Bridger-Teton National Forest Research Articles

Gradient Analysis and Classification of Tall Forb Communities in the Bridger-Teton National Forest, United States

Tall forb−mixed upland−herb communities are exemplified by high plant diversity and a profusion of luxuriant wildflowers throughout subalpine mountain parklands of the interior western United States. These unique and ecologically important communities remain largely unclassified in terms of their biological and physical attributes and ecological responses to management and disturbances. Land managers need respective classifications to evaluate and guide conservation planning and management for tall forb communities where they occur. In this study, 23 sites from four subalpine areas representing reference tall forb plant communities on the Bridger-Teton National Forest were identified and selected for analysis after a sustained cessation of grazing activities. The purpose of the study was to quantitatively examine tall forb community stands and provide a basis for developing a classification system for identifying future ecological sites, which are essential in conservation planning, implementation and management, and monitoring. Seven tall forb cluster groups were identified with unique plant composition and specific environmental gradients (i.e., plant species richness, diversity indices, elevation, average annual precipitation, surficial geology, three-dimensional geomorphic descriptions, soil clay content diversity dynamics, and foliar, ground, and surface cover). Among the seven cluster groups, we identified 31 families, 112 genera, and 158 plant species on the sample sites (61 species representing native indicator reference species, 86 native secondary indicator species, and 10 introduced non-native species). Beta diversity and plant species turnover ranged from 6.7% to 41.9% among the seven cluster groups, indicating discrete differences in plant species assemblages, plant associations, and site dynamics. The seven tall forb clusters are characteristic of specific and unique plant species composition, species diversity, and environmental factors. Therefore, a specialized site approach with respective guidelines is recommended for assessing and conserving discrete tall forb ecological sites and maintaining key dominant native indicator reference species, rangeland health and proper functioning condition, and defined monitoring protocols.

Occupancy modeling of Parnassius clodius butterfly populations in Grand Teton National Park, Wyoming

Estimating occupancy patterns and identifying vegetation characteristics that influence the presence of butterfly species are essential approaches needed for determining how habitat changes may affect butterfly populations in the future. The montane butterfly species, Parnassius clodius, was investigated to identify patterns of occupancy relating to habitat variables in Grand Teton National Park and Bridger-Teton National Forest, Wyoming, United States. A series of presence–absence surveys were conducted in 2013 in 41 mesic to xeric montane meadows that were considered suitable habitat for P. clodius during their flight season (June–July) to estimate occupancy (ψ) and detection probability (p). According to the null constant parameter model, P. clodius had high occupancy of ψ = 0.78 ± 0.07 SE and detection probability of p = 0.75 ± 0.04 SE. In models testing covariates, the most important habitat indicator for the occupancy of P. clodius was a strong negative association with big sagebrush (Artemisia tridentata; β = − 21.39 ± 21.10 SE) and lupine (Lupinus spp.; β = − 20.03 ± 21.24 SE). While P. clodius was found at a high proportion of meadows surveyed, the presence of A. tridentata may limit their distribution within montane meadows at a landscape scale because A. tridentata dominates a large percentage of the montane meadows in our study area. Future climate scenarios predicted for high elevations globally could cause habitat shifts and put populations of P. clodius and similar non-migratory butterfly populations at risk.

Serological Survey for Antibodies to Mosquito-Borne Bunyaviruses Among US National Park Service and US Forest Service Employees

Serum samples from 295 employees of Great Smoky Mountains National Park (GRSM), Rocky Mountain National Park (ROMO), and Grand Teton National Park with adjacent Bridger-Teton National Forest (GRTE-BTNF) were subjected to serological analysis for mosquito-borne bunyaviruses. The sera were analyzed for neutralizing antibodies against six orthobunyaviruses: La Crosse virus (LACV), Jamestown Canyon virus (JCV), snowshoe hare virus (SSHV), California encephalitis virus, and Trivittatus virus (TVTV) belonging to the California serogroup and Cache Valley virus (CVV) belonging to the Bunyamwera serogroup. Sera were also tested for immunoglobulin (Ig) G antibodies against LACV and JCV by enzyme-linked immunosorbent assay (ELISA). The proportion of employees with neutralizing antibodies to any California serogroup bunyavirus was similar in all three sites, with the prevalence ranging from 28% to 36%. The study demonstrated a seroprevalence of 3% to CVV across the three parks. However, proportions of persons with antibodies to specific viruses differed between parks. Participants residing in the eastern regions had a higher seroprevalence to LACV, with 24% (18/75) GRSM employees being seropositive. In contrast, SSHV seroprevalence was limited to employees from the western sites, with 1.7% (1/60) ROMO and 3.8% (6/160) GRTE-BTNF employees being positive. Seroprevalence to JCV was noted in employees from all sites at rates of 6.7% in GRSM, 21.7% in ROMO, and 15.6% in GRTE-BTNF. One employee each from ROMO (1.7%) and GRTE-BTNF (1.9%) were positive for TVTV. This study also has illustrated the greater sensitivity and specificity of plaque reduction neutralization test compared to IgG ELISA in conducting serosurveys for LACV and JCV.

