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Flaw leads (FLs) and polynyas are recurrent areas of open water within sea ice that provide habitat for a diversity of Arctic species. The western Hudson Bay FL is a major, predictable habitat feature; however, its importance to polar bears Ursus maritimus has not been examined. We mapped the FL using synthetic aperture radar (resolution 62.3 × 121 m) from December to May, 2009-2018, and assessed FL use by 73 adult female polar bears tracked using satellite telemetry. Maximum FL width varied from 4 km in March to 145 km in May. Bears were closest to the FL in May, which coincided with their hyperphagic period and the seal pupping season. Only 31.5% (n = 23) of the bears used the FL, and they travelled faster, with lower turning angles along the FL (16° turns at 101° and -69° relative to the FL), suggesting the feature acted as a corridor that could increase prey encounters. Bears were closer to and crossed sections of the FL that were 68% narrower than those not crossed, indicating that a wider FL deters crossing. Abundant prey likely attracts some bears to the FL, but most bears avoid the FL between hunts, likely to conserve energy on consolidated ice or to reduce intraspecific interactions. Increases in open water resulting from climate warming might make the FL more challenging for bears to cross, but could make it more attractive if open-water prey densities increase.

Aim The influence of humans on large carnivores, including wolves, is a worldwide conservation concern. In addition, human‐caused changes in carnivore density and distribution might have impacts on prey and, indirectly, on vegetation. We therefore tested wolf responses to infrastructure related to natural resource development (i.e., human footprint). Location Our study provides one of the most extensive assessments of how predators like wolves select habitat in response to various degrees of footprint across boreal ecosystems encompassing over a million square kilometers of Canada. Methods We deployed GPS‐collars on 172 wolves, monitored movements and used a generalized functional response (GFR) model of resource selection. A functional response in habitat selection occurs when selection varies as a function of the availability of that habitat. GFRs can clarify how human‐induced habitat changes are influencing wildlife across large, diverse landscapes. Results Wolves displayed a functional response to footprint. Wolves were more likely to select forest harvest cutblocks in regions with higher cutblock density (i.e., a positive functional response to high‐quality habitats for ungulate prey) and to select for higher road density in regions where road density was high (i.e., a positive functional response to human‐created travel routes). Wolves were more likely to use cutblocks in habitats with low road densities, and more likely to use roads in habitats with low cutblock densities, except in winter when wolves were more likely to use roads regardless of cutblock density. Main conclusions These interactions suggest that wolves trade‐off among human‐impacted habitats, and adaptively switch from using roads to facilitate movement (while also risking encounters with humans), to using cutblocks that may have higher ungulate densities. We recommend that conservation managers consider the contextual and interacting effects of footprints when assessing impacts on carnivores. These effects likely have indirect impacts on ecosystems too, including on prey species., We deployed GPS‐collars on 172 wolves and evaluated resource selection across boreal ecosystems encompassing over a million square kilometers of North America. Wolves traded‐off among human impacted habitats, and more specifically adaptively switch from using roads to facilitate movement (while also risking encounters with humans), to using cutblocks that may have higher ungulate densities. We therefore recommend that conservation managers consider the contextual and interacting effects of human footprints when assessing impacts on carnivores and on their prey.

Migration of ungulates (hooved mammals) is a fundamental ecological process that promotes abundant herds, whose effects cascade up and down terrestrial food webs. Migratory ungulates provide the prey base that maintains large carnivore and scavenger populations and underpins terrestrial biodiversity (fig. S1). When ungulates move in large aggregations, their hooves, feces, and urine create conditions that facilitate distinct biotic communities. The migrations of ungulates have sustained humans for thousands of years, forming tight cultural links among Indigenous people and local communities. Yet ungulate migrations are disappearing at an alarming rate (1). Efforts by wildlife managers and conservationists are thwarted by a singular challenge: Most ungulate migrations have never been mapped in sufficient detail to guide effective conservation. Without a strategic and collaborative effort, many of the world's great migrations will continue to be truncated, severed, or lost in the coming decades. Fortunately, a combination of animal tracking datasets, historical records, and local and Indigenous knowledge can form the basis for a global atlas of migrations, designed to support conservation action and policy at local, national, and international levels.

