The Idaho National Engineering and Environmental Laboratory (INEEL) was designated as a National Environmental Research Park (NERP) in 1975. The NERP program was established in the 1970s in response to recommendations from citizens, scientists, and members of Congress to set aside land for ecosystem preservation and study. In many cases, these protected lands became the last remaining refuges of what were once extensive natural ecosystems. The NERPs provide rich environments for training researchers and introducing the public to 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.

Ecological research at the INEEL began in 1950 with the establishment of the long-term vegetation transect. This is perhaps DOE's oldest ecological data set and one of the oldest vegetation data sets in the West. Ecological research on the NERPs is leading to planning better land use, identifying sensitive areas on DOE sites so that restoration and other activities are compatible with ecosystem protection and management, and increasing contributions to ecological science in general.

The following ecological research activities took place at the Idaho NERP during 2002:

8. ECOLOGICAL RESEARCH AT THE IDAHO NATIONAL ENVIRONMENTAL RESEARCH PARK

The INEEL was designated as a NERP in 1975. The NERP program was established in the 1970s 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 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

Develop methods for assessing and documenting the environmental consequences of human actions related to energy development.

Develop methods for predicting the environmental consequences of ongoing and proposed energy development.

Explore methods for eliminating or minimizing predicted adverse effects from various energy development activities on the environment.

Train people in ecological and environmental sciences.

Use the NERPs for educating the public on environmental and ecological issues.

The NERPs provide rich environments for training researchers and introducing the public to 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 INEEL began in 1950 with the establishment of the long-term vegetation transect. This is perhaps DOE's oldest ecological data set and one of the oldest vegetation data sets in the West. Other long-term studies conducted on the Idaho NERP include the reptile monitoring study initiated in 1989 and 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 planning better land-use, identifying sensitive areas on DOE sites so that restoration and other activities are compatible with ecosystem protection and management, and increasing contributions to ecological science in general.

The Idaho NERP provides a coordinating structure for ecological research and information exchange at the INEEL. The Idaho NERP facilitates ecological research on the INEEL by attracting new researchers, providing background data to support new research project development, and providing logistical support for assisting researcher access to the INEEL. 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 INEEL 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 2002.

8.1 Monitoring Amphibian and Reptile Populations on the INEEL: Indicators of Environmental Health and Change

Investigators and Affiliations

Charles R. Peterson, Professor, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID

Christopher L. Jenkins, Graduate Student, Herpetology Laboratory, Department of Biological Sciences, Idaho State University, Pocatello, ID

Funding Sources

U.S. Department of Energy Idaho Operations Office

Background

Many amphibian and reptile species have characteristics that make them sensitive environmental indicators. The main research goal is to provide indicators of environmental health and change by monitoring the distribution and population trends of amphibians and reptiles on the INEEL.

Information from this project is important to the DOE for several reasons: (1) as an indicator of environmental health and change, (2) for management of specific populations of sensitive species, (3) for meeting NEPA requirements regarding the siting of future developments, (4) for avoiding potentially dangerous snake-human interactions, and (5) for providing a basis for future research into the ecological importance of these species. Additionally, this project provides venomous snake safety training to INEEL employees and summer assistants. This training provides key information on how to avoid and treat bites from venomous snakes. It also helps workers place the relatively low risk of snakebite in perspective and fosters an appreciation of the ecological role of snakes on the INEEL. Finally, this project assists in the training and support of undergraduate and graduate students in environmental research.

Objectives

The overall goal of this project is to determine amphibian and reptile distribution on the INEEL and monitor populations in select areas. Specific objectives for 2002 included the following:

Continue monitoring snake and lizard populations;
Provide herpetological expertise as needed; and
Provide snake safety workshops.

Accomplishments through 2002

Specific accomplishments for 2002 include the following:

Snake monitoring efforts continued at three den sites, allowing more accurate estimates of specific populations of reptiles on the INEEL to be made. These estimates will allow examination of population trends over time. Population size and survival estimates for snake communities on the INEEL are currently being evaluated.
The INEEL herpetological database was updated using the observations gained from this research (Figure 8-1).
Herpetological expertise was provided to numerous groups on the INEEL in 2002, including snake safety training sessions and field safety consultations.
Three new communal snake dens were discovered in the southeastern portion of the INEEL.

Figure 8-1. Updated herpetological database for the INEEL.
Reptile and amphibian observations are a combination of museum records,
survey records, and contributed observations.

Results

Important results this year included confirming the continued presence of leopard lizards (Crotaphytus wislizenii) through observation at Circular Butte, finding new snake hibernacula, beginning radiotelemetry studies, and providing specific herpetological expertise to several groups on the INEEL.

