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ABSTRACT: Limiting factors of caribou (Rangifer tarandus) populations vary regionally. In tundra environments, this species appears to be regulated by food, either because wolves (Canis lupus) are absent or because [...]

ABSTRACT: Ecosystem management takes into account all components of ecosystems, including people. In this context, an improved knowledge of moose (Alces alces) hunters' preferences and perceptions is a prerequisite to [...]

ABSTRACT: It has been suggested that the sex ratio should be close to parity among adult moose to ensure high productivity. When the sex ratio is female biased, the mating [...]

ABSTRACT: After the large forest fires on the Quebec Cote-Nord in the summer of 1991, a study was conducted to determine the impact on the moose harvest, and the behavior [...]

AbstractWe assessed habitat selection of moose in a study area containing 2 highways and a network of forest roads in Quebec, Canada. We tested the hypothesis that roadways would affect moose habitat selection and that moose behaviour would vary with time, proximity to roads, type of roadway, and environmental characteristics (i.e., habitat and topography). We equipped 47 moose with GPS telemetry collars and assessed habitat selection using resource selection functions. Moose searched primarily for areas with high forage availability, but they also avoided highways and forest roads, although avoidance usually disappeared beyond 100–250 m. Avoidance was not directly proportional to noise disturbance; moose systematically avoided the first 100 m adjacent to forest roads, while habitats adjacent to highway sides were sometimes used in proportion to their availability. The benefits of using habitats adjacent to highways may be greater than the costs to moose, which was not always the case for forest roads. The road-avoidance zone varied seasonally but was generally wider for males than females, suggesting that males were more sensitive to road disturbance. We believe that moose frequent highways and associated roadsides to find food and mineral salts, and possibly to reduce predation risk for females. Topography was also an important correlate of habitat selection by moose, especially for females, which had significant selection coefficients for altitude and slope in almost every season. Proper assessment of human impacts on ungulates in natural environments requires consideration of unpaved forest roads. In a study area with a small human footprint and low road density (0.16 km·km−2), moose selection patterns suggested they minimized potential risks associated with highways at the coarse scale while seeking short-term benefits of highway roadsides, i.e., sodium in vegetation and pools, at the finer spatial scale.

Logging negatively affects the threatened forest-dwelling caribou (Rangifer tarandus caribou) through its positive effects on large predator populations. As recruitment is a key component of caribou population growth rate, we assessed calving rates of females and calf survival rates during the most critical period for calf survival, the calving period. We also identified causes of calf mortality and investigated the influence of predation risk, food availability, and human disturbance on habitat selection of females during the calving period at both the home-range and forest stand scales. We hypothesized that caribou should display habitat selection patterns to reduce predation risk at both scales. Using telemetry, we followed 22 females and their calves from 2004 to 2007 in a highly managed study area in Québec, Canada. Most females (78.5?±?0.05 [SE]) gave birth each year, but only 46.3?±?8.0% of the calves survived during the first 50 days following birth, and 57.3?±?14.9% of them died from black bear (Ursus americanus) predation. At the home-range scale, caribou selected calving areas located at upper slope positions and avoided high road density areas. Surprisingly, they also selected the forested habitat type having the lowest lateral cover (mixed and deciduous stands) while avoiding the highest cover (regenerating conifer stands). At the forest stand scale, caribou selected areas located at relatively high elevations and with a lower basal area of black spruce trees. The selection of upper slope positions likely favored spatial segregation between calving females and wolves (Canis lupus) but not black bear. Our results suggest that calving females used areas from which they could visually detect approaching predators. While wolf avoidance appeared to be effective in a highly managed landscape, caribou did not appear to have adjusted their predator avoidance strategy to the recent increase in black bear abundance, who have benefited from increased food abundance. This situation requires focused attention from wildlife managers as logging activities are progressing towards the north within the core of forest-dwelling caribou range. © 2011 The Wildlife Society.

Controlled feeding experiments can provide valuable insights into food selection of herbivores. We conducted cafeteria trials on captive yearling white-tailed deer (Odocoileus virginianus) during 2 years to determine feeding preferences in relation to plant chemical constituents, i.e., nitrogen and fibers. We simultaneously offered 8 species of cultivated and wild plants in monthly foraging trials conducted from June to October. We predicted that species preferences would be positively related to protein content from June to August and to digestible energy in September and October. As predicted, crude protein (CP) was positively related to feeding preferences, particularly as summer progressed. Feeding preferences were also negatively related to fiber content, especially in early summer. Our results indicate high protein needs over the complete growing season for yearling deer but a decrease in overall plant selectivity as summer progresses. Our results also suggest that deer browsing on cultivated plants might be due to higher CP content of cultivated plants than wild plants. To prevent deer impact on crops, managers should favor regeneration of plants rich in CP content in forests. © 2011 The Wildlife Society.