Summary Predicting the spatial pattern of disease risk in wild animal populations is important for implementing effective control programmes. We developed a risk model predicting the probability that a deer harvested in a wild population was chronic wasting disease positive (CWD+) and evaluated the importance of landscape connectivity based on deer movements. We quantified landscape connectivity from deer ‘resistance’ to move across the landscape similar to the flow of electrical current across a hypothetical electronic circuit. Resistance values to deer movement were derived as the inverse of step selection function values constructed using movement data from GPS-collared deer. The top CWD risk model indicated risk increased over time was higher among mule deer Odocoileus hemionus than white-tailed deer Odocoileus virginianus, males than females, and was greater in areas with high stream density and abundant agriculture. A metric of connectivity derived from mule deer movements outperformed models including Euclidean distance, with high connectivity being associated with high CWD risk. The CWD risk model was a good predictor of CWD occurrence among an independent set of surveillance data collected in subsequent years. Synthesis and applications. We found that landscape connectivity was a major contributor to the spatial pattern of chronic wasting disease (CWD) risk on a heterogeneous landscape. For this reason, future disease surveillance programmes and models of disease spread should consider landscape connectivity. In the aspen parkland ecosystem, we recommend managers focus surveillance and control efforts along river valleys surrounded by agriculture where mule deer abound, because of the high risk of CWD infection.

Identifying behavioral mechanisms that underlie observed movement patterns is difficult when animals employ sophisticated cognitive‐based strategies. Such strategies may arise when timing of return visits is important, for instance to allow for resource renewal or territorial patrolling. We fitted spatially explicit random‐walk models to GPS movement data of six wolves (Canis lupus; Linnaeus, 1758) from Alberta, Canada to investigate the importance of the following: (1) territorial surveillance likely related to renewal of scent marks along territorial edges, to reduce intraspecific risk among packs, and (2) delay in return to recently hunted areas, which may be related to anti‐predator responses of prey under varying prey densities. The movement models incorporated the spatiotemporal variable “time since last visit,” which acts as a wolf's memory index of its travel history and is integrated into the movement decision along with its position in relation to territory boundaries and information on local prey densities. We used a model selection framework to test hypotheses about the combined importance of these variables in wolf movement strategies. Time‐dependent movement for territory surveillance was supported by all wolf movement tracks. Wolves generally avoided territory edges, but this avoidance was reduced as time since last visit increased. Time‐dependent prey management was weak except in one wolf. This wolf selected locations with longer time since last visit and lower prey density, which led to a longer delay in revisiting high prey density sites. Our study shows that we can use spatially explicit random walks to identify behavioral strategies that merge environmental information and explicit spatiotemporal information on past movements (i.e., “when” and “where”) to make movement decisions. The approach allows us to better understand cognition‐based movement in relation to dynamic environments and resources.

The decline in Mountain caribou in BC over the past decades has resulted in extensive basic and applied research to guide caribou management by understanding the proximate and ultimate causes of the decline. At the top of the list is high predation rates brought about by human alteration of habitat and the subsequent alteration of predator-prey dynamics. We reviewed population-based management experiments undertaken in BC to recover caribou populations. These included primary prey (moose) reduction, lethal predator control, maternal penning, translocations, and supplemental feeding. Moose reduction by liberalized harvests has led to wolf population reduction and stabilization of treated caribou herds. Translocations have had limited success and finding source populations for future attempts will be a challenge. Maternity pens are producing promising results but their efficacy is strongest in relatively small populations and best results appear to occur when combined with predator control in areas surrounding the pens. Predator control experiments have just begun and results are forthcoming. Overall, no single population-based management tool has increased caribou populations. It is recommended that multiple levers need to be applied in combination on an experimental basis going forward.