Infection with Colorado tick fever virus among humans and ticks in a national park and forest, Wyoming, 2010.

Colorado tick fever (CTF) is an underreported tick-borne viral disease occurring in the western United States. CTF illness includes fever, headache, and severe myalgia lasting for weeks. Wyoming has one of the highest CTF incidence rates with approximately 30% of infected persons reporting tick exposure in a Wyoming National Park or Forest before symptom onset. We assessed CTF virus infections among humans and Dermacentor andersoni ticks in Grand Teton National Park (GRTE) and Bridger-Teton National Forest (BTNF). In June of 2010, 526 eligible employees were approached to participate in a baseline and 3-month follow-up serosurvey and risk behavior survey. Seropositivity was defined as antibody titers against CTF virus ≥10, as measured by the plaque reduction neutralization test. Ticks were collected at 27 sites within GRTE/BTNF and tested by RT-PCR for the CTF virus. A total of 126 (24%) employees participated in the baseline and follow-up study visits. Three (2%) employees were seropositive for CTF virus infection at baseline. During the study, 47 (37%) participants found unattached ticks on themselves, and 12 (10%) found attached ticks; however, no participants seroconverted against CTF virus. Walking through sagebrush (p=0.04) and spending time at ≥7000 feet elevation (p<0.01) were significantly associated with tick exposure. Ninety-nine percent (174/176) of ticks were D. andersoni, and all were found at ≥7000 feet elevation in sagebrush areas; 37 (21%) ticks tested positive for CTF virus and were found at 10 (38%) of 26 sites sampled. Although no GRTE or BTNF employees were infected with CTF virus during the study period, high rates of infected ticks were identified in areas with sagebrush at ≥7000 feet. CTF education and personal protection measures against tick exposure should be targeted to visitors and employees traveling to the high-risk environs identified in this study.

There Will Be Bears by Ryan Gebhart (review)

Reviewed by: There Will Be Bears by Ryan Gebhart Elizabeth Bush Gebhart, Ryan. There Will Be Bears. Candlewick, 2014. 217p. ISBN 978-0-7636-6521-0 $16.99 R Gr. 5-7. For Tyson, the highlight of turning thirteen was to be the long-promised opportunity to shoot and field-dress his first elk on a trip to Bridger-Teton National Forest with Gramps. What Tyson gets instead is the news that Gramps is experiencing kidney failure and is moving to a nursing home where he can get affordable dialysis—oh, and Gramps isn’t really Tyson’s blood relative, but his dad’s stepfather. That all this is revealed in a tardy, roundabout fashion leaves Tyson feeling betrayed: “It’s one thing for Mom and Dad to treat me like a kid—they’re stupid. But Gramps couldn’t tell me?” His love for Gramps, however, is enduring and his desire to go through with the trip unshakeable, so the pair plots a way to sneak off between treatments for a brief stint in the mountains. It’s a pretty insane idea, fraught not only with danger to Gramps’ fragile health but also with the very real threat from a rogue grizzly that has mauled tourists and hunters over the past few weeks. The book is strongly written, and Tyson’s emotional turmoil, which he glibly covers with barbed observations and self-deprecating humor, is painfully real. The gorily precise details of the elk kill and butchering also add compelling dimension to a familiar story of coming to terms with the debility of a beloved grandparent. Family stories and adventure tales are often relegated to separate pigeonholes, and this title offers fresh crossover appeal. Copyright © 2014 The Board of Trustees of the University of Illinois

Quantifying the Threat of Unsuppressed Wildfires Reaching the Adjacent Wildland-Urban Interface on the Bridger-Teton National Forest, Wyoming, USA

