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Habitat loss is often the ultimate cause of species endangerment and is also a leading factor inhibiting species recovery. For this reason, species‐at‐risk legislation, policies and plans typically focus on habitat conservation and restoration as mechanisms for recovery. To assess the effectiveness of these instruments in decelerating habitat loss, we evaluated spatiotemporal habitat changes for an iconic endangered species, woodland caribou (Rangifer tarandus caribou). We quantified changes in forest cover, a key proxy of caribou habitat, for all caribou subpopulations in Alberta and British Columbia, Canada. Despite efforts under federal and provincial recovery plans, and requirements listed under Canada's Species at Risk Act, caribou subpopulations lost twice as much habitat as they gained during a 12‐year period (2000–2012). Drivers of habitat loss varied by ecotype, with Boreal and Northern Mountain caribou affected most by forest fire and Southern Mountain caribou affected more by forest harvest. Our case study emphasizes critical gaps between recovery planning and habitat management actions, which are a core expectation under most species‐at‐risk legislation. Loss of caribou habitat from 2000 to 2018 has accelerated. Linear features within caribou ranges have also increased over time, particularly seismic lines within Boreal caribou ranges, and we estimated that only 5% of seismic lines have functionally regenerated. Our findings support the idea that short‐term recovery actions such as predator reductions and translocations will likely just delay caribou extinction in the absence of well‐considered habitat management. Given the magnitude of ongoing habitat change, it is clear that unless the cumulative impacts of land‐uses are effectively addressed through planning and management actions that consider anthropogenic and natural disturbances, we will fail to achieve self‐sustaining woodland caribou populations across much of North America.

Significance A replicated management experiment was conducted across >90,000 km2 to test recovery options for woodland caribou, a species that was functionally extirpated from the contiguous United States in March 2018. Recovery options were reductions of predators, reductions of overabundant prey, translocations, and creating fenced refuges from predators. Population growth was strongest where multiple recovery options were applied simultaneously. This adaptive management study was one of the largest predator-prey manipulations ever conducted and provided positive results for this endangered North American ungulate., Adaptive management is a powerful means of learning about complex ecosystems, but is rarely used for recovering endangered species. Here, we demonstrate how it can benefit woodland caribou, which became the first large mammal extirpated from the contiguous United States in recent history. The continental scale of forest alteration and extended time needed for forest recovery means that relying only on habitat protection and restoration will likely fail. Therefore, population management is also needed as an emergency measure to avoid further extirpation. Reductions of predators and overabundant prey, translocations, and creating safe havens have been applied in a design covering >90,000 km2. Combinations of treatments that increased multiple vital rates produced the highest population growth. Moreover, the degree of ecosystem alteration did not influence this pattern. By coordinating recovery involving scientists, governments, and First Nations, treatments were applied across vast scales to benefit this iconic species.

Ecological “big data” Human activities are rapidly altering the natural world. Nowhere is this more evident, perhaps, than in the Arctic, yet this region remains one of the most remote and difficult to study. Researchers have increasingly relied on animal tracking data in these regions to understand individual species' responses, but if we want to understand larger-scale change, we need to integrate our understanding across species. Davidson et al. introduce an open-source data archive that currently hosts more than 15 million location data points across 96 species and use it to show distinct climate change responses across species. Such ecological “big data” can lead to a wider understanding of change. Science , this issue p. 712

Habitat change is a major driver of species distribution and persistence, but there have been few recorded extinction events for terrestrial mammals across Canada. Currently, we are observing the decline, extirpation, and perhaps extinction of several evolutionarily significant units of woodland caribou ( Rangifer tarandus caribou ), an iconic and cultural keystone species. We used an extensive set of caribou locations (5 subpopulations, 102 animals, 270,808 GPS-collar locations) collected over 11 years within the Central Mountain Designatable Unit to develop species distribution models that quantified avoidance by caribou of anthropogenic and natural disturbance features. Those empirical relationships allowed us to measure the loss of habitat over a 22-year period and correlate habitat change with measured population decline. The disturbance responses for caribou were complex and varied by season and subpopulation. We modelled a zone of influence for roads (1.75 km), seismic and pipelines (2.5 km), oil and gas features (4.25 km), cutblocks (5.5 km), burns (8.0 km), and coal mines (3.0 km). When the distribution models for each subpopulation were applied to the respective seasonal ranges, we measured a maximum loss in high-quality habitat of 65.9%. The reduction in habitat was strongly correlated with the annual multiplicative growth rate of 5 subpopulations of caribou. At current rates of habitat loss and population decline, these caribou, a significant component of Canada’s biodiversity, are unlikely to persist. Although the factors leading to extinction are complex, the cumulative impacts of industrial development are a correlative if not causative factor.