AbstractAmerican marten (Martes americana) are typically associated with mature coniferous forests. Some recent results, however, suggest that marten habitat selection may also operate at a finer scale. We therefore described site characteristics of 24 martens that were radio-tracked and snow-tracked between August 2002 and March 2004. From these data we developed 2 resource selection functions, one for summer and the other for winter, using logistic regressions. In summer, selected sites were mainly characterized by abundant biomass of spruces and short (≤30 cm) herbaceous plants and low biomass of tall (>30 cm) herbaceous plants. Other factors, such as increased coniferous canopy closure and amount of coarse woody debris (CWD) and reduced lateral cover (LC5) were included in the composite model. In winter, sites with closed coniferous canopy and LC5, high snow sinking depth, greater amounts of CWD, greater basal area, and greater tree density were more likely to be visited by marten. These variables may be related to 3 factors that play roles in marten ecology: prey abundance, protective cover, and thermoregulation. Our results also show that, unlike clear-cutting with protection of regeneration and soils (CPRS) and pre-commercial thinning (PCT), partial logging techniques (PL) could maintain, under certain conditions, the structural elements required by pine marten in a managed forest. These elements would favour prey abundance and detection, protective cover, and rest and thermoregulation sites.

ABSTRACT Anthropogenic disturbances can promote establishment and growth of predator populations in areas where secondary prey can then become threatened. In this study, we investigated habitat selection of eastern coyotes (Canis latrans), a relatively new predator in the vicinity of an endangered population of caribou (Rangifer tarandus caribou). We hypothesized that coyotes in the boreal forest depend mainly on disturbed habitat, particularly that of anthropogenic origin, because these habitats provide increased food accessibility. Coyotes would likely take advantage of moose (Alces alces) carcasses, berries, and snowshoe hares (Lepus americanus) found in open habitats created by logging. To test these predictions, we described coyote diet and habitat selection at different spatial and temporal levels and then compared resource availability between habitats. To do so, we installed Global Positioning System radiocollars on 23 individual coyotes in the Gaspésie Peninsula, eastern Québec, Canada. Coyotes selected clear-cuts of 5–20 years and avoided mature coniferous forests both at the landscape and home-range levels. Clear-cuts of 5–20 years were found to contain a high availability of moose carcasses and berries, and vulnerability of snowshoe hares is known to increase in clear-cuts. The importance of these 3 food resources was confirmed by the characteristics of core areas used by coyotes and diet analysis. Moose remains were found at 45% of core areas and coyote diet comprised 51% moose on an annual basis. Anthropogenic disturbances in the boreal forest thus seem to benefit coyotes. Our results indicated that the relationship between coyotes and caribou likely involves spillover predation. This knowledge allows managers to consider spillover predation by coyotes as a possible threat for endangered caribou population when the predator depends mainly on habitat of anthropogenic origin and to suggest methods to alleviate it when developing management plans.

AbstractForest harvesting is a major cause of habitat alteration negatively affecting forest-dwelling caribou (Rangifer tarandus caribou) in the boreal forest. In order to identify female caribou habitat requirements, we conducted a fine-scale habitat selection analysis in a managed forest of eastern Canada. Five land-cover types used by 8 female caribou during 2 periods (winter and snow-free) were considered to characterize structural attributes, ground cover, and lichen abundance at 320 GPS locations and at 200 random points within home ranges. Because caribou rely on a limited food supply in winter, we predicted that they would select sites of higher biomass of terrestrial and/or arboreal lichens. Since female caribou (especially those with calves) are more vulnerable to predation during the snow-free period, we predicted that they would select sites where predation would be reduced by a denser hiding cover (i.e., high basal area, shrub height, and/or lateral cover) or by a lower forage availability for alternative prey (i.e., low shrub density). Within each land-cover type, comparisons between used and random sites were conducted using an exploratory PCA analysis followed by conditional logistic regressions. Our results demonstrated that, in winter, female caribou selected sites with higher terrestrial lichen biomass or ericaceous shrub cover in old spruce stands and old cutovers. During the snow-free period, female caribou did not select sites of denser hiding cover. However, well-regenerated shrub layer was avoided during both periods, suggesting that caribou avoided sites containing abundant forage attractive to moose and, consequently, wolf. At a fine scale, forest management should focus on protecting sites or stands with a high biomass of terrestrial lichens. Silvicultural practices that prevent cutovers from regenerating into areas with abundant moose forage should also be favoured.

