LRDPanrep2001CU.doc

LAND RETIREMENT DEMONSTRATION PROJECT

YEAR THREE

2001 ANNUAL REPORT

September, 2002

Prepared for:

Robert May (USBR), Bea Olsen (USFWS), and Tracy Rowland (USBLM)

Interagency Land Retirement Team

1243 N Street

Fresno, CA 93721

List of Preparers:

Curtis E. Uptain1, Nur P. Ritter1, Stephen L. Lee2, Stephen A. Laymon3, Kimberly E.

Kreitinger1, Scott E. Phillips1, Adam C. Harpster1, Amy J. Kokx1, Adrian J. Howard1, Steve R.

Messer1, Darren P. Newman1, Scott W. Deal, Patrick A. Kelly1, Daniel F. Williams1

1 California State University, Stanislaus

Endangered Species Recovery Program

1900 N Gateway Blvd., Suite 101

Fresno, CA 93727

2 United States Bureau of Reclamation

Interagency Land Retirement Team

1243 N Street

Fresno, CA 93721

3 United States Bureau of Land Management

Bakersfield Field Office

3801 Pegasus Drive

Bakersfield, CA 93308
Land Retirement Demonstration Program: Year 3

i

ACKNOWLEDGEMENTS

The Land Retirement Demonstration Project has been implemented with considerable

team effort. Bob May (USBR), Tracy Rowland (USBLM), and Bea Olsen (USFWS)

have the daunting role of Administration, Land acquisition, and Agency coordination.

Without their dedication and hard work, none of this would have been possible. Stephen

Lee and Joseph Brummer (USBR) collected, analyzed, and synthesized the physical

impacts information. Siran Erysian (USBR) provided GIS support and maps for the

physical impacts section and Scott Phillips and Laurie Williams (ESRP) provided GIS

support for the remainder of the effort. Stephen Laymon and Larry Saslaw (USBLM)

conducted the planning, restoration, and management of the Atwell Island site. Stephen

Lee, Bea Olsen, and Tracy Rowland provided valuable input on various drafts of this

manuscript.

ESRP field staff who also contributed an immense amount of effort to this project

include: Howard Clark, Ellen Cypher, Richard Gebhart, Patrick Morrison, and Foung

Vang. They, along with many of the authors have spent many grueling late nights, cold

early mornings, and hot afternoons in the field. They have spent much time and effort

organizing equipment and entering data. Karen Dulik, formerly of ESRP and now with

the California Department of Water Resources, contributed a substantial amount of time

carrying on with her duties as restoration botanist for the Land Retirement Demonstration

Project, even after she took on her new position. Finally, we are grateful to Dr. Stuart

Hurlbert (San Diego State University) for his help in study design considerations and

statistical problem solving.

The Ryan Farming Company coordinated the barley irrigation and harvest in 2001. We

would also like to thank Mr. Robert Jones, our neighboring farmer, for his help in

maintenance on the site, coordination of the barley planting in fall 2001, and for

assistance in installing a variety of experimental trials at the Tranquillity site. Mr. Jack

Mitchell, Mr. Monte Mitchell, and Mr. Ron Nickell provided equipment and personnel

for the work on our study blocks at Atwell Island. They assisted in planting barley,

harvesting barley, creating microtopographic contours, and imprinting native seed on the

treatment plots. They have also assisted the U.S. Bureau of Land Management in the

installation of a variety of restoration trials.

Richard Lopez at Westlands Water District has been a tremendous help in guiding us

through the convoluted web of water allocations, orders, and transfers. Without his help

we may well have needlessly spent a great deal of money on unused water. We would

like to thank Southern California Edison, Westside Transplants, and Intermountain

Nursery for providing us with native seedlings and S & S Seeds and Pacific Coast Seeds

for providing us with native seed mixes. Finally we would like to thank the California

Department of Fish and Game, Fresno West Golf and Country Club, Westlands Water

District, and Paul Lanfranco for allowing us to collect native seed from various locations

in Fresno County. Additionally we would like to thank the Center for Natural Lands

Management for permission to collect seed at the Thomas Payne Preserve for the Atwell

Island site.
Land Retirement Demonstration Program: Year 3

ii

EXECUTIVE SUMMARY

Introduction

Vast tracts of land on the west side of the San Joaquin Valley are characterized by a high

groundwater level and high selenium content. The application of irrigation water to these

lands results in an accumulation of poor-quality drain-water. The elimination of drain

water is a chronic problem on these lands. One way to reduce the accumulation of drain

water and to lessen problems associated with its disposal is to retire the land from

agricultural production. The Central Valley Project Improvement Act (CVPIA) of 19921

authorized a land retirement program as recommended in the San Joaquin Valley

Drainage Program Final Report2. An interagency team consisting of representatives from

the United States Bureau of Reclamation (USBR), the United States Fish and Wildlife

Service (USFWS), and the United States Bureau of Land Management (USBLM) has

been assembled to accomplish the goals of the CVPIA Land Retirement Program3. This

program may purchase land, water, and other property interests from willing sellers who

receive Central Valley Project water allocations. Although land retirement may provide

solutions to some problems associated with agricultural drainwater, land retirement

comes with its own set of challenges including: land acquisition, redistribution of the

acquired water, and habitat restoration to reduce the potential for agricultural weeds and

pests that would adversely impact neighboring farming interests.

Prior to initiating land retirement on a greater scale, a 15,000-acre demonstration project

has been designed to test various methods of habitat restoration. The objectives are to

assess the effects of land retirement on drain water and groundwater levels, evaluate its

potential to decrease bio-available selenium and other toxic compounds, and to determine

relative costs and success of different restoration treatments in re-establishing native

biota on the sites. Two study sites, one in western Fresno County (Tranquillity site) and

the other in Tulare and Kings counties (Atwell Island site), have been established. The

California State University Stanislaus, Endangered Species Recovery Program (ESRP) is

leading the biological studies at both sites, conducting restoration efforts, and managing

the Tranquillity site. The physical impacts of land restoration are being examined by the

USBR at both sites. The USBLM is conducting restoration efforts and managing the

Atwell Island site.

This annual report summarizes information collected in 2001 from both the Tranquillity

and Atwell Island study sites, and also results through 2001 of the Habitat Restoration

Studies, site-wide biological surveys, restoration trials and efforts at both sites, and

impacts of land retirement on physical properties (groundwater, soils, geology, etc). Data

 

1 Federal Register: March 9, 1998. Vol. 63, No. 45. p11453.

2

 San Joaquin Valley Drainage Program. 1990. Fish and wildlife resources and agricultural drainage in the San Joaquin Valley,

California. Vols I and II. 707pp+appendices.

3 U.S. Department of Interior. 1997. Central Valley Project Improvement Act Section 3408(h): Land Retirement Program

Guidelines. Unpubl. report, Interagency Land Retirement Team, Fresno, CA, 19 pp.
Land Retirement Demonstration Program: Year 3

iii

collected for the Habitat Restoration Studies include plant cover and survivorship,

invertebrate richness and abundance, amphibian and reptile richness and abundance,

avian richness and abundance, and small mammal richness and abundance. Site-wide

data collection includes night spotlighting surveys, track station surveys, winter raptor

surveys, contaminants monitoring, and plant cover and survivorship on various test plots.

Physical impact data that are being collected include soil type and soil chemistry,

groundwater levels, and groundwater contaminants.

Tranquillity Habitat Restoration Study

Although imprinting of native seeds in 1999 was successful in establishing native plants

on our study plots in 2000, by 2001 frequency, cover, and abundance of native plants had

diminished and exotic and native weedy species predominated. While conditions in the

southern San Joaquin Valley region in 2000 and 2001 have not been favorable for

production of desirable native plants, it is becoming clear that improved weed control is

necessary for restoration of retired agricultural lands.

Invertebrate richness did not vary by treatment in any year, nor did richness vary among

any given year across treatments. Abundance of invertebrates did not vary by treatment,

except in 2001 where the contoured but non-restored plots had the fewest invertebrates.

For most treatments, there was a trend of increasing invertebrate abundance from 1999 to

2000, then decreasing abundance in 2001. The most notable differences in richness were

that block 1 had greater richness than any other block during all years and that block 3

had a relative low richness in 2000. Abundance among the blocks were most similar in

1999 and most variable in 2001, indicating that blocking effect is increasing. Invertebrate

composition exhibited temporal changes. Thysanoptera dominated the invertebrate

population in 1999 whereas Hemiptera and, secondarily, Thysanoptera dominated in

2000. In 2001 Orthoptera was dominant.

No amphibians or reptiles were captured on the plots, indicating that they remain scarce.

Incidental sightings on the plots included a California king snake and a western fence

lizard. Also, numerous western toads and a California king snake were observed in the

vicinity of the study plots during site-wide survey efforts.

Richness and abundance of birds were highly variable among seasons in 2001. We

expected this because of the numerous seasonal migrants that visit the study site. There

were no observable differences in richness or abundance between treatments. Spring

abundance increased each year from 1999 to 2001 and winter abundance increased from

2000 to 2001. Most species using the plots were grassland obligates or facultative

grassland species. With the exception of horned larks, avian species of special concern

were more abundant on the plots than in previous years. Two very desirable species,

northern harriers and short-eared owls, were observed nesting on the plots.

Deer mice were the most abundant small mammal captured, although house mice, ornate

shrews, California voles, and a single harvest mouse also were captured. The abundance

of small mammals, particularly deer mice, has increased each year since 1999. The

abundance of deer mice tended to be greater on plots that had a combination of

restoration and contouring. Although treatment type appeared to have no effect on house
Land Retirement Demonstration Program: Year 3

iv

mouse abundance, shrews were most abundant on restored plots and voles were most

abundant on contoured plots.

Atwell Island Habitat Restoration Study

In 2001, baseline data were collected on the Atwell Island study plots while they were

still covered with a barely crop. The barley crop was harvested in the fall and treatments

were applied. The Atwell Island HRS site seemed to possess few floristic similarities to

the Tranquillity HRS site during its baseline year. In particular, a number of aggressively

weedy species that were abundant at the Tranquillity HRS site were much less abundant

at the Atwell Island HRS site. The absence of these species suggests that the Atwell

Island site may not be plagued by weeds to the same degree as the Tranquillity site.

Nevertheless, the noxious weed fivehook bassia was fairly abundant in the Atwell Island

HRS plots, which may prove to be a significant problem in future years.

Invertebrate richness among the three study blocks was relatively constant, however,

species composition varied. Block 1 was dominated by 4 orders (Acari, Thysanoptera,

Isopoda, and Araneae), Block 2 was dominated by 2 orders (Acari and Thysanoptera) and

Block 3 was dominated by a single order (Coleoptera). Sweep samples were collected,

but are not yet completely identified and analyzed.

Neither amphibians nor reptiles were observed on the study plots. Incidental sightings at

the HRS site included western toads, gopher snakes, and horned lizards.

Blocks 1 (10 species) and 2 (11 species) had relatively high avian richness as compared

to Block 3 (5 species). Red-winged blackbirds, horned larks, western meadowlarks, and

savannah sparrows were the most common birds observed.

No small mammals were captured on the study plots. Nevertheless, one San Joaquin

pocket mouse (a federal Species of Special Concern) was captured by hand near one of

the plots on Block 3.

Restoration Studies at Tranquillity

Results from a trial of two seeding methods (imprinting and drilling) of native seeds,

while not statistically significant, suggested that the response of individual species to

these methods is highly variable. These results suggest the need for more rigorous trials

to determine the most appropriate method for seeding various species.

An investigation of seeding barley by imprinting and drilling suggested that either

approach is acceptable. Likewise, a trial of these two seeding methods using a seed mix

of barley and native grasses yielded no statistically significant differences. Nevertheless,

a greater number of introduced weedy species was noted on plots seeded with the mixture

containing native grasses than on the plots seeded solely with barley. This suggests that

some of the weedy species on the HRS plots may have been introduced through the

inclusion of their seeds in commercially purchased native seed mixes.
Land Retirement Demonstration Program: Year 3

v

Biological Monitoring at Tranquillity

As in 1999 and 2000, there was seasonal variability in species richness during

spotlighting surveys in 2001. There was a trend of increasing richness from 1999 to

2001. No single species was observed during every season; however, barn owls, blacktailed hares, desert cottontails, and short-eared owls were present most seasons.

Generally, barn owls, black-tailed hares, desert cottontails, and red-tailed hawks were the

most abundant species.

Species richness was highest on the track stations in the summer of 2000 and spring 2001

and the lowest in fall and winter 1999. Abundance of tracks was greatest in summer of

2001 and lowest in fall and winter of 1999. The greatest frequency of visitation and the

greatest rate of visitation were of small mammals, except in the summer and winter of

2000. The high variability observed in the richness, abundance, frequency and rate of

tracks may be indicative of the high variability in climactic conditions of the San Joaquin

Valley, rather than being indicative of responses to restoration efforts at the site.

American kestrels and northern harriers were the most common raptors seen during the

raptor surveys, but red-tailed hawks, loggerhead shrikes, and white-tailed kites were also

frequently observed. Northern harriers and red-tailed hawks increased in rate of

occurrence each year. A peregrine falcon and a ferruginous hawk, both species of special

concern, were first observed on the site in 2001. Individuals of both species were

observed foraging over the study plots.

Bio-accumulation of selenium does not appear to be a concern at the Tranquillity site.

Selenium levels of all biota sampled (vegetation, invertebrates, and small mammals) did

not increase from 1999 to 2001. In fact, there is a trend of decreasing selenium levels in

most groups sampled. Selenium levels of most biotic groups fall within typical

background levels. These levels are 0.01 to 0.6 mg/kg for terrestrial vegetation, 0,1 to

2.5 mg/kg for terrestrial invertebrates, <1.0 to 4.0 mg/kg for whole bodies of small

mammals, and 1.0 to 10.0 mg/kg for small mammal livers. The only plant that exceeded

the vegetation background levels was Brassica nigra, a known selenium accumulator.

The levels of selenium observed in B. nigra (about 1.0 mg/kg) collected from the

Tranquillity site are very low considering the levels that selenium that can be

accumulated (500 to 1,000 mg/kg). Selenium levels in spiders and isopods slightly

exceeded typical background levels for terrestrial invertebrates. However, spiders are

predators and isopods are detritivores, so selenium bio-accumulation in these taxa are

expected to be higher than in beetles, crickets, and other typical terrestrial invertebrates.

The levels of selenium accumulation in bodies and livers of both deer mice and shrews

are at the low end of the range typical for selenium accumulation in small mammals.

Restoration Studies at Atwell Island

During the fall of 2001 the Bureau of Land Management established a series of 456 small

plots (1/1000 acre) to test the effectiveness of differing soil preparations and seeding

rates on germination success and survival of native shrubs, forbs, and grasses. Seed from

29 species were planted at rates of 40, 80, and 160 pounds per acre. Four methods of site

preparation were used: scraping the surface, disking to 8 inches, harrowing to 4 inches,
Land Retirement Demonstration Program: Year 3

vi

and no preparation. Supplemental nitrogen and phosphorus were added to some plots.

Results of these trials will be available after the growing season in spring 2002.

Approximately 1.5 miles of hedgerows were planted with a seed mix (of Atriplex

lentiformis, Leymus triticoides, Vulpia microstachys, Amsinkia menziesii, Helianthus

annus, Frankenia salina, Eremocarpus setigerus), Dichelostemma capitatum, and

Hemizonia pungens) using a range drill. A seed mix (of Eremocarpus setigerus,

Sporobolus airoides., Frankenia salina, Hemizonia pungens, Lasthenia sp., Atriplex

polycarpa, A. spinifera, Vulpia sp., Gilia sp., Suaeda moquinii, Isocoma acradenia) was

also planted on approximately 240 acres using both a range drill and an imprinter. Three

small areas (approximately 30 ft. x 90 ft.) that were seeded were burned immediately

prior to planting.

Approximately 150 native trees and shrubs (that were rooted in supercells—10 in deep

plastic containers) were planted along the Alpaugh canal and drip irrigation was installed.

Drip irrigation also was installed in an 80-acre area that was planted with the range drill

to supply supplemental water to shrubs during their first growing season.

A restoration effort also was conducted at an abandoned evaporation pond. Several

species of salt-tolerant plants were planted as seedlings or seeds.

Biological Monitoring at Atwell Island

The most commonly observed species during spotlighting surveys, in order of decreasing

abundance, were: barn owls, kangaroo rats, western toads, desert cottontails, blackcrowned night herons, and great egrets. Species richness was higher in September than in

December.

The greatest abundance and variety of tracks were observed during the September track

station survey. In September, the most abundant tracks were of mice, insects, kangaroo

rats, and western toads, whereas in December the most abundant tracks were of mice,

birds, and dogs. The frequency and rate of visitation of invertebrates, amphibians, and

reptiles, birds, and small mammals were greatest in the fall.

Eight species of raptors and loggerhead shrikes were observed during the winter raptor

survey. The most commonly seen raptors were red-tailed hawks and northern harriers.

Prairie falcons and ferruginous hawks also were intermittently observed. A total of 71

species of birds were observed during a mid-winter bird count. The most commonly

observed birds were red-winged blackbirds, house finch, white-crowned sparrows,

savannah sparrows, horned larks, and European starlings. Additionally, incidental

sightings of 102 species of birds, 5 species of mammals, 2 species of reptiles, and 5

species of butterflies were recorded.

Bio-accumulation of selenium does not appear to be a concern at the Atwell Island site.

Selenium levels of all taxa (vegetation, invertebrates, and small mammal) sampled were

within typical background levels. These levels are 0.01 to 0.6 mg/kg for terrestrial

vegetation, 0,1 to 2.5 mg/kg for terrestrial invertebrates, <1.0 to 4.0 mg/kg for whole

bodies of small mammals, and 1.0 to 10.0 mg/kg for small mammal livers. Selenium
Land Retirement Demonstration Program: Year 3

vii

levels of all taxa did not increase from 2000 to 2001. In fact, there is a slight trend of

decreasing selenium levels.

Physical Impacts at Tranquillity

The Tranquillity Land Retirement Demonstration Project site is underlain by flood basin

deposits consisting of moderately to densely compacted clays that range in thickness

from 5 to 35 ft. The flood basin clays have low permeability and provide poor drainage

conditions for irrigated agricultural production. The U.S. Department of Agriculture soil

types found at the site in order of abundance include the Tranquillity clay (80%), the

Lillis clay (10%) and the Lethent silt loam (10%). Data on baseline soil chemistry,

collected during 1999, indicate that the site soils are highly to moderately saline, and

contain elevated concentrations of selenium and boron when compared to other soils in

the San Joaquin Valley. The baseline data on soil chemistry collected during 1999 are

adequate for establishing project baseline soil concentrations of selenium, boron, and

salinity.

Groundwater monitoring data collected to date support the conceptual model of a

declining, shallow water table in response to land retirement. The average decline in

water level observed in 10 monitoring wells for the period between August 1999 and

October 2001 was 4 feet. The area of the site underlain by a shallow water table within 7

feet of the land surface decreased from 600 acres (30% of the site) to 34 acres (less than

2% of the site) during the time period from October 1999 to October 2001. Large

vertical groundwater gradients measured at the site indicate perched water-table

conditions in the shallow groundwater system.

Baseline groundwater quality data taken during 1999 indicate that the shallow

groundwater is a highly saline, sodium sulfate type of water that contains high

concentrations of selenium and boron (median electrical conductivity = 43,260 microsiemens/cm, median selenium concentration = 1280 μg/l, median boron concentration =

46 mg/liter). Stable isotope data indicate that the shallow groundwater has undergone

evaporation resulting in high salinity and trace element concentrations. Selenium

concentrations observed in deep wells completed in the underlying Sierra Nevada

deposits at the site are below the analytical detection limit for this study (less than 0.4

μg/l). Reducing geochemical conditions in the Sierran deposits underlying the northern

portion of the site may account for this observation. Tritium data from the shallow

monitoring wells indicate that the shallow groundwater consists of a mixture of water

recharged before and after 1952. Tritium data from the deep wells completed in the

Coastal Range deposits at the site indicate that the groundwater was recharged before

1952. Data on groundwater quality collected during 1999 are adequate for establishing

baseline project conditions. No surface water ponding was observed at the site during

2001.

Physical Impacts at Atwell Island

The Atwell Island demonstration site lies on the southwestern margin of the Tulare Lake

bed. The site is underlain by lakebed and marsh deposits consisting primarily of clay and

silt with some sand. Soils in the Atwell Island study area consist of silt and sand loams
Land Retirement Demonstration Program: Year 3

viii

that are formed from alluvium derived from igneous and sedimentary rocks. The U.S.

Department of Agriculture soil mapping units found at the site in order of abundance

include the Posochanet silt loam, Nahrumb silt loam, Westcamp silt loam, Excelsior fine

sandy loam, and Lethent fine sandy loam. Baseline data on soil chemistry will be

collected at the site during 2002 to establish project baseline soil concentrations of

selenium, boron, and salinity within the study research blocks. Monitoring wells were

installed at the site in the fall of 2001 to establish baseline groundwater conditions.

Initial groundwater level measurements indicate the presence of a perched water table

beneath much of the site. The year 2002 will be the baseline for groundwater levels and

groundwater quality. Surface water monitoring will also commence in 2002.

Tours, Presentations, Conferences, and Workshops

One site tour of the Tranquillity site was given in 2001. Information obtained during our

studies was presented at conferences sponsored by the western section of The Wildlife

Society and The Society for Ecological Restoration, California Chapter. Additionally,

presentations were given to The Westlands Resource Conservation District and to

students at California State University Stanislaus. Land Retirement Team members

attended a workshop on restoration sponsored by the USBLM, a workshop on field

ornithological techniques sponsored by Point Reyes Bird Observatory, and attended a

national conference sponsored by The Wildlife Society.
Land Retirement Demonstration Program: Year 3

ix

TABLE OF CONTENTS

ACKNOWLEDGEMENTS ...............................................................................................................i

EXECUTIVE SUMMARY ...............................................................................................................ii

I. INTRODUCTION......................................................................................................................... 1

A. Background .............................................................................................................................................1

B. Development of the Land Retirement Demonstration Project.................................................................3

C. Demonstration Project Site Locations and Descriptions .........................................................................4

1. Tranquillity Site ..................................................................................................................................4

2. Atwell Island Site................................................................................................................................5

D. Project scope............................................................................................................................................7

II. HABITAT RESTORATION STUDY........................................................................................ 8

A. Tranquillity..............................................................................................................................................8

1. Study Design .......................................................................................................................................8

2. Biological Monitoring.........................................................................................................................9

B. Atwell Island..........................................................................................................................................36

1. Study Design .....................................................................................................................................36

2. Biological Monitoring.......................................................................................................................37

III. SITE-WIDE ACTIVITIES...................................................................................................... 50

A. Tranquillity............................................................................................................................................50

1. Restoration Studies............................................................................................................................50

2. Biological Monitoring.......................................................................................................................73

3. Management......................................................................................................................................87

B. Atwell Island..........................................................................................................................................89

1. Restoration Studies............................................................................................................................89

2. Biological Monitoring.......................................................................................................................93

3. Management....................................................................................................................................100

IV. PHYSICAL IMPACTS.......................................................................................................... 102

A. Tranquillity Site...................................................................................................................................102

1. Tranquillity Site Geology................................................................................................................102

2. Tranquillity Site Soils .....................................................................................................................102

3. Weather: Tranquillity Site...............................................................................................................104

4. Irrigation: Tranquillity Site .............................................................................................................106

5. Hydrology and Surface Water Monitoring: Tranquillity Site .........................................................107

6. Groundwater Level Monitoring: Tranquillity Site ..........................................................................107

7. Groundwater Response to Land Retirement: Tranquillity Site ......................................................109

8. Groundwater Quality Monitoring: Tranquillity Site .......................................................................116

B. Atwell Island Site ................................................................................................................................126

1. Atwell Island Site Geology .............................................................................................................126

2. Atwell Island Site Soils...................................................................................................................126

3. Weather: Atwell Island Site ............................................................................................................128

4. Irrigation: Atwell Island Site...........................................................................................................128

5. Hydrology and Surface Water Monitoring: Atwell Island Site.......................................................129

6. Groundwater Level Monitoring: Atwell Island Site........................................................................129

7. Groundwater Levels: Atwell Island Site .........................................................................................130

8. Groundwater Quality Monitoring: Atwell Island Site.....................................................................131
Land Retirement Demonstration Program: Year 3

x

TABLE OF CONTENTS (cont.)

V. TOURS, PRESENTATIONS, CONFERENCES, AND WORKSHOPS............................ 132

VI. REFERENCES ....................................................................................................................... 133

VII. APPENDICES....................................................................................................................... 139

A. Additional Vegetation Tables..............................................................................................................139

B. Rank-abundance Graphs Generated from Vegetation Sampling on the Tranquillity Habitat

Restoration Study Plots, 1999-2001..........................................................................................................145

C. Avian Species Observed on the Tranquillity Habitat Restoration Study Plots, 1999-2001 ................150
Land Retirement Demonstration Program: Year 3

xi

TABLE OF TABLES

Table 1. Seeded species and additional native species observed on the study plots at the

Tranquillity HRS site. ................................................................................................................ 11

Table 2. Frequency of species noted in the imprinted plots during vegetation sampling, 2001...... 12

Table 3. Overview of species grouped by origin at Tranquillity HRS............................................. 13

Table 4. Known "pest plants" observed in the Tranquillity HRS plots............................................ 17

Table 5. Composition of invertebrates collected in pitfall traps at the Tranquillity site, 1999 to

2001............................................................................................................................................ 22

Table 6. Avian relative abundance and ranked species composition on the Tranquillity site study

plots, 1999 to 2001..................................................................................................................... 28

Table 7. Shrews and voles captured in pitfall traps on the Tranquillity site study plots, 1999 to

2001............................................................................................................................................ 34

Table 8. The ten most abundant species at the two HRS sites during baseline sampling. Species

are presented in descending abundance for each site................................................................. 42

Table 9. Known "pest plants" observed in the Atwell Island HRS Plots......................................... 43

Table 20. Composition of invertebrates collected in pitfall traps in the 3 study blocks at the

Atwell Island site, 2001. ............................................................................................................ 46

Table 21. Bird species observed and abundance on the 3 study blocks at the Atwell Island site,

2001............................................................................................................................................ 48

Table 22. Overview of species encountered in imprinting vs. drilling of native seed..................... 53

Table 23. Summary of species encountered in imprinting vs. drilling of native seed trial.............. 55

Table 24. Overview of species encountered in imprinting vs. drilling of cover crops. ................... 57

Table 25. Summary of species classes encountered in imprinting vs. drilling of cover crops. ....... 58

Table 26. Overview of species encountered during vegetation sampling of the 160-acre

restoration area for 2001 (Section 23, Tranquillity site)............................................................ 60

Table 27. Summary of species classes encountered during vegetation sampling of the Section 23

restoration. ................................................................................................................................. 61

Table 28. Seed mix and application rate for the hedgerow seeding at the Tranquillity site. ........... 63

Table 29. Species seeded in the marsh area at the Tranquillity site, 2002....................................... 64

Table 30. Seed mix and application rate for ditch bank seeding at the Tranquillity site. ................ 65

Table 31. Dates, species collected, and locations of 2001 native seed collections.......................... 66

Table 32. Native plants seed available for planting in the native seed nursery at the Tranquillity

site.............................................................................................................................................. 68

Table 33. Rates of species occurrence during 1999 to 2001 spotlighting surveys at the

Tranquillity site.......................................................................................................................... 75

Table 34. Frequency and rate of visitation of wildlife at track stations at the Tranquillity site,

1999 through 2001. .................................................................................................................... 77

Table 35. Frequency and rate of occurrence of bird species observed at the Tranquillity site,

1999 - 2001. ............................................................................................................................... 78

Table 36. Selenium concentrations in plant species collected from the Tranquillity site................ 82

Table 37. Selenium concentrations in plant species grouped as selenium accumulators and

selenium non-accumulators at the Tranquillity site................................................................... 84
Land Retirement Demonstration Program: Year 3

xii

TABLE OF TABLES (cont.)

Table 38. Selenium concentrations in invertebrate species collected from the Tranquillity site..... 86

Table 39. Selenium concentrations in mammal species collected from the Tranquillity site.......... 86

Table 40. Frequency and rate of animals observed during spotlighting surveys at the Atwell

Island site, 2001. ........................................................................................................................ 94

Table 41. Results of track station surveys at the Atwell Island site, 2001....................................... 95

Table 42. Number of observations, frequency, and rate of wintering raptors at the Atwell Island

site, 2001.................................................................................................................................... 96

Table 43. Selenium levels in samples of vegetation collected from the Atwell Island site during

baseline surveys in 2000 and 2001. ........................................................................................... 99

Table 44. Selenium levels in samples of invertebrates collected from the Atwell Island site

during baseline surveys in 2000 and 2001............................................................................... 100

Table 45. Selenium levels in samples of small mammals collected from the Atwell Island site

during baseline surveys in 2000 and 2001............................................................................... 100

Table 46. Monthly CIMIS weather data and estimated barley crop water use at the Tranquillity

site for calendar Year 2001...................................................................................................... 105

Table 47. Estimated barley crop consumptive water use as compared with precipitation and

applied irrigation water at the Tranquillity site........................................................................ 107

Table 48. Groundwater level decline observed in ten wells at the Tranquillity site for the time

period from August, 1999 to October, 2001............................................................................ 116

Table 49. Groundwater quality data for shallow wells at the Tranquillity site - major ions and

field parameters........................................................................................................................ 118

Table 50. Groundwater quality data for deep wells at the Tranquillity site - major ions and field

parameters................................................................................................................................ 118

Table 51. Groundwater quality data for shallow wells at the Tranquillity site - trace elements

and tritium................................................................................................................................ 120

Table 52. Groundwater quality data for deep wells at the Tranquillity site - trace elements and

tritium....................................................................................................................................... 120

Table 53. Preliminary analysis of Selenium trends in groundwater at the Tranquillity site.......... 123

Table 54. Estimated 2001 net crop water requirement and deep percolation losses at the Atwell

Island site. ................................................................................................................................ 129

Table A1. Overview of species encountered during all vegetation sampling at the Tranquillity

HRS site. .................................................................................................................................. 139

Table A2. Overview of species encountered in Tranquillity HRS vegetation sampling, 2001. .... 141

Table A3. Frequency of species noted during vegetation sampling, 2001. ................................... 142

Table A4. Overview of species encountered during the pre-project inventory of the Atwell

Island site and baseline vegetation sampling of the Atwell Island HRS plots......................... 143

Table C1. Avian species observed on the Tranquillity HRS plots, 1999-2001. ............................ 150
Land Retirement Demonstration Program: Year 3

xiii

 LIST OF FIGURES

Figure 1. Drainage impacted lands in the San Joaquin Valley. ........................................................... 2

Figure 2. Current configuration of the Tranquillity site....................................................................... 5

Figure 3. Current configuration of the Atwell Island site.................................................................... 6

Figure 4. Map of the Tranquillity site showing the randomized block design and treatments

applied to each study plot. ............................................................................................................. 9

Figure 5. Ordinations by Detrended Correspondence Analysis (DCA) of the Tranquillity HRS

plot vegetation................................................................................................................................ 15

Figure 6. Invertebrate richness (generated from pitfall data) by treatment at the Tranquillity site..... 20

Figure 7. Invertebrate abundance (generated from pitfall data) by treatment at the Tranquillity

site.................................................................................................................................................. 20

Figure 8. Invertebrate richness by block at the Tranquillity site. ........................................................ 21

Figure 9. Invertebrate abundance by block at the Tranquillity site. .................................................... 22

Figure 10. Locations of pitfall arrays, sweep transects, cover boards, avian transects, and small

mammal trapping lines on Tranquillity HRS plot.......................................................................... 24

Figure 11. Avian richness by season at the Tranquillity site. .............................................................. 26

Figure 12. Avian abundance by season at the Tranquillity site. .......................................................... 26

Figure 13. Seasonal relative abundance of selected avian species at the Tranquillity site.................. 30

Figure 14. Abundance of small mammals by season at the Tranquillity site. ..................................... 31

Figure 15. Abundance of small mammals by treatment at the Tranquillity site.................................. 32

Figure 16. Abundance of small mammals by block at the Tranquillity site. ....................................... 33

Figure 17. Map of the Atwell Island site showing the randomized block design................................ 36

Figure 18. Map of an experimental block at the Atwell Island site showing the placement of

treatments plots. ............................................................................................................................. 37

Figure 19. Locations of research areas at the Atwell Island site.......................................................... 38

Figure 20. Differences in abundances between introduced and native species on the Atwell

Island HRS plots. ........................................................................................................................... 40

Figure 21. Rank-abundance of baseline plant species data from the Tranquillity (1999) and

Atwell Island (2001) Habitat Restoration Studies, showing the 20 species with the greatest

average abundance for each site. ................................................................................................... 41

Figure 22. Locations of pitfall arrays, sweep transects, cover boards, avian transects, and small

mammal trapping lines on an Atwell Island HRS plot. ................................................................. 45

Figure 23. Locations of the various restoration study areas at the Tranquillity site............................ 50

Figure 24. Location of the Imprinting vs. drilling of native seed trial, and the Imprinting vs.

drilling of cover crops trial. ........................................................................................................... 52

Figure 25. Rank-abundance of species encountered in the imprinted plots and drilled plots.............. 54

Figure 26. Rank abundance of species encountered in imprinting and drilling of cover crops:.......... 58

Figure 27. Rank-abundance of species encountered during vegetation sampling of the Section

23 restoration. ................................................................................................................................ 61

Figure 28. Locations of native plant seed collection sites near the Tranquillity site........................... 67
Land Retirement Demonstration Program: Year 3

xiv

LIST OF FIGURES (cont.)

Figure 29. Sampling locations for site-wide biological monitoring at the Tranquillity site................ 74

Figure 30. Seasonal richness of tracks observed on the track stations at the Tranquillity site,

1999 through 2001. ........................................................................................................................ 76

Figure 31. Seasonal abundance of tracks observed on the track stations at the Tranquillity site,

1999 through 2001. ........................................................................................................................ 77

Figure 32. Sampling locations for contaminant monitoring at the Tranquillity site............................ 80

Figure 33. Selenium concentrations in invertebrates sampled from the Tranquillity site. .................. 85

Figure 34. Locations of restoration studies conducted at the Atwell Island site. ................................ 89

Figure 35. Sampling locations for site-wide biological monitoring at the Atwell Island site. ............ 93

Figure 36. Locations of selenium sampling at the Atwell Island site.................................................. 98

Figure 37. U.S. Department of Agriculture soil mapping units, Tranquillity site. .............................. 104

Figure 38. Monthly precipitation and estimated barley crop consumptive water use for calendar

year 2001 at the Tranquillity site. .................................................................................................. 106

Figure 39. Monitor well and sump location map, Tranquillity site. .................................................... 109

Figure 40. Hydrographs for three agricultural drain sumps at the Tranquillity site showing a

declining shallow groundwater trend............................................................................................. 110

Figure 41. Hydrographs for monitor wells 325 and 326 at the Tranquillity site showing a

declining shallow groundwater trend............................................................................................. 111

Figure 42. Hydrographs for monitor wells 15M1 and 16A1 at the Tranquillity site showing a

declining shallow groundwater trend............................................................................................. 111

Figure 43. Depth to shallow groundwater, October, 1999................................................................... 113

Figure 44. Depth to shallow groundwater, October, 2000................................................................... 114

Figure 45. Depth to shallow groundwater, October, 2001................................................................... 115

Figure 46. Comparison of dominant major ion concentrations and electrical conductivity for

groundwater samples from shallow and deep wells. ..................................................................... 119

Figure 47. Ratio of Selenium to Manganese (Se/Mn) concentration in groundwater samples

plotted verses well depth................................................................................................................ 122

Figure 48. Plot of stable isotope data for groundwater samples from the Tranquillity site

indicating the shallow groundwater has undergone significant evaporation................................. 125

Figure 49. U.S. Department of Agriculture soil mapping units and soil sample locations at the

Atwell Island site. .......................................................................................................................... 127

Figure 50. Monitor well locations at the Atwell Island site................................................................. 130

Figure B1. Rank-abundance curves for the Block 1 study plots, Tranquillity HRS............................ 145

Figure B2. Rank-abundance curves for the Block 2 study plots, Tranquillity HRS............................ 146

Figure B3. Rank-abundance curves for the Block 3 study plots, Tranquillity HRS............................ 147

Figure B4. Rank-abundance curves for the Block 4 study plots, Tranquillity HRS............................ 148

Figure B5. Rank-abundance curves for the Block 5 study plots, Tranquillity HRS............................ 149
Land Retirement Demonstration Program: Year 3

1

I. INTRODUCTION

A. Background

Vast tracts of land on the west side of the San Joaquin Valley are characterized by a high

groundwater level and high selenium content. The application of irrigation water to these

lands results in an accumulation of poor-quality drain-water. The elimination of drain

water is a chronic problem on these lands. One way to reduce the accumulation of drain

water and to lessen problems associated with its disposal is to retire the land from

agricultural production. The Central Valley Project Improvement Act (CVPIA) of 19924

authorized a land retirement program as recommended in the San Joaquin Valley

Drainage Program Final Report5. An interagency team consisting of representatives from

the United States Bureau of Reclamation (USBR), the United States Fish and Wildlife

Service (USFWS), and the United States Bureau of Land Management (USBLM) has

been assembled to accomplish the goals of the CVPIA Land Retirement Program6.

