Progress 03/27/09 to 06/02/13
Outputs
Progress Report Objectives (from AD-416): The Integrated Invasive Species Control, Revegetation, and Assessment of Great Basin Rangelands project has two objectives: 1) Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices and 2) Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Approach (from AD-416): The research project is organized into four complementary components: (1) ecology and control of invasive plants, (2) revegetation of degraded rangelands, (3) maintaining and/or enhancing healthy rangelands, and (4) quantifying economic and environmental impacts of management practices at the landscape scale. Experiments will be conducted to understand the seed and seedbed ecology of several native and non-native grasses and shrubs. Herbicides and tillage will be used to vary content of competing vegetation as it affects shrub establishment. Research will be conducted to document ecological processes which control expansion of Western Juniper. Levels of genetic variation of selected plants will be compared between high and low quality ecological conditions sites to determine effects of disturbance on genetic diversity. Rainfall simulators will be used to characterize runoff and soil erosion processes at the scale of a plant community under different manipulative treatments (altered grazing practices, burning, and brush removal) to quantify the hydrologic impact of the conservation practices. The SWAT model will be utilize to evaluate which alternative management scenarios (i.e., a change in vegetation state as represented by changes in canopy and ground cover or vegetation composition by life form) are the most cost effective in achieving the desired environmental benefit. Formerly 5325-11220-006-00D (June, 2011). This is the final report for this project which has been replaced by new project 5370-13610-001-00D, "Invasive Species Assessment and Control to Enhance Sustainability of Great Basin Rangelands". The Great Basin Rangelands Research Unit (GBRRU) in Reno, Nevada, has developed new herbicidal techniques and seed mixtures to increase the variety and density of desirable native and introduced species to rehabilitate degraded Great Basin rangelands. In one study, ARS researchers were able to establish 3.9 perennial grasses ft-� in areas where cheatgrass had died-off from natural causes compared to 0.6 ft-� outside of the die-off zone. We found that by disking sites that were still dominated by cheatgrass prior to seeding, the resulting action buried the majority of cheatgrass seeds and prevented the cheatgrass seeds from germinating. This resulted in an 83% decrease in cheatgrass densities and a corresponding increase of 244% establishment of desirable seeded species. The combination of these results was sufficient to decrease fuel loads and significantly reduced the risk of wildfire and provides a variety of treatments for reducing the impact of cheatgrass. GBRRU has investigated passive approaches to rangeland restoration. Results of a successful field experiment using �diversionary seeds� to enhance seedling recruitment of Indian ricegrass from seeds cached by small mammals were published. Research on animal seed-dispersal vectors of expanding populations of western juniper was conducted comparing germination rates of seeds dispersed by birds, by small mammals, and by neither of these seed dispersers. Cumulative results clearly indicated that a two-phase dispersal system yields the best seedling recruitment in which birds consume fruits, defecate the seeds, and small mammals then harvest and cache the seeds from the bird droppings. GBRRU has completed studies to document how the exotic annual grass, cheatgrass, alters biogeochemical cycling and nutrient availability and basic understanding of the competitive nature of the plant. Currently, physical-based overland flow erosion models for rangeland applications do not separate disturbed and undisturbed conditions in modeling concentrated flow and total sediment yield. Therefore, it is difficult to estimate benefits of conservation practices. GBRRU found that burning increases erosion by amplifying the power of overland flow because wildfire removes obstacles and changes soil properties affecting erodibility itself. GBRRU observed concentrated flow erodibility had a high value at overland flow initiation and then started to decline with time due to reduction of sediment availability from the scoured soil surface. We developed new empirical functions to predict erodibility variation within a runoff event as a function of cumulative unit discharge. Empirical equations were also developed to predict erodibility variation with time postdisturbance as a function of readily available vegetation cover and surface soil texture data. This will provide ARS the means of predicting impact of conservation by correlating increases in cover attributed to the conservation action with decreases in soil erosion. Significant Activities that Support Special Target Populations: Most of the research conducted through this project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and techniques to sustainably manage Great Basin rangelands. In particular, we work closely with ranchers in Northern California and Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops, over 200 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to manage Great Basin rangelands and reduce soil erosion. The Great Basin Rangelands Research Unit (GBRRU) worked with Mills College in Oakland, California, to recruit two undergraduate students to participate on this project through a fellowship intended to recruit women into careers in the sciences (Jill Barrett Summer Research Fellowship). The students participated in field research in Northern California and Nevada evaluating the impact of climate change on sagebrush demographics. GBRRU worked with the University of Nevada, Reno, and the Paiute tribe, and participated in an outreach program, to describe job opportunities in natural resource management to tribal high school students. Accomplishments 01 Cheatgrass is the most successful weed in the Great Basin. Exotic annual grass invasion into the Great Basin over the last 100 years has resulted in more environmental change than has occurred in the last 10, 000 years. Scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, tested the hypothesis that cheatgrass alters or �engineers� the soil to favor its own invasiveness. Research indicates that cheatgrass increases the availability of soil nitrogen and phosphorus relative to native species. In a multi-state field study on cheatgrass-invaded areas the team found that nitrate-nitrogen levels at depths of 1-2 meters were extremely high compared to controls. The team predicts that declining nitrogen availability in surface soils will hinder the growth of cheatgrass in the long-term and favor growth of perennial grasses, which can exploit deep reserves of nitrogen and lead to rehabilitation of degraded western rangelands. 