AbstractLong snowy winters combined with a short growing season make boreal forests an unproductive environment that challenges black bears (Ursus americanus).We used resource selection functions (based on GPS telemetry of 16 bears), diet analysis, surveys of plant phenology, and vegetation inventories to study adaptations of black bears to boreal forest. Because plants are heavily favoured in bear diets, we expected diet composition to reflect their temporal availability. We anticipated that bears would make choices among land cover types and specific topographic conditions in order to select plants that would fulfil their energetic demands throughout the active period. We also predicted that bears would select habitats modified by insect outbreaks or forest harvesting because these disturbances likely increase resource availability. We found supporting evidence for all of our predictions. (1) Bear diet was closely linked to plant availability. (2) Bears made seasonal altitudinal movements and selected sites according to solar irradiation, tracking the availability of the most digestible plants. Accordingly, bears relied on high-altitude graminoids in spring, a variety of fleshy fruits in summer, and mainly Sorbus americanaberries in autumn. (3) Land covers resulting from clearcutting and insect outbreaks increased resource availability for bears and were preferred from summer to autumn. In our study area, black bears are considered predators of a threatened caribou (Rangifer tarandus) population. Even so, we did not find any caribou remains in bear scats. However, our results show that forestry practices, such as clearcutting near the caribou range, could contribute to increased bear presence and thus increase the probability of predation.

AbstractAmerican marten (Martes americana), a species sensitive to intensive logging, is often associated with old-growth coniferous forest. Recent results, however, question the specificity of this association. We studied habitat selection of marten at the southern fringe of the boreal forest, in mixed forest types. The presence of a white-tailed deer (Odocoileus virginianus) wintering area protected part of the study area from large-scale intensive logging [clear-cuts with protection of regeneration and soils (CPRS) and precommercial thinning (PCT)] but not from partial logging of mature coniferous stands. We radio-tracked 15 marten over 2 y and analyzed habitat selection at 2 scales: landscape and home range. Marten selected mature (> 60 y) coniferous forests at both scales, while they neither selected nor avoided Mature mixed forests. PCT forests (0–15 y old) were strongly avoided at the landscape scale (P < 0.001), as were Young forests (21–60 y old; P= 0.005). At the home range scale, marten avoided CPRS (0–20 y old; P< 0.001). Partial logging had no effect on selection at either scale. Female home ranges were smaller in the partially logged sector of the study area (2.6 ± 0.6 versus7.4 ± 0.2 km2), while male home range averaged 5.5 ± 1.0 km2, resulting in a significant interaction between location of home ranges in the white-tailed deer wintering area and sex of individuals (F1,11= 5.618, P= 0.037). Also, home ranges tended to be larger as the road density and proportion of light outbreak cover type increased. Our results showed that partial logging, CPRS, and PCT have different impacts on marten habitat selection and use of space. We conclude that partial logging rather than clear-cuts and precommercial thinning should be favored for conservation of American marten.

AbstractRoads often negatively affect terrestrial wildlife, via habitat loss or fragmentation, noise, and direct mortality. We studied moose (Alces alces) behavior relative to a road network, in an area with a history of moose-vehicle accidents, to determine when moose were crossing roadways or using areas near roads and to investigate if environmental factors were involved in this behavior. We tracked 47 adult moose with Global Positioning System collars in a study area crossed by highways and forest roads. We hypothesized that moose would avoid crossing roads but would make occasional visits to roadsides to feed on sodium-rich vegetation and avoid biting insects. Further, we expected moose avoidance to be greater for highways than forest roads. We recorded 196,710 movement segments but only observed 328 highway and 1,172 forest-road crossings (16 and 10 times lower than expected by chance). Moose usually avoided road proximity up to =500 m on each side but 20% of collared moose made visits to areas within 50 m of highways, which might have resulted from moose searching for sodium in vegetation and roadside salt pools. In fact, vegetation along highways had higher sodium concentrations and was browsed in similar proportions to vegetation in adjacent forest, despite moose avoidance of these zones. Moose, however, did not use areas near roads more during periods of biting insect abundance. Our results supported the hypothesis of scale-dependent selection by moose; avoidance of highways at a coarse scale may confer long-term benefits, whereas selection of highway corridors at finer scales may be part of a strategy to overcome short-term limiting factors such as sodium deficiency. We found a positive relationship between home-range size and the proportion of road axes they contained, suggesting that moose either compensated for habitat loss or made specific movements along highways to gather sodium. The presence of sodium along highways likely increases moose-vehicle accident risks. Removal of salt pools or use of a de-icing salt other than sodium chloride should render highway surroundings less attractive to moose.