Although land retirement may provide solutions to some problems associated with

agricultural drainwater, land retirement comes with its own set of challenges. Some of

these include: land acquisition, redistribution of the acquired water, and habitat

restoration to reduce the potential for agricultural weeds and pests that would adversely

impact neighboring farming interests.

The Land Retirement Team (LRT) is entrusted with the task of implementing the CVPIA

Land Retirement Program. Through this program, the United States Department of

Interior (USDOI) may purchase land, water, and other property interests from willing

sellers who receive Central Valley Project (CVP) water allocations and are located in

areas where there are significant drainage problems (Figure 1). Condemnation of land is

not a part of this program. However, willing sellers are numerous because of the low

productivity and high cost of agricultural production on drainage impaired lands.

The broad goals of the Land Retirement Program are to:

• Reduce the volume of drain water by retiring lands from irrigated agricultural

production on the west side of the Valley,

• Acquire water for CVPIA purposes, and

• Enhance fish and wildlife resources.

 

4

 Federal Register: March 9, 1998. Vol. 63, No. 45. p11453.

5

 San Joaquin Valley Drainage Program. 1990. Fish and wildlife resources and agricultural drainage in the

San Joaquin Valley, California. Vols I and II. 707pp+appendices.

6 U.S. Department of Interior. 1997. Central Valley Project Improvement Act Section 3408(h): Land

Retirement Program Guidelines. Unpubl. report, Interagency Land Retirement Team, Fresno, CA, 19 pp.
Land Retirement Demonstration Program: Year 3

2

Additional background information on the CVPIA Land Retirement Program can be

found in a variety of reports (USDI 1997, USDI 1999, Selmon et al. 2000, Uptain et al.

2001) and web sites (see http://www.mp.usbr.gov/cvpia/).

Figure 1. Drainage impacted lands in the San Joaquin Valley.
Land Retirement Demonstration Program: Year 3

3

B. Development of the Land Retirement Demonstration

Project

During the comment period for the Land Retirement Program Draft Environmental

Assessment (EA), concerns were raised about the magnitude of the project and the lack

of knowledge about the potential positive and negative effects of retirement of

agricultural land on a large scale (USDI 1999). The Land Retirement Demonstration

Project (LRDP) was initiated to address concerns about the scope and degree of impacts

of retirement on wildlife, drainage volume reduction, socio-economics, and overall

cumulative effects of removal of land from irrigated agriculture.

Specifically, the goals of the Land Retirement Demonstration Project are to:

• Provide site-specific scientific data to determine if land retirement is an effective

way to reduce drain water volume and provide habitat. Results will guide

implementation of the larger Land Retirement Program;

• Research cost-effective means of restoring self-sustaining communities of native

upland plants and animals on LRDP lands that will be applicable to larger

acreages;

• Use adaptive management principles (Holling 1978, Walters and Holling 1990) to

maximize efficiency of the restoration research program;

• Educate stakeholders about the Land Retirement Program; and

• Evaluate the need for continued use of acquired water on Demonstration Project

lands. If not needed for habitat restoration or continued management of these

lands, USDI may sell the water to another user within the water district or the

water may be used for other CVPIA purposes (USDI 1999).

A resource monitoring plan was prepared by the California State University Stanislaus,

Endangered Species Recovery Program (ESRP). That plan outlined habitat restoration

research and protocols to monitor for potential contamination of wildlife resulting from

the high selenium levels in shallow groundwater, soils, and surface accumulation of water

(Selmon et al. 1999). The research and monitoring described in that plan were

implemented in 1999. A separate monitoring plan was also prepared that describes

sampling and analysis of physical factors including surface water, groundwater, and soils

(CH2M Hill 1999).
Land Retirement Demonstration Program: Year 3

4

C. Demonstration Project Site Locations and

Descriptions

The Demonstration Project consists of project sites in two geographically and

physiographically different drainage-impaired basins, in order to generate data

representative of large-scale land retirement. The Tranquillity site, formerly called the

Westlands site or Mendota site, is located in western Fresno County and will consist of

approximately 7,000 acres. The Atwell Island site, formerly called the Alpaugh site, is

located in Kings and Tulare counties and will be approximately 8,000 acres.

Monitoring of biota, soils, and surface and groundwater depth and quality will be

implemented on the 15,000 acres of Demonstration Project lands as they are purchased.

Currently, a total of 6,114 acres have been purchased. Another 2,641 acres are in escrow

and title transfer is expected in 2002.

1. Tranquillity Site

In the fall of 1998, the Land Retirement Team purchased 1,646 acres in western Fresno

County. An additional 440 acres were added to that site in late 2001 bringing the total to

2,086 acres (Figure 2). An additional 541 acres are currently in escrow and should be

added to the site in 2002. Much of the land initially purchased in 1998 had previously

been in agricultural production. In 1999, a cover crop of barley was planted on

approximately 1,200 acres for weed and erosion control. The remaining acreage had

been idled for longer than 5 years and contained sufficient plant cover. The 440 acre

parcel obtained in late 2001 has been fallowed and grazed, but has not yet been surveyed

for wildlife, or received any restoration efforts. These tasks are scheduled to occur in

2002.
Land Retirement Demonstration Program: Year 3

5

Figure 2. Current configuration of the Tranquillity site.

2. Atwell Island Site

As of February 2002, 4,028 acres had been purchased in Kings and Tulare counties in the

Tulare Basin area near Alpaugh (Figure 3). This includes 1,382 acres acquired during

2001. Approximately 2,100 additional acres are currently in escrow and should be

acquired in the near future, bringing the Atwell Island project area total acquired to

approximately 6,128 acres. The project is authorized to increase to 8,000 acres. Of the

4,028 acres now owned by USBLM, approximately 1,300 acres are currently being

farmed, 1,300 acres have not been farmed for 5 years, and 1,400 acres have not been

farmed for 15 years. Surveys conducted by ESRP in 1998 indicated that several sensitive

species inhabit or use some idled lands that have been purchased at this site (Uptain et al.

1998).
Land Retirement Demonstration Program: Year 3

6

Figure 3. Current configuration of the Atwell Island site.
Land Retirement Demonstration Program: Year 3

7

D. Project scope

The desired outcome for retired agricultural land is drainage reduction and the

reestablishment of self-sustaining upland communities such as California prairie, Valley

Sink Scrub, and Valley Saltbush Scrub (sensu Holland 1986). Because virtually no

information is available on upland community restoration of retired agricultural land in

the Valley, this Land Retirement Demonstration Project provides an opportunity to

develop cost-effective restoration techniques and study the effects of habitat restoration

prior to implementation on a larger scale.

A variety of research, monitoring, restoration, and management activities have been

implemented on retired lands at both the Tranquillity and the Atwell Island sites since

1999. Some of these activities include:

• a study to determine the responses of wildlife to restoration efforts (Habitat

Restoration Study);

• site-wide monitoring of wildlife;

• monitoring of groundwater levels and groundwater quality in relation to reduction

of applied irrigation water;

• restoration-related experimentation to gather information on appropriate uses and

types of cover crops, seeding rates, seeding methods, seedling planting,

microtopographic relief, and mycorrhizal inoculation;

• installation of nurseries to grow locally collected seed;

• implementation of wildlife-friendly farming practices, and;

• management of lands for recreational use.

The following sections of this report describe the accomplishments and preliminary

results obtained by the Land Retirement Team in the calendar year 2001. Study designs

and methodologies are presented whenever necessary for clarity or when changes have

been made from those previously reported.
Land Retirement Demonstration Program: Year 3

8

II. HABITAT RESTORATION STUDY

A. Tranquillity

1. Study Design

An 800 acre Habitat Restoration Study (HRS) was established at the Tranquillity site in

1999 to examine specific techniques of restoring natural habitat. Data are being collected

and analyzed to assess differences between four experimental treatments: restoration

using imprinting with native seeds in combination with surface contouring (installation of

microtopography, CR); restoration using imprinting with native seeds (NR); surface

contouring (CR); and no treatment (NN, Figure 4).

Specific objectives of the HRS are:

• to determine the efficacy of revegetation with native plants as a means to facilitate

upland habitat restoration;

• to determine the efficacy of microtopographic contouring as a means to facilitate

upland habitat restoration;

• to examine the responses of plants and wildlife to habitat changes.

In 1999, 20 10-acre study plots were randomly established within 5 blocks (Figure 4).

Each plot is surrounded by 30 acres that have been maintained with a barley cover crop to

isolate the plots, and to reduce weeds and the occurrence of soil erosion. An average of

4.6 inches of water was applied to the barley using a hand-moved sprinkler irrigation

system in 12-hour sets during the time period from 15 March to 30 April 2001. Barley

was harvested in June 2001. Previous reports (Selmon et al. 1999, Selmon et al. 2000,

and Uptain et al. 2001) describe the installation of the microtopographic contours,

methods of seeding and seedling transplanting, rates of seeding, and the composition of

the seed mix. Supplemental planting or contouring did not occur on the study plots in

2001.
Land Retirement Demonstration Program: Year 3

9

Figure 4. Map of the Tranquillity site showing the randomized block design and

treatments applied to each study plot. CR = contoured and restored, NR = not contoured

but restored, CN = contoured but not restored, NN = not contoured and not restored

(control).

2. Biological Monitoring

Biological monitoring conducted on the Tranquillity HRS plots in the year 2001

consisted of:

• annual vegetation surveys (richness and composition)

• annual invertebrate surveys (sweep and pitfall)

• annual amphibian and reptile surveys
Land Retirement Demonstration Program: Year 3

10

• quarterly avian surveys

• quarterly small mammal surveys

a. Vegetation Surveys

i. Methods

Vegetation surveys were conducted on the Tranquillity HRS plots in May, 2001 (3-4, 9

May). Twenty four vegetation samples (35 cm by 70 cm rectangular quadrats) were

taken from each plot. A stratified random sampling approach was employed, with plots

divided into sixth-sections and four sampling points randomly selected within each

section. All species were noted, and the percent cover contributed by each species was

estimated using a modified Daubenmire cover scale (Bonham 1989). Total percent cover

of all vegetation within the quadrat was also estimated using the same cover scale. When

identification to species level was not possible, species were assigned morpho-species

names (e.g., "unknown Atriplex", "unknown with red cotyledons"). Plant productivity

samples were not collected and will not be collected again until the last year of sampling,

according to defined protocols.

Both digital and panoramic 35 mm photographs were taken on the experimental plots on

(4 Sep, 21, 24 Dec 2001). Copies of the photos are archived at ESRP and USBR offices

in Fresno and will be used to document temporal changes in plot vegetation.

Data were analyzed and presented differently in 2001 compared to 1999 and 2000.

Accordingly, the information in this report supercedes those presented in previous annual

reports (Selmon et al. 2000, Uptain et al. 2001). Descriptive statistics, Student’s t-tests,

and Analysis of Variance (ANOVA) were performed using the software package

STATISTICA (StatSoft, Inc. 1999). In order to simultaneously express floristic

relationships among the Tranquillity study plots and to examine the relationship between

site vegetation and block effect, data were organized into a binary matrix of plots versus

species (recorded as percent cover values) and were ordinated using Detrended

Correspondence Analysis (DCA, Hill and Gauch 1980). Ordinations were conducted

using the software package PC-Ord (McCune and Mefford 1997).

ii. Results

Twenty six species of vascular plants were observed on the Tranquillity HRS plots during

vegetation sampling in 2001 (Appendix A, Table A1). In contrast, 21 species had been

noted in the plots during 1999 sampling, and 31 species in 2000 (Appendix A, Table A1).

Twelve of the species noted on the plots in 2000 were not noted in 2001; conversely,

seven species noted during vegetation sampling in 2001 were not recorded for 2000

(Appendix A, Table A1). The sole species that was noted during vegetation sampling in

1999 and not noted in subsequent years was Sonchus asper (spiny sowthistle), an

introduced species (Appendix A, Table A1). This species is easily confused with another

common weed, Sonchus oleraceus (common sowthistle); hence, its omission in

subsequent years most likely represents a sampling artifact.
Land Retirement Demonstration Program: Year 3

11

Nine of the 26 species noted on the plots during 2001 vegetation sampling were native

(Table 1). Six of these, Bromus carinatus, Hemizonia pungens, Lasthenia californica,

Leymus triticoides, Suaeda moquinii, and Vulpia microstachys, were species that had

been imprinted. Three of the seven species noted in 2001, which were not found in 2000,

were native (Amsinckia menziesii, H. pungens, and L. triticoides; Table A1). However,

none of these were noted in any great abundance, with L. triticoides present in seven

quadrats, and H. pungens and Amsinckia menziesii each noted in a single quadrat

(Appendix A, Table A2). In contrast, 8 of the 12 species that were noted in 2000 but not

in 2001 were native (Table 1). Of these, two (Frankenia salina and Isocoma acradenia;

Table 1) are species that were imprinted. At least one of these perceived absences

(Isocoma acradenia) was clearly an artifact of sampling as mature individuals of this

species, which is a fairly robust shrub, were noted on at least one plot later in the year

(Fall, 2001).

Table 1. Seeded species and additional native species observed on the study plots at the

Tranquillity HRS site. Species marked with an asterisk are those included in the seed

mix.

Species Common name 1999 2000 2001

Allenrolfea occidentalis* Iodine bush - - -

Amsinckia menziesii rancher's fireweed - - +

Asclepias fascicularis narrow-leaved milkweed - +

1

-

Atriplex argentea silver scale + + +

Atriplex polycarpa* valley saltbush - - -

Atriplex spinifera* spiny saltbush - - -

Bromus carinatus* California brome - + +

Eremalche parryi Parry's mallow + + -

Frankenia salina* alkali heath - + -

Heliotropium curassavicum* heliotrope - - -

Hemizonia pungens* common spikeweed - - +

Hordeum depressum alkali barley + + -

Isocoma acradenia* goldenbush - + -

Lasthenia californica* goldfields - + +

Leymus triticoides* creeping wildrye - - +

Malvella leprosa Alkali mallow - + -

Monolepis nuttalliana Nuttall's povertyweed - + -

Phacelia distans common phacelia + + +

Solanum americanum common nightshade - + -

Sporobolus airoides* alkali sacaton - - -

Suaeda moquinii* bush seepweed - + +

Vulpia microstachys* Nuttall's fescue - + +

1. Species noted on the study plots but which did not occur in sampling quadrats.
Land Retirement Demonstration Program: Year 3

12

By all measures, introduced (i.e., non-native) species were far more prevalent than native

species in the Tranquillity HRS plots. When considered in terms of frequency (i.e., the

number of samples in which a species was noted), introduced species were nearly 11

times more abundant than native species (Appendix A, Table A2). When considering

only the imprinted plots (i.e., those plots that would be expected to have the largest

component of native species), introduced species were still more than seven times as

abundant as native species (Table 2). Nearly half of these were attributable to Atriplex

argentea—a non-imprinted native of decidedly questionable value—thus, the number of

desirable native species noted in the plots comprised about 8% of all species occurrences.

Table 2. Frequency of species noted in the imprinted plots during vegetation sampling,

2001. Species marked with an asterisk are those included in the seed mix.

Species Origin Plot

1

Quadrat

2

Atriplex argentea Native 7 39

Avena fatua Introduced 5 17

Beta vulgaris Introduced 2 12

Brassica nigra Introduced 6 39

Bromus carinatus* Native 2 2

Bromus diandrus Introduced 2 2

Bromus madritensis Introduced 4 47

Capsella bursa-pastoris Introduced 6 49

Erodium cicutarium Introduced 2 14

Hemizonia pungens* Native 1 1

Hordeum murinum Introduced 5 48

Hordeum vulgare Introduced 9 81

Lactuca serriola Introduced 8 39

Lasthenia californica* Native 6 15

Leymus triticoides* Native 4 7

Melilotus indica Introduced 6 46

Phacelia distans Introduced 1 5

Phalaris sp. Introduced 2 5

Salsola tragus Introduced 2 7

Sisymbrium irio Introduced 8 138

Sonchus oleraceus Introduced 7 25

Suaeda moquinii* Native 2 2

Vulpia microstachys* Native 4 18

Summed quadrat frequency of introduced species: 569

Summed quadrat frequency of native species: 89

1. Frequency of plots in which a particular species was noted

2. Frequency of quadrats in which a particular species was noted.
Land Retirement Demonstration Program: Year 3

13

When analyzed with respect to the contribution of the species classes to percent cover

(Table 3; Table A3), the dominance of introduced species was more evident. Mean

percent cover of imprinted species ranged from 0.00-1.73% (Table 3). In contrast, mean

percent cover of introduced species ranged from 3.35-78.56%. In both cases, the lowest

percent cover values were from the same plot (Plot 13). This plot was characterized by

an abundance of last year's Atriplex argentea "skeletons" (the persistent stems and

marcescent leaves). These stems tend to limit the germination of other species. This

limiting effect of A. argentea on other plants can be clearly seen in Plot 13, in which 17

of the 24 quadrats were without living vegetation. Many of these samples were noted as

having 50-95% of the quadrat area taken up by the dead A. argentea from the previous

year. Generally, non-imprinted plots supported a higher percent cover of vegetation than

did imprinted plots (Table 3). The differences in mean percent cover were found to be

statistically significant, both between the non-seeded and imprinted treatments (ANOVA

F = 6.408; p = 0.034) and among the five blocks (F = 6.408, p = 0.008).

Table 3. Overview of species grouped by origin at Tranquillity HRS. Values in the cell

represent the estimated site-wide mean percent cover (calculated from the summed cover

data divided by the total number of quadrats). Roman numerals indicate the block in

which the plot was situated, followed by the number of the plot (in parentheses).

Contoured/Imprinted Non-contoured/Imprinted

Origin I II III IV V I II III IV V

(2) (7) (11) (13) (17) (1) (5) (12) (16) (20)

Imprinted 0.02 1.73 0.06 0.00 0.00 0.08 0.98 0.33 0.17 0.00

Native 1.71 0.00 18.90 0.15 0.02 1.54 0.00 3.23 6.29 0.00

Introduced 30.23 15.00 15.90 3.35 36.06 54.10 22.23 17.02 17.71 25.00

Cultivar 0.56 16.31 1.94 0.02 0.15 0.19 13.58 4.48 0.81 0.00

Not Identifiable 0.08 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.0

Total: 32.60 33.04 36.79 3.52 36.23 55.94 36.79 25.06 24.98 25.00

Contoured/Non-Imprinted Non-contoured/Non-Imprinted

Origin I II III IV V I II III IV V

(4) (6) (10) (14) (19) (3) (8) (9) (15) (18)

Imprinted 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Native 0.13 0.00 0.25 0.63 0.00 0.13 0.02 3.56 4.29 0.02

Introduced 60.21 20.63 15.77 22.35 67.73 78.56 24.40 38.88 15.17 54.25

Cultivar 0.19 6.46 6.19 0.15 0.00 0.56 17.60 1.31 0.15 0.00

Not Identifiable 0.13 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.13

Total: 60.65 27.08 22.21 23.13 67.73 79.25 42.04 43.75 19.60 54.40

The effects of variability throughout the study area (i.e., "block effect") can be clearly

seen in the ordinations of the vegetation data (Figure 5). Plots situated in close proximity

in ordination space possess stronger floristic similarities than those situated further apart.

If treatment effects were predominant, it would be expected that plots with the same color

would be grouped in ordination space (i.e., the two dimensional frame in which the data

are plotted). In contrast, if block effects were predominant, it would be expected that
Land Retirement Demonstration Program: Year 3

14

plots with the same shape would be grouped. In the first year of vegetation sampling

(Figure 5), the majority of the study plots were situated in close proximity. This was not

unexpected as the study plots (which had not yet been imprinted) were dominated by

barley. In subsequent years, the plots diverged substantially from their initial positions

(Figure 5). The most evident pattern in the two years following imprinting is a tendency

for plots within the same block to be closely situated in ordination space (Figure 5).

Clearly, the orientation of the plots was influenced to a great degree by physical

differences among the blocks. Another noteworthy pattern was the orientation of plots in

blocks 1 and 5. These were grouped closely by block, with each group constituting one

of the endpoints for Axis 1 (Figure 5). These spatial relationships suggest that blocks 1

and 5 were the most dissimilar, and that treatment effects were minimal in these two

blocks relative to the effects of other factors (e.g., weed load).
Land Retirement Demonstration Program: Year 3

15

Figure 5. Ordinations by Detrended Correspondence Analysis (DCA) of the Tranquillity

HRS plot vegetation. See text for interpretation.
Land Retirement Demonstration Program: Year 3

16

Additional insight into the floristic structure of the study plots is obtained by graphing the

relative abundance of species (i.e., their percent contribution to the total vegetation

present) against their rank (e.g., most abundant, etc.). These "rank abundance graphs"

were generated for the data from the 3 years of vegetation sampling (Appendix B,

Figures B1-B5). These graphs can be interpreted by examining the position (i.e., the

rank) of the various species and also by considering the slope of the plotted line. A

steeper slope suggests dominance by a single species, or by a few species, while a more

gradual slope suggests a tendency towards "evenness" (i.e., a more equitable contribution

from a greater number of species). It is apparent from these graphs (Appendix B, Figures

B1-B5) that in 2000 the seeded plots (i.e., treatments CR and NR) were both more

diverse and tended towards greater evenness than the non-seeded plots (i.e., less likely to

be dominated by a single species). Nevertheless, it is also apparent that in 2001 both

diversity and evenness had diminished from the levels recorded for 2000.

The overall dominance of introduced species also is apparent in the rank abundance

graphs (Figures Appendix B, Figures B1-B5). Only a single study plot in 2000

(Appendix B, Figure B4-a) and in 2001 (Appendix B, Figure B3-a) had a native species

providing the greatest amount of cover. In both cases, the dominant species was Atriplex

argentea, an ‘undesirable’ native.

As might be expected, many of the non-native species noted in the Tranquillity HRS

plots were ruderals. Six of these were included in the CalEPPC list of Pest Plants of

Greatest Ecological Concern (California Exotic Pest Plant Council, 1999; Table 4). Of

these, three species, Avena fatua, Bromus madritensis subsp. rubens and Brassica nigra,

could be described as frequent, with only A. fatua present in any real abundance

(Appendix A, Table A1). Two species, B. madritensis and Convolvulus arvensis (Table

4), were listed as noxious weeds (Class "C") by the California Department of Food and

Agriculture (2001).
Land Retirement Demonstration Program: Year 3

17

Table 4. Known "pest plants" observed in the Tranquillity HRS plots. See key for an

elaboration of their status as weeds.

Frequency3Cover4Site cover5

Species

CalEPPC

Status1 CDFA

Status2

1999 2000 2001 1999 2000 2001 1999 2000 2001

Avena fatua a - 2 4 83 3.00 1.75 15.72 <0.01 <0.01 2.72

Bassia hyssopifolia b - - - 1 - - 0.5 - - <0.01

Brassica nigra b - 39 40 73 3.01 7.91 21.71 0.24 0.66 0.80

Bromus madritensis

subsp. rubens c - 94 89 94 2.80 21.46 32.07 0.55 3.98 6.28

Convolvulus arvensis d c 2 1 - 0.50 0.50 - <0.01 <0.01 -

Salsola tragus e c - - 13 - - 13.96 - - 0.38

1. California Exotic Pest Plant Council (CalEPPC) status: a. Preliminarily listed as an abundant and widespread

grass that may pose significant threat; b. CalEPPC List B. Control required in nurseries, control elsewhere at

the discretion of local County Agricultural Commissioner; c. CalEPPC List A-2. Documented as an aggressive

invader in fewer than 3 Jepson Manual geographic subdivisions; d. Considered but not listed. Plants that, after

review of status, do not appear to pose a significant threat to wildlands; e. Need more information. Plants for

which current information does not adequately describe nature of threat to wildlands, distribution or

invasiveness.

2. California Department of Food and Agriculture (CDFA) status: c. Weeds that are so widespread that the agency

does not endorse state or county funded eradication or containment efforts except in nurseries or seed lots.

3. Frequency: the number of quadrats in which the taxon was noted (out of 480 quadrats sampled per year).

Species with no values listed were those encountered during the Pre-project Inventory (2000) that were not

observed in sampling quadrats during the Baseline survey (2001).

4. Estimated mean percent cover of the taxon calculated from only those quadrats in which the species was noted.

Percent cover values were estimated from midpoints of the cover class (e.g., a species with an estimated cover

of 5-25% was evaluated as having a cover of 15%).

5. Estimated site wide mean percent cover calculated from the summed cover data divided by the total number

(384) of quadrats.

iii. Discussion

Of particular interest, 5 of the 13 species that were imprinted when the study plots were

established (Allenrolfea occidentalis, Atriplex polycarpa, Atriplex spinifera,

Heliotropium curassavicum, and Sporobolus airoides; Table 1), have not been noted

during vegetation sampling. However, the absence of at least one of these species also

was due to random sampling procedures, as numerous individuals of Atriplex polycarpa

were in evidence on many of the imprinted plots. Sampling methodology will need to be

refined for subsequent years, in order to reduce this type of error. Nevertheless, of the

remaining four species no individuals were noted either in the quadrats or elsewhere on

the plots. The poor performance of these species raises the question whether they should

be utilized in future restoration efforts at the Tranquillity HRS site. Nevertheless, it

should be noted that the absence of these species could also be explained by any number

of factors–e.g., poor quality seed, insufficient rainfall, unsuitable soil conditions, etc.

The absence or paucity of a number of these species is puzzling. Allenrolfea occidentalis

is a common and very conspicuous component of remnant areas of non-tilled ground in

the general area of the study site. Yet, it has not been established in either the

Tranquillity HRS study plots nor in the 160-acre restoration in Section 23 (see the Site-
Land Retirement Demonstration Program: Year 3

18

wide Activities section). Furthermore, two different seeding techniques were used for

this species, with the seed imprinted in the study plots and hand broadcast following the

imprinting of other species at Section 23 (see Uptain et al. 2000). As with other members

of the Chenopodiaceae (Khan et al. 2002), A. occidentalis is generally more successfully

established if some treatment is applied to help break dormancy (Gul and Weber 1997).

Additionally, we have observed that, in natural habitats, Atriplex species seem to require

the correct combination of circumstances to achieve germination. It may very well be

that the dry conditions that have characterized the initial three years of the Habitat

Restoration Study have been the principal factor limiting Atriplex establishment in the

study plots.

The dearth of Hemizonia pungens, (i.e., noted in a single sample) is of particular interest.

This species is extremely abundant in various remnant native habitat patches in the

Tranquillity area, and germinates sufficiently early in the growing season to be capable of

competing with the weeds at the HRS site. Additionally, an examination of historic

records and existing relict vegetation in the San Joaquin Valley indicated that tarweeds

(i.e., Holocarpha spp. and Hemizonia spp.) were dominant in low precipitation areas and

on infertile soils (Holstein 2001). The absence of Heliotropium curassavicum is similarly

confounding, as this species is very common in disturbed habitats (e.g., roadsides, edges

of fields) throughout the general HRS area. Yet, despite the high degree of disturbance

associated with soil preparation and imprinting, H. curassavicum has yet to be noted in

any of the areas in which it has been imprinted. In both cases, the failure of these species

to become established may well be attributable to their ecotype having originated from

outside the San Joaquin Valley, but we lack sufficient information on seed sources to

state this with certainty.

The general impression from the initial vegetation sampling of the imprinted study plots

(i.e., 2000) was that the restoration efforts had been reasonably successful (Uptain et al.

2001). However, based on this year's sampling it appears that the success of the

restoration may be ephemeral. Some species that appeared to be well-established in 2000

(e.g., Bromus carinatus, Lasthenia californica and Vulpia microstachys) diminished in

both frequency and percent cover by the following year's sampling. Additionally, we had

hoped that a portion of the seeds that had been imprinted but which did not germinate in

2000 would persist in the seed bank and germinate during the subsequent year (sensu

Heady 1977). This does not seem to have been the case, as only two imprinted species—

Hemizonia pungens and Leymus triticoides—were more abundant in 2001 than in 2000.

However, in both instances, these species were rarely encountered (H. pungens in one

quadrat; L. triticoides in seven quadrats); hence, it does not appear that there was any

significant germination of seeds in the year following imprinting. Nevertheless, it should

also be noted that both 2000 and 2001 were poor years for native plant production

throughout the southern San Joaquin Valley (E. Cypher, pers. com.). Therefore, it may

well be that viable seeds from imprinting remain in the seed bank, and that these will be

able to become established if appropriate weather conditions occur in 2002.

We also observed in 2000 that some native species that hadn’t been included in the seed

mix (e.g., Asclepias fascicularis) had become established as volunteers on the study plots

(Uptain et al. 2001). With the exception of the undesirable tumbleweed, Atriplex
Land Retirement Demonstration Program: Year 3

19

argentea, there was little evidence that non-imprinted native plant species were becoming

established on the study plots in 2001.

b. Invertebrate Surveys

i. Methods

Pitfall sampling to determine invertebrate richness and abundance was conducted from

20-22 June, 2001. Invertebrates were collected from 20 pitfalls configured in 5 arrays on

each of the 20 study plots. The methods used to collect pitfall samples are described in

previous reports (Selmon et al. 2000, Uptain et al. 2001). Because there were some

corrections made to the information contained in the invertebrate databases, the

information in this report supercedes that which was presented in previous annual reports

(Selmon et al. 2000, Uptain et al. 2001).

The vertical structure of the vegetation on many study plots has developed sufficiently to

provide habitat for invertebrates. Pitfall sampling adequately samples ground-dwelling

invertebrates, but it does not adequately sample invertebrates occupying this upper tier of

vegetation. To rectify this, sweep sampling for invertebrates was added to the HRS

sampling protocols in August 2000 to gather richness, abundance, and composition

information for these invertebrates. Methods used to collect sweep samples were

presented in Uptain et al. (2001). Sweep sampling was conducted on 30 April; 1, 7 and

30 May; 25 June; and 10-11 September 2001. Those data are currently being sorted,

identified, and added to the database. Accordingly, the information presented below does

not include results of the sweep sampling effort, but rather, richness, abundance, and

composition is based solely upon invertebrate collections from pitfalls.

ii. Results

Invertebrate richness did not vary by treatment in any year, nor did richness vary among

any given year across treatments (Figure 6). However, some trends are apparent. There

was a trend of lower richness for all treatments 2000, in 1999 the non-contoured but

restored plots (NR) had the highest richness, and in 2001 the control plots had the highest

richness. Mean abundance of invertebrates did not vary by treatment, except in 2001

where the contoured but non-restored plots had the fewest invertebrates (Figure 7). For

most treatments, there was a trend of increasing invertebrate abundance from 1999 to

2000, then decreasing abundance in 2001.
Land Retirement Demonstration Program: Year 3

20

Figure 6. Invertebrate richness (generated from pitfall data) by treatment at the

Tranquillity site.

Figure 7. Invertebrate abundance (generated from pitfall data) by treatment at the

Tranquillity site.
Land Retirement Demonstration Program: Year 3

21

There were differences in invertebrate richness and abundance among the blocks (Figures

8 and 9). The most notable differences in richness were that block 1 had greater richness

than any other block during all years and that block 3 had a relative low richness in 2000.

Abundance among the blocks were most similar in 1999 and most variable in 2001,

indicating that blocking effect is increasing. Furthermore, there is no defined pattern of

blocking effect on abundance that is consistent through the years (i.e., certain blocks do

not tend to remain higher or lower in abundance than other blocks from year to year).

However, the total number of invertebrates collected over the 3-year period was less on

blocks 1 and 5 than on the other three blocks.

Figure 8. Invertebrate richness by block at the Tranquillity (TR) site.
Land Retirement Demonstration Program: Year 3

22

Figure 9. Invertebrate abundance by block at the Tranquillity (TR) site.

Invertebrate composition exhibited temporal changes (Table 5). Thysanoptera dominated

the invertebrate population in 1999 whereas Hemiptera and, secondarily, Thysanoptera

dominated in 2000. In 2001 Orthoptera was dominant. Although there were just a few

orders that were dominant in each year, there was a trend towards increasing evenness

from 1999 to 2001 (Table 5).

Table 5. Composition (abundance of each order divided by total abundance) of

invertebrates collected in pitfall traps at the Tranquillity site, 1999 to 2001.

Order 1999 Composition 2000 Composition 2001 Composition

Araneae 12.02% 6.12% 15.87%

Coleoptera 11.63% 2.01% 7.42%

Dermaptera 6.56% 1.11% 0.50%

Hemiptera 1.25% 43.50% 1.26%

Homoptera 0.01% 0.00% 13.91%

Isopoda 0.88% 6.42% 8.66%

Orthoptera 2.81% 11.22% 43.04%

Thysanoptera 64.07% 25.75% 4.19%

Other 0.77% 3.87% 5.15%

iii. Discussion

We suspect that the decline in richness in 2000 was due to a rapid change in the weather

as spring progressed. The spring of 2000 was long and cool, rapidly shifting to a hot
Land Retirement Demonstration Program: Year 3

23

summer. When the scheduled sampling was finally conducted, invertebrate richness had

likely declined from earlier in the season. There was a trend toward increasing evenness

in the invertebrate communities over the blocks, however. We are not surprised that

there was an increase in blocking effect in 2000 and 2001 over that observed in 1999

because in 1999, all blocks were planted in barley and should have been relatively similar

in vegetative structure. We expect, however, that as communities develop on the site

over time that any remaining blocking effects will be due to edaphic differences among

blocks.

c. Reptile and Amphibian Surveys

i. Methods

In previous years, reptiles and amphibians were only sampled in conjunction with the

invertebrate pitfall sampling and by incidental observations. In 2001, we augmented this

approach by walking 2 transects and monitoring 4 cover boards on each plot (Figure 10).