02 Estimating rate of spread of invasive weeds. Invasions by exotic species are generally described using a logistic growth curve divided into three phases: introduction, expansion, and saturation. ARS researchers in Reno, Nevada, used five datasets ranging from 41 to 86 years in length at five sites in four western states to estimate the expansion of seven exotic species. A greater variety of curve shapes was documented by long-term datasets than those published based on herbaria sampling. Many of the species evaluated were characterized by sporadic spikes and crashes in populations indicating that invasion and rapid expansion of exotic plants is not inevitable. The general lack of fit with current theory is the result of the complex interactions between climate, land management, and succession that drive vegetation change in rangeland environments and provides hope that we can restore degraded rangelands by identifying when invasive species are vulnerable to revegetation efforts. 03 Targeting conservation saves time, money, and land. It is estimated that soil loss costs the United States between $6 and $16 billion dollars every year. ARS researchers in Reno, Nevada, in collaboration with ARS researchers in Boise, Idaho, and Tucson, Arizona, have designed a system to model soil erosion based on quantitative data from Natural Resources Conservation Service-Natural Resources Inventory (NRI) . This modeling approach can be used to predict the effectiveness of alternative management actions and support cost�benefit analyses to optimize return on investments in conservation. This allows for rapid determination of regional needs and identification of where conservation may be most cost-effective in arresting land degradation and enhancing ecosystem services. This same concept can be used to inform policy and to provide a quantitative mechanism to justify targeting to meet specific goals. 04 New ways to estimate precipitation in remote areas of the west. Traditionally, weather stations are often located in cities and not across the vast expanse of open and uninhabited western rangelands making it difficult to forecast drought or develop mitigation plans. Scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, modified wildlife guzzlers (wildlife water developments) as a cost- effective means of improving estimates of climatic parameters in remote Nevada catchments. Field results indicated that water levels in the wildlife guzzler tank measured by pressure transducers corresponded well with measured precipitation events. This study�s results demonstrate that guzzler sites can be augmented with climatic instrumentation at a relatively low cost to improve the quality and density of climate observations, benefitting hydrologists, climatologists, and livestock and wildlife managers. 05 Estimating impacts of drought. ARS researchers in Reno, Nevada, evaluated the spatial variability in green leaf cover of a semi-arid shrub dominated rangeland by comparing field measurements to aerial and satellite imagery. Results indicate that sampling schemes can be defined to reduce sample variance and require fewer sampling locations to achieve a given level of accuracy using satellite imagery before reaching the field site. This would increase cost�effectiveness of individual sample sites and allow more area to be sampled for a fix cost. This technique provides a quantitative means of documenting the health of rangelands and the impact of drought on forage production in western shrub-dominated landscapes. 06 USDA reviews the benefits of conservation on rangelands. USDA spends millions of dollars on conservation each year and has been challenged to define the net benefit of conservation. ARS researchers in Reno, Nevada, in conjunction with University faculty and Natural Resources Conservation Service staff evaluated the conservation benefits of rangeland practices. Together they determined that minimal investment had been made by the rangeland profession in formally assessing conservation practice effectiveness at the appropriate scale and over appropriate time spans. Consequently, conservation practices have seldom been monitored to obtain the ecological and socioeconomic data necessary for a thorough assessment of conservation practice outcomes. This research indicates that new paradigms in the development and support of rangeland monitoring programs must be designed and implemented if Congress desires to increase accountability and cost- effectiveness of conservation programs. 07 Native Animals can assist in rehabilitating western rangelands. Seed harvesting, consumption, and dispersal through caching by granivorous (i.e., seed-eating) desert rodents have profound impacts on specific plant species and on species composition of arid plant communities. Scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, assessed the feasibility of utilizing the seed dispersal services of native animals as a passive restoration strategy. This was successfully tested on a field scale for the first time by broadcasting millet as a �diversionary seed�. The rodents cached and preferentially recovered the diversionary seeds before beginning to consume the less desirable target seeds used in rehabilitation. This passive restoration approach can be used cost-effectively to restore degraded rangelands where traditional approach cannot be applied due to site conditions. 08 Degraded Great Basin rangelands can be rehabilitated with herbicides. Rangelands of the Great Basin are difficult to rehabilitate due to invasive species competition and extreme aridity. In cooperation with stakeholders, including the livestock industry and the mining industry, ARS scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, tested cheatgrass control methods, plant material testing, and post-rehabilitation practices to provide resource managers and private land owners the technologies to rehabilitate rangelands. Our techniques have resulted in 98% control of cheatgrass on our research plots. Moreover, such control has increased the establishment of desirable plant species benefitting forage value, wildlife habitat, and plant community structure. The Nevada Department of Wildlife has documented a 400% increase in the local mule deer populations in these study areas.
Impacts
(N/A)
Publications
- Al-Hamdan, O.Z., Pierson Jr, F.B., Nearing, M.A., Williams, C.J., Stone, J. J., Kormos, P.R., Boll, J., Weltz, M.A. 2013. Risk assessment of erosion from concentrated flow on rangelands using overland flow distribution and shear stress partitioning. Transactions of the ASABE. 56(2):539-548.
- Andreasen, A.M., Stewart, K.M., Longland, W.S., Beckmann, J.P., Forister, M.L. 2012. Identification of source-sink dynamics in mountain lions of the Great Basin. Molecular Ecology 21. DOI: 10.1111/4.1365-294x.2012.05740.x.
- Blank, R.R., Morgan, T.A. 2012. Suppression of Bromus tectorum L. by established perennial grasses: mechanisms-part one. Applied and Environmental Soil Science. DOI: 10.1155/2012/632172.
- Gergans, N., Miller, W., Johnson, D., Sedinger, J., Walker, R., Blank, R.R. 2011. Runoff water quality from a sierran upland forest, transition ecotone, and riparian wet meadow. Soil Science Society of America Journal. 75:1946-1957.
- Grant, N., Saito, L., Weltz, M.A., Walker, M., Stewart, K., Morris, C.E. 2013. Instrumenting wildlife water developments to collect hydrometeorological data in remote western U.S. catchments. Journal of Atmospheric and Ocean Technology. DOI:10.1175/JTECH-D-12-00065.1.
- Hollander, J.L., Vander Wall, S.B., Longland, W.S. 2012. Olfactory detection of caches containing wildland versus cultivated seeds by granivorous rodents. Western North American Naturalist. 72:339-347.
- Mcgwire, K.C., Weltz, M.A., Finzel, J.A., Morris, C.E., Fenstermarker, L., Mcgraw, D. 2012. Multiscale assessment of green leaf area in a semi-arid rangeland with a small unmanned aerial vehicle. International Journal of Remote Sensing. 34(5):1615-1632.