The number of marked snakes on the INEEL increased in 2002 to 3086, including all snakes PIT-tagged since 1994 and marking data collected at Cinder Butte from 1989-1994.
Two observations of a leopard lizard were made at Circular Butte in 2002. Many western skinks (Eumeces skiltonianus) and sagebrush lizards (Sceloporus graciosus) were sighted across the entire INEEL, and short-horned lizards (Phrynosoma douglassii) were observed across the southeastern end of the Site.
Breeding activity by spadefoot toads was not observed on the INEEL in 2002.
Radiotelemetry work began in the southeastern portion of the INEEL as part of Mr. Jenkins’ Ph.D. research, to look at the effects of landscape characteristics on dispersal and mating systems.
Three additional communal dens sites were found in the southeastern portion of the INEEL. Snake communities at Twin Buttes Crater were comprised of gopher snakes (Pituophis catenifer), western rattlesnakes (Crotalus viridis), and terrestrial garter snakes (Thamnophis gans); at North Tower Cave they were comprised of gopher snakes and western rattlesnakes; and at Amazon Butte they were comprised of western rattlesnakes and terrestrial garter snakes.
Herpetological expertise was provided in the form of seven snake safety training sessions, disseminating herpetological data for the site, and conducting field safety consultations. The snake safety-sessions have all generated positive feedback from the employees, and many also yield invitations for additional presentations, both on the INEEL and in local communities.
Data on road-killed reptiles are being used to develop a research project for an Idaho State University graduate student on the effects of roads on snake populations.

**8.2 Behavior, Dispersal, and Survival of Captive-Raised Idaho Pygmy Rabbits (Brachylagus idahoensis) Released onto the INEEL in Idaho**

Investigators and Affiliations

Rodney D. Sayler, Associate Professor, Department of Natural Resource Sciences, Washington State University, Pullman, WA

Lisa A. Shipley, Associate Professor, Department of Natural Resource Sciences, Washington State University, Pullman, WA

Robert Westra, Graduate Student, Department of Natural Resource Sciences, Washington

State University, Pullman, WA

Funding Sources

Washington Department of Fish and Wildlife

Background

The pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit in North America, a sagebrush foraging specialist, and one of only two North American rabbits to dig its own burrow. The Columbia Basin pygmy rabbit (Brachylagus idahoensis) is a distinct population of native rabbit that once occupied Douglas, Grant, Lincoln, Adams, and Benton Counties in central Washington. Pygmy rabbits occur in other areas of the West, but the Columbia Basin population is genetically unique, has been isolated from other populations for thousands of years, and occupies an unusual ecological setting. The long-isolated and genetically unique population of Columbia Basin pygmy rabbits located in Washington State has declined precipitously to dangerously low levels. Therefore, the U.S. Fish and Wildlife Service recently listed the Columbia Basin pygmy rabbits as an endangered population segment. Since little is known about successful captive rearing and methods for restoring pygmy rabbits back into vacant natural habitats, reintroduction techniques are being tested in southeastern Idaho to develop protocols for the eventual restoration of endangered pygmy rabbits in Washington State. Idaho pygmy rabbits are propagated in captivity at Washington State University and elsewhere and released into the wild in southeastern Idaho to determine whether selected captive rearing and release methods influence the behavior, dispersal, and survival of pygmy rabbits reintroduced into suitable sagebrush habitat.

Objectives

Specific objectives of this research include:

Develop techniques to enhance the survival of captive-bred Idaho pygmy rabbits released into natural habitats for the purpose of establishing new local populations of pygmy rabbits;

Test the effects of captive-rearing and release methods on the resulting behavior, dispersal, and survival of reintroduced pygmy rabbits; and

Develop recommended protocols for restoring Columbia Basin pygmy rabbits in areas of vacant, suitable sagebrush habitat and model the numbers of captive-bred animals and survival rates needed to establish new local breeding populations.

Results

All released rabbits readily adapted to the small, temporary holding cages surrounding their burrow openings and continued normal feeding on provided foods (i.e., sagebrush tips, spinach, lettuce, and pellet food). All containment pens were removed from the burrows by the fourth day, allowing free movement and dispersal of the animals.

Eleven of the 20 released animals made dispersal movements away from their release burrow ranging from about 36 m (120 ft) to 1.1 km (0.7 mi). All but one of the dispersing animals selected other appropriate habitat consisting of relatively tall, dense big sagebrush with relatively good grass and forb availability. Released animals appeared to adapt to natural local forage quickly and also appeared to use a high proportion of grass and forbs until colder weather began in October, which prompted greater use of sagebrush.