These surveys were conducted on 11-13 July 2001; focused surveys for amphibians were

scheduled for December 2001, but were cancelled due to poor weather conditions

precluding access to the site.
Land Retirement Demonstration Program: Year 3

24

Figure 10. Locations of pitfall arrays, sweep transects, cover boards, avian transects, and

small mammal trapping lines on Tranquillity HRS plot.

ii. Results

No reptiles or amphibians were found during the 3-day focused surveys, nor were any

found in the pitfall arrays. There was one unconfirmed sighting of a western fence lizard

(Sceloporus occidentalis) on Plot 7 and a confirmed sighting of a California king snake

(Lampropeltis getulus californiae) on Plot 4. Both of these sightings occurred in April

2001. Numerous western toads (Bufo boreas) and 1 California king snake were observed

off of the research blocks while conducting site-wide surveys (see section III A 2).

iii. Discussion

For a variety of reasons it is not surprising that amphibians and reptiles still are absent

from the research plots. Some of these are:
Land Retirement Demonstration Program: Year 3

25

• after two years, the study plots contain habitat that is minimally suitable for

reptiles and amphibians

• the study plots are isolated by large buffer areas of barley, making access to the

plots by reptiles and amphibians from surrounding areas problematic

• the small size of the study plots relative to the habitat needs of some reptiles and

amphibians may limit the number of species able to colonize the study plots

• there is little remaining habitat for reptiles and amphibians in the vicinity of the

study plots, which presumably has resulted in depressed populations throughout

the area

The most common amphibian in the vicinity is the western toad. This species would

seem be the most likely candidate to colonize the study plots. However, with the

reduction in irrigation water and the lack of moisture, the plots are minimally suitable for

this species. Accordingly, we do not expect to record a high abundance of western toads

on the study plots.

d. Avian Surveys

i. Methods

Bird surveys were conducted on each plot on a quarterly basis to determine seasonal

avian richness, abundance, and composition. Sampling was conducted on 17-19 January,

18-20 April, 18-20 July, and 2-4 October 2001. Methods used for sampling follow those

presented in previous reports (Selmon et al. 2000, Uptain et al. 2001).

ii. Results

A total of 28 species was observed on the study plots in 2001. Avian species richness

ranged from 1.0 to 6.4 and mean abundance of individuals ranged from 0.13 to 154.3 in

2001. Both richness and abundance showed high variation by season with high values

for both categories occurring in the winter (Figures 10 and 11). No differences were

detected between treatments for either species richness or mean abundance in 2001.
Land Retirement Demonstration Program: Year 3

26

Figure 11. Avian richness by season at the Tranquillity site.

Figure 12. Avian abundance by season at the Tranquillity site.
Land Retirement Demonstration Program: Year 3

27

Mean abundance and species richness also were examined across years. Mean

abundance consistently increased across treatments from 1999 to 2001 in the spring, and

from 2000 to 2001 in the winter. This was concomitant with an increase in species

richness for the same time period. The mean total abundance was consistently lower

across treatments in the fall of 2001 than in the previous 2 years.

Six species of special concern in California (CSC) or federal special concern species

(FSC) were observed on the study plots. Short-eared owls (Asio flammeus) (CSC)

showed a dramatic increase in abundance in 2001. Only a few individuals had been

reported in the previous 2 years, but in 2001 this species ranked within the top five most

abundant birds for the summer season (Table 6). This species was breeding on one of the

control plots, where it was most frequently observed. However, short-eared owls also

were observed on plots with all other treatments. Burrowing owls (Athene cunicularia)

(FSC, CSC) were not observed on any plots in 1999 or 2000, but one individual was

observed occupying a burrow on a control plot in 2001. Northern harriers (Circus

cyaneus) (CSC) also showed an increasing population trend and were confirmed to be

breeding on the plots. One species of special concern, the horned lark (Eremophila

alpestris) appears to have declined on the study plots since 1999.
Land Retirement Demonstration Program: Year 3

28

Table 6. Avian relative abundance and ranked species composition on the Tranquillity

site study plots, 1999 to 2001.

Winter 1999 Winter 2000 Winter 2001

Species1 R.A.2 Rank3 Species1 R.A.2 Rank3 Species1 R.A.2 Rank3

BRBL 50.80 1 SAVS 49.80 1

SAVS 9.63 2 BRBL 19.65 2

N/A MOPL 8.02 3 WEME 17.41 3

LBCU 6.95 4 RWBL 3.62 4

AMKE 5.88 5 WCSP 2.82 5

Spring 1999 Spring 2000 Spring 2001

Species1 R.A.2 Rank3 Species1 R.A.2 Rank3 Species1 R.A.2 Rank3

RWBL 54.58 1 RWBL 77.59 1 RWBL 77.34 1

BRBL 18.33 2 BRBL 10.82 2 SAVS 9.27 2

YHBL 8.33 3 WEME 6.73 3 WCSP 3.92 3

WEME 6.67 4 MALL 0.99 4 SOSP 3.59 4

MALL 3.33 5 CLSW 0.66 5 WEME 2.06 5

NOHA 0.66 5

RNPH 0.66 5

SAVS 0.66 5

Summer 1999 Summer 2000 Summer 20001

Species1 R.A.2 Rank3 Species1 R.A.2 Rank3 Species1 R.A.2 Rank3

AMKE 21.74 1 WEME 57.94 1 WEME 25.64 1

WHIM 17.39 2 RWBL 19.63 2 BARS 17.95 2

WEME 15.22 3 WTKI 3.74 3 NOHA 17.95 2

CORA 8.70 4 AMKE 2.80 4 WTKI 15.38 3

NOHA 8.70 4 BAOW 2.80 4 LOSH 7.69 4

LOSH 6.52 5 BARS 2.80 4 SEOW 7.69 4

WEKI 2.80 4 WEKI 5.13 5

CORA 1.87 5

SOSP 1.87 5

Fall 1999 Fall 2000 Fall 2001

Species1 R.A.2 Rank3 Species1 R.A.2 Rank3 Species1 R.A.2 Rank3

AMPI 24.71 1 SAVS 64.68 1 SAVS 46.01 1

WEME 22.46 2 WEME 21.11 2 WEME 42.02 2

SAVS 19.25 3 RWBL 3.13 3 SOSP 2.66 3

BRBL 13.37 4 WTKI 2.51 4 HOLA 1.60 4

HOLA 11.66 5 BRBL 2.30 5 WCSP 1.60 4

BRBL 1.33 5

 1. Key to avian codes: AMKE , American Kestrel; AMPI, American Pipit ;BAOW, Barn Owl; BARS, Barn Swallow;

BRBL, Brewer's Blackbird; CORA, Common Raven; HOLA, Horned Lark; LOSH, Loggerhead Shrike; NOHA,

Northern Harrier; RWBL, Red-winged Blackbird; SAVS, Savannah Sparrow; SEOW, Short-eared Owl; SOSP,

Song Sparrow; WCSP, White-crowned Sparrow ;WEKI, Western Kingbird; WEME, Western Meadowlark;

WHIM, Whimbrel; WTKI, White-tailed Kite.

 2. Relative abundance (R.A.) is the percent contribution of a single species to total abundance for all study plots.

 3. Rank is sorted in ascending order (most to least abundant) with only the five highest ranked species listed.
Land Retirement Demonstration Program: Year 3

29

iii. Discussion

The majority of the avian species (59%) recorded on the study plots are considered to be

grassland specialists (Appendix B). Grassland specialists are separated into two

categories: obligate grassland specialists, which are exclusively adapted to and entirely

dependent on grassland habitats, and facultative grassland specialists, which are not

entirely dependent on grasslands but use them commonly (Vickery et al. 1999). Nine

avian species on the study plots are categorized as obligate grassland specialists and 13 as

facultative grassland specialists. The development of a more complex plant community

on LRDP lands has been accompanied by changes in the avian community dynamics.

Many of the grassland specialists have increased in numbers following the cessation of

cultivation and the establishment of permanent herbaceous cover.

Species composition shifted seasonally (Figure 13). Blackbirds (Brewer’s and redwinged blackbirds)(Euphagus cyanocephalus, Agelaius phoeniceus) predominated in

winter and spring, western meadowlarks (Sturnella neglecta) generally predominated in

summer, and savannah sparrows (Passerculus sandwichensis) and western meadowlarks

predominated in the fall. Large mixed-species flocks of 500 or more blackbirds were

frequently seen in the barley and on the plots during the winter 2001 census. Flocks of

this magnitude were not observed in 1999 and only occasionally during 2000. These

mixed flocks were generalized as "blackbirds" because of the large numbers and an

inability to reliably distinguish composition. Accordingly, they were not included in the

rank abundance table (Table 6) or in the seasonal relative abundance figure (Figure 13).

Although not shown graphically or in tabular form, Brewer’s and red-winged blackbirds

increased exponentially in abundance in 2001. It is likely that the increase of these

facultative grassland specialists is a result of the barley cover crop that is maintained in

the buffers and the lack of cultivation on the study plots. Savannah sparrows and western

meadowlarks, two obligate grassland specialists, showed a similar response to changes in

vegetative cover. Both have been more prevalent on the study plots since 1999.
Land Retirement Demonstration Program: Year 3

30

Figure 13. Seasonal relative abundance of selected avian species at the Tranquillity site.

Only two grassland specialists appear to have decreased in abundance on the study plots.

Horned larks and American pipits (Anthus rubescens) were both present in relatively high

numbers in 1999, but have since declined. Horned larks and American pipits prefer open

areas with short vegetation or bare ground for both breeding and wintering habitats

(Beason 1995, Kauffman 1996). The dense tall cover of London rocket (Sisymbrium

irio) and barley (Hordeum vulgare) probably made most of the study plots unsuitable for

both of these species. Nevertheless, they are still frequently recorded in the cultivated

buffer region surrounding the plots.

Relative abundance values for the spring season of 2001 were consistently higher across

all treatments than for either of the two previous spring seasons. In contrast, relative

abundance for the fall season of 2001 was consistently lower across all treatments than

for the previous two fall seasons. This disparity may be the result of annual fluctuations

in the timing of migration. Decreasing day length along with weather conditions

stimulates fall migration departures (Gill 1995). It seems likely that the 2001 fall census

may have occurred in the transitional period subsequent to the departure of the fall

migrants, but prior to the arrival of the wintering species.
Land Retirement Demonstration Program: Year 3

31

e. Small Mammal Surveys

i. Methods

Small mammal trapping was conducted on each plot on a quarterly basis to determine

seasonal richness and abundance of species. Trapping was conducted on 27 February-2

March; 30 April-3 May; 6-9 August; and, 5-8 November, 2001. Sherman live-traps were

used for and trapping methods followed those presented in previous reports (Selmon et al.

2000, Uptain et al. 2001). Additionally, small mammals (especially shrews) were

sampled using the pitfall traps established for sampling invertebrates.

ii. Results

During nocturnal live-trapping in 2001, a total of 2,362 small mammals were captured on

the experimental plots. A total of 2,314 deer mice (Peromyscus maniculatus), 46 house

mice (Mus musculus), one western harvest mouse (Reithrodontomys megalotis), and one

California vole (Microtus californicus) were captured.

A trend of increasing small mammal abundance across all years during each sampling

season (Figure 14) was observed. This was especially apparent in the number of captures

of deer mice. As winter data were collected only in 2001, it is not yet possible to discuss

trends for this season.

Figure 14. Abundance of small mammals by season at the Tranquillity site.

Plots receiving treatments generally had greater numbers of small mammals than did the

control plots (Figure 15). During most seasons, small mammal abundance tended to be

greater on the contoured and restored plots (CR) than on the plots that only received
Land Retirement Demonstration Program: Year 3

32

contouring (CN). This holds true for all seasons and years except fall of 1999 (which

preceded treatment installation) and fall of 2000. Because deer mice comprised

approximately 98% of all captures of small mammals, these trends essentially were only

representative of the deer mouse population. The type of treatment appeared to have no

effect on house mice abundance. House mice were captured only on the control plots in

every season, and their abundance did not seem to be correlated with treatment. The one

western harvest mouse was captured on a plot that was seeded with native plants, and the

only vole was captured in a plot treated with contouring.

Figure 15. Abundance of small mammals by treatment at the Tranquillity site.

Small mammal abundance varied by block, especially in 1999 and 2000. In 2001, block

effects diminished, with the exception of Block 1, which had consistently low numbers of

small mammal throughout all years (Figure 16).
Land Retirement Demonstration Program: Year 3

33

Figure 16. Abundance of small mammals by block at the Tranquillity site.

All of the ornate shrews (Sorex ornatus) and most of the voles (Microtus californicus)

were captured in pitfall traps. A total of 25 shrews and 37 voles were captured in 2001

(Table 7). Most of the shrews (88%) were captured on plots that were seeded with native

plants. That trend also held true for shrews captured in 2000, when 67% of shrews were

captured on seeded plots (Table 7), but the trend did not hold true for 1999 (prior to the

treatments being established). By contrast, 62% of the voles that were captured in 2001

were captured on contoured plots and 38% of the voles were captured from seeded plots.

In 1999 and 2000, vole captures were not numerous enough for an evaluation of

treatment effects.
Land Retirement Demonstration Program: Year 3

34

Table 7. Shrews and voles captured in pitfall traps on the Tranquillity site study plots,

1999 to 2001.

Year Species Common name Plot treatment 1 Number captured

CR 1

CN 10

NR 2

Sorex ornatus Ornate shrew

NN 1

CR 1

CN 1

NR 1

1999

Microtus

californicus California vole

NN 0

CR 7

CN 3

NR 5

Sorex ornatus Ornate shrew

NN 3

CR 0

CN 0

NR 0

2000

Microtus

californicus California vole

NN 0

CR 11

CN 0

NR 11

Sorex ornatus Ornate shrew

NN 3

CR 4

CN 19

NR 10

2001

Microtus

californicus California vole

NN 4

1. Key to plot treatments: CR, contoured and restored plots; CN, contoured and non-restored plots; NR, not

contoured and restored plots; NN, not contoured and not restored plots

iii. Discussion

Deer mice are a pioneering species (Zeiner et al. 1990), i.e., a species that occurs in

relatively high numbers in the early seral stages of secondary succession. Hence, it is not

surprising that their numbers have increased dramatically on the study plots. Typically,

deer mice may have home ranges of up to 10 acres (Stickel 1968), but based upon the

abundance encountered, home ranges are probably much smaller on the Tranquillity HRS

study plots. The high density of deer mice probably can be attributed to an abundant

food supply on the plots as well as in adjacent buffers and a lack of periodic disturbance.

As the plant community develops on the sites we would expect the deer mouse
Land Retirement Demonstration Program: Year 3

35

population to decline and other species such as harvest mice, shrews, voles, and kangaroo

rats to become more abundant. As fossorial species (especially gophers, kangaroo rats,

and ground squirrels) become established, additional niches would be created and would

become available for a wide variety of vertebrate and invertebrate species.

It is not surprising that all captures of shrews were in pitfalls. The bait used in live-traps

generally does not attract shrews, whereas invertebrates in the pitfalls provide auditory

and olfactory cues for shrews (Churchfield 1990) and an attractive food source.

Although the captures in pitfalls provide an index of abundance of shrews on the study

plots, a mark-recapture study could provide statistical estimates of abundance and

density, assuming sufficient numbers of shrews and multiple captures of the same

individuals. Nevertheless the increase in the abundance of shrews on the plots and the

seeming tendency of shrews to prefer plots that were seeded with native vegetation are

important observations, another observation may prove to be as important. Shrews were

relatively abundant on the plots in 1999 prior to treatment installation. This indicates that

shrews may have been present on the site during years of agricultural production prior to

the HRS study. If this is the case, then ornate shrews may be more abundant and

widespread in the San Joaquin Valley than was previously thought.

That voles also were captured more frequently in pitfalls than in live-traps is not

surprising. Increases in vole abundance also were observed, especially in 2001, and

affinities for certain plot treatments were noted (see Table 7). The most voles were found

on plots that were contoured but not restored by seeding with native plants.

The first capture of a western harvest mouse was in 2001. That capture was on a plot that

was seeded with native vegetation. This was not surprising given the affinity of the

western harvest mouse to feed on native vegetation (Ingles 1947). We expect western

harvest mice to become more abundant on the plots as the land is left undisturbed. The

value of undisturbed lands to all small mammal populations is apparent from our data.
Land Retirement Demonstration Program: Year 3

36

B. Atwell Island

1. Study Design

The study design for the Habitat Restoration Study at Atwell Island is similar to that at

Tranquillity, but differs in some important aspects. At Atwell Island there are 3

replicated blocks, each containing 16 experimental plots (Figure 17). A representation of

the configuration of a study block is shown in Figure 18. The plots are 2 acres in size,

each nested within a 10-acre parcel. As with Tranquillity, the areas between plots are

maintained with a barley cover crop to isolate the plots. Four treatments were applied to

the plots in winter 2001: seeding with native plants and contouring, seeding with native

plants only, contouring only, and no treatment. The treatments were randomized within

blocks of four plots configured in a 2 by 2 grid.

Figure 17. Map of the Atwell Island site showing the randomized block design.
Land Retirement Demonstration Program: Year 3

37

Figure 18. Map of an experimental block at the Atwell Island site showing the

placement of treatments plots.

Microtopographic contours (berms) were installed on 4-6 December (Block 1), 7-9

December (Block 2), and 10-12 December (Block 3). Contours are of the same general

size and shape as those that were installed on the plots at the Tranquillity HRS site.

However, there are fewer contours on plots at Atwell Island (49 contours per plot) than

there are on plots at Tranquillity site (240 contours per plot) because of the much smaller

plot size. Native plant seeding at Atwell Island was conducted on 27 December (Block

1), 18-19 December (Block 2), and 19 December (Block 3). Seeding was accomplished

using an imprinter; the seed mix and seeding rate were identical to that used on the

Tranquillity HRS site (see Selmon et al. 2000 and Uptain et al. 2001). However, the

locations where seeds were collected differed somewhat between the two sites and in

neither trial were seeding rates standardized for germination and purity. Because of the

low success rate and high cost of planting seedlings on the Tranquillity HRS plots, no

seedlings were planted on the Atwell Island plots.

2. Biological Monitoring

Baseline biological surveys was conducted on the Atwell Island HRS plots in 2001 prior

to treatment application and while the barley cover crop was still in place. Surveys

consisted of:

• vegetation surveys (composition and cover)

• invertebrate surveys (sweep and pitfall)
Land Retirement Demonstration Program: Year 3

38

• amphibian and reptile surveys

• avian surveys

• small mammal surveys

HRS survey methods, results and discussions are presented in the following sections. No

temporal comparisons can be made at this time because only baseline data have been

gathered. Results of the site-wide survey efforts are presented in the Site-Wide Activities

section.

a. Vegetation Surveys

i. Methods

In April 2000, a pre-project inventory was undertaken on the Atwell Island property.

Based on recent land use patterns (Uptain et al., 2001), three distinct areas were identified

at the site (Figure 19). Lists of all observed vascular plant species were compiled for

each area (Appendix A, Table A4). Subsequently, two of the three HRS study blocks

were positioned on areas that had been surveyed (blocks 2 and 3; Figure 19). The area on

which the third HRS study block (Block 1; Figure 19) was established was previously in

agricultural production. As such, the area did not support a significant native flora.

Figure 19. Locations of research areas at the Atwell Island site.
Land Retirement Demonstration Program: Year 3

39

Baseline vegetation sampling was conducted on the Atwell Island HRS plots in May,

2001 (3-4, 9 May). Eight vegetation samples (35 cm by 70 cm rectangular quadrats)

were taken from each plot. Stratified random sampling was employed, with plots divided

into quarters and two sampling points chosen at random from within each quarter-plot.

All species were noted, and the percent cover for each species was estimated using a

modified Daubenmire cover scale (Bonham 1989). Total percent cover of all species

within the quadrat was also estimated using the same cover scale. Whenever possible,

species were identified completely; failing this, species were assigned morpho-species

names.

To document temporal changes in the study plot vegetation, photopoints were established

along the southern midline of the plots where digital and 35 mm panoramic photographs

were taken. Initial photos were taken on 13 June, 2001; subsequent photo sampling will

occur approximately quarterly. Copies of all photos are archived at the ESRP and USBR

offices in Fresno.

ii. Results

Thirty-two species of vascular plants were observed on the Atwell Island site during the

2000 pre-project inventory (Columns A-C; Appendix A, Table A4). Of these, all but two

species, Allenrolfea occidentalis and Tamarix parviflora, were present in the general

areas on which the HRS plots were subsequently installed (i.e., areas A and B; Figure

19). The following year, 49 taxa were noted during baseline sampling of the HRS plots

(Appendix A, Table A4). Of these, 26 were completely identified, 9 were identified to

the level of genus, 4 to the level of family, and the remaining 10 were identified by

morpho-species names.

As expected, Hordeum vulgare (Barley) was ubiquitous and abundant, being present in

all quadrats and possessing the largest average percent cover of all species (Appendix A,

Table A4). An additional six species, Hordeum murinum, Melilotus indica, Phalaris

minor, Amsinckia menziesii, Avena sativa, and Erodium cicutarium, were present in at

least a quarter of the study quadrats. Of these, only A. menziesii is native (Appendix A,

Table A4). Of the 30 species whose origin could be ascertained, 24 were introduced

while only 6 were native (Appendix A, Table A4). By all measures, introduced species

were far more prevalent than native species in the Atwell Island HRS study plots (Figure

20).
Land Retirement Demonstration Program: Year 3

40

Figure 20. Differences in abundances between introduced and native species on the

Atwell Island HRS plots. 1. Occurrences: Mean Frequency— the mean number of

quadrats in which a species was noted; for the abundance estimates, the estimated percent

cover; Mean % Cover I—Estimated average percent cover of the taxon calculated from

only those quadrats in which the species was noted; Mean % Cover II—Estimated sitewide average percent cover calculated from the summed cover data divided by the total

number (384) of quadrats.

Excluding barley, thirteen species noted during baseline sampling were not observed

during the pre-project inventory. The status of an additional sixteen species was

uncertain, due to their identity not being completely known. Also of note, eleven of the

thirty species observed in areas B and C during the pre-project inventory were not

observed in the HRS plots during baseline sampling (Appendix A, Table A4).

To compare conditions at the Atwell Island HRS during its "baseline" year to those at the

Tranquillity HRS during its baseline year, the 20 most abundant species from each site

were tabulated and graphed (Figure 21; Table 81⁄2). The ten most abundant species in the

Tranquillity HRS plots are labeled sequentially. The ten most abundant species in the

Atwell Island HRS plots are also numbered sequentially; however, if a species was also

among the ten labeled Tranquillity species, the number used for the Tranquillity data was

applied to the plot of the Atwell Island data. For example, the second most abundant

species at Atwell Island (Avena sativa) was not among the ten most abundant species at

Tranquillity; hence, it was assigned its own number (11; Figure 21). In contrast, H.

murinum, the fourth most abundant species at Tranquillity was the third most abundant
Land Retirement Demonstration Program: Year 3

41

species at Atwell Island, and hence was identified by a "4" in the plot of the Atwell Island

Rank-Abundance data (Figure 21).

Figure 21. Rank-abundance of baseline plant species data from the Tranquillity (1999)

and Atwell Island (2001) Habitat Restoration Studies, showing the 20 species with the

greatest average abundance for each site. Only the ten most abundant species at each site

were assigned numeric labels. Numbers pertain to species listed in Table 8.
Land Retirement Demonstration Program: Year 3

42

Table 8. The ten most abundant species at the two HRS sites during baseline sampling.

Species are presented in descending abundance for each site. Abundance values are

based on average percent cover in quadrats.

Code1 Tranquillity Site Code1 Atwell Island Site

1 Hordeum vulgare (Barley) 1 Hordeum vulgare (Barley)

2 Sisymbrium irio 11 Avena sativa

3 Bromus madritensis subsp. rubens 4 Hordeum murinum

4 Hordeum murinum 5 Melilotus indica

5 Melilotus indica 12 Phalaris minor

6 Capsella bursa-pastoris 13 Medicago polymorpha

7 Beta vulgaris 14 Erodium cicutarium

8 Brassica nigra 15 Bassia hyssopifolia

9 Senecio vulgaris 16 Amsinckia menziesii

10 Sonchus sp. 17 Polygonum sp.

1. Codes apply to Figure 21

The dominance of barley during the first year of sampling in the HRS study plots can be

clearly seen for both Tranquillity and Atwell Island (Figure 21). The two sites shared

few floristic similarities beyond the abundance of barley. The second and third most

abundant species at the Tranquillity HRS—Sisymbrium irio and Bromus madritensis

subsp. rubens—were present at the Atwell Island HRS, but were ranked much lower

(11th and 15th, respectively). Avena sativa, the second most abundant species at the

Atwell Island HRS (Figure 21), was not noted at the Tranquillity HRS during baseline

vegetation sampling. The fourth and fifth most abundant species at the Tranquillity

HRS—Hordeum murinum and Melilotus indica—also were present at the Atwell Island

HRS; however, their abundances at the latter were much lower (11th and 15th ranked

species, respectively).

In all, 7 of the 10 most abundant species at the Atwell Island HRS were not among the 10

most abundant species at the Tranquillity HRS site (Figure 21). At both sites, introduced

species were far more prevalent than native species (Figure 20; Figure 21). This is

clearly demonstrated by the absence of all but one native species (Amsinckia menziesii)

among the ten most abundant species at either site (Figure 21).

As with the Tranquillity HRS site, many of the non-native species in the Atwell Island

HRS plots were ruderals. Four of these were included in the CalEPPC list of Pest Plants

of Greatest Ecological Concern (California Exotic Pest Plant Council, 1999; Table 9).
Land Retirement Demonstration Program: Year 3

43

Table 9. Known "pest plants" observed in the Atwell Island HRS Plots. See key for an

elaboration of their status as weeds.

Species CalEPPC Status1 Freq.2 Cover3 Site cover4

Bassia hyssopifolia b 12 26.9 0.84

Brassica nigra b 8 4.2 0.09

Bromus diandrus a 11 2.1 0.06

Bromus madritensis subsp. rubens c 50 0.8 0.10

1. California Exotic Pest Plant Council (CalEPPC) status: a. Preliminarily listed as an abundant and widespread

grass that may pose significant threat; b. CalEPPC List B—control required in nurseries, control elsewhere at

the discretion of local County Agricultural Commissioner; c. CalEPPC List A-2—documented as an aggressive

invader in fewer than three Jepson Manual geographic subdivisions.

2. Frequency: the number of quadrats in which the taxon was noted. Species with no values listed were those

encountered during the Pre-project Inventory (2000) that were not observed in sampling quadrats during the

Baseline survey (2001).

3. Estimated mean percent cover of the taxon calculated from only those quadrats in which the species was noted.

Percent cover values were estimated from midpoints of the cover class (e.g., a species with an estimated cover

of 5-25% was evaluated as having a cover of 15%).

4. Estimated site-wide mean percent cover calculated from the summed cover data divided by the total number

(384) of quadrats.

Of the listed species, only two–Bromus madritensis subsp. rubens and Bassia

hyssopifolia–could be described as frequent, with only B. hyssopifolia present in any real

abundance (Table 9). No species observed in the Atwell Island HRS plots were among

those listed as noxious weeds by the California Department of Food and Agriculture

(2001).

iii. Discussion

We do not know if species observed in areas B and C during the pre-project inventory,

but not observed on the HRS plots during baseline sampling were excluded from the site

or if their absence was merely short term (due to lack of appropriate conditions for

germination and growth) or longer-term (due to extirpation). This should be discernable

with future sampling. Seven of the 11 species were native (Appendix A, Table A4);

two—Heliotropium curassavicum and Isocoma acradenia—represent taxa that are

included in the restoration seed mix. This suggests that they are unsuitable for inclusion

in the early stages of restoration; yet, because abundance data were not recorded during

the pre-project inventory, these species may have been present in low abundance. If this

were the case, their absence during baseline sampling would not be unexpected.

However, it is also necessary to add the caveat that the study blocks represent only a

portion of the area surveyed during the pre-project inventory. Hence, it is likely that at

least some of the species not noted during baseline sampling may persist on other parts of

the property.

The low floristic similarity between the two HRS sites may bode well for restoration

efforts at Atwell Island. A number of the introduced species that were abundant in the

Tranquillity HRS plots and adjacent lands (e.g., Sisymbrium irio, Bromus madritensis

subsp. rubens, Beta vulgaris) were much less prevalent at the Atwell Island HRS plots.
Land Retirement Demonstration Program: Year 3

44

In contrast, Bassia hyssopifolia—a fairly noxious weedy species—was not noted for the

Tranquillity HRS plots during baseline sampling yet was fairly abundant in the Atwell

Island HRS plots (Table 9). Therefore, the impression of the Atwell Island HRS as being

fairly weed-free relative to the Tranquillity HRS is conditional. Furthermore, as has been

seen in the Tranquillity studies, a species that is initially present in low abundance can

quickly become predominant (e.g., Sisymbrium irio).

b. Invertebrate Surveys

i. Methods

A single pitfall array was established in the center of each plot. Each array consisted of

four, 3-gallon buckets connected by 20-foot sections of galvanized steel flashing (Figure

22). The buckets were sunk into the soil so that the rim of the bucket was at ground

level, with the lid of the bucket situated slightly above the rim on wooden stakes. Pitfalls

were opened the morning prior to the survey and remained open for approximately 24

hours before being checked. Pitfall array checks were conducted for 4 consecutive days

beginning just after sunrise on 12-15 June 2001. Small mammals were counted and

released from the pitfalls at the beginning of each survey. Pitfall arrays were removed

after sampling so that the barley could be harvested and the treatments applied to the

plots. Arrays will be reinstalled in 2002 prior to the first post-treatment sampling effort.
Land Retirement Demonstration Program: Year 3

45

Figure 22. Locations of pitfall arrays, sweep transects, cover boards, avian transects, and

small mammal trapping lines on an Atwell Island HRS plot.

Sweeps of vegetation were conducted to capture invertebrates occupying the upper tier of

vegetation. Vegetation sweeps were conducted on 14 and 18 June 2001. Sampling

consisted of walking a 50 m long sampling transect and sweeping vegetation with an

insect net 50 times. Transects were placed so that they intersected the pitfall arrays and

were centered in the plots (Figure 22). The same transects will be sampled in subsequent

years. Invertebrates collected from the sweeps were transferred to ZiplocTM bags, put on

ice, and, upon arrival at the lab, frozen. Invertebrates were identified to the level of

family and counted. Abundance, richness, and composition information obtained by

sweep sampling is currently being analyzed.

ii. Results

Richness among the blocks was relatively constant at 13 to 16 orders per block.

However, species composition varied tremendously (Table 20). Block 1 was dominated

by Thysanoptera (49.7%) and Orthoptera (25.81%) whereas Block 2 was dominated by
Land Retirement Demonstration Program: Year 3

46

Acari (31.25%), Thysanoptera (20.47%), Isopoda (14.56%), and Araneae (13.94%).

Block 3 was dominated by a single order, Coleoptera (76.84%).

Table 20. Composition (abundance of each taxa divided by the total abundance) of

invertebrates collected in pitfall traps in the 3 study blocks at the Atwell Island site, 2001.

Order Block 1 Block 2 Block 3

Acari 0.02 31.25 0.79

Araneae 8.04 13.94 9.34

Blattaria 0 0.09 0.01

Centipede 0 0 0.23

Coleoptera 11.94 7.45 76.84

Collembola 0.24 0.05 0

Dermaptera 0.38 0.41 0.55

Hemiptera 0.48 0.30 0.18

Homoptera 0 0.02 0.01

Hymenoptera 2.82 5.46 0.49

Isopoda 0.53 14.56 5.20

Lepidoptera 0.01 0.02 0

Mantodea 0 0 0.01

Orthoptera 25.81 4.40 1.49

Scorpiones 0.01 0.23 0.80

Solifugae 0 0.18 0.02

Thysanoptera 49.70 20.47 0.58

Thysanura 0.01 1.17 3.47

iii. Discussion

Invertebrate data were collected on the study plots during the summer when the plots

were covered in mature, dry barley. Treatments have since been installed on the plots

and we suspect invertebrate richness and abundance will increase as more natural

conditions develop on the site.

c. Amphibian and Reptile Surveys

i. Methods

Reptiles and amphibians were sampled in conjunction with the invertebrate pitfall

sampling efforts and through incidental observations by field biologists when they were

on the study site. In 2002 we will implement focused sampling for reptiles and

amphibians by walking a single transect and by checking two cover boards that will be

installed on each plot (Figure 22).
Land Retirement Demonstration Program: Year 3

47

ii. Results

No reptiles or amphibians were captured in the pitfalls and there were no incidental

sightings of reptiles or amphibians on any of the plots. Some reptiles and amphibians

were observed in the vicinity of the research blocks during site-wide surveys (see section

III B 2).

iii. Discussion

During baseline data gathering, the study plots were planted with a cover crop of barley

that was sprinkler irrigated. Prior to the barley planting, the fields were disked. These

activities and past farming operations effectively reduced the likelihood of amphibians or

reptiles being present on the study plots prior to the treatments being applied.

d. Avian Surveys

i. Methods

Bird surveys were conducted on 7-9 May, 25-27 July, and, 16-18 October, 2001 in order

to estimate richness, abundance, and use of the research blocks. Two census points and

one north-south line transect were established in each study plot (Figure 22). The line

transect traversed the space between each census point, a distance of 90m, and was

walked within a 2-3 minute time period. Census data was collected at each point for 5

minutes. Avian sampling occurred for 3 consecutive mornings each quarter.

ii. Results

A total of 14 bird species were observed on the Atwell Island study plots, but the greatest

species richness occurred on blocks 1 and 2 with 10 and 11 species, respectively (Table

21). Species richness on Block 1 was greatest in the spring whereas species richness on

Block 2 was greatest in the fall. Only four species were observed on Block 3. Redwinged blackbirds constituted the majority of sightings on all blocks, but they were only

present during the spring census when barley was present on the plots. Horned larks

were very abundant on Block 2 in the fall. Western meadowlark numbers seemed to

remain relatively constant across seasons and blocks. Savannah sparrows were only

detected on the plots during the fall census. Four bird species of special concern were

observed on the Atwell Island study blocks (Table 21), the most ubiquitous and abundant

of these was the horned lark.
Land Retirement Demonstration Program: Year 3

48

Table 21. Bird species observed and abundance (mean number observed per day) on the

3 study blocks at the Atwell Island site, 2001.

Species Status Block 1 Block 2 Block 3

Loggerhead Shrike CSC/FSC 0 0 0 0 0 0.33 0 0 0

Northern Harrier CSC 0 0 0 0 0 0.33 0 0 0

Long-billed Curlew CSC 0 0.67 0 0 0 0 0 0 0

Western Meadowlark 2.00 0.67 4.67 1.33 0.33 5.67 7.67 1.33 1.67

Western Kingbird 0.33 0 0 0 0.33 0 0 0 0

Tree Swallow 0 0 0 0 0 6.67 0 0 0

Savannah Sparrow 0 0 0.33 0 0 1.67 0 0 0

Red-winged

Blackbird 69.33 0 0 55.00 0 0107.00 0 0

Mourning Dove 0.67 0 0 0.33 0 0 0 0 0

Mallard 0 0 0 0.67 0 0 0 0 0

Cliff Swallow 0.33 0 0 0 0 0 0 0 0

1. Key to status: CSC, California species of concern; FSC, Federal special concern species.

iii. Discussion

Although the species richness and abundance of birds on the study blocks may appear to

be low, it was not surprising given the condition of the study plots. The spring census

was conducted prior to barley growth, the summer census period the barley was mature,

and during the fall census the barley had been harvested and the plots were covered in

stubble. We believe that once restoration has occurred on the plots, bird species richness

and abundance will increase.

e. Small Mammal Surveys

i. Methods

Small mammal trapping was conducted on 22-25 October, 2001 to estimate richness and

abundance. Two trap lines were established within each plot, each 40 m long and

containing 5 Sherman live traps spaced 10 m apart (Figure 22). Traps were baited with

white proso millet seed and one dry paper towel was placed in each for shredding

material. Baiting of traps began approximately 1 hour before sunset and traps were

checked approximately 2 hours after sunset. All animals captured were identified to

species, sexed, weighed, marked by clipping fur, and reproductive status determined.

ii. Results

Although a total of 1,920 trap nights were conducted during the survey, no small

mammals were captured. One pocket mouse (Perognathus inornatus) a Federal Species

of Concern, was captured by hand on 21 October in the barley buffer north of Plot 39 on

Block 3.
Land Retirement Demonstration Program: Year 3

49

iii. Discussion

The complete lack of captures suggests that there were very few small mammals on the

study plots when the blocks were planted in barley. Planting the cover crop (disking of

the field and planting and watering the barley) in combination with past farming activities

on the study blocks, likely reduced the potential for small mammals to occur.
Land Retirement Demonstration Program: Year 3

50

III. SITE-WIDE ACTIVITIES

This section describes the restoration research, biological monitoring, and management

actions that have been conducted during 2001 on the Tranquillity and Atwell Island study

sites. Included are results and updates from restoration trials that were implemented in

past years and descriptions of trials that were implemented in 2001.

