U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5095

Vegetation, Substrate, and Eolian Sediment Transport at 

Teesto Wash, Navajo Nation, 2009–2012 
FRONT COVER:

Aerial photograph taken in April 2012 of Teesto Wash, Navajo Nation, approximately 45 miles north of Winslow, Arizona. View is to the southeast. Photo by 

Jon Mason, USGS.
Vegetation, Substrate, and Eolian Sediment 

Transport at Teesto Wash, Navajo Nation, 

2009–2012

By Amy E. Draut, Margaret Hiza Redsteer, and Lee Amoroso

Scientific Investigations Report 2012–5095

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Draut, A.E., Redsteer, M.H., and Amoroso, L., 2012, Vegetation, substrate, and eolian sediment transport at Teesto 

Wash, Navajo Nation, 2009–2012: U.S. Geological Survey Scientific Investigations Report 2012-5095, 71 p.

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reproduce any copyrighted material contained within this report.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Methods...........................................................................................................................................................4

Wind, Precipitation, and Sediment-Transport Measurements .....................................................4

Vegetation and Substrate Measurements........................................................................................6

Results ............................................................................................................................................................7

Discussion.....................................................................................................................................................15

Implications for the Rocky Mountains Snowpack ........................................................................16

Conclusions...................................................................................................................................................18

Acknowledgments.......................................................................................................................................19

References Cited..........................................................................................................................................19

Appendix 1. Supplementary Information .................................................................................................23

Figures

 1. Map of the Southwestern United States, showing the location of the study area ...................2

 2. Trends in precipitation and temperature on the Navajo Nation...................................................3

 3. Photographs of wind-dominated landscapes on the southern Navajo reservation 

near the study area in October 2008..........................................................................................4

 4. Photographs of the weather station, sand traps, and vicinity of study site 7 ............................5

 5. Scale diagram of “pod” configuration used to measure vegetation and substrate.................6

 6. Eolian sediment mobility and transport, wind speed, and rainfall measured 

at study site 7 in 2009 and 2010...................................................................................................8

 7. Eolian sediment mobility and transport, wind speed, and rainfall measured 

at study site 7 in 2011 and 2012...................................................................................................9

 8. Localities in and near the study area..............................................................................................10

 9. Variations in vegetation abundance and species assemblage..................................................10

10. Vegetation cover by study site, showing abundance in March and August 

surveys in 2010–2012..................................................................................................................11

11. Study area in the Navajo Nation......................................................................................................12

12. Substrate composition within circular plots of each pod in March 2010–March 2012..........14

13. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite image, 

showing eolian dust plumes that originated in northeastern Arizona, 

within the Navajo Nation, on the afternoon of May 29, 2011...............................................17

14. Particle-size data for 24 selected samples collected in Big Spring Number Eight 

(BSNE) sediment traps within the study area........................................................................18
Tables

1. Plant varieties identified in the study area near Teesto Wash, Navajo Nation, Arizona. ........13

2. Summary of major site characteristics measured in the study area near Teesto Wash, 

Navajo Nation, Arizona..............................................................................................................15

3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona. ..........................................................................24

4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona ...........................................................................40

5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona ...........................................................................41

6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona ...........................................................................51

7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona ...........................................................................61
Vegetation, Substrate, and Eolian Sediment Transport at 

Teesto Wash, Navajo Nation, 2009–2012

By Amy E. Draut,1 Margaret Hiza Redsteer,2 and Lee Amoroso2

1

U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA 95060. 

2

 U.S. Geological Survey, Flagstaff Science Center, Flagstaff, AZ 86001.

Abstract

On the Navajo Nation, southwestern United States, 

warming temperatures and recent drought have increased 

eolian (windblown) sediment mobility such that large, migrating sand dunes affect grazing lands, housing, and road access. 

We present an assessment of seasonal variations in sand 

transport, mobility, and ground cover (vegetation and substrate) within a 0.2-km2

 study area near Teesto Wash, southern 

Navajo Nation, as part of a multiyear study measuring the 

effects of drought on landscape stability. Sand mobility in the 

study area decreased substantially as one year (2010) with 

near-normal monsoon rainfall somewhat abated a decade-long 

drought, temporarily doubling vegetation cover. The invasive 

annual plant Russian thistle (Salsola sp.), in particular, thrived 

after the monsoon rains of 2010. Vegetation that grew during that year with adequate rain died off rapidly during drier 

conditions in 2011 and 2012, and the proportion of bare, open 

sand area increased steadily after summer 2010. We infer that 

isolated seasonal increases in rainfall will not improve landscape stability in the long term because sustained increase in 

perennial plants, which are more effective than annual plants 

at stabilizing sand against wind erosion, requires multiple 

consecutive seasons of adequate rain. On the basis of climate 

projections, a warmer, drier climate and potentially enhanced 

sediment supply from ephemeral washes may further increase 

eolian sediment transport and dune activity, worsening the 

present challenges to people living in this region. Connections between climate, vegetation cover, and eolian sediment 

erodibility in this region also are highly relevant for studies in other regions worldwide with similar environmental 

characteristics.

Introduction 

The Navajo Nation, comprising the largest tribal reservation within the United States (fig. 1), is presently restricted to 

arid and semiarid lands within the Navajo ancestral homeland. 

These lands have been stressed by drought, land-use practices, 

and rapid population growth during the 20th century. As in 

many other Native American communities, the Navajo people 

face economic disadvantages and, owing to livestock-management regulations and cultural ties, cannot readily relocate 

either their grazing lands or settlements (Redsteer and others, 

2010a). Among the environmental challenges to the Navajo 

Nation are shifting vegetation patterns, including the spread of 

invasive species, and eolian (windblown) sediment mobility. 

Warming temperatures andrecent drought (fig. 2) have 

contributed to reduced streamflow and vegetation loss. These 

factors have increased eolian sediment mobility such that 

regional duststorms are common and large, migrating sand dunes 

now affect grazing lands, housing, and transportation (Redsteer 

and others, 2011). This report presents recent sediment-transport 

and vegetation measurements in order to elucidate and quantify some of the factors affecting landscape stability and sand 

mobility on the Navajo Nation, as part of a study of the effects 

of drought in this region. In addition to affecting the quality of 

life for regional residents, eolian sediment mobility in this part 

of the Colorado Plateau also has important implications for 

the longevity of the Rocky Mountains snowpack and thus for 

regional water supply in the western United States.

With an area of 67,000 km2

 spanning parts of Arizona, 

New Mexico, and Utah (fig. 1), Navajo reservation lands range 

in elevation from 1,200 to 3,000 m, with a regional average 

annual rainfall ranging from 100 to 300 mm. As of 2010, more 

than 169,000 of the 332,000 Navajo tribal members were living on the reservation (Norris and others, 2010). The population grew substantially in the late 20th century; in 2000, the 

median age of the Navajo reservation population was 24 years, 

in comparison with 35.3 years for the general U.S. population 

(U.S. Census Bureau, 2000). The Navajo lifestyle and economy historically have been tied closely to livestock production and husbandry, but for more than a century it has been 

recognized that livestock populations can overgraze Navajo 

lands to a degree that reduces native vegetation substantially 

(Bailey and Bailey, 1986). Around the turn of the 20th century, 

regional vegetation communities began to be affected not only 
2 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

by overgrazing but also by the Eurasian annual plant Russian thistle (Salsola spp.), which spreads quickly on loose, 

sandy soils such as those that occur over much of the Navajo 

Nation. In its dry form known as tumbleweed, Russian thistle 

disperses great distances aided by wind and is one of the most 

widespread invasive plants on Navajo lands today. 

Precipitation occurs bimodally in the southwestern 

United States, during winter storms (December–March) and 

the North American monsoon season (July–September), with 

45 percent of annual precipitation on Navajo lands falling 

during the summer monsoon (Redsteer and others, 2010a). 

These two wet seasons are separated by a dry, windy spring 

(for example, Hack, 1941; Draut and Rubin, 2006; Jewell and 

Nicoll, 2011; Munson and others, 2011). For most of the past 

century precipitation has been declining in Navajo lands (fig. 

2) and climate has been warming more rapidly in the southwestern United States than in many other regions of North 

America, resulting in associated ecologic changes (Westerling 

and others, 2006; Seager, 2007a; Weiss and others, 2009). 

Declining precipitation, a shift from snowfall to rainfall, 

and increased potential evapotranspiration have contributed 

to a reduction in surface water on Navajo lands. At least 30 

streams and lakes that were perennial in the 1920s are now dry 

or ephemeral (Redsteer and others, 2010a). Climate models 

project increasingly drier and warmer conditions throughout 

the southwestern United States for the coming decades (Seager 

and others, 2007b; Solomon and others, 2007; Dominguez and 

others, 2010).

Eolian sand covers much of the Navajo lands (Hack, 

1941). Nearly a third of the Navajo reservation has loose, 

sandy soil that the wind winnows and shapes into dunes; the 

Four Corners region of the Colorado Plateau contains the 

largest area of eolian sand dunes within the southwestern 

United States (Muhs and others, 2003; Muhs and Been, 2004; 

Redsteer and others, 2010a). New sand dunes have formed 

and enlarged substantially on Navajo lands since the mid-20th 

century in areas with sandy soils and sparse vegetation (Redsteer and others, 2011). Particularly after a 1950s drought, loss 

of perennial streamflow left riverbeds dry, providing a source 

from which the wind mobilizes sediment (Redsteer and others, 

2010b). Aerial photographs show evidence for eolian sand 

transport downwind of many streambeds in the Navajo Nation, 

commonly forming well developed dune fields (fig. 1B) 

similar to the so-called “source-bordering dunes” that occur 

Las Vegas Colorado R.

Phoenix

40° 

300 KILOMETERS

115° 110° 

35° 

NV

UT

CA

CO

NM

AZ

ID WY

105° 

NAVAJO

HOPI STUDY AREA

DUNE FIELD

PREVAILING WIND

DIRECTION

500 m

50 m

A

C

B

LIVESTOCK

WATERING AREA

Colorado Plateau

Rocky Mountains

Winslow

Ganado

San Juan Range

North Teesto

110.52° 110.50° 

35.50°

35.52°

N

TEESTO WASH

0 100 200

N

Figure 1. A, Southwestern United States, showing the location 

of the study area. The Hopi reservation is surrounded by the 

Navajo Nation. Regional wind direction over much of the Colorado 

Plateau is from the southwest. B, Aerial photograph of the study 

area shows an eolian dune field downwind of Teesto Wash, an 

ephemeral wash. Vegetation surveys were conducted at 11 study 

sites within the study area, C. Sand transport, wind, and rainfall 

have been measured at study site 7 since 2009. Images © Google 

Earth, 2007.
Introduction 3

50

100

150

200

250

Precipitaion, as percent of average

18

19

20

21

22

23

24

1920 1940 1960 1980 2000

1

2

3

4

5

6

7

1920 1940 1960 1980 2000

1920 1940 1960 1980 2000

Average minimum temperature,

in degrees celsius

A

C

B

Average maximum temperature,

in degrees celsius

Figure 2. Trends in precipitation and temperature on the Navajo Nation. A, Rainfall on the southern Navajo reservation, as a 

percentage of the 1915–2010 average, using combined data from Winslow and Ganado, Arizona, the two weather stations nearest 

the study area with long-term records (see fig. 1A for locations). B, Average monthly minimum temperature measured at Winslow, 

Arizona, from 1915 to 2010. C, Average monthly maximum temperature measured at Winslow, Arizona, from 1915 to 2010. Best-fit linear 

regressions are shown.
4 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

immediately downwind of desert streambeds in other dryland 

regions globally (Bullard and McTainsh, 2003). Eolian sediment mobilization and dune activation commonly occur in 

response to climatic change, not only on Navajo lands but also 

in other field settings (Muhs and Holliday, 1995; Lancaster, 

1997; see reviews by Bullard and Livingstone, 2002, Bullard 

and McTainsh, 2003; and Cornelis, 2006). The environmental 

effects of increased eolian sediment mobility and transport 

during dry intervals are substantial and affect many residents 

of the Navajo Nation—airborne dust reduces air quality, causing health risks, and sand dunes that can migrate as fast as tens 

of meters per year frequently impede road access and have 

even destroyed houses (fig. 3; Redsteer and others, 2010a, b). 

Because the Navajo lands are fairly remote, quantitative 

measurements of environmental parameters are scarce. The 

U.S. Geological Survey (USGS) began a pilot drought-monitoring program there in 2005 that deployed new weather stations. Several years later, this study was expanded to measure 

eolian sediment transport and vegetation. We present some 

results of this monitoring study, with the goal of understanding 

the influence of seasonal weather patterns on eolian sediment 

mobility, and vegetation type and abundance. Eolian sediment mobility is a useful indicator of dryland environmental 

conditions—the air-quality and landscape-stability issues it 

represents are vital to evaluating the habitability of the Navajo 

reservation and the longevity of the Rocky Mountains snowpack as the 21st-century climate becomes warmer and drier. 

Methods

Wind, rainfall, eolian sediment transport, and ground 

cover (vegetation and substrate) were measured between 2009 

and 2012 in a study area that, though small in comparison with 

the vast size of the Navajo Nation, is representative of where 

many settlements are situated. Some 15,000 to 20,000 Navajo 

people reside on landscapes with ground cover similar to that 

of the 0.2-km2 study area—sandy soils on and near dune fields 

and an ephemeral wash, in an area with livestock use and 

occasional offroad-vehicle traffic (fig. 1C). 