- Morris, C.E., Morris, L., Leffler, J.A., Holifield Collins, C.D., Forman, A.D., Weltz, M.A., Kitchen, S.G. 2013. Using long-term datasets to study exotic plant invasions on rangelands in the western United States. Journal of Arid Environments. 95:65-74.
- Rau, B.M., Tausch, R., Reiner, A., Johnson, D.W., Chambers, J.C., Blank, R. R. 2011. Developing a model framework for predicting effects of woody expansion and fire on ecosystem carbon and nitrogen in a pinyon juniper woodland. Journal of Arid Environments. 76:97-104.
- Spaeth, K., Weltz, M.A., Briske, D., Jolley, L.J., Metz, L.J., Rossi, C.G. 2013. Rangeland CEAP: An assessment of conservation practices. Rangelands. 35:2-10.
- Weltz, M.A., Spaeth, K. 2012. Estimating effects of targeted conservation on nonfederal rangelands. Rangelands. 34(4):35-40.
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): The Integrated Invasive Species Control, Revegetation, and Assessment of Great Basin Rangelands project has two objectives: 1) Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices and 2) Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Approach (from AD-416): The research project is organized into four complementary components: (1) ecology and control of invasive plants, (2) revegetation of degraded rangelands, (3) maintaining and/or enhancing healthy rangelands, and (4) quantifying economic and environmental impacts of management practices at the landscape scale. Experiments will be conducted to understand the seed and seedbed ecology of several native and non-native grasses and shrubs. Herbicides and tillage will be used to vary content of competing vegetation as it affects shrub establishment. Research will be conducted to document ecological processes which control expansion of Western Juniper. Levels of genetic variation of selected plants will be compared between high and low quality ecological conditions sites to determine effects of disturbance on genetic diversity. Rainfall simulators will be used to characterize runoff and soil erosion processes at the scale of a plant community under different manipulative treatments (altered grazing practices, burning, and brush removal) to quantify the hydrologic impact of the conservation practices. The SWAT model will be utilize to evaluate which alternative management scenarios (i.e., a change in vegetation state as represented by changes in canopy and ground cover or vegetation composition by life form) are the most cost effective in achieving the desired environmental benefit. Great Basin Rangelands Research team in Reno, Nevada, has developed techniques to increase the variety and density of desirable native and introduced species when revegetating degraded Great Basin rangelands to suppress cheatgrass and decrease wildfire frequencies. The research team documented this by seeding into areas where cheatgrass had died-off from natural causes and were able to successfully establish 3.9 perennial grasses/ft� compared to 0.6/ft� outside of the die-off zone. Our previous plant materials testing narrowed the species list to 4 wheatgrasses and these species went to seed in their first growing season despite record drought conditions. In an associated study the team found that by disking sites that were still dominated by cheatgrass prior to seeding the resulting action buried the majority of cheatgrass seeds and prevented the cheatgrass seeds from germinating. This resulted in an 83% decrease in cheatgrass densities and a corresponding increase of 244% establishment of desirable seeded species. The combination of these two results was sufficient to decrease fuel loads and significantly reduced the risk of wildfire and provides a variety of treatments depending on site conditions for reducing the impact of cheatgrass on Great Basin Rangelands. We continued ongoing population genetic research with the annual weeds cheatgrass and medusahead using SSR (i.e., microsatellite) markers to characterize populations and identify vulnerabilities that can be exploited when developing treatments to reduce the impact of cheatgrass. Research on animal seed-dispersal vectors of expanding populations of western juniper continued this year, with successful results from a field experiment comparing germination rates of seeds dispersed by birds, by small mammals, and by neither of these seed dispersers. Results clearly indicated that a two-phase dispersal system yields the best seedling recruitment in which birds consume fruits, defecate the seeds, and small mammals then harvest and cache the seeds from the bird droppings. Results of a successful field experiment using �diversionary seeds� to enhance seedling recruitment of Indian ricegrass from seeds cached by small mammals were published in a peer-reviewed article in the journal Restoration Ecology. This was in collaboration with a USGS scientist. The Rangeland Hydrology and Erosion Model tool was used to estimate runoff and erosion at the hillslope scale for over 10,000 sample points in the 17 western states on non-Federal rangelands. Modeling of soil erosion based on quantitative data derived from the rangeland National Resources Inventory (NRI) can be used to predict the effectiveness of alternative management actions and support cost-benefit analysis to optimize return on investment in conservation. The spatially unbiased nature of the rangeland NRI assessment allows for rapid determination of regional needs and identification of where conservation may be most cost- effective in arresting land degradation and enhancing ecosystem services. This same concept can be utilized to inform policy and provide a quantitative mechanism to justify when targeting to meet specific goals. Significant Activities that Support Special Target Populations: Most research conducted through this research project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and techniques to sustainably manage Great Basin rangelands. In particular we work closely with ranchers in Northern California and Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops over 200 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to manage Great Basin rangelands. The Research Unit worked with Mills College in Oakland, California, to recruit two undergraduate students to participate on this project through a fellowship intended to recruit women into careers in the sciences (Jill Barrett Summer Research Fellowship). The students participated in field research in Northern California and Nevada evaluating the impact of climate change on sagebrush demographics. The Research Unit worked with local, middle, and high school students to analyze soil from local train tracks for metals contamination and analyses of ozone pollution on ecosystem processes for their science fair projects. Accomplishments 01 New technology is available to reduce the cost of restoring Great Basin Rangelands. Over 2 billion dollars has been spent fighting wildfires in the western United States and millions more in trying to restore these devastated landscapes over the last decade. Scientists in the Great Basi Rangelands Research Unit in Reno, Nevada, have been working on methods t cost-effectively revegetate these landscapes and reduce the frequency of burning. Our herbicide research on cheatgrass control yielded a 95.8% decrease using Plateau and 98.7% decrease using Landmark which resulted 4.8 perennial grasses/ft� in the Plateau plots and 6.6 perennial grasses/ft� in the Landmark plots despite only receiving 6.3� of precipitation. No perennial grasses established in the control plots and the cheatgrass density and the associated fuel load is a serious problem Our Cheatgrass Control Methods resulted in a cost-effective technique to establish a dense long-lived perennial grass population capable of suppressing cheatgrass, decreasing cheatgrass fuel loads, and subsequent associated wildland fires. 