Nondispersing animals continued to use the artificial burrows provided on the release site, sometimes using their own and two or more burrows of adjacent released animals. Despite dispersal by some animals, the two release groups created a local cluster or loose colony of interacting individuals going into Fall 2002.

By November 2002, only five of the original 20 released rabbits were still alive. However, mortality appeared to be higher during late summer while raptors were observed on the study area and declined later in the fall after the fall raptor migration had ended. All known mortalities were attributed to either raptors or coyotes. Over winter mortality was low and four rabbits survived until the spring breeding season in April 2003. Thus, despite default expectations of high mortality in captive-reared and released pygmy rabbits, surprisingly, the first release of pygmy rabbits ever attempted was successful in carrying surviving animals through to the next breeding season.

Plans for Continuation

Idaho pygmy rabbits are currently being bred at a propagation facility at Washington State University to provide 30+ animals for conducting a second test of release methods for pygmy rabbits in summer and fall 2003. A second release site near the original release site has been selected and will be prepared with another series of 12-15 artificial burrows so that two separate release populations can be studied on the same general INEEL study area.

During the summer of 2003, the effects of reduced human contact on initial behavior and survival of released pygmy rabbits will be evaluated. In addition, a cohort of about six adult rabbits will be compared with the 30+ juvenile rabbits intended for release.

Based upon the first field season of observations in 2002, several aspects of the release techniques are being improved for summer 2003. In addition, year 2002 data on behavior, dispersal, and survival are being analyzed and a short publication based on these initial, but important results, is being prepared.

This study on the INEEL is a major component of the recovery program for the endangered Columbia Basin pygmy rabbit, but will also provide valuable information in the event that local reintroductions are ever warranted for Idaho pygmy rabbits. A more detailed progress report is available from the Investigators upon request.

8.3 Alternative Container Design for Large Acreage Revegetation

Investigators and Affiliations

Tim Meikle, Director of Research and Development, Bitterroot Restoration, Inc., Corvallis, MT

Funding Sources

U.S. Department of Agriculture Small Business Initiative Research Grant

Background

Revegetation of arid lands disturbed by fire, or by cropping, mining, and other activities, represent a continuous and substantial expenditure by the responsible entities. Federal legislation such as the Surface Mining Control and Reclamation Act, the Conservation Reserve Program, and Comprehensive Environmental Response, Compensation, and Liability Act require the planting of native seed/seedlings and the expenditure of millions of dollars annually on sites that are highly disturbed or contaminated from activities such as mining, agriculture, industrial activities, and forest fires.

With regards to arid land shrubs, mechanical seeding and transplanting of nursery-grown plant materials compete directly for revegetation dollars but are not equal in their efficacy. Mechanical seeding is an inexpensive, but highly ineffective means of restoring arid land shrubs to disturbed sites. Mechanical seeding of arid land shrubs has proven largely ineffective for several reasons, including low seed efficiency, low seed availability, inability to effectively produce large quantities of seed from appropriate genotypes, and the increased hazard of noxious weeds introduction either naturally or from wildland seed collections. Transplanting of nursery propagated arid land shrubs, in contrast, negates many of these concerns and is highly successful but can be prohibitively expensive. If the cost of effective arid land planting stock can be substantially reduced, however, transplanting will likely become the revegetation method of choice on millions of acres of lands damaged by fire, mining, agricultural activities, and other disturbances.

The primary cause for this failure to produce cost-effective arid land planting stock is the lack of a container system designed specifically for arid land plant species. Current container systems have been designed for horticultural and forestry applications. In general, plant species grown for these applications are ecologically, morphologically, and physiologically different than arid land plant species grown for restoration projects. When these factors are taken into account, it is possible to design a short duration, high-density plant container system that will minimize nursery inputs without sacrificing infield survival. The benefit to be realized by clients is an inexpensive, highly adaptable source of arid lands planting stock that provides successful field establishment. A substantial potential market exists for a container plant system that produces low cost seedlings for arid lands restoration projects.

Bitterroot Restoration, Inc. in collaboration with U.S. Department of Agriculture, Agricultural Research Services received a Phase I U.S. Department of Agriculture Small Business Initiative Research grant to develop a low cost alternative container design for use in large-scale transplanting projects in arid lands. This project is being conducted at a number of locations across the western United States including the Idaho National Environmental Research Park at the INEEL.