An important objective for many federal land management agencies is to restore fire to ecosystems that have experienced fire suppression or exclusion over the last century. Managing wildfires for resource objectives (i.e., allowing wildfires to burn in the absence of suppression) is an important tool for restoring such fire-adapted ecosystems. To support management decisions that allow wildfires to burn unsuppressed, land managers need a quantitative assessment of the potential for such wildfires to reach nearby fire-susceptible resources and assets. We established a study area on a portion of the Bridger-Teton National Forest near Jackson, Wyoming, USA, where land managers wish to restore fire by managing wildfires, but are concerned about the threat to residential buildings. We modeled the ignition and unsuppressed growth of wildfires starting in a remote portion of the study area using FSim, a fire occurrence, growth, and suppression simulation model. We then characterized annual area burned and the likelihood that wildfires would reach a nearby wildland-urban interface (WUI) defense zone. Early-season fires burned longer and grew larger than late-season fires, and thus had a higher likelihood of reaching the WUI zone (3 % of May fires compared to 0.1 % of October fires). Because fire managers do not anticipate managing all fire starts for resource objectives, we applied a simple rule set termed “RO rules,” indicating the fraction of starts by month to be managed for resource objectives. This reduced the expected number of fires reaching the WUI zone by 70 %, and the expected WUI zone area burned by 61 %. From 1990 to 2009, a mean of 207 ha yr−1 had been burned by wildfires starting in the remote portion of the study area. By contrast, we estimated that 14 431 ha yr−1 could burn if no fire starts were suppressed, and 4861 ha yr−1 after applying the RO rules. Our analysis approach can be extended to determine which parts of the landscape are most likely to produce fires that reach specific targets on the landscape.

Landslide Soils and Geomorphology in Bridger-Teton National Forest, Northwest Wyoming

Active landslides are evident throughout Bridger-Teton National Forest (BTNF), and northwestern Wyoming has one of the highest landslide densities in the country. Land use changes and increased demands for infrastructure challenge BTNF personnel to better understand landslide processes in order to make informed land management decisions. Despite recent population growth in the region, research on landslide phenomena is lacking. In this study, soil and geomorphic properties related to landslide occurrence were studied at 18 landslides in the BTNF. Landslides were categorized as active or inactive based on geomorphic features. Landslide soil characteristics including texture, shrink-swell potential, clay mineralogy, and horizonation were compared on active and inactive landslides. The results indicate that soil characteristics related to the degree of soil formation are different on active and inactive landslides. Soil characteristics such as plasticity, shrink-swell potential, and clay mineralogy influence slope stability and were distinctly different on active and inactive landslides, especially in C horizons. This study shows that soil characteristics and slope geomorphic properties may be useful for assessing landslide frequency. Our results support a hypothesis that landslide occurrence in the BTNF is related to weathering of soil and unconsolidated material, which affects clay mineralogy.

Sheep Grazing in National Forest Wilderness

The Bridger Wilderness of Bridger-Teton National Forest takes up most of the west slope of the Wind River Mountains in western Wyoming. Within the wilderness boundary lies the tallest of Wyoming's mountains, Gannett Peak; the Green River, a major tributary of the Colorado, begins here. But Bridger Wilderness is more than big mountains and important headwaters; it is a battleground for old adversaries who have struggled to direct the use of America's wildlands, and who compete to influence the federal agency charged with administering this piece of public land (Figure 1). The livestock industry, environmentalists, and the US Forest Service are the players in this battle. And though this particular battleground is shaped by uniquely American institutions and history, the contest itself is one that can be found around the globe.

Modeling Spatial and Temporal Dynamics of Montane Meadows and Biodiversity in the Greater Yellowstone Ecosystem