02 Targeting conservation saves money and land. Soil erosion of agricultur lands and sedimentation of the rivers and lakes is one of the largest an persistent environmental problems facing the world. It is estimated that soil loss costs the Unites States over $6 billion dollars every year. Scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, collaboration with ARS scientists in Boise, Idaho, and Tucson, Arizona, have developed the Rangeland Hydrology and Erosion Model (RHEM). The RHE model was used to develop the first national quantitative assessment of soil erosion on western rangelands using data from the NRCS National Resources Inventory program. Results from this assessment were highlight in the USDA Resource Conservation Act and National Conservation Program publications that were delivered to Congress in support of the 2012 Farm Bill and document how targeting conservation can save money and land. 03 Rodents can be utilized to restore Great Basin environments. Seed harvesting, consumption, and dispersal through caching by granivorous (i , seed-eating) desert rodents have profound impacts on specific plant species and on species composition of arid plant communities. The feasibility of utilizing the seed dispersal services of native animals a a passive restoration strategy was successfully tested at a field scale for the first time by broadcasting millet as a �diversionary seed� over ha plots in areas where heteromyid rodents typically cache Indian ricegrass seeds in abundance. Under these circumstances, rodents cached and preferentially recovered the preferred diversionary seeds before beginning to consume the less desirable target seeds. Consequently, more target seeds were available for emergence as seedlings using this passiv restoration scheme. We documented this enhanced seedling recruitment in recently published article in Restoration Ecology. 04 Cheatgrass density does impact establishment of native species used to restore degraded Great Basin rangelands. Surprisingly little is known about how climate change coupled with cheatgrass invasion will affect th long-term persistence of sagebrush populations. ARS researchers in Reno, Nevada, continue to measure population-level performance of sagebrush wh grown in competition with low and high densities of cheatgrass under different climate change scenarios across an elevation gradient. The research indicates that lower elevation populations of sagebrush will decline in the face of climate change and cheatgrass invasion. Higher elevation populations and sites with higher annual precipitation, have greater resilience and resistance to invasion by cheatgrass and are like to persist and continue to provide critical ecosystem services. 05 Introduced plants can provide valuable ecosystem services. ARS scientis in Reno, Nevada, and Logan, Utah, have been investigating the risks and benefits of the introduced plant �Immigrant� forage kochia (Bassia prostrata, formerly Kochia prostrata). This perennial semi-evergreen hal shrub averages 1 to 3 feet in height and can grow in habitats that recei 5 to 27 inches of annual precipitations, and survives the extreme temperatures (-25 to 104�F) found in arid deserts. ARS scientists have determined that forage kochia is excellent winter forage, especially for livestock and wintering mule deer herds; is competitive with cheatgrass; can slow the spread of wildfires; and is widely adapted to soils found across semi-arid cold deserts of the western United States. Research conducted over the last 25+ years by the USDA-ARS scientists at Logan, Utah, and Reno, Nevada, have documented that forage kochia has shown no evidence that it is invasive and will spread outside of original plantin area into established plant communities. Forage kochia has proven to be valuable tool in revegetating disturbed rangelands destroyed by cheatgra invasion and repeated wildfires and prevents soil erosion. 06 Starving cheatgrass of essential nutrients may prevent invasions and lea to opportunities for successful restoration of Great Basin rangelands. Cheatgrass is an exotic annual grass causing ecosystem degradation acros the entire western United States. ARS scientists in Reno, Nevada, have investigated potential mechanisms by which the perennial grass, crested wheatgrass, can be used to suppress cheatgrass. Research focused on understanding the role of nitrogen in the susceptibility of the site to invasion to cheatgrass. Scientists found that crested wheatgrass does no suppress cheatgrass by controlling extractable Nitrogen (N) below a threshold level. Rather, scientists hypothesize that it may limit the conversion of ammonium-N to nitrate-N and thereby reduce nitrate-N availability to cheatgrass and its ability to invade and dominate a site
Impacts
(N/A)
Publications
- Blank, R.R., Morgan, T.A. 2012. Mineral nitrogen in a crested wheatgrass stand: implications for suppression of cheatgrass. Rangeland Ecology and Management. 65:101-104.
- Finzel, J.A., Seyfried, M.S., Weltz, M.A., Kiniry, J.R., Johnson, M.V.V., Launchbaugh, K.L. 2012. Indirect measurement of leaf area index in sagebrush-steppe rangelands. Rangeland Ecology and Management. 65:208-212.
- Clements, D.D., Waldron, B.L., Mccuin, G. 2011. Immigrant forage kochia: A closer look at this rangeland plant. The Progressive Rancher. 5(8):16-17.
- Al-Hamdan, O.Z., Pierson Jr, F.B., Nearing, M.A., Stone, J.J., Williams, C. J., Moffet, C.A., Kormos, P.R., Boll, J., Weltz, M.A. 2012. Characteristics of concentrated flow hydraulics for rangeland ecosystems: Implications for hydrologic modeling. Earth Surface Processes and Landforms. 37(2):157-168.
- Longland, W.S., Ostoja, S.M. 2012. Ecosystem services from keystone species: diversionary seeding and seed-caching desert rodents can enhance Indian ricegrass seedling establishment. Restoration Ecology. DOI: 10. 1111/j.1526-100X.2012.00895.x.
