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Stable isotope composition (δ13C and δ15N) of moose (Alces alces) and caribou (Rangifer tarandus) hair from the boreal forest of Jacques-Cartier Park and Cote-Nord (Quebec) and arctic tundra of Queen Maud Gulf and Southampton Island (Nunavut) was investigated as an indicator of dietary preferences and habitat use. Values of δ13Chair and δ15Nhair in moose were consistently lower compared to those of caribou. This is consistent with the depletion in 13C and 15N in the plants preferred by moose, essentially browse (shrub and tree leaves), compared to caribou forage, which included significant amounts of graminoids, lichen and fungi. The δ13Chair values of caribou differed between closed boreal forest and open-tundra ecosystems. This pattern followed that expected from the canopy effect observed in plant communities. Variation in δ15Nhair values of caribou was probably linked to the effect of different climatic conditions on plant communities. This study underlines the potential of isotopic analysis for studies on diet and habitat selection within a pure C3 plant environment. [ABSTRACT FROM AUTHOR]

The forest-dwelling ecotype of woodland caribou (Rangifer tarandus caribou) is vulnerable to predation, hunting, and disturbances due to anthropogenic activities. Its strategies of space and habitat use are oriented towards reducing the effects of these limiting factors. Caribou occupy large home ranges, undertake extensive movements, and avoid fragmented areas. They use various habitats, but especially mature and over-mature conifer stands with irregular structure, which are less suitable for other ungulates, wolves and black bears. In order to protect habitat for forest-dwelling caribou, we suggest an ecosystem approach based on the protection of large forested blocks, the concentration of forest harvesting in large management blocks, and the maintenance of habitat connectivity. This strategy focuses on short-term conservation of minimum caribou habitats in the protected blocks, a medium-term habitat recovery in the management blocks, the maintenance of forest activities, and facilitation of seasonal and dispersal movements. Within the management blocks, we recommend creation of an irregular forest structure similar to the pattern created by natural disturbances inherent to spruce-moss forests. These guidelines have been tested in Québec for the last few years and were well received by forest and wildlife agencies as well as the forest industry. [ABSTRACT FROM AUTHOR]

We documented how commercial logging influenced the spatial behaviorand nutritional ecology of northern white-tailed deer (Odocoileus virginianus). Using periodic browse surveys, we estimated the additional biomass of twigs available from felled trees to deer in the Pohenegamook wintering area (25 km2) at 55 kg/ha in a 43-ha cut conducted in 1995-1996 that aimed to favor conifers by removing overtopping deciduous trees. Over the entire winter, deer used 54% of the browse made available by the felling residues. The use of the cutover,estimated by pellet group census, was five times greater than the average recorded over the entire wintering area. Felled trees provided approximately 35% of the food intake of the animals that have used the cutover. Of 30 deer fitted with radio collars, the cutover attracted only those whose range neighbored the logging area (<2 km). In preference tests carried out in the winter of 1996-1997, deer showed no preference for twigs from newly cut trees over those from trees cut earlier in the winter, nor for twigs from treetops (browse made accessible during the logging operation) over twigs from saplings (browse usually accessible in winter). If commercial logging is conducted in winter as a means of providing emergency food during snowy winters to enhance deer survival, our results suggest that partial cutting may beineffective because felling residues were used only by deer found near the cutover and because of the difficulties of logging in deep snow. [ABSTRACT FROM AUTHOR]

1. Prey may trade off resource acquisition with mortality risk by using various habitat selection strategies. Empirical assessments have shown that the functional and numerical responses of predators to human disturbances are variable, yet spatial changes in predation risk by two predators have seldom been studied for prey occurring in human-modified landscapes. Using the boreal caribou Rangifer tarandus caribou - grey wolf Canis lupus - black bear Ursus americanus system in eastern Canada, we investigated whether responses of prey towards one predator could concomitantly increase risk of predation from another predator exhibiting a different foraging tactic. 2. We investigated trade-offs made by solitary caribou females and mothers accompanied by their calf during the period of highest calf vulnerability and compared the behaviour of mothers that would eventually lose their calf to predation to that of mothers whose calf survived until the following year. We modelled habitat selection using different metrics of forage based on field measurements and digital maps and developed empirical models of predation risk and prey behaviour using GPS data collected on both predators and prey. 3. Mothers accompanied by their calf seemed to compromise foraging opportunities for safety, as opposed to solitary females who showed no particular avoidance of areas used by predators. Although caribou mothers adopted selection strategies that could have protected their offspring from wolves, females that eventually lost their calf to predation selected for vegetative associations that were favourable to bears. 4. Synthesis and applications. We determined that mothers that most strongly avoided suitable wolf habitat were also those that most strongly selected suitable bear habitat, suggesting that by using antipredator strategies aimed at reducing predation risk from wolves, caribou exposed their offspring to increased predation risk from bears. This result is of paramount conservation value as bears were responsible for 94% of caribou calf kills in this system. In the short term, conservation efforts for boreal caribou may benefit from the management of bear populations by means of liberal hunting regulations or predator control. In the long term, however, these actions should be used in conjunction with the protection of potential calving areas away from cutblocks and roads. [ABSTRACT FROM AUTHOR]