We used remotely sensed imagery to identify and map montane meadow types (M-types) along a moisture gradient, and to develop spectrally-based spatially-explicit models for predicting species diversity patterns in two regions of the Greater Yellowstone Ecosystem: 1) Grand Teton National Park and Bridger Teton National Forest and 2) the Gallatin National Forest and Yellowstone National Park. We investigated the potential to predict species assemblages associated with these meadow types and we also tested our ability to classify specific subsets of montane meadow types such as wetland and sagebrush communities. We also compared our results to the predictability of communities when our sampling sites were classified by GAP analysis. We classified wetlands into 2 categories that differed by the percentage of obligate wetland plant species. Accuracy of wetland classification based upon remotely sensed data was 70%. We classified 4 sagebrush communities [low sagebrush (Artemesia arbuscula), big sagebrush (Artemesia tridentata ssp. vaseyana), mixed low sagebrush/big sagebrush, and bitterbrush (Purshia tridentata)/big sagebrush]. Overall accuracy of our sagebrush community classification based upon remotely sensed data was 65%, and was highest for the mixed big sagebrush/low sagebrush community at 86%. We also investigated the association of plant, bird and butterfly species with each of the meadow types. Because of the rarity of many of the species, our analyses focused on species for which we had minimum standards of data. These standards varied among taxonomic groups, but species only observed infrequently were not included in the analyses. The abundances of 6 of the 11 most abundant bird species were significantly correlated with meadow type as defined by satellite imagery. However, 10 out of 11 bird species showed a significant correlation when both remotely sensed data and landscape variables (e.g., shrub biomass, percent cover of willow or sagebrush, and meadow area) were added to the models. Butterfly species showed even stronger associations with particular meadow types, especially in the Teton region. We used regression tree analyses to separate meadow types by their associated species of butterflies. Fourteen of 67 butterfly species distribution patterns could be used to classify sampling sites into one of five different meadow types with 92% accuracy in 1997 and 96% accuracy in 1998. From the perspective of global climate change indicators, mesic meadows showed the greatest seasonal and interannual variability in spectral response and highest species diversity of plants. Given the rich biodiversity of mesic montane meadows and their sensitivity to variations in temperature and moisture, they may be important to monitor in the context of environmental change. Finally, we were able to do some additional related studies funded by a grant from the Nature Conservancy's David H. Smith Fellowship program (to Su and Debinski). We compared the scale of mapping of biotic communities in the EPA-funded project with the GAP analysis approaches in Montana and Wyoming. We found that both the 1 ha MMU M-Type map and 100 ha MMU Wyoming GAP map were significantly associated with bird, butterfly and plant community similarity. However, the 2 ha Montana GAP map was not associated with bird and plant community similarity and only discriminated differences in butterfly species composition between one map class and the others. This difference is probably explained by the fact that Montana GAP had a coarser categorical resolution of meadow types which was not sensitive to community variation associated with the hydrology of the meadows.

Coyote (Canis latrans) Habitat use and Mortality in Grand Teton National Park and Suburban-Agricultural Areas of Jackson Hole, Wyoming

A study of coyote (Canis latrans) habitat use and mortality in Grand Teton National Park and the suburban-agricultural land surrounding Jackson, WY was conducted between September 1999 and August 2000. This research focused on the influence of human development, habitat type, topography, and simulated wolf presence on coyote habitat use and on coyote mortality patterns in undeveloped and suburban-agricultural land. The overall goal of this project was to provide baseline information on the coyote population in Jackson Hole that can be used in the future to determine what, if any, impact wolves and human developments may have on coyotes. There were a total of fifteen radio-collared coyotes in the suburban-agricultural area and fourteen radio collared coyotes in Grand Teton National Park and adjacent areas in the National Elk Refuge and Bridger-Teton National Forest. Marked coyotes were tracked weekly using short interval telemetry relocations and triangulation to determine habitat use patterns. During the winter, track transects were skied weekly and coyote trails were backtracked and mapped using hand held GPS units to determine fine scale habitat use patterns. Coyote mortality was determined via telemetry and direct observation. Preliminary data analyses suggest that coyotes use mainly sagebrush-grasslands or forest-shrub-grass edge areas and avoid forest interior areas. Coyotes frequently use trails and roads in the undeveloped area when moving long distances. Preliminary analysis also indicates that roads and trails are used in a greater proportion than their abundance on the landscape. Coyotes were frequently observed using riparian corridors to move between open meadows in the suburban-agricultural area. There is some evidence that suggests coyotes selectively travel fences and irrigation ditches for long distances in agricultural areas. The movement data also suggests that coyotes avoid developed areas during the day and travel in these developed areas at night. The data on coyote locations suggests some avoidance of wolf urine scent grids in the undeveloped area, but not in the developed area. Coyote mortality was primarily human caused, and coyotes that were male, transient, and lived in the suburban-agricultural area were the most commonly killed animals.