Where carnivore species exist at low densities, are cryptic, and inhabit forested habitats where detection is low, survey approaches commonly rely on observation of tracks. Recent advances in probability sampling for aerial surveys of track networks in snow show promise for improving density estimates, but they are not applicable when continuously following a track network is not possible. Occupancy–abundance modeling is an alternative survey approach for wide-ranging carnivores, but past models may not be appropriate when using tracks because tracks of one individual or group of individuals may extend across several survey units. We derived an occupancy–abundance relationship by simulating the intersection of wolf (Canis lupus) travel paths and survey grid cells for a range of wolf-pack densities. Wolf movement paths were simulated using a habitat-biased, correlated random walk movement model using step lengths and turning angles of 17 Global Positioning System (GPS)-collared wolves in west-central Alberta, Canada. We estimated occupancy levels for a range of pack densities found in North America and found that pack density was linearly related to the proportion of occupied survey units. Concurrent movement paths of 5 GPS-collared wolf packs were used to evaluate the model predictions. While the model overestimated the number of packs by 33%, the difference translated into only 13 wolves across the study area. We discuss improvements for continued development of occupancy surveys as a potential method to determine carnivore abundance where other approaches are not feasible. © 2012 The Wildlife Society.

The 1988 Yellowstone fires were among the first in what has proven to be an upsurge in large severe fires in the western USA during the past 20 years. At the time of the fires, little was known about the impacts of such a large severe disturbance because scientists had had few previous opportunities to study such an event. Ecologists predicted short- and long-term effects of the 1988 fires on vegetation, biogeochemistry, primary productivity, wildlife, and aquatic ecosystems based on scientific understanding of the time. Twenty-plus years of subsequent study allow these early predictions to be evaluated. Most of the original predictions were at least partially supported, but some predictions were refuted, others nuanced, and a few postfire phenomena were entirely unexpected. Post-1988 Yellowstone studies catalyzed advances in ecology focused on the importance of spatial and temporal heterogeneity, contingent influences, and multiple interacting drivers. Post-1988 research in Yellowstone also has changed public perceptions of fire as an ecological process and attitudes towards fire management. Looking ahead to projected climate change and more frequent large fires, the well-documented ecological responses to the 1988 Yellowstone fires provide a foundation for detecting and evaluating potential changes in fire regimes of temperate mountainous regions.

The forage intake rate of grazing ungulates is limited either by the rate at which they encounter food items, or the rate at which food items are handled. Whether an ungulate is encounter- or handling-limited influences spatial and temporal depletion of forage, daily time budgets, and ultimately animal condition. Previously, vegetation abundance has been used as a surrogate for an ungulate's encounter rate with food items and related to observed bite rate to determine whether intake rate is encounter- or handling-limited. In temperate climates snow accumulation during winter limits access to vegetation by forcing animals to wade and paw through snow to consume underlying vegetation, increasing the amount of time required to encounter a food item. As a result, an ungulate may be handling-limited when foraging in a high biomass system under snow-free conditions, but becomes encounter-limited when snow accumulates. We derived a model that provides a frame work for estimating the rate at which a grazing ungulate encounters vegetation by considering foraging velocity, vegetation biomass and the time required to paw away snow when present. We then used data from focal observations of 36 wild elk Cervus canadensis wintering on a montane grassland in the Canadian Rockies of Alberta, Canada, to apply our model and estimate encounter rate over a range of vegetation abundance and snow conditions. Using AICc in a model selection approach we found that an asymptotic regression model of observed bite rate as a function of estimated encounter rate provided a better fit than similar models using only vegetation abundance as the explanatory variable. An asymptotic model suggests elk were handling-limited in the absence of snow, but became encounter-limited when snow accumulated. Our results demonstrate the importance of considering the influence of factors other than vegetation abundance on the intake rate of grazing ungulates.