Fifty-seven Moose (Alces alces) were monitored by telemetry in eastern Quebec between 1989 and 1991. The 1034 telemetry locations allowedcharacterization of the movement pattern of juvenile Moose and adults of both sexes on a seasonal and yearly basis i.e., summer, fall, winter). The population was characterised by restricted daily movements, large home ranges, and non-migratory animals. The minimum daily movements varied considerably between individuals but were estimated at 0.22 km/day. Summer minimum daily distances differed significantly (P< 0.01) between juveniles (0.34 km/d), adult females (0.14 km/d) andadult males (0.20 km/d). Minimum daily movements were more importantin fall (0.28 km/d) than in winter (0.12 km/d; P < 0.05). In summer,minimum daily movements were intermediate (0.21 km/d) compared to fall and winter values. The total home range size, as estimated with the minimum convex polygon, was 112 km2 and 131 km2 respectively for adult females and males and 66 km2 forjuveniles. On an annual basis, home range sizes did not differ (P > 0.05) between juveniles and adults, nor between adult males and females. For females, the smallest home ranges (19 km2 ) were noted in fall. The space utilisation patterns of Moose in eastern Quebec could be influenced by the low population densities, the absence of efficient predators, the low incidence of lakes, and by the skewed sex-ratio towards females induced by heavy hunting. [ABSTRACT FROM AUTHOR]

Spruce Grouse (Falcipennis canadensis) were introduced on Anticosti Island in 1985 and 1986. This introduction provided an opportunity tostudy habitat utilization where low population density did not affect habitat selection. In order to study habitat utilization, eight females and six males were equipped with radio-transmitters. These birdswere located on average once every 1.5 days between 18 May and 9 July 1986 for a total of 91 locations for the females and 103 for the males. Overall, sites used by Spruce Grouse were characterized by a dense shrub layer, particularly during nesting and brooding periods whencompared with control sites. Males used a broader range of habitats when compared with females. The utilization of an open habitat duringthe breeding period compared to the other periods and may be relatedto the greater efficiency of the breeding display in such habitat. After the breeding period, males utilized sites having a denser tree and shrub layers, possibly to reduce predation risk as their flying capacity is reduced during molting. Females nest in sites having similar characteristics to those used by males during this period, seeking sites that can potentially reduce predation risk. Sites utilized during the first week of the brooding period were comparable to those used during the nesting period. However, during the second part of the brooding period, females moved to older stands characterized by lower tree and shrub densities. In the first year following introduction, nesting success was 62.5 percent. Results obtained in this study supported previous findings obtained in other regions and suggested that this introduction will be a success. [ABSTRACT FROM AUTHOR]

A species may modify its relative habitat use with changing availability, generating functional responses in habitat selection. Functional responses in habitat selection are expected to occur when animals experience trade-offs influencing their habitat selection, but only a few studies to date have explicitly linked functional responses to the underlying trade-offs faced by the animals. We used data from 39 female moose fitted with GPS telemetry collars in two nearby study areas in Canada to investigate if moose (1) were faced with a food/cover trade-off in habitat selection, as typically acknowledged in the literature, and (2) showed a functional response in their use of food/cover-rich habitats. We also examined how habitat selection patterns varied seasonally, and between study areas. The occurrence of functional responses varied strongly between study areas, and could not always be related to a measurable food/cover trade-off. Functional responses were observed more often in the study area where the environmental conditions were more severe (colder temperatures, higher precipitations, and lower food availability). Selection coefficients were also less variable among individuals in that study area, suggesting that severe environmental conditions may constrain individuals to a few selection tactics and promote the development of functional responses. Moose reacted to the availability of different habitat types in different seasons, reflecting the changing trade-offs faced by the animals. We found considerable behavioral differences between individuals from two adjacent study areas, and therefore recommend caution when extrapolating habitat selection results. We advocate for the wider use of functional responses to identify critical habitats for a species from a management or conservation perspective. [ABSTRACT FROM AUTHOR]