A. Tranquillity

1. Restoration Studies

Locations of the various restoration study areas at the Tranquillity site are presented in

Figure 23.

Figure 23. Locations of the various restoration study areas at the Tranquillity site.
Land Retirement Demonstration Program: Year 3

51

a. Imprinting vs. Drilling of Native Seeds

In this and the following trial (imprinting vs. drilling of cover crops), methods to

introduce native seeds without the expensive ground preparation often required with

traditional seed drills were explored. Tillage brings weed seed to the soil surface and

breaks down soil structure. Hence, it was anticipated that less soil disturbance would

decrease weed density and promote the establishment of mycorrhizal networks in the soil,

both of which tend to favor native plants (St. John 1995).

i. Methods

The performance of two seeding techniques, imprinting and drilling, was investigated

(see Uptain et al., 2000 for a detailed description of these techniques). Installation of the

experiment was undertaken in the fall of 2000. Six experimental plots approximately 1.5

acre in size were installed; three plots were imprinted and three were drilled with native

seed (Figure 24). The seed mixture contained seeds of nine native species (Table 22).

Vegetation sampling was conducted the following spring (May 15, 2001). Vegetation

sampling was accomplished by taking eight samples (35 x 70 cm) per plot. Estimates of

plant species cover and composition were obtained by the methodology described for the

permanent study plots.
Land Retirement Demonstration Program: Year 3

52

Figure 24. Location of the Imprinting vs. drilling of native seed trial, and the Imprinting

vs. drilling of cover crops trial.

ii. Results

Five of the nine species included in the seed mix were encountered during sampling; all

five were present in both the imprinted and drilled plots (Table 22). Lasthenia

californica was the most abundant imprinted species (Figure 25 A); however, this species

was much less successfully established through drilling (Figure 25 B). In general, the

abundance of the remaining successfully seeded species (i.e., those that were encountered

during sampling) varied little between seeding techniques (Table 22; Figure 25). An

exception was Amsinckia menziesii, which appeared to be more successfully established

by drilling than by imprinting.
Land Retirement Demonstration Program: Year 3

53

Table 22. Overview of species encountered in imprinting vs. drilling of native seed.

Species marked with an asterisk are those used in the seed mix. Species with no percent

cover are those that were included in the seed mix but which were not encountered during

sampling. Note: species are listed in descending order of performance in both trials (i.e.,

the sum of total mean percent covers from both the imprinted and drilled treatments).

Scientific name Taxon code1 Origin Imprinted2 Drilled3

Melilotus indica MEIN Introduced 38.42 43.56

Sisymbrium irio SIIR Introduced 26.69 27.83

Lasthenia californica* LACA Native 3.47 0.03

Hordeum murinum HOMU Introduced 1.69 0.56

Hordeum depressum* HODE Native 1.42 0.53

Capsella bursa-pastoris CABU Introduced 0.97 0.97

Vulpia microstachys* VUMI Native 1.03 0.61

Atriplex argentea ATAR Native 0.44 0.36

Amsinckia menziesii* AMME Native 0.08 0.58

Leymus triticoides* LETR Native 0.19 0.44

Phalaris sp. PHSP Not known 0.42 ----

Hordeum vulgare HOVU Introduced ---- 0.17

Bromus madritensis BRMA Introduced ---- 0.17

Salsola tragus SATR Introduced 0.17 ----

Atriplex sp. ATSP Not known ---- 0.03

Atriplex polycarpa* ---- Native ---- ----

Isocoma acradenia* ---- Native ---- ----

Sporobolus airoides* ---- Native ---- ----

Suaeda moquinii* ---- Native ---- ----

1. As referred to in Figure 25.

2. Mean percent cover in samples taken in the imprinted plots.

3. Mean percent cover in samples taken in the drilled plots.
Land Retirement Demonstration Program: Year 3

54

Figure 25. Rank-abundance of species encountered in the imprinted plots (A) and drilled

plots (B). A key to species is provided in Table 22.
Land Retirement Demonstration Program: Year 3

55

In order to compare the results statistically, the data were arcsine transformed and a t-test

conducted. The difference between the two treatments was not found to be statistically

significant when considering all seeded species; the sole species in which there was a

significant difference between treatments was Lasthenia californica (P = 0.0167).

The mean percent cover of the target species seeded by imprinting was nearly three times

the value for drilling (Table 23). Nevertheless, non-planted species were by far the most

abundant component of the vegetation (Figure 25). The dominance of "non-planted

species" is clear when the data is tabulated by species "class" (Table 23); for both

treatments, the mean percent cover contributed by introduced species was more than an

order of magnitude greater than that of the seeded species.

Table 23. Summary of species encountered in imprinting vs. drilling of native seed trial.

Species class Imprinted1 Drilled2

Planted 6.194 2.194

Not planted 68.389 73.444

Not known* 0.417 0.028

1. Mean percent cover of species in the imprinted plots.

2. Mean percent cover in the drilled plots.

* Species that were only partially identified.

iii. Discussion

Of particular note were the different results obtained by imprinting and drilling Lasthenia

californica. This species has been one of the more successful in the restoration mix and

the difference between the two techniques suggests that it would be inefficient to attempt

to establish this species by range-drilling. In contrast, Amsinckia menziesii appeared to

be more successfully introduced when drilled; but the results were not statistically

significant. Nevertheless, A. menziesii is now being considered for inclusion in future

restoration efforts. We need to decide if this species should be seeded by some method

other than imprinting (e.g., broadcasting following the imprinting of the other species).

Three of the species that were included in the seed mix, but which weren't encountered

during sampling—Atriplex polycarpa, Isocoma acradenia, and Sporobolus airoides—

also had fairly limited success in the permanent plots. Their seeming inability to become

established through either of the seeding methods used here suggests that their inclusion

in the seed mixes for future restoration efforts may not be appropriate. These species

might still be successfully introduced into restored lands by broadcasting or as

transplanted seedlings. These species might also demonstrate better success when drilled

or imprinted on different soil types. Additionally, it may well be that their success will

be limited to years with additional rainfall or with a different temporal distribution of

rainfall.
Land Retirement Demonstration Program: Year 3

56

Of overriding importance is the very low percent cover of the seeded species relative to

non-planted species (Table 23). It seems likely, given the conditions at the Tranquillity

site, that neither imprinting nor drilling will be sufficient to assure the establishment of

native vegetation without some form of weed control.

b. Imprinting vs. Drilling of Cover Crops

It may often be necessary to accomplish large-scale restoration in phases. Cover crops

will most likely be an important restoration tool in these situations, particularly if they

can be planted with minimum ground preparation (see Uptain et al. 2000 for an

elaboration of the potential benefits associated with cover cropping).

i. Methods

As in the preceding trial, the performance of two seeding techniques, imprinting and

drilling was investigated. Comparisons were investigated using two seeding regimes: 1)

a barley monoculture; and, 2) barley mixed with three native grasses (Bromus carinatus,

Leymus triticoides, Vulpia microstachys). Installation of the experiment was undertaken

in the fall of 2000. Three replicates of each treatment were installed on 12 experimental

plots, each approximately 1.5 acre in size (Figure 24). Vegetation sampling was

conducted the following spring (14-15 May 2001). Eight samples (35 x 70 cm) per plot

were taken. Estimates of species cover and composition were obtained using the

methodology described for the permanent study plots.

ii. Results

Barley

Barley was by far the most abundant species in both the imprinted and drilled treatments

(Table 24). Although a few non-seeded species were present in the study plots, these

contributed little to the overall vegetative cover (Table 24; Table 25; Figure 26 A and B).

All non-seeded species encountered in the plots were non-natives (Table 24). Barley was

not established better by imprinting than by drilling (Table 25).

Based on the tabulated data, it appeared that barley was more successfully established by

imprinting than by drilling (Table 25). However, in a t-test of the arcsine transformed

data the difference between the two treatments was not found to be statistically

significant (t= 1.051 ; p= 0.3522).

Barley and native species

Barley was by far the most abundant species in both the imprinted and drilled treatments

(Table 24). Of the remaining three seeded species, two were encountered in both the

imprinted and drilled plots, while the fourth (Bromus carinatus) was not recorder for

either seeding method (Table 24). More non-seeded species (seven, Table 24) were

encountered in this trial than were encountered in the preceding trial (i.e., imprinting vs.

drilling of barley). Non-seeded species were of both native and non-native origin (as

well as two species of unknown origin). Non-seeded species comprised a greater

percentage of total vegetation cover than in the preceding trial (Table 25; Figure 26 C and
Land Retirement Demonstration Program: Year 3

57

D). Drilling yielded a somewhat greater mean percent cover of seeded species than did

imprinting (Table 25). Nevertheless, a t-test of the arcsine transformed data indicated

that differences between the treatments were not significant (t = 1.052; p = 0.35).

Likewise, no significant differences between treatments were found for any individual

species.

From an examination of the data compiled by species "class" (i.e., cover crop vs. nonplanted species), it appeared that seeding barley alone was more effective at excluding

introduced species than was the mixture of barley and native grass species (Table 25). A

t-test of the arcsine transformed data indicated that this perceived difference was not

statistically significant (t = -4.07544; p = 0.002). However, it is suspected some of the

difference between the treatments was due to weedy species may have been introduced

with the native grass seed.

Table 24. Overview of species encountered in imprinting vs. drilling of cover crops.

Species marked with an asterisk are those used in the seed mix. Species with no percent

cover are those that were included in the seed mix but which were not encountered during

sampling. Note: species are listed in descending order of total mean percent cover (i.e.,

the sum of all treatments).

Species Origin

Barley

Imprinted1

Barley

Drilled2

Barley and

natives

Imprinted1

Barley and

natives

Drilled2

Hordeum vulgare* Cultivar 67.78 55.83 49.58 51.67

Melilotus indica Introduced 2.39 1.42 8.92 3.42

Sisymbrium irio Introduced 1.19 0.08 1.22 1.19

Vulpia microstachys* Native -- -- 1.03 1.25

Leymus triticoides* Native -- -- 0.86 0.58

Grass A Not known -- -- 0.31 0.44

Capsella bursa-pastoris Introduced -- 0.22 0.33 0.19

Grass B Not known -- -- 0.06 0.19

Avena fatua Introduced -- -- 0.03 0.17

Brassica nigra Introduced -- -- 0.17 0.00

Hordeum murinum Introduced 0.06 -- 0.06 0.03

Atriplex argentea Native -- -- -- 0.06

Amsinckia menziesii Native -- -- 0.03 --

Phalaris sp. Not known -- -- -- 0.03

Bromus carinatus* Native -- -- -- --

1. Mean percent cover in samples taken in the imprinted plots.

2. Mean percent cover in samples taken in the drilled plots.
Land Retirement Demonstration Program: Year 3

58

Table 25. Summary of species classes encountered in imprinting vs. drilling of cover

crops.

Species class

Barley

Imprinted1 Barley Drilled2

Barley and

natives

Imprinted1

Barley and

natives Drilled2

Cover crop 67.78 55.83 51.47 53.50

Non-planted 3.64 1.72 11.11 5.72

1. Mean percent cover in samples taken in the imprinted plots.

2. Mean percent cover in samples taken in the drilled plots.

Figure 26. Rank abundance of species encountered in imprinting and drilling of cover

crops: a and b (barley only), and c and d. (barley with native grasses).

iii. Discussion

The absence of statistically significant differences between imprinting and drilling of

barley suggests that either approach was of approximately equal applicability, at least

within the context of the set of conditions at the site.

Of particular interest was the difference in the number of introduced species in the two

trials (Table 24). While some of these differences can undoubtedly be ascribed to
Land Retirement Demonstration Program: Year 3

59

sampling artifacts, the results suggest that weedy species are being introduced to the site

by their inclusion in commercially purchased native seed.

The extremely poor response of Bromus carinatus to both seeding methods is very

interesting. This species responded fairly well to imprinting in the Tranquillity HRS

plots (i.e., present in about 25% of the quadrats in imprinted plots). However, in this

years vegetation sampling it was noted in only two quadrats. This decline in frequency,

along with the poor performance of B. carinatus in the seeding trial, may indicate that the

dry conditions that were characteristic of 2001 may have been unsuitable for the

germination and growth of this species. It should also be noted that as many of the

grasses present in the plots were too young to be confidently identified, the performance

of some species may have been better than indicated by the data.

c. Section 23 Restoration

i. Methods

The 160 acres at the Tranquillity site comprising the northwest quadrant of Section 23

were restored commencing in December. Seventeen species were imprinted from seed

(Table 26, Uptain et al. 2001). Additionally, 5,500 seedlings of three species (Allenrolfea

occidentalis, Atriplex polycarpa, and Sporobolus airoides) were planted at the site.

Vegetation sampling was undertaken in May, 2001. The 160-acre area was divided into

two halves, with 24 vegetation samples (35 cm by 70 cm rectangular quadrats) taken

from each area. All species were noted, and the percent cover was estimated for each

species using a modified Daubenmire cover scale (Bonham 1989). Total percent cover of

all species within the quadrat was estimated using the same cover scale. Whenever

possible, species were identified completely; failing this, species were assigned morphospecies names.

ii. Results

Eighteen taxa were encountered during vegetation sampling (Table 26). Of these, seven

were native, seven were clearly introduced, one (barley) was a non-native species that

had been planted the year before, and three species could not be definitely assigned as to

origin (Table 26). Of the seven native species, five had been imprinted; thus, of the

seventeen species imprinted in the restoration area, only about one quarter (29.1%) were

noted during vegetation sampling.
Land Retirement Demonstration Program: Year 3

60

Table 26. Overview of species encountered during vegetation sampling of the 160-acre

restoration area for 2001 (Section 23, Tranquillity site). Species marked with an asterisk

are those used in the seed mix.

Species Common name Freq.1 Cover2 Site cover3 Origin4

Phalaris sp. canarygrass 43 10.95 9.81 N.A.

Brassica nigra black mustard 40 20.43 17.02 I

Avena fatua wild oats 37 16.61 12.80 I

Amsinckia menziesii* farmer's fireweed 25 2.98 1.55 N

Lasthenia californica* goldfields 17 1.09 0.39 N

Beta vulgaris common beet 13 12.62 3.42 I

Hordeum vulgare Barley 11 3.41 0.78 B

Melilotus indica sourclover 11 4.73 1.08 I

Phacelia distans common phacelia 10 2.70 0.56 N

Sisymbrium irio London rocket 6 0.50 0.06 I

Hordeum murinum foxtail Barley 5 1.00 0.10 I

Vulpia microstachys* small fescue 5 1.00 0.10 N

Gilia tricolor* bird's eye Gilia 3 1.33 0.08 N

Atriplex argentea silver scale 2 1.75 0.07 N

Hordeum depressum alkali Barley 2 0.50 0.02 N

Erodium cicutarium red-stemmed filaree 1 0.50 0.01 I

Unknown Atriplex saltbush 1 0.50 0.01 N.A.

Unknown N.A. 1 0.50 0.01 N.A.

As with the Tranquillity HRS plots, the most frequently encountered species at the 160-

acre restoration site were non-imprinted. The most frequently encountered species

(Phalaris sp.; Table 26) was not identifiable to species and, as both native and non-native

representatives of the genus are known for California, it was not possible to identify its

origin. Still, no species of the genus were included in the restoration mix and the only

species of Phalaris noted to date at the Tranquillity site has been P. minor (an introduced

species). It seems likely that this was also the species collected during sampling at the

160-acre restoration site. Overall, six species occurred in at least 25% of the sampling

quadrats (Table 26); of these, only two —Amsinckia menziesii and Lasthenia

californica—were imprinted.

In order to ascertain the relative success of the planted species, the cover data were

tabulated by class (i.e., planted, non-planted, etc.). By all measures, non-planted species

far exceeded the contribution of imprinted species (Table 27). In order to better consider

the contribution of particular species and species classes to the restored vegetation, a

rank-abundance curve was plotted from the sampling data (Figure 27). The general

predominance of non-imprinted species is clearly evident, as the four most abundant

species were either introduced or, in the case of the aforementioned Phalaris sp., of
Land Retirement Demonstration Program: Year 3

61

uncertain status. Nevertheless, the gradual slope of the curve suggests relatively high

evenness in the first year's vegetation (sensu Kent and Coker 1992).

Figure 27. Rank-abundance of species encountered during vegetation sampling of the

Section 23 restoration.

Table 27. Summary of species classes encountered during vegetation sampling of the

Section 23 restoration.

Species class Freq.1 Cover2 Site cover3

Planted 50 6.40 2.13

Non-planted 127 61.33 35.16

Cover Crop 11 3.41 0.781

N.A. 45 11.95 9.83

1. Frequency: the number of quadrats in which the taxon was noted.

2. Estimated mean percent cover of the taxon calculated from only those quadrats in which the species was noted.

Percent cover values were estimated from midpoints of the cover class (e.g., a species with an estimated cover

of 5-25% was evaluated as having a cover of 15%).

3. Estimated site-wide mean percent cover calculated from the summed cover data divided by total (48) of

quadrats.
Land Retirement Demonstration Program: Year 3

62

iii. Discussion

Although many native species were noted in the restored area, introduced taxa were far

more abundant (Table 26; Table 27). The preponderance of a number of aggressively

weedy species, such as Brassica nigra, Beta vulgaris, Sisymbrium irio, and Atriplex

argentea, will make it difficult for native species to gain dominance. The restoration

study on this area was compromised when the area was mistakenly grazed by sheep in

late September-early October. By the time the sheep were removed from the study site,

virtually all the transplanted perennial species that had become established were grazed to

ground level. We do not know the effects on the seed bank but anticipate that the grazing

will favor the weedy species.

Of the four imprinted species that were noted during sampling, two—Lasthenia

californica and Vulpia microstachys—also were present in the seed mix used in

establishing the Tranquillity HRS plots. The establishment of both species was fairly

successful in the plots during the first year, and their performance in the 160-acre

restoration area suggests that their continued inclusion in the restoration mix is

warranted. The successful establishment of Amsinckia menziesii (i.e., the fourth most

abundant species, Figure 27) from imprinted seed also is noteworthy. A. menziesii

appears to be capable of competing against non-native weeds. Its use in future

restoration mixes should be considered. Nevertheless, A. menziesii was much more

successfully seeded by drilling than by imprinting (see section III A 1 a) and initial

indications from the Native Plant Nursery suggest that this species may be successfully

established by broadcasting. Hence, it may be optimal to introduce A. menziesii by

broadcasting after other species have been imprinted. Also of note was the fairly

successful establishment of another native species, Phacelia distans, the eighth most

abundant species (Figure 27). Although not included in the seed mix, P. distans is

common in some areas adjacent to the Tranquillity site and its use in further restoration

activities should be considered.

d. Hedgerow Seeding

Vegetation on field borders may harbor pests, therefore these areas are usually disked or

sprayed with herbicide. Hedgerows of native species situated along field borders may be

an alternative to disking or herbicide use. Hedgerows may be maintained with minimal

management, may tend to favor beneficial insects, and also can provide important habitat

for birds and other wildlife (Clark and Rollins 1996).

An approximately 10-foot wide hedgerow situated along the southern and eastern edge of

the ancillary trial area (Figure 23) was imprinted with native seeds in December 2000

(Table 28). Berms were constructed along the edges of the hedgerow to allow the area to

be flood irrigated. In January 2001, seedlings of Atriplex lentiformis, Leymus triticoides,

Nassella pulchra and Sporobolus airoides were planted along the berm adjacent to the

hedgerow.
Land Retirement Demonstration Program: Year 3

63

Table 28. Seed mix and application rate for the hedgerow seeding at the Tranquillity

site. Seed source information provided by seed vendor.

Scientific name Common name Seed source Lbs./acre

Amsinckia menziesii rancher's fireweed San Bernardino 3

Atriplex lentiformis quailbush Taft 3

Atriplex polycarpa valley saltbush Fresno County 5

Dichelostemma capitatum blue dick Camp Pendleton 3

Eremocarpus setigerus doveweed Kern County 3

Frankenia salina alkali heath Southern CA 8

Helianthus annuus sunflower Ensenada 8

Heliotropium curassavicum heliotrope Temecula 3

Leymus triticoides creeping wild rye Fresno County 8

Sporobolus airoides alkali sacaton Unknown 3

Vulpia microstachys Nuttall's fescue Fresno County 8

Vegetation monitoring was limited to periodically recording observations throughout the

year. Atriplex lentiformis was observed to do well in 2001. Helianthus annuus

germinated well in this habitat and set fruit. However, H. annuus is an annual species

and it still remains to be seen whether or not it will prove capable of re-seeding itself as

disturbance in this area is lessened. Leymus triticoides also grew well in this area.

Periodic monitoring will continue in 2002.

e. Marsh Area Seeding

Historically, a seasonal wetland was formed by agricultural runoff from lands adjacent to

LRDP lands. This water would often overflow into LRDP property, forming a marshy

area on the order of 8 acres. In 2000 this area was imprinted with a native seed mix of 14

species. Regrettably, later in the year this area was inadvertently disked. Although

formal sampling could not be conducted, individuals of four of the imprinted species

(Frankenia salina, Lasthenia californica, Heliotropium curassavicum, and Suaeda

moquinii) were observed along the fringes of the disked area. Additionally, some sterile

grasses were observed growing in the same area, but these could not be confidently

identified.

In January 2002, a 9.6-acre area was re-imprinted using the same seed mix as was used in

2000 (Table 29). Currently, LRDP controls the flow of water to the canal that formerly

provided the runoff water, and the marshy area now receives significantly less water than

in previous years. Hence, species that naturally occur in both mesic conditions and in

upland habitats were selected for the seed mix. To monitor the success of the trial,

vegetation sampling will be conducted in spring, 2002.
Land Retirement Demonstration Program: Year 3

64

Table 29. Species seeded in the marsh area at the Tranquillity site, 2002.

Scientific name Common name Lbs./acre

Atriplex polycarpa valley saltbush 0.10

Dichelostemma capitatum blue dick 0.63

Eleocharis macrostachya spikerush 0.10

Frankenia salina alkali heath 0.31

Heliotropium curassavicum heliotrope 0.31

Isocoma acradenia goldenbush 0.21

Juncus balticus Baltic rush 0.21

Lasthenia californica goldfields 0.42

Leymus triticoides creeping wild rye 1.67

Lupinus bicolor miniature lupine 0.10

Mimulus guttatus monkeyflower 0.21

Poa secunda bluegrass 0.10

Sporobolus airoides alkali sacaton 0.83

Suaeda moquinii bush seepweed 0.21

f. Ditch Bank Seeding and Planting

Ditches are a common feature of the agricultural landscape and are often managed with

herbicides and blading to prevent the accumulation of weedy species. Native plants may

prevent weedy species from overtaking ditches while providing excellent cover for

wildlife.

A ditch was created on the northern and western boundary of the Section 23 restoration

area (Figure 23). Seedlings of Leymus triticoides and Nassella pulchra were planted

along the ditch banks in December, 2000. In January, 2001 the ditch was seeded by hand

with a mix of species that would typically do well along an irrigation ditch (Table 30).

The ditch was flood irrigated shortly after seeding and was not watered again.
Land Retirement Demonstration Program: Year 3

65

Table 30. Seed mix and application rate for ditch bank seeding at the Tranquillity site.

Seed source information provided by seed vendor.

Scientific name Common name Seed source Lbs./acre

Amsinckia menziesii fiddleneck San Bernardino 12.5

Cressa truxillensis alkali weed Camp Pendleton 8.0

Eleocharis macrostachya spikerush Grass Valley 4.2

Frankenia salina alkali heath San Diego County-Coast 8.0

Helianthus annuus sunflower Ensenada 8.0

Heliotropium curassavicum heliotrope Temecula 17.0

Hordeum depressum low Barley Riverside 21.0

Leymus triticoides creeping wild rye Fresno County 21.0

Malvella leprosa alkali -mallow Unknown 8.0

Nassella pulchra purple needle grass Central Valley 12.5

Poa secunda bluegrass West Lower Central Valley 42.0

Sporobolus airoides alkali sacaton Unknown 12.5

Vulpia microstachys Nuttall's fescue Fresno County 21.0

Vegetation monitoring was limited to periodically recording observations throughout the

year. From these observations, it appeared that both Leymus triticoides and Nassella

pulchra had become successfully established. Nevertheless, it remains to be seen

whether or not the majority of these individuals will survive the dry season. Periodic

monitoring will continue in 2002.

g. Native Plant Nursery

Because of the need to maintain local genotypes, seeds collected from local sources are

preferable to commercially obtained seeds. A potentially serious problem exists when

seeds or plants of different genotypes are introduced. In this manner, genetic mixing of

populations adapted to different regions can occur. The introduction of non-local

genotypes can produce individuals that competitively displace the local variety, or which

respond to environmental cues differently than locally adapted plants. Hence, it is very

important to use local seed stock to the maximum extent when implementing restoration

projects.

Locating sufficient sources of native seed of local genotype has proven extremely

problematic. Remnant native seed banks in the Central Valley, such as in ecological

reserves and wildlife preserves, are rare and are generally quite limited in size.
Land Retirement Demonstration Program: Year 3

66

Furthermore, commercial suppliers of native seed often have limited supplies, are costly,

and offer seed collected from geographically disjunct locations. In order to circumvent

these limitations, the establishment of a Native Plant Nursery was begun in 2001 at the

Tranquillity site.

Seeds from selected native species were collected during the 2001 growing season.

Permission and any required permits were obtained from private landowners and

government agencies. In order to minimize the mixing of local with non-local genotypes,

collections were undertaken in as close a proximity to the Tranquillity site as possible.

The health of the population was assessed prior to collection. No more than 5% of a

population’s seeds was harvested, and diseased or damaged plants were excluded from

collection. Seed collections made during 2001 are listed in Table 31. With the exception

of one location (Fancher and Belmont; Figure 28), all seed was collected from within 15

miles of the Tranquillity site.

Table 31. Dates, species collected, and locations of 2001 native seed collections.

Date Species collected Location

Phacelia distans Westlands property

Castilleja exserta Fancher and Belmont

Lasthenia chrysantha

1 May 2001

Castilleja exserta

Fresno West Golf and CC

25 June 2001 Hemizonia pungens Kerman ecological reserve, North

26 June 2001 Hemizonia pungens Kerman ecological reserve, South

Hemizonia pungens Lanfranco property 16 July 2001

Asclepias fascicularis Kerman ecological reserve, South

17 July 2001 Hemizonia pungens

Asclepias fascicularis

24 July 2001

Hemizonia pungens

Suaeda moquinii

7 September 2001

Hemizonia pungens

Kerman ecological reserve, North

Sporobolus airoides

Frankenia salina

Alkali Sink ecological reserve

Suaeda moquinii

Frankenia salina

28 September 2001

Atriplex polycarpa

Kerman ecological reserve, North

8 October 2001 Isocoma acradenia Kerman ecological reserve, South
Land Retirement Demonstration Program: Year 3

67

Figure 28. Locations of native plant seed collection sites near the Tranquillity site.

The timing of seed collection is critical, and the extremely variable springtime

temperatures and rainfall patterns in the San Joaquin Valley confound scheduling. Time

of collection is particularly critical for short-lived annual species. Seed collecting usually

begins in the spring and lasts through late fall. Species in the genera Lasthenia,

Castilleja, and Dichelostemma tend to reach maturity by early spring; hence, seed

collecting can commence as early as late March or April. Late blooming shrubs such as

Atriplex spp., Isocoma acradenia, and Allenrolfea occidentalis generally do not produce

mature fruits until late summer or early fall, thereby extending collecting into November.

Due to an unusually warm and early spring in 2001, the collection window for many of

the showy annuals was shortened. Thus, little seed was harvested from species such as

Lasthenia chrysantha, Castilleja exserta, and Phacelia distans. Nevertheless, a long

summer and mild fall allowed for an ample collection of Isocoma acradenia, and

Hemizonia pungens.

Harvested seed was stored in paper bags, labeled with identifying codes (species, seedlot, etc.), and dried in a seed dryer at the ESRP lab. In some cases, seed was processed to

remove chaff and foreign matter. This process proved to be sufficiently difficult and

time-consuming so as to preclude its general application. Additional seed was available

from seed collections undertaken in 2000 (see Uptain et al, 2001), and we plan to plant

these seeds in the Nursery. A complete list of the species available for planting is

presented in Table 32.
Land Retirement Demonstration Program: Year 3

68

Table 32. Native plants seed available for planting in the native seed nursery at the

Tranquillity site. Species marked with an asterisk are those also used in the restoration

seed mix.

Family Binomial Common name Life-history

Asclepiadaceae Asclepias fascicularis narrow-leaved milkweed perennial herb

Asteraceae Helianthus annuus sunflower annual herb

Asteraceae Hemizonia pungens* spikeweed annual herb

Asteraceae Isocoma acradenia* goldenbush shrub

Asteraceae Lasthenia chrysantha alkali goldfields annual herb

Boraginaceae Amsinckia menziesii farmer's fireweed annual herb

Capparaceae Wislizenia refracta jackass clover annual herb

Caryophyllaceae Spergularia macrotheca Sand Spurrey perennial herb

Chenopodiaceae Atriplex polycarpa* valley saltbush shrub

Chenopodiaceae Suaeda moquinii* bush seepweed perennial herb

Euphorbiaceae Eremocarpus setigerus doveweed annual herb

Frankeniaceae Frankenia salina* alkali heath perennial herb

Hydrophyllaceae Phacelia distans common phacelia annual herb

Lamiaceae Trichostema lanceolatum vinegarweed annual herb

Liliaceae Dichelostemma capitatum blue dicks perennial herb

Poaceae Sporobolus airoides* alkali sacaton perennial herb

Scrophulariaceae Castilleja exserta purple owl's clover annual herb

* Species marked with an asterisk are those also used in the restoration seed mix.

The nursery area was disked, bermed, furrowed, and culti-packed in November, 2001.

Berms were flat-topped and were sufficiently wide so as to provide space for a number of

individuals. The nursery was designed to accommodate flood irrigation, as needed. Ten

acres have been set aside for the nursery (see Figure 23); however, it is anticipated that

only 3 acres will be used in 2002. As our stock of native seed is augmented from seed

produced in the nursery and from continued collection from native populations we expect

that larger areas will be put into production in subsequent years.

Some areas adjacent to the nursery site support large populations of two apparently

aggressively weedy species: Sisymbrium irio, and an unidentified trifoliate species

(possibly Medicago polymorpha). It seems clear that vigilant weeding, watering, and

maintenance will be necessary to ensure the successful propagation and establishment of

the native species. Additionally, we are considering the use of herbicides to prepare the

seed bed for the fall seeding effort in 2002.

h. Atriplex spinifera Planting

One priority of our restoration research has been the development of strategies for

introducing native vegetation into Bromus madritensis subsp. rubens (red brome)

dominated habitats. B. madritensis characteristically forms a heavy thatch, which inhibits
Land Retirement Demonstration Program: Year 3

69

the establishment of native vegetation and negatively impacts many terrestrial

vertebrates, especially small mammals and lizards. Atriplex spinifera (spiny saltbush), a

shrub in the Chenopodiaceae (goosefoot family), is an important component of the Valley

Saltbush Scrub community, as it provides cover and forage for a variety of wildlife

species. Additionally, A. spinifera represents the only species of native shrub that has

managed to become established on the fallow land of Section 10 ("the Donahoe") of the

Tranquillity site, an area characterized by a non-native grassland dominated by B.

madritensis.

Although mature A. spinifera shrubs grow on the Donahoe, no seedlings have been

identified during the three years we have studied the area. And, although A. spinifera

seed has been included in the seed mix used in various restoration activities at both the

Tranquillity and Atwell Island habitat restoration study sites, there has been little

indication that this species can be successfully introduced by imprinting. Likewise,

attempts at germinating seeds in nursery trials have met with little success.

In an attempt to investigate other means of establishing A. spinifera on restored land, we

contracted with Ray Leclerc, owner of the Intermountain Nursery in Auberry (Fresno

Co., California), to propagate A. spinifera from cuttings taken from existing shrubs on the

Donahoe. To maximize the number of individuals produced from the original cuttings,

these were rooted and then maintained as stock plants. Once a viable group of stock

plants was established, cuttings were taken from these plants and used to grow out more

plants. In this manner, more than 600 plants of different cohorts (i.e., age classes) were

grown for transplanting to the Donahoe. Plants were maintained in approximately

gallon-sized peat pots until transplanting, and were watered as deemed appropriate

(approximately bi-weekly) while in the nursery.

To give us a better understanding of the species' requirements, shrubs were transplanted

in groups (shrub islands) with four different configurations: 1) 10 individuals with 10-ft

spacing between plants; 2) 10 individuals with 5-ft spacing; 3) 5 individuals with 10-ft

spacing; and, 4) 5 individuals with 5-ft spacing. All individuals were characterized as

belonging to two age classes, "old plants" and "young plants". Individuals in the oldest

cohort were easily distinguished from all younger plants. Cuttings for the older plants

had been rooted before the summer of 2001, such that their foliage had developed the

summer-dormant appearance of spiny saltbush. Their stems were woody, their leaves

small and gray-green, and their root systems were developed enough to hold soil for

transplanting. Although a number of cohorts comprised the young-plants age class,

identifying characteristics were not sufficiently differentiated to allow a finer resolution.

Leaves that were larger, fleshier, and greener distinguished all of these younger plants,

which had been rooted during the summer of 2001. These plants had less root mass than

the older plants; hence, it was necessary to leave some of the youngest plants in their pots

when transplanted. In these cases, pots were slashed vertically at three or four locations

and the pot bottom was removed. In general, shrub islands were planted with individuals

from a single age class; any departures from this were noted and mapped. Shrub islands

were spaced approximately 100 ft apart along the east side of the San Luis Drain, and

along the west side of the Lateral 7 Inlet Canal (Figure 23)
Land Retirement Demonstration Program: Year 3

70

Transplanting was conducted November 14-29 2001. Most plants were removed from

the peat pots and placed in the soil up to the plants' potting soil level. A well was created

around each plant in order to concentrate water around the plant. Plants, which were left

in their pots when transplanted also, were buried to the level of the potting soil. The

upper lips of the pots served as wells with which to collect water. All plants were

watered when planted. Subsequently, plants were watered on a weekly basis until the site

received soil-soaking rains in late December. Survivorship of the plants will be

monitored periodically throughout the 2002 growing season.

i. Future Directions

i. 80-acre restoration—calibration trial

As part of the restoration activities in 2002, an 80-acre block located south of Manning

Ave (Figure 23) will be restored using the same seed mixture as was used for the HRS

plots. To better control seed application in future restoration efforts, the Manning

Avenue restoration effort will be used to refine imprinter calibration.

Our imprinter was custom made and was not calibrated by the shop that fabricated it. To

date, we have data from the imprinting of both the Atwell Island HRS plot installation

(setting 20 = 25 lbs/acre) and the USBLM's restoration activities at Atwell Island (setting

30; = 33.2 lbs/acre). The 80-acre parcel will be divided into four equal-sized areas and

each area will be seeded with the imprinter set at a different setting (imprinter settings:

15, 25, 35, 45). Data from this trial will be compared with data from the two restoration

experiments at Atwell. The amount of seed used in imprinting will be plotted against

imprinter settings, and a linear regression will be calculated for the data.

ii. Succession trial

In this trial, two factors will be examined: 1) the ability of native grasses to become

established when imprinted over an existing barley crop; and, 2) the relative abilities of

barley and imprinted native grasses to spread beyond the confines of their seeded area.

Since the inception of the habitat restoration study, barley (Hordeum vulgare) has been

used as a cover crop, to control weeds and prevent soil erosion (Selmon et al, 2000).

Although this species has demonstrated some utility, at times its establishment has

proven costly and somewhat problematic. Additionally, although the seed purchased for

these studies was ostensibly of sterile barley, it has proven capable of re-seeding itself in

the highly motile (i.e., shrinking, swelling, and cracking) soils at the Tranquillity site.

To date, areas cover-cropped with barley have generally been disked prior to imprinting.