Trade-offs between predation risk and forage fundamentally drive resource selection by animals. Among migratory ungulates, trade-offs can occur at large spatial scales through migration, which allows an "escape" from predation, but trade-offs can also occur at finer spatial scales. Previous authors suggest that ungulates will avoid predation risk at the largest scale, although few studies have examined multi-scale trade-offs to test for the relative benefits of risk avoidance across scales. Building on previously developed spatial models of forage and wolf predation risk, we tested for trade-offs at the broad landscape scale and at a finer, within-home-range scale for migratory and non-migratory resident elk (Cervus elaphus) during summer in the Canadian Rockies in Banff National Park (BNP) and adjacent Alberta, Canada. Migration reduced exposure to wolf predation risk by 70% relative to residents at the landscape scale; at the fine scale, migrants used areas that were, on average, 6% higher in forage digestibility. In contrast, by forgoing migration, resident elk were exposed to higher predation risk, but they reduced predation risk at fine scales to only 15% higher than migrants by using areas close to human activity, which wolves avoided. Thus, residents paid for trying to avoid predation risk with lower forage quality. Residents may have been able to compensate, however, by using areas of abundant forage close to human activity where they may have been able to forage more selectively while avoiding predation risk. Human activity effectively decoupled the positive correlation between high forage quality and wolf predation, providing an effective alternate strategy for residents, similar to recent findings in other systems. Although ungulates appear capable of balancing risk and forage at different spatial scales, risk avoidance at large landscape scales may be more effective in the absence of human-caused refugia from predation.

Most studies of habitat selection by large herbivores focus on the resource availability and interactions with other species, but neglect the importance of an animal being familiar with an area due to past use. Yet, studies of the establishment and retention of territories, home ranges, birth sites, and feeding site choices in experimental settings have shown the importance of spatial familiarity at these scales. We used GPS locations of translocated wapiti Cervus elaphus, resource selection functions (RSF), and time-to-return to examine whether previous site use was important for selection of sites by wapiti in west-central Alberta. To construct RSFs, we used logistic regression that included spatial familiarity (presence of a previous GPS location within a 50-m radius) as well as estimates of herbaceous and shrub biomass, elevation, aspect, slope, and predation risk to wapiti from wolf predation, as dependent variables. We found that previous use had a strong positive relationship with subsequent site use, indicating that wapiti were not avoiding previously visited locations, as would be expected if memory of forage depletion (which we did not measure) determined response to familiar locations. Revisited sites were of higher quality, i.e. had more moderate terrain, higher forage, and lower predation risk, than sites that were not revisited, indicating that the selection of familiar locations was likely not the result of avoidance of unfamiliar locations. Finally, animals demonstrated preference for familiar locations that it had visited most recently, indicating that memory (which would decline with time) of higher site quality, rather than high quality alone, influenced selection for familiar locations. We conclude that spatial familiarity is important not only for large scale processes such as selection of home range and territory, but for smaller scale habitat selection and foraging as well.

Summary 1. The ecological footprint of a road may extend for several kilometres with overlapping effects from neighbouring roads causing a nonlinear accumulation of road effects in the landscape. Availability of preferred habitat, spatial dependencies between roads and habitat types, and fidelity to traditionally used areas further confound our ability to predict population-level responses of animals to growing road networks. 2. To isolate these effects, we developed an individually based movement model using elk Cervus elaphus L. as a model system. Empirically derived movement rules redistributed elk under different amounts of preferred habitat (clearcuts), road densities, and road development schemes. We tracked potential mortality risk (given time spent near roads) and emigration rates (given declining accessibility of foraging habitat). 3. Design of the road network accounted for up to 30‐55% difference in mortality risk and emigration rates, with the largest differences occurring at intermediate road densities (1‐1·5 km km ‐2 ) when road effects began to saturate the landscape. Maintaining roads in association with clearcuts caused a decline in habitat accessibility equivalent to replacing 50‐75% of these foraging patches with conifer forest. A nine-fold difference in potential emigration was observed after varying elk tolerance for declining habitat accessibility despite holding local movement biases constant. 4. Elk responses to growing road networks were non-linear, exposing thresholds for road density that were reflected in the home range occupancy patterns of a large sample of elk in the region. 5. Synthesis and applications . Our approach provides a means of scaling-up complex movement decisions to population-level redistribution, separating the confounding effects of landscape context from road effects, and exposing thresholds in connectivity and mortality risks for wildlife caused by infrastructure growth. Our model indicated that road densities ≤ 0·5 km km ‐2 yielded the highest probability of elk occurrence where elk were hunted (and sensitive to roads), but disassociating roads from foraging habitats or managing human access to roads may maintain effective elk habitat at substantially higher road densities.