Neonatal Mortality of Elk in Areas With and Without Grizzly Bears

The Greater Yellowstone Ecosystem (GYE) may support the densest populations of elk in North America, and a diverse community of large carnivores that prey on elk. From 1984 to 1996, the Jackson elk herd doubled in size exceeding its winter population objective of 11,000 elk by nearly 7,000 animals (Smith and Anderson 1998). In and adjacent to Grand Teton National Park (GTNP), mortality of neonatal elk averaged 15% annually during 1990-1992 (Smith and Anderson 1996). Predation by black bears and coyotes, when calves were less than 4 weeks of age, caused 68% of neonatal mortality. Calves killed by mountain lions were more than 4 months old. Except for hunting, predation was the largest source of mortality of radio­collared elk from birth through adulthood. After 1992, grizzly bear activity on federal cattle grazing allotments in eastern GTNP and the adjacent Spread Creek drainage of the Bridger-Teton National Forest (the East Study Area or East SA) markedly increased as did cattle losses to bears. Personnel of the Wyoming Game and Fish Department attributed 26 cattle losses (25 calves, 1 cow) in the East SA in 1993 to grizzly bear predation (Wyoming Game and Fish Department 1995). The Wyoming Game and Fish Commission, which compensates cattle producers for losses due to grizzly predation, initiated a study in 1994 to quantify the proportion of cattle losses in the East SA due to grizzly predation. One grizzly bear documented killing cattle each year, was captured and euthanized in GTNP in 1996. Grizzly bears are opportunistic omnivores that consume both plant and animal foods (Blanchard et al. 1992). Grizzly bear predation on elk calves less than 4 weeks of age was the primary cause of mortality of calves and a major factor regulating the size of Yellowstone National Park's northern elk herd (Singer et al. 1997). Smith and Anderson (1996) found no evidence of grizzly predation on Jackson elk during 1990-1992. However, mid-summer calf:cow ratios of elk in the Spread Creek area of eastern GTNP declined after 1993. We initiated this study in 1997 to compare causes of elk calf mortality in the grizzly-occupied East SA and the relatively grizzly-free area of GTNP west of the Snake River (West SA). The objectives were to: determine: 1) if grizzly bears were preying on elk calves, 2) whether such mortality was compensatory or additive to other sources of mortality, 3) if changes in neonatal mortality altered the harvestable surplus of elk from the Jackson elk herd for hunters, and 4) any influence of environmental factors, and physiological status on survival of elk neonates.

The Effects of Suburban Development and Wolf (Canis lupis) Recolonization on Coyotes (Canis latrans) in Jackson Hole, Wyoming

A comparative study of coyote (Canis latrans) home range, activity, habitat use, and diet in Grand Teton National Park (GTNP) and residential/agricultural areas surrounding Jackson, Wyoming was begun in May 1998 and will continue until August 1999. Twenty-seven coyotes were captured and fitted with radio collars equipped with activity and mortality sensors. Eleven of the coyotes reside in and around the residential/agricultural areas while 15 of the coyotes range from Moran Junction south to the National Elk Refuge. One coyote has remained in Bridger-Teton National Forest near Upper Slide Lake. Marked coyotes were monitored three times a week in the summer and two times a week during the winter via radio telemetry. Preliminary data suggests that the home range size of coyotes in GTNP is larger than that of coyotes in developed areas. Activity levels appear to be lower in residential/agricultural areas during daylight hours. Coyote diet is currently being assessed via scat dissection, and prey availability was determined using Sherman live traps during the summer and early fall. Habitat use will be determined by overlaying coyote home ranges onto habitat maps. Vegetation plots were conducted in five habitat types (aspen, conifer, grass, riparian, sage) to determine vegetation structure. All of the above methods will be repeated in summer 1999. During winter 1999, telemetry surveys and scat collection will continue. Additionally, snow tracking surveys and coyote observations will be conducted to determine coyote group size and behavior. If time allows, relative density estimates and social organization will be determined. The intention of this study is also to collect baseline data on coyotes before and during wolf (Canis lupus) recolonization of Jackson Hole.

