongue 

Death Valley penstemon 

Sandpaper p 1 ant One-leaf pinon pine 

Paperbag bush 

Purple sage 

Groundse 1 

Squi rreltai 1 grass 

Globe ma 11 ow 

Panamint globe ma 11 ow 

Apache p 1 ume 

Prince's plume 

Wire lettuce 

Need1egrass 

Cotton thorn 

Yellow thorn 

Cotton thorn 

Turpentine bush 

Nevada go 1 den eye 

Joshua tree 

1 02 Response of Vegetation to Disturbance, Death Valley National Monument, California 

Wood Can~on debris flows 

1 2 4 A B C 

x x xn xn x x 

x xn xn xn xn xn xn xn xn 

x xn 

X 

xn 

xn 

xn xn 

X X 

xn 

xn 

X 

xn xn 

xn x x 

X X X X 

x xn xn 

X 

xn 

xn xn xn 

X 

X X X 

xn x 

xn xn 

xn xn xn 

xn x 

X 

x xn 

X 

xn xn xn 

X X X 

X 

xn xn 
Gold Valley sites 

Lower Middle Upper Ghost 

(A) (B) (C) town 

X 

X 

X 

X 

xn 

xn 

xn 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

-h 

Ghost towns 

Wahmonie Greenwater Furnace Kunze Skidoo 

xn 

X 

h 

xn 

X 

X X 

h 

xn 

xn 

xn 

X 

X 

X 

h 

X 

X 

h 

X 

h 

X 

X 

h 

h 

xn 

X 

h 

X 

X 

hl 

X 

X 

hl 

X 

h 

hl 

hl 

X 

h 

h 

X 

X 

hl 

X 

hl 

hl 

X 

hl 

Skidoo Pipeline corridor 

Harris- Nemo Wildrose 

burg Crest Canyon 

xn xn 

xn X xn 

X 

xn 

X 

X 

h 

xn 

X 

xn xn 

xn 

xn 

xn 

xn xn 

xn 

xn 

xn xn 

xn 

xn 

xn 

xn 

X 

xn xn 

xn 

X 

Tables 103 


GPO 585-045/78045