Results

Plant survival varied widely between sites and was highly dependent upon site moisture conditions. In general, the Bingham Canyon, Utah site was a dramatic success, while all other sites were judged as failures. Bingham Canyon received the highest precipitation amount (60 cm [19.7 in]) while La Plata Mine received the lowest precipitation (6.4 cm [2.5 in]). The Bingham Canyon Mine site experienced the most favorable moisture conditions resulting in excellent survival of Booth Tube containers (76 percent). At this site, the Booth Tube was equal to the Zipset for highest survival and exceeded all other containers. The high elevation of Bingham Canyon resulted in cooler temperatures, lower evapotranspiration, and higher rainfall than other sites. Areas with poor growing season precipitation and minimal subsoil moisture reserves fared much more poorly than Bingham Canyon Mine. Booth Tubes were marginally successful (<10 percent survival) on sites receiving less than 30-cm (12-in.) of precipitation. North Antelope Coal Mine (10 percent) and INEEL (9 percent) had the next highest Booth Tube survival while all other sites experienced two percent or less Booth Tube survival. In contrast, the commercially available containers with more mature plant material experienced generally high survival on all sites with the exception of Hanford Reach National Wildlife Refuge and the Bureau of Land Management (BLM) Worland site. Both of these sites experienced less than 13-cm (5-in.) of precipitation during the October 2001 to September 2002 period.

Late frosts impacted Booth Tube seedlings at some sites. During the planting of the Caballo, North Antelope, and Worland-BLM sites, snow and freezing temperatures occurred for several days during and after planting. Black spots were noted on the dicots of Booth Tube seedlings, an indication of frost damage. In contrast, all of the commercial container material was dormant and immune to the effects of frost damage. Potential frost damage is a concern for the Booth Tube planting system. Previous research has indicated that winterfat (Ceratoides lanata), another dryland shrub, is highly tolerant of freezing temperatures during the dicot stage but damaged easily during the true leaf stage. An assumption for this study is that the same would be true of sagebrush. Further research to investigate frost tolerance of arid lands shrubs is proposed in Phase II.

Soil type may have also played a role in low survival of Booth Tube seedlings. Booth Tube containers removed from the INEEL site and the Natural Resource Conservation Service sites #1 and #2 were observed to have been plugged with fine soils. During hand-planting operations, planters tended to push Booth Tubes into the soils, thus creating a very dense plug of fine material at the lower end of the tube. This plug prevented root egress and likely contributed to the death of the seedling. In contrast, the Bingham Canyon site consisted of loose, highly drained gravels and consequently avoided the plugging problem. The plugging problem could easily be resolved by shortening the tube configuration to a 15-cm (6-in.) length that would allow for easier planting.

Despite overall poor survival, conditions at all sites were severely drought impacted and some success was achieved. The Bingham Canyon site represents what may be possible under more moderate growing conditions typical of the areas in which the seedlings were planted. The investigators do concede, however, that this container type may not be suitable for areas in which the mean average precipitation is less than 25-cm (10-in.) annually and sub-soil moisture is absent.

8.4 Ecological Impacts of Irrigating Native Vegetation with Treated Sewage Wastewater

Investigators

Roger D. Blew and Amy D. Forman, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID

Funding Sources

Department of Energy Idaho Operations Office

Background

In 1995, the INEEL began disposing of treated wastewater at the Central Facilities Area (CFA) by applying it to the surface of soils and native vegetation using a center pivot irrigation system. Research conducted on this disposal method at the INEEL provides an opportunity to determine the benefits and/or hazards of disposal of wastewater on native vegetation in arid and semi-arid regions. Results will be applicable to a wide range of municipal, industrial, and agricultural wastewater disposal needs. Because permits to dispose of agricultural and industrial wastewater may have restrictions on application to prevent deep percolation, this research may refine some of the models used to predict the maximum rate of wastewater application possible without percolation below the rooting zone.

The wastewater land application facility at CFA covers approximately 29.5 ha (73 acres). The permit for operating this system limits the application rate to 63.5 cm (25 in.) water per year, which must be applied such that no more than 7.6 cm (3 in.) of water leaches through the root zone toward groundwater. The 63.5-cm (25-in.) maximum application rate is more than two and one-half times the average annual precipitation, and plants may not be able to deplete this water in one growing season to prevent leaching. Most of the precipitation in this cool desert biome comes in the winter and spring. Soil moisture recharge occurs in the spring with snowmelt and rainfall. Wastewater application must be timed to avoid spring recharge to minimize deep percolation of wastewater. The wastewater also contains organic carbon, nitrogen, other nutrients, and trace metals that may have impacts on the proper functioning of native soil-plant systems.