Wind, Precipitation, and Sediment-Transport 

Measurements

Wind velocity, precipitation, and eolian sediment 

transport were measured beginning in March 2009 at the site 

marked “7” in figure 1C. A weather station and sand traps 

were deployed approximately 10 m apart, each surrounded by 

fenced enclosures to prevent damage by livestock; the instrument deployments are shown in figure 4. The weather station 

included an Onset wind speed and direction sensor (spinningcup anemometer with wind vane) mounted on a tripod at a 

height of 2 m above the bed. This anemometer measured wind 

speed with 0.2-m/s resolution, and wind direction as vector 

components with a resolution of 1.4° and an accuracy range 

of ±5°. An Onset tipping-bucket rain gage measured precipitation with a resolution of 0.2 mm and an accuracy of ±1 

percent. Wind and precipitation measurements were recorded 

on an OnsetTM digital datalogger. Precipitation was recorded 

as 4-minute total rainfall amounts, and wind speed and wind 

direction every 4 minutes as 4-minute averages using a 3-s 

sampling interval. 

A

C

B

Figure 3. Wind-dominated landscapes on the southern Navajo 

reservation near the study area (fig. 1) in October 2008. A, 

Dunes migrating from left to right across a road. B, Haze from 

airborne dust in an area where sandy soils are readily mobilized 

by wind. Fencepost in center of photograph is 1 m high. C, 

Nonnative Russian thistle plants dominating vegetation in an 

eolian dune field.
Methods 5

Windblown sediment was collected in four passivesampling Big Spring Number Eight (BSNE) traps (Fryrear, 

1986) mounted on a vertical pole 10 m upwind of the weather 

station (fig. 4). Each trap was equipped with a vane that 

turned the sampler into the wind. The bases of the 5-cm-tall 

trap orifices were set at heights of 0.1, 0.4, 0.7, and 1.0 m 

above the ground, so placed because most eolian sediment 

transport occurs within 1 m of the bed (Anderson and Hallet, 1986; Sterk and Raats, 1996; Zobeck and others, 2003). 

Wind-tunnel studies (Goossens and others, 2000) indicate a 

BSNE sand-trap efficiency range of 70–130 percent for the 

wind velocities and sediment grain sizes measured at this 

study site. An efficiency less than 100 percent indicates that 

airflow is directed away from the orifice, such that the trap 

undersamples windblown sediment, whereas an efficiency 

greater than 100 percent indicates that air flow is directed into 

the trap, over sampling windblown sediment. A conservative 

efficiency range of 70–130 percent was used to estimate error 

in the sand-transport data reported here because it is the best 

available for this type of bulk sand-transport data. 

Approximately every 4 weeks, sediment was emptied 

from the traps, oven-dried overnight at 65°C in the USGS laboratory in Santa Cruz, California, and then weighed. Organic 

matter was not removed from sediment samples before weighing, because the organic-matter proportion of the sample was 

negligible. Sediment-transport rates were calculated by dividing the total mass of sediment in the traps by the number of 

days over which it accumulated. To avoid introducing uncertainty, measured sediment fluxes were not extrapolated down 

to the bed; thus, although measurements do not account for the 

absolute total mass flux, trends in relative amounts of transport 

over time still are apparent. Sediment-transport rates were 

normalized to show sediment mobility without the effects of 

varying wind speed over different time intervals; to normalize 

the data, each sediment-flux measurement was divided by the 

cumulative flux predicted for that interval by the Dong and 

others (2003) transport equation. This formulation, a modification of that proposed by O’Brien and Rindlaub (1936), was 

chosen because it treats wind strength as a function of velocity 

rather than shear velocity; to extrapolate shear velocity from 

wind velocity measured at only one height would introduce 

additional, unwanted uncertainty.

Particle-size analysis was performed on 24 sediment 

samples that were selected because they represented eolian 

sediment transport during the spring windy seasons of 2009, 

2010, and 2011. Samples were analyzed at the U.S. Geological 

A B

C D

Figure 4. Weather station, sand traps, and vicinity of study site 7 (see fig. 1C for location). A, Weather station, with anemometer and 

wind-direction sensor mounted on instrument tripod 2 m above ground. The rain gage is on the left; fenced enclosure surrounds the 

station. View is southeastward across Teesto Wash. B, Cistern and cattle near study site 8, viewed from study site 7 across Teesto 

Wash. C, Weather station at study site 7. View northeastward. D, Sand-trap deployment at study site 7. Four Big Spring Number Eight 

(BSNE) sand traps were mounted on a vertical pole and surrounded by a fenced enclosure. White measuring tape along ground was 

used to measure gap length during ground-cover surveys. View southwestward.
6 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Survey’s Geology and Environmental Change Science Center 

laboratory in Denver, Colorado. Bulk samples were split with 

a chute splitter and treated with 30 percent aqueous hydrogen 

peroxide to remove organic matter. Sodium hexametaphosphate was added to all samples as a deflocculant, and the 

samples were shaken on a shaker table for 4 hours to ensure 

deflocculation of clay material. Grain size was determined by 

using a Malvern Mastersizer 2000 laser analyzer. Each sample 

was introduced into an aqueous medium and pumped through 

the laser analyzer for particle-size measurements.

Vegetation and Substrate Measurements

Vegetation and substrate cover were measured once at 

each of the 11 study sites (fig. 1C) during each of five surveys, 

in spring and fall 2010, spring and fall 2011, and spring 2012, 

in a layout of circles and linear transects referred to here as 

a “pod” (Draut and Gillette, 2010; Draut, 2011). As shown 

in figure 5, each pod consisted of two orthogonal transects 

marked out with measuring-tape reels (one oriented parallel and another oriented perpendicular to the prevailing wind 

direction) and five 3-m-radius circles outlined in the sand (one 

in the center of the pod and another at the end of each of the 

four transects). 

Along each of the transects within a pod, gap lengths 

were measured where the measuring tape crossed bare, open 

sand without rocks, biologic soil crust, leaf litter, or overhanging plant canopy. Biologic soil crust, a common component of 

desert ecosystems, consists of cyanobacteria living symbiotically with lichen, mosses, fungi, and algae (Belnap and others, 

2001; Belnap and Lange, 2003). This method of measuring 

gap length was modified from that used by Herrick and others 

(2005), with their criteria to define plant-canopy gaps, as a 

means to measure the spacing and abundance of roughness 

elements, vegetation, and patches of biologic crust that could 

reduce eolian sediment mobility (Ash and Wasson, 1983; 

Leys and Eldridge, 1998; Belnap and Lange, 2003; Goossens, 

2004). The proportion of bare, open sand in the dune field then 

was estimated for each of the 11 study sites by adding all the 

measured gap lengths from each transect to compile a cumulative gap-length measurement representing total gap length as a 

percentage of total transect length. Gap lengths between plant 

bases (basal gap length; Herrick and others, 2005) also were 

measured.

Within each of the five circles in a pod, the percentage of 

vegetation cover was measured, as were the types of substrate 

in which the plants were growing. Vegetation was identified to species level wherever possible, using the names and 

20 m

20 m

3 m

Downwind

Upwind

Figure 5. Scale diagram of “pod” configuration used to measure vegetation and substrate. 
Results 7

descriptions provided by Taylor (1992), Williams (2000), and 

Huisinga and others (2006), supplemented with identifications 

made by experts on plant communities of the Navajo Nation 

area (L. Begay and A. Clifford, oral commun., 2009) and 

maintaining consistency with the U.S. Department of Agriculture plant database (http://plants.usda.gov, accessed June 

20, 2012). Where species identification was uncertain, plants 

were identified by their family or genus, or by designation 

as annual or perennial grass, forb, or shrub. Substrates were 

divided into four categories: open sand, biologic soil crust, 

leaf litter, and rock. To estimate the percentage of cover of 

both plants and substrate, a disc of known size was compared 

with the area covered by a plant, rock, patch of soil crust, or 

other object of interest. The disc (20-cm radius) has an area 

(0.13 m2) approximately 0.5 percent of the circle size studied 

(28.3 m2). By holding a disc of known radius above plants or 

patches of biologic crust to estimate their size and percentage 

of cover, researchers avoided disturbing the ground surface 

unnecessarily, as would happen from handling plants or placing measuring devices directly on sensitive, soil-encrusted 

ground. The uncertainty in this method of ground-cover 

measurement is estimated conservatively to be no more than 

5 percent, on the basis of the consistency of measurements 

made during repeated visits, within the same season, to several 

test circles. Annual variations in plant cover were minimized 

by repeating the surveys of each season within a week of the 

dates on which the survey had been conducted in the previous 

year; thus, the three March surveys (2010, 2011, and 2012) 

were conducted between March 12 and 19, and the two August 

surveys on August 8 and 9 (2010 and 2011).

Vegetation that appeared to be dead but that was still 

rooted in the ground was included in the category of vegetation cover, whereas dead vegetation no longer rooted in the 

ground was classified as litter substrate. Vegetation cover was 

considered to be dead if one specimen of a particular plant 

remained brown and did not bloom during the time when other 

plants of its species were green and blooming, or if some part 

of a shrub was seen to be brown while another part of the 

same shrub was green. With those two exceptions of circumstance, vegetation cover was assumed to be living; especially 

during winter, perennial grasses and shrubs are dormant and so 

do not appear green.

Results 

Seasonal patterns in wind, precipitation, and sediment 

transport varied substantially throughout the study interval 

(figs. 6, 7). Because the anemometer and datalogger deployed 

in the study area malfunctioned several times during 2009 and 

2010, two intervals during those years are represented in figure 

6 by using data collected 1.5 km northwest of the study site 

at another weather station with a configuration similar to that 

at the study site (North Teesto, fig. 1B). Wind and rain data 

from North Teesto are plotted for year days 202–314 (July 21 

to Nov. 10) in 2009, and North Teesto wind data for year days 

91–219 (Apr. 1 to Aug. 7) in 2010, in figure 6. 

As is common in this region, wind velocity (accompanied by dry conditions) and corresponding eolian sediment 

transport were greatest during spring. Sediment-transport rates 

in spring 2009 and 2010 were approximately 10 times higher 

than in other seasons, and springtime sand mobility in those 

years was approximately 10 to 100 times greater than in other 

seasons (fig. 6). Sediment transport and mobility in 2011 were 

markedly lower than in the preceding 2 years, particularly 

during spring (fig. 7), observations consistent with a large 

increase in vegetation cover during 2010, as discussed below.

During the study interval, hydrologic conditions in the 

southwestern United States spanned several years in the La 

Niña phase of the El Niño–Southern Oscillation (ENSO) cycle 

(2009, 2011, 2012) and one weak El Niño year (2010). In 

2009, Arizona recorded its fourth-driest year in 117 years, and 

the preceding 3 years also had been abnormally dry (National 

Climatic Data Center, 2012). Several wetter seasons followed 

in 2010, which was Arizona’s 85th-driest year on record with 

above-normal rainfall state wide, although northeastern Arizona received below-average rainfall (fig. 2). Dry conditions 

returned again in 2011, a year that received below-average 

rainfall and was the 23d driest on record in Arizona. Rainfall 

in the study area occurred predominately during the summer 

monsoon and winter storm seasons, although, unusual for 

that time of year, 15 mm of rain also fell on May 21, 2009. 

The largest rain event measured during the study interval was 

an intense monsoon storm on the evening of July 31, 2010, 

that delivered 38 mm of rain, 29 mm of which fell within 20 

minutes. That rain event produced the only known discharge 

in Teesto Wash during the study interval. Using the slopearea method retroactively to gage discharge in Teesto Wash 

within the study area, we estimated the flow from that event 

to have been approximately 10 m3

/s. Runoff caused by the 

July 31, 2010, storm incised more than 1 m into nearby graded 

gravel roads and formed gullies within eolian sand (fig. 8) that 

remained visible for several months.

Vegetation abundance and species assemblage varied 

substantially between 2010 and 2012, both seasonally and 

longer term (figs. 9–11; tables 1–7). Vegetation assemblages at 

the study sites typically contained from 5 to 15 different plant 

species (tables 1, 3–7). Native plants that commonly occur in 

the study area included perennial bunchgrasses, such as Indian 

ricegrass (Oryzopsis hymenoides, also known as genus Achnatherum), sandhill muhly (Muhlenbergia pungens), galleta 

grass (Pleuraphis jamesii), and several species of dropseed 

(Sporobolus spp.). Common native shrubs and forbs included 

rabbitbrush (Ericameria nauseosus), snakeweed (Gutierrezia 

sarothrae), Mojave indigobush (Psorothamnus arborescens), 

globemallow (Sphaeralcea sp.), and stickleaf (Mentzelia 

pumila). Less common native shrubs included saltbush (Atriplex sp.), ephedra (Ephedra sp.), and narrowleaf yucca (Yucca 

angustissima). In the August 2010 vegetation survey (table 

4), which followed abundant monsoon rainfall, the vegetation 

assemblage in the study area also commonly contained the 
8 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

W Sp Su F

2

4

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8

10

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16 W Sp Su F

A

Sediment mobility

10-5

10

10

10

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-4

50 100 150 200 250 300 350

Year day, 2009 Year day, 2010

Daily rainfall, in millimeters

Daily sediment transport,

in grams per centimeter

B

Diurnal wind Speed,

in meters per second

C

5 D

10

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40

50 100 150 200 250 300 350

W Sp Su F

50 100 150 200 250 300 350

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W Sp Su F

W Sp Su F

50 100 150 200 250 300 350

50 100 150 200 250 300 350

50 100 150 200 250 300 350

W Sp Su F

50 100 150 200 250 300 350

W Sp Su F

W Sp Su F

trap width

Figure 6. Eolian sediment mobility and transport, wind speed, and rainfall measured at study site 7 in 2009 and 2010 (see fig. 1C for 

location). A, Sediment mobility, in dimensionless units obtained by normalizing the sediment-transport measurements plotted in figure 