Abstract:Sodium has many fundamental physiological functions in animals but is rare in boreal ecosystems where moose (Alces alces) thrive. In Québec (Canada), sodium is readily available in aquatic vegetation and in salt pools that form along highways. We do not know if moose are adopting specific behaviors to access sodium sources or if they simply use the sodium sources they encounter during their movements. We tested the hypothesis that moose modify both space and habitat use to gather sodium from salt pools. We expected moose to use salt pools mostly in spring and early summer, when needs are greatest and before aquatic vegetation has fully developed. We fitted 47 moose with Global Positioning System telemetry collars and collected data for 2 to 36 months between 2003 and 2006. We rarely located moose at salt pools (0.12% among the 95,007 locations collected). As we expected, use of salt pools was highest in late spring and in early summer, and we observed a time lag between peak use of salt pools compared to use of lakes and waterways, indicating moose fulfilled their sodium requirements in salt pools before aquatic vegetation was available. Moose selected salt pools over lakes and waterways when these 2 sodium sources were present in their home range and moved rapidly over large distances to reach them. Our results were consistent with moose using salt pools when they are likely to be sodium deficient. Salt pools were less accessible, required long-distance movements, and were located in habitually avoided areas along highways. Elimination of roadside salt pools should be considered among strategies to reduce cervid-vehicle collision risks in boreal environments.

ABSTRACT Reduced to small isolated groups by anthropogenic habitat losses or habitat modifications, populations of many endangered species are sensitive to additive sources of mortality, such as predation. Predator control is often one of the first measures considered when predators threaten survival of a population. Unfortunately, predator ecology is often overlooked because relevant data are difficult to obtain. For example, the endangered Gaspésie caribou (Rangifer tarandus caribou) has benefited from 2 periods of predator control that targeted black bears (Ursus americanus) and coyotes (Canis latrans) in an attempt to reduce predation on caribou calves. Despite a high trapping effort, the number of predators removed has remained stable over time. To assess impact of predator movements on efficacy of a control program, we studied space use of 24 black bears and 16 coyotes over 3 years in and around the Gaspésie Conservation Park, Quebec, Canada, using Global Positioning System radiocollars. Annual home ranges of black bears averaged 260 km2and 10 individuals frequented area used by caribou. Annual home ranges of resident coyotes averaged 121 km2, whereas dispersing coyotes covered >2,600 km2. Coyotes were generally located at lower altitudes than caribou. However, because coyotes undertook long-distance excursions, they overlapped areas used by caribou. Simulations based on observed patterns showed that 314 bears and 102 coyotes potentially shared part of their home range with areas used by female caribou during the calving period. Despite low densities of both predator species, extensive movement and use of nonexclusive territories seem to allow predators to rapidly occupy removal areas, demonstrating the need for recurrent predator removals. Our results underscore the necessity of considering complementary and alternative solutions to predator control to assure long-term protection of endangered species.

AbstractWoodland caribou (Rangifer tarandus caribou), a threatened species in Canada, inhabit landscapes dominated by mature and over-mature coniferous stands and tend to avoid areas used by other cervids, wolves (Canis lupus), and humans. We hypothesized that habitat modifications through logging and forest fire alter the space-use pattern of woodland caribou and result ultimately in lowered density. To test this hypothesis, density, distribution, space-use patterns, and mortality of caribou in disturbed landscapes (DLs) and undisturbed landscapes (ULs) of central Québec were quantified by a systematic aerial survey (42 539 km2) and telemetry of 68 adult caribou females. A ground survey of terrestrial and arboreal lichens was carried out to estimate production of lichens in DLs and ULs. Three populations that occupied between 10 000 and 15 000 km2were identified in the study area. Caribou abundance was not limited by intraspecific competition for food. Production of terrestrial lichens was estimated to support 3 to 4 times the surveyed caribou density (1.2–2.1–100 km−2). Pregnancy rate was almost 100%, indicating that females were not food-limited. Space-use patterns were affected by forest disturbance. In DLs, caribou increased home range sizes and reduced fidelity to seasonal and annual home ranges, probably to avoid disturbed habitats. In response, the probability of surviving decreased with the extent of DL within home ranges. To help keep direct and indirect sources of caribou mortality at very low levels, forest management strategies should be oriented toward the protection of large interconnected blocks of forest to favour caribou spacing away from humans and predators and to maintain adequate space-use strategies.