Woodland caribou (Rangifer tarandus caribou) are a species of increasing conservation concern across North America. Throughout much of boreal Canada, human developments, including forestry and energy development, are now accepted causes of the decline in the number and distribution of caribou. One of the hypothesised mechanisms for the decline is altered predator–prey dynamics. We quantified the impacts of a variety of industrial activities on gray wolf (Canis lupus) and caribou interactions at a regional scale. We used animal locations collected with global positioning system collars and field data to examine how a range of industrial developments influenced the movements of wolves. We quantified the speed of wolf movements and the tortuosity of movement paths at two spatiotemporal scales across forested boreal and mountainous environments occupied by woodland caribou. Habitat and disturbance features better explained wolf movements during the weekly scale. In general, linear movements increased during winter, which paralleled past studies that suggested linear travel by wolves was associated with deep snow and the increased maintenance and patrol of territories. Wolves decreased movement rates but not sinuosity within close proximity to disturbance features, thus implying behaviours near such features were more closely associated with prey searching and hunting. Alternatively, wolves increased movement rates and linear travel through areas with high densities of linear and non-linear industrial features; this response suggested that wolves avoided spending time in high-risk areas associated with human activities. Results of this study further our understanding of wolf distribution and behaviour in habitats supporting populations of caribou within a matrix of industrial developments.

Across much of the range of woodland caribou (Rangifer tarandus caribou), predator–prey dynamics have changed as a result of large‐scale industrial development. Land clearing and associated early‐successional forests have resulted in a greater density and distribution of moose (Alces alces), deer (Odocoileus spp.), and their associated predators. This process of apparent competition has resulted in increased predation on woodland caribou. We employed a combination of field and statistical methods to better understand the distribution and interactions of wolves (Canis lupus) and caribou across a region with high levels of industrial development. We used count models to investigate the frequency of wolf occurrence relative to landcover types, disturbance features, and caribou habitat. As predicted, the co‐occurrence between caribou and wolves was rare. Similarly, the remains of caribou were identified at a small proportion of the sites where wolves killed large prey. Caribou occurred at low densities across the study area, and thus, wolves likely pursued other more abundant deer species. Encounters between wolves and caribou habitat was most likely to occur in the low‐elevation boreal forest and areas closer to and with higher densities of forestry cutblocks. Our results highlight the importance of understanding the spatial dynamics of multi‐species interactions when developing recovery strategies for threatened and endangered species.

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that historically occurred throughout the high snowfall regions of southeast British Columbia and the northwestern United States. The decline in caribou is thought to be due to apparent competition where increases inearly-seral conditionsstimulateanumerical responseinprimaryungulate preyandtheir predators and these incidentally kill an unsustainable number of caribou. Based on the known location of death of 207 radio collared animals, we tested hypotheses pertaining to relationships between landscape composition and predator-specific mortality of mountain caribou at 2 ecologically based spatial scales. Relative to landscape conditions within subpopulation boundaries (level 1) or within home ranges (level 2), caribou were at greater risk of predation at low elevations particularly within otherwise complex terrain (i.e., valleys) with more variation in overstory canopy closure and greater road densities. Caribou vulnerability to bears was also positively related to the variation in overstory age. Cougar predation was not related to roads or terrain complexity but occurred more often in landscapes with warmer aspects and greater proportions of stands of