Neonatal Mortality of Elk in Areas With and Without Grizzly Bears

The Greater Yellowstone Ecosystem (GYE) may support the densest populations of elk in North America, and a diverse community of large carnivores that prey on elk. The Jackson elk herd has doubled in size since 1984 and currently exceeds its winter population objective of 11,000 elk by about 5,000 animals (Smith and Anderson 1998). In and adjacent to Grand Teton National Park (GTNP), mortality of neonatal Jackson elk averaged 15% annually during 1990-1992 (Smith and Anderson 1996). Predation by black bears and coyotes, when calves were less than 4 weeks of age, caused 68% of neonatal mortality. Calves killed by mountain lions were more than 4 months old. Except for hunting, predation was the largest source of mortality of radio­collared elk from birth through adulthood. Since 1992, grizzly bear activity on federal cattle grazing allotments in eastern GTNP and the adjacent Spread Creek drainage of the Bridger-Teton National Forest (the East Study Area or East SA) has markedly increased and cattle losses to bears have become common. Personnel of the Wyoming Game and Fish Department attributed 26 cattle losses (25 calves, 1 cow) in the East SA in 1993 to grizzly bear predation. The Wyoming Game and Fish Commission, which compensates cattle producers for losses due to grizzly predation, initiated a study in 1994 to quantify the proportion of cattle losses in the East SA due to grizzly predation. One grizzly bear that was documented killing cattle each year, was captured and euthanized in GTNP in 1996.

Neonatal Mortality of Elk in Areas with and without Grizzly Bears

The Greater Yellowstone Ecosystem (GYE) may support the densest populations of elk in North America, and a diverse community of large carnivores that prey on elk. The Jackson elk herd has doubled in size since 1984 and currently exceeds its winter population objective of 11,000 elk by about 5,000 animals (Smith and Anderson 1998). In and adjacent to Grand Teton National Park (GTNP), mortality of neonatal of Jackson elk averaged 15% annually during 1990-1992 (Smith and Anderson 1996). Predation by black bears and coyotes, when calves were less than 4 weeks of age, caused 68% of neonatal mortality. Calves killed by mountain lions were more than 4 months old. Except for hunting, predation was the largest source of mortality of radio-collared elk from birth through adulthood. Since 1992, grizzly bear activity on federal cattle grazing allotments in eastern GTNP and the adjacent Spread Creek drainage of the Bridger-Teton National Forest (the East Study Area or East SA) has markedly increased and cattle losses to bears have become common. Personnel of the Wyoming Game and Fish Department attributed 26 cattle losses (25 calves, 1 cow) in the East SA in 1993 to grizzly bear predation. The Wyoming Game and Fish Commission, which compensates cattle producers for losses due to grizzly predation, initiated a study in 1994 to quantify the proportion of cattle losses in the East SA due to grizzly predation. One grizzly bear documented killing cattle each year, was captured and euthanized in GTNP in 1996.

Postfire Plant Establishment: The Effects of Environment, Prefire Vegetation, Fire Severity, and Landscape Position in Grand Teton National Park

Observations in the Rocky Mountains and elsewhere indicate that vegetation patterns that develop soon after forest fires vary considerably. This variability is evident even on sites that have similar environmental conditions. The causes of this heterogeneity are not well known, but it is now recognized that the conditions present soon after fire, and the plants that become established initially, influence the nature of the vegetation over the next 100-200 years or more (Glenn-Lewin et al. 1992). Our research investigates the causes of the variability in vegetation establishment following fire in Grand Teton National Park and the Bridger Teton National Forest. The specific objectives of our research are as follows: 1) determine the range of variability in the patterns of early postfire succession; 2) determine which environmental and historical variables are most important in controlling vegetation development following fire; 3) elucidate the importance of landscape position and between-patch interactions during early postfire succession; 4) develop a series of multivariate models that will predict the characteristics of early succession in different situations; and 5) project the most probable trajectories of each pioneer community type.

Consequences of the Extirpation of Predators on Moose

This year was the first of our five year project. We established three primary study areas to examine possible biological effects of large predators on moose. Sites where fieldwork was conducted included apparent heavy predation by grizzly bears [the eastern slopes of the Talkeetna Mountains (Alaska)], little or no predation (Grand Teton National Park), and human predation (Bridger-Teton National Forest), the latter two in the southern portion of the Greater Yellowstone Ecosystem. Data were gathered in Alaska from April until August and, in Wyoming, for all months from February until August (except during April). At the southern Greater Yellowstone sites, information was collected on pregnancy rates, calf production, twinning, and juvenile and adult survivorship. Ecological and behavioral data gathered from all three sites included home range locations, foraging associations and rates, habitat use, group size, social interactions, migration, and responses to humans and potential predators. Twenty animals were radio-collared at the Wyoming site; as of December 1995 only 15 survived. One apparently starved to death, one was poached, one was legally shot, and two died of unknown causes. We improved our sample by using 13 females previously radio-collared on national forest lands by University of Wyoming and Wyoming Department of Game and Fish personnel. Of these, two died during the 1994-1995 winter and three had slipped their collars.