- Al-Hamdan, O.Z., Pierson Jr, F.B., Nearing, M.A., Williams, C.J., Stone, J. J., Kormos, P.R., Boll, J., Weltz, M.A. 2012. Concentrated flow erodibility for physically-based erosion models: temporal variability in disturbed and undisturbed rangelands. Water Resources Research. DOI: 10. 1029/2011WR011464.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The Integrated Invasive Species Control, Revegetation, and Assessment of Great Basin Rangelands project has two objectives: 1) Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices and 2) Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Approach (from AD-416) The research project is organized into four complementary components: (1) ecology and control of invasive plants, (2) revegetation of degraded rangelands, (3) maintaining and/or enhancing healthy rangelands, and (4) quantifying economic and environmental impacts of management practices at the landscape scale. Experiments will be conducted to understand the seed and seedbed ecology of several native and non-native grasses and shrubs. Herbicides and tillage will be used to vary content of competing vegetation as it affects shrub establishment. Research will be conducted to document ecological processes which control expansion of Western Juniper. Levels of genetic variation of selected plants will be compared between high and low quality ecological condition sites to determine effects of disturbance on genetic diversity. Rainfall simulators will be used to characterize runoff and soil erosion processes at the scale of a plant community under different manipulative treatments (altered grazing practices, burning, and brush removal) to quantify the hydrologic impact of the conservation practices. The SWAT model will be utilized to evaluate which alternative management scenarios (i.e., a change in vegetation state as represented by changes in canopy and ground cover or vegetation composition by life form) are the most cost effective in achieving the desired environmental benefit. Great Basin Rangelands Research team has developed techniques to increase the variety and density of desirable native and introduced species when revegetating degraded Great Basin rangelands to suppress cheatgrass and decrease wildfire frequencies. The research team documented that by disking the site prior to seeding the resulting action buried the majority of cheatgrass seeds and prevented the cheatgrass seeds from germinating. This resulted in an 83% decrease in cheatgrass densities and a corresponding increase of 244% in establishment of desirable seeded species. The combination of these two results were sufficient to decrease fuel loads and significantly reduced the risk of wildfire. The Rangeland Hydrology and Erosion Model tool was used to estimate runoff and erosion at the hillslope scale for over 10,000 sample points in the 17 western states on non-Federal rangelands. National average annual erosion rate on non-Federal rangeland is approximately 1.5 tons per year. Nationally 20% of non-Federal rangelands generate over 65% of the average annual soil loss. Over 29 million hectors 18% of the non- Federal rangelands might benefit from treatment to reduce soil loss to a sustainable level. The release of this new erosion tool now provides land managers a cost-effective tool for targeting conservation on the most vulnerable lands. Seed dispersal and seedling recruitment studies in western juniper populations were initiated to document pathways of recruitment of this invasive conifer. At least 6 small mammal species and 5 bird species have been found to feed on juniper berries and/or seeds. Results to date indicate that most birds consume juniper berries and defecate seeds intact and that all small mammal species (except for one) tend to avoid berries and take mainly seeds that are defecated by birds. Preliminary analysis supports hypothesis that juniper seedling recruitment occurs through �diplochory� or two sequential seed dispersal agents � in this case consumption of fruit by birds followed by harvesting and caching of bird-defecated seeds by rodents. Methods designed to reduce invasion by western juniper trees must account for this recruitment action in developing restoration plans. Great Basin Rangelands Research team documented that soil type mediates interactions between an invasive plant and its biocontrol agents. This study documented the need to explicitly consider soil type when selecting release sites for new agents � an agent that is minimally effective in one area may be more effective in another based on soil-plant interactions. A recently approved agent has been generally considered a disappointment as a biocontrol agent but this work shows that in areas where starthistle has invaded serpentine soils it is expected to be effective. This is especially important as serpentine soils are generally areas of critical concern as they host numerous endangered species and use of this biocontrol agent to reduce starthistle will have great conservation impact and help to recover these impacted sites in a cost-effective manner. Significant Activities that Support Special Target Populations The Research Unit worked with University of Nevada, Reno to host an annual workshop on jobs in natural resources for the Paiute tribe high school students. During the one week summer workshop the high school students were provided an overview of jobs in natural resources on the first day and a tour of ARS and University of Nevada, Reno research facilities. On each of the following days the students were hosted by a scientist who took them to the field to demonstrate different techniques to measure abiotic and biotic parameters used to define watershed health within the Truckee River basin. Most research conducted through this research project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and sustainably managing Great Basin rangelands. In particular we work closely with ranchers in Northern California and Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops over 500 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to manage Great Basin rangelands. Accomplishments 01 Reducing the cost in restoring Great Basin Rangelands. Over 2 billion dollars have been spent fighting wildfires in the western United States and millions more in trying to restore these devastated landscapes over the last decade. Scientists in the Great Basin Rangelands Research Unit in Reno, Nevada, have been working on methods to cost-effectively revegetate these landscapes and reduce the frequency of burning. The scientific team has documented that by disking the site prior to seeding the resulting action buried the majority of cheatgrass seeds and prevent the cheatgrass seeds from germinating. This resulted in an 83% decrease in cheatgrass densities and a corresponding increase of 244% establishme of desirable seeded species. The combination of these two results was sufficient to decrease fuel loads, significantly reduced the risk of wildfire, increase forage availability for wildlife and domestic livesto and reduced the cost of revegetating a site by approximately 50%. 02 New technique predicts impact of invasive weed control saving time and money. Weed control costs time and money. A new tool was developed that allows land manager to predict the impact of a biocontrol agent on weed density, spread rate and population growth rate. This tool allows land managers to predict how a biocontrol agent will impact an invasive plant over temporal and spatial scales that are not otherwise possible. It can show land managers that an agent may be capable of reducing one measure invader success (e.g., density), while having no impact on others (e.g., the rate at which it is spreading into uninvaded areas or its persistenc over the long-term). With this new information, land managers can assess if current invasive weed control strategies will work or will they need augment their control strategies with additional weed control practices. Adoption of this new approach in predicting invasive species control should improve efficacy of control techniques and reduce cost by minimizing number of ineffective practices deployed. 03 Tools to target conservation saving money and land. Soil erosion of agricultural lands and sedimentation of the rivers and lakes is one of t largest and persistent environmental problems facing the world. It is estimated that soil loss costs the Unites States over $6 billion dollars every year. Scientists in the Great Basin Rangelands Research Unit in Re Nevada, in collaboration with ARS scientists in Boise, Idaho, and Tucso Arizona, have developed a new soil prediction tool for rangelands. This tool allows land managers to predict long-term soil loss and soil loss from individual storms. This new tool provides a method for land manage to predict where erosion will occur and evaluate alternative conservatio practices to assess possible benefits before soil degradation occurs. Th tool has been adopted by the Natural Resources Conservation Service and being used to evaluate existing conservation programs and how they can b enhanced and improved deliver of conservation in a more cost-effective manner by targeting areas of concern.