Summary 1. Ecosystem restoration typically focuses on re-establishing native plant communities with the hope of restoring ecological processes over the long term. In contrast, endangered species management usually focuses on short-term actions that directly affect population numbers. Here, we present an intermediate approach. We develop an ecologically based population target for the overabundant herbivore, moose Alces alces, with the goal of restoring a predator–prey system and thus preventing the extinction of the endangered ungulate, woodland caribou Rangifer tarandus. 2. Forest harvesting is a major factor contributing to increases in the number of moose, which in turn increases predator populations. Caribou populations decline as a result of increased predation representing a form of apparent competition between moose and caribou. This presents a unique conservation challenge as recovery of caribou through forest restoration would take decades, while the alternative of directly reducing predator numbers is a short-term solution. A third option is to reduce moose numbers to also maintain predators at low numbers, but the question is to what density should moose be reduced? 3. We created a statistically based target for moose abundance under conditions without forest harvesting by developing a habitat-based population model for moose under current conditions. We then calculated the habitat quality in the same area but under simulated ‘pristine’ conditions. We also evaluated three measures of ecological carrying capacity to determine the reliability of using current moose abundance to back-calculate numbers for the pristine landscape. 4. Our analysis suggests an 81·6% (71·0–89·9%, 95% CI) reduction in moose habitat quality under pristine conditions. All three measures indicated that moose numbers in the current landscape were near carrying capacity, suggesting that the current abundance could be used to approximate numbers for the pristine landscape and thus be used as an ecological target. 5.Synthesis and applications. There are few experimental tests designed to alleviate predator-mediated apparent competition by reducing overabundant prey. Our target will now be used in an adaptive management framework to evaluate the success of this recovery option for caribou, and inform whether this approach can be applied to other systems involving species endangerment from the apparent competition mechanism.

We studied migration, birth rate and death rate of 59 grizzly bears Ursus arctos on a plateau (N = 29) with extensive forestry activities, and adjacent relatively undeveloped mountains (N = 30) during 1998–2003, to examine population parameters and/or limiting factors that might have contributed to a large difference in grizzly bear density between landscapes. Female bears in our low-density area (i.e. plateau) were heavier, in better condition, and more often accompanied by cubs than their mountain counterparts. Survival rates were comparable for adult bears but were significantly lower for subadult bears on the plateau. All deaths of bears which lived on the plateau for which cause of death was identified were human-caused as compared with one of three in the mountains. Plateau bear deaths were highest in fall coinciding with people hunting other species. Density-dependent factors appeared to be more important to mountain bear demographics, whereas bears on the plateau appeared to be limited by human-ca...

Animal locations collected by Global Positioning System (GPS) collars will represent a biased sample of the sites an animal used if some position fixes fail and if those missed locations do not occur randomly. Probability of a GPS receiver obtaining a position fix is known to decline as canopy cover increases, but the impact of forest canopy cover was insufficient to account for the low fix rates we observed for GPS collars on grizzly bears (Ursus arctos). We tested the hypothesis that GPS fix rates were related to the interaction between animal activity (active vs. resting) and canopy cover by evaluating the following predictions: 1) grizzly bear activity should follow a circadian pattern similar to the circadian fix-rate pattern, 2) grizzly bear use of canopy cover should follow a circadian pattern similar to the circadian fix rates, 3) grizzly bear activity should be related to canopy cover (i.e., bears should rest in areas with relatively high canopy covers and feed and move in relatively ope...

Much of applied and theoretical ecology is concerned with the interactions of habitat quality, animal distribution, and population abundance. We tested a technique that uses resource selection functions (RSF) to scale animal density to the relative probability of selecting a patch of habitat. Following an accurate survey of a reference block, the habitat-based density estimator can be used to predict population abundance for other areas with no or unreliable survey data. We parameterized and tested the technique using multiple years of radiotelemetry locations and survey data collected for woodland caribou across four landscape-level survey blocks. The habitat-based density estimator performed poorly. Predictions were no better than those of a simple area estimator and in some cases deviated from the observed by a factor of 10. We developed a simulation model to investigate factors that might influence prediction success. We experimentally manipulated population density, caribou distribution, ability of animals to track carrying capacity, and precision of the estimation equation. Our simulations suggested that interactions between population density, the size of the reference block, and the pattern of distribution can lead to large discrepancies between observed and predicted population numbers. Over- or undermatching patch carrying capacity and precision of the estimator can influence predictions, but the effect is much less extreme. Although there is some empirical and theoretical evidence to support a relationship between animal abundance and resource selection, our study suggests that a number of factors can seriously confound these relationships. Habitat-based density estimators might be effective where a stable, isolated population at equilibrium is used to generate predictions for areas with similar population parameters and ecological conditions.

