R. Blew - S. M. Stoller Corporation
The Idaho National Laboratory (INL) Site was designated as a National Environmental Research Park (NERP) in 1975. The NERP program was established in response to recommendations from citizens, scientists, and members of Congress to set aside land for ecosystem preservation and study. This has been one of the few formal efforts to protect land on a national scale for ecosystem preservation, research, and education. In many cases, these protected lands became the last remaining refuges of what were once extensive natural ecosystems.
There are five basic objectives guiding activities on the Research Parks. They are to:
The NERPs provide rich environments for training researchers and introducing the public to the ecological sciences. They have been used to educate grade school and high school students and the general public about ecosystem interactions at U.S. Department of Energy (DOE) sites; train graduate and undergraduate students in research related to site-specific, regional, national, and global issues; and promote collaboration and coordination among local, regional, and national public organizations, schools, universities, and federal and state agencies.
Establishment of NERPs was not the beginning of ecological research at
Federal laboratories. Ecological research at the INL Site began in 1950 with the
establishment of the long-term vegetation transect study. This is perhaps DOE’s
oldest ecological data set and one of the most significant vegetation datasets
for the sagebrush steppe ecosystem. Other long-term studies conducted on the
Idaho NERP include the reptile monitoring study initiated in 1989, which is the
longest continuous study of its kind in the world; as well as the protective cap
biobarrier experiment initiated in 1993, which evaluates the long-term
performance of evapotranspiration caps and biological intrusion barriers.
Ecological research on the NERPs is leading to better land-use planning,
identifying sensitive areas on DOE sites so that restoration and other
activities are compatible with ecosystem protection and management, and
increased contributions to ecological science in general.
The Idaho NERP provides a coordinating structure for ecological research and information exchange at the INL. The Idaho NERP facilitates ecological research on the INL by attracting new researchers, providing background data to support new research project development, and providing logistical support for assisting researcher access to the INL. The Idaho NERP provides infrastructure support to ecological researchers through the Experimental Field Station and museum reference collections. The Idaho NERP tries to foster cooperation and research integration by encouraging researchers using the INL to collaborate, develop interdisciplinary teams to address more complex problems, and encourage data sharing, and by leveraging funding across projects to provide more efficient use of resources. The Idaho NERP has begun to develop a centralized ecological database to provide an archive for ecological data and facilitate retrieval of data to support new research projects and land management decisions. The Idaho NERP can also be a point of synthesis for research results that integrates results from many projects and disciplines and provides analysis of ecosystem-level responses. The Idaho NERP also provides interpretation of research results to land and facility managers to support the National Environmental Policy Act (NEPA) process natural resources management, radionuclide pathway analysis, and ecological risk assessment.
The following sections describe ecological research activities that took
place at the Idaho NERP during 2006.
Scott Cambrin, Graduate Student, Herpetology Laboratory, Department of
Biological Sciences, Idaho State University, Pocatello, ID
Charles R. Peterson, Professor, Herpetology Laboratory, Department of Biological
Sciences, Idaho State University, Pocatello, ID
Idaho State University Graduate Student Research and Scholarship Committee
U.S. Department of Energy Idaho Operations Office
Many amphibian and reptile species have characteristics that make them sensitive environmental indicators. The main research goal of this project is to provide indicators of environmental health and change by monitoring the distribution and population trends of amphibians and reptiles on the INL. This information is important to the DOE for several reasons:
The main objective of this project is to monitor amphibian and reptile distribution on the INL. Specific objectives for 2006 included the following:
Specific accomplishments for 2006 include the following:
An M.S. thesis is expected to be completed in 2007 by S. Cambrin based on this work. Monitoring herpetofauna is one part of the wildlife monitoring task in the Environmental Surveillance, Education and Research program and is expected to continue.
William H. Clark, Orma J. Smith Museum of Natural History, Albertson College
of Idaho, Caldwell, ID
Paul E. Blom, Division of Entomology, Dept. of Plant, Soil, and Entomological
Sciences, University of Idaho, Moscow, (Present affiliation: USDA-ARS, Prosser,
WA)
U.S. Department of Energy Idaho Operations Office
Orma J. Museum of Natural History, Albertson College of Idaho
W. Clark and P. Blom
The need for basic information on INL’s ant fauna became evident during the course of other waste management-related research at the INL. With this realization an annotated survey of INL ants was initiated in 1986. The resulting field and laboratory work spanned 20 years and culminated in a monograph published in Sociobiology (Clark, W.H., and P.E. Blom. 2007).
Many invertebrates, including ants, tunnel and nest in soils. Because of these habits they are potentially important at the INL where they may tunnel into and disturb buried waste. Ants are very important components of the desert ecosystem based on their distribution, habitat preferences, food habits, and relative abundance. For these reasons the ant taxa present at the INL were investigated. A cursory survey of the ants at the site was published in 1971 which reported 22 species. A more thorough examination was needed.