Impacts
(N/A)
Publications
- Rau, B.M., Johnson, D.W., Blank, R.R., Lucchesi, A., Caldwell, T.G., Schupp, E.W. 2011. Transition from sagebrush steppe to annual grass (Bromus tectorum): influence on belowground carbon and nitrogen. Rangeland Ecology and Management. 64:139-147.
- Crampton, L.H., Longland, W.S., Murphy, D.D., Sedinger, J.S. 2011. Food abundance determines distribution and density of a frugivorous bird across seasons. Oikos. 120:65-76.
- Johnson, M., Finzel, J.A., Spanel, D.A., Weltz, M.A., Sanchez, H., Kiniry, J.R. 2011. The rancher's ALMANAC. Rangelands. 33(2):10-16.
- Johnson, B., Johnson, D., Chambers, J., Blank, R.R. 2011. Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.). Plant and Soil. 341:437-445.
- Rau, B.M., Johnson, D.W., Blank, R.R., Tausch, R.J., Roundy, B.A., Miller, R.F., Caldwell, T.G., Lucchesi, A. 2011. Woodland expansion�s influence on belowground carbon and nitrogen in the Great Basin U.S.. Journal of Arid Environments. 75:827-835.
- Rau, B.M., Melvin, A.M., Johnson, D.W., Goodale, C.L., Blank, R.R., Fredriksen, G., Miller, W.W., Murphy, J.D., Todd, Jr., D.E., Walker, R.F. 2011. Revisiting soil carbon and nitrogen sampling: quantitative pits versus rotary cores. Soil Science. 176:273-279.
- Boursiac, Y., Lee, S., Romanowsky, S., Blank, R.R., Sladek, C., Chung, W., Harper, J. 2010. Disruption of the vacuolar calcium-ATPases in arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway. Journal of Plant Physiology. 154:1158-1171.
- Mazzola, M.B., Chambers, J.C., Blank, R.R., Pyke, D.A., Schupp, E.W., Allcock, K.G., Doescher, P.S., Nowak, R.S. 2010. Effects of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by Bromus tectorum. Biological Invasions. 13:513-526.
- Blank, R.R., Morgan, T.A. 2010. Influence of livestock grazing, floodplain position, and time on soil nutrient pools in a Sierra-Nevada montane meadow. Soil Science. 175:293-302.
- Nearing, M.A., Wei, H., Stone, J.J., Pierson, Jr. F.B., Spaeth, K., Weltz, M.A., Flanagan, D.C., Hernandez, M. 2011. A rangeland hydrology and erosion model. Transactions of the ASABE. 54(3):1-8.
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) The Integrated Invasive Species Control, Revegetation, and Assessment of Great Basin Rangelands project has two objectives: 1) Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices and 2) Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Approach (from AD-416) The research project is organized into four complementary components: (1) ecology and control of invasive plants, (2) revegetation of degraded rangelands, (3) maintaining and/or enhancing healthy rangelands, and (4) quantifying economic and environmental impacts of management practices at the landscape scale. Experiments will be conducted to understand the seed and seedbed ecology of several native and non-native grasses and shrubs. Herbicides and tillage will be used to vary content of competing vegetation as it affects shrub establishment. Research will be conducted to document ecological processes which control expansion of Western Juniper. Levels of genetic variation of selected plants will be compared between high and low quality ecological conditions sites to determine effects of disturbance on genetic diversity. Rainfall simulators will be used to characterize runoff and soil erosion processes at the scale of a plant community under different manipulative treatments (altered grazing practices, burning, and brush removal) to quantify the hydrologic impact of the conservation practices. The SWAT model will be utilize to evaluate which alternative management scenarios (i.e., a change in vegetation state as represented by changes in canopy and ground cover or vegetation composition by life form) are the most cost effective in achieving the desired environmental benefit. Replaces 5325-11220-005-00D (2/09). The USDA team working on CEAP has developed a new process based model for assessing soil erosion rates on rangelands. The Rangeland Hydrology and Erosion Model (RHEM) was developed based exclusively on data collected from rangeland erosion experiments. RHEM is designed to use data that is routinely collected by range managers and the model can be accessed through the internet to develop fast and efficient recommendation on which conservation practices are the most cost efficient for achieving a targeted reduction in soil loss. RHEM has been adopted by the Natural Resources Conservation Service for use in calculating runoff and soil erosion at the hillslope scale. Efforts are currently underway to apply RHEM at 10,000 NRCS National Resource Inventory (NRI) sampling sites as a means of producing the first national assessment of soil loss on rangelands for the USDA Resource Conservation Assessment report due to Congress in December 2010. Research was initiated to focus on the potential of using native annual forbs to increase establishment of early successional native perennial species in cheatgrass invaded rangelands. Species that germinate in the fall, with cheatgrass, are able to accumulate biomass and establish roots that might provide a competitive advantage relative to spring germinators. Native annual species that were observed to be part of the post- disturbance flora in Wyoming sagebrush plant communities in western Nevada were selected for evaluation. The results of this research will lead into future work focusing on the facilitative effects of early seral grass and forb species on the successful restoration of desired shrubs and longer-lived perennial grasses and forbs, into disturbed plant communities. This unit has collected the last phase of data that will lead to guidelines to revegetate habitats disturbed by wildfire. The data clearly shows that rangelands that burn are much more likely to be successfully revegetated the 1st fall following the wildfire than waiting until the 2nd year. Using specific plant species is also necessary to compete with and suppress cheatgrass densities. As part of the Sagebrush Steppe Treatment Evaluation Project, ARS scientists have quantified soil carbon stocks and the effect of several restoration treatments on these stocks in several sagebrush and pinyon-juniper ecosystems in Idaho, Oregon, Utah, and Nevada. Data are presently being analyzed and should determine the potential of these ecosystems to store anthropogenic carbon dioxide. Juniper berry removal experiments at 3 northern California sites were initiated to investigate seed dispersal and seedling