The purpose of our study is to show how ecologists' interpretation of habitat selection by grizzly bears (Ursus arctos) is altered by the scale of observation and also how management questions would be best addressed using predetermined scales of analysis. Using resource selection functions (RSF) we examined how variation in the spatial extent of availability affected our interpretation of habitat selection by grizzly bears inhabiting mountain and plateau landscapes. We estimated separate models for females and males using three spatial extents: within the study area, within the home range, and within predetermined movement buffers. We employed two methods for evaluating the effects of scale on our RSF designs. First, we chose a priori six candidate models, estimated at each scale, and ranked them using Akaike Information Criteria. Using this method, results changed among scales for males but not for females. For female bears, models that included the full suite of covariates predicted habitat use best at each scale. For male bears that resided in the mountains, models based on forest successional stages ranked highest at the study-wide and home range extents, whereas models containing covariates based on terrain features ranked highest at the buffer extent. For male bears on the plateau, each scale estimated a different highest-ranked model. Second, we examined differences among model coefficients across the three scales for one candidate model. We found that both the magnitude and direction of coefficients were dependent upon the scale examined; results varied between landscapes, scales, and sexes. Greenness, reflecting lush green vegetation, was a strong predictor of the presence of female bears in both landscapes and males that resided in the mountains. Male bears on the plateau were the only animals to select areas that exposed them to a high risk of mortality by humans. Our results show that grizzly bear habitat selection is scale dependent. Further, the selection of resources can be dependent upon the availability of a particular vegetation type on the landscape. From a management perspective, decisions should be based on a hierarchical process of habitat selection, recognizing that selection patterns vary across scales.

Mountain caribou are an ecotype of woodland caribou (Rangifer tarandus caribou) that live in subalpine forests in south-eastern British Columbia, Canada, extending into northern Idaho and Washington, USA. These caribou are listed as Threatened in Canada, Endangered in the United States, and are the subject of recovery planning efforts in both countries. Many areas of mountain caribou winter habitat experience intensive use by recreational snowmobilers. During 4 surveys, we recorded caribou on all 4 census blocks with little or no snowmobile activity (x density = 0.41 caribou/km2), but during 3 of 4 years, we observed no caribou on the census block with intensive snowmobile activity. The year we observed caribou on the snowmobile block, most were using areas inaccessible to snowmobiles. We used a Resource Selection Function (RSF) based on radiotelemetry data for the area to compare habitat quality among the different census blocks. The absence of caribou from the intensive snowmobile area during ...

The Parsnip River area in British Columbia (BC), Canada, provides important habitat for grizzly bears (Ursus arctos). This area contains 2 adjacent topographic regions: (1) a relatively pristine portion of the Hart Ranges of the Canadian Rocky Mountains, and (2) a plateau on which timber harvests have occurred. Increasing human modification of both landscapes may affect the quality of grizzly bear habitat. Therefore, we examined denning behavior and den-site selection of grizzly bears in this area based on data from 61 grizzly bears radiocollared between 1997 and 2002 (34 plateau, 27 mountain bears). Adult females residing in the mountainous landscape arrived earlier to their denning areas (14 Oct versus 26 Oct), entered dens earlier (23 Oct versus 9 Nov), and emerged later (11 May versus 24 Apr) than plateau females, spending on average 36 days longer in their dens (200 days versus 164 days). Dens used in consecutive years by mountain females tended to be closer to one another (x = 2.4 km) than those of plateau females (x = 5.1 km). Dens in the mountains were excavations into sloping ground (74%), or natural caves (26%), using rocks as the primary stabilizing structure (47%). Resource selection functions (RSF) revealed that mountain grizzly bears selected dens in alpine habitats at mid-to-upper elevations. Plateau bears mainly excavated dens under the base of trees (90%), where roots stabilized material (80%). These dens primarily were located in older-aged forest stands ranging from 45–99 years (40%) or >100 years (50%); RSFs further revealed that grizzly bears on the plateau selected stands with tall trees. Plateau dens also were located away from roads, possibly because of less disturbance and because older trees were farther from roads.

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival.

