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Dussault C.,Ministere des Ressources naturelles et de la Faune du Quebec | Pinard V.,University of Quebec at Rimouski | Ouellet J.-P.,University of Quebec at Rimouski | Courtois R.,Ministere des Ressources naturelles et de la Faune du Quebec | Fortin D.,Laval University
Proceedings of the Royal Society B: Biological Sciences | Year: 2012

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. © 2012 The Royal Society.

Thompson S.L.,Natural Resources Canada | Thompson S.L.,California State University, Los Angeles | Lamothe M.,Natural Resources Canada | Meirmans P.G.,Natural Resources Canada | And 3 more authors.
Molecular Ecology | Year: 2010

As the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (Populus balsamifera, Populus deltoides) in Quebec, Canada within which European exotic Populus nigra and its hybrids have been extensively planted since the 1800s. Single nucleotide polymorphisms (SNPs) that appeared fixed within each species were characterized by DNA-sequencing pools of pure individuals. Thirty-five of these diagnostic SNPs were employed in a high-throughput assay that genotyped 635 trees of different age classes, sampled from 15 sites with various degrees of anthropogenic disturbance. The degree of admixture within sampled trees was then assessed through Bayesian clustering of genotypes. Hybrids were present in seven of the populations, with 2.4% of all sampled trees showing spontaneous admixture. Sites with hybrids were significantly more disturbed than pure stands, while hybrids comprised both immature juveniles and trees of reproductive age. All three possible F1s were detected. Advanced-generation hybrids were consistently biased towards P. balsamifera regardless of whether hybridization had occurred with P. deltoides or P. nigra. Gene exchange between P. deltoides and P. nigra was not detected beyond the F1 generation; however, detection of a trihybrid demonstrates that even this apparent reproductive isolation does not necessarily result in an evolutionary dead end. Collectively, results demonstrate the natural fertility of hybrid poplars and suggest that introduced genes could potentially affect the genetic integrity of native trees, similar to that arising from introgression between natives. © 2009 Crown in the right of Canada.

Verreault G.,Ministere des Ressources Naturelles et de la Faune du Quebec | Mingelbier M.,Ministere des Ressources Naturelles et de la Faune du Quebec | Dumont P.,Ministere des Ressources Naturelles et de la Faune du Quebec
Journal of Fish Biology | Year: 2012

Daily American eel Anguilla rostrata catches and their dates of passage (starting, median and ending dates) were compared between pristine (1843-1872) and contemporary periods (1963-1990) to determine any changes and see whether these were related to environmental variations and water discharge regulation. Timing and duration of A. rostrata migration patterns differed significantly between the two periods. the contemporary period, migrating A. rostrata were intercepted significantly earlier than pristine times (18 days earlier on average), and ended at the same average period. Early A. rostrata migration was also significantly related to high spring flow and secondarily to high spring temperature, while migration ended later when high temperature or low water level occurred during the autumn period. A recent slight increase the water temperature of the St Lawrence River could partially explathe earlier A. rostrata migration observed during the contemporary period. return, the effect of high spring flow should have been more contrasted if the river discharge would have not been regulated. Recent A. rostrata production now being mainly restricted to the lower part of St Lawrence River mainstream, resulting shorter travelling distance to the estuary may explawhy migrating progress was earlier during the contemporary period. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Mansuy N.,Natural Resources Canada | Boulanger Y.,Natural Resources Canada | Terrier A.,University of Quebec at Montréal | Gauthier S.,Natural Resources Canada | And 2 more authors.
Landscape Ecology | Year: 2014