Our research in the northeastern portion of the Snake River Plain at the INL from 1986 to 1996 produced thousands of ant collections, of which 1,115 (mostly nest series) are used in this manuscript. These collections contained 46 species in 19 genera from three subfamilies. This more than doubles the number of the species previously reported from the INL. Of the ant species found, 18 (39 percent) are considered rare on the site, 12 (26 percent) are present but not common, 11 (24 percent) are common, and only five (11 percent) are found to be abundant. All but three ant genera known for the state of Idaho can be found at the INL. Additionally, four species collected during this research are reported from Idaho for the first time: Liometopum luctuosum, Formica gynocrates, Formica spatulata, and Myrmica sp. (a new species).
Formicoxenus diversipilosus was only found within the nests of the Formica rufa group, Formica planipilis and Formica subnitens. These represent new host records for the species. Formicoxenus hirticornis was found nesting with the thatch ants: Formica planipilis, Formica ciliata, Formica laeviceps, and Formica subnitens, all of which represent new host records for this species.
The goal of this investigation is to provide a more thorough survey of the INL ant fauna for both biodiversity and waste management purposes. The objectives were: (1) to produce an updated checklist of the INL ants, (2) to summarize the pertinent published information and literature on the INL ants, and (3) to present keys, distribution maps, illustrations, and ecological information on each taxon. This information should allow for the identification of ants encountered at the site and be of use to ecologists and other scientists working at the site. Much new information concerning the biology, ecology, and natural history of many of the species found on INL is presented. The literature on the ants of the INL is summarized. This work paves the way for more detailed ecological studies of the INL ant fauna.
Christopher L. Jenkins, Graduate Student, Department of Biological Sciences,
Idaho State University, Pocatello ID
Charles R. Peterson, Professor, Herpetology Laboratory, Department of Biological
Sciences, Idaho State University, Pocatello, ID
U.S. Department of Energy Idaho Operations Office
INL Education Outreach Program (Bechtel)
Idaho State University (CERE Lab and Graduate Research Committee)
Bureau of Land Management
Idaho Department of Fish and Game
This project was designed to assess the impact of landscape disturbance on western rattlesnakes by examining trophic interactions among habitat, small mammals, and snakes. The synergistic effect of livestock grazing, invasive plants and fire is changing sagebrush steppe ecosystems in the Upper Snake River Plain. It is hypothesized that this phenomenon is affecting the prey base of top-level predators in the system. The main research goal is to determine if changes in habitat are altering prey availability and subsequently life history characteristics of western rattlesnakes.
Information from this project is important to the DOE for several reasons:
The overall goal of this project is to determine if current landscape patterns
in habitat and prey on the INL are influencing rattlesnake life histories.
Specific objectives included the following:
This research was conducted as part of a doctoral program and has been completed.
Widespread disturbance in sagebrush steppe ecosystems is threatening Great Basin rattlesnake populations. The sagebrush steppe ecosystem is experiencing a variety of disturbances including mining, human development, livestock grazing, invasive plants, and changing fire regimes. Great Basin rattlesnakes (Crotalus oreganus lutosus) are capital breeding snakes that acquire energy over multiple years for reproduction. Disturbances in sagebrush steppe may be influencing rattlesnake reproductive output by limiting the amount of energy (i.e., food) they can acquire during the active season. The goal of this dissertation was to determine to what extent and how disturbance influences populations of Great Basin rattlesnakes.
The following were sampled: substrate, vegetation, small mammals, and operative temperatures. Mark-recapture; radio telemetry; and a common garden were conducted on rattlesnakes. These studies occurred at three large overwintering complexes (CRAB, CINB, and RCAV as defined in Section 9.1) on the INL. The INL is a DOE nuclear research facility. Portions of the INL are grazed by livestock and some fires have occurred in the area.
Results suggest that broad patterns in landscape disturbance are indirectly influencing rattlesnake reproduction by altering prey availability. First, a significant microgeographic variation in reproduction was found. Specifically, the CRAB Butte population had lower reproductive output due to lower body condition, slower growth, later ages to maturity, longer intervals between pregnancies and lower fecundity. Second, an approach was developed to determine the factors influencing reproduction that links broad scale landscape disturbance such as grazing and fire to rattlesnake ecology through a series of trophic interactions. Finally, using this approach, it was determined that prey availability was higher in a landscape with less disturbance and greater precipitation. Snakes using areas with higher prey availability meandered more during movements and gained less weight. When comparing two of the sites, CRAB had more landscape disturbance, lower prey availability, snakes moved more linearly, gained less weight, and had lower reproductive output relative to RCAV. In addition, RCAV received approximately 4 centimeters more precipitation from May to September than the rest of the sites. There was no difference in estimated available foraging times between study sites or disturbance categories and no evidence for local adaptation of growth rates although due to low sample sizes there was relatively low power (0.30) for detecting a difference.
Results from these studies suggest that natural and human caused patterns on the landscape influence prey availability and subsequently that rattlesnake ecology is influenced by prey availability. Specifically, relatively high precipitation likely provides high prey availability at RCAV relative to CRAB. Disturbance lowers prey availability levels at both sites. Likely in response to low prey availability, snakes are making more linear movements as they search for prey and are gaining less weight. Less weight gain is likely resulting in lower body condition and growth. Snakes in areas where they gain less weight also have lower reproductive output. These findings have applied implications for the conservation of sagebrush steppe, predators, and rattlesnakes. For example, wildlife management programs interested in maintaining rattlesnake populations need to consider broad patterns of landscape disturbance and their resulting impacts on prey availability.