Accurate estimates of kill rates remain a key limitation to addressing many predator–prey questions. Past approaches for identifying kill sites of large predators, such as wolves (Canis lupus), have been limited primarily to areas with abundant winter snowfall and have required intensive ground-tracking or aerial monitoring. More recently, attempts have been made to identify clusters of locations obtained using Global Positioning System (GPS) collars on predators to identify kill sites. However, because decision rules used in determining clusters have not been consistent across studies, results are not necessarily comparable. We illustrate a space–time clustering approach to statistically define clusters of wolf GPS locations that might be wolf kill sites, and we then use binary and multinomial logistic regression to model the probability of a cluster being a non–kill site, kill site of small-bodied prey species, or kill site of a large-bodied prey species. We evaluated our approach using field v...

Global positioning system (GPS) collars are changing the face of wildlife research, yet they still possess biases such as habitat-induced fix-rate bias, which is a serious concern for habitat selection studies. We studied GPS bias in the Central Canadian Rockies, a critical area for wildlife conservation, to provide a statistical approach to correct GPS habitat bias for habitat selection studies using GPS collars. To model GPS habitat bias we deployed 11 different collars from 3 brands of GPS collars (Advanced Telemetry Systems [ATS], Asanti, MN; LOTEK Engineering Ltd., Newmarket, ON, Canada; and Televilt, Lindesberg, Sweden) in a random-stratified design at 86 sites across habitat and topographic conditions. We modeled the probability of obtaining a successful location, PFIX, as a function of habitat, topography, and collar brand using mixed-effects logistic regression in an information theoretic approach. For LOTEK collars, we also investigated the effect of 8 and 12 GPS channels on fix rate. T...

To maximize success, reintroduction programs generally select predator-free release areas having high habitat quality. Past studies provide little insight into recovery efforts where multiple, potentially novel, mortality hazards occur. The ability of translocated animals to cope with novel environments can be affected by both pre- and postrelease experiences with habitat and mortality risks. We experimentally released elk (Cervus elaphus) having different background experiences into an area where predators and hunters were prevalent and habitat quality varied. Using a competing risks approach, we predicted the postrelease survival of individuals and their fidelity to release areas as a function of animal source and postrelease encounters with forage resources and areas used by wolves (Canis lupus) or humans. Mortality patterns were consistent with prerelease exposure to mortality risks but not habitat differences among source areas. Wolf predation, poaching, and legal Native hunting were equival...

There is growing concern that populations of migratory ungulates are declining globally. Causes of declines in migratory behavior can be direct (i.e., differential harvest of migrants) or indirect (i.e., habitat fragmentation or land-use changes). Elk (Cervus elaphus) are an important big game species in North America whose migratory behavior is changing in some montane ecosystems. We evaluated evidence and hypotheses for changes in migratory behavior and population decline in one of Canada's largest elk populations, the Ya Ha Tinda. We compared the ratio of migrant to resident elk (M:R) in the population and seasonal spatial distributions obtained from 22 winter and 13 summer helicopter surveys between 1972 and 2005. Timing of migration and the summer distribution for a sample of radiocollared elk also was compared for 1977–1980 (early period) and 2001–2004 (recent). The population M:R ratio decreased from 12.4 (SD = 3.22) in the early period to 3.0 (SD = 1.63). The decrease was greater than expected based on population change. Declines in M:R also mirrored behavior of radiocollared elk. More than 49% of radiocollared elk we monitored resided near the winter range year-round by 2001–2004, and migrants were spending less time on summer ranges. We found winter range enhancements, access to hay fed to wintering horses, recolonization by gray wolves (Canis lupus), and management relocations of elk were most consistent with observed elk population growth (adjusted for harvest and removals) and the change in migratory behavior. However, we could not isolate the effects of specific factors in time-series population modeling. We believe directly relating migrant and resident demography to habitat and mortality factors will be required to understand the mechanisms affecting migratory behavior in this and other montane elk herds.