ABSTRACT We developed and validated a density-adjusted spatial model to predict moose (Alces alces) highway-crossing probability to see if the model could be used as an index of moose-vehicle collision risk. We installed Global Positioning System telemetry collars on 47 moose in the north of the Laurentides Wildlife Reserve, Québec, for 2–36 months. We recorded only 84 highway crossings in spring (0.29% of 28,967 2-hr steps) and 122 crossings in summer (0.18% of 68,337 2-hr steps), despite a high sampling effort and having captured moose close to highways. Moose movement rates during movement steps crossing a highway were on average 3 times higher than during the steps preceding or following highway crossing. Paths used by moose when crossing a highway were characterized by a high proportion of food stands, low proportion of lakes and rivers, and topography typical of a valley. Highway-crossing sites were located in valleys with brackish pools and forest stands providing coniferous cover but a low proportion of lakes and rivers. We adjusted moose crossing probability for local variation in moose density using aerial survey data and assessed crossing probability along the highways in the entire Laurentides Wildlife Reserve. We tested the model using moose-vehicle accident data from 1990 to 2002. The relationship between the density-adjusted crossing probability and number of accidents was relatively loose at the 1-km scale but improved markedly when using longer highway sections (5–15 km; r > 0.80). Our results demonstrate that roads and their surroundings are perceived as low-quality habitat by moose. We also conclude that road segments installed along secondary valleys could be a highly strategic site to deploy mitigation measures such as fences and that it could be desirable to increase the width of road shoulders to reduce forest cover and to eliminate brackish pools to reduce cervid-vehicle collisions. We suggest using empirical data such as location of vehicle-wildlife collisions to plan mitigation measures at a fine scale.

ABSTRACT Wildlife-vehicle collisions cause numerous human fatalities and injuries, and generate considerable expenses in property damage each year. Certain characteristics of the road and its surroundings are known to have an impact on collision probability. Roadside salt pools increase the risk of collision by attracting moose (Alces alces) to the side of the road. In the Laurentides Wildlife Reserve of Québec, Canada, roadside salt pools were drained and filled with rocks to deter moose from drinking. We surveyed 12 roadside salt pools during 3 consecutive summers (2003–2005) from mid-May to mid-August. Seven salt pools were managed in autumn 2004, and 5 pools were left untreated. We equipped all 12 sites with electronic apparatus that allowed us to detect moose attendance and study their behavior. We also measured physical, chemical, and environmental characteristics of these pools and other unvisited pools in order to correlate moose attendance with specific habitat criteria. We found that moose mostly attended roadside salt pools from mid-June to mid-July, with a decrease in August. Moose attendance was significantly correlated with visual obstruction toward the road and water availability. Management of the pools caused a decrease in mean length of time moose spent at them. Number of visits decreased significantly at night (by 90%), which was when most visits occurred, but not during the day. The proposed management practice prevented all visiting moose from drinking brackish water. These results suggest that moose should eventually lose interest in treated salt pools, therefore decreasing the risk of moose-vehicle collisions on the road.

Abstract:We tested the effectiveness of electric fences to reduce moose (Alcesalces)-vehicle collisions in 2 fenced sectors (5 km and 10 km) using weekly track surveys and Global Positioning System telemetry. Number of moose tracks along highways decreased by approximately 80% following fence installation. Only 30% (16/53) of moose tracks observed on the road side of the fence were left by moose that crossed an operational fence; moose mostly entered the fenced corridor through openings (e.g., secondary roads) or at fence extremities. Electric fences also prevented 78% (7/9) of collared moose from crossing the highway in fenced sectors. Fences were less effective during occasional power failures. We suggest that circuit breakers should be used to prevent power failures and that there should be no opening along the fence line unless anti-ungulate structures are used.

AbstractThe 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.

Deer-vehicle accidents are an increasing problem in many regions of the world. To elaborate effective mitigation measures, it is necessary to determine environmental factors associated with the occurrence of such accidents. The Lauren-tides Wildlife Reserve in Quebec, Canada, is a prime example of an area having a long-lasting problem of moose-vehicle accidents (MVAs). We tested the effect of the spatial and temporal variables most likely to influence MVAs in this area based on accidents recorded over a 13-year period. Data collected included the date and time of each collision as well as the position of the accident relative to the closest 1-km road marker. We calculated 10 variables to assess moose habitat suitability, moose density, topography and road design for every 1-km road segment. There was a total of 754 MVAs during 1990–2002. The period with the highest number of accidents was the second half of June but accident frequency remained relatively high from mid-May to late August. The risk of accident per vehicle was at least 2–3 times higher at night (when traffic volume was lowest) than during any other time of the day. Also, MVAs were over 42% more frequent on Fridays, when road traffic levels were highest. The probability of an MVA increased when air temperature and atmospheric pressure were high. The MVA rate increased with moose density, in the presence of at least one brackish pool (by 80%) and when a valley traversed the road (by 120%). Implications of our results in the choice of appropriate mitigation measures are discussed. Future work should aim to describe habitat characteristics at the actual collision site.

AbstractWe 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.