Amy D. Forman, Environmental Surveillance, Education, and Research Program,
S.M. Stoller Corporation, Idaho Falls, ID
Brandy C. Janzen, Graduate Student, Department of Biological Sciences, Idaho
State University, Pocatello, ID
Matthew J. Germino, Associate Professor, Department of Biological Sciences,
Idaho State University, Pocatello, ID
U.S. Department of Energy Idaho Operations Office
Shallow land burial is the most common method for disposing of industrial, municipal, and low-level radioactive waste, but in recent decades it has become apparent that conventional landfill practices are often inadequate to prevent movement of hazardous materials into ground water or biota (Suter et al. 1993, Daniel and Gross 1995, Bowerman and Redente 1998). Most waste repository problems result from hydrologic processes. When wastes are not adequately isolated, water received as precipitation can move through the landfill cover and into the wastes (Nyhan et al. 1990, Nativ 1991). Presence of water may cause plant roots to grow into the waste zone and transport toxic materials to aboveground foliage (Arthur 1982, Hakonson et al. 1992, Bowerman and Redente 1998). Likewise, percolation of water through the waste zone may transport contaminants into ground water (Fisher 1986, Bengtsson et al. 1994).
In semiarid regions, where potential evapotranspiration greatly exceeds precipitation, it is theoretically possible to preclude water from reaching interred wastes by (1) providing a sufficient cap of soil to store precipitation that falls while plants are dormant and (2) establishing sufficient plant cover to deplete soil moisture during the growing season, thereby emptying the water storage reservoir of the soil.
The Protective Cap/Biobarrier Experiment (PCBE) was established in 1993 at the Experimental Field Station, INL to test the efficacy of four protective landfill cap designs. The ultimate goal of the PCBE is to design a low maintenance, cost effective cap that uses local and readily available materials and natural ecosystem processes to isolate interred wastes from water received as precipitation. Four evapotranspiration (ET) cap designs, planted in two vegetation types, under three precipitation regimes have been monitored for soil moisture dynamics, changes in vegetative cover, and plant rooting depth in this replicated field experiment.
From the time it was constructed, the PCBE has had four primary objectives which include; (1) comparing the hydrologic performance of four ET cap designs, (2) examining the effects of biobarriers on water movement throughout the soil profile of ET caps, (3) assessing the performance of alternative ET cap designs under current and future climatic scenarios, and (4) evaluating the performance of ET caps planted with a diverse mix of native species to those planted with a monoculture of crested wheatgrass.
Specific tasks for the PCBE in 2006 included maintenance of the study plots, continuation of the irrigation treatments, and collection of soil moisture and plant cover data. An update to the 2003 PCBE summary report (Anderson and Forman 2003) was also scheduled to be drafted in 2006. Data were analyzed for the updated summary report according to the four major objectives listed above, focusing on long-term cap performance. Four additional objectives, which address emerging landfill-capping issues, were also considered in the summary report. The additional objectives include; (1) comparing plant cover and soil moisture dynamics from the 1994-2000 study period with the relatively more droughty 2002-2006 study period, (2) assessing the stability of total vegetation cover both spatially and temporally, (3) understanding the invasibility of the native and crested wheatgrass plant communities planted on the PCBE, and (4) quantifying the relationship between vegetation cover and evapotranspiration.
Three supplemental irrigation treatments were completed on the PCBE in 2006. The fall/spring supplemental irrigation treatment initiated in late September 2005 could not be completed due to a failure of the deep well. Therefore, the deep well was repaired and the balance of the fall/spring irrigation treatment was applied in April of 2006. A summer irrigation treatment was also performed, as scheduled, in 2006. Fifty millimeters of water was applied to the summer irrigated plots once every other week from the end of June through the beginning of August for a total of 200 mm. Finally, the fall/spring 2006 irrigation treatment was completed in mid-October. Soil moisture measurements were collected once every two weeks from beginning of April through mid-October. Vegetation cover data were collected throughout the month of July and into August.
Soil moisture and vegetation cover data from 1994-2006 were analyzed according to the objectives described above. A draft of the updated summary report was completed at the end of 2006 and was published in February 2007. A copy of the report, entitled “PCBE Revisited: Long-Term Performance of Alternative Evapotranspiration Caps for Protecting Shallowly Buried Wastes under Variable Precipitation” (Janzen et al. 2007) is available at www.stoller-eser.com.
During the 2002-2006 study period, an alternative ET cap design with a gravel/cobble biobarrier placed at a depth of one meter below the soil surface prevented potential water breakthrough to the simulated waste zone better than the other three designs tested. The capillary break created by the change in substrate texture at the interface of soil and gravel at the top of the biobarrier appears to enhance cap function by forcing the soil above the biobarrier to reach field capacity before water will percolate below the biobarrier, limiting unsaturated flow and preferential flow pathways. These results were similar to those reported for the 1994-2000 study period. In contrast to results reported from the earlier study period, the performance of an alternative design consisting of a two meter soil monolith began declining over the past four years. Two additional cap designs, one based on Resource Conservation and Recovery Act (RCRA) guidelines and the other an alternative ET design with a biobarrier placed at 0.5 m below the soil surface, performed during the second study period much as they had in the first. Water often collected on the flexible membrane liner of the RCRA cap and often percolated below the biobarrier on the design with the shallowly placed biobarrier. In both cases, this percolation didn’t necessarily lead to potential breakthrough at the bottom of a cap, but it does indicate that more soil is needed to prevent water from reaching these physical barriers.