We collected hair samples from bears and used microsatellite genotyping to identify individual bears on three study areas near the Canadian Rocky Mountains. We estimated density of grizzly bears Ursus arctos in eight different ecosystems across five study areas, including the reanalysis of two previously published data sets. We also estimated black bear U. americanus density for two ecosystems in one study area. Grizzly bear density was lowest in boreal and sub-boreal plateau areas, moderate in the Rocky Mountain east slopes and highest in the Rocky Mountain west slopes. Presumably these gross differences are related to ecosystem productivity. In the Rocky Mountain west slopes, grizzly bear density was lower in populations that were partially isolated from the continuous bear population to the north. Presumably, these differences have more to do with human impacts on habitat and survival than ecosystem productivity, because productivity in partially isolated areas was similar to productivity in adjacent continuous populations. We show that large differences in bear density occur down to the ecoregion scale; broader ecosystem classes such as Banci's (1991) grizzly bear zones, ecoprovinces or ecozones would include areas with major differences in density and are therefore too coarse a scale at which to predict grizzly bear density. There appears to be little movement across ecoregion boundaries further suggesting that this may be an appropriate scale at which to extrapolate density. Differences in density across finer-scale ecosystems are likely due to seasonal movements and not population level differences in density. Average bear movements were longer in less productive ecosystems. Female grizzly bears did not appear to leave their home ranges to fish for salmon Oncorhynchus spp., and extra-territorial movements by males appeared to be rare, in both ecosystems which supported spawning salmon.

Summary 1 Visualizing the distribution of rare or threatened species is necessary for effective implementation of conservation initiatives. Generalized linear models and geographical information systems (GIS) are now powerful tools for conservation planning, but issues of data availability, scale and model extrapolation complicate some applications. 2 Mountain caribou are an endangered ecotype of woodland caribou Rangifer tarandus caribou that occurs across central and southern British Columbia, Canada. Currently, conservation professionals use coarse small-scale maps of important habitats to manage forest harvesting and human access across the northern extent of mountain caribou range. These maps were produced before the advent of readily available digital spatial information and are based on expert opinion and limited empirical data. 3 With the purpose of refining existing maps, we used survey results, radio-telemetry locations and GIS data to construct resource selection functions (RSF) that quantified the habitat affinities and predicted the relative probability of occurrence of mountain caribou at two spatial scales. At the scale of the patch, the most parsimonious RSF model consisted of covariates for vegetation and aptly predicted the occurrence of caribou across low- to mid-elevation habitats, but performed poorly across steep alpine terrain. At the landscape scale, a model containing Gaussian terms for elevation and slope was effective at predicting the broader distribution of caribou. 4 We produced a map consisting of the product of the relative probabilities of the patch and landscape RSF. The final map represented the relative probability of occurrence of caribou in vegetative patches weighted by the relative probability of occurrence across the larger study area. We found strong agreement between current definitions of important caribou habitats developed from expert opinion and RSF-based maps generated from empirical data. 5 Synthesis and applications. Both expert opinion and RSF-based approaches offer unique advantages for conservation mapping. Interpretability of results, documentation and repeatability of methods and data, estimates of precision and costs should all be considered when evaluating a technique. We argue that for some species and geographical locations, RSF is a superior technique, but expert opinion should play a role in model development and interpretation.

Caribou (Rangifer tarandus caribou), wolves (Canis lupus), and moose (Alces alces) were radio-collared and monitored in two areas of southeastern British Columbia to determine predator–prey interactions. Throughout the year, wolves and moose used similar areas and habitats, and moose were the primary prey of wolves. In winter most caribou used high-elevation habitats and were spatially separated from wolves and moose living in valley bottoms. In summer, caribou, wolves, and moose at Quesnel Lake used similar areas and habitats, whereas in Wells Gray Park most caribou migrated to rugged, mountainous areas, which kept them spatially separated from wolves and moose. The Quesnel Lake caribou population had a high adult mortality rate (29%/year), wolf predation being the major cause. Calf survival to October was low (2.5/100 adult females) when wolves were present and uncontrolled in the area, but was significantly greater (39/100 adult females) when wolves were reduced or absent. The Quesnel Lake caribou population was found to be declining by about 25%/year, and wolf predation appeared to be the major limiting factor. Caribou in Wells Gray Park had a low adult mortality rate (8%/year) and comparatively high calf survival to October (37/100 adult females). The Wells Gray caribou population was found to be slowly increasing, apparently because its migratory behavior kept it separated from wolves and moose throughout the year, resulting in low wolf predation on the caribou.