The characterization of the fire regime in the boreal forest rarely considers spatial attributes other than fire size. This study investigates the spatial attributes of fires using the physiography of the landscape as a spatial constraint at a regional scale. Using the Canadian National Fire Database, the size, shape, orientation and eccentricity were assessed for 1,136 fires between 1970 and 2010 in Quebec's boreal forest and were summarized by ecodistrict. These spatial metrics were used to cluster 33 ecodistricts into homogeneous fire zones and then to determine which environmental variables (climate, topography, hydrography, and surficial deposits) influence the spatial attributes of fires. Analyses showed that 28 out of 33 ecodistricts belonging to a given fire zone were spatially contiguous, suggesting that factors driving the spatial attributes of fire are acting at a regional scale. Indeed, the orientation and size of fires vary significantly among the zones and are driven by the spatial orientation of the landscape and the seasonal regional climate. In some zones, prevailing winds during periods conducive to fire events parallel to the orientation of the landscape may favour the occurrence of very large fires (>100,000 ha). Conversely, an orientation of the landscape opposite to the prevailing winds may act as a natural firebreak and limit the fire size and orientation. This study highlights the need to consider the synergistic relationship between the landscape spatial patterns and the climate regime over the spatial attributes of fire at supra-regional scale. Further scale-dependant studies are needed to improve our understanding of the spatial factors controlling the spatial attributes of fire. © 2014 Her Majesty the Queen in Right of Canada.

Leclerc M.,University of Quebec at Rimouski | Dussault C.,Ministere des Ressources naturelles et de la Faune du Quebec | St-Laurent M.-H.,University of Quebec at Rimouski
Forest Ecology and Management | Year: 2012

Woodland caribou (Rangifer tarandus caribou) populations are declining worldwide, and predation is considered their most important limiting factor in North America. Caribou are known to reduce predation risk by spacing themselves away from predators and alternative prey. This strategy is now compromised by forestry activities that reduce the amount of suitable caribou habitat and trigger an increase in densities of alternative prey and predators. Our objective was to investigate the influence of predation risk and food availability on selection of a calving location by woodland caribou at three different spatial scales (from coarse to fine: annual home range, calving home range, and forest stand scales) in the boreal forest of Québec, Canada. Using GPS telemetry, we identified calving locations and assessed those using Resource Selection Functions. We determined habitat characteristics using digital ecoforest and topographic maps at the annual and calving home range scales, and with vegetation surveys at the forest stand scale. Caribou selected calving locations located at relatively high elevation and where road density was low, both at the annual and calving home range scales. Within the annual home range scale, they also selected calving locations where the proportion of young and old cutovers was lower than in random areas of similar size. At the forest stand scale, females calved away from roads and young cutovers, using stands where the basal area of black spruce and balsam fir trees was low. At this fine scale, females still selected calving locations located at a relatively high elevation and where the availability of food resources was lower than in random areas located within the same habitat type. The selection of a calving location was driven by predation risk from the largest to the finest spatial scale. Therefore, our results suggest that females may not be able to lower predation risk at larger scales, despite general avoidance of roads and cutovers. We recommend amalgamating all forestry activities within intensive management zones in order to spatially isolate large patches of suitable calving habitat from anthropogenic disturbances. If not possible, we recommend concentrating forestry activities in low-lying areas since caribou consistently selected for relatively high elevations at all scales. © 2012 Elsevier B.V.

Lesmerises F.,University of Quebec at Rimouski | Dussault C.,Ministere des Ressources naturelles et de la Faune du Quebec | St-Laurent M.-H.,University of Quebec at Rimouski
Forest Ecology and Management | Year: 2012

Throughout the southern part of the boreal forest, timber harvesting has generated a young forest matrix interspersed with mature remnants and fragmented by numerous roads. These changes have modified the abundance and diversity of many animal species and destabilized some trophic networks. Because wolves (Canis lupus) are apex predators of the boreal food web, wolf response to cumulative disturbances could have important impacts on the entire ecosystem. Our objective was to assess the impacts of anthropogenic disturbance on wolf habitat selection in a highly disturbed landscape. Between 2005 and 2010, we tracked 22 wolves with GPS collars in nine packs inhabiting the southern fringe of Québec's boreal forest. Using resource selection functions, we assessed the synergistic impacts of anthropogenic disturbances and habitat quality on habitat selection. Wolves selected areas providing food or likely to improve hunting success, but avoided anthropogenic disturbances, especially in regions with high levels of human activity. Interestingly, wolves seemed more tolerant of infrastructure when frequenting high-quality habitats. We demonstrate how anthropogenic disturbances may influence wolf habitat selection. Wildlife managers should take into account predator responses to logging-related disturbances when planning forest management for potential prey species. © 2012 Elsevier B.V.