Although this strategy has been fairly successful in removing the greatest portion of the

barley, disking represents an additional disturbance to the soil and may favor the

establishment of weeds. An alternative approach to disking is imprinting seed directly

over the cover crop. However, questions remain as to whether or not imprinted species

will, 1) be able to become established; and, 2) be able to resist incursions by adjacent

vegetation. In this trial we attempt to address these questions by monitoring temporal
Land Retirement Demonstration Program: Year 3

71

changes in strips of land planted with barley with those planted with native grasses

(Bromus carinatus, Hordeum depressum, Leymus triticoides, and Vulpia microstachys).

The trial will occupy 80 acres to the north of the berm-trial area and south of the marshmix planting area (see Figure 23). Installation will commence in February, 2002. A

stratified random blocking design will be used, with the area divided into 5 blocks. Each

block will be divided into 3 strips; each strip will contain either: 1) barley (existing); 2)

the native grass mix imprinted over existing barely; or, 3) the standard (for our HRS

studies) 13 species restoration mix imprinted over disked ground. Seeding order will be

determined randomly. The trial will be monitored periodically; if species establishment

is successful, quantitative sampling will be conducted near the end of the growing season.

iii. Berm/mycorrhizal trial

This trial was designed to examine the effects of two factors: berm "architecture" and

mycorrhizal inoculation. Observations at the Tranquillity HRS plots have led us to

hypothesize that the establishment of micro-topography on the plots (in this case, through

the construction of earthen berms) aids in the establishment of vegetation after

imprinting, and may also benefit wildlife. Previously, uniform berms were installed to

minimize sampling bias. Berms were compacted and rebuilt so that compaction by the

imprinter would not substantially reduce the final height of the berms compared with

berms that were not imprinted. This approach to berm construction required a substantial

amount of time and labor. It may be more desirable to maximize the amount of bermed

habitat in a restoration area by creating more (less "perfect") berms in the same amount of

time. This aspect of the trial will test whether it is better to make two passes (thus,

compacting the berm), or if simply making a quick berm with only one pass works just as

well for facilitating native plant germination and survival.

The Tranquillity site has been in agricultural production for decades. Agricultural

activities (primarily scraping and disking) can eliminate beneficial mycorrhizal fungi in

the soil. Mycorrhizae—the symbiosis between a plants roots and beneficial soil fungi—

aid in nutrient uptake in almost all species of plants. Half of the plots will be inoculated

with commercial mycorrhizal fungi obtained from ConservaSeed. The mycorrhizal fungi

will be applied by mixing it with the seed mix prior to imprinting the plots. Application

rate will be ca. 60lbs/acre. Particular attention will be given to species that are

mycotrophs and net-builders to see if they perform better in the inoculated plots.

The berm and mycorrhizal trial will be installed in February or March 2002 and will

occupy 10 acres in 5 blocks, each with 4 (0.5 acre) plots. A stratified random blocking

design will be used. The blocks will be located north and west of the nursery (Figure 23).

Each plot will contain seven evenly spaced berms oriented east to west. Berms will be

spaced 30 ft apart from their centers, and will begin 10 ft from the north edge of the plot.

A barley buffer will be maintained to the north and south of the plots. Plots will be

separate on the eastern and western sides by approximately 85’ wide strips. However,

these will be planted to barley. The berms will be continuous through adjacent plots (i.e.,

the berms do not stop within the plot boundaries, but continue into adjacent plots).
Land Retirement Demonstration Program: Year 3

72

Prior to installation of the berms, the ground will be prepared by disking and harrowing

with a spring-toothed harrow. The berms will be created using a 2-disk border disc and a

cultipacker. Plots will be imprinted with the usual restoration seed mix at the rate of 50

pounds per acre with mycorrhizal inoculum added to the designated plots.

iv. Watering trial

The watering requirements for two plant species, Atriplex polycarpa and Leymus

triticoides will be investigated. Objectives are to determine whether these species, when

transplanted from plugs: 1) require watering to survive through the first summer; and, 2)

at which point watering can be terminated while still ensuring a high survival rate.

Seedlings were grown by Westside Transplants (Firebaugh, CA) in the latter half of

2001. It is anticipated that the trial will commence in early 2002. Seedlings will be

planted along the eastern edge of the northwestern corner of Section 23 (Figure 23).

Each species will be planted in "plots" consisting of either 9 A. polycarpa or 18 L.

triticoides individuals. Spacing between plants will be 4 ft for both species. Spacing was

based on maximum planting densities as recommended by the USDA.

Plots will be arranged in a randomized block design of five blocks. Each block will

contain four plots, with each plot being assigned one of four, randomly assigned,

watering regimes. Watering will be conducted once a week. In order to facilitate

watering, plots will be situated in close proximity (ca. 25-30') from the road that

delineates the eastern side of the study area. Watering will be carried out using a pickup

truck outfitted with a small gas-powered pump and three 55-gallon tanks. Anticipated

watering rate is approximately 0.75 gallon of water/plant/week. Experimental treatments

will be: 1) no watering after the estimated final rain of the season; 2) watering for 2

months after the final rain; 3) watering for 3 months after the final rain; and, 4) watering

for 4 months after the final rain.

v. Suitability trial

To broaden the selection of species used in our restoration activities, an analysis of the

suitability of a variety of species was initiated. A list was compiled of species that had

been used in other restoration projects or which seemed to be likely candidates for

inclusion in restoration activities. The resulting 43 potential species were then ranked

based on a series of criteria (listed in alphabetical order):

• active growth period

• adapted for clay soil

• availability (from suppliers)

• cost per pound of PLS (pure live seed)

• drought tolerance

• fire tolerance

• growth rate

• known from the county
Land Retirement Demonstration Program: Year 3

73

• known from nearby reserves

• legal weed status

• life history (e.g., annual/perennial)

• life-form (e.g., shrub, forb, etc.)

• mature height

• minimum precipitation requirement

• mycorrhizal status

• pretreatment requirements

• salt tolerance

• ability to withstand high levels of sunlight

Based on this evaluation, four grasses, Elymus glaucus, E. multisetus, Nassella cernua,

and N. pulchra, and a single broadleaf species, Eriogonum fasciculatum (Polygonaceae),

were selected for planting. Bromus carinatus, a grass that we have imprinted in other

trials, was selected to serve as a control.

Installation of the trial is scheduled for late winter, 2002. Each species will be imprinted

in a 0.33-acre strip (~ 12 x 1,200 ft). In order to facilitate comparisons among species,

seeding rates will be calibrated so that each species is seeded at 35 PLS (pure live seeds)

per square foot. The trial will be monitored periodically; if species establishment is

successful it will be quantitatively sampled towards the end of the growing season.

2. Biological Monitoring

IN 2001, ESRP conducted monitoring on a site-wide basis that is not directly related to

the Tranquillity Habitat Restoration Study. Monitoring consisted of:

• spotlighting surveys;

• track station surveys;

• winter raptor surveys; and

• contaminants sampling (vegetation, invertebrates, and small mammals).

The locations where the spotlighting, track station, and winter raptor surveys were

conducted is presented in Figure 29. Because the contaminants locations are relatively

complex, the locations where sampling occurred is presented in a separate figure in the

contaminants section (section 2 d) of this document.
Land Retirement Demonstration Program: Year 3

74

Figure 29. Sampling locations for site-wide biological monitoring at the Tranquillity

site.

a. Spotlighting Surveys

i. Methods

Spotlighting surveys at the Tranquillity site were conducted on 29-31May, 17-19

September, and 17-19 December 2001 following methods that have been previously

presented (Uptain et al. 2001). The first quarter (spring) spotlighting effort was cancelled

due to heavy rains and consequent lack of access to the study site.

ii. Results

There was seasonal variability in species richness during the spotlighting surveys, but

there was also a trend of increasing species richness from 1999 to 2001 (Table 33). No

single species was present during all census periods, but barn owls (Tyto alba), black-
Land Retirement Demonstration Program: Year 3

75

tailed jackrabbits (Lepus californicus), desert cottontails (Sylvilagus audubonii), and

short-eared owls were present most seasons. Although seasonal composition of species

varied, barn owls, black-tailed hares, desert cottontails and red-tailed hawks (Buteo

jamaicensis) generally ranked within the top three most abundant species (Table 33).

Barn owls were the most abundant species during five of the nine census periods and

ranked within the top three most abundant species during seven of the census periods.

Table 33. Rates of species occurrence during 1999 to 2001 spotlighting surveys at the

Tranquillity site.

Rate1

Common name 1999 2000 2001

Fall Winter Spring Summ. Fall Winter Summ. Fall Winter

western toad 0.09 0 0.20 0.86 0.03 0 0.20 0.17 0

California king snake 0 0 0 0.03 0 0 0 0.03 0

black-crowned night

heron 0 0 0 0 0 0 0.66 0 0

burrowing owl 0.09 0.09 0.35 0.14 0 0 0 0 0

duck 0 0 0 0 0 0 0.03 0 0

egret 0 0 0 0 0 0 0.03 0 0

killdeer 0 0 0.09 0.03 0.06 0.40 0 0 0.06

lesser nighthawk 0 0 0 0 0 0 0 0.03 0

red-tailed hawk 0 0.58 0 0 0.26 0.40 0.03 0.29 0.32

western Meadowlark 0 0 0 0 0 0 0 0.09 0

black-tailed hare 0.12 0.20 0.23 0.32 0.12 0.03 0.17 0.26 0

desert cottontail 0.12 0 0.37 0.23 0.06 0.09 0.12 0.35 0.23

coyote 0 0 0.06 0 0 0.09 0.06 0 0

dog 0 0 0 0 0 0.03 0 0 0

kangaroo rat 0 0 0.03 0.23 0 0 0 0.17 0

mouse 0 0 0 0 0.03 0 0.32 0.20 0

California ground squirrel 0 0 0 0 0 0.03 0 0 0

California vole 0.03 0 0 0 0 0 0.06 0.06 0

unknown 0 0 0 0 0 0 0.03 0 0

Species Richness 7 4 8 9 8 9 13 12 4

1. Rate: mean number of observations per mile of survey.

iii. Discussion

As restoration on the Tranquillity site continues, we would expect the species

composition and abundance to shift. Greater numbers of kangaroo rats, mice, blacktailed hares, and desert cottontails would be expected. A concomitant increase in

predators would also be expected.
Land Retirement Demonstration Program: Year 3

76

b. Track Station Surveys

i. Methods

Track station surveys of the Tranquillity site were conducted on 14-16 March, 30 May-1

June, 9-11 September, and 18-20 December 2001 using methods that have been

previously presented (Uptain et al. 2001).

ii. Results

Mean species richness at the track stations was variable throughout the survey duration

(Figure 30). The lowest seasonal richness was observed in fall and winter 1999. The

highest richness was observed in summer 2000 and spring 2001, although fall 2001 also

had relatively high richness values. Similarly, the abundance of tracks at the track

stations was quite variable (Figure 31). The lowest seasonal abundance values were in

fall and winter 1999 and spring of 2000, whereas the highest seasonal abundance values

were in summer 2000. Mammals exhibited the greatest frequency of visitation and the

greatest rate of visitation, except in summer and winter 2000, when invertebrates

exhibited the greatest rate of visitation (Table 34). Reptiles were conspicuously absent

from the track stations.

Figure 30. Seasonal richness of tracks observed on the track stations at the Tranquillity

site, 1999 through 2001.
Land Retirement Demonstration Program: Year 3

77

Figure 31. Seasonal abundance of tracks observed on the track stations at the

Tranquillity site, 1999 through 2001.

Table 34. Frequency and rate of visitation of wildlife at track stations at the Tranquillity

site, 1999 through 2001.

Invertebrates Amphibians Reptiles Birds Mammals

Season Freq.1 Rate2 Freq.1 Rate2 Freq.1 Rate2 Freq.1 Rate2 Freq.1 Rate2

Fall 1999 100.0 0.18 0 0 0 0 0 0 100.0 0.14

Winter 1999 0 0 0 0 0 0 0 0 100.0 0.12

Spring 2000 33.3 0.08 0 0 0 0 33.3 0.06 33.3 0.18

Summer 2000 100.0 0.29 100.0 0.10 0 0 100.0 0.18 100.0 0.24

Fall 2000 100.0 0.21 66.7 0.06 0 0 100.0 0.04 100.0 0.16

Winter 2000 66.7 0.25 33.3 0.02 0 0 100.0 0.08 100.0 0.20

Spring 2001 100.0 0.12 66.7 0.04 0 0 100.0 0.14 100.0 0.31

Summer 2001 66.7 0.06 33.3 0.02 0 0 33.3 0.04 100.0 0.31

Fall 2001 66.7 0.16 66.7 0.04 33.3 0.02 100.0 0.06 100.0 0.31

Winter 2001 33.3 0.10 0 0 0 0 33.3 0.10 100.0 0.20

1. Frequency: the percentage of nights that tracks of a taxon were observed during a survey.

2. Rate: the number of track stations visited by a taxon divided by the total number of stations, averaged over the

number of survey nights.
Land Retirement Demonstration Program: Year 3

78

iii. Discussion

The high variability of track richness, abundance, frequency, and rate indicates that

wildlife populations on the site are not showing a clear trend of steadily increasing

numbers and not exhibiting an expansion in distribution. An increasing trend in wildlife

numbers and expanding distributions would be expected on a site-wide basis in a

response to restoration efforts, or even in response to the establishment of fallow fields.

The lack of steadily increasing wildlife numbers or increasing distributions may not

reflect responses to restoration, but rather, it may be related to the variability of seasonal

and yearly climactic conditions in the San Joaquin Valley.

c. Winter Raptor Survey

i. Methods

The annual winter raptor survey was conducted from 18-20 December 2001 following

methods that have been previously presented (Uptain et al. 2001).

ii. Results

Loggerhead shrikes (Lanius ludovicianus) and eight species of raptors were observed

during the 2001 winter survey (Table 35). American kestrel (Falco sparverius) and

northern harrier were the most prevalent raptor species observed. Red-tailed hawks,

loggerhead shrikes, and white-tailed kites (Elanus leucurus) also were frequently

observed. One peregrine falcon (Falco peregrinus), one rough-legged hawk (Buteo

lagupus), and two ferruginous hawks (Buteo regalis) comprise the uncommon species

that were recorded during the census.

Numbers of northern harriers increased slightly since 1999 (Table 35). Loggerhead

shrikes were not recorded in 1999, but have increased in rate of occurrence since the

2000 census. The occurrence rates of both American kestrels and white-tailed kites have

fluctuated throughout the 3 years of this census.

Table 35. Frequency and rate of occurrence of bird species observed at the Tranquillity

site, 1999 - 2001.

Species 1999 2000 2001

Common name Scientific name Total Freq1 Rate2 Total Freq1 Rate2 Total Freq1 Rate2

white-tailed kite Elanus caeruleus 6 66.7 17.1 15 100.0 45.0 7 100.0 18.8

ferruginous hawk Buteo regalis - - - - - - 3 66.7 8.0

prairie falcon Falco mexicanus 1 33.3 2.9 1 33.3 3.0 - - -

unidentified falcon Falco sp. - - - 1 33.3 3.0 - - -

loggerhead shrike3 Lanius

ludovicianus - - - 11 100.0 33.0 14 100.0 37.5

1. Frequency: Percent of surveys with positive observations.

2. Rate: Mean number observed per mile of survey.

3. Species not counted in 1999
Land Retirement Demonstration Program: Year 3

79

iii. Discussion

This year was the first in which either a peregrine falcon or a ferruginous hawk, both of

which are special status species, was seen on the Tranquillity site. The peregrine falcon

was observed in pursuit of a small passerine species over one of the study plots. It is

possible that both of these species have foraged on the study plots in the past, but were

not present during an avian census or noticed while other field work was being

conducted. Although the prairie falcon was not recorded during the 2001 winter raptor

survey, it was observed during the quarterly avian survey in October 2001.

Home-range size varies among raptor species and generally can be correlated with prey

availability, season, and habitat structure. Thus, fluctuations in occurrence rates at the

LRDP site for many raptor species are likely attributable to larger landscape-level factors

than to plot-level variables.

d. Contaminants Monitoring

i. Methods

Monitoring of selenium contamination of the Tranquillity site followed methods

previously presented (Uptain et al. 2001). Vegetation, invertebrate, and small mammal

samples were collected from the locations shown in Figure 32. Vegetation sampling was

conducted on 10-11 May 2001, invertebrate sampling was conducted on 19-22 June

2001, and small mammal sampling was conducted on 5-6 September 2001. The

sampling locations were classified as cultivated areas, uncultivated areas, and

experimental areas. Cultivated areas were those where barley is being grown on the site

or where other crops are being grown directly adjacent to the LRDP site. Uncultivated

areas are those that are fallowed or idled. Samples from experimental areas are those

taken directly from the HRS study plots. In previous analyses of contaminant data

collected from the Tranquillity site (Selmon et al. 2000, Uptain et al. 2001), geometric

means were not calculated for any group of data where one sample or more within a

group had a selenium level below the detection limit. This limited our ability to interpret

trends in the level of selenium contamination for several groups of data. In this report,

when a sample contained less than the detection limit, the value for that sample was set at

half the detection limit and a geometric mean was calculated for the data group.

Geometric means are used rather than standard means or medians because biota tend to

accumulate selenium in a non-linear fashion.
Land Retirement Demonstration Program: Year 3

80

Figure 32. Sampling locations for contaminant monitoring at the Tranquillity site.

ii. Results

Vegetation

There were very few vegetation samples collected from any of the three collection areas

(cultivated, uncultivated, and experimental) for selenium analysis in 1999 (Table 36).

There were a variety of reasons for this including:

• the project was begun late in the year, when many of the plant species were dead and

dried, making collections problematic,

• The cultivated and experimental areas were planted in irrigated barley, which

containing a paucity of other species
Land Retirement Demonstration Program: Year 3

81

• Project protocols were being developed, delaying implementation of some sampling,

including the collection of contaminant samples.

Selenium concentrations in the four species collected in 1999, regardless of collection

area, averaging 0.40 mg/kg or less). Similarly, in 2000 the mean selenium concentrations

in most species remained at or below 0.50 mg/kg, except for Brassica nigra from

cultivated areas, which had mean selenium concentrations of 0.96 and 1.01 mg/kg in

seeds and vegetation. Similarly, Brassica nigra also had high selenium concentrations

relative to other species in the experimental area in both 2000 and 2001. Selenium

concentrations of all species sampled did not appreciably increase from 2000 to 2001.

We combined samples from each year into groups representing selenium accumulators

(Brassica nigra, Distichlis spicata, Heliotropium curassavicum, and Sesuvium

verrucosum) and non-accumulators for each of the three areas (cultivated, experimental,

and uncultivated). This was done to increase the sample sizes (thus increasing the

robustness of the results) and to compare selenium concentrations between accumulators

and non-accumulators across sampling areas and years. Selenium concentrations in

vegetation (either whole plant or seed) did not increase from 1999 to 2001 in any of the

three collection areas at the Tranquillity site (Table 37). The group of accumulator plants

did not vary across years or sampling areas to any great degree. Furthermore, the group

of accumulator plants did not accumulate selenium at levels considered indicative of

selenium accumulators (500 to 1,000 mg/kg).
Land Retirement Demonstration Program: Year 3

82

Table 36. Selenium concentrations in plant species collected from the Tranquillity site

1999 2000 2001

Land use Taxon code1 Part

 N Min Max Mean SE N Min Max Mean SE N Min Max Mean SE

Veg 1 0.20 0.20 0.20 0.00 ATAR

Whole 5 0.10 0.63 0.37 0.11

AVFA Whole 5 0.20 0.40 0.33 0.04

Seeds 4 0.64 1.60 0.96 0.22 BRNI

Veg 4 0.30 1.70 1.01 0.32

Seeds 5 0.10 0.40 0.24 0.05 5 0.10 0.50 0.20 0.07 HOVU

Veg 5 0.10 0.63 0.26 0.09 11 0.30 1.30 0.43 0.09

MEIN Veg 3 0.10 0.40 0.16 0.10

Cultivated

SIIR Veg 1 0.40 0.40 0.40 0.00

Veg 2 0.10 0.50 0.22 0.20 1 0.50 0.50 0.50 0.00 4 0.10 1.10 0.34 0.23 ATAR

Whole 4 0.10 0.40 0.26 0.07

ATPO Veg 4 0.10 1.00 0.28 0.20AVFA Whole 5 0.10 0.50 0.25 0.07BEVU Whole 4 0.10 0.73 0.33 0.13BRMA Seeds 1 0.10 0.10 0.10 0.00

Seeds 4 0.40 0.50 0.42 0.03 1 0.50 0.50 0.50 0.00 BRNI

Veg 4 0.10 0.88 0.44 0.18 1 0.60 0.60 0.60 0.00

HOMU Whole 1 0.10 0.10 0.10 0.00

Seeds 5 0.10 0.30 0.20 0.04 5 0.10 0.40 0.17 0.07 HOVU

Veg 5 0.10 0.40 0.20 0.05 5 0.10 0.50 0.18 0.09

Experimental

SUMO Veg 5 0.30 2.60 0.51 0.45
Land Retirement Demonstration Program: Year 3

83

1999 2000 2001

Land use Taxon code1 Part

 N Min Max Mean SE N Min Max Mean SE N Min Max Mean SE

Veg 3 0.10 0.50 0.17 0.13 5 0.10 0.30 0.16 0.04 ATAR

Whole 5 0.10 0.20 0.11 0.02

Seeds 5 0.10 0.10 0.10 0.00 BRMA

Whole 5 0.10 0.20 0.11 0.02

Seeds 5 0.10 0.60 0.20 0.09 5 0.10 0.30 0.18 0.04 BRNI

Veg 5 0.10 0.40 0.19 0.06 5 0.10 0.50 0.26 0.07

Seeds 1 0.10 0.10 0.10 0.00Veg 1 0.10 0.10 0.10 0.00 1 0.40 0.40 0.40 0.00

HECU

Whole 5 0.10 0.40 0.19 0.06

HOMU Whole 3 0.10 0.30 0.14 0.07MEIN Veg 5 0.10 0.30 0.17 0.05

Seeds 3 0.10 0.20 0.16 0.03

Uncultivated

PHDI

Veg 3 0.15 0.30 0.21 0.04

1. Vegetation taxonomic codes: ATAR-Atriplex argentea, AVFA-Avena fatua, BRNI-Brassica nigra, HOVU-Hordeum vulgaris, MEIN-Melilotus indica, SIIRSisymbrium irio, ATPO-Atriplex polycarpa, BEVU-Beta vulgaris, BRMA-Bromus madritensis var. rubens, HOMU-Hordeum murinum, SUMO-Suaeda moquinii,

HECU-Heliotropium curassavicum, PHDI-Phacelia distans.
Land Retirement Demonstration Program: Year 3

84

Table 37. Selenium concentrations in plant species grouped as selenium accumulators and selenium non-accumulators at the

Tranquillity site

1999 2000 2001

Land use Accum. Part

 N Min Max GM SE N Min Max GM SE N Min Max GM SE

Seeds 5 0.10 0.40 0.24 0.05 5 0.10 0.50 0.20 0.07Veg 1 0.20 0.20 0.20 0.00 6 0.10 0.63 0.30 0.09 14 0.10 1.30 0.35 0.08

No

Whole 1 0.40 0.40 0.40 0.00 9 0.10 0.63 0.33 0.06

Seeds 4 0.64 1.60 0.96 0.22

Cultivated

Yes

Veg 4 0.30 1.70 1.01 0.32

Seeds 5 0.10 0.30 0.20 0.04 5 0.10 0.40 0.17 0.07 1 0.10 0.10 0.10 0.00Veg 7 0.10 0.50 0.21 0.06 6 0.10 0.50 0.22 0.08 13 0.10 2.60 0.37 0.19

No

Whole 14 0.10 0.73 0.26 0.05

Seeds 4 0.40 0.50 0.42 0.03 1 0.50 0.50 0.50 0.00

Experimental

Yes

Veg 4 0.10 0.88 0.44 0.18 1 0.60 0.60 0.60 0.00

Seeds 8 0.10 0.20 0.12 0.02Veg 3 0.10 0.50 0.17 0.13 1 0.10 0.10 0.10 0.00 13 0.10 0.30 0.17 0.02

No

Whole 12 0.10 0.30 0.12 0.02

Seeds 1 0.10 0.10 0.10 0.00 5 0.10 0.60 0.20 0.09 5 0.10 0.30 0.16 0.05Veg 1 0.10 0.10 0.10 0.00 5 0.10 0.10 0.19 0.06 6 0.10 0.50 0.28 0.06

Uncultivated

Yes

Whole 3 0.10 3.90 1.12 1.22
Land Retirement Demonstration Program: Year 3

85

Invertebrates

Selenium concentrations in the four groups of invertebrates sampled (beetles, crickets, isopods,

and spiders) did not vary from 1999 to 2001 (Table 38, Figure 33). However, there is a slight

trend of increasing selenium levels in all groups except spiders. Isopods exhibited the highest

concentrations of selenium levels in all years.

Figure 33. Selenium concentrations in invertebrates sampled from the Tranquillity site.
Land Retirement Demonstration Program: Year 3

86

Table 38. Selenium concentrations in invertebrate species collected from the Tranquillity site

1999 2000 2001

Land use Taxon

group

Part

 N Min Max mean SE N Min Max mean SE N Min Max mean SE

Beetles Body 2 0.50 1.20 0.77 0.35 5 0.60 2.70 1.27 0.35 5 0.70 2.80 1.35 0.38

Crickets Body 4 0.30 0.60 0.40 0.07 5 0.40 1.20 0.72 0.07 5 0.50 1.80 0.81 0.23

Isopods Body 3 1.00 5.60 2.53 1.33 5 2.20 4.50 3.23 1.33 5 2.10 13.00 3.46 2.10 Experimental

Spiders Body 5 1.10 3.60 2.24 0.43 5 0.90 2.70 1.91 0.43 5 0.95 3.20 1.93 0.41

Small mammalsBody and liver samples of small mammals collected from all sample locations (cultivated, uncultivated, and experimental) did not

vary in selenium concentrations from 1999 to 2001 (Table 39). However, there are trends of decreasing concentrations of selenium in

all groups sampled for all sample locations. ). The selenium levels in all small mammals captured during all seasons remain below thelevel considered to be problematic (5 ppm).Table 39. Selenium concentrations in mammal species collected from the Tranquillity site

1999 2000 2001

Land use Taxon code1 Part N Min Max mean SE N Min Max mean SE N Min Max mean SE

Body 5 1.00 1.50 1.21 0.08 5 0.95 1.70 1.42 0.14 6 0.91 1.40 1.19 0.08 Cultivated PEMA

Liver 5 3.30 3.90 3.57 0.10 5 3.10 5.50 3.84 0.42 6 2.30 3.80 3.11 0.20

Body 13 2.00 4.80 2.51 0.21 6 1.60 2.90 1.95 0.19 Experimental SOOR

Liver 13 3.40 7.80 4.18 0.34 6 2.90 5.80 3.65 0.45

Body 5 0.75 1.10 0.94 0.07 5 0.73 1.00 0.82 0.05 5 0.50 0.85 0.63 0.06 Uncultivated PEMA

Liver 5 2.90 4.40 3.58 0.28 5 1.60 3.90 2.67 0.42 5 0.74 2.30 1.56 0.29

1. Mammal taxonomic codes: PEMA-Peromyscus maniculatus (deer mice), SOOR-Sorex Ornatus (ornate shrew)
Land Retirement Demonstration Program: Year 3

87

iii. Discussion

The results of our monitoring to date indicate that bio-accumulation of selenium does not

appear to be a concern on retired agricultural land at the Tranquillity site. .Selenium

levels in most biotic groups sampled on the Tranquillity site generally fall within the

range of typical background levels. Typical background levels of selenium in terrestrial

plants range from 0.01 - 0.6 mg/kg (USDI 1998). Brassica nigra collected from

cultivated areas exceeded this range, but B. nigra is a known selenium accumulator.

Known selenium accumulators can accumulate selenium to levels as high as 500 - 1,000

mg/kg (Rosenfeld and Beath 1964), far exceeding the levels observed in B. nigra.

Typical background selenium levels of terrestrial invertebrates are 0.1 - 2.5 mg/kg. The

mean (geometric mean) selenium level of beetles and crickets fell within this range, but

selenium levels in isopods and spiders slightly exceeded this range. Selenium levels in

spiders and isopods are expected to exceed those in beetles and crickets because of

dietary differences that lead to bio-accumulation of selenium. Beetles and crickets

generally feed on vegetation whereas spiders are predatory and isopods feed on detritus.

Typical background levels of selenium in small mammals are <1.0 - 4.0 mg/kg for whole

body samples and 1.0 - 10.0 mg/kg for liver samples (USDI 1998). The mean selenium

levels of body and liver samples from both deer mice and shrews are at the lower end of

these ranges.

3. Management

a. Cover Crop Production

In 2001, barley was grown as a cover crop on the 80-acre parcel located along Manning

Avenue and in a 40-acre parcel east of the study plots. The barley on both sites was

harvested in June. In the winter of 2001-2002, the 80-acre parcel was planted with a

restoration mix and the 40-acre parcel was used as a berm trial area, native plant nursery,

and barley/seed mix strip trial area (see section III A 1).

b. Grazing

No managed grazing occurred on the LRDP Tranquillity site in 2001. However, trespass

grazing did occur in the 160-acre restoration area that is located southeast of the HRS

study blocks. The sheep owner had permission to graze sheep south of South Avenue

from Westlands Water District and inadvertently encroached upon project lands.

Temporary fencing was erected on the parcel and sheep were grazed for a total of 4 days

from 8-11 October 2001. The level of grazing was intense enough to virtually denude the

parcel of all vegetation. Fortunately, the native plants that germinated from the

restoration effort had gone to seed and disarticulated prior to the grazing. Additionally,

most of the shrub seedlings that were planted did not survive, although grazing did

destroy the few seedlings that persisted. The sheep also trampled and destroyed the

majority of the low berms that had been installed in the parcel. Monitoring of the site

will occur in spring 2002 to determine if native annual plants remain on the site and to

determine the effects of grazing on the non-native weeds (mostly Sisymbrium and

Brassica) that dominated the site.
Land Retirement Demonstration Program: Year 3

88

c. Recreational Uses

The California Department of Fish and Game has annually planted approximately 60

acres of the Tranquillity site in safflower. The safflower field is used for an annual junior

dove hunt in September. In 2001, 35 hunters harvested 213 dove during the hunt.
Land Retirement Demonstration Program: Year 3

89

B. Atwell Island

1. Restoration Studies

a. Small Test Plots

During the Fall of 2001 USBLM established a series of 456, 1/1000-acre (6ft 7in x 6ft

7in) test plots in the southwest quarter of Section 23 (Figure 34). Seed from 29 species of

shrubs, forbs, and grasses were planted in the plots. Four types of site preparation were

used:

• scraping the surface;

• disking to 8 inches;

• harrowing to 4 inches; and

• no preparation.

Figure 34. Locations of restoration studies conducted at the Atwell Island site.

A standard seeding rate of 40 pounds/acre was used on these plots for each site

preparation. On the scraped area, in addition to the 40 pounds/acre seeding rate, plots

with other seeding rates were established: 1) 10 pounds/acre, 2) 80 pounds/acre, and 3)

160 pounds/acre. On the disked area, plots with added nutrients were established. Bone

meal was used to increase soil phosphorus content and blood meal was used to increase

soil nitrogen content. Rates of 500 and 1,000 lbs/ac effectively doubled and tripled the
Land Retirement Demonstration Program: Year 3

90

available soil phosphorus and nitrogen in the soil. An additional treatment of 500 lbs/ac

of both blood and bone meal was used.

These test plots are being used as a screening technique to look for broad effects and are

the first step of a tiered approach. This year's work will be used to search for interesting

trends and to help focus future, more in-depth, research. In the second year, if promising

species or trends have emerged, USBLM will set up more in-depth trials involving those

species and treatments. In this second stage an experimental approach with replicates

will be used.

Plots will be monitored by USBLM during the spring of 2002 and in succeeding years.

Additional plots will be established in fall of 2002 to look at various weed competition

factors and several seed mixes.

b. Hedgerows

During February of 2001, six 0.25-mile long hedgerows were planted in the northeast

quarter of Section 10 (Figure 34). This was done using a Rhino plow to dig the ditches

and then a Truax range drill to seed over the ditches with a commercial hedgerow mix

(60% bran and 40% native seed). The seed mix contained 29% quail bush (Atriplex

lentiformis), 22% creeping wildrye (Leymus triticoides), 14% few-flowered fescue

(Vulpia microstachys), 14% fiddleneck (Amsinkia menziesii), 7% common sunflower

(Helianthus annus), 7% alkali heath (Frankenia salina), 4% turkey mullein

(Eremocarpus setigerus), 1% bluedicks (Dichelostemma capitatum), and 1% spikeweed

(Hemizonia pungens). The ditches were watered twice, once in May and once in July.

These hedgerows were very successful, with good coverage of sunflower and excellent

growth and establishment of quail bush, many of which reached 1.0 m in height by

February 2002. As a result of this success, we will establish an additional 38, 0.5-mile

long hedgerows in the south east quarter of Section 10 (Figure 34) in 2002. These will be

planted in two configurations; a series of four ditches 6 ft apart and single wavy line

ditches. Six hedgerows will be seeded with the commercial mix and the remaining

ditches will be seeded with a combination of wild-collected quail bush (25%), valley salt

bush (25%), sunflower (35%), and alkali sacaton (15%) at a rate of approximately 30

pounds per acre. These hedgerows will be watered two or three times during the season,

starting in early March 2002. Approximately 20 acres of this 160 acre quarter section

will be planted, but the hedgerows are spread throughout the quarter section.

c. Seeding Restoration Mix

The USBLM seeded a total of 160 acres with restoration mix in January 2001 using a

Truax range drill (Figure 34). Only moderate germination was observed, probably due to

the lack of spring rain. This site will be monitored in spring 2002.

In late November 2001, 80 acres in Section 23 were seeded. Forty acres were seeded

with the restoration mix at approximately 30 pounds/acre and 40 acres with local wildcollected spikeweed seed. The commercial restoration mix was purchased from S&S

Seed Company and consisted of 7% Eremocarpus setigerus, 3% Sporobolus airoides, 2%

Frankenia salina, 0.3% Hemizonia pungens, 1.5% Lasthenia californica, 9% Atriplex
Land Retirement Demonstration Program: Year 3

91

polycarpa, 9% Atriplex spinifera, 3% Vulpia microstachys, 3% Gilia tricolor diffusa, 3%

Suaeda moquinii, 3% Isocoma acradenia, and 56% bran. The restoration mix was seeded

at a rate of 11.1 pounds of seed/acre. All except four seeding passes were made with the

imprinter. The range drill was used on four passes, but was discontinued because the soil

was too moist causing the planter to clog. As of mid-February 2002, germination of

these plantings has been excellent. The range-drilled areas appear to have better

germination than the imprinted areas, primarily because the range drill did a better job at

clearing residual vegetation from the soil.

In three areas, approximately 30 by 90 ft in extent, residual and green vegetation was

burned off using a hand-held propane torch immediately prior to planting. An inspection

in early February 2002 showed germination similar to that of the non-burned areas. By

late February 2002, survival and growth of seedlings was much higher on the burned

areas than on non-burned plots. Native species observed were Vulpia sp., Gilia sp.,

Lasthenia sp.(included in seed mix), and California Mustard (Guillenia lasiophylla; not

in the seed mix).

d. Shrubs and Trees with Drip Irrigation

Approximately 150 cuttings (rooted in supercells—10 in deep plastic containers) of

native trees and shrubs were planted along the Alpaugh Irrigation District Canal in

Section 14 (Figure 34). Drip irrigation was installed and the plantings were watered with

a small portable pump, with the water pumped from the canal. Quail Bush shrubs had

high survival and good growth rates, reaching 3 ft in height. The cottonwoods and

Baccharis salicifolia plantings had zero survival, primarily because of a grasshopper

plague in mid-summer. The grasshoppers ate the leaves and the bark of the trees and

shrubs. It is likely that this was an aberrant situation and the planting will be re-tried in

2002.