We tested whether snow-urine ratios to creatinine of urea nitrogen (U:C), potassium (K:C), allantoin (A:C) and 3-methylhistidine (M:C) could be used to determine when to initiate an emergency feeding program in white-tailed deer Odocoileus virginianus. Food distribution to 11 experimental adult deer was gradually reduced over 64 days to simulate the conditions occurring for wild deer during winter. At the end of the partial fasting period, experimental deer had lost 19% of body mass on average. The animals were then fed ad libitumduring a 13-day recovery period. A control group of four deer was fed ad libitumduring the entire study. Control deer lost 6% of body mass during the experiment. Results for U:C and K:C ratios suggest that they were unreliable as indicators of physical condition of white-tailed deer during winter, at least within the physiological range and sample size considered in this study. A:C ratios showed fluctuations that were congruent with current knowledge of fasting physiology. A:C ratios of experimental deer relative to control deer, however, increased significantly only after 64 days of partial fasting, when animals had lost 19% of body mass. At that time it may already be too late to launch an effective feeding program. K:C and A:C ratios also increased during the recovery period, illustrating the potential difficulty of determining whether such an increase results from starvation or from resumed food intake. Concentrations of 3-methyl-histidine in the snow remained too low to be detected, due to dilution. We conclude that, under the limits of this study, none of the creatinine ratios represents an accurate index of body condition to determine when to initiate an emergency feeding program.

Abstract:In winter ungulates must compete for forage of low quality that may be energetically costly to obtain due to high locomotion costs associated with snow. We hypothesized that white-tailed deer would select plant species and plant parts to maximize their net energy budget based on snow conditions and forage availability. We predicted that as winter progress or under deep snow conditions, deer would 1) reduce selectivity, 2) enlarge bite size, and 3) increase cropping rate. For three winters, we studied white-tailed deer found in the Pohénégamook wintering area (southeastern Québec), at the northeastern periphery of the species range. Utilization rates of plant species varied in relation to fibre contents but were not related to protein, ash, or phenolic contents, suggesting that energy represented the key nutritive element during winter. Deer were less selective as winter progressed and snow depth increased. Deer consumed all available plant species, but their foraging strategy was centred around deciduous twigs; deer were reluctant to increase the amount of coniferous twigs in their diet. However, snow conditions affected diet composition. During a very mild winter, deer reduced their intake of balsam fir and consumed some species that were likely unavailable when snow was deep. Bite size increased over the winter, whereas cropping rate increased with snow sinking depth. To cope with changing locomotion costs in snow, white-tailed deer adjusted three variables: travelling distance, forage intake, and cropping rate.

Abstract:Coyotes (Canis latrans) have expanded their range to the north and east in North America during the last century. It has been suggested that vegetative cover reduces hunting efficiency of forest-dwelling coyotes, which could explain their lower performance compared to rural coyotes. Also, in their northern range, coyotes must periodically cope with deep and soft snow conditions for which they are not morphologically adapted. We snow-tracked coyotes in a forested landscape of southeastern Québec to test the hypothesis that coyotes modify their hunting strategy with respect to vegetative cover, snow condition, and hare distribution (Lepus americanus), the main prey species during winter in our study area. When snow sinking depth hampered mobility, coyotes used habitats with the lowest snow sinking depth (coniferous habitats) in a greater proportion than availability (47.0 versus29.7%), despite dense lateral cover. As a result, coyotes chased hares over short distances (17 m on average). However, when snow conditions did not hamper mobility, use of coniferous habitats decreased to 18.5% in favour of open habitats, which were used more than availability (47.7 versus32.5%), despite low hare abundance. Use of sites with little lateral cover and low sinking depth facilitated long chases by coyotes (126 m on average). Throughout winter, coyotes used sites characterized by less lateral cover and lower snow sinking depth than random sites. Our results suggest that coyotes selectively used habitat and hunting strategy to maximize their net energy budget throughout winter. Fragmentation of forest landscapes generates abundant openings and small refuges which may benefit coyotes to the detriment of native prey populations.

Abstract:We tested four predictions derived from the hypothesis that the guild of avian and terrestrial predators should regulate small mammal populations at low densities in relatively productive ecosystems of the southeastern part of the North American boreal forest. We estimated the density of two small mammal populations and the abundance of their predators for 3 y in two adjacent areas that differed with respect to trapping of furbearers. We predicted 1) that small mammal densities would not show multi-annual fluctuations in the two areas and 2) that densities would be much lower than peak densities reached by cyclic populations. Due to the harvest of furbearers in one area, we also predicted 3) that population densities and 4) survival of small mammals would be higher in the trapped than in the protected area. In agreement with our first two predictions, densities of the two main small mammal species (southern red-backed vole, Clethrionomys gapperi, and deer mouse, Peromyscus maniculatus) showed little variation between 1998 and 2000 in both areas, and additional data from the two previous years in the trapped area indicated that densities remained relatively stable and low over the 5-y period. However, contrary to our last two predictions, densities of the two most abundant species did not vary between areas, nor did survival rate of red-backed voles, the only species for which this variable could be estimated. Our findings show that the effect of trapping did not cascade down to small mammals. We have some evidence based on snow-tracking data that trapping, which focused on large generalist predators, may have relaxed intra-guild predation on small specialist predators and favoured an increase in abundance of specialist predators. Accordingly, we cannot reject the idea that a predation-based mechanism maintains small mammal densities at relatively low and stable levels in productive forests.