The impact of anthropogenic disturbance on the fitness of prey should depend on the relative effect of human activities on different trophic levels. This verification remains rare, however, especially for large animals. We investigated the functional link between habitat selection of female caribou (Rangifer tarandus) and the survival of their calves, a fitness correlate. This top-down controlled population of the threatened forest-dwelling caribou inhabits a managed forest occupied by wolves (Canis lupus) and black bears (Ursus americanus). Sixty-one per cent of calves died from bear predation within two months following their birth. Variation in habitat selection tactics among mothers resulted in different mortality risks for their calves. When calves occupied areas with few deciduous trees, they were more likely to die from predation if the local road density was high. Although caribou are typically associated with pristine forests, females selected recent cutovers without negative impact on calf survival. This selection became detrimental, however, as regeneration took place in harvested stands owing to increased bear predation. We demonstrate that human disturbance has asymmetrical consequences on the trophic levels of a food web involving multiple large mammals, which resulted in habitat selection tactics with a greater short-term fitness payoff and, therefore, with higher evolutionary opportunity. [ABSTRACT FROM AUTHOR]

The study of habitat selection usually compares assessments of habitat use to habitat availability. To investigate habitat selection of large mammals today, researchers must choose between a few very expensive Global Positioning System (GPS) telemetry collars that can provide many locations and several inexpensive very high frequency telemetry collars that will provide few numbers of locations (unless substantial resources are spent in the field). We investigated the effects of number of locations and sampled animals on the outcome of habitat-selection analyses. We evaluated whether tracking frequency and sample size of individuals influenced our ability to detect habitat selection. We used data obtained from adult female moose fitted with GPS collars to generate data sets simulating various sampling frequencies and sample sizes of individuals. Tracking schedules conformed to those commonly used in ungulate telemetry studies (1 location every 14, 7, or 3 d and 1 or 3 locations per d) as did animal sample sizes (between 8 and 20 individuals). We determined habitat use and availability at the landscape and home-range scales during summer-autumn and winter. Precision of habitat use and availability estimates did not improve markedly with increasing tracking frequency. Only results obtained with the least-intensive tracking schedule (1 location every 14 d) differed from those obtained with the other schedules and only in 25% of the cases. Above this threshold in tracking frequency, number of sampled animals was clearly more important than number of locations in detection of habitat selection. Our results indicated that habitat-selection analyses were more sensitive to inter- than intra-individual variability. Depending on study objectives, it may be more profitable to prioritize number of sampled individuals rather than number of locations per individual. We suggest methods allowing researchers to assess inter-individual variability while studying habitat selection. [ABSTRACT FROM AUTHOR]

We studied the population dynamics of snowshoe hare in 2 areas of the southern boreal forest of eastern North America that differed with respect to furbearer harvest. We predicted that hare density and survival would be higher in the area with trapping (TRAP) than in the protected area (PROT) as a response to differential predator abundance. Indices of predator density suggested that predation risk was slightly higher in PROT than TRAP, particularly during the first year of our 3-year study. Predators killed 86% of the radiomarked hares (body mass >900 g) that died during the study (n = 71). Hare density was higher in TRAP (56 ± 4 hares/100 ha) than PROT (30 ± 5 hares/ 100 ha). Furthermore, hare densities were relatively stable in both areas between 1998 and 2000. Additional data from the previous 2 years in TRAP indicated that hare density had remained relatively unchanged for 5 years. These findings were in agreement with regional trends in hunter harvests which were low and stable throughout the 1990s. Annual survival of radiomarked hares (>900 g) was high in both areas but decreased during the study. Survival exhibited a sex*area interaction, and was lower for females in TRAP than PROT (46% vs. 76%) but higher for males in TRAP than PROT (64% vs. 37%); hare survival did not differ when sexes were combined. Differential survival of older hares could therefore not explain the difference in hare densities in the 2 areas. Gestation rates were similar in both areas, but the numbers of young hares (300-900 g) entering the population and young: female ratios were higher in TRAP than PROT. Survival of young hares during their first summer was variable between time periods, and tended to be higher in PROT than TRAP Thus, it is likely that improved survival of juveniles (<300 g) soon after birth explains the increased hare density in TRAP. Study results show that managers cannot assume the existence of cyclicity in all hare populations, and must be aware that complex trophic interactions can generate unexpected responses to perturbations. [ABSTRACT FROM AUTHOR]

Presents information on a study which compared the influence between satellite geometry and differential correction on Global Positioning System location accuracy. Methodology; Results of the study; Discussion.