Additional plantings with 8-ft-long poles will be done along the canal in Section 10 using

a hydraulic auger in March 2002. This method places the rooting zone of the plant in

ground water seepage from the canal, thus avoiding the need for drip irrigation.

e. Shrub Islands with Drip Irrigation

During fall 2001, a drip irrigation system to help establish shrub islands was placed on

the 80 acres that were planted with the range drill in Section 23 (Figure 34). Twelve

lines, each 1,000 ft long with a total of 1,400 emitters, were installed. The purpose of this

irrigation system is to provide supplemental water to help increase survival of shrubs

through their first growing season. Seedlings were planted at approximately 300

emitters, while at the other 1,100 emitters seeds were planted. Seedlings were primarily

Atriplex polycarpa, Isocoma acradenia, and Sporobolus airoides, with some Atriplex

lentiformis. Seed was composed of both native and commercial Atriplex polycarpa and

Atriplex lentiformis.
Land Retirement Demonstration Program: Year 3

92

f. Alkali Sacaton Transplants

A patch of 266 alkali sacaton (Sporobolus airoides) seedlings was planted along sand

ridge in Section 11 in mid-January 2002 (Figure 34). These plants will be watered during

the first growing season.

g. Evaporation Basin Restoration

The Evaporation Basin—an approximately 33-acre former evaporation basin located

along the western edge of the Atwell Island LRDP property (Figure 34)—was targeted

for a cursory restoration trial in late 2001. The evaporation basin is characterized by a

flat expanse of highly alkaline, salt-encrusted soil, nearly devoid of vegetation; however,

adjacent lands, which are managed by the USBLM, support fair-sized populations of

native alkali sink vegetation. The Evaporation Basin was in intermittent closure in 1999,

and has had no discharges from tile drains since 1994. Selenium levels were tested in

1994 and were found to be below the detection limit (Interagency Land Retirement Team

1999).

Restoration efforts conducted by ESRP occurred during November and December 2001.

Only outer edges of the evaporation basin were accessible, as rainfall at that time had

created extremely wet and muddy conditions. Vegetation was introduced to the site by

both seeding and transplanting. Areas to be seeded were prepared by loosening the soil

with rakes. Native seed from adjacent properties was collected and then broadcast onto

the raked seedbeds. Species planted in this manner were: Allenrolfea occidentalis,

Distichlis spicata, Frankenia salina, Heliotropium curassavicum, and Suaeda moquinii.

Two of these, Distichlis spicata and Allenrolfea occidentalis, also were introduced to the

site through transplanting. Rhizomes of D. spicata that were growing along the perimeter

and encroaching onto the salt flat were transplanted onto the restoration area. Plugs of

Allenrolfea occidentalis were grown by the Southern California Edison Nursery

(Auberry) from native seed collected from the Tranquillity area, and were transplanted

directly onto the site. At this time, there are no plans to conduct quantitative sampling at

the site; rather, the success of the restoration will be monitored non-systematically.

Additional planting efforts will be conducted in the evaporation basin as time and

resources permit.

h. Native Seed Collection

During 2001 USBLM contracted with four seed collectors to collect native seed in the

southern San Joaquin Valley. The spring collection in the Goose Lake area netted 90

pounds of goldfields (Lasthenia californica) seed, 0.5 pounds of few-flowered fescue

(Vulpia microstachys) seed, and 1.5 pounds of slender-hair grass (Deschampsia

danthonioides) seed. The early fall seed collections yielded 202 pounds of bush

seepweed (Suaeda moquinii), 778 pounds of spiny saltbush (Atriplex spinifera), 78

pounds of alkali heath (Frankenia salina), 379 pounds of spikeweed (Hemizonia

pungens), 1 pound of alkali sacaton (Sporobolus airoides), 124 pounds of alkali mallow

(Malvella leprosa), 3.2 pounds of alkali heliotrope (Heliotropium curassavicum), 1

pound of slender-leaf milkweed (Asclepias fascicularis), 277 pounds of common

sunflower (Helianthus annuus), and 5 pounds of goldenbush (Isocoma acradenia). The
Land Retirement Demonstration Program: Year 3

93

late fall seed collecting yielded 404 pounds of valley saltbush (Atriplex polycarpa) and

148 pounds of quail bush (Atriplex lentiformis). The weights given above are for cleaned

seed, but some chaff and seed husks are included (the amount varies by species).

Nearby natural areas that will serve as reference and seed source sites for restoration

efforts include Kern National Wildlife Refuge, Pixley National Wildlife Refuge,

Allensworth State Ecological Reserve, and other southern San Joaquin Valley sites

managed by California Department of Fish and Game and the Center for Natural Lands

Management.

2. Biological Monitoring

ESRP conducted monitoring on a site-wide basis in 2001, which was not directly related

to the Atwell Island Habitat Restoration Study. Monitoring consisted of:

• spotlighting surveys;

• track station surveys;

• winter raptor surveys;

• contaminants sampling (vegetation, invertebrates, and small mammals).

Locations of these sampling activities is presented in Figure 35. Additionally, USBLM

conducted a winter bird count and constructed a database to record incidental wildlife

observations.

Figure 35. Sampling locations for site-wide biological monitoring at the Atwell Island

site.

a. Spotlighting Surveys

i. Methods

Spotlighting surveys of the Atwell Island site were conducted on 17-19 September and

10-12 December following methods that have been previously presented (Uptain et al.

2001).

ii. Results

The most commonly observed species during September spotlighting were barn owls,

kangaroo rats, western toads, and desert cottontails (Table 40). During December

spotlighting, the most common species observed were desert cottontails, barn owls,

black-crowned night herons (Nycticorax nycticorax), black-tailed jackrabbits, and great

egrets (Ardea alba). The number of species observed in September (18) was greater than

the number observed in December (15) and there were differences in species

composition.
Land Retirement Demonstration Program: Year 3

94

Table 40. Frequency and rate of animals observed during spotlighting surveys at the

Atwell Island site, 2001.

Fall 2001 Winter 2001

Taxon

Frequency1 Rate2 Frequency1 Rate2

bats 66.7 0.08 0 0

black-crowned night heron 66.7 0.14 66.7 0.21

black-tailed hare 100.0 0.12 66.7 0.21

burrowing owl 66.7 0.05 100.0 0.12

carp 33.3 0.02 0 0

cat 0 0 33.3 0.02

coyote 100.0 0.05 33.3 0.04

deer mouse 33.3 0.04 0 0

desert cottontail 100.0 0.16 100.0 0.46

dog 66.7 0.05 33.3 0.07

great blue heron 33.3 0.02 33.3 0.02

great egret 66.7 0.04 100.0 0.20

kangaroo rat 100.0 0.25 33.3 0.02

killdeer 33.3 0.02 0 0

prairie falcon 0 0 33.3 0.02

red-tailed hawk 0 0 100.0 0.07

snowy egret 0 0 66.7 0.11

western meadowlark 100.0 0.09 100.0 0.21

1.Frequency: percent of surveys with positive observations.

2.Rate: mean number observed per mile of survey.

iii. Discussion

Rates of observation (an index of abundance), frequency of observation, and species

composition are expected to differ seasonally. As expected, each of these indices

decreased from September to December. As restoration efforts are expanded, we would

expect increases in small mammals, birds, and predators on those species.

b. Track Station surveys

i. Methods

Track station surveys of the Atwell Island site were conducted on 18-20 September and

11-13 December following the methods presented previously (Uptain et al. 2001).

ii. Results

The greatest abundance of tracks and the greatest variety of species were observed during

the September survey period. The most abundant tracks observed in September were of

mice, insects, kangaroo rats, and toads. The most abundant tracks observed in December
Land Retirement Demonstration Program: Year 3

95

were of mice, birds, and dogs. The frequency and rate of visitation of invertebrates,

amphibians, and reptiles were higher in fall than in winter (Table 41). Likewise, the rate

of visitation (but not frequency) for birds and mammals was higher in the fall.

Table 41. Results of track station surveys at the Atwell Island site, 2001.

Fall 2001 Winter 2001

Taxon Frequency1 Rate2 Frequency1 Rate2

Invertebrates 100.0 0.17 33.3 0.04

Amphibians 100.0 0.13 0 0

Reptiles 33.3 0.04 0 0

Birds 100.0 0.11 100.0 0.09

Mammals 100.0 0.30 100.0 0.13

Unknown 0 0 66.7 0.04

1. Frequency: the percentage of nights that tracks of a taxon were observed during a survey.

2. Rate: the number of track stations visited by a taxon divided by the total number of stations, averaged over the

number of survey nights.

iii. Discussion

We expect that the variety of species and abundance of tracks at the track stations will

increase as restoration efforts at the site proceed. Invertebrates, mice, birds, and

carnivore visits are especially likely to increase.

c. Winter Raptor Survey

i. Methods

Winter raptor surveys of the Atwell Island site were conducted from 11-13 December

2001 and followed methods presented previously (Uptain et al. 2001).

ii. Results

Eight species of raptors, along with loggerhead shrikes, were documented on the winter

raptor survey route (Table 42). Though technically a passerine species, loggerhead

shrikes are considered to be an avian predator and are included in this census. The

predominant raptors observed were red-tailed hawks and northern harriers (Table 42).

American kestrels, white-tailed kites, and loggerhead shrikes were identified each of the

three survey dates, but in lower numbers than the former two species. Prairie falcons

(Falco mexicanus), and ferruginous hawks were observed intermittently throughout the

census. A single red-shouldered hawk was detected on the first day of the census. Four

species recorded on this census are considered species of special concern in California

(CSC) or federal special concern species (FSC): loggerhead shrike (FSC, CSC),

ferruginous hawk (FSC, CSC), prairie falcon (CSC), and northern harrier (CSC).
Land Retirement Demonstration Program: Year 3

96

Table 42. Number of observations, frequency, and rate of wintering raptors at the Atwell

Island site, 2001.

Species December Total1 Frequency2 Rate3

White-tailed Kite Elanus caeruleus 2 4 3 9 100 0.14

Northern harrier Circus cyaneus 12 13 12 37 100 0.56

Ferruginous Hawk Buteo regalis 2 3 0 5 67 0.08

Loggerhead Shrike Lanius ludovicianus 3 9 6 18 100 0.27

Unidentified 2 2 2 6 100 0.09

Total number observed 44 59 57 160

1. Number of observations: total seen per day and total seen during the 3-day survey.

2. Frequency: percent of surveys with positive observations.

3. Rate: mean number seen per mile of survey route.

iii. Discussion

American kestrels, northern harriers, and a single prairie falcon were observed foraging

on, or adjacent to, the study plots. All three species are known to feed on small birds

along with other prey items. Large flocks of horned larks, which were present on some

of the study plots, may be providing a prey source for these three raptors. Red-tailed

hawks, white-tailed kites, and northern harriers all were observed performing aerial

displays over LRDP lands. White-tailed kites begin courtship behavior and nest building

in December and January (Dunk 1995); hence, it is conceivable that these displays

represented pair-bonding.

The red-shouldered hawk was an unexpected species considering the open habitat that

occurs along the survey route. Red-shouldered hawks typically occur in riparian forests

or oak woodlands (Kauffman 1996). This individual was flushed from an open, brushy

area along the route that is not representative of its normal habitat. However, a narrow

strip of marginal riparian habitat does exist within the vicinity that may support this

individual.

The timing of this survey reflects the propensity of numerous raptor species to winter in

this region. However, this census is not a complete representation of all raptors using

LRDP lands. Species such as Swainson's hawk (Buteo swainsoni) may forage over the

project site during the breeding season, but migrate south during the winter months.

Thus, this species probably would be absent during the census.

d. Mid-winter Bird Count

An 8-hour bird count was conducted by USBLM personnel and volunteers on 26

December 2001. A total of 71 bird species were found during the day and 4,190

individual birds were recorded. The most common species were: red-winged blackbird

(1,408), house finch (362), white-crowned sparrow (314), savannah sparrow (291),

horned lark (184), and European starling (176). This count will be repeated yearly. In
Land Retirement Demonstration Program: Year 3

97

the future, two or three groups will be recruited to help with the count in order to get

better coverage of the area.

e. Incidental Wildlife Sighting Database

Beginning in August 2001, USBLM started a database to keep track of incidental wildlife

sightings. As of February 2002, 681 observations have been made, recording 102 species

of birds, 5 species of mammals, 2 species of reptiles, and 5 species of butterflies on the

Atwell Island Project Area. Noteworthy sightings include merlin, Swainson's hawk,

prairie falcon, white-tailed kite, white pelican (Pelecanus erythrorhynchos), white-faced

ibis (Plegadis chihi), Virginia rail (Rallus limicola), sandhill crane (Grus canadensis),

redhead (Aythya americana), long-billed curlew (Numenius americanus), herring gull

(Larus argentatus), yellow warbler (Dendroica petechia), chestnut-collared longspur

(Calcarius ornatus), and coast horned lizard.

f. Contaminants Monitoring

i. Methods

Monitoring of selenium contamination of the Atwell Island site was conducted on 16

May (vegetation) and 12-13 June 2001 (invertebrates). Methods were previously

presented (Uptain et al. 2001). Vegetation, invertebrate, and small mammal samples

were collected from the locations shown in Figure 36. Sampling locations were classified

as cultivated areas, uncultivated areas, and experimental areas. Samples were collected

in both 2000 and 2001 to provide information on baseline conditions. For analysis, plants

were grouped as selenium accumulators (those plant species known to accumulate

selenium in their tissues), and non accumulators. Small mammal tissues that were

collected in 2001 spoiled prior to being frozen in the lab. Therefore, a representation of

baseline conditions of selenium contamination in small mammals at the Atwell Island site

was derived solely from data collected in 2000 during the pre-project inventory (see

Appendix A in Uptain et al. 2001). In previous reports (Selmon et al. 2000, Uptain et al.

2001), geometric means of contaminant samples were not calculated on a group of data

whenever one or more samples within the group had a selenium level below the detection

limit. In this report, when a sample contained less than the detection limit, the value for

that sample was set at half of the detection limit and the geometric mean was calculated

for the data group.
Land Retirement Demonstration Program: Year 3

98

Figure 36. Locations of selenium sampling at the Atwell Island site.

ii. Results

The geometric means of the samples collected for all taxa had selenium concentrations

within the range of typical background levels (see Table 43, Table 44, Table 45 and

section III A d iii of this report). Furthermore, all taxa exhibited trends of declining

selenium levels between 2000 and 2001 (except small mammal data because no data

were available for 2001).
Land Retirement Demonstration Program: Year 3

99

Table 43. Selenium levels in samples of vegetation collected from the Atwell Island site

during baseline surveys in 2000 and 2001.

2000 2001

Land use Taxon code Part

 N Min Max Mean SE N Min Max Mean SE

ATAR Veg 3 0.1 0.1 0.1 0.000

HOMU Seeds 3 0.1 0.1 0.1 0.000

HOVU Seeds 3 0.1 0.1 0.1 0.000

Veg 3 0.1 0.1 0.1 0.000

Cultivated

MEIN Veg 3 0.1 0.1 0.1 0.000

ATAR Whole 10 0.1 0.4 0.11 0.030 3 0.1 0.3 0.14 0.067

BRMA Seeds 3 0.1 0.2 0.13 0.033

Veg 1 0.1 0.1 0.1 0.000

Seeds 5 0.1 0.1 0.1 0.000

Veg 4 0.2 0.5 0.3 0.075

BRNI

Whole 1 0.1 0.1 0.1 0.000

CRTR Whole 9 0.1 0.3 0.13 0.029

DISP Whole 5 0.05 1.4 0.17 0.259

HECU Veg 3 0.1 0.1 0.1 0.000

HEPU Veg 3 0.1 0.2 0.13 0.033

Whole 8 0.05 0.2 0.08 0.018

HOMU Seeds 3 0.1 0.3 0.14 0.067

Whole 10 0.05 0.1 0.09 0.005

MEIN Veg 1 0.1 0.1 0.1 0.000

Whole 10 0.05 0.15 0.09 0.009

Uncultivated

SIIR Whole 4 0.05 0.1 0.08 0.013

1. Vegetation taxonomic codes: ATAR-Atriplex argentea, HOMU-Hordeum murinum, HOVU-Hordeum vulgaris,

MEIN-Melilotus indica, BRMA-Bromus madritensis var. rubens, BRNI-Brassica nigra, CRTR-Cressa truxillensis,

DISP-Distichlis spicatum, HECU-Heliotropium curassavicum, SIIR-Sisymbrium irio.
Land Retirement Demonstration Program: Year 3

100

Table 44. Selenium levels in samples of invertebrates collected from the Atwell Island

site during baseline surveys in 2000 and 2001.

2000 2001

Land use Taxon

group

Part

N Min Max mean SE N Min Max mean SE

Beetles Body 8 0.04 0.4 0.13 0.051

Crickets Body 9 0.1 0.45 0.18 0.037

Isopods Body 9 0.07 0.6 0.33 0.067

Uncultivated

Spiders Body 9 0.29 1 0.55 0.075

Beetles Body 10 0.1 1 0.49 0.125

Crickets Body 3 0.2 1 0.39 0.252

Isopods Body 12 0.1 1.5 0.38 0.104

Experimental

Spiders Body 11 0.35 2.5 0.81 0.227

Table 45. Selenium levels in samples of small mammals collected from the Atwell

Island site during baseline surveys in 2000 and 2001.

2000

Land use Taxon group Part

N Min Max mean SE

Body 10 0.5 0.82 0.68 0.034

Uncultivated Peromyscus maniculatus

(deer mice) Liver 10 1.9 3.4 2.37 0.151

iii. Discussion

Data for the Atwell Island site will be collected in 2002 and compared to the baseline

data presented here. It is expected that selenium levels will continue to decline, as has

occurred on the Tranquillity site.

3. Management

a. Controlled Burning

The USBLM completed an Environmental Assessment (USBLM 2001) for controlled

burning on the project area. A controlled burn was conducted by a USBLM fire crew

along a canal on the south side of Section 23 in mid-November 2001.

b. Game Bird Heritage Program Dove Hunt

During the summer of 2001, safflower was planted on 60 acres and barley was planted on

10 acres of Section 10 (see Figure 34). This was a cooperative project between USBLM

and California Department of Fish and Game, with USBLM furnishing the water and
Land Retirement Demonstration Program: Year 3

101

labor and CDFG purchasing the seed. The safflower was grown with approximately 0.5

acre-feet of water applied in pre-planting irrigation. The lack of spring rain was

responsible for poor seed production of the safflower. The plants grew to normal size

and produced abundant seed heads, but most heads had only one or two seeds and most

seeds were "blanks" (i.e. only the shell had formed and there was no seed inside). The

hunt was conducted on opening day of dove hunting season in early September. Twenty

seven hunters attended the hunt and harvested only 13 doves. This cooperative project

will be repeated during 2002, but the site will be moved to a location with better soil and

closer to roosting sites along the Alpaugh Irrigation District Canal in Section 5.
Land Retirement Demonstration Program: Year 3

102

IV. PHYSICAL IMPACTS

A. Tranquillity Site

1. Tranquillity Site Geology

The Tranquillity Demonstration Project site is located in the western San Joaquin Valley,

an asymmetrical basin bounded by the Coast Ranges on the west, the Tehachapi

Mountains on the south, the Sierra Nevada on the east and the delta of the San Joaquin

and Sacramento Rivers on the north. The axis of the valley trough is closer to the Coast

Ranges than to the Sierra Nevada. The basin is filled with alluvium overlying older

Mesozoic and Cenozoic marine and continental sediments. Alluvial deposits underlying

the central San Joaquin Valley were shed from the adjacent Coastal and Sierra Nevada

ranges and vary in thickness from 900 to 3,300 ft (Miller et al.1971). The Sierra Nevada

consists mainly of granitic and metamorphic rocks of pre-Tertiary age. The Coast

Ranges are composed primarily of folded and faulted beds of Cretaceous age marine

shale and sandstone in the north and Cenozoic age sandstone and shale in the south

(Prokopovich 1987). Bull (1964a and b), identified a series of alluvial fans derived from

sediments from the coastal ranges that form the western margin of the San Joaquin Valley

in the study area.

The Tranquillity demonstration site is located in the trough of the San Joaquin valley in

Western Fresno County. The site is underlain directly by flood basin deposits derived

from overbank deposition from the San Joaquin River and Fresno Slough. The flood

basin deposits consist of fine textured, moderately to densely compacted clays that range

in thickness from 5 to 35 ft (Belitz and Heimes 1990). The flood basin clays have low

permeability and greatly impede the downward movement of water. On the northern part

of the site (in Section 10), the flood basin deposits rest upon well sorted micaceous sand

derived from the Sierra Nevada . The Sierran sands are highly permeable, reduced in

oxidation state, and vary in thickness between 400 to 500 ft in the project vicinity. On

the southern part of the site (in Sections 15 and 16), the flood basin deposits overlie

sediments derived from the coastal ranges. The coastal range sediments inter-finger with

Sierran sands in the project vicinity, and are oxidized and primarily fine grained. The

Corcoran clay is a regionally extensive fine grained lake bed deposit that underlies the

site at a depth of approximately 500 ft.

2. Tranquillity Site Soils

Soils in the Tranquillity Demonstration Project area consist of clays and loams, which

formed in alluvium, derived from igneous and sedimentary rock. Individual soil mapping

units in order of abundance in the project area include the Tranquility clay, Lillis Clay,

and the Lethent Silt Loam. The Tranquility mapping unit is the predominant soil type in

the study area and covers approximately 80% of the site, while the Lillis and Lethent

mapping units occur exclusively in Section 10 and cover the remainder of the site (Figure

37). The Tranquility clay is a very deep, poorly to moderately drained saline-sodic soil
Land Retirement Demonstration Program: Year 3

103

found on low-lying alluvial fans and flood plains with slopes between 0 and 1%. The

permeability of this soil is slow and the unit is suited to growing irrigated, salt-tolerant

crops, or for wildlife habitat (USDA 1996). Runoff is low, and the hazard of water

erosion is slight. The depth to the water table varies and is commonly highest during

irrigation applications in the winter and early spring. These soils generally require

intensive management to reduce salinity and maintain agricultural productivity. The

USDA took soil samples from a test pit located in the NW 1/4 of Section 16 at the site in

1992. The samples were analyzed in the laboratory for particle size, chemistry and

mineralogy. These soils consist predominantly of clay sized particles less than 0.002 mm

in diameter. The USDA reported that the clay fraction from 6 samples taken from the

test pit ranged from 48 to 52% of the total samples. Silt size particles (0.002-0.05 mm in

diameter) ranged from 36-37% of the total samples, and sand size particles made up from

11-16% of the total samples (USDA 1992). Total Selenium concentrations ranged from

0.5 to 1.1 ppm, and the Electrical Conductivity (EC) of soil water extracts ranged from

3.7 to 10.9 deciSiemens/meter (dS/m). These soils are highly plastic with Plasticity

Indices ranging from 23-52%. The predominant clay mineral is Montmorillonite, which

can take on water in the crystal lattice, resulting in high shrink-swell potential and

development of deep cracks at the soil surface upon drying.

The Lillis clay mapping unit covers about 10% of the study area in the eastern half of

Section 10 (Figure 37). These soils are very deep, poorly drained, saline-sodic soils

found typically on floodplains and basins. Permeability of the Lillis soil is extremely

slow, water infiltration rate is high, and when the soil is dry the surface cracks open. As

the soil becomes wet and the cracks close, the infiltration rate greatly decreases. Surface

water runoff is low and the hazard of water erosion is slight. The unit is used mainly for

wildlife habitat and recreation. The USDA took soil samples from a test pit located in the

SW 1/4 of Section 10 at the site in 1992. The samples were analyzed in the laboratory

for particle size, chemistry and mineralogy. These soils consist predominantly of clay

sized particles less than 0.002 mm in diameter. The USDA reported that the clay fraction

from nine samples taken from the test pit ranged from 59 to 66% of the total samples.

Silt-size particles (0.002-0.05 mm in diameter) ranged from 29-36% of the total samples,

and sand-size particles made up from 2-7% of the total samples (USDA 1992). Total

Selenium concentrations ranged from 0.3 to 0.7 ppm, and the EC of soil water extracts

ranged from 9.6 to 38.6 dS/m. These soils are highly plastic with Plasticity Indices

ranging from 33-61%. The predominant clay mineral is Montmorillonite, which can take

on water in the crystal lattice, resulting in high shrink, swell potential.

The Lethent silt loam mapping unit covers about 10% of the site in the north half of

Section 10 (Figure 37). These soils are deep, moderately well drained, saline-sodic soil

found on low lying alluvial fans and basin rims. Permeability of this soil is very slow,

runoff is slow, and the hazard of water erosion is slight (USDA 1996).
Land Retirement Demonstration Program: Year 3

104

Figure 37. U.S. Department of Agriculture soil mapping units, Tranquillity site.

a. Soil Sampling: Tranquillity Site

The objective of the soil monitoring program for the demonstration project is to detect

changes in levels of soil selenium, boron, and salinity that may result from land

retirement over the 5-year life of the demonstration project. Baseline soil sampling was

carried out by members of the Inter- Agency Land Retirement team during September

and October, 1999. Analyses of baseline soil data for the Tranquillity site can be found

in the calendar year 2000 annual report. This report is available on the USBR website at

http://www.mp.usbr.gov/regional/landret/2000annrpt/html/index.html or by request from

Mr. Robert May, the USBR Land Retirement Program Manager.

3. Weather: Tranquillity Site

Hourly precipitation, temperature, wind and relative humidity data are collected at the

California Irrigation Management Information System (CIMIS) weather station # 105,
Land Retirement Demonstration Program: Year 3

105

which is located 1.5 miles west of the demonstration project site at the Westlands Water

District (WWD) Tranquillity Field Office. The CIMIS station is operated and maintained

by the California Department of Water Resources (CDWR), and can be used to guide

crop irrigation scheduling and estimate consumptive water use for various crops. A total

of 8.9 inches of rainfall was recorded at the CIMIS station, with most of the rainfall

occurring between January and June (Table 46).

Table 46. Monthly CIMIS weather data and estimated barley crop water use at the

Tranquillity site for calendar Year 2001.

Month (2001)

Reference

evapotranspiration

(inches)

Barley crop

coefficient

Estimated

evapotranspiration

barley (inches)

Measured

precipitation

(inches)

January 1.46 0.3 0.44 1.69

February 1.98 1.18 2.34 1.06

March 4.00 1.18 4.72 0.40

April 5.30 1.18 6.25 0

May 9.69 0.40 3.88 2.26

June 9.84 0.20 1.97 0.78

July 8.46 Not applicable 0 0

August 8.26 Not applicable 0 0

September 6.39 Not applicable 0 0.02

October 4.56 Not applicable 0 0

November 1.98 Not applicable 0 1.39

December 1.01 Not applicable 0 1.28

Total 62.93 8.88

The following paragraph is an excerpt taken from the California Department of Water

Resources website (http://www.dpla.water.ca.gov/cimis/hq/etoexpl.txt) that defines the

concept of a reference evapotranspiration.

A daily reference evapotranspiration (ETo) is calculated from the CIMIS weather data by the

DWR. ETo is a term used to estimate the evapotranspiration rate of a reference crop expressed in

either inches or millimeters. The reference crop used for the CIMIS program is grass, which is

close clipped, actively growing, completely shading the soil, and well watered. ETo varies by

location, time, and weather conditions. The main factors that influence ETo include incoming

radiation (energy from the sun), outgoing radiation (sensible energy leaving the earth), the amount

of moisture in the air, air temperature, and wind speed (DWR 2000). The ET value can be used to

estimate the consumptive water demand of an agricultural crop. ETo can be estimated quite

accurately through the use of a "model" (a series of mathematical equations). The "model" that is

used in CIMIS is a version of Penman's equation modified by Pruitt/Doorenbos (Proceedings of

the International Round Table Conference on "Evapotranspiration", Budapest, Hungary 1977). It

also employs a wind function developed at UC Davis. The version used in CIMIS uses hourly

weather data to calculate daily ETo instead of daily weather data. Hourly averages of weather

data are used in the "model" to calculate an hourly ETo value. The 24 hourly ETo values for the

day (midnight to midnight) are summed to result in a daily ETo (DWR 2000). Hourly values of

net radiation, air temperature, wind speed and vapor pressure are the inputs used to calculate ETo.

Air temperature, wind speed, and vapor pressure are measured directly at each weather station.
Land Retirement Demonstration Program: Year 3

106

Hourly net radiation is estimated using a method developed by the University of California. This

method uses solar radiation, vapor pressure, air temperature, and a calculated monthly cloud

coefficient (DWR 2000).

Monthly barley crop consumptive water use exceeded precipitation at the site during the

calendar year 2001 in all months except January (-1.25 inches), November (-1.39 inches),

and December (-1.28 inches; Figure 38, Table 46). Due to dry soil conditions, the timing

of the rainfall, and evapotranspiration by plants most of the moisture from precipitation

probably either evaporated or was added to the soil moisture reservoir and thus did not

contribute toward deep percolation (recharge) to the shallow groundwater. Continued

declining groundwater level trends observed in the shallow monitor wells and sumps at

the site during calendar year 2001 support this inference.

Figure 38. Monthly precipitation and estimated barley crop consumptive water use for

calendar year 2001 at the Tranquillity site.

4. Irrigation: Tranquillity Site

A cover crop of barley was planted at the Tranquillity site to provide weed and dust

control and to isolate the experimental plots from each other. Approximately 367 acre

feet of water was applied to 960 acres of the barley crop in 2001, resulting in an average

of approximately 4.6 inches of water applied per acre. Water was applied to the 960

acres of barley using a hand moved sprinkler irrigation system in 12 hour sets during the

time period from March 15 to April 30, 2001. The barley crop consumptive water use

exceeded precipitation and applied irrigation water during the irrigation period (Table

47), thus it is unlikely that the irrigation application contributed to recharge to the

perched water table. Continued declining groundwater level trends observed in the

shallow monitor wells and sumps at the site during calendar year 2001 support this
Land Retirement Demonstration Program: Year 3

107

inference. Approximately 0.25 acre foot of water was also applied to a linear hedgerow

planting located on the west side of Section 23.

Table 47. Estimated barley crop consumptive water use as compared with precipitation

and applied irrigation water at the Tranquillity site.

Month

Estimated barley

ET (inches)

Precipitation

(inches)

Applied irrigation

(inches)

Irrigation deficit

(inches)

March 4.7 0.4 2.3 2.0

April 6.3 0 2.3 4.0

5. Hydrology and Surface Water Monitoring: Tranquillity Site

No surface water ponding was observed at the site during the calendar year 2001, and

thus no surface water samples were taken for chemical analysis. The natural drainage at

the site is to the east and northeast with ground surface elevations ranging from 169 ft

above mean sea level (AMSL), in the southwest corner of the site to about 162 ft AMSL

in the northeast portion of the site. The land surface in most of the study area has been

laser leveled to facilitate irrigation of row crops. There are no perennial surface water

bodies on the site. Shallow ephemeral surface water ponds may form on low lying

portions of the study area due to localized sheet-flow runoff during prolonged winter

storm events. Surface water courses within the area consist principally of irrigation

supply canals, and irrigation return flow ditches. Three irrigation tailwater ditches

traverse the site on Sections 15 and 16. Tailwater is irrigation water that does not

penetrate the soil, and runs off the irrigated cropland. Tailwater is usually collected in a

surface water pond and recirculated into the irrigation system. Fresno Slough, which is

located approximately 1 mile east of the study area, is the largest perennial surface water

body in the vicinity of the project. Fresno Slough receives flood flow releases from the

North Fork of the Kings River and serves as a storage reservoir for irrigation water

conveyed via the Delta Mendota Canal. Fresno Slough also occasionally receives flood

flows from Panoche Creek, which rises in the Coast Ranges to the west, and flows out

onto the Panoche Fan during winter storm events.

6. Groundwater Level Monitoring: Tranquillity Site

One of the primary objectives of the Demonstration Project is to measure the response of

the shallow water-table to land retirement. There are approximately 50 monitor wells and

three drain sumps in the project vicinity that are used to measure groundwater levels

beneath the site on a quarterly basis. The well and sump locations are shown on Figure

39. Existing wells constructed prior to the 1998 purchase of the demonstration project

lands were installed by Westlands Water District (WWD) and the U.S. Bureau of

Reclamation (USBR) for the primary purpose of measuring depths to groundwater

beneath drainage impacted lands in WWD. These existing wells are constructed of PVC

casing ranging in diameter from 0.75 to 4 inches and vary in depth from 3 to 86 ft below

the ground surface. These wells were installed using various construction techniques that
Land Retirement Demonstration Program: Year 3

108

range from jetting a short length of pipe into the ground to standard rotary drilling with

hydraulic drill rigs. During the summer of 1999, the USBR installed 15 additional wells

for the purpose of measuring groundwater levels and obtaining representative

groundwater samples for water quality analyses for the Land Retirement Demonstration.

The new wells were installed using a hollow stem auger drill rig and are constructed of 2-

inch PVC casing. Well construction diagrams for the new wells are on file at the USBR

office in Fresno, California. Well construction diagrams for the previously existing wells

are unavailable. There also are18 subsurface drain water collection sumps located in a

north to south alignment bisecting the northern half of Section 15 at the site. The sumps

are part of an experimental drainage system that was installed at the site during the

1960's. Subsurface tile drains lines were installed beneath the northwest quarter of

Section 15 at a depth of approximately 8 ft, with a drain spacing of approximately 150 ft.

The drain lines are approximately 6 inches in diameter and discharge to 3-foot diameter

concrete sumps that are open to the atmosphere. Water levels have been measured

quarterly in three of the drain sumps at the site (Figure 39).
Land Retirement Demonstration Program: Year 3

109

Figure 39. Monitor well and sump location map, Tranquillity site.

7. Groundwater Response to Land Retirement: Tranquillity

Site

Groundwater level data collected at the demonstration site as of this date supports the

conceptual model of a declining shallow groundwater table in response to land

retirement. Declining water level trends have been the norm for the wells monitoring the

shallow perched groundwater system at the site since the land was retired from irrigated

agriculture in August, 1998. A hydrograph is a commonly used method to graphically

display groundwater level trends observed in monitor wells. Hydrographs are time series

plots of water levels measured in monitor wells. A declining trend in groundwater levels

for the shallow perched groundwater system at the site is illustrated by the hydrographs

shown in Figure 40. The hydrographs represent water levels measured in three drain
Land Retirement Demonstration Program: Year 3

110

sumps (15C1, 15F2, 15K1) during the time period from July 1998 to July 2000. The

drain sumps are connected to tile drain lines that underlie the northwest quarter of Section

15, and are useful for measuring shallow groundwater trends in that portion of the site.

The drain sump locations are shown on Figure 39. All three of these sumps show an

overall declining trend in groundwater levels for the period of record. Total water-level

declines observed in sumps 15C1, 15F2, and 15K1 are 4.5, 3.0, and 2.4 ft, respectively.

Sumps 15C1 and 15 F2 were observed to be completely dry starting in January, 2000,

while sump 15C1 was observed to be completely dry starting in October, 2000. The

drain sumps have remained dry as of this date.

Figure 40. Hydrographs for three agricultural drain sumps at the Tranquillity site

showing a declining shallow groundwater trend

A declining water level trend has been observed in the southwest part of the site at

monitor wells 325 and 326. The hydrographs and locations for these wells are shown in

Figures 41 and 39, respectively. The total water-level declines observed in wells 325 and

326 for the period of record are 7.4 and 7.5 ft, respectively. A similar declining trend

was observed in wells 15M1 and 16A1 (Figure 42). The total water-level declines

observed in wells 15M1 and 16A1 were 5.2 and 6.1 ft, respectively.
Land Retirement Demonstration Program: Year 3

111

Figure 41. Hydrographs for monitor wells 325 and 326 at the Tranquillity site showing a

declining shallow groundwater trend.

Figure 42. Hydrographs for monitor wells 15M1 and 16A1 at the Tranquillity site

showing a declining shallow groundwater trend.