Different plant species respond differently to the addition of water and nutrient elements, especially if those additions come at times of the year that are normally dry. These differences in response can result in some species being favored and others discouraged. Changes in plant community structure can be expected. For example, in arid and semiarid regions grasses are known to dominate where precipitation comes mostly in the summer and shrubs tend to dominate in areas where moisture comes as snow. Summer irrigation may lead to decreases in shrub dominance and increases in grasses.

Changes in plant community structure also mean changing habitats for other organisms such as small mammals, birds, insects, and big game animals. Because the area is relatively small, it is unlikely that decreased habitat quality would have significant impacts on wildlife populations on the INEEL. Increases in habitat quality, however, could have substantial impacts on wildlife use patterns in and near this small area.

Objectives

The primary objective of the research study was to determine the ecological benefits or hazards of applying wastewater on native vegetation in semiarid regions. Specific objectives were to determine the potential for impacts on rangeland quality, resident wildlife populations, and soil water balance.

Accomplishments through 2002

Accomplishments for 2002 include the following:

Plant cover surveys were completed in the three distinct plant community types (sagebrush steppe, crested wheatgrass, and a transition type) on the study area;

Soil moisture data were collected weekly at 20 sites in the wastewater application area and 20 control sites; and

A breeding bird survey was conducted on the study site.

Results

Vegetation -Results from the 2002 vegetation data analyses confirm results from previous years. Sewage wastewater application affects crested wheatgrass communities the least. Similar cover values and similar species composition, as evidenced by high Simplified Morisita's Similarity Index values, support this conclusion. This index returns a value of one for two plant communities that are identical and a value of zero for two communities that have no similar community elements. Crested wheatgrass communities at the INEEL tend to occur as monocultures; thus, crested wheatgrass communities are very homogenous and unlikely to exhibit much spatial variation, even when disturbed.

The vegetation type that represents a transitional zone between the crested wheatgrass community and the sagebrush steppe community was slightly more affected by the irrigation treatment than the crested wheatgrass community. The difference between the irrigated and control transition plots was particularly apparent in the difference in grass cover values between the two treatments. However, the Simplified Morisita's Index value returned for the transitional vegetation type indicates that the species composition between the irrigated and control plots was quite similar.

The greatest differences between the irrigated and control treatments were found in the sagebrush steppe community. Total cover values were substantially different between irrigated and control plots, largely due to very low sagebrush cover in the irrigated treatment. In addition, the Simplified Morisita's index value comparing species composition between the treatments suggests that sewage wastewater application affects sagebrush steppe communities to a greater degree than it affects the other two vegetation types studied here. Sagebrush steppe community vegetation is more likely to fluctuate in response to disturbance or changing environmental conditions because sagebrush steppe communities are much more heterogeneous, and therefore are more likely to vary in space and time. Additionally, a higher species richness value for the sagebrush steppe plots suggests greater potential for niche separation, which increases the potential for vegetation composition change in response to disturbance.

Animals -Breeding bird surveys were conducted on the wastewater application area during June of 2002 following U. S. Geological Survey, Breeding Bird Survey guidelines. A breeding bird survey route stop was established on the application area in 1997 and surveys have been conducted yearly since that time. In 2002, Western meadowlark (Sturnella neglecta) remained the most abundant species. Other common species included brown-headed cowbird (Imolothrus ater), Brewer's Sparrow (Spizella breweri), Brewer's blackbird (Euphagus cyanocelphalus), and horned lark (Eremophila alpestris). One species, sage sparrow (Amphispiza belli), which has been common in the past, was not observed during the 2002 survey. Otherwise, results from the 2002 survey were comparable to previous years and similar to that found on the CFA breeding bird survey route.

Soil Moisture -During the 2002 growing season, soil moisture dynamics were similar between irrigated and control soil profiles within the crested wheatgrass community. Both the irrigated and control soil profiles demonstrated a spring infiltration event in which the soil moisture wetting front reached approximately one meter (3.2 ft). Water redistribution throughout the soil profile was evident through the end of April. Subsequent to this, soil moisture decreased steadily throughout the wetted profile through the summer as a result of evapotranspiration. Soils began to approach the lower limit of extraction by August in 2002.