6B against cumulative sand flux predicted for each time interval, as a function of wind speed, by the transport equation of Dong and 

others (2003). Gray vertical bars indicate times of vegetation surveys. B, Direct measurements of eolian sediment transport obtained 

from sampled mass collected in Big Spring Number Eight (BSNE) traps divided by the number of days over which it accumulated. Error 

bars factor in a 70–130-percent efficiency range for BSNE traps (Goossens and others, 2000). C, Wind speed, expressed as daytime 

(06:00–18:00) and nighttime (18:00–06:00) averages of 4-minute data. D, Daily rainfall summed from 4-minute measurements. Gray-shaded 

regions in figures 6C and 6D indicate data from a weather station at North Teesto (fig. 1) during instrument malfunction at study site 7.
Results 9

W Sp Su F

W Sp Su F

W Sp Su F

A

Year day, 2011

Daily rainfall, in millimeters

Daily sediment transport,

in grams per centimeter

trap width

B

Diurnal wind speed,

in meters per second

C

D

Year day, 2012

W Sp Su F

Sediment mobility

50 100 150 200 250 300 350

5

10

15

20

25

30

35

50 100 150 200 250 300 350

2

4

6

8

10

12

14

16

50 100 150 200 250 300 350

5

10

15

20

25

30

35

40

50 100 150 200 250 300 350

10 -5

10

10

10-3

-2

-4

W Sp Su F

W Sp Su F W Sp Su F

W Sp Su F

10 -6

50 100 150 200 250 300 350

50 100 150 200 250 300 350

50 100 150 200 250 300 350

50 100 150 200 250 300 350

Figure 7. Eolian sediment mobility and transport, wind speed, and rainfall measured at study site 7 in 2011 and 2012. A, Sediment 

mobility, in dimensionless units obtained by normalizing the sand-transport measurements plotted in figure 7B against cumulative sand 

flux predicted for each time interval, as a function of wind speed, by the transport equation of Dong and others (2003). Gray vertical bars 

indicate times of vegetation surveys. Note that vertical scale of figure 7A encompasses one order of magnitude more than does the 

scale in figure 6A. B, Direct measurements of eolian sediment transport obtained from sampled mass collected in Big Spring Number 

Eight (BSNE) traps divided by the number of days over which it accumulated. Error bars factor in a 70–130-percent efficiency range for 

BSNE traps (Goossens and others, 2000). Beginning in winter 2011, sand-transport measurements probably were artificially low owing to 

tumbleweed accumulating at the upwind side of sand-trap enclosure. C, Wind speed, expressed as daytime (06:00–18:00) and nighttime 

(18:00–06:00) averages of 4-minute data. D, Daily rainfall summed from 4-minute measurements.
10 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

A

B

C

B

Winter

2010

Summer

2010

Winter

2011

Summer

2011

C

Mean basal gap length,

in centimeters

A

Vegetation cover, in percent

Russian thistle (annual)

Other annuals Perennials

5

10

15

20

25

30

35

Cumulative gap length,

in percent

20

40

60

80

100

500

1,000

1,500

2,000

Winter

2012

Figure 8. Localities in and near the study area (fig. 1) where an 

intense monsoon rainstorm occurred on the evening of July 31, 

2010. A, Gullies more than 1 m deep incised into a graded gravel road, 

approximately 0.5 km east of the study area. B, Streambed of Teesto 

Wash near study site 9, with ripple structures and still-damp sediment 

indicating recent flow. C, Gullies incised into eolian sand near study 

site 4.

Figure 9. Variations in vegetation abundance and species 

assemblage. A, Vegetation cover, with measurements from 

circular plots within pods at all 11 study sites (see fig. 1C for 

locations) combined for each of five biannual surveys. B, 

Cumulative gap length where bare, open sand was present 

on linear transects of each pod (percentage of total transect 

length). Boxes span interquartile range of data collected at all 11 

study sites; horizontal line through each box is median. Circles, 

outlier points with values more than 1.5 times interquartile range; 

bars, highest and lowest non-outlier points. C, Mean basal gap 

length (distance between plant bases; Herrick and others, 2005) 

measured on linear transects of each pod. 
Results 11

Downwind of wash Upwind of wash

10

20

30

40

50

60

70

Vegetation cover, in percent

B

A

1 2 5 7 11 8 9 10

Vegetation cover, in percent

1 11 8 10

MARCH 2010

AUGUST 2010

10

20

30

40

50

60

70

MARCH 2011

AUGUST 2011

Downwind of wash Upwind of wash

2 3 4 5 6 7 9

3 4 6

Site number

C

Vegetation cover, in percent

1 3 5 7 11 9

10

20

30

40

50

60

70

MARCH 2012

Downwind of wash Upwind of wash

2 4 6 8 10

Figure 10. Vegetation cover by study site, showing abundance in March and August surveys in A, 2010, B, 2011, and C, March 2012.
12 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

A B

C D

E F

Figure 11. Study area in the Navajo Nation (fig. 1), showing contrast between August vegetation cover during a year with near-normal 

rainfall (2010) and a year with below-average rainfall (2011). A, Study site 1 in August 2010. B, Study site 1 in August 2011. C, Study site 3 

in August 2010. D, Study site 3 in August 2011. E, Study site 8 in August 2010. F, Study site 8 in August 2011.
Results 13

In 2010, vegetation cover increased substantially 

between the surveys in March and those during the summer 

monsoon season (August) of 2010 (figs. 9, 10; table 2). Both 

annual- and perennial-plant cover increased between March 

and August 2010, with perennial growth occurring primarily 

by canopy cover increase on existing plants rather than by 

recruitment of new plants. No similar increase occurred from 

winter to summer during the much drier year 2011. Plant 

cover decreased slightly between March and August 2011, 

even though warm temperatures and longer daylight hours 

typically favor plant growth then (fig. 9A). During the August 

2011 vegetation survey, when monsoon rainfall that year had 

been only 14 percent of what had fallen by the same date 

in 2010, vegetation cover was notably less than in August 

2010 (fig. 11). Changes in cumulative canopy gap length (fig. 

9B) largely reflected the increase and subsequent decrease 

in vegetation abundance during 2010 and 2011. Substrate 

measurements indicated no substantial change in biologic soil 

crust or rock area, and little change in accumulated leaf litter 

that factor into the cumulative-gap-length calculation, and 

most study sites had >95% sand substrate at each survey (fig. 

12). Leaf litter was somewhat more abundant in 2011 than in 

2010, as expected, given the abundant vegetation in summer 

2010 that had begun to die off by 2011; nevertheless, leaf litter 

accounted for < 3 percent of substrate area at most sites, even 

in the surveys when it was most abundant. As of March 2012, 

vegetation cover apparently had increased slightly relative to 

that of summer 2011 (table 2), although the amount of increase 

was within the measurement uncertainty (15.9±0.79 percent 

in August 2011, in comparison with 16.5±0.83 percent in 

March 2012). Because perennial-plant cover remained nearly 

constant between summer 2011 and winter 2012 (fig. 9; table 

2), an increase in vegetation in winter 2012 could have been 

caused by new growth of annual plants, dominantly stickleaf 

(Mentzelia pumila). This increase in annuals reduced the mean 

basal gap length, although cumulative gap length continued to 

increase, reflecting a steady increase in bare sand area since 

summer 2010 (fig. 9). The substantial vegetation growth during the 2010 summer monsoon season was accompanied by 

a disproportionately greater increase in annual plants relative 

to perennials (fig. 9A). This increase in annual plants also was 

reflected in the decrease in mean basal gap lengths between 

winter and summer 2010 (fig. 9C)—transects intersect more 

plant bases after new annual plants have germinated. Basal 

gap length decreased in 2011 relative to 2010 as annual plants 

died, because annuals did not germinate extensively during the 

very dry summer of 2011. 

Invasive Russian thistle was by far the most abundant 

annual plant in the study area. In the first four surveys, Russian thistle composed 100 percent (March 2010), 70 percent 

(August 2010), 96 percent (March 2011), and 93 percent 

(August 2011) of the total annual-plant cover. After the 2010 

monsoon rains, total vegetation cover increased by a factor of 

2.3, whereas Russian thistle increased by a factor of nearly 15. 

The abundance and rapid increase of Russian thistle during 

2010 likely interfered with the capacity of the BSNE traps 

annual plants desert twinbugs (Dicoria canescens), doveweed 

(Croton texensis), Plains spring parsley (Cymopterus acaulis), 

and bindweed heliotrope (Heliotropium convolvulaceum). 

Nonnative plants Russian thistle (Salsola sp.), an annual, and 

silverleaf nightshade (Solanum elaeagnifolium), a perennial, 

were abundant in several of the surveys, particularly in August 

2010 (table 4). 

Table 1. Plant varieties identified in the study area near Teesto 

Wash, Navajo Nation, Arizona.

[Some surveys also noted unidentified plants that are omitted from this 

list but were recorded as unidentified annual or perennial grasses, forbs, or 

shrubs]

Alkali sacoton (Sporobolus airoides)

Basin wildrye (Leymus cinereus)

Bindweed heliotrope (Heliotropium convolvulaceum)

Dicoria (Dicoria canescens)

Doveweed (Croton texensis)

Ephedra (Ephedra sp.)

Galleta grass (Pleuraphis jamesii)

Giant dropseed (Sporobolus giganteus)

Globemallow (Sphaeralcea sp.)

Grama grass (Bouteloua sp.)

Greene’s rabbitbrush (Chrysothamnus greenei)

Indian ricegrass (Oryzopsis hymenoides)

Milkvetch (Astragalus sp.)

Milkweed (Asclepias sp.)

Mojave indigobush (Psorothamnus arborescens)

Narrowleaf yucca (Yucca angustissima)

Pigweed (Amaranthus sp.)

Plains spring parsley (Cymopterus acaulis)

Purple three-awn (Aristida purpurea)

Rabbitbrush (Ericameria nauseosus)

Russian thistle (Salsola sp.)

Saltbush (Atriplex canescens)

Sand dropseed (Sporobolus cryptandrus)

Sand verbena (Abronia fragrans)

Sandhill muhly (Muhlenbergia pungens)

Silverleaf nightshade (Solanum elaeagnifolium)

Snakeweed (Gutierrezia sarothrae)

Spike dropseed (Sporobolus contractus)

Stickleaf (Mentzelia pumila)

Unidentified aster (Asteraceae family)

Wire lettuce (Stephanomeria pauciflora)
14 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

to collect eolian sediment. By winter 2011, Russian thistle 

had died and produced abundant wind-mobile tumbleweed 

that accumulated in thick piles at the upwind side of the 

fence enclosing the sand traps, apparently inhibiting sand 

movement locally until the tumbleweed was removed during 

monthly maintenance visits. These conditions likely affected 

the relation between our measurements of vegetation cover 

and sand mobility. Loose Russian-thistle debris (tumbleweed) 

was abundant enough in 2011 and 2012 to warrant including 

it as a separate category in measurements of ground cover; at 

many study sites it covered 1–3 percent or more of the ground 

(tables 5–7). Canopy gap length corresponded well in 2010 to 

sand mobility as plant cover grew between March and August 

and as several dry years transitioned into the wetter year 2010 

(fig. 9). However, even though plant cover in summer 2011 

was only half that in summer 2010, measured sand transport 

did not increase correspondingly, possibly as an artifact of 

antecedent Russian thistle abundance, such that tumbleweed 

that grew during the 2010 monsoon rains interfered with sand 

collection in 2011 and even into 2012. 

In contrast to the previous four surveys, the fifth survey 

(March 2012) showed Russian thistle composing only 32 

Substrate composition, in percent Substrate composition, in percent

A

B

Sand

Rock

Litter/manure

Biologic soil crust

20

40

60

80

100

1 11 8 10

20

40

60

80

100

1 11 8 10

Downwind of wash Upwind of wash

Downwind of wash Upwind of wash

Site number

Site number

2 3 4 5 6 7 9

2 3 4 5 76 9

Substrate composition, in percent

D

20

40

60

80

100 Downwind of wash Upwind of wash

1 11 8 10

Substrate composition, in percent

C

20

40

60

80

100 Downwind of wash Upwind of wash

1 11 8 10

Site number

Site number

2 3 4 5 6 7 9

2 3 4 5 6 7 9

Substrate composition, in percent

20

40

60

80

100 Downwind of wash Upwind of wash

1 11 8 10

Site number

E

2 3 4 5 6 7 9

Figure 12. Substrate composition within circular plots of each pod, in A, March 2010; B, August 2010; C, March 2011; D, August 2011; 

and E, March 2012.
Discussion 15

percent of annual-plant cover (fig. 9), with the rest made up 

of stickleaf and several other varieties of annual forbs (table 

7). The winter 2012 survey was the only time during the study 

interval when no living Russian thistle was observed in the 

study area—all Russian thistle plants included in the survey 

(and others outside of the survey pods) were dead, and no 

green seedlings were observed, whereas live green seedlings 

of other annual plants, notably stickleaf, were abundant. 

Discussion 

The data presented here reflect conditions at the upwind 

edge of a dune field. In other, nearby areas with rapidly 

migrating sand dunes devoid or nearly devoid of vegetation, 

sand mobility and transport likely are much greater than in 

our study area. We have omitted such terrain from our study 

because rapid dune migration (more than 30 m during spring 

2011; Redsteer and others, 2011) makes it impossible to 

deploy equipment in the field or to reoccupy the same sites 

for vegetation measurements. Instead, the present study has 

focused on conditions within a landscape where dunes are 

currently stable enough for people to live, work, and raise livestock. Relations discussed among vegetation cover and eolian 

sediment transport and erodibility on this Navajo Nation 

landscape are highly relevant also to other areas of the world 

with similar environmental problems (for example, Kurosaki 

and others, 2011; Okin and others, 2011).