The caps planted with a diverse mix of native vegetation continued to perform better than those planted with a crested wheatgrass monoculture. In fact, crested wheatgrass does not appear to provide adequate transpiration to maintain long-term ET cap function. Poor performance of caps planted with crested wheatgrass may be related to relatively low vegetative cover overall and relatively high variation in vegetation cover spatially and temporally. Caps planted with crested wheatgrass tended to have lower average plant cover that caps planted with native vegetation. The stability of the crested wheatgrass plant community tended to be lower than that of the native plant community as evidenced by the relatively high variability in vegetative cover among caps planted with crested wheatgrass. Additionally, the crested wheatgrass caps had a high incidence of encroachment of species that were not originally planted when compared to encroachment of crested wheatgrass into the native vegetation caps.
When performance of the four cap designs was compared in response to ambient precipitation and two climate change scenarios, all of the cap designs experienced at least one potential breakthrough event under an augmented fall/spring precipitation scenario during the 2002-2006 study period (Figure 9-10). This result was not observed during the 1994-2000 study period and indicates that none of the cap designs would function properly under extreme climate change in which the INL received twice current ambient precipitation during the winter months. As with the first study period, potential breakthroughs were rare under ambient precipitation and augmented summer irrigation. The potential breakthrough events that did occur under those precipitation scenarios occurred only on the caps planted with crested wheatgrass (Figure 9-10). Thus, when planted with native vegetation, all four cap designs precluded water from percolating through the bottom of the cap under current climatic conditions.
Over the next two growing seasons we will monitor vegetation cover and soil moisture as we continue to assess long-term alternative ET cap performance. Weak correlations between vegetation cover and evapotranspiration in analyses conducted for the updated summary report indicate that simple paradigms of soil-plant water relationships may not be adequate to explain the performance of ET caps. Therefore, we will also collect some finer time-scale vegetation cover measurements and direct transpiration measurements throughout the growing season in 2006. These additional measurements will be used to better characterize and quantify the soil-plant water relationship on the PCBE, which will be useful for modeling long-term cap performance, as well as improving cap performance through directed revegetation design.
Christopher L. Jenkins, Conservation Scientist, North America Program,
Wildlife Conservation Society, Idaho Falls, ID
Craig Groves, Conservation Scientist, North America Program, Wildlife
Conservation Society, Bozeman, MT
United States Department of Energy, Idaho Operations Office
The sagebrush steppe of western North America is one of the most endangered ecosystems in the world. Sagebrush steppe is threatened by soil disturbance (especially associated with overgrazing) that promotes invasion by exotic annual vegetation (such as cheatgrass, Bromus tectorum) which in turn alters natural fire regimes. These types of landscape changes are having significant effects on sagebrush steppe wildlife. Despite the widespread nature of the threats to sagebrush steppe, the INL has experienced only limited disturbance and is likely the most intact example of sagebrush steppe remaining.
Without an adequate management plan in place the biodiversity of sagebrush habitats on the INL are at a greater risk of being degraded. Localized threats to biodiversity on the INL include livestock grazing in peripheral areas, invasion of cheatgrass (Bromus tectorum) and crested wheatgrass (Agropyron cristatum), fire, raven depredation, and road and facility development. In addition, complex interactions can exist between threats.
Developing a conservation management plan for the INL is important because it will help preserve one of the best remaining sagebrush steppe ecosystems in the world. A conservation management plan is also important to DOE because it will facilitate land use planning on the INL. For example, with a conservation management plan in place and an understanding of the distribution of important biological resources DOE will save time and money when planning projects such a new construction.
The overall goal of the project is to conserve sagebrush steppe ecosystems while facilitating land use planning on the INL. Specific objectives include:
Some of the objectives above will be focused on the entire INL (Pygmy Rabbit Studies, Sage Grouse Studies, and Vegetation Mapping) while the Biodiversity Inventory will be focused in two smaller areas in the south central part of the INL designated the Development Corridor and Development Zone (Figure 9-11). Thus, conservation priorities, the interactive planning tool, and the Conservation Management Plan (CMP) will only completely cover all important biological resources within these two areas.
Pygmy Rabbit Surveys
In 2006 we conducted, developed and applied a novel ground surveying
technique for pygmy rabbits. Specifically, we developed an approach where
observers on snowshoes survey plots along a series of belt transects. Within
each transect observers are keying in on rabbit microhabitat characteristics
(e.g., relatively tall sagebrush) and searching for signs of pygmy rabbit
occupancy such as tracks, burrows, or pellets. Detection probabilities varied
based on the presence of snow and other factors but detection probabilities for
the technique were consistently of 0.70. Using this technique we identified
pygmy rabbit presence in 52 percent of the plots surveyed and we located a total
of 130 burrows systems.