recruitment in western juniper populations. Juniper berry production was estimated for all trees on 1-ha study plots at each of these sites, and a new study was initiated to identify insect seed predators and quantify their effects on juniper seed viability. Annual small mammal trapping and bird surveys were established at each site and automated wildlife cameras were deployed at 2 sites. This has resulted in identification of at least 5 small mammal and 4 bird species that consume juniper berries and potentially disperse seeds. Significant Activities that Support Special Target Populations The Research Unit worked with the University of Nevada at Reno to host the third annual workshop on jobs in natural resources for Piute tribe high school students. During the one week summer workshop the high school students were provided an overview of jobs in natural resources on the first day and a tour of ARS and University of Nevada at Reno research facilities. On each of the following days the students were hosted by a scientist who took them to the field to demonstrate different techniques to measure abiotic and biotic parameters used to define watershed health within the Truckee river basin. Most research conducted through this research project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and sustainably managing Great Basin rangelands. In particular we work closely with ranchers in Northern California and Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops over 500 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to mange Great Basin rangelands. Accomplishments 01 Reduction of cheatgrass and development of potential new agricultural products. Scientists in the Exotic and Invasive Weeds Research Unit in Reno, Nevada conducted basic research on the possibility of using seeds from the invasive annual grass cheatgrass as a new grain for use in producing food and beverages. Preliminary work was initiated on appropriate techniques to harvest, process, and malt cheatgrass as a gra source for brewing beer. The seeds were collected as part of a project mechanically remove the annual grass seed source and reduce the cheatgra sandbank so that native plant species can be successfully reestablished. If harvested properly, it can reduce fuel loads by creating green stripe thereby reducing the probability of catastrophic wildfires. Removal of cheatgrass seeds, a major invasive annual grass in the intermountain wes has the potential to aid in ecosystem restoration. The beer produced by fermentation of cheatgrass seeds has been judged to be of good quality a could increase the economic viability of cheatgrass-infested ecosystems. This research successfully demonstrated that cheatgrass seeds are a viab source of grain for use in agricultural products and that commercial vendor would purchase the seed if available. No further work is planned this time as it has been successfully demonstrated that cheatgrass seeds are a viable protein source in producing agricultural food products. 02 Introduced plants may help reduce cheatgrass in the Great Basin. Scientists in the Exotic and Invasive Weeds Research Unit in Reno, Nevad have documented that crested wheatgrass can effectively suppress cheatgrass. The team tested the hypothesis that crested wheatgrass reduc available mineral soil N to levels below which cheatgrass is competitive Relative to other ecosystems tested, soil beneath crested wheatgrass doe not have appreciably lower mineral N. Surprisingly, the molar proportion of ammonium-N in the total mineral pool is quite high in the tested crested wheatgrass ecosystem, averaging 84% throughout the year. Further studies are underway to reduce the competitiveness of cheatgrass. 03 Small mammals do heavy lifting in restoring Great Basin rangelands. Scientists in the Exotic and Invasive Weeds Research Unit in Reno, Nevad have found that desert rodents can have profound impacts on specific pla species and on species composition of arid plant communities. Buried, scattered seed caches made by rodents accounted for 95% of seedling production of the native grass, Indian ricegrass which is a critical forage resource for livestock and wildlife. These animals cache seeds ne the ground surface with the full intention of returning during seasons o seed shortages to later consume the cached seeds. Only seeds that escape this subsequent re-harvesting for consumption can germinate the followin spring. It is possible to enhance the beneficial effects of a seed-cachi rodent species of native plant species by providing inexpensive commercially available, ÿ¿diversionaryÿ¿ seeds that are highly desirable t the rodents. Rodents would then cache both seed types but preferentially recover the preferred diversionary seeds before beginning to consume the less desirable native plant species seeds. Consequently, more native pla seeds are available for emergence as seedlings using this passive and inexpensive restoration scheme. 04 Reducing the cost in restoring Great Basin Rangelands. Scientists in th Exotic and Invasive Weeds Research Unit in Reno, Nevada have developed techniques of increasing the success of restoration/revegetation practic of cheatgrass invaded rangelands. These techniques on average cost $119 75/ac during the first year. However, if treatments are delayed until t second year costs goes up to $207.95 and success is significantly less. The long term result would be healthy rangelands.
Impacts
(N/A)
Publications
- Caldwell, T.G., Johnson, D.W., Miller, W.W., Qualls, R.G., Blank, R.R. 2009. Prescription Fire and Anion Retention in Tahoe Forest Soils. Soil Science. 174:594-600.
- Clements, C.D., McCuin, G., Shane, R.S., McAdoo, K., Harmon, D.N. 2009. Wildfire Restoration and Rehabilitation: Triage in Pursuit of Resilience. Rangelands. 31(3):30-35.
- Blank, R.R., Young, J.A. 2009. Plant-Soil Relationships of Bromus tectorum L.: Interactions among Labile Carbon Additions, Soil Invasion Status, and Fertilizer. Applied and Environmental Soil Science. Volume 2009:1-7. Article ID 929120.
- Rau, B.M., Tausch, R., Reiner, A., Johnson, D.W., Chambers, J.C., Blank, R. R., Lucchesi, A. 2010. Influence of Prescribed Fire on Ecosystem Biomass, Carbon, and Nitrogen in a Pinyon Juniper Woodland. Rangeland Ecology and Management. 63:197-202.
- Blank, R.R. 2009. Intraspecific and interspecific pair-wise seedling competition between exotic annual grasses and native perennials: Plant- soil relationships. Plant and Soil. 326:331-343.
