PARENT SESSION
Contributed Oral Session 48: Landscape Ecology: Animal Dynamics
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 520 B, Level 5, Palais des congrès de Montréal

Modelling the respective effects of habitat loss and fragmentation on small mammals and forest birds in the Canadian boreal forest.

St-Laurent, Martin-Hugues^*,1, Dussault, Christian², Ferron, Jean¹, Gagnon, Réjean³, ¹ University of Quebec at Rimouski, Rimouski, Quebec, Canada² Ministère des Ressources Naturelles, de la Faune et des Parcs, Quebec, Quebec, Canada³ University of Quebec at Chicoutimi, Chicoutimi, Quebec, Canada

ABSTRACT- Habitat loss and fragmentation are frequently recognized as major threatening factors to biodiversity, exhibiting wildlife impacts such as decreases in population abundance and community diversity. However, an ongoing debate goes on since several years with regard to the relative importance of loss and fragmentation as perturbation processes, and their respective impacts on wildlife biodiversity and population levels. Based on empirical data collected in logged landscapes of boreal black spruce forest, we built multiple linear regression models of habitat utilization for several bird and small mammal species. The effects of these two concomitant perturbations are analyzed through a theoretical model which control for different intensities of both habitat loss and fragmentation using different landscape scenarios. A wide range of species was used according to their respective sensitivity or insensitivity to loss and fragmentation of mature forest habitat: Snowshoe hare, Red-backed vole, Spruce grouse, Swainson's thrush, Hermit thrush, Magnolia warbler, Yellow-rumped warbler, Tennessee warbler, Black-backed woodpecker, Three-toed woodpecker, Red-breasted nuthatch, Brown creeper, Ruby-crowned kinglet, Winter wren, White-throated sparrow, Boreal chickadee, Gray jay, Yellow-belied flycatcher and Dark-eyed junco. Resulting models show that species react to habitat loss and fragmentation of mature forest in relation to their specific-habitat requirements, mean home range size and dispersion capacity, and depending at which scale and intensity loss and fragmentation occur. Loss and fragmentation have various effects according to species, as some of them exhibit population declines while some others show increases in abundance. However, habitat loss can be considered as the major factor of population decreases for several of the monitored species, while fragmentation appears to have effects additive to habitat loss for some species but no impact for some others.

Key words: habitat loss and fragmentation, forest birds and mammals, boreal black spruce forest, empirical-based modelling