The soil moisture profiles do not indicate an increase in soil moisture at 20 cm (7.9 in.) or deeper due to wastewater application. If irrigation were to affect soil moisture, we would expect to see either small wetting fronts in the profile throughout the summer (in the case of pulses in application), or we would expect soil moisture in at least some portion of the top of the soil profile to remain elevated (in the case of relatively steady application of water). Neither of these patterns is apparent in the irrigated crested wheatgrass soil profiles. In fact, those profiles dry down throughout the summer in a manner very similar to that of the control soil profiles. Thus, most of the additional water received by a soil profile through wastewater application is evaporated or transpired before it percolates to a depth of 20 cm (7.9 in.) within the soil profile. It should be noted that it is possible for a small amount of water to move downward through the soil profile, without detectable changes in soil moisture content, because of unsaturated flow. In addition, soil moisture did not change at the bottom of the soil profiles throughout the season at many of the hydroprobe access tube locations, suggesting that any flux through the bottom of the soil profiles would result from unsaturated flow.

As with soil moisture dynamics in the crested wheatgrass vegetation type, no differences in soil moisture profiles between irrigated and control locations are apparent in either the transition or the sagebrush steppe vegetation type. In both transition and sagebrush steppe vegetation, soil moisture profiles in the irrigated locations do not indicate soil moisture increases at the top of the soil profile in response to irrigation, nor does water content at the bottom of the profiles at most access tube locations change. Thus, although changes in vegetation cover and composition between irrigated and control locations vary among vegetation type (i.e., control and irrigated plots within the sagebrush steppe community are more different than control and irrigated plots within the crested wheatgrass community), no such pattern is obvious in soil moisture dynamics. In fact, soil moisture dynamics in irrigated locations do not differ substantially from those in control locations for any of the vegetation types. Therefore, the probability of water percolating through the rooting zone and continuing to move downward was essentially the same for the wastewater application area and control locations during the 2002 growing season.

8.5 Natural and Assisted Recovery of Sagebrush (Artemisia tridentata) in Idaho’s Big Desert: Effects of Seeding Treatments and Livestock Grazing on Successional Trajectories of Sagebrush Communities

Investigators

Mike Pellant, Idaho State Office of the Bureau of Land Management, Boise, ID

Roger D. Blew and Amy D. Forman, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID

Robert Jones, Department of Energy Idaho Operations Office, Idaho Falls, ID

Greg White, Idaho National Engineering and Environmental Laboratory, Bechtel BWXT Idaho, LLC, Idaho Falls, ID

Trish Klahr and Alan Sands, The Nature Conservancy, Boise, ID

Gregg Dawson, Upper Snake River District Bureau of Land Management, Idaho Falls, ID

Funding Sources

Bureau of Land Management

U.S. Department of Energy Idaho Operations Office

The Nature Conservancy

Background

Averaged over the last ten years, approximately 95,000 ha (235,000 acres) of lands managed by the Bureau of Land Management (BLM) in Idaho have burned annually. The BLM and other managers of Idaho rangelands, including the INEEL, must decide whether the burned areas need stabilization and rehabilitation treatments to prevent soil erosion and inhibit the invasion of exotic species such as cheatgrass (Bromus tectorum). Most of these rangelands have historically been dominated by big sagebrush (Artemisia tridentata), which does not resprout after fire. Sagebrush provides critical food and habitat for sage grouse, a species proposed for listing under the Endangered Species Act. With the accelerating loss of native sagebrush communities and habitat for sage grouse and other sagebrush-obligate species, sagebrush reseeding following fire has become an important consideration, as has the issue of livestock grazing impacts on recovering native vegetation and seeded areas. In the last three years approximately 70 percent of the sage grouse habitat in eastern Idaho's Big Desert has been burned by wildfire. Fire suppression and rehabilitation costs are rising, and the threats to human life and property are increasing in eastern Idaho.

This study has been divided into three components to address management concerns relative to: (1) native plant recovery in good ecological condition rangeland, (2) success of aerial seeding sagebrush, and (3) whether livestock grazing affects recovery on sagebrush steppe rangelands. These three components will provide new scientific information that addresses current management concerns relative to wildfire impacts and rehabilitation treatments on the eastern Snake River Plain. These studies are designed to establish long-term, replicated monitoring sites that can be reread in the future to provide additional information to managers about post-fire recovery and rehabilitation success. These studies will also provide insight into restoring sagebrush and understory herbaceous species for sage grouse and other sagebrush obligate wildlife species and domestic livestock in the Great Basin.

Objectives

The overall objectives of the proposed research are to examine some of the key factors that influence trajectories of community diversity and structure following wildfire in sagebrush-steppe ecosystems. Specifically, the factors that influence the recovery of these systems following fire and the replacement of native plant communities with vegetation dominated by cheatgrass (Bromus tectorum) will be examined. In 2002, research began to examine three basic research objectives:

Describe post-wildfire trajectories in community composition and structure in areas in good ecological condition;

Compare sagebrush recruitment on areas that have been aerially seeded to areas relying on natural recruitment processes; and

Determine whether trajectories of community composition and structure differ between areas returned to grazing after fire and areas where grazing is excluded.