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) The Integrated Invasive Species Control, Revegetation, and Assessment of Great Basin Rangelands project has two objectives: 1) Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices and 2) Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Approach (from AD-416) The research project is organized into four complementary components: (1) ecology and control of invasive plants, (2) revegetation of degraded rangelands, (3) maintaining and/or enhancing healthy rangelands, and (4) quantifying economic and environmental impacts of management practices at the landscape scale. Experiments will be conducted to understand the seed and seedbed ecology of several native and non-native grasses and shrubs. Herbicides and tillage will be used to vary content of competing vegetation as it affects shrub establishment. Research will be conducted to document ecological processes which control expansion of Western Juniper. Levels of genetic variation of selected plants will be compared between high and low quality ecological conditions sites to determine effects of disturbance on genetic diversity. Rainfall simulators will be used to characterize runoff and soil erosion processes at the scale of a plant community under different manipulative treatments (altered grazing practices, burning, and brush removal) to quantify the hydrologic impact of the conservation practices. The SWAT model will be utilize to evaluate which alternative management scenarios (i.e., a change in vegetation state as represented by changes in canopy and ground cover or vegetation composition by life form) are the most cost effective in achieving the desired environmental benefit. Replaces 5325-11220-005-00D (2/09). Significant Activities that Support Special Target Populations The USDA team working on CEAP has developed a new process based model for assessing soil erosion rates on rangelands. The Rangeland Hydrology and Erosion Model (RHEM) is being developed based exclusively on data collected from rangeland erosion experiments, and is designed to use data that is routinely collected by range managers. RHEM will be used to calculate runoff and erosion at the hillslope scale and will replace the Revised Universal Soil Loss Equation on grazing lands. Efforts are currently underway to apply RHEM to NRCS National Resource Inventory (NRI) sampling sites as a means of producing the first national assessment of soil loss on rangelands. In cooperation with University of Nevada, we conducted a field study that quantified above- and below-ground carbon stocks in pinyon-juniper ecosystems treated with prescribed fire. Data clearly showed that prescribed burning caused immediate increases in surface soil C and N concentration, but over longer periods of time no statistically detectable change in soil C or N content occurred from burning. We also completed a study on 8 sites in northern Nevada and northeastern California in which individual and combinations of Fe, Cu, Zn, Mn, Fe, Ni, and Ag were applied to decrease enzyme activities associated with N- mineralization. We then monitored cheatgrass density and soil nutrient availability of N. At all sites, micronutrient additions have not decreased N availability or cheatgrass density relative to control plots. In another cheatgrass study, plants were collected as both green plants and mature seed at 8 different field sites. Red brome samples were also collected at 2 of these sites and one additional site. Samples are being shared with the US Forest Service�s Shrub Science Laboratory (Provo, UT) for collaborative research. DNA extractions and analyses have been completed for samples collected in 2008 and are ongoing for green plant Three study sites were identified in northern California for long-term study of the roles of seed dispersal and seedling recruitment in the ongoing expansion of western juniper woodlands. All juniper trees on 2 of these sites were cored for aging in 2008, and tree coring is currently ongoing at the third site. Collected cores have been prepared and aged in the lab. Juniper berry production was estimated for all trees at each site during the Fall of 2008. We conducted small mammal trapping and bird surveys and deployed automated wildlife cameras to identify potentially important seed dispersing animals. Small mammal and bird species that consume juniper berries and disperse seeds have been identified at one study site using motion-activated trail monitoring camera systems. We initiated a seed trap study at the new sites to begin quantifying levels of seed predation in western juniper. The rate at which juniper berries fall from trees was quantified at 2 field sites using paired seed traps placed under berry-laden trees. Significant Activities that Support Special Target Populations The Research Unit worked with University of Nevada at Reno to develop a workshop on jobs in natural resources for Piute tribe high school students. During the 1 week summer workshop the high school students were provided an overview of jobs in natural resources on the first day and a tour of ARS and University of Nevada at Reno research facilities. On each of the following days the students were hosted by a scientist who took them to the field to demonstrate different techniques to measure abiotic and biotic parameters used to define watershed health within the Truckee river basin. Most research conducted through this research project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and sustainably managing Great Basin rangelands. In particular we work closely with ranchers in central Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops over 500 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to mange Great Basin rangelands.
Impacts
(N/A)
Publications
- Schierenbeck, K.A., Ellstrand, N.C. 2008. Hybridization and Evolution of Invasiveness in Plants and Other Organisms. Biological Invasions 11:1093- 1105.
- Weltz, M.A., Jolley, L., Nearing, M.A., Stone, J.J., Goodrich, D.C., Pierson Jr, F.B., Speath, K., Kiniry, J.R., Arnold, J.G., Bubenheim, D., Hernandez, M., Wei, H. 2008. Assessing the benefits of grazing land conservation practices. Journal of Soil and Water Conservation. 63:214- 217.
- Duriancik, L., Bucks, D., Dobrowolski, J.P., Drews, T., Eckles, S.D., Jolley, L., Kellogg, R.L., Lund, D. Makuch, J.R., O'Neil, M.P., Rewa, C.A., Walbridge, M.R., Parry, R., Weltz, M. 2008. The first five years of the Conservation Effects Assessment Project. Journal of Soil and Water Conservation. 63:185-197.
- Longland, W.S., Aten, M., Swartz, M., Kulpa, S. 2009. Who�s Eating the Flowers of a Rare Western Nevada Range Plant?. Rangelands 31:26-30.
- Rau, B.M., Johnson, D.W., Blank, R.R., Chambers, J.C. 2009. Soil carbon and nitrogen in a Great Basin pinyon-juniper woodland: Influence of vegetation, burning, and time. Journal of Arid Environments. 73(2009):472- 479.
- Goergen, E., Chambers, J., Blank, R.R. 2009. Effects of Water and Nitrogen Availability on Nitrogen Contribution by the Legume, Lupinus argenteus Pursh. Applied Soil Ecology. 42:200-208.
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