Synoptic depth to groundwater maps are another useful way to portray the decline of the

shallow water-table beneath the Tranquillity site. Figures 43-45 show the depth to

groundwater from the land surface as measured in monitor wells at the site in October,

1999, October, 2000, and October 2001, respectively. The measured depth to

groundwater data was contoured using Environmental Systems Research Institute (ESRI)

ArcView Spatial Analyst software to produce the maps. During October, 1999
Land Retirement Demonstration Program: Year 3

112

approximately 30% (600 acres) of the site was underlain by a water-table within 7 ft of

the land surface. During October, 2000 approximately 3% of the site (55 acres) was

underlain by a water-table within 7 ft of the land surface. In October, 2001 the area of

the site underlain by a water-table within 7 ft of the land surface decreased to less than

2% of the site (34 acres). Another aspect of the site hydrogeology shown by the synoptic

maps is the fact that the site can be divided into two distinct areas based on the depth to

groundwater observations. The depth to the water-table north of Adams Avenue (Section

10) is significantly greater than that observed south of Adams Avenue. The differences

can be attributed to two factors. This area of the site (Section 10) has been retired from

irrigated agriculture since 1994, and has not received significant application of irrigation

water (groundwater recharge) since that time. Section 10 is also underlain by more

permeable Sierran sand deposits, which allow more rapid percolation of applied irrigation

water.
Land Retirement Demonstration Program: Year 3

113

Figure 43. Depth to shallow groundwater, October, 1999. The project area underlain by

shallow groundwater within 7 ft of the land surface is approximately 600 acres.
Land Retirement Demonstration Program: Year 3

114

Figure 44. Depth to shallow groundwater, October, 2000. The project area underlain by

shallow groundwater within 7 ft of the land surface is approximately 55 acres.
Land Retirement Demonstration Program: Year 3

115

Figure 45. Depth to shallow groundwater, October, 2001. The project area underlain by

shallow groundwater within 7 ft of the land surface is approximately 34 acres.

The combinations of dry climatic conditions and greatly reduced irrigation applications

associated with land retirement have resulted in significant shallow water-table declines

at the Tranquillity demonstration site. Nearly all the monitor wells are showing a
Land Retirement Demonstration Program: Year 3

116

declining water level trend over time. The average drop in the shallow water table

measured in 10 wells at the site during the first 2 years of monitoring is approximately 4

ft (Table 48). To conclusively demonstrate the cause and effect relationship between the

declining shallow groundwater levels observed on site and land retirement, comparison

with background or reference wells is warranted. Ideal background wells would be

located in the project vicinity, with similar soils and geology, but in an area with active

ongoing irrigation. An effort will be made to obtain data from appropriate offsite

"background" wells for comparison with observed demonstration project groundwater

levels.

Table 48. Groundwater level decline observed in ten wells at the Tranquillity site for the

time period from August, 1999 to October, 2001.

Well Water level decline (feet)

15P1 5.6

15L1 1.0

15M1 4.8

15F1 3.3

16G1 3.7

16Q1 4.4

16A1 5.6

16B1 5.8

15N1 4.9

15C1 2.7

Minimum 1.0

Maximum 5.8

Average 4.1

8. Groundwater Quality Monitoring: Tranquillity Site

The purposes for selenium groundwater-quality monitoring at the site are to establish

baseline conditions that can be used as a basis for comparison for change-detection

analyses, and to collect data that can be used to evaluate exposure risk to wildlife via the

groundwater pathway. Baseline groundwater samples were taken on a quarterly basis

during year 1 of monitoring at the Tranquillity site. The baseline groundwater quality

samples were taken in October 1999 and February, May, and July 2000. Annual

groundwater sampling began at Tranquillity in May 2001, and will continue for the 5-

year duration of the project. The springtime sampling was chosen to coincide with the

seasonal high water table in the region. The annual, groundwater-quality data will be

compared to the baseline data set to evaluate changes in groundwater quality. Unfiltered

groundwater samples were taken from 12 wells and two drain sumps to assess baseline

groundwater quality at the site. Standard operating procedures for groundwater sampling

used by the Mid-Pacific Region of the USBR and those outlined in the Quality Assurance
Land Retirement Demonstration Program: Year 3

117

Project Plan for the Land Retirement Demonstration Project (CH2M Hill 1999) were

employed to obtain groundwater samples.

Unfiltered groundwater samples were analyzed for major ions (calcium, magnesium,

potassium, sodium, chloride, sulfate, total alkalinity), trace elements (selenium, boron,

iron, manganese) and isotopes (H-2, O-18 and H-3). Specific conductance (electrical

conductivity), pH, temperature, and turbidity of groundwater samples were measured in

the field at the time of sampling. Flourometric analyses of groundwater samples for

selenium were performed by Olsen Biochemistry Laboratories, South Dakota State

University. Analyses for isotopes (H-2, O-18) were performed by the USGS Water

Resources Division laboratory in Reston, Virginia. Analyses for tritium (H-3) were

performed by the USGS Water Resources Division laboratory in Menlo Park, California.

All other analyses were performed by Caltest Analytical Laboratory in Napa, California.

The Quality Assurance Project Plan (QAPP) for the Land Retirement Demonstration

Project describes in detail the analytical procedures and quality assurance measures taken

to ensure groundwater data quality (CH2M Hill 1999).

a. Groundwater Salinity: Tranquillity Site

A general indication of the total dissolved ionic constituents in the groundwater can be

obtained by determining the capability of a groundwater sample to conduct an applied

electrical current. This property is reported as specific conductance (also electrical

conductivity, EC), and is expressed in terms of the conductivity of a cube of water 1

square centimeter on a side. EC is expressed in units of microSiemens/cm (μS/cm).

Baseline EC data for the groundwater samples collected during the first year of

monitoring are presented in Tables 37 and 38. The shallow, perched groundwater is

extremely saline in nature. Salinity in the shallow groundwater and drain sump samples,

expressed as EC, ranged from 11,500 to 76,980 μS/cm, with a median value of 43,925

μS/cm. By comparison, drinking water typically is less than 750 μS/cm, irrigation water

is less than 1,250 μS/cm, and seawater is about 50,000 μS/cm. The groundwater samples

obtained from the underlying semi-confined aquifer is much less saline. Salinity in the

groundwater samples obtained from the deep wells (> 50 ft deep), expressed as EC

ranged from 5,630 to 18,580 μS/cm, with a median value of 7,675 μS/cm.

The extreme salinity of the shallow groundwater at the site is a result of the irrigation of

saline soils. Naturally occurring salts have been leached from the soil profile under

irrigated conditions. Salts also have been transported to the site in the applied irrigation

water. Direct evaporation from the shallow water table and transpiration of applied water

by crops has concentrated salts in the shallow groundwater, resulting in the high EC

values observed in the shallow groundwater samples.

b. Groundwater Major Ion Chemistry—Tranquillity Site

Baseline major ion chemistry for the groundwater samples collected during year 1 of

monitoring are presented in Tables 37 and 38 The groundwater comprising the shallow,

perched water, and in the underlying semi-confined aquifer is best described as a sodium

sulfate type of water. Sodium is the dominant major cation found in the shallow
Land Retirement Demonstration Program: Year 3

118

groundwater samples, with sodium concentrations ranging from 2,300 to 25,000 mg/l,

and a median concentration of 13,000 mg/l. Sodium is also the dominant major cation

found in groundwater samples taken from the deep wells, with concentrations ranging

from 760 to 3,800 mg/l, and a median concentration of 1,100 mg/l. Sulfate is the

dominant major anion found in both the shallow, perched groundwater and in the

underlying semi-confined groundwater at the site.

Table 49. Groundwater quality data for shallow wells at the Tranquillity site - major ions

and field parameters.

Statistic Minimum 25th percentile Median 75th percentile Maximum Mean

Number of Samples 44 44 44 44 44 44

EC(field) (μS/cm) 11500 32620 43260 52350 76980 41987

pH (field) 6.74 7.54 7.78 7.9 8.37 7.73

Calcium (mg/l) 250 400 420 450 500 417

Magnesium (mg/l) 42 250 525 663 1300 515

Sodium (mg/l) 2300 8725 13000 16500 25000 13009

Potassium (mg/l) 7 20 30 42 94 32

Total Alkalinity (mg/l) 150 260 330 423 610 351

Chloride (mg/l) 380 1150 2700 3200 4100 2332

Sulfate (mg/l) 4300 24500 31000 62000 26330

Table 50. Groundwater quality data for deep wells at the Tranquillity site - major ions

and field parameters.

Statistic Minimum 25th percentile Median 75th percentile Maximum Mean

Number of Samples 12 12 12 12 12 12

EC(field) (μS/cm) 5630 6763 7675 17315 18580 10633

pH (field) 6.82 7.13 7.21 7.28 7.46 7.21

Calcium (mg/l) 280 300 320 360 390 327

Magnesium (mg/l) 280 300 310 328 350 315

Sodium (mg/l) 760 823 1100 2425 3800 1714

Potassium (mg/l) 6 9 13 14 20 12

Total Alkalinity (mg/l) 200 250 270 329 340 277

Chloride (mg/l) 300 410 540 1700 1900 924

Sulfate (mg/l) 2100 2750 3100 5525 7300 4067
Land Retirement Demonstration Program: Year 3

119

Sulfate concentrations found in groundwater samples from the shallow wells (< 50 ft

deep) ranged from 4,300 to 62,000 mg/l, with a median concentration of 24,500 mg/l.

Sulfate concentrations in groundwater samples from the deep wells (greater than 50 ft

deep) completed in the semi-confined aquifer ranged from 2,100 to 7,300 mg/l, with a

median concentration of 3,100 mg/l (Figure 46).

Figure 46. Comparison of dominant major ion concentrations and electrical conductivity

for groundwater samples from shallow and deep wells.

High sodium and sulfate concentrations in the groundwater on the west side of the San

Joaquin Valley result from weathering of sulfate rich rocks in the adjacent Coast Ranges.

Davis (1961) hypothesized that the sulfate in groundwater in the study region originates

from the oxidation of organic marine shales containing reduced iron sulfide minerals.

Presser et al. (1990) have reported oxidation of iron sulfide minerals for west-side

streams in the study vicinity. Another probable source of sulfate in the shallow

groundwater is gypsum (calcium sulfate) that has historically been applied to soils by

farmers in the region as a method of salinity management.

c. Trace Elements in Groundwater - Tranquillity Site

The trace elements of concern monitored for this study include selenium and boron.

High concentrations of selenium and boron in the shallow groundwater are of concern

due to potential toxicity to wildlife and plants. Iron and manganese concentrations were

also monitored because they provide insight into geochemical conditions in the

groundwater system. A summary of baseline trace element data for the first year of

groundwater monitoring is presented below.
Land Retirement Demonstration Program: Year 3

120

Table 51. Groundwater quality data for shallow wells at the Tranquillity site - trace

elements and tritium.

Statistic Minimum 25th

percentile Median 75thpercentile Maximum Mean

Number of Samples 44 44 44 44 44 44

Boron (mg/l) 10 26 46 55 81 42

Iron (mg/l) 0.1 0.8 2.1 15 160 19.4

Manganese (mg/l) 0.008 0.11 0.23 1.1 3.9 0.757

Selenium (mg/l) 0.005 0.195 1.28 3.812 5.39 2.095

Tritium (TU) 0 0.9 2.4 3.7 6 2.3

Table 52. Groundwater quality data for deep wells at the Tranquillity site - trace

elements and tritium.

Statistic Minimum 25th

percentile Median 75thpercentile Maximum Mean

Number of Samples 12 12 12 12 12 12

Boron (mg/l) 2.5 2.8 3.2 6.6 8.3 4.4

Iron (mg/l) 0.3 0.6 1.2 1.3 1.6 1

Manganese (mg/l) 0.25 0.318 1.75 2.5 4.3 1.718

Selenium (mg/l) < 0.0004 0.0005 1.84 1.91 1.95 1.0873

Tritium (TU) 0 0.4 10.1 11.6 14 7.5

d. Selenium in Groundwater - Tranquillity Site

Selenium concentrations measured in the shallow groundwater wells and sumps (less

than 50 feet deep) at the site during the first year of monitoring show considerable spatial

variation. In general, selenium concentrations in the shallow groundwater system are

high, ranging from 5 to 5,390 μg/l (0.005 to 5.390 mg/l), with a median concentration of

1,280 μg/l (1.280 mg/l). By comparison, the USEPA water-quality criteria for long-term

exposure in aquatic environments is 5 μg/l (USEPA 1988). It becomes clear why the

conceptual model of a declining shallow water-table is an essential element of land

retirement in light of the extremely high concentrations of selenium observed in the

shallow groundwater. If these waters were exposed at the land surface, wildlife could be

exposed to potentially toxic conditions. Deverel and Millard (1988) concluded that the

main factors affecting selenium concentrations in the shallow groundwater of the western

San Joaquin Valley are the degree of groundwater salinity and the geologic source of the

alluvial soils.
Land Retirement Demonstration Program: Year 3

121

Selenium concentrations measured in the deep wells (> 50 ft deep) at the site also show

considerable spatial variation. Selenium concentrations found in well 15M3 (69 ft deep),

ranged from 1,840 to 1,950 μg/L during the first year of monitoring, while selenium

concentrations found in Wells 15C3 and 10G3 (83 and 75 ft deep, respectively) range

from the analytical limit of detection (less than 0.0004) to 0.0005 μg/l. The extreme

variation in selenium concentration seen in the deep wells may be explained due to

differing geochemical conditions found in Coast Range deposits and the Sierran sands

underlying the site. Well 15M3 is perforated in coast range sediments, while wells 15C3

and 10G3 are perforated in sediments derived from the Sierra Nevada Range. Dubrovsky

et al. (1993) noted high concentrations of selenium in shallow groundwater in Coast

Ranges sediments, and low concentrations in underlying Sierra Nevada sediments in

previous groundwater quality investigations in the western San Joaquin Valley. The

authors hypothesized that the absence of selenium in groundwater from wells screened in

the Sierra Nevada deposits may be due to a redox (chemical reduction or oxidation)

process. Selenium can exist in four valence states; -2, 0, +4, and +6. The +6 and +4

valences occur as the oxyanions selenate (Se O4

2-) and selenite (SeO32-) under alkaline,

oxidizing conditions. Selenate is the most oxidized form of selenium, is relatively mobile

in aqueous environments, and does not associate with solid phase materials (Leckie et al.

1980, Frost and Griffin 1977, and Hingston et al. 1974). Deverel and Fujii (1988)

reported that the selenium in soil solutions and shallow groundwater in the western San

Joaquin Valley is in the selenate form, and a very small percentage of soil selenium is in

the absorbed phase. Although no attempt has been made to speciate selenium in

groundwater samples from the Land Retirement Demonstration Project, the selenium

found in the shallow groundwater at the site probably occurs predominantly as selenate.

Under more reduced conditions, such as those found in the underlying Sierra Nevada

deposits in the northern part of the site, selenium can exist as elemental selenium (zero

valence) and selenide (Se2-). The solubility of selenate minerals generally is high

(Elrashadi et al. 1987), and there are no apparent solubility constraints on selenate in

shallow groundwater in the western San Joaquin Valley, even in groundwater saturated

with respect to sulfate minerals (Deverel and Gallanthine, 1989). Consequently, selenate

tends to behave conservatively in oxidizing groundwater. The mobility of selenite in

groundwater is severely constrained by adsorption onto a variety of mineral surfaces

(Balistrieri and Chao 1987, Neal et al.1987, Goldberg and Glanbig 1988) The solubilities

of the reduced forms of selenium (elemental selenium and selenide) are extremely low

(Elrashadi et al. 1987). Field and laboratory studies of selenium contamination at

Kesterson Reservoir demonstrated selenium removal by reduction of selenate to less

mobile forms (Lawrence Berkeley Laboratory 1987, White et al. 1988, Weres et al.

1989). Similar geochemical processes may be responsible for the extremely low

selenium concentrations observed in Wells 15C3 and 10G3 at the Tranquillity site.

Dubrovsky et al. (1993) noted that selenium concentrations in groundwater decreased

rapidly at the same depth at which manganese concentrations increase at a research site

located in the vicinity of the Tranquillity site in the western San Joaquin Valley. The

authors concluded that the decrease in selenium is due to a process that occurs under

reducing conditions. High concentrations of dissolved iron and manganese in

groundwater can indicate geochemically reducing conditions. A similar trend is observed

at the land retirement study site when ratios of selenium to manganese concentrations are
Land Retirement Demonstration Program: Year 3

122

plotted verses well depth. The selenium/manganese ratios are generally high in the

shallow wells and extremely low in the deep wells, especially those perforated in the

Sierran deposits (Figure 47). This supports the conceptual model that oxidizing

conditions are prevalent in the shallow groundwater, and that reducing conditions are

prevalent in the deep groundwater found in the Sierran deposits. Reducing geochemical

conditions in the Sierran deposits probably play a significant role in the extremely low

selenium concentrations observed in wells 15C3 and 10G3.

Figure 47. Ratio of Selenium to Manganese (Se/Mn) concentration in groundwater

samples plotted verses well depth. The Se/Mn ratio shows a decreasing trend with depth

indicating oxidizing geochemical conditions in the shallow wells and reducing conditions

in the deep wells.

e. Selenium Trends in Shallow Groundwater—Tranquillity Site

The US Fish and Wildlife Service (USFWS) established performance standards for

retired lands in the Recovery Plan for Upland Species of the San Joaquin Valley (USFWS

1998). The performance standard for selenium in groundwater specifies that the

selenium concentrations should not show an increasing trend over 5 years of monitoring.

The high spatial variability of the selenium data observed for the groundwater at the

Tranquillity site precludes the comparison of mean or median values for the entire set of

monitor wells due to the limited sample size. Given the variability of the baseline
Land Retirement Demonstration Program: Year 3

123

selenium data, over 200 wells would be required to accurately estimate the population

mean concentration of selenium in the shallow groundwater at a given time. A time

series analysis at each monitor well will be used to establish trends for selenium

concentrations in the groundwater at the site. To establish reliable time series trends,

autocorrelation or autoregression analyses will be performed on the time series data from

each well. Both of these techniques require relatively long-term data records based on

evenly spaced data. There currently are not enough data to draw any statistically

meaningful conclusions regarding the trend of selenium concentrations in the

groundwater. The current data consist of four quarterly samples obtained during year 1

and one sample obtained during year 2 of monitoring. Preliminary analysis of time series

data from 11 wells at the site show a decreasing trend for 4 wells and an increasing trend

for 7 wells. Only the increasing trends observed at wells 16J1 and 16Q1 are significant at

the 95% confidence level (Table 53). The additional annual data collection over the life

of the 5-year demonstration project should be adequate to establish definitive time series

trends for selenium in the groundwater at the site.

Table 53. Preliminary analysis of Selenium trends in groundwater at the Tranquillity

site.

Well Preliminary trend Correlation coefficient (r2)

Significance at 95%

confidence

15M1 Downward .57 Not significant

15P1 Upward .08 Not significant

15M3 Downward .02 Not significant

15B3 Upward .39 Not significant

16J1 Upward .86 Significant

15F1 Upward .01 Not significant

16Q1 Upward .71 Significant

16G1 Upward .47 Not significant

16A1 Downward .29 Not significant

16B1 Upward .21 Not significant

10M1 Downward .40 Not significant

f. Boron in Groundwater—Tranquillity Site

The presence of high concentrations of boron in the shallow groundwater are of concern

due to potential toxicity to plants and wildlife. Boron concentrations in the shallow

groundwater at the site are extremely high. The boron concentrations measured in the

shallow wells range from 10 to 81 mg/l, with a median value of 45.5 mg/l (Table 51). No

water-quality criteria for boron exist for aquatic life or human health. There is an

irrigation water criterion of 750 micrograms/liter (μg/l) of boron sensitive crops (US EPA

1986). Perry et al. (1994) have proposed a toxicity threshold in water for crops and

aquatic plants of 10 mg/l. Deverel and Millard (1988) noted that boron is geochemically

mobile and present as oxyanions in oxidized, alkaline environments such as the western

San Joaquin Valley shallow groundwater. The authors also reported high correlation
Land Retirement Demonstration Program: Year 3

124

between log transformed boron and specific conductance data for shallow groundwater in

the western San Joaquin Valley. Boron concentrations observed in the deep wells at the

site are an order of magnitude lower than those in the shallow wells. Boron

concentrations measured in the deep wells during year 1 of monitoring range from 2.5 to

8.3 mg/l, with a median concentration of 3.2 mg/l (Table 52). The large difference in

boron concentration between the shallow and deep groundwater at the site may be due to

adsorption onto soil surfaces or differing geochemical conditions between the shallow

and deep groundwater systems. Adsorption of boron on soil particles can affect and limit

its solubility (Keren and Bingham 1985). Fujii and Swain (1995) concluded that the

relatively conservative behavior of boron observed in shallow groundwater in the San

Joaquin Valley probably reflects the presence of high concentrations of competing

constituents for adsorption sites.

g. Origin and Isotopic Composition of Groundwater - Tranquillity Site

Groundwater samples were analyzed for tritium and stable isotope ratios of oxygen and

hydrogen during the first 3 years of monitoring. Tritium and stable isotope data are

currently available for the first 2 years of monitoring. A summary of the tritium data is

presented in Tables 39 and 40. The oxygen and hydrogen isotope data can provide

insight into the evaporation history of the water, while the tritium data can be used to

develop an understanding of the age and origin of the groundwater at the site.

h. Groundwater Age - Tranquillity Site

The levels of tritium, a radioactive isotope of hydrogen with a half-life of 12.43 years,

rose in the environment during the 1950's and 1960's because of atmospheric detonation

of nuclear weapons. Tritium concentrations can be used to develop an understanding of

the origin and history of water samples. Tritium concentrations in water samples are

reported in tritium units (TU). Prior to 1952, precipitation contained < 5 TU. Due to

radioactive decay, groundwater derived from precipitation before 1952 now has < 0.5

TU. Groundwater derived from precipitation recharged since 1952, including canal water

used as irrigation since 1968, commonly has a tritium concentration exceeding 10 TU.

Groundwater with a tritium concentration of < 1.6 TU either has recharged prior to 1952

or may have originated as post-1952 irrigation water from deep wells. This large contrast

in tritium concentration allows comparison of older groundwater, much of which was

recharged prior to agricultural development, to young water recharged since 1952 and

derived from irrigation (Dubrovsky et al. 1993).

The tritium data from the shallow wells indicate that the shallow, perched groundwater

consist of a mixture of water recharged before and after 1952. Tritium concentrations of

the shallow groundwater samples range from 0 to 6 Tritium Units (TU), with a median

concentration of 2.4 TU. Low tritium concentrations (< 1 TU) observed in wells 16Q1

and 16F1 may indicate recharge from irrigation water that was pumped from deep

production wells completed in the sub-Corcoran aquifer. The tritium data from the deep

wells (Well 15M3 and 16B3) completed in coastal range deposits indicate that the

groundwater was recharged before 1952. Tritium concentrations observed in these two

wells ranged from 0 to 0.5 TU, with a median concentration of 0.1 TU. The tritium data

from the deep wells completed in Sierra Nevada sediments indicate that the groundwater
Land Retirement Demonstration Program: Year 3

125

has been recharged since 1952. Tritium concentrations found in wells 15C3 and 10G3

range from 9.6 to 14.0 TU, with a median concentration of 10.5 TU.

i. Evaporative concentration of shallow groundwater—Tranquillity Site

In areas where the water-table is shallow in the western San Joaquin Valley, particularly

at depths less than 1.5 meters below land surface, evaporative concentration of dissolved

solids in groundwater can increase salinity and selenium concentrations far above the

levels resulting from leaching of soil salts by irrigation (Deverell and Fujii 1988). Under

irrigated conditions loss of water by evapotranspiration tends to concentrate salts in

groundwater rather than soil because the salts are regularly flushed downward by

percolating irrigation water and net groundwater movement is generally downward

(Dubrovsky et al. 1993).

Hydrogen and oxygen isotope data from shallow groundwater samples at the Tranquillity

site show that groundwater salinity is primarily a result of evaporation and

evapotranspiration of the shallow groundwater. The evaporation process adds kinetic

separation to the hydrogen-2 (deuterium) and oxygen-18 species causing increased

enrichment in the O-18 species (Gat and Gonfiantini 1981). This results in a plot of the

delta deuterium (D) verses delta O-18 that has a smaller slope than the meteoric water line.

The comparison of delta D and delta O-18 shown in Figure 48 illustrates the evaporation

that has taken place in the shallow groundwater at the site. Similar evaporative trend

lines have been reported by Deverell and Fujii (1988) and Presser and Barnes (1984) for

shallow groundwater in the western San Joaquin Valley.

Figure 48. Plot of stable isotope data for groundwater samples from the Tranquillity site

indicating the shallow groundwater has undergone significant evaporation.
Land Retirement Demonstration Program: Year 3

126

B. Atwell Island Site

1. Atwell Island Site Geology

The Atwell Island demonstration site lies on the southwestern margin of the Tulare Lake

Bed, which is the dominant geologic feature in the study area. The site is underlain by

lakebed and marsh deposits consisting primarily of clay and silt with some sand with a

thickness in excess of 3,600 ft (Page 1986). The Corcoran Clay member of the Tulare

Formation is a regionally extensive fine-grained lakebed deposit that underlies the Atwell

Island site at a depth of approximately 900 ft below the land surface. A relict sand dune

deposit consisting of fine-grained wind blown sand from the former shoreline of the

Tulare lakebed traverses the western boundary of the site from southwest to northeast.

2. Atwell Island Site Soils

Soils in the Atwell Island study area consist of silt and sand loams that are formed in

alluvium derived from igneous and sedimentary rocks. Individual soil mapping units

found in the study area in the order of abundance include the Posochanet silt loam,

Nahrumb silt loam, the Westcamp silt loam, Excelsior find sandy loam, and Lethent fine

sandy loam (Figure 49). The Posochanet soils occur primarily in the central portion of

the site and cover about 30% of the total study area. These soils are saline, alkaline, very

deep, moderately well drained with slow permeability. Salinity ranges from 4 to 8 dS/m

in the upper portion and 4 to 30 dS/m in the lower portion. Surface runoff is generally

slow, with a low hazard of water erosion. Nahrumb silt loam occurs on basin rims and

consists of mixed alluvium from granitic rocks. Nahrumb soils cover about 30% of the

total surface area in the southeast part of the site. These soils are very deep, somewhat

poorly drained, with very slow permeability. Salinity ranges from 1-16 dS/m in the upper

part to 8-30 dS/m in the lower part. Surface runoff is very slow with low surface erosion

hazard. Westcamp silt loam soils cover the northwest corner of the study area. The

Westcamp soils are saline, alkaline soils that have a perched water table. These soils are

very deep, somewhat poorly drained, with very slow permeability. A transient high water

table occurs at a depth of 4-6 ft. Salinity ranges from about 2-16 dS/m. Excelsior fine

sandy loam soils are found on the sand ridge that traverses the site from northeast to

southwest. The sand ridge covers about 15% of the total study area. The Excelsior soils

are very deep, somewhat excessively drained alkaline soils. Permeability of the sand

ridge soil is moderately rapid, runoff is very slow and hazard of water erosion is slight,

however the potential for wind erosion is high under sparsely vegetated conditions.

Salinity ranges from 0-8 dS/m in the upper part and 2-16 dS/m in the lower part. The

Lethent fine sandy loam occurs in a small area in the southwest part of the study area.

This soil is saline, alkaline, very deep, and moderately well drained. Permeability is very

slow and the hazard of water erosion is slight.

a. Soil Sampling: Atwell Island Site

Baseline soil sampling will be conducted at the Atwell Island site during spring of 2002.

Sixteen sites will be sampled within each experimental block. Each site will be located at
Land Retirement Demonstration Program: Year 3

127

the approximate center of the 2-acre plots (Figure 49). Three soil samples will be

collected from each site. A 0-12 inch sample consisting of a four increment composite

soil samples collected within a 2-meter radius of the central boring. A single soil sample

will be collected from the 12-30-inch depth interval. This sample represents the active

root zone of irrigated soils. A single soil sample will also be collected from the 30-60-

inch substrata zone. This zone represents the lower root zone just above the vadose zone.

All soil material will be sampled in the 12-30 and 30-60-inch samples. Sampling in this

manner will result in 48 soil samples collected on each 160 acre block. Two field

replicate (QC) samples will be collected from each quarter section. Field replicate

samples will be done using the fractional shoveling method. All sample sites will be

located and georeferenced using a GPS receiver set on the North American 1927 datum.

Soil samples will be analyzed for total and water soluble selenium, sulfate, chloride,

electrical conductivity, and moisture. All surface soil samples will be analyzed for boron,

magnesium, potassium, sodium, carbonate, and nitrate. The Quality Assurance Project

Plan (QAPP) for the Land Retirement Demonstration Project describes in detail the

analytical procedures and quality assurance measures taken to ensure soil data quality

(CH2M Hill 1999). The soils analyses will be performed by the U.S. Geological Survey

and the U.S. Bureau of Reclamation analytical laboratories in Denver, Colorado.

Figure 49. U.S. Department of Agriculture soil mapping units and soil sample locations

at the Atwell Island site.
Land Retirement Demonstration Program: Year 3

128

3. Weather: Atwell Island Site

Hourly precipitation, temperature, wind and relative humidity data are collected at the

California Irrigation Management Information System (CIMIS) weather station #21,

which is located approximately 18 miles west of the demonstration project site. The

CIMIS station is operated and maintained by the CDWR, and can be used to guide crop

irrigation scheduling and estimate consumptive water use for various crops. A total of

7.99 inches of rainfall was recorded at the CIMIS station, with most of the rainfall

occurring between January, April, and October-December.

4. Irrigation: Atwell Island Site

A cover crop of barley was planted on the three habitat restoration study blocks at the

Atwell Island site to provide weed and dust control and to equilibrate the soil conditions

on the study plots prior to installation of the experimental treatments. Accordingly, both

the buffer areas and the study plots were planted in barley. Approximately 164 acre-feet

of water was applied to 480 acres, resulting in an application rate of approximately 4.1

inches of water per acre. However, water was not applied in equal amounts to each study

block. On block 1 (see Figure 49), 64.7 acre-feet of water was applied by flood irrigation

during the time period from 24-31 March 2001. On block 2, 48.8 acre-feet was applied

by sprinkler irrigation during the time period from 30 March through 5 April, 2001 and

on block 3, 50.7 acre-feet of water was applied using sprinkler irrigation.

The largest volume of irrigation water applied at the site during calendar year 2001 was

from ongoing farming operations. Farming operations continued on approximately 2,800

acres of the Atwell Island site as negotiations for land acquisition with the current

landowners proceeded. Irrigation applications on these lands are currently scheduled

based on a calendar or rotational approach. Metered pumping volumes for applied

irrigation water are not available from the current landowners. Typical irrigation

applications consist of gravity flow (flood irrigation) of about 6 acre-inches per acre. An

estimate of applied water and deep percolation (groundwater recharge) for irrigated lands

within the demonstration project boundary at the Atwell Island site is shown in Table 54

(Smith 2001).
Land Retirement Demonstration Program: Year 3

129

Table 54. Estimated 2001 net crop water requirement and deep percolation losses at the

Atwell Island site.

Crop Acreage

Total crop water

requirement

(acre-feet)

Irrigation water

application

requirement

(acre-feet)

Estimated deep

percolation

(acre-feet)

Alfalfa 1,142 4,568 7,028 2,460

Barley 160 211 325 114

Oats 1,001 821 1,263 442

Safflower 490 1,269 1,952 683

Total 2,793 6,869 10,568 3,699

5. Hydrology and Surface Water Monitoring: Atwell Island

Site

Monitoring of surface water at the Atwell Island site will commence in calendar year

2002. The natural drainage in the study area is to the north-northwest with ground

surface elevations ranging from about 205 ft AMSL, in the southeast portion of the site to

about 215 ft AMSL in the northeastern portion of the site. A pronounced sand ridge

traverses the northern boundary of the site in a northeasterly direction. The sand ridge

was formed from windblown sand deposited along the southern shore of the Tulare Lake

bed. Surface water courses within the study area consist primarily of irrigation supply

canals and irrigation return flow ditches, although the site has an artificially constructed

20-acre wetland that is filled from surface irrigation water supplies. Shallow ephemeral

surface water ponds may form on low lying portions of the site due to localized sheet

flow run-off during prolonged winter storm events. The surrounding areas in the vicinity

of the Atwell Island site receive periodic unregulated winter storm flows from Deer

Creek, Poso Creek, and the White River. The study area parcels under consideration are

generally not subject to long term flooding due to their higher topographic position with

respect to the adjacent lower lying lands.

6. Groundwater Level Monitoring: Atwell Island Site

There are approximately 20 monitor wells in the project vicinity that will be used to

measure groundwater levels beneath the site on a quarterly basis. The well locations are

shown on Figure 50 . Existing wells constructed prior to the purchase of the

demonstration project lands were installed by the U.S. Geological Survey, the CDWR

and the USBR to assess groundwater conditions in the Tulare basin. These existing wells

are constructed of PVC casing ranging in diameter from 0.75 to 3 inches and vary in

depth from 20 to 190 ft below the ground surface. These wells were installed using

various construction techniques that range from jetting a short length of pipe into the

ground to standard rotary drilling with hydraulic drill rigs. During the fall of 1999, the

USBR installed 17 new monitoring wells for the purpose of measuring groundwater
Land Retirement Demonstration Program: Year 3

130

levels and obtaining representative groundwater samples for water quality analyses for

the Land Retirement Demonstration Project. The new wells range in depth from 15 to 60

ft below land surface and were installed using a hollow stem auger drill rig and are

constructed of 2 inch PVC casing. Well construction diagrams for the new wells are on

file in the USBR offices in Fresno and Sacramento. Well construction information for

the USGS wells are published by Beard et al. (1994), Fujii and Swain (1995) and Swain

and Duell (1993).

Figure 50. Monitor well locations at the Atwell Island site.

7. Groundwater Levels: Atwell Island Site

Calendar year 2002 will serve as the baseline year for establishing groundwater levels

and groundwater quality at the Atwell Island site. Groundwater levels measured in 20

wells during January 2002 confirm the presence of shallow, perched water table

conditions at the Atwell Island site. Groundwater levels observed during January 2002 in

the shallow groundwater system range from 4.3 to 14.8 ft below land surface. In general,

the water-table is highest (nearest the land surface) in the northeast corner of the site and

becomes deeper in the southeast portion of the site. These observations are consistent

with those of Beard et al. (1994) and the USBR (1982). Water levels will be measured

quarterly in the monitor wells over the life of the demonstration project in order to track

the water-table response to land retirement. An attempt will be made to identify and

collect water level data from appropriate reference wells in the project vicinity.
Land Retirement Demonstration Program: Year 3

131

8. Groundwater Quality Monitoring: Atwell Island Site

Baseline groundwater quality samples will be taken on a quarterly basis during the first

year of monitoring at the Atwell Island site. The first round of groundwater samples

were taken from 20 wells at the Atwell Island site in January 2002. The same sampling

and analysis protocols that were used at the Tranquillity site will be used on groundwater

samples at the Atwell Island site.
Land Retirement Demonstration Program: Year 3

132

V. TOURS, PRESENTATIONS,

CONFERENCES, AND WORKSHOPS

The Land Retirement Team gave an annual site tour to interested agency personnel and

private parties on 18 April 2001.

In January 2001, a presentation was given at The Wildlife Society's Western Section

annual conference in Sacramento, CA. The title of the presentation was "Restoration of

native plant and animal communities on retired agricultural lands". Two presentations

were given at the Society for Ecological Restoration, California Chapter at a conference

held in San Diego, CA. on 1-2 November 2001. The title of the presentations were

"Habitat restoration on retired agricultural lands in the San Joaquin Valley, Part I:

Successes and failures of native plant restoration" and "Habitat restoration on retired

agricultural lands in the San Joaquin Valley, Part II: Responses of wildlife to restoration".

A 1-hour long lecture was given in May 2001 to biology students and faculty at

California State University, Stanislaus as part of a symposium series. The LRT also

presented a PowerPoint presentation of the Land Retirement Demonstration project to the

Westlands Resource Conservation District on 18 September 2001.