Accomplishments through 2002

To address the second objective, surveys for sagebrush seedlings were conducted along transects 1000-m (3281-ft) in length. Surveys were conducted May 9 and 10, 2002.

To address the first and third objectives, paired research plots were established in a portion of the area burned by the 2000 Tin Cup Fire. Grazing enclosure fences were constructed around one plot from each pair. The enclosed plot will be used to address questions related to recovery of vegetation in ungrazed sagebrush steppe rangeland. The unfenced plot will be used to examine the role of livestock grazing on that recovery. In all of these plots, plant cover, species richness and diversity were measured. Permanent photoplots and photopoints were established and photographed.

Results

Seedling Survey -Investigators found a total of 12 individual seedlings in three groups. All three groups were on one of the planted lines in the ungrazed area. However, all three groups were near (1, 20, and 65 m [3.2, 66 and 213 ft]) and downwind of surviving mature sagebrush plants. Because of the proximity to surviving sagebrush plants, we could not unequivocally conclude that they resulted from the February 2001 aerial planting.

Species Richness, Density and Frequency -A total of 78 plant species were encountered in the ten pairs of plots (20 plots). Eleven of those were nonnative species. Three of the ten pairs of plots contained no nonnative species. Species richness ranged from 23 to 49 species per plot. Indian rice grass (Achnatherum hymenoides), green rabbitbrush (Chrysothamnus viscidiflorus), tapertip hawksbeard (Crepis acuminata), squirreltail (Elymus elymoides), and Hood's phlox (Phlox hoodii) were found in all of the plots. Narrowleaf goosefoot (Chenopodium leptophyllum), shaggy fleabane (Erigeron pumilus), desert biscuit root (Lomatium foeniculaceum), and hoary aster (Machaeranthera canescens) occurred in 19 of the 20 plots. Douglas' dusty maiden (Cheanactis douglasii), Wilcox's woolystar (Eriastrum wilcoxii), and blue bunch wheatgrass (Pseudoroegneria spicata) were found in 18 of the 20 plots. Twenty-one species occurred in 15 or more of the 20 plots.

Coefficient of Community is the percentage of total species that the two communities have in common. It was calculated here as to compare the two plots of each pair for similarity in terms of the species present. Coefficient of Community varied from 0.69 to 0.86. These results suggest that most pairs of plots share many of the same species.

Plant Cover -Total plant cover on the paired plots was 11 percent. Shrubs and grass cover were 4.6 and 1.5 percent, respectively. Perennial forb (wildflower) cover was 3.6 percent. Cover by introduced species (weeds) was 0.7 percent.

8.6 The Protective Cap/Biobarrier Experiment: A Study of Alternative Evapotranspiration Landfill Caps for the INEEL

Investigator

Amy D. Forman, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID

Funding Sources

U.S. Department of Energy Idaho Operations Office

Background

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 groundwater 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). The 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 groundwater (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 on the INEEL 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.

Objectives

From the time it constructed, the PCBE has had four primary objectives:

Compare the performance of caps having biobarriers (capillary breaks) with that of soil only caps and that of caps based on U.S. Environmental Protection Agency recommendations for Resource Conservation and Recovery Act caps;

Examine the effects of biobarriers as capillary breaks placed at different depths on water percolation, water storage capacity, plant rooting depths, and water extraction patterns;

Evaluate the performance of caps receiving higher precipitation than expected under either the present climate or that anticipated in the foreseeable future; and

Compare the performance of a community of native species on ET caps to that of caps vegetated with a monoculture of crested wheatgrass.

Specific tasks within the PCBE for 2002 were twofold. The first was to summarize results from the first seven years of data collection (1993-2000) and present those results in a short, concise report to provide guidance to managers, planners, and private contractors involved with the design and construction of protective caps for burial of hazardous waste at the INEEL. The report includes a brief summary of the theory of evapotranspiration caps, a summary of research results on the PCBE and previous capping experiments, and specific recommendations for constructing and maintaining evapotranspiration caps at the INEEL. This report is intended to update the report by Anderson et al. (1991).

The second task of the PCBE in 2002 was to continue irrigation treatments and to continue soil moisture and plant community data collection. These data will be analyzed according to the four major objectives listed above; however, the focus of the project will shift from short-term cap function to longer-term performance issues. For example, emphasis on plant community structure will change from vegetation establishment to long-term changes in community composition as plant communities on the caps continue to develop. The PCBE has one of the most complete, long-term data sets for experimental ET caps, which makes it a model system for studying ET cap longevity.