In North America, caribou (Rangifer tarandus) experienced diversification in separate refugia before the last glacial maximum. Geographical isolation produced the barren-ground caribou (Rangifer tarandus groenlandicus) with its distinctive migratory habits, and the woodland caribou (Rangifer tarandus caribou), which has sedentary behaviour and is now in danger of extinction. Herein we report on the phylogenetics, population structure, and migratory habits of caribou in the Canadian Rockies, utilizing molecular and spatial data for 223 individuals. Mitochondrial DNA analyses show the occurrence of two highly diverged lineages; the Beringian-Eurasian and North American lineages, while microsatellite data reveal that present-day Rockies' caribou populations have resulted from interbreeding between these diverged lineages. An ice-free corridor at the end of the last glaciation likely allowed, for the first time, for barren-ground caribou to migrate from the North and overlap with woodland caribou expanding from the South. The lack of correlation between nuclear and mitochondrial data may indicate that different environmental forces, which might also include human-caused habitat loss and fragmentation, are currently reshaping the population structure of this postglacial hybrid swarm. Furthermore, spatial ecological data show evidence of pronounced migratory behaviour within the study area, and suggest that the probability of being migratory may be higher in individual caribou carrying a Beringian-Eurasian haplotype which is mainly associated with the barren-ground subspecies. Overall, our analyses reveal an intriguing example of postglacial mixing of diverged lineages. In a landscape that is changing due to climatic and human-mediated factors, an understanding of these dynamics, both past and present, is essential for management and conservation of these populations.

The abundance and geographic range of woodland caribou (Rangifer tarandus caribou) decreased in many areas of British Columbia during the 1900's. Recent studies have found that predation during the summer is the major cause of mortality and current population declines. Increased moose {Alecs alces) populations may be related to past and current caribou declines by sustaining greater numbers of wolves (Canis lupus). Mortality rates were greater in areas where caribou calved in forested habitats, in close proximity to predators and moose. Caribou populations which had calving sites in alpine areas, islands, and rugged mountains experienced lower mortality and were generally stable or increasing. A predator-induced population decline in one area appeared to stabilize at low caribou densities, suggesting that the wolf predation rate may be density dependent.

Wolf (Canis lupus) predation is a major limiting factor of many ungulate populations in North America. Predation by wolves can be density-dependent and regulate prey populations at low densities. In some situations, wolf predation can eliminate prey populations. In the past, large-scale wolf control programs, which exterminated or greatly reduced wolf populations, apparently resulted in increased ungulate populations. Recent, small-scale wolf control programs often increased survival rates of prey populations, but most of those programs were terminated before a prey population increase could be clearly demonstrated. It appears that if wolf control is to be used to maintain increased ungulate populations, the control must be ongoing due to the rapid recolonization and numerical response of wolves. Ongoing wolf control could potentially increase both prey and wolf numbers over the long term by preventing wolves from reducing their prey to low numbers. Although wolf control has the potential to increase prey (and possibly wolf) numbers, its use is severely limited by technical constraints and public opposition. Effective, ongoing wolf control programs are often technically and financially unfeasible. Wolf control programs encounter severe public opposition due to animal-rights concerns for the wolf and opposition to human manipulation of natural ecosystems.

Foraging behaviour of Stone's sheep (Ovis dalli stonei) was compared between different times of the year and between burned and unburned ranges. Seasonal habitat selection resulted in the sheep feeding on the ranges which provided the highest quality available forage. In winter, snow severely restricted the area that provided available forage. Sheep fed primarily on grasses, although forbs and browse were also important foods in the spring and summer. Plant species selected by the sheep in summer were not higher in protein or lower in acid detergent fiber than avoided species, but rather lacked the physical and chemical deterrents present in avoided plants. Intake rate (estimated from biting rate of ewes and foraging time) appeared to be independent of herbage quantity on spring ranges.

Species composition and herbage production were determined for different range types used by ungulates in northern British Columbia. In addition, the effect of N fertilization on alpine grasslands was measured. Fire-induced subalpine grasslands produced much more herbage than other range types. Graminoid production, but not forb production, was greater in wet growing seasons. Fertilization of alpine ranges with 17–35 kg N/ha did not increase the herbage production.

Etude menee de 1980 a 1983 dans le nord des Rocheuses, pres de la Toad River, Colombie Britannique. La qualite du fourrage dans les zones brulees n'est pas superieure a celle du fourrage des zones non brulees