Several Land Retirement Team members attended a one-day workshop on restoration

techniques on 13 August 2001. That workshop was sponsored by the United States

Bureau of Land Management, was presented by Craig Dremann of The Reveg Edge, and

was held at the Kern National Wildlife Refuge in Tulare County, CA. A number of Land

Retirement Team staff also attended the national conference of The Wildlife Society held

in Reno, NV. in September 2001. The Point Reyes Bird Observatory Landbird

Monitoring Training Workshop held 4-8 June 2001 and the Central Valley Birding

Symposium held 15-8 November 2001 were also attended by an LRT staff member.
Land Retirement Demonstration Program: Year 3

133

VI. REFERENCES

Balistrieri, L.S., and T.T. Chao. 1987. Selenium adsorption by Goethite. Soil Science Society

of America. 51:1145-51.

Beard, S., R Fujii., and G. Shanks. 1994. Water quality, lithologic, and water-level Data for

wells in Tulare Basin, Kings, Kern, and Tulare counties, California, August 1990 to

February 1993: U.S. Geological Survey Open File Report 94-334, U.S. Geological Survey,

Sacramento, California, 29p.

Beason, R.C. 1995. Horned Lark (Eremophila alpestris). In The birds of North America. No.

195 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and the

American Ornithologists' Union, Washington D.C., 24pp.

Belitz, K., and F.J. Heimes. 1990. Character and evolution of the ground-water flow system in

the central part of the western San Joaquin Valley, California, U.S. Geological Survey,

Denver, CO, U.S. Geological Survey Water-Supply Paper 2348:1-28.

Bonham, C. 1989. Measurements for terrestrial vegetation. John Wiley & Sons, New York,

New York, 338pp.

Bull, W.B. 1964a. Geomorphology of segmented alluvial fans in western Fresno County,

California. U.S. Geological Survey, Denver, CO, U.S. Geological Survey Professional

Paper 352-E:89-129.

Bull, W.B., 1964b. Alluvial fans and near-surface subsidence in western Fresno County,

California. U.S. Geological Survey, Denver, CO, U.S. Geological Survey Professional

Paper 437-A:1-71.

California Department of Food and Agriculture. 2001. Pest ratings of noxious weed species and

noxious weed seed. URL: http://pi.cdfa.ca.gov/weedinfo/. Accessed 19 February 2002.

California Department of Water Resources. 2000. CIMIS weather station information,

Explanation of ETo. URL: http://wwwdpla.water.ca.gov/cimis/cimis/hq/etoexpl.txt.

Accessed 17 September 2002.

California Exotic Pest Plant Council. 1999. Pest plants of greatest ecological concern, (Online).

URL: http://www.caleppc.org/info/pestplants99.pdf. Accessed 2 February 2002.

CH2M Hill. 1999. Quality assurance project plan, Land Retirement Demonstration Project—

soil, groundwater, and surface water monitoring, under contract to the U.S. Bureau of

Reclamation, South Central California Area Office, Fresno, California. 41 pp.

Churchfield, S. 1990. The natural history of shrews. Cornell University Press, Ithaca, NY, 178

pp.
Land Retirement Demonstration Program: Year 3

134

Clark, J. and G. Rollings. 1996. Farming for Wildlife. Voluntary practices for attracting

wildlife to your farm. 40pp.

Davis, G.H. 1961. Geologic control of mineral composition of stream waters of the eastern

slope of the southern Coast Ranges, California: Geochemistry of Water. U.S. Geological

Survey, Denver, CO, U.S. Geological Survey Water-Supply Paper 1535-B:B1-B30.

Deverel, S.J., and R. Fujii. 1988. Processes affecting the distribution of selenium in shallow

groundwater of agricultural areas, western San Joaquin Valley, California. Water Resources

Research 24(4):516-524.

Deverel, S.J., and S.P. Millard. 1988. Distribution and mobility of selenium and other trace

elements in shallow groundwater of the western San Joaquin Valley, California.

Environmental Science and Technology 22(6): 697-702.

Deverel, S.J., and S.K. Gallanthine. 1989. Relation of salinity and selenium in shallow

groundwater to hydrologic and geochemical processes, western San Joaquin Valley,

California. Journal of Hydrology 109:25-49.

Dubrovsky, N.M., S.J. Deverel, and R.J. Gilliom. 1993. Multiscale approach to ground-waterquality assessment: selenium in the San Joaquin Valley, California. Pp. 537-560 in

Regional groundwater quality (W.M Alley, ed.). Van Nostrand Reinhold, NY, 560 pp.

Dunk, J.R. 1995. White-tailed Kite (Elanus leucurus). In The Birds of North America, No. 178

(A. Poole and F. Gill, eds.) The Academy of Natural Sciences, Philadelphia, and The

American Ornithologists' Union, Washington D.C. 16pp.

Elrashadi, A.M., D.C. Adriano, S.M. Workman, and W.L. Lindsay. 1987. Chemical equilibria

of selenium in soils: a theoretical development. Soil Science 144(2):141-52.

Frost, R.R, and R.A. Griffin. 1977. Effect of pH on adsorption of arsenic and selenium from

landfill leachate by clay minerals. Soil Science Society of America Journal, 41:53-57.

Fujii, R., and W.C. Swain. 1995. Area distribution of selected trace elements, salinity, and

major ions in shallow groundwater, Tulare Basin, southern San Joaquin Valley, California.

U.S. Geological Survey Water Resources Investigation Report 95-4048, 65 pp.

Gat, J.R., and R. Gonfiantini (eds.), 1981. Stable isotope hydrology—deuterium and oxygen-18

in the water cycle. Technical Report Series of the International Atomic Energy Agency, 210

pp.

Gill, F. B. 1995. Ornithology, 2nd edition. W.H. Freeman, NY, 720 pp.

Goldberg, S., and R.A. Glanbig. 1988. Anion sorption on a calcareous Montmorillonitic soil—

selenium. Soil Science Society of America Journal, 52: 954-958.
Land Retirement Demonstration Program: Year 3

135

Gul, B., and D.J. Weber. 1997. Alleviation of seed dormancy in Allenrolfea occidentalis.

Abstract: Botanical Society of America annual meeting at Montreal, Quebec, Canada,

August 3-9.

Heady, H.F. 1997. Valley grassland. Pp. 491-514, In Terrestrial vegetation of California (M.

Barbour and J. Major, eds.). John Wiley & Sons, NY, 1030 pp.

Hill, M.O., and H.G. Gauch, Jr. 1980. Detrended correspondence analysis: an improved

ordination technique. Vegetation 47:47-58.

Holland, R. F. 1986. Preliminary descriptions of the terrestrial natural communities of

California. State of California Department of Fish and Game, Sacramento, 156 pp.

Hingston, F.J., A.M. Posner, and J.P. Quirk. 1974. Anion adsorption by goethite and gibbsite.

Soil Science 25:16-26.

Holling, C.S., ed. 1978. Adaptive environmental assessment and management. Wiley, NY, 377

pp.

Holstein, G. 2001. Pre-agricultural grassland in central California. Madroño 48:253-264.

Ingles, L.G. 1947. Mammals of the Pacific States. Stanford University Press, Stanford

University, Calif. 506pp.

Kaufman, K. 1996. Lives of North American Birds. Houghton Mifflin Company, New York,

NY. 675pp.

Kent, M., and P. Coker. 1992. Vegetation description and analysis: a practical approach.

Belhaven Press, London, 363pp.

Keren, R., and F.T. Bingham. 1985. Boron in water, soils and plants. Pp. 229-276, in

Advances in soil science (B.A. Stewart, ed.). Springer-Verlag, NY, 1:1-276.

Khan, M.A., B. Gul, and D.J. Weber. 2002. Improving seed germination of Salicornia rubra

(Chenopodiaceae) under saline conditions using germination-regulating chemicals. Western

North American Naturalist 62:101-105.

Lawrence Berkeley Laboratory. 1987. Hydrological, geochemical, and ecological

characterization of Kesterson Reservoir. Annual Report, October 1986 - September,

University of California, Earth Sciences Division, Lawrence Berkely Laboratory.

Leckie, J.O., M.M. Benjamin, K. Hayes, G. Kanjman, and S. Altman. 1980. Co-precipitation of

trace elements from water with iron oxyhydroxide. Electric Power Research Institute Report

CS-1513:4.4-4.18, Palo Alto, California.

McCune, B., and M. J. Mefford. 1997. PC-ORD for Windows. Multivariate Analysis of

Ecological Data. Version 3.06. MjM Software, Gleneden Beach, OR.
Land Retirement Demonstration Program: Year 3

136

Miller, R.E., J.H. Green, and G.H. Davis. 1971. Geology of the compacting deposits in the Los

Banos-Kettleman City subsidence area, California. U.S. Geological Survey, Denver, CO,

U.S. Geological Survey Professional Paper 497-E:1-46.

Neal, R.H., G. Sposito, K.M. Holtzclaw, and S.J. Traina. 1987. Selenite adsorption on alluvial

soils I: soil composition and pH effect. Soil Science Society of America Journal, 51:1161-

1165.

Page, R.W. 1986. Geology of the fresh ground-water basin of the Central Valley, California,

with texture maps and sections: U.S. Geological Survey Professional Paper 1401-C, 54 p.

Perry, D.M., I.S. Suffet, M. Wilhelm, J.A. Noblet, and A. Maliglig, 1994. Boron Environmental

Chemistry, Distribution, Bioaccumulation, and Toxicity in Aquatic Ecosystems and

Recommendations for Establishment of a Boron Water Quality Criterion for Natural Waters

in the San Joaquin Valley, California. Final Report for Contract No. 1-192-150-0, submitted

to the California Regional Water Quality Control Board, Central Valley Region and the

California Environmental Protection Agency, 270pp.

Presser, T.S., and I. Barnes. 1984. Selenium concentrations in waters tributary to and in the

vicinity of Kesterson National Wildlife Refuge, Fresno and Merced counties, California.

U.S. Geological Survey Water-Resources Investigations Report 84-4122:1-26. Menlo Park,

California.

Presser, T.S., W.C Swain, R.R. Tidball, and R.C. Severson. 1990. Geologic sources,

mobilization, and transport of selenium from the California Coast Range to the western San

Joaquin Valley: a reconnaissance study. U.S. Geological Survey Water-Resources

Investigations Report 90-4070:1-66. Menlo Park, California.

Prokopovich, N.P. 1987. Textural composition of near-surface alluvium in west- San Joaquin

Valley, California. . Bulletin Association Engineering Geologists 24:59-81.

Pruitt, W. O. and J. Doorenbos. 1977. Proceedings of the International Round Table Conference

on Evapotranspiration, Budapest, Hungary.

Rosenfeld, I. and O.A. Beath. 1964. Selenium: geobotany, biochemistry, toxicity, and nutrition.

Academic Press, NY. 411 pp.

Selmon, M., P. Kelly, and C. Uptain. 1999. Resource monitoring plan for the Land Retirement

Demonstration Project in Western Fresno County. California State University, Stanislaus,

Foundation, Fresno, California. 36 pp.

Selmon, M., P. Kelly, C. Uptain, and S. Lee. 2000. Land Retirement Demonstration Project

1999 annual report. Unpubl. report prepared for the Interagency Land Retirement Team,

Fresno, California, 84 pp.

Smith, R.B. 2001. Evaluation of irrigation system alternatives—Atwell Island Irrigation District

area, U.S. Bureau of Reclamation, Fresno, California. pp. 1-27.
Land Retirement Demonstration Program: Year 3

137

StatSoft, Inc. 1999. STATISTICA for Windows. Version 5.5a. StatSoft, Inc., Tulsa, OK.

Stickel, L.F. 1968. Home range and travels. Pp. 373-411, in Biology of Peromyscus (Rodentia)

(J.A. King, ed.). American Society of Mammalogists, Special Publication 2: 593 pp.

St. John, T. 1995. Specially-modified land imprinter inoculates soil with mycorrhizal fungi.

Restoration Management Notes. 14:84-85.

Swain, W.C., and L. Duell. 1993. Water quality data for shallow wells in the western and

southern Tulare Basin, San Joaquin Valley, California, May to August 1989. U.S.

Geological Survey Open File Report 92-655:1-30p, Sacramento, California.

U.S. Bureau of Land Management. 2001. Atwell Island, ditch maintenance EA. Administrative

Document on file at USBLM, Bakersfield Field Office. 12 pp.

U.S. Bureau of Reclamation. 1982. Irrigation suitability land classification report, Atwell Island

Water District, Fresno, California, pp. 1-60.

U.S. Department of Agriculture. 1992. Unpubl. soil sample data for western Fresno County,

Tranquillity area, California. Natural Resources Conservation Service, Fresno, California.

U.S. Department of Agriculture. 1996. Unpubl. soil survey data for western Fresno County,

California. Natural Resources Conservation Service, Fresno, California, 294 pp.

U.S. Department of Interior. 1998. Guidelines for interpretation of the biological effects of

selected constituents in biota, water, and sediment. National irrigation water quality

program information report No. 3. 198 pp+.

U.S. Environmental Protection Agency, 1986. Quality criteria for water: U.S. EPA 440/5-86-

001, May 1986, 453 pp.

U.S. Environmental Protection Agency, 1988. Water quality criteria documents: Federal

Register, v.53, no. 2, pp.177-179.

U.S. Department of Interior. 1997. Central Valley Project Improvement Act Section 3408(h):

Land Retirement Program guidelines. Unpubl. report by the Interagency Land Retirement

Team, Fresno, California. 19 pp.

U.S. Department of Interior. 1999. Final Environmental Assessment: Central Valley Project

Improvement Act Land Retirement Program Demonstration Project. Unpubl. report by the

Interagency Land Retirement Team, Fresno, California, 127 pp.

U.S. Fish and Wildlife Service. 1998. Recovery Plan for Upland Species of the San Joaquin

Valley, California. Region 1, Portland, OR, 319 pp.

Uptain, C., T. Sandoval, G. Moise, and P. Kelly. 1998. Preliminary biological survey for the

Nickell property, Kings Co., California. Unpublished report to the United States Bureau of

Reclamation, Fresno, California, 21 pp.
Land Retirement Demonstration Program: Year 3

138

Uptain, C., K. Dulik, P. Brandy, M. Selmon, P. Kelly, D. Williams, S. Lee, and J. Brummer.

2001. Land Retirement Demonstration Project 2000 Annual Report to the Interagency Land

Retirement Team, Fresno, California, 113 pp.

Vickery, P.D., P.L. Tubaro, J.M. Cardoso Da Silva, B.G. Peterjohn, J.R. Herkert, and R.B.

Cavalcanti. 1999. Conservation of grassland birds in the Western Hemisphere. Studies in

Avian Biology 19:2-26.

Walters, C.J., and C.S. Holling. 1990. Large scale management experiments and learning by

doing. Ecology 71:2060-2068.

Weres, O., A. R. Jaoni, and L. Tsao. 1989. The distribution, speciation, and geochemical

cycling of selenium in a sedimentary environment, Kesterson Reservoir, California, U.S.A.

Applied Geochemistry 4:543-63.

White, A.F., S.M. Benson, A.W. Yee, H.A. Wollenberg, Jr., and S. Flexser. 1988. Groundwater

contamination at the Kesterson Reservoir, California: geochemical parameters influencing

selenium mobility. Water Resources Research, 27:1085-1098.

Zeiner, D.C., W.F. Laudenslayer, Jr., K.E. Mayer, and M. White (eds.). 1990. California's

Wildlife, Volume III. Mammals. California Statewide Wildlife Habitat Relationships

System, California Department of Fish and Game, Sacramento, California, 407 pp.
Land Retirement Demonstration Program: Year 3

139

VII. APPENDICES

A. Additional Vegetation Tables

Table A1. Overview of species encountered during all vegetation sampling at the Tranquillity

HRS site.

Pre-project inventory4 HRS sampling6

Family Binomial1

Life

history2 Origin3

Sec.

10

Sec.

15

Sec.

16

Apnd

E5 1999 2000 2001

Amaranthaceae Amaranthus sp. AH N.A. - - + + - - -

Asclepiadaceae Asclepias fascicularis PH N - - - - - +7 -

Carthamus tinctorius AH I + - - + - - -

Centaurea solstitialis AH I + - + + - - -

Conyza canadensis AH N + + - + - - -

Helianthus annuus AH N + + - + - - -

Hemizonia pungens* AH N - - - - - - +

Isocoma acradenia* S N - - - - -+-

Lactuca serriola AH I + + - + + + +

Lasthenia californica* AH N - - - - - + +

Microseris sp. AH (?) N - - + - - - -

Picris echioides A/PH I - - - - - - -

Senecio vulgaris AH I - - + + + + -

Sonchus asper AH I + - - + + - -

Sonchus oleraceus AH I + + + + + + +

Asteraceae

Xanthium strumarium AH N - - + + - - -

Amsinckia menziesii AH N - - - - - - +

Boraginaceae Heliotropium

curassavicum* PH N - - - + - - -

Brassica nigra AH I - - - + + + +

Capsella bursa-pastoris AH I - + - + + + +

Hirschfeldia incana PH I + - + + - - -

Raphanus sativus A/BH I + - - + - - -

Brassicaceae

Sisymbrium irio AH I - - - + + + +

Atriplex argentea AH N + + - - + + +

Atriplex patula AH N - - - - - - -

Atriplex polycarpa* S N - - - - ---

Beta vulgaris PH I - - - + + + +

Chenopodium album AH I - - + + + + -

Chenopodiaceae

Monolepis nuttalliana AH N - - - - - + -
Land Retirement Demonstration Program: Year 3

140

Pre-project inventory4 HRS sampling6

Family Binomial1

Life

history2 Origin3

Sec.

10

Sec.

15

Sec.

16

Apnd

E5 1999 2000 2001

Salsola tragus AH I + - - + - - +

Chenopodiaceae Suaeda moquinii* PH N - - - - - + +

Calystegia sp. V (?) N - - + - - - - Convolvulaceae

Convolvulus arvensis PH/V I - - - + + + -

Medicago sativa PH I - - - - - - +

Fabaceae

Melilotus indica AH I + + + + + + +

Frankeniaceae Frankenia salina* PH N - - - - - + -

Geraniaceae Erodium cicutarium AH I - - - + + + +

Hydrophyllaceae Phacelia distans AH N - - - + + + +

Juncaceae Juncus sp. N.A. N.A. - - - + - - -

Eremalche parryi AH N - - - + + +7 -

Malvaceae Malva parviflora AH I - - - - + + -

Malvella leprosa PH N - - + + - + -

Onagraceae Epilobium brachycarpum AH N + - - + - - -

Avena fatua AH I + - + + + + +

Bromus carinatus* AH N - - - - - + +

Bromus diandrus AH I - - - - - - +

Bromus hordeaceus AH I + - - + - - -

Bromus madritensis AH I + - + + + + +

Crypsis schoenoides AH I - - + + - - -

Cynodon dactylon PH I - - - - - - -

Distichlis spicata PH N + - - + - - -

Hordeum depressum AH N - - - + + + -

Hordeum marinum AH I + - + + - - -

Hordeum murinum AH I + - - + + + +

Hordeum vulgare AH C - - - + + + +

Leptochloa uninervia AH N - - + + - - -

Leymus triticoides* PH N - - - - - - +

Phalaris minor AH I + + + + - + +8

Polypogon monspeliensis AH I - + - + - - -

Poaceae

Vulpia microstachys* AH N - - - - - + +

Polemoniaceae Gilia tricolor AH N - - - - - - -

Polygonum sp. N.A. N.A. - - - - - - - Polygonaceae Rumex crispus PH I + - + + - - -

Sapotaceae Bassia hyssopifolia AH I - - - - - - +

Physalis lanceifolia AH I + - + + - - -

Solanaceae

Solanum americanum A/PH N - - - - - + -

Tamaricaceae Tamarix ramosissima T or S I - - - + - - -
Land Retirement Demonstration Program: Year 3

141

Table A2. Overview of species encountered in Tranquillity HRS vegetation sampling, 2001.

Species marked with an asterisk are imprinted species. Roman numerals indicate study Block.

Numerical values in cells indicate mean percent cover for that particular species in that plot.

Contoured/imprinted Not contoured/ imprinted Contoured/not imprinted

Not contoured/not

Imprinted Taxon

code O2

I II III IV V I II III IV V I II III IV V I II III IV V

AMME N - - - - - - - - - - - - - - - 0.13 - - - -

ATAR N 0.19 - 18.90 0.15 0.02 1.54 - 3.23 6.29 - 0.13 - 0.25 0.63 - - 0.02 3.56 4.29 0.02

AVFA I 0.13 2.00 - - - - 1.69 4.46 - 0.13 0.19 3.19 6.19 - 1.25 - 14.10 21.04 - -

BAHY I - - - - - - - - - - - - - 0.02 - - - - - -

BEVU I 7.15 - - - 0.13 - - - - - 0.02 - - - - - - - - -

BRCA* N - - 0.02 - - - - - 0.13 - - - - - - - - - - -

BRDI I 0.02 - - - - - - 0.13 - - - - - - - - - - - -

BRMA I 11.65 - - - - 25.31 0.02 0.02 - - 18.46 - - 3.23 - 66.67 - - - 0.25

BRNI I 0.90 - - - 16.19 0.79 - 0.02 3.54 4.94 0.02 - - - 38.23 0.58 0.71 - 0.13 -

CABU I - 2.63 - 0.13 0.21 - 8.19 0.50 - 0.13 - 1.35 - - 0.25 - 1.15 4.31 - 0.04

ERCI I 1.19 - - - - 0.33 - - - - 0.52 - - - - 1.00 - - - -

HEPU* N - - - - - - - 0.02 - - - - - - - - - - - -

HOMU I 5.13 - - - 0.13 21.73 - 0.02 - 0.75 33.75 - - 2.56 3.54 1.04 - - - 0.63

HOVU C 0.56 16.31 1.94 0.02 0.15 0.19 13.58 4.48 0.81 - 0.19 6.46 6.19 0.15 - 0.56 17.60 1.31 0.15 -

LACA* N - 0.15 0.02 - - 0.06 0.21 0.04 0.04 - - - - - - - - - - -

LASE I 0.04 0.56 1.46 1.02 - 0.04 0.17 0.90 0.21 - 0.06 0.27 1.40 - - - 1.83 2.19 4.63 -

LETR N 0.02 0.02 - - - - 0.06 0.15 - - - - - - - - - - - -

MEIN I 3.94 0.15 0.69 - - 5.88 0.02 2.98 - - 7.17 0.02 6.44 - - 9.13 1.52 2.77 - -

MESA I - - - - - - - - - - - - - - - - - - 0.02 -

PHSP NA 0.08 - - - - 0.02 - - - - 0.13 - - - - - 0.02 - - 0.13

PHDI N 1.52 - - - - - - - - - - - - - - - - - - -

SATR I - - 4.33 0.65 - - - - - - - - 0.75 - - 0.13 - 1.71 - -

SIIR I - 9.04 7.50 1.44 19.42 - 11.92 6.35 13.96 19.06 - 15.77 0.88 16.54 27.69 - 4.94 5.85 9.08 53.33

SOOL I 0.10 0.63 1.92 0.13 - 0.02 0.23 1.65 - - 0.02 0.02 0.13 - - 0.02 0.15 1.00 1.31 -

SUMO* N - 0.63 0.02 - - - - - - - - - - - - - - - - -

VUMI* N - 0.94 - - - 0.02 0.71 0.13 - - - - - - - - - - - -

Spp. Rich.3: 15 11 10 7 7 12 11 16 7 5 12 7 8 6 5 9 10 9 7 6

1. Taxon Code: AMME, Amsinckia menziesii; ATAR, Atriplex argentea; AVFA, Avena fatua; BAHY, Bassia

hyssopifolia; BEVU, Beta vulgaris; BRCA, Bromus carinatus; BRDI, Bromus diandrus; BRMA, Bromus

madritensis subsp. rubens; BRNI, Brassica nigra; CABU, Capsella bursa-pastoris; ERCI, Erodium cicutarium;

HEPU, Hemizonia pungens; HOMU, Hordeum murinum; HOVU, Hordeum vulgaris (Barley); LACA, Lasthenia

californica; LASE, Lactuca serriola; LETR, Leymus triticoides; MEIN, Melilotus indica; MESA, Medicago sativa ;

PHSP, Phalaris sp.; PHDI, Phacelia distans; SATR, Salsola tragus; SIIR, Sisymbrium irio; SOOL, Sonchus

oleraceus; SUMO, Suaeda moquinii; VUMI, Vulpia microstachys.

2. Origin: N, Native; I, Introduced; C, Cultivar (Barley); NA, not known.

3. Species Richness: number of species observed in a particular plot.
Land Retirement Demonstration Program: Year 3

142

Table A3. Frequency of species noted during vegetation sampling, 2001. Species marked with

an asterisk are those included in the seed mix.

Species Origin Plot1 Quadrat2

Amsinckia menziesii Native 1 1

Atriplex argentea Native 14 50

Avena fatua Introduced 11 82

Bassia hyssopifolia Introduced 1 1

Beta vulgaris Introduced 3 13

Bromus carinatus* Native 2 2

Bromus diandrus Introduced 2 2

Bromus madritensis subsp. rubens Introduced 8 94

Brassica nigra Introduced 11 72

Capsella bursa-pastoris Introduced 11 70

Erodium cicutarium Introduced 4 28

Hemizonia pungens* Native 1 1

Hordeum murinum Introduced 10 82

Hordeum vulgare (Barley) Introduced 17 159

Lasthenia californica* Native 6 15

Lactuca serriola Introduced 14 76

Leymus triticoides* Native 4 7

Melilotus indica Introduced 12 98

Medicago sativa Introduced 1 1

Phalaris sp. Introduced 5 13

Phacelia distans Native 1 5

Salsola tragus Introduced 5 13

Sisymbrium irio Introduced 16 264

Sonchus oleraceus Introduced 14 40

Suaeda moquinii Native 2 2

Vulpia microstachys Native 4 18

Summed Frequency of Introduced Species: 1,108

Summed Frequency of Native Species: 101

1. Frequency of plots in which a particular species was noted.

2. Frequency of quadrats in which a particular species was noted.
Land Retirement Demonstration Program: Year 3

143

Table A4. Overview of species encountered during the pre-project inventory of the Atwell

Island site and baseline vegetation sampling of the Atwell Island HRS plots.

Freq.1 Cover2 Site cover3 Species/morpho-species Family Origin4 Life history5 A6 B7 C8

381 30.96 31.120 Hordeum vulgare {Barley} Poaceae B AH - - -

208 4.52 2.497 Hordeum murinum Poaceae I AH + + +

168 5.20 2.289 Melilotus indica Fabaceae I AH + + +

124 1.75 0.565 Amsinckia menziesii Boraginaceae N AH + + +

124 6.42 2.107 Phalaris minor Poaceae I AH - + +

114 10.14 3.089 Avena sativa Poaceae I A/P - - -

111 3.63 1.059 Erodium cicutarium Geraniaceae I AH + + +

77 5.31 1.065 Medicago polymorpha Fabaceae I AH - - -

52 1.21 0.164 Chenopodium sp. Chenopodiaceae N.A. H - - -

51 1.65 0.219 Sisymbrium irio Brassicaceae I AH + + +

50 0.80 0.104 Bromus m. subsp. rubens Poaceae I AH + + +

49 0.86 0.109 Capsella bursa-pastoris Brassicaceae I AH - - -

38 0.62 0.061 Unknown Cordate Leaved N.A. N.A. N.A. - - -

36 1.88 0.176 Atriplex argentea Chenopodiaceae N AH + + +

36 0.71 0.066 Vulpia myuros Poaceae I AH - - -

24 0.92 0.057 Narrow Leaf Grass Poaceae N.A. H - - -

24 0.71 0.044 Sonchus oleraceus Asteraceae I AH - + -

24 4.29 0.268 Spergularia sp. Caryophyllaceae N.A. H - - -

22 1.07 0.061 Poa annua Poaceae I AH - - -

21 7.50 0.410 Polygonum sp. Polygonaceae N.A. H - - -

18 3.61 0.169 Polypogon monspeliensis Poaceae I AH - + -

14 1.21 0.044 Lactuca serriola Asteraceae I AH + + -

12 26.88 0.840 Bassia hyssopifolia Chenopodiaceae I AH + + +

11 2.09 0.060 Bromus diandrus Poaceae I AH - + +

11 0.73 0.021 Lolium sp. Poaceae I H - - -

10 0.75 0.020 Shiny Grass Poaceae N.A. H - - -

10 0.50 0.013 Sonchus sp. Asteraceae I H - - -

8 4.19 0.087 Brassica nigra Brassicaceae I AH - + -

7 2.57 0.047 Atriplex sp. Chenopodiaceae N.A. S (?) - - -

6 0.50 0.008 Cressa truxillensis Convolvulaceae N PH + + +

5 0.50 0.007 Malva parviflora Malvaceae I AH - + +

4 4.75 0.050 Carthamus tinctorius Asteraceae I AH - - -

4 1.13 0.012 Unknown Narrow Leaved N.A. N.A. N.A. - - -

4 2.38 0.025 Unknown Shiny Leaf N.A. N.A. N.A. - - -

2 1.75 0.009 Annual Atriplex Chenopodiaceae N.A. S (?) - - -

2 1.75 0.009 Unknown toothed leaf. N.A. N.A. N.A. - - -

2 0.50 0.003 Unknown w/ red cotyledons N.A. N.A. N.A. - - -

2 0.50 0.003 Unknown with Fleshy Leaf N.A. N.A. N.A. - - -

1 3.00 0.008 Digitaria sp. Poaceae I H - - -

1 0.50 0.001 Hemizonia pungens Asteraceae N AH + + +

1 15.00 0.039 Hordeum sp. Poaceae N.A. H - - -

1 0.50 0.001 Monolepis nuttalliana Chenopodiaceae N AH - + -

1 0.50 0.001 Senecio vulgaris Asteraceae N.A. AH - - -

1 0.50 0.001 Unknown Grass Poaceae N.A. H - - -

1 0.50 0.001 Unknown Hairy Leaved N.A. N.A. N.A. - - -

1 0.50 0.001 Unknown Hairy Ovate

Leaved N.A. N.A. N.A. - - -

1 0.50 0.001 Unknown Lanceolate N.A. N.A. N.A. - - -
Land Retirement Demonstration Program: Year 3

144

Freq.1 Cover2 Site cover3 Species/morpho-species Family Origin4 Life history5 A6 B7 C8

Leaved

1 0.50 0.001 Unknown Mustard Brassicaceae N.A. H - - -

1 0.50 0.001 Unknown species N.A. N.A. N.A. - - -

-- - Acroptilon repens Asteraceae I PH - + -

-- - Allenrolfea occidentalis Chenopodiaceae N S + - -

-- - Distichlis spicata Poaceae N PH + + +

-- - Helianthus annuus Asteraceae N AH + + -

-- - Heliotropium curassavicum Boraginaceae N PH + + -

-- - Isocoma acradenia Asteraceae N S + + -

-- - Malvella leprosa Malvaceae N PH - + -

-- - Medicago sativa Fabaceae I PH - + -

-- - Rumex crispus Polygonaceae I PH - + +

-- - Salsola tragus Chenopodiaceae I AH + + -

-- - Scirpus acutus Cyperaceae N PH - - +

-- - Sesuvium verrucosum Aizoaceae N PH + + +

-- - Tamarix parviflora Tamaricaceae I T or S + - -

1. Frequency: the number of quadrats in which the taxon was noted. Species with no values listed were those

encountered during the pre-project Inventory (2000) that were not observed in sampling quadrats during the

baseline survey (2001).

2. Estimated mean percent cover of the taxon calculated from only those quadrats in which the species was noted.

Percent cover values were estimated from midpoints of the cover class (e.g., a species with an estimated cover

of 5-25% was evaluated as having a cover of 15%).

3. Estimated site-wide mean percent cover calculated from the summed cover data divided by the total number

(384) of quadrats.

4. Key to Origins: B, Barley; I, Introduced; N, Native; N.A., Not Known.

5. Key to Life History: ,H, Herb; AH, Annual Herb; PH, Perennial Herb; APH, Annual or Perennial Herb; S, Shrub;

T, Tree; N.A., Not Known.

6. Species encountered in Area A during the pre-project Inventory (see Figure 19).

7. Species encountered in Area B during the pre-project Inventory (see Figure 19).

8. Species encountered in Area C during the pre-project Inventory (see Figure 19).
Land Retirement Demonstration Program: Year 3

145

B. Rank-abundance Graphs Generated from Vegetation Sampling on theTranquillity Habitat Restoration Study Plots, 1999-2001Figure B1. Rank-abundance curves for the Block 1 study plots, Tranquillity HRS.
Land Retirement Demonstration Program: Year 3

146

Figure B2. Rank-abundance curves for the Block 2 study plots, Tranquillity HRS.
Land Retirement Demonstration Program: Year 3

147

Figure B3. Rank-abundance curves for the Block 3 study plots, Tranquillity HRS.
Land Retirement Demonstration Program: Year 3

148

Figure B4. Rank-abundance curves for the Block 4 study plots, Tranquillity HRS.
Land Retirement Demonstration Program: Year 3

149

Figure B5. Rank-abundance curves for the Block 5 study plots, Tranquillity HRS.
Land Retirement Demonstration Program: Year 3

150

C. Avian Species Observed on the Tranquillity Habitat

Restoration Study Plots, 1999-2001

Table C1. Avian species observed on the Tranquillity HRS plots, 1999-2001.

Avian code Common name1 Scientific name Status2 1999 2000 2001

AMCR American Crow Corvus brachyrhynchos +++

AMKE American Kestrel* Falco sparverius +++

AMPI American Pipit** Anthus rubescens +-+

BAOW Barn Owl* Tyto alba - ++

BARS Barn Swallow Hirundo rustica +++

BHCO Brown-headed Cowbird* Molothrus ater - -+

BNST Black-necked Stilt Himantopus mexicanus +--

BRBL Brewer's Blackbird* Euphagus cyanocephalus +++

BUOW Burrowing Owl** Athene cunicularia FSC/CSC - - +

CLSW Cliff Swallow Petrochelidon pyrrhonota +++

CORA Common Raven Corvus corax ++-

HOFI House Finch Carpodacus mexicanus +++

HOLA Horned Lark** Eremophila alpestris CSC + + +

KILL Killdeer* Charadrius vociferus +++

LASP Lark Sparrow* Chondestes grammacus +--

LBCU Long-billed Curlew** Numenius americanus CSC + + +

LOSH Loggerhead Shrike* Lanius ludovicianus FSC/CSC + + +

MALL Mallard* Anas platyrhynchos +++

MOPL Mountain Plover** Charadrius montanus FPT/CSC - + -

NOHA Northern Harrier** Circus cyaneus CSC + + +

NOMO Northern Mockingbird Mimus polyglottos +-+

PRFA Prairie Falcon* Falco mexicanus CSC - + -

RNPH Ring-necked Pheasant* Phasianus colchicus - ++

RTHA Red-tailed Hawk Buteo jamaicensis -+-

RWBL Red-winged Blackbird* Agelaius phoeniceus +++

SAPH Say's Phoebe* Sayornis saya - -+

SAVS Savannah Sparrow** Passerculus sandwichensis +++
Land Retirement Demonstration Program: Year 3

151

Avian code Common name1 Scientific name Status2 1999 2000 2001

SEOW Short-eared Owl** Asio flammeus CSC - + +

SOSP Song Sparrow Melospiza melodia - ++

WCSP White-crowned Sparrow Zonotrichia leucophrys +++

WEKI Western Kingbird* Tyrannus verticalis +++

WEME Western Meadowlark** Sturnella neglecta +++

WESA Western Sandpiper Calidris mauri +--

WHIM Whimbrel Numenius phaeopus +--

WTKI White-tailed Kite Elanus leucurus +++

YHBL Yellow-headed Blackbird Xanthocephalus

xanthocephalus +--

YRWA Yellow-rumped Warbler Dendroica coronata - -+

1 * = Facultative grassland specialist; **, Obligate grassland specialist as in Vickery et al. 1999.

3 Key to status: FSC, Federal Special Concern species; CSC, CA Special Concern Species; FPT, Federally

proposed for listing as Threatened.