Relative abundance of annual and perennial plants exerts 

an important control on eolian sand mobility and thus on 

landscape stability (Urban and others, 2009; Munson and others, 2011). Annual plants can germinate, mature, and disperse 

seeds with only one season of good rainfall, as occurred in 

the study area between March and August 2010 in response 

to adequate monsoon rains (tables 3, 4; figs. 9, 10). However, 

maintenance of and increase in perennial-plant cover requires 

sufficient moisture in multiple consecutive seasons, not only 

during the summer monsoon. Perennial plants generally have 

stiffer, more durable stems and roots and accumulate more leaf 

litter around their bases, protecting the land surface from wind 

erosion more efficiently than do annual plants (Belnap and 

others, 2009; Okin and others, 2011). Therefore, although a 

year with good monsoon rains and abnormally dry conditions 

in other seasons would cause short-term annual-plant growth, 

such as we measured in 2010, it would not reduce eolian sediment mobility in the long term because it would not enhance 

long-term growth of perennials. The disproportionate increase 

of such annuals as Russian thistle from a good summer monsoon season, such as in 2010 (fig. 9A), is unlikely to increase 

landscape stability. The windy season of the southwestern 

United States occurs in early spring before most annual plants 

have established. For this reason, and also because invasive 

exotic plants germinate earlier and crowd out slower-growing 

native plants, using water that otherwise could be available 

to perennials, the proliferation of Russian thistle may actually decrease landscape stability. Although both annual and 

perennial plants increased during the wetter summer of 2010, 

decreasing sand mobility well into the following year (figs. 6, 

7), the subsequent loss of even perennial-plant cover in a dry 

year, such as occurred during 2011 (fig. 9A), poses a substantial risk to landscape stability in a setting prone to wind erosion. Previous research has shown that perennial-plant cover 

also has decreased elsewhere on the Colorado Plateau as mean 

annual temperatures have risen and precipitation has decreased 

Table 2. Summary of major site characteristics measured in the study area near Teesto Wash, Navajo Nation, Arizona.

[Measurement uncertainty is estimated to be 5 percent of each value given below]

Winter 

2010

Summer 

2010

Winter 

2011

Summer 

2011

Winter 

2012

Total vegetation cover, in percent of area surveyed 14.1 32.6 19.4 15.9 16.5

Total Russian-thistle cover, in percent of area surveyed 0.37 4.30 2.64 1.36 0.74

Total other annual-plant cover, in percent of area surveyed 0 1.88 0.10 0.10 1.53

Total perennial-plant cover, in percent of area surveyed 13.7 26.4 16.7 14.4 14.2

Cumulative gap length, in centimeters, as median value for 11 sites 83.7 61.3 64.7 64.6 77.1

Basal gap length, in centimeters, as median of mean values for 11 sites 571 143 286 444 267

Total sand substrate, in percent of area surveyed 96.4 94.3 93.7 92.9 92.1

Total rock substrate, in percent of area surveyed 2.29 2.74 2.57 2.51 4.35

Total leaf litter substrate, in percent of area surveyed 0.30 0.68 2.10 2.84 2.56

Total biologic-soil-crust substrate, in percent of area surveyed 0.96 2.29 1.61 1.73 0.96
16 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

over the past several decades, contributing to increased eolian 

sediment transport (Munson and others, 2011).

Among the 11 study sites where vegetation and substrate 

assemblage were measured, some differences were apparent between the sites upwind of Teesto Wash (sites 8–10; fig. 

1C) and those downwind of the wash. Study sites 9 and 10 

consistently had the lowest proportions of open sand substrate, with more area than at other sites occupied by rock and, 

especially at site 9, biologic soil crust (fig. 12). The greater 

proportion of open sand substrate at study sites downwind of 

the wash is consistent with observations from aerial photography of windblown sand originating from the ephemerally 

flowing streambed of Teesto Wash and moving downwind 

(figs. 1B, 1C). We infer that eolian sand thus effectively covers rock substrate and inhibits the growth of biologic crust 

downwind (northeast) of the wash. The sensitive organisms 

that compose biologic soil crust do not thrive when constantly 

abraded or buried by windblown sand, and extensive biologic 

crust growth is more commonly associated with areas where 

little eolian sand supply and transport occur (Lancaster, 1994; 

Draut, 2011, 2012). Although study site 8 is also upwind of the 

wash, ground cover there differs from that at other study sites 

because site 8 is affected strongly by livestock activity. Study 

site 8 is located just north of a water cistern visited frequently 

by cattle and horses (figs. 11E, 11F). This site had less overall 

plant diversity and less native-plant cover than did most other 

study sites, and instead contained abundant invasive Russian 

thistle and silverleaf nightshade (figs. 11E, 11F; tables 3–6). 

In the August 2010 survey, those two nonnative plant species accounted for most of the vegetation at study site 8, with 

Russian thistle and silverleaf nightshade composing 43 and 23 

percent, respectively, of the total vegetation cover there (table 

4). The disproportionately high abundance of those two plant 

types is attributed to livestock preferentially grazing on other, 

native plant species, and the ease with which Russian thistle 

and silverleaf nightshade colonize disturbed areas. Although 

livestock may eat Russian thistle when the plant is young and 

small, mature Salsola is thorny and unpalatable. Silverleaf 

nightshade is toxic to animals and is considered a noxious 

weed in many states, including Arizona, owing to its rapid 

spread in disturbed, sandy soils (Huisinga and others, 2006).

Most climate models project that the southwestern 

United States will become increasingly warm and dry during 

the 21st century (for example, Seager and others, 2007a, b) 

and some suggest that intense storms and associated flooding 

may increase (Trenberth, 1998). In such a scenario, perennial 

streamflow would continue to decline on Navajo lands (Redsteer and others, 2010a), whereas stronger, more frequent episodic floods are possible. Because dry streambeds are sources 

of eolian sediment (fig. 1B), flash floods during storms could 

supply additional material that would be entrained by wind 

the following spring (cf. Muhs and Holliday, 1995; Lancaster, 

1997; Clarke and Rendell, 1998; Bullard and McTainsh, 2003; 

Han and others, 2007). Such altered patterns of rainfall and 

streamflow could further increase sediment supply into the 

dunes downwind of dry streambeds that have become common 

on the Navajo Nation since the 1950s (Redsteer and others, 

2010b). Increased eolian sediment transport in springtime also 

could destabilize vegetation that initially thrived under the 

previous fall monsoon rain, because windblown sand damages plants by abrasion and burial (Okin and others, 2006). We 

propose that a negative feedback cycle could develop whereby 

the summer–fall monsoon rain that promotes plant growth also 

supplies ephemeral washes with new sand, which damages 

those plants once it is mobilized by wind. 

Increased eolian sand transport and dune activity in such 

a future climate regime would further compromise living conditions for those on the Navajo Nation, as well as elsewhere 

in the southwestern United States. Because many Navajo 

residents not only have strong traditional ties to these lands but 

also lack the economic means to relocate elsewhere, a future 

combination of climate change, greater sediment mobility, and 

growth of invasive plants that neither stabilize dunes nor serve 

a useful purpose for people or livestock would negatively 

impact residents in the long term.

Implications for the Rocky Mountains 

Snowpack

Eolian sediment transport in northeastern Arizona has 

consequences not only for human health and infrastructure but 

also for the snowpack in the Rocky Mountains of Colorado, 

on which millions of people depend for water supply. Satellite imagery has shown dust plumes originating repeatedly 

from Navajo lands in and near the study area during the time 

interval covered by this study (for example, fig. 13; U.S. Geological Survey, 2012). Windborne dust from the southwestern 

Colorado Plateau is known to settle on snow in the southern 

Rockies, reducing its albedo and leading to earlier spring melting (Painter and others, 2007, 2010; Colorado Dust-on-Snow 

Program, 2011; Phillips and Doesken, 2011). 

Accelerated snowmelt poses a concern for resource managers, who anticipate that the demand for water will increase 

as warmer, drier conditions prompt a shift from snowfall 

toward rainfall and increase eolian sediment transport from the 

Colorado Plateau. This concern is particularly great during La 

Niña phases of the ENSO cycle—in La Niña years, northeastern Arizona generally sees higher wind velocities and less 

rainfall than during El Niño phases (Enloe and others, 2004; 

Phillips and Doesken, 2011), and as the data from this study 

suggest, less vegetation cover to stabilize sandy soils. Though 

dominated by very fine sand, the airborne sediment mobilized 

from our study area contains abundant silt and some clay-size 

material (fig. 14), indicating that sediment in the vicinity of 

the study area is certainly fine enough to be transported great 

distances downwind toward the Rocky Mountains.

Previous studies have indicated a link between strong 

winds in northeastern Arizona and dust events in the southern 

Rockies, with a daily average wind velocity higher than 6.7 

m/s proposed as a threshold value for dust events (Phillips and 

Doesken, 2011), because dust particles commonly are mobilized 
Discussion 17

by the impact of saltating sand grains (for example, Bagnold, 

1941). The high springtime sediment transport and mobility 

measured in our study area in 2009 and 2010 are broadly consistent with the dust-on-snow deposition monitored in the San 

Juan Range of the southern Rocky Mountains (fig. 1A), where 

dust-on-snow mass was greater in spring 2009 than in any of the 

previous 7 years (Skiles and others, 2011). Making more specific connections between trends in eolian sand mobility in our 

study area and dust deposition in the southern Rocky Mountains 

is challenging because within the 350 km between the study 

area and the nearest snowpack downwind where dust events are 

recorded is such a large source area that even with a substantial 

reduction in sediment mobility in the vicinity of our study area, 

such as after substantial plant growth in a year with adequate 

rainfall, wind could still supply ample sediment to the San Juan 

Range. A longer record from the study area and elsewhere may 

clarify the connections between source-area eolian events and 

dust deposition in the mountains downwind.

Tuba City

Leupp

Flagstaff

Chinle

Four Corners

Cortez

Dust plumes

UT CO

AZ NM

Study area

36° 

37° 

110° 109° 

35° 

111°

Figure 13. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite image, showing eolian dust plumes that originated in 

northeastern Arizona, within the Navajo Nation, on the afternoon of May 29, 2011. From National Aeronautics and Space Administration, 

modified and posted online by the U.S. Geological Survey (2012).
18 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Conclusions

On the Navajo Nation, decreasing perennial streamflow 

and warming, drying trends have led to eolian sediment mobilization that affects air quality, housing, and transportation 

and potentially reduces the albedo of the Rocky Mountains 

snowpack downwind. Initial results of an intended long-term 

monitoring program in a 0.2-km2

 study area near Teesto Wash 

on the southern Navajo Nation indicate that sand mobility 

decreased substantially as one year (2010) with near-normal 

monsoon rainfall somewhat abated a decade-long drought, 

temporarily doubling vegetation cover. Perennial plants that 

grew during the same year with adequate monsoon rainfall 

0.1 10 100 1000

5/3/10-1

5/3/10-2

5/3/10-3

5/3/10-4

0.1 10 100 1000

6/3/10-1

6/3/10-2

6/3/10-3

6/3/10-4

0.1 10 100 1000

5/3/11-1

5/3/11-2

5/3/11-3

5/3/11-4

0.1 10 100 1000

6/15/11-1

6/15/11-2

6/15/11-3

6/15/11-4

5

10

15

0.1 10 100 1000

5/1/09-1

5/1/09-2

5/1/09-3

5/1/09-4

0.1 10 100 1000

4/2/10-1

4/2/10-2

4/2/10-3

4/2/10-4

5

10

15

5

10

15

5

10

15

5

10

15

5

10

15

Volume, in percent Volume, in percent Volume, in percent Volume, in percent Volume, in percent Volume, in percent

A

B

C

D

E

F

Grain size, in microns

CLAY SILT SAND

CLAY SILT SAND

CLAY SILT SAND

CLAY SILT SAND

CLAY SILT SAND

CLAY SILT SAND

1

1

1

1

1

1

Figure 14. Particle-size data for 24 selected samples collected in Big Spring Number Eight (BSNE) sediment traps within the study 

area (fig. 1). All samples were obtained during spring, when wind speed is typically highest in this region. Samples were collected on A,

May 1, 2009; B, April 2, 2010; C, May 3, 2010; D, June 3, 2010; E, May 3, 2011; and F, June 15, 2011. Numbers 1–4 after sample date indicate 

position of BSNE trap from which sample was collected, where 1 is uppermost and 4 is lowermost. 
References Cited 19

died off rapidly during a subsequent dry year (2011). The 

proportion of bare, open sand area increased steadily after 

the short-term vegetation growth of summer 2010 began to 

die. Measurements in the study area have shown substantially 

greater vegetation cover during a year when the ENSO cycle 

was in the El Niño phase than during several years in the La 

Niña phase. Isolated seasonal increases in rainfall will not 

improve landscape stability in the long term because a sustained increase in perennial-plant cover, more effective than 

annual plants at stabilizing sand against wind erosion, requires 

multiple consecutive seasons of adequate rain. Climate projections suggest that warmer, drier conditions during the coming 

decades could potentially enhance eolian sediment supply 

after flash floods in otherwise dry, ephemeral washes. Such 

conditions could combine to decrease vegetation cover and 

increase eolian sediment transport and dune activity, worsening the present challenges to people living in this region.

Acknowledgments

This study was supported by the U.S. Geological Survey. 

Research was conducted with permission from the Navajo 

Nation Department of Minerals, the Navajo Nation Historic 

Preservation Office, and the Navajo Nation Water Management Branch. We also are indebted to the Biggambler family 

for providing room in their grazing land for this study. Leanna 

Begay and Arnold Clifford provided information on plant 

species within the Navajo Nation. Particle-size analyses were 

performed by Harland Goldstein of the USGS Geology and 

Environmental Change Science Center. The cover photograph 

was taken by Jon Mason of the USGS Flagstaff Science 

Center. Finally, we thank Daniel Muhs (USGS) and Melissa 

McMaster (National Park Service) for their constructive 

reviews of the manuscript, and George Havach (USGS) for his 

editorial comments.