Abstract:Among ungulate species living in boreal regions, moose (Alces alces) are most likely to suffer from heat stress since they have a relatively low upper critical temperature (14 °C in summer and -5 °C in winter). We tested the hypothesis that moose adopt behaviours to reduce thermoregulatory costs. We predicted that moose exposed to high intensities of solar radiation or high air temperatures would 1) seek a type of vegetation association that provides thermal shelter and 2) reduce activity. We also predicted that these behaviours would be most evident in summer. Thermal-shelter use and activity of 30 free-ranging moose were measured over 3 y in a 940-km2study area of boreal forest using GPS telemetry collars. The effect of solar radiation and air temperature on thermal-shelter use and activity were assessed using logistic and multiple regression analyses. Habitat use and activity rates of moose were related to air temperature but not solar radiation. The probability of finding moose in thermal shelters increased with air temperature in summer and fall. Moose activity did not decrease as air temperature increased, but it increased at night during hot periods. As expected, moose response to thermal conditions was most noted in summer. Our results suggest that moose reduce exposure to thermal stress by using thermal shelters during the day and by increasing nocturnal activity. These behavioural adaptations allow moose to cope with thermal stress on a small temporal scale. Negative effects of heat stress could be important in areas where air temperatures are very high for extended periods of time or where thermal cover is scarce.

Abstract:The role that limiting factors play in population dynamics and the physical condition of animals may be easier to detect at the edge than the centre of a species’ range. We took advantage of a density cline at the periphery of distribution range of white-tailed deer to study trophic interactions between this herbivore and understory vegetation. We tested the hypothesis that the availability of summer forage in woodlands for this selective browser determines adult body size through density-dependent forage consumption during growth. We predicted 1) a change of forest composition resulting from persistent selective browsing; and 2) a negative relationship between the size of fully grown deer and the intensity of forage competition in summer. We estimated deer population density, carcass mass at maturity, and standing biomass of vegetation in 13 zones throughout the range of the deer in Québec, which covers 128,000 km2. Asymptotic carcass mass was related to body length, and to a lesser extent to percent body fat, and reflected size of fully grown deer. Plant biomass varied with respect to deer density, but the direction and intensity of the relationship depended on deer preference for various plant groups. Occurrence of preferred taxa decreased with increasing deer density. Forage competition in summer was related negatively to deer size, which declined sharply when there was < 10,000 kg of forage per deer. In the trade-off between growth and body reserves, the size of mature deer is likely adjusted to forage intake in order to balance absolute nutrient needs, a response allowing increased foraging efficiency of depleted resources.

Abstract: We compared habitat use, home range size, movements, and activity during summer between rural (12 animals km-2) and forest (<; 1 animal km-2) white-tailed deer populations, hypothesizing that competition for natural forage at high density would influence deer behaviour. Biomass of preferred forage at forester sites was 6 times greater in the forest than in the rural landscape. Forest deer avoided conifer and mixed stands, whereas rural deer tended to avoid stands of shade-tolerant hardwoods. Rural deer intensified their use of cultivated fields at night and ate a greater variety of native plants than forest conspecifics, including species rarely consumed by forest deer (e.g.,ferns). Rural deer used smaller home ranges but moved at a greater rate than forest counterparts. Activity pattern of deer did not differ between the two landscapes, with peaks at dawn and dusk. Our results suggest that rural deer adapted to the rarity of natural forage by exploiting agricultural crops.

AbstractCoyotes, which originate from central and southwestern North America, recently extended their range into forests of the Northeast. Forest coyotes occur in lower densities, have lower body reserves, and consume more fruits during summer than their counterparts occupying adjacent rural landscapes. We hypothesised that the forest landscape offered less animal prey to coyotes during summer than did the rural landscape. Coyote densities were higher in the rural landscape (2.7 animals 10 km-2) than in the forest landscape (0.5 animals 10 km-2) during the summer of 1997. During the summers of 1996 and 1997, coyotes in both landscapes fed mainly on wildberries (< 45% of dry matter intake), small mammals (< 10%), and snowshoe hare (< 10%). The biomass of the most abundant animal prey, snowshoe hares, was greater in the forest landscape (1.24 and 1.53 kg ha-1in 1996 and 1997, respectively) than in the rural landscape (0.46 and 0.40 kg ha-1in corresponding years). The biomass of the other major animal prey (small mammals), was comparable in both landscapes but irrupted during the second summer (0.09 and 0.50 kg ha-1in 1996 and 1997, respectively). The biomass of fruits remained relatively constant in the rural landscape during the summers of 1996 and 1997 (ª 6 kg ha-1), but it tripled in the forest landscape during the second year (1.69 kg ha-1in 1996 versus 5.30 kg ha-1in 1997). Contrary to our prediction, the availability of animal prey in the forest landscape exceeded that in the rural landscape. Our results illustrate that the presence of prey does not correspond to its availability to predators. Coyotes appear poorly adapted for hunting in dense forest vegetation during summer and compensate for shortage of animal prey by consuming more berries.