Prey species are thought to select habitats to obtain necessary resources while also avoiding predation. We examined whether habitat selection by elk (Cervus elaphus) changed following the reintroduction of wolves (Canis lupus) into Yellowstone National Park in 1995. Using conditional fixed-effects logistic regression to build habitat-selection models, we compared seasonal habitat selection by elk based on weekly elk radiolocations taken in 1985–1990 (without wolves) and 2000–2002 (with wolves). Fire-related habitat changes and climate likely interacted with wolf avoidance in shaping habitat selection by elk. In summer, when wolf activity was centered around dens and rendezvous sites, elk apparently avoided wolves by selecting higher elevations, less open habitat, more burned forest, and, in areas of high wolf density, steeper slopes than they had before wolf reintroduction. In winter, elk did not spatially separate themselves from wolves. Compared to the pre-wolf period, elk selected more open h...

Animals may respond to spatial and temporal heterogeneity by altering their movement patterns. The time an animal spends in an area of a given size is termed ȁ8first-passage timeȁ9 and can be used to identify the scales at which different movement processes occur. Using first-passage time and 2-h observations, we identified nested spatial scales representing three movement behaviours for elk (Cervus elaphus) – inactive/resting (moves

Native deciduous woodlands comprise

A Landsat Thematic Mapper (TM) based digital land cover map has been created for the state of Wyoming, USA, at moderate spatial (l-km2 minimum mapping unit) and high typal (41 land cover types) resolution as part of the Wyoming Gap Analysis Program (WGAP). This map presents opportunities for regional characterization of land cover, especially vegetation, and for examination of ecological phenomena that manifest themselves over large areas. Using the digital land cover data, we describe Wyoming vegetation and examine positions of three prominent physiognomic transitions in Wyoming: the elevation of upper and lower treeline, and the position of the biogeographic boundary between shruband grass-dominated vegetation. By area, the three leading land cover types in Wyoming are Artemisia tridentata ssp. wyomingensis sagebrush (33.4 %), mixed grass prairie (17.5 %) and Pinus contorta forest (6.5 %). Average upper-treeline elevation in Wyoming is 2947 m, and decreases with increasing latitude at an average rate of about 0.5 m/km, less than the rate of about 0.9 m/km reported by Peet (1978) for a gradient from Mexico to Canada. Lower-treeline occurs at an average elevation of 2241 m, and decreases with increasing latitude and with southerly aspect. In Wyoming, shrub-dominated communities are more likely to occur than grass-dominated communities as summer precipitation decreases below 282 mm. All of these relationships are subtle, and it appears that for particular areas, local factors are more important than regional climatic trends in explaining the position of phytogeographic boundaries.

Traditional methods for measurement of vegetative biomass can be time-consuming and labor­intensive, especially across large areas. Yet such estimates are necessary to investigate the effects of large scale disturbances on ecosystem components and processes. One alternative to traditional methods for monitoring rangeland vegetation is to use satellite imagery. Because foliage of plants differentially absorbs and reflects energy within the electromagnetic spectrum, remote sensing of spectral data can be used to quantify the amount of vegetative biomass present in an area (Tucker and Sellers 1986). In 1987 we found that Landsat Multispectral Scanner (MSS) imagery could be used to quantify green herbaceous phytomass (GHP) on ungulate summer range in the northeastern portion of Yellowstone National Park. Estimates of GHP in the study area were well within values reported for the habitat types sampled (Mueggler and Steward 1980). Annual variation in GHP was related to winter snow accumulation probably due to the timing of snow melt (Merrill et al. 1988). Additionally, we found that GHP explained a significant amount of the variation in the per capita growth rate of elk and bison populations from 1972 to 1987 (Merrill and Boyce 1991). The extensive fires that occurred in the Park in the summer of 1988 provided an opportunity to determine whether remote sensing could be used to monitor grassland vegetation recovery in the Park and to explore the effects of the 1988 fires on ungulate populations using models we developed in 1987. Previous studies have used Landsat imagery to monitor succession of seral stages after fire in pine (Jakubauska et al. 1990), but no studies to our knowledge have used this approach to quantify herbaceous recovery in grasslands.