Sage Grouse Surveys
In 2006 we conducted aerial and ground surveys for sage grouse
leks. We found a total of four new leks during these surveys.
Biodiversity Inventory
As part of the biodiversity inventory we selected a suite of indicator taxa
including vegetation, reptiles, passerine birds, raptors, bats, small mammals,
mammalian mesocarnivores, and ungulates. Accomplishments in 2006 by taxa are as
follows:
In 2007 we plan to continue surveys for all species mentioned above and begin surveys for mammalian carnivores and raptors. In addition, we will be beginning radio telemetry projects on sage grouse and pygmy rabbits, a study on raven depredation of sage grouse nests, and a rattlesnake population genetics project.
Lawrence L. Cook, Graduate Student, Graduate Student, Department of
Biological Sciences, Idaho State University, Pocatello, ID
Richard S. Inouye, Professor, Department of Biological Sciences, Idaho State
University, Pocatello, ID
Terence P. McGonigle, Associate Professor, Department of Botany, Brandon
University, Brandon, Manitoba, Canada
The Idaho State University Department of Biological Sciences
The Idaho State University Center for Ecological Research and Education
The Inland Northwest Research Alliance
The Idaho State University Graduate Student Research and Scholarship Committee
A Bechtel Educational Outreach Program grant awarded to Richard Inouye
Sigma Xi
This research was conducted as part of a doctoral program and has been completed.
Cesium (Cs) movement in ecosystems is important due to Cs radioisotopes introduced via nuclear technologies. Stable Cs uptake by plants is comparable to Cs radioisotopes. Three lines of investigation were used to determine stable Cs movement in the sagebrush steppe ecosystem of the eastern Snake River Plain. First, 27 sites were surveyed to determine Cs concentrations in 28 soil and 330 plant samples. Titanium (Ti) was used to indicate soil contamination on plant samples. Cesium in soils correlated with quartz and cation exchange capacity. Cesium in plants correlated with Ti. Transfer factors, i.e., the concentration ratio of plant Cs to soil Cs, were on the order of 10-3.
Second, the validity of Ti to indicate soil contamination was assessed. Milling inert filter paper indicated that background Ti levels account for concentrations to 10 mg Ti•kg plant-1. Concentrations of Ti and Cs associated with seedlings grown in a dust-free environment increased significantly with moderate dusting. Washing dust-laden plants with seven washing agents revealed none as superior in removing soil from seven species and none was effective in removing all soil from any one species. Energy dispersive spectrometry showed plant surface elemental signatures consistent with soil coatings.
Third, four grasses were evaluated as phytoremediation candidates via greenhouse experiments. The species were Agropyron spicata (bluebunch wheatgrass), A. cristatum (crested wheatgrass), Leymus cinerus (Great Basin wildrye, and Bromus tectorum (cheatgrass). Plant Cs concentrations were higher in Cs-spiked soil. Total Cs per seedling was greatest in the high Cs, high fertility, and high moisture soil treatment combination.
These studies indicated: (1) the uptake of Cs by regional plants is low and much of the Cs is in soil adhering to plant surfaces, (2) Ti is a reliable indicator of soil contamination for plant samples slated for trace element analysis and should be used when assessing trace element composition of field samples, and (3) Great Basin wildrye, bluebunch wheatgrass, crested wheatgrass, and cheatgrass are viable phytoremediation agents when used in a strategy combining soil fertilization and irrigation and possibly stable Cs addition. Preference should be given to the native bluebunch wheatgrass and Great Basin wildrye because they do not negatively impact regional biodiversity.
Lora Perkins, Ph. D. student, Department of Natural Resources and
Environmental Science, University of Nevada Reno, Reno NV
Robert S. Nowak, Professor, Department of Natural Resources and Environmental
Science, University of Nevada Reno, Reno NV
Kimberly G. Allcock, Postdoctoral Associate, Department of Natural Resources and
Environmental Science, University of Nevada Reno, Reno NV
U.S. Department of Energy Idaho Operations Office
Nevada Arid Rangeland Initiative and the Nevada Agricultural Experiment Station
Predicting plant community susceptibility to invasion by introduced species and determining mechanisms of resistance are fundamental concerns of ecology and ecosystem management. In the Great Basin, the invasive introduced annual cheatgrass (Bromus tectorum) currently dominates 3 million acres, with another 14 million acres heavily infested and 60 million acres considered at risk for potential domination (Pellant and Hall 1994). However, the eastern portion of the Snake River Plain, including the INL, has largely escaped the cheatgrass dominance found in the western portions of the Snake River Plain and in northern Nevada.
Anderson and Inouye (2001) concluded that maintenance of cover of native species may make the vegetation of the INL resistant to invasion. However, the eastern Snake River Plain also differs climatically from most cheatgrass-invaded areas: winter temperatures are colder and there is more late spring precipitation. The relatively minor extent of cheatgrass invasion at the INL in comparison with surrounding areas provides a unique opportunity to identify environmental conditions, community characteristics, or management practices conferring ecosystem resistance to invasion.
The goal of this project is to use a combination of field surveys and mechanistic hypothesis-driven greenhouse experiments to determine the influences of environment, plant community, and land management on invasion success.