References Cited

Anderson, R.S., and Hallet, B., 1986, Sediment transport 

by wind—toward a general model: Geological Society of 

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Appendix 1. Supplementary Information
24 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.

[Coverage is given in terms of area and percentage within five circles of radius 3 m, as shown in 

figure 3]

Site 1

Vegetation Area, in square 

meters Percentage

Unidentified perennial grass 5.51 3.90

Mojave indigobush (Psorothamnus arborescens) 3.25 2.30

Snakeweed (Gutierrezia sarothrae) 2.32 1.64

Rabbitbrush (Ericameria nauseosus) 0.71 0.50

Unidentified aster (Asteraceae family) 0.28 0.20

Saltbush (Atriplex canescens) 0.14 0.10

Unidentified shrub, dead 0.14 0.10

Narrowleaf yucca (Yucca angustissima) 0.06 0.04

Russian thistle (Salsola sp.) 0.03 0.02

Total vegetation cover 12.4 8.8

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 91.4

Mean basal gap length, in centimeters 1,000
Appendix 1. Supplementary Information 25

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 2

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 11.3 8.00

Snakeweed (Gutierrezia sarothrae) 4.24 3.00

Unidentified perennial grass 2.54 1.80

Unidentified shrub, dead 1.58 1.12

Rabbitbrush (Ericameria nauseosus) 1.56 1.10

Basin wildrye (Leymus cinereus) 0.14 0.10

Russian thistle (Salsola sp.) 0.14 0.10

Total vegetation cover 21.5 15.2

Substrate Area, in square 

meters Percentage

Sand 141 99.9

Rock 0.08 0.06

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 89.5

Mean basal gap length, in centimeters 1,000

Site 3

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 11.5 8.10

Rabbitbrush (Ericameria nauseosus) 2.83 2.00

Unidentified perennial grass 2.77 1.96

Unidentified shrub, dead 1.19 0.84

Snakeweed (Gutierrezia sarothrae) 0.96 0.68

Russian thistle (Salsola sp.) 0.45 0.32

Total vegetation cover 19.7 13.9

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 75.2

Mean basal gap length, in centimeters 222
26 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 4

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 16.1 11.4

Snakeweed (Gutierrezia sarothrae) 1.75 1.24

Russian thistle (Salsola sp.) 1.05 0.74

Unidentified perennial grass 0.62 0.44

Rabbitbrush (Ericameria nauseosus) 0.51 0.36

Unidentified shrub, dead 0.14 0.10

Total vegetation cover 20.2 14.3

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 81.4

Mean basal gap length, in centimeters 500

Site 5

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 11.3 8.00

Mojave indigobush (Psorothamnus arborescens) 5.94 4.20

Snakeweed (Gutierrezia sarothrae) 3.96 2.80

Unidentified perennial grass 0.31 0.22

Unidentified shrub, dead 0.14 0.10

Russian thistle (Salsola sp.) 0.08 0.06

Total vegetation cover 21.7 15.4

Substrate Area, in square 

meters Percentage

Sand 140 99.3

Rock 1.02 0.72

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 83.8

Mean basal gap length, in centimeters 500
Appendix 1. Supplementary Information 27

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 6

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 9.19 6.50

Rabbitbrush (Ericameria nauseosus) 4.24 3.00

Snakeweed (Gutierrezia sarothrae) 2.21 1.56

Unidentified perennial grass 1.13 0.80

Unidentified shrub, dead 0.85 0.60

Russian thistle (Salsola sp.) 0.74 0.52

Total vegetation cover 18.4 13.0

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0.03 0.02

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 83.7

Mean basal gap length, in centimeters 500

Site 7

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 23.9 16.9

Mojave indigobush (Psorothamnus arborescens) 10.0 7.10

Unidentified perennial grass 1.19 0.84

Russian thistle (Salsola sp.) 0.28 0.20

Snakeweed (Gutierrezia sarothrae) 0.25 0.18

Saltbush (Atriplex canescens) 0.20 0.14

Total vegetation cover 35.9 25.4

Substrate Area, in square 

meters Percentage

Sand 133 93.9

Rock 8.65 6.12

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 81.9

Mean basal gap length, in centimeters 1,000
28 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 8

Vegetation Area, in square 

meters Percentage

Unidentified perennial grass 3.39 2.40

Russian thistle (Salsola sp.) 2.69 1.90

Snakeweed (Gutierrezia sarothrae) 1.72 1.22

Total vegetation cover 7.80 5.52

Substrate Area, in square 

meters Percentage

Sand 141 99.4

Rock 0.11 0.08

Leaf litter 0.71 0.50

Biologic soil crust 0 0

Total gap length, in percent 95.8

Mean basal gap length, in centimeters 2,000

Site 9

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 12.2 8.60

Undifferentiated shrubs, live 6.22 4.40

Unidentified shrubs, dead 3.39 2.40

Rabbitbrush (Ericameria nauseosus) 0.42 0.30

Unidentified perennial grass 0.06 0.04

Snakeweed (Gutierrezia sarothrae) 0.03 0.02

Total vegetation cover 22.3 15.8

Substrate Area, in square 

meters Percentage

Sand 111 78.4

Rock 14.4 10.2

Leaf litter 1.13 0.80

Biologic soil crust 15.0 10.6

Total gap length, in percent 69.1

Mean basal gap length, in centimeters 571
Appendix 1. Supplementary Information 29

Table 3. Vegetation cover and substrate measured in March 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 10

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 7.92 5.60

Mojave indigobush (Psorothamnus arborescens) 4.67 3.30

Unidentified shrubs, dead 0.85 0.60

Snakeweed (Gutierrezia sarothrae) 0.28 0.20

Unidentified perennial grass 0.11 0.08

Total vegetation cover 13.8 9.78

Substrate Area, in square 

meters Percentage

Sand 129 91.1

Rock 11.3 8.00

Leaf litter 1.33 0.94

Biologic soil crust 0 0

Total gap length, in percent 88.8

Mean basal gap length, in centimeters 489

Site 11

Vegetation Area, in square 

meters Percentage

Snakeweed (Gutierrezia sarothrae) 0.57 0.40

Unidentified perennial grass 0.08 0.06

Mojave indigobush (Psorothamnus arborescens) 3.68 2.60

Unidentified shrubs, dead 1.44 1.02

Undifferentiated shrubs, live 19.8 14.0

Russian thistle (Salsola sp.) 0.25 0.18

Total vegetation cover 25.8 18.3

Substrate Area, in square 

meters Percentage

Sand 140 98.9

Rock 0 0

Leaf litter 1.56 1.10

Biologic soil crust 0 0

Total gap length, in percent 75.3

Mean basal gap length, in centimeters 571
30 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area near 

Teesto Wash, Navajo Nation, Arizona.

[Coverage is given in terms of area and percentage within five circles of radius 3 m, as shown in figure 3]

Site 1

Vegetation Area, in square 

meters Percentage

Alkali sacoton (Sporobolus airoides) 11.5 8.10

Mojave indigobush (Psorothamnus arborescens) 3.78 2.68

Russian thistle (Salsola sp.) 3.78 2.68

Plains spring parsley (Cymopterus acaulis) 1.48 1.05

Indian ricegrass (Oryzopsis hymenoides) 1.45 1.03

Unidentified shrub, dead 1.27 0.90

Rabbitbrush (Ericameria nauseosus) 1.20 0.85

Sandhill muhly (Muhlenbergia pungens) 0.85 0.60

Stickleaf (Mentzelia pumila) 0.85 0.60

Purple three-awn (Aristida purpurea) 0.71 0.50

Narrowleaf yucca (Yucca angustissima) 0.57 0.40

Dicoria (Dicoria canescens) 0.35 0.25

Doveweed (Croton texensis) 0.18 0.13

Unidentified annual forb 0.14 0.10

Galleta grass (Pleuraphis jamesii) 0.14 0.10

Greene’s rabbitbrush (Chrysothamnus greenei) 0.14 0.10

Snakeweed (Gutierrezia sarothrae) 0.07 0.05

Giant dropseed (Sporobolus giganteus) 0.07 0.05

Sand verbena (Abronia fragrans) 0.07 0.05

Milkweed (Asclepias sp.) 0.07 0.05

Total vegetation cover 28.6 20.3

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0.60 0.43

Biologic soil crust 0 0

Total gap length, in percent 57.3

Mean basal gap length, in centimeters 87
Appendix 1. Supplementary Information 31

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 2

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 6.79 4.80

Unidentified shrub, dead 3.78 2.68

Russian thistle (Salsola sp.) 3.25 2.30

Stickleaf (Mentzelia pumila) 2.69 1.90

Rabbitbrush (Ericameria nauseosus) 1.84 1.30

Indian ricegrass (Oryzopsis hymenoides) 1.41 1.00

Plains spring parsley (Cymopterus acaulis) 1.34 0.95

Sandhill muhly (Muhlenbergia pungens) 1.17 0.83

Alkali sacoton (Sporobolus airoides) 0.99 0.70

Galleta grass (Pleuraphis jamesii) 0.57 0.40

Doveweed (Croton texensis) 0.49 0.35

Snakeweed (Gutierrezia sarothrae) 0.46 0.33

Dicoria (Dicoria canescens) 0.42 0.30

Bindweed heliotrope (Heliotropium convolvulaceum) 0.21 0.15

Unidentified annual forb 0.14 0.10

Wire lettuce (Stephanomeria pauciflora) 0.14 0.10

Total vegetation cover 25.7 18.2

Substrate Area, in square 

meters Percentage

Sand 141 99.9

Rock 0 0

Leaf litter 0.18 0.13

Biologic soil crust 0 0

Total gap length, in percent 65.3

Mean basal gap length, in centimeters 125
32 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 3

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 16.5 11.7

Russian thistle (Salsola sp.) 6.29 4.45

Rabbitbrush (Ericameria nauseosus) 5.02 3.55

Stickleaf (Mentzelia pumila) 2.90 2.05

Sandhill muhly (Muhlenbergia pungens) 2.26 1.60

Giant dropseed (Sporobolus giganteus) 2.23 1.58

Plains spring parsley (Cymopterus acaulis) 1.41 1.00

Unidentified shrub, dead 1.27 0.90

Indian ricegrass (Oryzopsis hymenoides) 0.59 0.42

Doveweed (Croton texensis) 0.57 0.40

Dicoria (Dicoria canescens) 0.30 0.21

Snakeweed (Gutierrezia sarothrae) 0.28 0.20

Galleta grass (Pleuraphis jamesii) 0.18 0.13

Alkali sacoton (Sporobolus airoides) 0.14 0.10

Globemallow (Sphaeralcea sp.) 0.14 0.10

Unidentified annual grass 0.11 0.08

Total vegetation cover 40.2 28.5

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0.14 0.10

Biologic soil crust 0 0

Total gap length, in percent 62.4

Mean basal gap length, in centimeters 121
Appendix 1. Supplementary Information 33

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 4

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 19.4 13.7

Russian thistle (Salsola sp.) 10.6 7.50

Stickleaf (Mentzelia pumila) 9.19 6.50

Rabbitbrush (Ericameria nauseosus) 2.26 1.60

Doveweed (Croton texensis) 1.41 1.00

Silverleaf nightshade (Solanum elaeagnifolium) 1.20 0.85

Bindweed heliotrope (Heliotropium convolvulaceum) 1.15 0.81

Unidentified forb, dead 1.13 0.80

Indian ricegrass (Oryzopsis hymenoides) 0.98 0.69

Plains spring parsley (Cymopterus acaulis) 0.95 0.67

Unidentified annual grass 0.71 0.50

Snakeweed (Gutierrezia sarothrae) 0.57 0.40

Globemallow (Sphaeralcea sp.) 0.49 0.35

Unidentified perennial grasses 0.49 0.35

Dicoria (Dicoria canescens) 0.23 0.16

Sandhill muhly (Muhlenbergia pungens) 0.14 0.10

Unidentified shrubs, dead 0.14 0.10

Spike dropseed (Sporobolus contractus) 0.07 0.05

Galleta grass (Pleuraphis jamesii) 0.04 0.03

Total vegetation cover 51.2 36.2

Substrate Area, in square 

meters Percentage

Sand 141.32 99.96

Rock 0.06 0.04

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 64.0

Mean basal gap length, in centimeters 143
34 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 5

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 13.3 9.40

Stickleaf (Mentzelia pumila) 11.2 7.90

Rabbitbrush (Ericameria nauseosus) 7.63 5.40

Silverleaf nightshade (Solanum elaeagnifolium) 6.29 4.45

Snakeweed (Gutierrezia sarothrae), dead 3.89 2.75

Plains spring parsley (Cymopterus acaulis) 3.82 2.70

Doveweed (Croton texensis) 3.34 2.36

Russian thistle (Salsola sp.) 2.47 1.75

Bindweed heliotrope (Heliotropium convolvulaceum) 1.41 1.00

Unidentified perennial grass 0.85 0.60

Indian ricegrass (Oryzopsis hymenoides) 0.59 0.42

Unidentified annual grass 0.54 0.38

Snakeweed (Gutierrezia sp.) 0.49 0.35

Dicoria (Dicoria canescens) 0.11 0.08

Unidentified annual forb 0.08 0.06

Total vegetation cover 56.0 39.6

Substrate Area, in square 

meters Percentage

Sand 141 100

Rock 0 0

Leaf litter 0 0

Biologic soil crust 0 0

Total gap length, in percent 61.3

Mean basal gap length, in centimeters 267
Appendix 1. Supplementary Information 35

