UBC Theses and Dissertations
Seismic consequences : large mammal community dynamics in a boreal working landscape Tattersall, Erin Ruth
Anthropogenic landscape change modifies the face of our planet, creating new playing fields on which wildlife communities respond to altered landscapes. Individual species react to disturbance, which trigger subsequent responses in their interactions with other species and thus propagate effects across ecological communities. In Alberta’s boreal forest, resource extraction has created a working landscape: a heterogeneous mosaic of natural and industrial features. The most pervasive industrial features are seismic lines – long trails cut for oil and gas exploration. Mammal community responses to seismic lines have contributed to population declines for the iconic woodland caribou (Rangifer tarandus caribou), thus motivating mitigation strategies in the form of habitat restoration. Although restoration is promised to recover caribou and restore landscape functionality, effective restoration should change wildlife responses to seismic lines, yet such responses are rarely evaluated. Further, interspecific interactions on the working landscape must be analyzed to understand how differential behavioural responses across species influence community dynamics. Using camera traps in northern Alberta, I investigated how large mammals respond to human landscape change at the behavioural and community levels. I first examined seismic line use by caribou, caribou predators, and caribou apparent competitors following restoration. Three years after treatment, white-tailed deer (Odocoileus virginianus) preferred unrestored seismic lines over restored lines, while wolves (Canis lupus) strongly preferred human-use lines but did not avoid restored lines. Caribou did not respond to restoration over the study period, instead preferring seismic lines in lowland habitat. I then explored interspecific interactions, assessing how distribution of wolves influenced occurrences of black bear (Ursus americanus), coyote (Canis latrans), and lynx (Lynx canadensis) at three spatiotemporal scales. All three species showed positive associations with wolves on at least one spatiotemporal level, and black bear occurrences decreased with increasing linear density while coyote and lynx occurrences increased. Overall, I demonstrated how anthropogenic landscape change – even when implemented for conservation – induces behavioural responses that can affect community interactions and thus ripple across ecological hierarchies. These results illustrate the value of multi-species monitoring to improve understanding of community interactions, especially when making single-species management decisions that ultimately influence wildlife communities as a whole.
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