Ecological theory predicts that the intensity of antipredator responses is dependent upon the spatiotemporal context of predation risk (the risk allocation hypothesis). However, most studies to date have been conducted over small spatial extents, and did not fully take into account gradual responses to predator proximity. We simultaneously collected spatially explicit data on predator and prey to investigate acute responses of a threatened forest ungulate, the boreal caribou (Rangifer tarandus), to the spatiotemporal dynamics of wolf (Canis lupus) distribution during spring. Movement analysis of GPS-collared individuals from both species revealed high plasticity in habitat-selection decisions of caribou. Female caribou avoided open areas and deciduous forests and moved relatively fast and toward foraging areas when wolves were closer than 2.5 km. Caribou also avoided food-rich areas only when wolves were within 1 km. Our results bridge the gap between long-term perceived risk and immediate flight responses by revealing dynamic antipredator tactics in response to predator proximity. [ABSTRACT FROM AUTHOR]

We tested for fine-scale spatial heterogeneity in habitat quality in a roe deer (Capreolus capreolus) population in the Chizé reserve located in western France by measuring spatial variation in the availability and plant nitrogen content of principal and preferred plant species. There were significant differences in habitat quality within the reserve: the principal food plants in spring and summer occurred more frequently in the oak woodland in the north than in the beech woodland in the south of the reserve. Within species, plants in the north had higher nitrogen contents than in the south. There was a positive spatial covariation between habitat quality, local density and fawn body weight: animal densities and fawn body weights were highest in the north, the best habitat (i.e. the habitat with more abundant food of higher quality). These results differ from those recently obtained on red deer (Cervus elaphus). We suggest that spatial organization and foraging behaviour must be accounted for when considering the effect of habitat quality on individual fitness of ungulates.

We contrasted patterns of growth and accumulation of body reserves in autumn between two high-density (HD) white-tailed deer populations facing winters of different severity and length. Both populations occurred in the absence of effective predators and suffered from some forage competition based on reduced body masses. A third population living at low density (LD) and confronting long and severe winters (SW) served to distinguish the influence of food competition and winter severity on growth and body reserves. We estimated body components (water, protein, fat and ash) of deer during the first half of November and compared growth patterns between sexes and regions. HD-SW males continuted growth to an older age than HD males facing short and mild winters (MW) but females of both regions reached adult body mass at the same age. LD-SW deer exhibited a growth pattern similar to that of HD-SW animals but were the heaviest and the largest, suggesting that growth patterns are related to winter harshness (or length of the growing season) and that final body size is related to forage competition in summer. Sexual dimorphism became evident at an older age in the HD-SW population than in the HD-MW population, demonstrating that winter harshness does not affect immature males and females in the same manner. Fawns from the HD-SW population had proportionally longer legs and a higher percentage of body fat. Adaptations of immature deer to long and severe winters suggest that survival during the first winter represents the most critical step in the life span of northern white-tailed deer.

Optimality models of food selection by herbivores assume that individuals are capable of assessing forage value, either directly through the currency used in the model or indirectly through other variables correlated with the currency. Although energy and protein are the two currencies most often used, controversy exists regarding their respective influence on food choice. Part of the debate is due to the difficulty of teasing apart these two nutrients, which are closely correlated in most natural forages. Here we offer a test of the assumption that energy and protein contents of the forage are both currencies that large mammalian herbivores can use when selecting their food. We observed feeding behavior of 47 wild white-tailed deer (Odocoileusvirginianus) during winter while individuals were presented with four experimental foods representing two levels of energy and protein (dry matter digestibility: 40-50%; crude protein: 12-16%). Using experimental foods allowed us to separate the influences of energy and protein and clearly distinguish between the roles of these two nutrients. Deer discriminated between foods through partial selection, and selected diets higher in energy but lower in protein. The observed choices appeared consistent with physiological needs of deer wintering at the study site, where digestible energy was in short supply in the natural environment while protein was probably not. Results are in good agreement with recent findings on domesticated ruminants. They support a basic assumption of optimality models of food selection that use energy and/or protein as a currency, although the physiological mechanisms behind the food selection process remain unclear. We urge students of food selection by herbivores to replicate our experiment with other foods and/or in other circumstances before more general conclusions are drawn.