Comparative surveys - We will conduct comparative surveys along a latitudinal climatic gradient from north central Nevada, where cheatgrass dominates much of the landscape, to the INL. We will establish sampling plots at several hundred locations in four areas along this ‘mega-transect’ taking care to adequately sample sites with different types of disturbance and management histories as well as different vegetation composition and temperature and precipitation regimes. We will sample intensively at the INL; at sites near INL (and therefore climatically similar) but with different land use and ownership; at sites in far southern Idaho and northern Nevada (Owyhee Plateau) with a range of disturbance and community composition; and in north central Nevada near a set of permanent experimental plots that were established to assess restoration success of cheatgrass-dominated rangeland (Allcock et al. 2006). We will use information ranging in scale from microscopic (nutrients and microbes) to landscape (climate and land use patterns) to parameterize a structural equation model (SEM) (Grace 2006) and specifically test hypotheses about how site characteristics affect invasion success of cheatgrass.
SEM is a powerful statistical way to infer causality: specifically we will use it to determine why cheatgrass is more abundant in certain locations and less abundant in others. An additional benefit of SEM is that we can include variables based on ‘expert opinion’ rather than relying on strictly empirical data. This means we can include a wealth of invaluable information that would not be otherwise useable in a quantitative model. We will be collecting observational data from the field and combining it with site specific variables.
Controlled greenhouse studies – We will use controlled-environment experiments that involve individual species and constructed communities to establish a mechanistic understanding of competition between cheatgrass and native species. We will investigate competitive relationships, effects of diversity, density, and disturbance, and response to variation in water regime (timing and pulse size). Preliminary single-species trials indicate that cheatgrass and perennial species differ in their abilities to respond to water pulses depending on size and frequency of watering events, and that moisture at the right time in the life cycle of cheatgrass could promote high competitive ability and possibly invasion (K. Allcock, unpublished data). A mesocosm experiment is currently underway to test the interactions of precipitation timing and community composition in determining invasion success.
Comparative surveys – In September 2006, we visited the INL and traveled the length of our proposed ‘mega-transect’ to identify potential sampling locations. We have obtained and are processing fire history, soil maps, vegetation classification data and digital elevation models for the sampling areas we identified. We will convert the information to digital GIS layers and use the GIS to help with the selection of exact data collection points. The GIS will also provide information that will be used in the final SEM model.
Controlled greenhouse studies – In September and October of 2006 we began establishing an experiment to test the effects of community composition, precipitation amount, and precipitation timing on establishment and success of cheatgrass. We collected individuals of six perennial grass species from a field location near Reno, NV. We used these to create a series of two-species ‘communities’ in 50-gallon barrels in a greenhouse on the University of Nevada campus. These communities are composed of species that are active earlier in the growing season (Poa secunda, Acnatherum hymenoides, and Elymus elemoides), later in the growing season (Hesperostipa comata, A. thurberiana, and Pseudoroegneria spicata), or a combination (one early species and one late species). One quarter of the barrels contain no perennial plants. Between April 2007 and June 2007 these communities will receive either a total amount of water based on the long-term average precipitation for the Reno area, or an elevated amount of precipitation (in line with climate change predictions; 50 percent more than the long term average). This total amount of water will be administered either primarily in the ‘early season’ (April-May) or in the ‘late season’ (May-June). All communities have been seeded with cheatgrass at a rate of 2000 seeds per m2. In summary, there are four community types (early, late, mixed, no perennials); two total water levels (ambient, elevated); and two precipitation timings (early, late). We have six replicates for each treatment combination, giving a total of 96 barrels. We will monitor soil moisture; cheatgrass density, biomass, seed production and photosynthetic rates; and the growth, reproduction, and photosynthetic rates of the perennial plants.
This project was still in its developmental stage in 2006, and we have not collected any field or experimental data. We have begun to compile site-related information including fire history, climate variables, soil survey data, and topographic variables into a GIS database. We will begin collecting data on our greenhouse studies in May 2007.
This project will continue through 2009. We will begin collecting field data from the comparative field plots at INL and other areas starting in late-May and June 2007. In subsequent seasons, we will continue to collect vegetation, soil and climate data from additional survey plots in order to obtain as much data as possible for parameterization of the SEM. SEMs may require a minimum of 100 data points in order for the algorithms used to identify reliable parameter values (Tanaka 1987), and we aim to sample approximately 400 individual plots among the four locations through the course of the study.
As outlined in the previous section, our mechanistic greenhouse study is just getting underway and this experiment will continue through the end of June 2007. We will use the results from this first experimental iteration to refine our understanding of how precipitation timing, precipitation amount and community composition affects cheatgrass performance. We will perform additional greenhouse studies over the next several years to test and refine further our understanding of the mechanisms of plant interaction and cheatgrass establishment in perennial grass ecosystems.
We anticipate several peer reviewed publications (e.g. the results of the SEMs and the results of the greenhouse experiments) and conference proceedings in addition to the Ph.D. dissertation to be completed by Lora Perkins in 2009.