AbstractWe compared rural and forest coyotes in northeastern North America under the hypothesis that the forest landscape represents a marginal habitat for this species. We predicted that forest coyotes would have larger home ranges and higher rates of mortality and/or emigration than rural coyotes. We also predicted that coyotes would select for open habitats in both landscapes throughout the year, and would not follow white-tailed deer in their migration to wintering areas. Forest (n= 14) and rural (n= 10) coyotes foraged over 89 and 27 km2, respectively, during the trapping season (18 October - 1 March), and over 111 and 48 km2during the rest of the year. Annual survival rate did not vary significantly (P= 0.34) between adult forest and rural coyotes, averaging 74% and 60%, respectively; pups died at a higher rate in both landscapes (P< 0.01). All monitored coyotes died from anthropogenic factors, mostly from trapping. Forest coyotes exhibited a tendency to disperse and to make forays in the rural landscape where some died. We detected no selection for open habitats, irrespective of season or landscape, nor did coyotes show a strong preference for deer wintering areas. However, coyotes with deer wintering areas in their home ranges intensified their use of these areas when deer concentrated in them between December and April. We conclude that the forest landscape of northeastern North America possesses a low carrying capacity for coyotes even in the absence of wolves. We also conclude that eastern coyotes cannot replace gray wolves in this biome, and we speculate on the consequences of the arrival of this new predator for the conservation of other mesocarnivores.

AbstractDuring two growing seasons, we evaluated forage quality (in terms of digestibility and nitrogen content) of eight (five woody and three herbaceous) native species of plants commonly consumed by white-tailed deer (Odocoileus virginianus) at four sites along a climatic gradient. At one site, we also compared the composition of native forages of deer with that of three cultivated species consumed occasionally by deer. We predicted that forage quality would improve with increasing latitude because the cool climate and short growing season should allow forage to remain more digestible during the period of availability. We also predicted that the quality of cultivated plants should be higher than that of forest plants throughout the growing season, and particularly towards its end, because of successive harvesting of cultivated plants. Depending on the plant species, estimated dry-matter digestibility varied between 55.2% and 79.2%, whereas nitrogen content averaged between 0.7% and 5.7%. Both variables decreased progressively throughout the summer. Our results did not support the first prediction despite a reduction of 50% in the number of degree-days between the southern and the northern extremes of the climatic gradient. Inter-annual climate variations may have masked subtle differences in plant quality between sites. As predicted, cultivated forages tended to be of higher quality than native species growing in neighboring woodlots, and particularly at the end of the summer because of mowing and regrowth. Our results indicated that white-tailed deer living at the northern fringe of their range cannot count on highly digestible forage to compensate for the short growing season.

Abstract: 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.

Abstract:Biomass and distribution of arboreal fruticose lichens were studied along two environmental gradients, height along vertical tree axis and altitude, in an old growth balsam fir (Abies balsamea[L.] Mill.) forest in the McGerrigle Range, Gaspé Provincial Park, Québec. Biomass was estimated by subsampling 53 balsam firs selected from five plots, systematically distributed along an elevational transect. Three vegetation belts (mountain, subalpine, and alpine) located between 720 and 1068 m (above sea level) were sampled. Alectoria sarmentosa, Bryoria spp. and Usnea spp. represented the bulk of epiphytic lichen vegetation. Both gradients influenced lichen biomass and species diversity on balsam fir. The bulk of lichen biomass was found at intermediate heights in trees. In the mountain belt, the number of lichen species was positively correlated with tree height and diameter. Total lichen biomass on trees was predicted by tree diameter and vegetation belt (ln[biomass + 1] = 2.91x+ k; R2= 0.87; k= -2.07, -3.4, or -5.2 in the mountain, subalpine and alpine belts, respectively). In the same order, estimates of total lichen standing crop were 1306 kg/ha, 150 kg/ha and 11 kg/ha. Decrease in lichen biomass in the alpine and subalpine belts may be related to decrease of tree size, harsh environmental conditions and caribou grazing.

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