Results

Results summarized in the short report indicate that the soil only cap and the biobarrier caps generally performed similarly throughout the study period (1993-2000) under ambient precipitation, and all moisture received as precipitation was returned to the atmosphere annually via evapotranspiration. The Resource Conservation and Recovery Act cap occasionally drained, even under ambient precipitation, as a result of water infiltrating to and running off the flexible membrane liner.

Water extraction patterns were similar between vegetation types under ambient precipitation. However, in many years the amount of water in the soil profile at the end of the growing season did significantly differ in response to vegetation type under augmented precipitation treatments.

For example, from 1996-2000, there was more water in the caps planted in crested wheatgrass versus caps planted in native vegetation under augmented summer precipitation. Nevertheless, cap failure on the PCBE has been a rare occurrence under any cap design, vegetation type, and precipitation regime combination.

The initial results of the PCBE from 1993-2000 have indicated that low maintenance; cost-effective ET caps can be used to effectively isolate buried waste at the INEEL. To date, this project has also generated a large amount of data useful for making decisions related to specific capping projects at the INEEL. Longer term data will be used to assess longevity of these caps.

Initial data analyses from the 2002 soil moisture data indicate that the spring wetting front extended to the bottom of the soil profile on several of the plots receiving spring irrigation. A few of those plots likely drained. Those same plots received fall irrigation in October; however, the wetting fronts resulting from that irrigation treatment did not reach the bottom of the soil profile on any of the plots. Thus, a combination of spring infiltration from snowmelt and infiltration from the spring irrigation treatment caused many plots to reach or nearly reach storage capacity. Water in the soil profile was quickly transpired and cap performance was not affected later in the season.

Wetting fronts on ambient and summer irrigated plots never exceeded 1 m (3.2 ft) throughout the year. Thus, all of the water received through precipitation and irrigation on ambient and summer irrigated plots was returned to the atmosphere. These results confirm that a global climate change scenario that includes large increases in winter precipitation (especially precipitation received in late winter or early spring) pose the greatest threat to these cap designs. However, plots at or near storage capacity in the spring are able to recover that storage capacity within one growing season.

Vegetation data from the PCBE in 2002 have not yet been analyzed.

REFERENCES

Anderson J.E., Nowak R.S., Ratzlaff T.D., and Markham O.D., 1991, Managing Soil Moisture On Waste Burial Sites, U.S. Department of Energy, Idaho Operations Office, Idaho Falls, DOE/ID 12123.

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., Bendz D., Hogland W., Rosqvist H., and Akesson M., 1994, “Water Balance for Landfills of Different Age,” Journal of Hydrology, 158:203-217.

Bowerman, A.G., and Redente E.F., 1998, “Biointrusion of Protective Barriers at Hazardous Waste Sites,” Journal of Environmental Quality 27:625-632.

Daniel, D.E. and Gross B.A., 1995, “Caps,” in Assessment Of Barrier Containment Technologies: A Comprehensive Treatment For Environmental Remediation Applications, edited by R.R. Rumer, and J.K. Mitchell, National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia, pp.119-140.

Fisher, J.N., 1986, Hydrogeologic Factors in the Selection of Shallow Land Burial for the Disposal of Low-Level Radioactive Waste, U.S. Geological Survey Circular 973.

Forman, A.D., 2003, Evapotranspiration Caps for the Idaho National Engineering and Environmental Laboratory: A Summary of Research and Recommendations, Stoller-ESER-56, May.

Hakonson, T.E., Lane L.J., and Springer E.P., 1992, “Biotic and Abiotic Processes,” in Deserts as Dumps? The Disposal of Hazardous Materials in Arid Ecosystems, edited by C.C. Reith, and B.M. Thomson, Albuquerque, New Mexico: University of New Mexico Press, pp.101-146.

Nativ, R., 1991, “Radioactive Waste Isolation in Arid Zones,” Journal of Arid Environments, 20:129-140.

Nyhan, J.W., Hakonson T.E., and Drennon B.J., 1990, “A Water Balance Study of Two Landfill Cover Designs for Semiarid Regions,” Journal of Environmental Quality, 19:281-288.

Suter, G.W.I.I., Luxmoore R.J., and Smith E.D., 1993, “Compacted Soil Barriers at Abandoned Landfill Sites are Likely to Fail in the Long Term,” Journal of Environmental Quality, 22:217-226.