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 6

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 23.5 16.6

Stickleaf (Mentzelia pumila) 11.6 8.20

Russian thistle (Salsola sp.) 10.9 7.70

Plains spring parsley (Cymopterus acaulis) 7.35 5.20

Doveweed (Croton texensis) 3.25 2.30

Rabbitbrush (Ericameria nauseosus) 3.25 2.30

Indian ricegrass (Oryzopsis hymenoides) 1.34 0.95

Unidentified annual forb 1.27 0.90

Unidentified dead plant 0.92 0.65

Sand dropseed (Sporobolus cryptandrus) 0.71 0.50

Giant dropseed (Sporobolus giganteus) 0.14 0.10

Alkali sacoton (Sporobolus airoides) 0.07 0.05

Galleta grass (Pleuraphis jamesii) 0.04 0.03

Total vegetation cover 64.3 45.5

Substrate Area, in square 

meters Percentage

Sand 141.1 99.8

Rock 0 0

Leaf litter 0.28 0.20

Biologic soil crust 0 0

Total gap length, in percent 61.7

Mean basal gap length, in centimeters 148
36 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 7

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 22.3 15.8

Mojave indigobush (Psorothamnus arborescens) 5.94 4.20

Sandhill muhly (Muhlenbergia pungens) 5.09 3.60

Stickleaf (Mentzelia pumila) 4.17 2.95

Russian thistle (Salsola sp.) 3.65 2.58

Plains spring parsley (Cymopterus acaulis) 2.40 1.70

Doveweed (Croton texensis) 2.33 1.65

Giant dropseed (Sporobolus giganteus) 1.41 1.00

Indian ricegrass (Oryzopsis hymenoides) 1.17 0.83

Alkali sacoton (Sporobolus airoides) 0.85 0.60

Unidentified dead plants 0.71 0.50

Sand dropseed (Sporobolus cryptandrus) 0.65 0.46

Unidentified annual grass 0.57 0.40

Ephedra (Ephedra sp.) 0.42 0.30

Saltbush (Atriplex canescens) 0.42 0.30

Dicoria (Dicoria canescens) 0.14 0.10

Snakeweed (Gutierrezia sarothrae) 0.08 0.06

Total vegetation cover 52.3 37.0

Substrate Area, in square 

meters Percentage

Sand 132 93.6

Rock 7.49 5.30

Leaf litter 1.56 1.10

Biologic soil crust 0 0

Total gap length, in percent 48.4

Mean basal gap length, in centimeters 103
Appendix 1. Supplementary Information 37

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 8

Vegetation Area, in square 

meters Percentage

Silverleaf nightshade (Solanum elaeagnifolium) 22.5 15.9

Russian thistle (Salsola sp.) 11.9 8.40

Sand dropseed (Sporobolus cryptandrus) 10.0 7.10

Doveweed (Croton texensis) 6.36 4.50

Unidentified dead plants 0.99 0.70

Unidentified perennial grass 0.57 0.40

Pigweed (Amaranthus sp.) 0.14 0.10

Sandhill muhly (Muhlenbergia pungens) 0.14 0.10

Bindweed heliotrope (Heliotropium convolvulaceum) 0.04 0.03

Total vegetation cover 52.6 37.2

Substrate Area, in square 

meters Percentage

Sand 138 97.7

Rock 0.28 0.20

Leaf litter 2.97 2.10

Biologic soil crust 0 0

Total gap length, in percent 58.7

Mean basal gap length, in centimeters 108
38 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 9

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 17.8 12.6

Rabbitbrush (Ericameria nauseosus) 9.61 6.80

Unidentified annual forbs 6.22 4.40

Stickleaf (Mentzelia pumila) 4.81 3.40

Unidentified dead plants 3.53 2.50

Unidentified dead shrub 1.27 0.90

Doveweed (Croton texensis) 0.95 0.68

Unidentified annual grass 0.68 0.48

Russian thistle (Salsola sp.) 0.52 0.37

Plains spring parsley (Cymopterus acaulis) 0.14 0.10

Globemallow (Sphaeralcea sp.) 0.10 0.07

Total vegetation cover 45.7 32.3

Substrate Area, in square 

meters Percentage

Sand 78.8 55.8

Rock 24.3 17.2

Leaf litter 3.25 2.30

Biologic soil crust 35.0 24.8

Total gap length, in percent 6.28

Mean basal gap length, in centimeters 444
Appendix 1. Supplementary Information 39

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 10

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 15.6 11.0

Stickleaf (Mentzelia pumila) 7.35 5.20

Mojave indigobush (Psorothamnus arborescens) 6.64 4.70

Unidentified dead shrubs 3.11 2.20

Russian thistle (Salsola sp.) 2.12 1.50

Plains spring parsley (Cymopterus acaulis) 1.27 0.90

Unidentified perennial grass 0.85 0.60

Unidentified dead plants 0.71 0.50

Unidentified annual forb 0.42 0.30

Unidentified annual forb (second) 0.42 0.30

Snakeweed (Gutierrezia sarothrae) 0.28 0.20

Indian ricegrass (Oryzopsis hymenoides) 0.14 0.10

Doveweed (Croton texensis) 0.14 0.10

Pigweed (Amaranthus sp.) 0.07 0.05

Milkvetch (Astragalus sp.) 0.07 0.05

Total vegetation cover 39.2 27.7

Substrate Area, in square 

meters Percentage

Sand 130 92.1

Rock 10.5 7.40

Leaf litter 0.71 0.50

Biologic soil crust 0 0

Total gap length, in percent 13.0

Mean basal gap length, in centimeters 666
40 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 4. Vegetation cover and substrate measured in August 2010 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 11

Vegetation Area, in square 

meters Percentage

Unidentified annual forb 14.1 10.0

Stickleaf (Mentzelia pumila) 12.2 8.60

Russian thistle (Salsola sp.) 11.5 8.10

Mojave indigobush (Psorothamnus arborescens) 9.90 7.00

Unidentified annual forb (second) 3.39 2.40

Unidentified dead plants 2.54 1.80

Plains spring parsley (Cymopterus acaulis) 1.34 0.95

Indian ricegrass (Oryzopsis hymenoides) 0.85 0.60

Unidentified perennial grass 0.57 0.40

Bindweed heliotrope (Heliotropium convolvulaceum) 0.35 0.25

Sand dropseed (Sporobolus cryptandrus) 0.14 0.10

Total vegetation cover 56.8 40.2

Substrate Area, in square 

meters Percentage

Sand 139.8 98.9

Rock 0 0

Leaf litter 1.56 1.10

Biologic soil crust 0 0

Total gap length, in percent 61.6

Mean basal gap length, in centimeters 200
Appendix 1. Supplementary Information 41

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.

[Coverage is given in terms of area and percentage within five circles of radius 3 m, as shown in 

figure 3]

Site 1

Vegetation Area, in square 

meters Percentage

Galleta grass (Pleuraphis jamesii) 13.9 9.80

Mojave indigobush (Psorothamnus arborescens) 2.54 1.80

Russian thistle (Salsola sp.) 1.91 1.35

Stickleaf (Mentzelia pumila) 1.63 1.15

Sandhill muhly (Muhlenbergia pungens) 0.85 0.60

Indian ricegrass (Oryzopsis hymenoides) 0.83 0.59

Rabbitbrush (Ericameria nauseosus) 0.71 0.50

Snakeweed (Gutierrezia sarothrae), live 0.61 0.43

Snakeweed (Gutierrezia sarothrae), dead 0.57 0.40

Narrowleaf yucca (Yucca angustissima) 0.42 0.30

Saltbush (Atriplex canescens) 0.42 0.30

Sand dropseed (Sporobolus cryptandrus) 0.20 0.14

Unidentified perennial grass, dead 0.14 0.10

Sand verbena (Abronia fragrans) 0.08 0.06

Unidentified forb 0.07 0.05

Total vegetation cover 24.8 17.6

Substrate Area, in square 

meters Percentage

Sand 139.1 98.4

Rock 0.00 0.00

Leaf litter 2.26 1.60

Biologic soil crust 0.00 0.00

Russian-thistle litter 0.71 0.50

Total gap length, in percent 70.1

Mean basal gap length, in centimeters 133
42 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 2

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 12.6 8.90

Russian thistle (Salsola sp.) 4.59 3.25

Rabbitbrush (Ericameria nauseosus) 3.68 2.60

Sandhill muhly (Muhlenbergia pungens) 3.32 2.35

Indian ricegrass (Oryzopsis hymenoides) 2.12 1.50

Stickleaf (Mentzelia pumila) 1.89 1.34

Snakeweed (Gutierrezia sarothrae), dead 1.70 1.20

Galleta grass (Pleuraphis jamesii) 1.41 1.00

Unidentified shrub, dead 1.27 0.90

Unidentified perennial forb 0.71 0.5

Giant dropseed (Sporobolus giganteus) 0.61 0.43

Snakeweed (Gutierrezia sarothrae), live 0.48 0.34

Total vegetation cover 34.4 24.3

Substrate Area, in square 

meters Percentage

Sand 137 97.0

Rock 0 0

Leaf litter 4.24 3.00

Biologic soil crust 0 0

Russian-thistle litter 2.83 2.00

Total gap length, in percent 79.4

Mean basal gap length, in centimeters 222
Appendix 1. Supplementary Information 43

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 3

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 16.7 11.8

Russian thistle (Salsola sp.) 5.80 4.10

Rabbitbrush (Ericameria nauseosus) 4.03 2.85

Indian ricegrass (Oryzopsis hymenoides) 2.33 1.65

Stickleaf (Mentzelia pumila) 2.12 1.50

Sandhill muhly (Muhlenbergia pungens) 1.84 1.30

Giant dropseed (Sporobolus giganteus) 1.29 0.91

Unidentified plant 0.64 0.45

Galleta grass (Pleuraphis jamesii) 0.57 0.40

Snakeweed (Gutierrezia sarothrae) 0.28 0.20

Total vegetation cover 35.6 25.2

Substrate Area, in square 

meters Percentage

Sand 138 97.8

Rock 0 0

Leaf litter 3.11 2.20

Biologic soil crust 0 0

Russian-thistle litter 4.67 3.30

Total gap length, in percent 52.2

Mean basal gap length, in centimeters 118
44 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 4

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 22.1 15.6

Russian thistle (Salsola sp.) 8.91 6.30

Stickleaf (Mentzelia pumila) 3.24 2.29

Indian ricegrass (Oryzopsis hymenoides) 1.07 0.76

Rabbitbrush (Ericameria nauseosus) 0.85 0.60

Snakeweed (Gutierrezia sarothrae), dead 0.28 0.20

Spike dropseed (Sporobolus contractus) 0.28 0.20

Plains spring parsley (Cymopterus acaulis) 0.03 0.02

Globemallow (Sphaeralcea sp.) 0.03 0.02

Total vegetation cover 36.7 26.0

Substrate Area, in square 

meters Percentage

Sand 139 98.3

Rock 0 0

Leaf litter 2.40 1.70

Biologic soil crust 0 0

Russian-thistle litter 10.3 7.30

Total gap length, in percent 58.6

Mean basal gap length, in centimeters 286
Appendix 1. Supplementary Information 45

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 5

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 10.5 7.40

Mojave indigobush (Psorothamnus arborescens) 9.75 6.90

Stickleaf (Mentzelia pumila) 1.84 1.30

Russian thistle (Salsola sp.) 1.77 1.25

Snakeweed (Gutierrezia sarothrae), live 1.63 1.15

Snakeweed (Gutierrezia sarothrae), dead 0.57 0.40

Unidentified annual forb 0.49 0.35

Unidentified plant 0.42 0.30

Giant dropseed (Sporobolus giganteus) 0.28 0.20

Indian ricegrass (Oryzopsis hymenoides) 0.23 0.16

Silverleaf nightshade (Solanum elaeagnifolium) 0.07 0.05

Unidentified perennial grass 0.03 0.02

Plains spring parsley (Cymopterus acaulis) 0.03 0.02

Total vegetation cover 27.6 19.5

Substrate Area, in square 

meters Percentage

Sand 137 97.1

Rock 0 0

Leaf litter 3.96 2.80

Biologic soil crust 0 0

Russian-thistle litter 5.23 3.70

Total gap length, in percent 67.1

Mean basal gap length, in centimeters 400
46 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 6

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 8.48 6.00

Rabbitbrush (Ericameria nauseosus) 7.21 5.10

Russian thistle (Salsola sp.) 2.32 1.64

Stickleaf (Mentzelia pumila) 2.12 1.50

Sand dropseed (Sporobolus cryptandrus) 0.99 0.70

Giant dropseed (Sporobolus giganteus) 0.98 0.69

Indian ricegrass (Oryzopsis hymenoides) 0.68 0.48

Unidentified annual forb 0.57 0.40

Unidentified perennial forb 0.31 0.22

Rabbitbrush (Ericameria nauseosus), dead 0.28 0.20

Snakeweed (Gutierrezia sarothrae), dead 0.23 0.16

Unidentified plant 0.14 0.10

Grama grass (Bouteloua sp.) 0.08 0.06

Sandhill muhly (Muhlenbergia pungens) 0.07 0.05

Total vegetation cover 24.5 17.3

Substrate Area, in square 

meters Percentage

Sand 139 98.5

Rock 0 0

Leaf litter 1.98 1.40

Biologic soil crust 0 0

Russian-thistle litter 2.40 1.70

Total gap length, in percent 69.1

Mean basal gap length, in centimeters 400
Appendix 1. Supplementary Information 47