Mansuy N.,University of Quebec at Montréal | Gauthier S.,Natural Resources Canada | Robitaille A.,Ministere des Ressources naturelles et de la Faune du Quebec | Bergeron Y.,University of Québec
Canadian Journal of Forest Research | Year: 2012

In many northern forest ecosystems, the postfire transition from a closed-crown forest to open woodland is often observed but poorly understood. This paper looks at the effect of interactions between surficial deposit, climate, and fire cycle on postfire forest recovery within a large territory (190 000 km 2) of the boreal forest of eastern Canada. Postfire recovery was estimated using the time elapsed to move from the burnt stage to the regenerated stage and the young forest stage. The main objective was to determine if forests situated in dry regions (characterized by a high proportion of dry coarse surficial deposits, low precipitation, and short fire cycle) tend to reestablish more slowly after fire, obtaining a more open stand compared with wetter regions characterized by a longer fire cycle. To identify the best explanatory model for postfire recovery, multinomial logistic regressions with the Akaike information criterion were conducted using a combination of physicoclimatic factors. Our best model suggests that the most significant predictors of postfire recovery are time since fire (χ 2 = 1370.06), surficial deposit type (χ 2 = 651.95), the Canadian Drought Code (x 2 = 247.75), and the growing season precipitation (χ 2 = 102.80). Fast recovery and dense forest regeneration are associated with subhydric till deposits only in the regions characterized by a long fire cycle (>500 years). Conversely, slow regeneration conducive to a sparse young forest was usually associated with regions characterized by a short fire cycle (<200 years) underlain by dry coarse deposits such as juxtaglacial but also mesic deposits in some cases. Our results also show that slow recovery and reduced forest regeneration are most likely to occur following fires that occurred in dry years, regardless of the deposit type and region.

Mansuy N.,University of Quebec at Montréal | Gauthier S.,Natural Resources Canada | Robitaille A.,Ministere des Ressources Naturelles et de la Faune du Quebec | Bergeron Y.,University of Québec
International Journal of Wildland Fire | Year: 2010

Spatial variations in the fire cycle of a large territory (190000km 2) located in the boreal forest of eastern Canada were assessed using random sampling points. Our main objective was to determine if regions characterised by a large proportion of dry surficial depositdrainage (SDD) burn more frequently than regions with a smaller proportion. Through a regionalisation of the landscape units, we analysed the effects of SDD on spatial variations of the fire cycle. A discriminant analysis involving the SDD and other physical variables (precipitation, temperature, aridity index, water bodies, elevation and slope) made it possible to identify a combination of variables characterising each region. A considerable variation in fire cycle was observed among the different SDD types (from 144 to 425 years) and between regions (from 90 to 715 years). Through the discriminant analysis, this study suggests that a combination of possible climatic top-down (precipitation R 2=0.727, aridity index R 2=0.663 and temperature R 2=0.574) and bottom-up factors (xeric undifferentiated till R 2=0.819 and humid undifferentiated till R 2=0.691) could explain this variation at the regional scale. Implications of those results for forest protection against fire and regional development are briefly discussed. © IAWF 2010.