Amy D. Forman, Plant Ecologist, Environmental Surveillance, Education and
Research Program, S.M. Stoller Corporation, Idaho Falls, ID
Roger D. Blew, Ecologist, Environmental Surveillance, Education and Research
Program, S.M. Stoller Corporation, Idaho Falls, ID
U.S. Department of Energy Idaho Operations Office
As more and more sagebrush steppe habitat in good ecological condition is lost, it becomes increasingly important to understand the ecosystem dynamics of that vegetation type, especially the biology of the dominant species, sagebrush. An understanding of the population dynamics, or demography, of sagebrush should allow land managers to make better decisions about remaining healthy sagebrush steppe vegetation. An understanding of what the historical population dynamics of a sagebrush stand may have been like will also allow land managers to begin to understand how to make improvements in sagebrush steppe communities that are in somewhat degraded conditions.
At the INL, the DOE is responsible for the stewardship of 2300 km2 of relatively pristine sagebrush steppe habitat. This land comprises one of the largest remnants of this type of ecosystem that has been largely exempt from anthropogenic disturbance. Some of the primary issues DOE must address as a land manager include: fire risk and fuel management, post-fire vegetation recovery, rangeland health, wildlife habitat management (including habitat critical to the survival of threatened, endangered, and sensitive species), and land use planning. Sagebrush is an important component of managing for all of these issues. Unfortunately, the population biology of sagebrush is not well understood. In particular, very little information is available on the typical age structure of sagebrush stands, the frequency of recruitment events, the dynamics of shrub die-off, and the typical lifespan of sagebrush.
The overarching goal of this proposed study is to describe sagebrush stand age structure for a representative sample of sagebrush stands and to identify the population dynamics that influence that structure at the INL. Characterizing sagebrush stand age structure is a critical component to managing sagebrush steppe ecosystems, and understanding some of the basic biology of sagebrush can add tremendously to DOE’s ability to make knowledgeable land management and land use decisions. A simple study to establish a working knowledge of the age dynamics of sagebrush stands can yield information useful to those land management issues listed above. Many of the results from this study may also be applied to sagebrush stands with similar climatic conditions and disturbance regimes range-wide, allowing range managers throughout the West to use these data.
The working knowledge of the dynamics of stand age structure gained from this study will allow managers to better address all of the land management issues mentioned above. The specific objectives for this project are:
By addressing these goals, the proposed study will facilitate a comprehensive understanding of sagebrush population biology on the INL and on climatically similar rangelands. That improved understanding of sagebrush ecology will include the normal age structure of sagebrush stands, the typical range of variation of sagebrush stand age structure, how age structure of a sagebrush stand relates to stand condition, the dynamics of shrub die-off, the typical lifespan of sagebrush, the frequency of recruitment events, and the relationship between recruitment and disturbance.
The expected deliverables for the project will support the development of the Conservation Management Plan and include (1) specific habitat management recommendations for sagebrush at the INL and, (2) guidance for assessing the status of sagebrush habitat health on the INL.
During 2006, 14 stands of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) were sampled. The vegetation data collected as a component of this study included; shrub cover, sagebrush density, and individual shrub rank data for use in developing criteria for measuring stand condition. At each stand, cross section samples of sagebrush were also collected. The cross sections were labeled and archived in preparation for sanding and ring counts.
Because data collection was initiated in 2006 and no data analyses have yet been completed, no results are reported here.
Funding for this project has been discontinued.
Amy D. Forman, Plant Ecologist, Environmental Surveillance, Education and
Research Program, S.M. Stoller Corporation, Idaho Falls, ID
Roger D. Blew, Ecologist, Environmental Surveillance, Education and Research
Program, S.M. Stoller Corporation, Idaho Falls, ID
Jackie R. Hafla, Natural Resources Scientist, Environmental Surveillance,
Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID
U.S. Department of Energy Idaho Operations Office
In 1950 at the request of the Division of Biology and Medicine of the Atomic Energy Commission requested a background survey for naturally occurring radioactive materials in the vicinity of what is now known at the INL. One of the legacies of that background survey in 1950 remains today in the form of the Long-Term Vegetation (LTV) plots. The LTV plots originally consisted of 110 plots on and near the INL. Over the years some of the plots have been lost due to agricultural and other development activities and 92 plots remain. These plots were surveyed in 1950, 1957, 1965, 1975, 1985, 1995 and 2001. A subset of 35 or 36 plots were also surveyed in 1978, 1983, and 1990.
The plots originally consisted of two transects 50 ft (15.24 m) in length. Vegetative cover of shrub crown and grass basal area was measured using line intercept and density was measured in quadrats placed at intervals of 5 ft (1.52 m) along the two transects. In 1985, a third transect 65.6 ft (20 m) in length was added to each plot to support measurement of cover using point interception. Also, a photographic record of each plot has been made during each survey beginning in 1957.
Although the original intent of the LTV plots was to provide information on presence of naturally occurring radioactive materials in the environment, the data from these plots have also been used to assess the potential impact of nuclear energy research and development and other activities on ecological resources native to the INL. The LTV plots have provided important background information for assessing potential impact to ecological resources in numerous Environmental Assessments and Environmental Impact Statements at the INL.