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 7

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 13.9 9.80

Russian thistle (Salsola sp.) 4.21 2.98

Mojave indigobush (Psorothamnus arborescens) 3.96 2.80

Galleta grass (Pleuraphis jamesii) 3.39 2.40

Unidentified plant 0.85 0.60

Indian ricegrass (Oryzopsis hymenoides) 0.75 0.53

Sandhill muhly (Muhlenbergia pungens) 0.71 0.50

Ephedra (Ephedra sp.) 0.65 0.46

Giant dropseed (Sporobolus giganteus) 0.64 0.45

Stickleaf (Mentzelia pumila) 0.57 0.40

Sand dropseed (Sporobolus cryptandrus) 0.42 0.30

Saltbush (Atriplex canescens) 0.34 0.24

Snakeweed (Gutierrezia sarothrae) 0.14 0.10

Total vegetation cover 30.5 21.6

Substrate Area, in square 

meters Percentage

Sand 130 92.2

Rock 8.77 6.20

Leaf litter 2.26 1.60

Biologic soil crust 0 0

Russian-thistle litter 6.50 4.60

Total gap length, in percent 52.5

Mean basal gap length, in centimeters 222
48 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 8

Vegetation Area, in square 

meters Percentage

Sand dropseed (Sporobolus cryptandrus) 6.43 4.55

Russian thistle (Salsola sp.) 4.67 3.30

Galleta grass (Pleuraphis jamesii) 1.70 1.20

Unidentified plant 0.99 0.70

Unidentified perennial grass 0.57 0.40

Unidentified perennial forb 0.42 0.30

Silverleaf nightshade (Solanum elaeagnifolium) 0.28 0.20

Unidentified annual forb 0.14 0.10

Indian ricegrass (Oryzopsis hymenoides) 0.06 0.04

Globemallow (Sphaeralcea sp.) 0.06 0.04

Snakeweed (Gutierrezia sarothrae), dead 0.06 0.04

Total vegetation cover 15.4 10.9

Substrate Area, in square 

meters Percentage

Sand 137 96.6

Rock 0.59 0.42

Leaf litter 4.24 3.00

Biologic soil crust 0 0

Russian-thistle litter 1.84 1.30

Total gap length, in percent 75.3

Mean basal gap length, in centimeters 148
Appendix 1. Supplementary Information 49

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 9

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 13.7 9.70

Rabbitbrush (Ericameria nauseosus) 2.26 1.60

Stickleaf (Mentzelia pumila) 1.87 1.32

Unidentified shrub, dead 1.13 0.80

Russian thistle (Salsola sp.) 0.85 0.60

Rabbitbrush (Ericameria nauseosus), dead 0.71 0.50

Grama grass (Bouteloua sp.) 0.49 0.35

Total vegetation cover 21.0 14.9

Substrate Area, in square 

meters Percentage

Sand 100 71.1

Rock 15.8 11.2

Leaf litter 2.90 2.05

Biologic soil crust 22.2 15.7

Russian-thistle litter 2.40 1.70

Total gap length, in percent 41.0

Mean basal gap length, in centimeters 1333

Site 10

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 11.7 8.30

Mojave indigobush (Psorothamnus arborescens) 6.36 4.50

Stickleaf (Mentzelia pumila) 1.98 1.40

Russian thistle (Salsola sp.) 1.41 1.00

Rabbitbrush (Ericameria nauseosus), dead 0.42 0.30

Ephedra (Ephedra sp.), dead 0.42 0.30

Indian ricegrass (Oryzopsis hymenoides) 0.20 0.14

Unidentified shrubs, dead 0.14 0.10

Total vegetation cover 22.7 16.0

Substrate Area, in square 

meters Percentage

Sand 123 86.9

Rock 14.4 10.2

Leaf litter 1.27 0.90

Biologic soil crust 2.83 2.00

Russian-thistle litter 0.71 0.50

Total gap length, in percent 58.5

Mean basal gap length, in centimeters 2000
50 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 5. Vegetation cover and substrate measured in March 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 11

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 17.2 12.2

Russian thistle (Salsola sp.) 4.61 3.26

Stickleaf (Mentzelia pumila) 2.71 1.92

Rabbitbrush (Ericameria nauseosus) 2.26 1.60

Indian ricegrass (Oryzopsis hymenoides) 0.85 0.60

Unidentified forbs 0.37 0.26

Giant dropseed (Sporobolus giganteus) 0.28 0.20

Snakeweed (Gutierrezia sarothrae), dead 0.28 0.20

Sand dropseed (Sporobolus cryptandrus) 0.14 0.10

Unidentified aster (Asteraceae family) 0.08 0.06

Total vegetation cover 28.8 20.4

Substrate Area, in square 

meters Percentage

Sand 137 97.0

Rock 0 0

Leaf litter 4.10 2.90

Biologic soil crust 0.08 0.06

Russian-thistle litter 4.67 3.30

Total gap length, in percent 64.7

Mean basal gap length, in centimeters 444
Appendix 1. Supplementary Information 51

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.

[Coverage is given in terms of area and percentage within five circles of radius 3 m, as shown in 

figure 3]

Site 1

Vegetation Area, in square 

meters Percentage

Unidentified perennial grass, dead 11.3 8.00

Mojave indigobush (Psorothamnus arborescens) 5.51 3.90

Sand dropseed (Sporobolus cryptandrus) 1.84 1.30

Sandhill muhly (Muhlenbergia pungens) 1.41 1.00

Russian thistle (Salsola sp.) 0.92 0.65

Saltbush (Atriplex canescens) 0.57 0.40

Narrowleaf yucca (Yucca angustissima) 0.57 0.40

Rabbitbrush (Ericameria nauseosus) 0.57 0.40

Stickleaf (Mentzelia pumila) 0.42 0.30

Indian ricegrass (Oryzopsis hymenoides) 0.42 0.30

Snakeweed (Gutierrezia sarothrae) 0.39 0.28

Unidentified shrub, dead 0.35 0.25

Alkali sacoton (Sporobolus airoides) 0.28 0.20

Snakeweed (Gutierrezia sp.), dead 0.14 0.10

Total vegetation cover 24.7 17.5

Substrate Area, in square 

meters Percentage

Sand 139 98.0

Rock 0 0

Leaf litter 2.83 2.00

Biologic soil crust 0 0

Russian-thistle litter 0.28 0.20

Total gap length, in percent 79.5

Mean basal gap length, in centimeters 129
52 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 2

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 9.90 7.00

Rabbitbrush (Ericameria nauseosus) 3.11 2.20

Sandhill muhly (Muhlenbergia pungens) 2.97 2.10

Unidentified perennial grass 1.91 1.35

Unidentified shrub, dead 1.13 0.80

Indian ricegrass (Oryzopsis hymenoides) 0.75 0.53

Russian thistle (Salsola sp.) 0.57 0.40

Stickleaf (Mentzelia pumila) 0.51 0.36

Snakeweed (Gutierrezia sarothrae) 0.39 0.28

Giant dropseed (Sporobolus giganteus) 0.35 0.25

Spike dropseed (Sporobolus contractus) 0.21 0.15

Unidentified perennial forb 0.14 0.10

Snakeweed (Gutierrezia sarothrae), dead 0.14 0.10

Unidentified perennial forb, dead 0.06 0.04

Total vegetation cover 22.1 15.7

Substrate Area, in square 

meters Percentage

Sand 138 97.8

Rock 0.85 0.60

Leaf litter 2.26 1.60

Biologic soil crust 0 0

Russian-thistle litter 1.98 1.40

Total gap length, in percent 74.1

Mean basal gap length, in centimeters 400
Appendix 1. Supplementary Information 53

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 3

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 9.61 6.80

Sandhill muhly (Muhlenbergia pungens) 3.68 2.60

Rabbitbrush (Ericameria nauseosus) 2.97 2.10

Russian thistle (Salsola sp.) 2.76 1.95

Unidentified perennial grass 2.33 1.65

Indian ricegrass (Oryzopsis hymenoides) 1.06 0.75

Stickleaf (Mentzelia pumila) 0.85 0.60

Giant dropseed (Sporobolus giganteus) 0.57 0.40

Unidentified shrub, dead 0.14 0.10

Snakeweed (Gutierrezia sarothrae) 0.13 0.09

Spike dropseed (Sporobolus contractus) 0.07 0.05

Total vegetation cover 24.2 17.1

Substrate Area, in square 

meters Percentage

Sand 139 98.2

Rock 0 0

Leaf litter 2.54 1.80

Biologic soil crust 0 0

Russian-thistle litter 2.54 1.80

Total gap length, in percent 64.6

Mean basal gap length, in centimeters 191
54 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 4

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 20.4 14.4

Russian thistle (Salsola sp.) 3.60 2.55

Rabbitbrush (Ericameria nauseosus) 1.15 0.81

Stickleaf (Mentzelia pumila) 1.03 0.73

Indian ricegrass (Oryzopsis hymenoides) 0.49 0.35

Unidentified perennial grass 0.20 0.14

Snakeweed (Gutierrezia sarothrae), dead 0.07 0.05

Globemallow (Sphaeralcea sp.) 0.03 0.02

Total vegetation cover 26.9 19.1

Substrate Area, in square 

meters Percentage

Sand 139 98.0

Rock 0 0

Leaf litter 2.83 2.00

Biologic soil crust 0 0

Russian-thistle litter 3.11 2.20

Total gap length, in percent 70.1

Mean basal gap length, in centimeters 562

 
Appendix 1. Supplementary Information 55

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 5

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 11.3 8.00

Mojave indigobush (Psorothamnus arborescens) 7.35 5.20

Russian thistle (Salsola sp.) 0.75 0.53

Snakeweed (Gutierrezia sarothrae) 0.57 0.40

Snakeweed (Gutierrezia sarothrae), dead 0.42 0.30

Silverleaf nightshade (Solanum elaeagnifolium) 0.37 0.26

Indian ricegrass (Oryzopsis hymenoides) 0.25 0.18

Unidentified perennial grass, dead 0.21 0.15

Giant dropseed (Sporobolus giganteus) 0.14 0.10

Stickleaf (Mentzelia pumila) 0.07 0.05

Unidentified perennial grass 0.04 0.03

Total vegetation cover 21.5 15.2

Substrate Area, in square 

meters Percentage

Sand 134 94.5

Rock 4.38 3.10

Leaf litter 3.32 2.35

Biologic soil crust 0 0

Russian-thistle litter 3.96 2.80

Total gap length, in percent 75.1

Mean basal gap length, in centimeters 571
56 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

 

Site 6

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 9.19 6.50

Rabbitbrush (Ericameria nauseosus) 4.24 3.00

Russian thistle (Salsola sp.) 0.93 0.66

Unidentified perennial grass 0.89 0.63

Snakeweed (Gutierrezia sarothrae) 0.85 0.60

Unidentified shrub, dead 0.71 0.50

Unidentified annual plants, dead 0.57 0.40

Giant dropseed (Sporobolus giganteus) 0.17 0.12

Indian ricegrass (Oryzopsis hymenoides) 0.16 0.12

Snakeweed (Gutierrezia sarothrae), dead 0.14 0.10

Stickleaf (Mentzelia pumila) 0.10 0.07

Total vegetation cover 17.9 12.7

Substrate Area, in square 

meters Percentage

Sand 137 97.2

Rock 1.98 1.40

Leaf litter 1.98 1.40

Biologic soil crust 0 0

Russian-thistle litter 2.33 1.65

Total gap length, in percent 63.8

Mean basal gap length, in centimeters 444
Appendix 1. Supplementary Information 57

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 7

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 9.19 6.50

Rabbitbrush (Ericameria nauseosus) 9.19 6.50

Unidentified perennial grass 1.70 1.20

Russian thistle (Salsola sp.) 1.34 0.95

Unidentified annual plants, dead 0.85 0.60

Sandhill muhly (Muhlenbergia pungens) 0.42 0.30

Saltbush (Atriplex canescens) 0.42 0.30

Sand dropseed (Sporobolus cryptandrus) 0.42 0.30

Snakeweed (Gutierrezia sarothrae) 0.42 0.30

Ephedra (Ephedra sp.) 0.35 0.25

Giant dropseed (Sporobolus giganteus) 0.35 0.25

Indian ricegrass (Oryzopsis hymenoides) 0.28 0.20

Total vegetation cover 25.0 17.7

Substrate Area, in square 

meters Percentage

Sand 126 89.3

Rock 10.7 7.55

Leaf litter 4.52 3.20

Biologic soil crust 0 0

Russian-thistle litter 5.51 3.90

Total gap length, in percent 57.6

Mean basal gap length, in centimeters 400
58 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 8

Vegetation Area, in square 

meters Percentage

Sand dropseed (Sporobolus cryptandrus) 8.62 6.10

Russian thistle (Salsola sp.) 8.34 5.90

Unidentified perennial grass 3.68 2.60

Silverleaf nightshade (Solanum elaeagnifolium) 1.29 0.91

Total vegetation cover 21.9 15.5

Substrate Area, in square 

meters Percentage

Sand 127 90.1

Rock 3.28 2.32

Leaf litter 10.7 7.60

Biologic soil crust 0 0

Russian-thistle litter 0.14 0.10

Total gap length, in percent 88.7

Mean basal gap length, in centimeters 167

Site 9

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 14.6 10.3

Rabbitbrush (Ericameria nauseosus) 2.83 2.00

Russian thistle (Salsola sp.) 0.23 0.16

Unidentified shrub, dead 2.54 1.80

Unidentified perennial forb, dead 0.14 0.10

Stickleaf (Mentzelia pumila) 0.28 0.20

Total vegetation cover 20.6 14.6

Substrate Area, in square 

meters Percentage

Sand 97.7 69.1

Rock 10.2 7.20

Leaf litter 6.64 4.70

Biologic soil crust 26.9 19.0

Russian-thistle litter 2.40 1.70

Total gap length, in percent 34.6

Mean basal gap length, in centimeters 2000
Appendix 1. Supplementary Information 59

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 10

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 8.48 6.00

Rabbitbrush (Ericameria nauseosus) 7.86 5.56

Russian thistle (Salsola sp.) 1.19 0.84

Stickleaf (Mentzelia pumila) 0.57 0.40

Unidentified shrub, dead 0.57 0.40

Unidentified perennial grass 0.03 0.02

Globemallow (Sphaeralcea sp.) 0.03 0.02

Indian ricegrass (Oryzopsis hymenoides) 0.31 0.22

Snakeweed (Gutierrezia sp.) 0.14 0.10

Total vegetation cover 19.2 13.6

Substrate Area, in square 

meters Percentage

Sand 132 93.4

Rock 7.63 5.40

Leaf litter 1.70 1.20

Biologic soil crust 0 0

Russian-thistle litter 2.12 1.50

Total gap length, in percent 51.2

Mean basal gap length, in centimeters 571
60 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 6. Vegetation cover and substrate measured in August 2011 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 11

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 18.5 13.1

Stickleaf (Mentzelia pumila) 1.22 0.86

Russian thistle (Salsola sp.) 1.22 0.86

Indian ricegrass (Oryzopsis hymenoides) 0.62 0.44

Unidentified shrub, dead 0.57 0.40

Rabbitbrush (Ericameria nauseosus) 0.28 0.20

Giant dropseed (Sporobolus giganteus) 0.28 0.20

Unidentified perennial grass, dead 0.17 0.12

Unidentified aster (Asteraceae family) 0.08 0.06

Total vegetation cover 23.0 16.2

Substrate Area, in square 

meters Percentage

Sand 137 96.6

Rock 0 0

Leaf litter 4.81 3.40

Biologic soil crust 0 0

Russian-thistle litter 1.98 1.40

Total gap length, in percent 62.2

Mean basal gap length, in centimeters 500
Appendix 1. Supplementary Information 61

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.