The effects of ungulate grazing on the Northern winter range of Yellowstone National Park has recently received considerable attention. Early interest in this topic centered around the question to cull or not to cull elk in the Park. However, as the concepts of "maintaining ecological processes" (Houston 1982) and "ecosystem management" (Keiter 1991) have gained acceptance in Park management, understanding the dynamics and interactions of a broader array of herbivores inhabiting the Park will become increasingly important. In 1990, we studied the responses of Idaho fescue (Festuca idahoensis) and bluebunch wheatgrass (Agropyron spicatum) and their associated nematode communities to ungulate herbivory.

Management of elk on the northern winter range of Yellowstone National Park has remained a controversial subject through most of this century (Singer 1989). Until 1968 elk were artificially controlled because it was believed that ranching outside the park excluded elk from winter ranges resulting in unnaturally high populations in the Park and uncontrolled elk numbers would result in overgrazing and ecosystem degradation. However, in 1968 elk reductions were terminated and by 1971 a hypothesis of natural regulation was formulated by Park biologists (Singer 1989). The natural regulation hypothesis asserts that the Yellowstone area used by elk is an ecologically complete habitat (all required components of the habitat are present) and that density dependant factors will limit population growth of elk without major range degradation.

White-tailed (Odocoileus virginianus) and mule deer (0. hemionis) currently use Devils Tower National Monument and adjacent private agricultural lands year round or migrate from the Monument to other areas. In 1989, a game fence was constructed on the west and north borders of the Monument. Enclosure of the Monument by additional fencing could alter habitat use of deer substantially and create many of the problems associated with island reserves. National Park Service management policy directs the Monument to predict changes in the natural resources under its stewardship. Because current deer use of the Monument is not well documented, the Department of Zoology and Physiology and the Wyoming Cooperative Fish and Wildlife Research Unit, in cooperation with the Devils Tower National Monument, initiated a study in June 1990 to document current population numbers and habitat ecology of white-tailed and mule deer on the Monument as a baseline for monitoring long-term changes in the deer herd.

Currently, white-tailed (Odocoileus virginianus) and mule deer (0. hemionus) use Devils Tower National Monument and adjacent private agricultural lands year round or migrate from the Monument to other areas. Construction of a game proof fence by adjoining landowners threatens to enclose Devils Tower National Monument. If this occurs, deer use of the Monument may be substantially altered and long­term management of the population may be faced with many of the problems associated with island reserves. National Park Service management policy charges the Monument to detect or predict changes in the natural resources under its stewardship. However, current deer use of the Monument is not well documented so that a baseline for monitoring long term changes is lacking. The University of Wyoming Department of Zoology and Physiology and the Wyoming Cooperative Fish and Wildlife Research Unit, in cooperation with the University of Wyoming National Park Service Research Center and Devils Tower National Monument, initiated a study in June 1990 to document the population and habitat ecology of white­tailed and mule deer on Devils Tower National Monument. Objectives of the study during this reporting period were to: 1. radio-collar a representative sample of the adult female population of deer 2. radio-locate adult does to identify daily and seasonal habitat use and movement patterns 3. determine seasonal deer densities on the Monument

Green herbaceous phytomass was measured in August 1987 in grassland and sagebrush-grassland communities of Yellowstone National Park and related to August 1987 Landsat MSS data. A linear model using MSS band 7 and the ratio of MSS bands 6 to 4 accounted for 63% of the variance in green herbaceous phytomass on ground-truth plots (n = 25). Error in estimates of green herbaceous phytomass was influenced by the relative amount of bare ground and the proportion of green to green plus dead herbaceous vegetation present at a site. The model was used to predict average green herbaceous phytomass in grassland and sagebrush-grassland communities across a 600 km2 portion of ungulate summer range in Yellowstone National Park for 11 years during 1972-1987 using additional Landsat MSS imagery. Green herbaceous phytomass declined seasonally from late July to early September. Annual deviations in green herbaceous phytomass from the 11-year average, corrected for date of satellite overpass, were not significantly related to precipitation or temperatures during the growing season but were related quadratically to December-March precipitation. Below-average green herbaceous phytomass in years of low and Funding and data were provided by the National Park Service and the University of Wyoming-National Park Service Research Center under Contract UW-NPS # 532754. Authors acknowledge the assistance of Don Despain, Francis Singer, and John Varley of Yellowstone National Park. Tammy Willette, Daryl Lutz, and Brad Sauer provided assistance in the field. Dave Sturges of the Rocky Mountain Forest and Range Experiment Station, Laramie, Wyo., provided the capacitance meter. Drs. Paul Tueller, Steven Buskirk, Nancy Stanton, and 2 anonymous reviewers provided helpful comments on the manuscript. high winter precipitation may be related to the effects of snow accumulation and melt on phenological development (green wave) of plants across the summer range. Models based on MSS spectral data can provide useful descriptions of broadscale patterns of plant biomass in Yellowstone National Park but may not suffice when precise estimates are required. Climatic influences on plant phenology may confound the interpretation of results when spectral models are used to compare vegetation yield of forage availability among years.