Also, the LTV data have become an invaluable resource for research on the structure and function of native sagebrush steppe vegetation communities. The INL LTV plots represent one of the most intensive (in terms of the amount and kinds of data available for each plot) and one of the most extensive (in terms of its geographical and temporal extents) datasets for the sagebrush steppe ecosystem type. The significance of this dataset to the broader scientific and natural resource management communities is further amplified when considering that it represents the largest remnant of good condition sagebrush steppe. This significance is illustrated by the paper by Anderson and Inouye (2001) that provided a summary of this dataset through 1995. In the first five years following publication, this paper was cited more than 40 times in the scientific literature.
There are three primary goals for current activities associated with the LTV project. They include surveying plots in 2006, analyzing data and preparing reports and manuscripts in 2007, and archive all data collected since 1959 and incorporating that archive into the CMP Ecological Data Management System. Research objectives for this effort include investigating methods for studying the population ecology of native bunchgrasses, the role of annual forbs in the ecology of sagebrush steppe communities and environmental controls on diversity of forbs.
Data collection began in June 2006 and continued through July. We surveyed all of the 92 remaining LTV plots. Field crews were trained in late May and early June on survey methods and plant identification. We conducted Quality Assurance/Quality Control audits on all data collected as they were brought in from the field. There was a lag of no more than one week between data collection and these audits.
Once the field data collection was completed, we began data analysis. Because of the short amount of time between the completion of data collection and the end of the fiscal year, data analysis in 2006 was limited to transforming the data so that it is in a format consistent with the needs of the statistical analysis.
Because only limited data manipulation was completed in 2006, no results are available to be reported here.
In 2007 we plan to complete the data analysis and report preparation. We also plan to begin work on at least two manuscripts based on the results of the study. In 2007 and continuing into 2008, we will begin the process of archiving the LTV data into the CMP data management system. This will include converting all of the photographic negatives into digital format.
Allcock, K, R. Nowak, R. Blank, T. Jones, T. Monaco, J. Chambers, R. Tausch, P. Doescher, J. Tanaka, D. Ogle, L. St. John, M. Pellant, D. Pyke, E. Schupp and C. Call (2006) Integrating weed management and restoration on western rangelands. Ecological Restoration 24:199-200.
Anderson, J.E., and A.D. Forman. 2003. Evapotranspiration Caps for the Idaho National Engineering and Environmental Laboratory: A Summary of Research and Recommendations. Environmental Surveillance, Education, and Research report, Stoller Corporation and Idaho State University, STOLLER-ESER-56.
Anderson, J., and R. Inouye. 2001. Landscape scale changes in species abundance and biodiversity of a sagebrush steppe over 45 years. Ecological Monographs 71:531-556.
Arthur, W.J. 1982. Radionuclide concentrations in vegetation at a solid radioactive waste disposal area in southeastern Idaho. Journal of Environmental Quality 11:394-399.
Bengtsson, L., D. Bendz, W. Hogland, H. Rosqvist, and M. Akesson. 1994. Water balance for landfills of different age. Journal of Hydrology 158:203-217.
Bowerman, A.G., and E.F. Redente. 1998. Biointrusion of protective barriers at hazardous waste sites. Journal of Environmental Quality 27:625-632.
Clark, W.H., and P.E. Blom. 2007. Annotated checklist of the ants of the Idaho National Laboratory (Hymenoptera: Formicidae). Sociobiology 49(2):1-117.
Daniel, D.E., and B.A. Gross. 1995. Caps. National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia.
Fisher, J.N. 1986. Hydrogeologic factors in the selection of shallow land burial for the disposal of low-level radioactive waste.
Grace, J.B. 2006. Structural Equation Modeling and Natural Systems. Cambridge University Press, NY.
Hakonson, T.E., L.J. Lane, and E. P. Springer. 1992. Biotic and abiotic processes. Pages 101-146 in C.C. Reith and B.M. Thomson, editors. Deserts as dumps? The disposal of hazardous materials in arid ecosystems. University of New Mexico Press, Albuquerque, New Mexico.
Janzen, B.C., M.J. Germino, J.E. Anderson, and A.D. Forman. 2007. PCBE revisited: long-term performance of alternative evapotranspiration caps for protecting shallowly buried wastes under variable precipitation. Environmental Surveillance, Education, and Research Program report, Idaho State University and Stoller Corporation, STOLLER-ESER-101.
Nativ, R. 1991. Radioactive Waste Isolation in Arid Zones. Journal of Arid Environments 20:129-140.
Nyhan, J. W., T. E. Hakonson, and B. J. Drennon. 1990. A water balance study of two landfill cover designs for semiarid regions. Journal of Environmental Quality 19:281-288.
Pellant, M. and C. Hall. 1994. Distribution of two exotic grasses on intermountain rangelands: status in 1992. p. 109-112 In: S.B. Monsen and S. G. Kitchen (compilers). Proceedings—ecology and management of annual rangelands. General Technical Report INT-GTR-313, Ogden, UT, USDA Forest Service, Intermountain Research Station.
Suter, G.W.I.I., R.J. Luxmoore, and E. D. Smith. 1993. Compacted soil barriers at abandoned landfill sites are likely to fail in the long term. Journal of Environmental Quality 22:217-226.
Tanaka, J.S. 1987. How big is big enough? Sample size and goodness-of-fit in structural equation models with latent variables. Child Development 58: 134-146.