[Coverage is given in terms of area and percentage within five circles of radius 3 m, as shown in 

figure 3]

Site 1

Vegetation Area, in square 

meters Percentage

Unidentified perennial grass 8.91 6.30

Mojave indigobush (Psorothamnus arborescens) 4.24 30.00

Sandhill muhly (Muhlenbergia pungens) 2.46 1.74

Stickleaf (Mentzelia pumila) 0.91 0.64

Rabbitbrush (Ericameria nauseosus) 0.64 0.45

Snakeweed (Gutierrezia sarothrae) 0.57 0.40

Narrowleaf yucca (Yucca angustissima) 0.57 0.40

Unidentified shrub, dead 0.49 0.35

Russian thistle (Salsola sp.), dead 0.48 0.34

Indian ricegrass (Oryzopsis hymenoides) 0.37 0.26

Saltbush (Atriplex canescens) 0.14 0.10

Unidentified annual forb; pigweed (Amaranthus sp.)? trace trace

Total vegetation cover 19.8 14.0

Substrate Area, in square 

meters Percentage

Sand 139 98.0

Rock 0 0

Leaf litter 2.83 2.00

Biologic soil crust 0 0

Russian-thistle litter 0.20

Total gap length, in percent 82.8

Mean basal gap length, in centimeters 114
62 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 2

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 10.9 7.70

Sandhill muhly (Muhlenbergia pungens) 5.94 4.20

Rabbitbrush (Ericameria nauseosus) 2.83 2.00

Indian ricegrass (Oryzopsis hymenoides) 2.26 1.60

Shrub, unidentified, dead 1.63 1.15

Russian thistle (Salsola sp.), dead 1.36 0.96

Snakeweed (Gutierrezia sarothrae) 0.81 0.57

Unidentified perennial grass 0.79 0.56

Stickleaf (Mentzelia pumila) 0.62 0.44

Giant dropseed (Sporobolus giganteus) 0.11 0.08

Milkvetch (Astragalus sp.) 0.02 0.01

Unidentified annual forb 0.01 0.004

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.01 0.004

Total vegetation cover 27.3 19.3

Substrate Area, in square 

meters Percentage

Sand 139 98.0

Rock 0 0

Leaf litter 2.83 2.00

Biologic soil crust 0 0

Russian-thistle litter 2.04 1.44

Total gap length, in percent 86.3

Mean basal gap length, in centimeters 267
Appendix 1. Supplementary Information 63

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 3

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 15.7 11.1

Rabbitbrush (Ericameria nauseosus) 7.63 5.40

Stickleaf (Mentzelia pumila) 3.87 2.74

Russian thistle (Salsola sp.), dead 1.13 0.80

Unidentified perennial grass 0.99 0.70

Snakeweed (Gutierrezia sarothrae), dead 0.99 0.70

Indian ricegrass (Oryzopsis hymenoides) 0.78 0.55

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.44 0.31

Giant dropseed (Sporobolus giganteus) 0.28 0.20

Unidentified shrub, dead 0.17 0.12

Unidentified annual forb 0.12 0.08

Plains spring parsley (Cymopterus acaulis) 0.003 0.002

Total vegetation cover 32.1 22.7

Substrate Area, in square 

meters Percentage

Sand 137 96.7

Rock 2.83 2.00

Leaf litter 1.84 1.30

Biologic soil crust 0 0

Russian-thistle litter 2.01 1.42

Total gap length, in percent 68.9

Mean basal gap length, in centimeters 211
64 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 4

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 22.9 16.2

Stickleaf (Mentzelia pumila) 5.51 3.90

Rabbitbrush (Ericameria nauseosus) 3.39 2.40

Russian thistle (Salsola sp.), dead 3.14 2.22

Indian ricegrass (Oryzopsis hymenoides) 1.10 0.78

Unidentified shrub, dead 0.28 0.20

Unidentified perennial grass 0.20 0.14

Giant dropseed (Sporobolus giganteus) 0.14 0.10

Globemallow (Sphaeralcea sp.) 0.11 0.08

Plains spring parsley (Cymopterus acaulis) 0.10 0.07

Snakeweed (Gutierrezia sarothrae), dead 0.07 0.05

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.07 0.05

Unidentified annual forb 0.06 0.04

Bindweed heliotrope (Heliotropium convolvulaceum) trace trace

Total vegetation cover 37.1 26.2

Substrate Area, in square 

meters Percentage

Sand 139 98.3

Rock 0 0

Leaf litter 2.40 1.70

Biologic soil crust 0 0

Russian-thistle litter 1.84 1.30

Total gap length, in percent 83.9

Mean basal gap length, in centimeters 250
Appendix 1. Supplementary Information 65

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 5

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 8.20 5.80

Rabbitbrush (Ericameria nauseosus) 5.80 4.10

Sandhill muhly (Muhlenbergia pungens) 2.26 1.60

Stickleaf (Mentzelia pumila) 1.84 1.30

Unidentified perennial grass 1.61 1.14

Russian thistle (Salsola sp.), dead 1.13 0.80

Indian ricegrass (Oryzopsis hymenoides) 0.7 0.52

Snakeweed (Gutierrezia sarothrae) 0.57 0.40

Unidentified shrub, dead 0.28 0.20

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.15 0.10

Unidentified annual forb 0.01 0.01

Total vegetation cover 22.6 16.0

Substrate Area, in square 

meters Percentage

Sand 138 97.3

Rock 0.28 0.20

Leaf litter 3.53 2.50

Biologic soil crust 0 0

Russian-thistle litter 2.88 2.04

Total gap length, in percent 77.1

Mean basal gap length, in centimeters 222
66 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 6

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 6.64 4.70

Stickleaf (Mentzelia pumila) 2.12 1.50

Rabbitbrush (Ericameria nauseosus) 1.56 1.10

Giant dropseed (Sporobolus giganteus) 1.07 0.76

Unidentified shrub, dead 0.71 0.50

Russian thistle (Salsola sp.), dead 0.42 0.30

Indian ricegrass (Oryzopsis hymenoides) 0.33 0.23

Unidentified perennial grass 0.28 0.20

Plains spring parsley (Cymopterus acaulis) 0.17 0.12

Unidentified annual forb 0.14 0.10

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.06 0.04

Total vegetation cover 13.5 9.6

Substrate Area, in square 

meters Percentage

Sand 139 98.2

Rock 0.14 0.10

Leaf litter 2.46 1.74

Biologic soil crust 0 0

Russian-thistle litter 0.14 0.10

Total gap length, in percent 73.8

Mean basal gap length, in centimeters 333
Appendix 1. Supplementary Information 67

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 7

Vegetation Area, in square 

meters Percentage

Rabbitbrush (Ericameria nauseosus) 19.7 13.9

Mojave indigobush (Psorothamnus arborescens) 8.62 6.10

Unidentified perennial grass 2.21 1.56

Ephedra (Ephedra sp.) 1.41 1.00

Russian thistle (Salsola sp.), dead 1.27 0.90

Saltbush (Atriplex canescens) 0.79 0.56

Sandhill muhly (Muhlenbergia pungens) 0.71 0.50

Indian ricegrass (Oryzopsis hymenoides) 0.57 0.40

Giant dropseed (Sporobolus giganteus) 0.42 0.30

Snakeweed (Gutierrezia sarothrae) 0.23 0.16

Stickleaf (Mentzelia pumila) 0.20 0.14

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.12 0.08

Plains spring parsley (Cymopterus acaulis) 0.06 0.04

Total vegetation cover 36.3 25.6

Substrate Area, in square 

meters Percentage

Sand 125 88.7

Rock 10.9 7.70

Leaf litter 5.09 3.60

Biologic soil crust 0 0

Russian-thistle litter 5.09 3.60

Total gap length, in percent 73.4

Mean basal gap length, in centimeters 400
68 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 8

Vegetation Area, in square 

meters Percentage

Unidentified perennial grass 11.10 7.85

Russian thistle (Salsola sp.), dead 1.81 1.28

Unidentified forb, dead 0.06 0.04

Silverleaf nightshade (Solanum elaeagnifolium), dead 0.03 0.02

Globemallow (Sphaeralcea sp.) 0.03 0.02

Indian ricegrass (Oryzopsis hymenoides) 0.01 0.01

Total vegetation cover 13.0 9.2

Substrate Area, in square 

meters Percentage

Sand 126 89.2

Rock 7.69 5.44

Leaf litter 7.63 5.40

Biologic soil crust 0 0

Russian-thistle litter 0 0

Total gap length, in percent 93.7

Mean basal gap length, in centimeters 333
Appendix 1. Supplementary Information 69

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 9

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 10.0 7.10

Unidentified shrub, dead 2.26 1.60

Stickleaf (Mentzelia pumila) 2.08 1.47

Rabbitbrush (Ericameria nauseosus), dead 1.98 1.40

Rabbitbrush (Ericameria nauseosus), live 0.99 0.70

Unidentified perennial grass 0.14 0.10

Russian thistle (Salsola sp.), dead 0.14 0.10

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.08 0.06

Indian ricegrass (Oryzopsis hymenoides) 0.06 0.04

Unidentified perennial forb 0.03 0.02

Unidentified annual forb 0.003 0.002

Total vegetation cover 17.8 12.6

Substrate Area, in square 

meters Percentage

Sand 103 72.6

Rock 19.8 14.0

Leaf litter 4.24 3.00

Biologic soil crust 14.7 10.4

Russian-thistle litter 3.53 2.50

Total gap length, in percent 75.9

Mean basal gap length, in centimeters 1,330
70 Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 10

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 6.50 4.60

Rabbitbrush (Ericameria nauseosus) 6.08 4.30

Stickleaf (Mentzelia pumila) 2.97 2.10

Unidentified shrub, dead 0.85 0.60

Russian thistle (Salsola sp.), dead 0.42 0.30

Unidentified perennial grass 0.14 0.10

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.12 0.09

Indian ricegrass (Oryzopsis hymenoides) 0.03 0.02

Unidentified perennial forb 0.01 0.01

Total vegetation cover 17.1 12.1

Substrate Area, in square 

meters Percentage

Sand 112 79.2

Rock 26.0 18.4

Leaf litter 3.39 2.40

Biologic soil crust 0 0

Russian-thistle litter 0.14 0.10

Total gap length, in percent 77.6

Mean basal gap length, in centimeters 167
Appendix 1. Supplementary Information 71

Table 7. Vegetation cover and substrate measured in March 2012 in the study area 

near Teesto Wash, Navajo Nation, Arizona.—Continued

Site 11

Vegetation Area, in square 

meters Percentage

Mojave indigobush (Psorothamnus arborescens) 13.3 9.40

Stickleaf (Mentzelia pumila) 1.92 1.36

Rabbitbrush (Ericameria nauseosus) 1.70 1.20

Unidentified shrub, dead 1.41 1.00

Indian ricegrass (Oryzopsis hymenoides) 0.99 0.70

Giant dropseed (Sporobolus giganteus) 0.42 0.30

Russian thistle (Salsola sp.), dead 0.14 0.10

Unidentified aster (Asteraceae family), dead 0.11 0.08

Unidentified annual forb; pigweed (Amaranthus sp.)? 0.06 0.04

Unidentified perennial forb 0.03 0.02

Total vegetation cover 20.1 14.2

Substrate Area, in square 

meters Percentage

Sand 138 97.3

Rock 0 0

Leaf litter 3.53 2.50

Biologic soil crust 0.28 0.20

Russian-thistle litter 2.12 1.50

Total gap length, in percent 66.7

Mean basal gap length, in centimeters 333

Produced in the Menlo Park Publishing Service Center, California

Manuscript approved for publication, July 25, 2012

Edited by George Havach

Layout and Design by Vivian T. Nguyen
Draut, Redsteer, and Amoroso—Vegetation, Substrate, and Eolian Sediment Transport at Teesto Wash, Navajo Nation, 2009–2012—Scientific Investigations Report 2012-5095