Year of Award
Dissertation - Campus Access Only
Doctor of Philosophy (PhD)
Fish and Wildlife Biology
Department or School/College
College of Forestry and Conservation
Winsor Lowe, Paul Lukacs, Kevin McKelvey, Michael S. Mitchell, Marco Musiani, Jesse Whittington
University of Montana
Large carnivores play important roles in structuring ecosystems, but carnivores are often the first species lost from an ecosystem. Carnivores are important conservation tools to protect, garner support for, and indicates changes in, biodiversity. One of the challenges in understanding both the ecological and conservation roles of carnivores, however, is that they tend to be rare and elusive. Furthermore, the need for conservation is increasing while budgets for conservation remain tight. Efficiency is needed to monitor multiple carnivore species. Remote cameras may offer an efficient means to meet these challenges collecting data simultaneously on many species. Data from cameras for species that are not uniquely identifiable can be used to estimate occupancy, i.e. the proportion of area occupied. Occupancy data is cost-effective and a recommended state variable to monitor population trends.
As with any new monitoring method, prospective power analysis is essential. Using n = 183 remote cameras across 5 national parks, I test how camera-based occupancy models can monitor changes in grizzly bear occupancy. As hypothesized, statistical power increased with both the number of cameras and the number of days cameras were deployed, but power was not affected by the ecological mechanisms of decline. Furthermore, when monitoring multiple species, species-specific occupancy and detection probability estimates can affect statistical power. I also examined how sampling scales define occupancy and occupancy-abundance relationships (OA) in mobile animals. I found that the temporal scale of sampling greatly affected the definition of occupancy, which ranges from occupancy of single or multiple individuals, to partial use by one individual or many individuals. With point-sampling, however, spatial grain had little affect on occupancy estimates or the OA relationship, helping pave the way for robust multi-species monitoring.
Ideally, multiple-species monitoring can also provide information on how species interact in food-webs. Using occupancy models for 16 mammal species in the Canadian Rockies (n = 698 cameras), I compare carnivores as candidate umbrella species and assesses their ecological role in food-web structure. Grizzly bear occupancy was highly correlated with other species’ occupancy, but wolves were more correlated with how food webs changed across the landscape. This corroborates the importance of wolves as a keystone species and advances the umbrella-species concept beyond conserving biodiversity. With the insights gained from my research, camera networks can be easily scaled-up to monitoring the planet's biodiversity. Remote cameras excite public support to ultimately help make successes in global conservation possible.
Steenweg, Robin Willem, "LARGE-SCALE CAMERA TRAPPING AND LARGE-CARNIVORE MONITORING, OCCUPANCY-ABUNDANCE RELATIONSHIPS, AND FOOD-WEBS" (2016). Graduate Student Theses, Dissertations, & Professional Papers. 10903.
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© Copyright 2016 Robin Willem Steenweg