Lesmerises R.,University of Quebec at Rimouski | Ouellet J.-P.,University of Quebec at Rimouski | Dussault C.,Ministere des Ressources naturelles et de la Faune du Quebec | St Laurent M.-H.,University of Quebec at Rimouski
Ecology and Evolution | Year: 2013

For conservation purposes, it is important to design studies that explicitly quantify responses of focal species to different land management scenarios. Here, we propose an approach that combines the influence of landscape matrices with the intrinsic attributes of remaining habitat patches on the space use behavior of woodland caribou (Rangifer tarandus caribou), a threatened subspecies of Rangifer. We sought to link characteristics of forest remnants and their surrounding environment to caribou use (i.e., occurrence and intensity). We tracked 51 females using GPS telemetry north of the Saguenay River (Québec, Canada) between 2004 and 2010 and documented their use of mature forest remnants ranging between 30 and ~170 000 ha in a highly managed landscape. Habitat proportion and anthropogenic feature density within incremental buffer zones (from 100 to 7500 m), together with intrinsic residual forest patch characteristics, were linked to caribou GPS location occurrence and density to establish the range of influence of the surrounding matrix. We found that patch size and composition influence caribou occurrence and intensity of use within a patch. Patch size had to reach approximately 270 km2 to attain 75% probability of use by caribou. We found that small patches (<100 km2) induced concentration of caribou activities that were shown to make them more vulnerable to predation and to act as ecological traps. Woodland caribou clearly need large residual forest patches, embedded in a relatively undisturbed matrix, to achieve low densities as an antipredator strategy. Our patch-based methodological approach, using GPS telemetry data, offers a new perspective of space use behavior of wide-ranging species inhabiting fragmented landscapes and allows us to highlight the impacts of large scale management. Furthermore, our study provides insights that might have important implications for effective caribou conservation and forest management. We propose an approach that combines the influence of landscape matrices with the intrinsic attributes of remaining habitat patches on the space use behaviour of woodland caribou using GPS telemetry surveys conducted on 51 females. We found that residual forest patch size and composition influence caribou occurrence and intensity of use within a patch, and that both the presence of anthropogenic disturbances and undisturbed areas in the surrounding environment influenced caribou use of residual forest patches. Woodland caribou clearly need large residual forest patches, embedded in a relatively undisturbed matrix, to achieve low densities as an antipredator strategy (spacing out behaviour). © 2013 The Authors.

Faille G.,University of Quebec at Rimouski | Dussault C.,Ministere des Ressources naturelles et de la Faune du Quebec | Ouellet J.-P.,University of Quebec at Rimouski | Fortin D.,Laval University | And 2 more authors.
Biological Conservation | Year: 2010

Conservation of forest-dwelling caribou (Rangifer tarandus caribou) is of great concern across most of its range. Anthropogenic disturbances, primarily logging activities, have been identified as the most important cause of caribou decline, although the mechanisms underlying this decline are not fully understood. Caribou commonly display fidelity to calving sites or seasonal ranges, but the potential role of this life-history trait has been largely overlooked in research and conservation planning. This is surprising because sites and ranges with high inter-annual use should have high conservation value. We investigated the relationship between habitat disturbances and home-range fidelity of forest-dwelling caribou across three study sites in Québec, Canada, using a broad range of natural and anthropogenic disturbances. Between 2004 and 2007, we tracked 47 adult female caribou using GPS collars. Home-range fidelity varied between seasons, being higher during calving and summer, and lower during winter. Caribou reduced fidelity following natural and anthropogenic disturbances, the latter having a stronger negative influence. Anthropogenic disturbances had a strong negative impact on home-range fidelity during annual, summer and winter periods, whereas natural disturbance was the dominant factor during calving. Despite this negative influence on fidelity, caribou tended to demonstrate range fidelity even in study sites most impacted by human activities. Habitat disturbances could produce two possible outcomes for caribou conservation: (1) a trend for females to reduce home-range fidelity which could translate into lower calf and female caribou survival through reduced familiarity with food distribution, escape cover and predation risk and (2) a global tendency to maintain range fidelity even in a drastically modified landscape which could turn into an ecological trap, particularly for calves when predation risk increases due to increased black bear density in early successional forests. Taking range fidelity behavior into consideration during forest management planning could direct conservation efforts toward the best available sites and therefore facilitate caribou persistence in managed landscapes. © 2010 Elsevier Ltd.

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