Postfire Plant Establishment: The Effects of Environment, Prefire Vegetation, Fire Severity, and Landscape Position

The initial species composition and conditions following disturbance are crucial to determining the long-term development of vegetation (Egler 1954, Glenn-Lewin et al. 1992). Thus, an understanding of early succession can provide insights into the mosaic of vegetation types that will emerge on a landscape. Observations in the Rocky Mountains and elsewhere indicate that postfire vegetation patterns vary considerably. It is now known that numerous factors simultaneously contribute to the species composition of pioneer vegetation (Stahelin 1943, Cattelino et al. 1979, Glenn-Lewin 1980, Noble and Slatyer 1980, Keever 1983, Walker and Chapin 1987, Pickett 1989, Westoby et al. 1989, Glenn-Lewin et al. 1992), and often different patterns of early succession are possible even on sites that are similar. While research on the distribution of late successional vegetation along environmental and disturbance gradients has been a dominant theme in plant ecology (Daubenmire 1943, Whittaker 1956, Despain 1973, Loope and Grueii 1973, Whipple and Dix 1979, Peet 1981, Romme and Knight 1981, Wentworth 1981, Veblen 1986, Allen and Peet 1990), few studies have directly investigated the factors that affect the distribution of pioneer plant communities. Moreover, the influence of landscape structure on the development of vegetation mosaics has only recently been considered (Milne and Forman 1986, Turner et al. unpublished manuscript). Studies designed to understand vegetation patterns following disturbance could be improved by considering site history and the character of the surrounding landscape as well as the effects of site features. We have initiated research to consider the effect of various spatial, historical and site factors on early postfire vegetation in Grand Teton National Park (GTNP) and the adjcent Bridger-Teton National Forest. Specifically, we are studying the relationships between characteristics of early succession and fire severity, geologic substrate, soil characteristics, mean burn patch size, prefire canopy composition, cone serotiny, topographic position, distance to unburned vegetation, and the vegetation composition and fire severity of the surrounding landscape. Our research objectives are to: 1) determine the range of variability in the patterns of early postfire succession 2) determine which environmental and historical variables are most important in controlling vegetation development following fire 3) elucidate the importance of landscape position and between-patch interactions during early postfire succession 4) develop a series of multivariate models that will predict the characteristics of early succession in different situations; 5) project, based on existing literature, the most probable trajectories of each pioneer community type. An important component of our research is to examine the influence of landscape context on early successional vegetation. Understanding and predicting the behavior of organisms requires the consideration of a broad environmental matrix, not simply the autecology of the organisms (Rowe 1981). According to Glenn-Lewin and van der Maarel (1992), spatial attributes such as landscape complexity, community isolation, and the spatial scale of disturbance are important factors influencing succession. We will use GRASS-GIS, to better understand the relationship between site characteristics and pioneer vegetation pattern (Davis and Dozier 1990, Davis and Goetz 1990) as well as to elucidate the importance of landscape position in early succession.

A Logistic Model for the Cumulative Effects of Human Intervention on Bald Eagle Habitat

We developed a logistic model based on a conjoint analysis approach to evaluate the cumulative effects of selected forms of human disturbance on bald eagles (Haliaeetus leucocephalus) in their natural habitat. The dependent variables were amount of habitat available to bald eagles for foraging and perching as a function of 5 human disturbance factors. Application of the model to a section of the Snake River in Grand Teton National Park where detailed information on levels of human intervention were known yielded reasonable values when compared to field observations. The model is currently in use by managers of the Bridger-Teton National Forest and Grand Teton National Park

Development and Application of a Statistical Model for the Cumulative Effects of Human Intervention on Bald Eagle Habitat in the Grand Teton National Park

The research underway has three primary objectives. The first of these is to test the transferability of the cumulative effects model (CEM) developed for the Bridger-Teton National Forest to the Grand Teton National Park. The second major objective is the development of computer software which will easily implement the CEM into the management decision process. For this objective it is necessary that the software be available on standard personal computers, that it provide appropriate tables and graphics suitable for reports, and that it be flexible in terms of the range of "what if" questions that might be posed by the manager. The last objective is to implemant the CEM and the computer package developed to assess the bald eagle habitat in Grand Teton National Park.

Of Grizzly Bears and Commercial Outfitters in Bridger-Teton National Forest, Wyoming

Of Grizzly Bears and Commercial Outfitters in Bridger-Teton National Forest, Wyoming