We are adapting the spatially explicit, process-oriented model Savanna developed by M. B. Coughenour to Devils Tower National Monument (DTNM). The model will be used to describe the woodland-deer dynamics within a short time-frame (< 30 years) under several management scenarios. We use data on weather, vegetation standing crops, deer distributions and population information collected during 1991-1992 as initial conditions to the model.

Summer range is not thought to be limiting to elk because abundant, high quality forage is available whereas a shortage of forage usually exists on elk winter ranges. Nevertheless, summer nutrition and fat reserves acquired on summer ranges influence growth, survival and reproduction of ungulates (Klein 1965, Verme 1963, 1965, Julander et al. 1961). The enormous area of summer range for the Northern Yellowstone elk herd renders detailed field surveys impractical. This study was initiated to evaluate the feasibility of using LANDSAT satellite imagery to (1) characterize vegetation communities on summer range from LANDSAT multispectral scanner (MSS) data and digitized vegetation maps of Yellowstone National Park, (2) predict plant production within grassland types and (3) correlate elk population characteristics with fluctuations in plant production and weather.

Resource selection functions (RSF) can be used to explore the role of scale in determining patterns of habitat use. We estimated RSFs for 93 radiocollared adult female elk (Cervus canadensis) with resource availability defined at four spatial scales and two seasons in Yellowstone National Park. Habitat selection differed markedly among scales and seasonal ranges. During winter elk moved to ranges at lower elevations where snow water equivalents were low and selected landscapes with a mix of forest and open vegetation at all spatial scales. Areas of high vegetation diversity were selected at large spatial scales during summer, whereas elk selected less diverse areas on winter range. During summer elk selected forests that burned 12-14 y earlier, but they used these burns less than expected by chance during winter. Habitat selection by elk occurred at multiple spatial scales; thus, we cannot prescribe a single scale as being best for modelling habitat use by elk. Instead, selection of an appropriate...

In 1988, we developed an algorithm to predict green herbaceous biomass in sagebrush grassland communities of elk summer range using Landsat multi-spectral scanner (MSS) data (Merrill et al. 1988). Our objectives during this contract period were (1) to improve this predictive model and (2) to use the model for predicting vegetation recovery on grasslands burned in 1988.

Trends in productivity and mineral content of herbaceous vegetation in Ponderosa pine and montane grassland over a 4-year period are reported. Dry matter production on burned areas was 1.4, 1.3, 2.2 and 1.6 times that on unburned sites in the four successive years following the fire. Annual forbs and annual grasses contributed 56% of total dry matter the first year following fire. Perennial forbs contributed 40, 75, 75, and 77% of dry matter on the burned sites in successive years following the fire, compared with 66% on the unburned site. Herbage mineral concentrations did not change appreciably following fire, although low values for nitrogen and potassium were apparent in the first year. Responses of herbaceous understories in Ponderosa pine

Buring at 10-15-year intervals has been recommended in the warm, grand fir (Abies grandis)-myrtle pachistima (Pachistima Lochsa River of northern Idaho (Leege 1979). Spring and autumn burning generally promote sprouting of most shrub species in this community and produce valuable browse (Leege and Hickey 1971, Wright 1978). Fire is also a valuable tool in shrub and timber management in the more xeric ponderosa pine (Pinus ponderosa)-common snowberry (Symphoricarpos albus) communities (Davis et al. 1980). Effects of fire on production and mineral content of shrubs in this community have not been documented.