Biodiversity and consumer-resource interactions in fractal landscapes

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A central question in ecology is how scale and environmental heterogeneity affect populations, trophic interactions and biodiversity. Answering this question partly requires knowing the scale at which species sample their resources (food) and how this affects the behaviour of consumers (minimum patch size requirements or giving up density) or the assemblage of species in a community (biodiversity). Heterogeneity in the distribution of resource patches can be described by fractal geometry and scales with body size of consumers as well as foraging behaviour and patch occupancy since organisms sample their environment at a perceptual grain that relates to their foraging efficiency. Scales at which organisms perceive and use a resource also helps explain patterns of coexistence of species in a community since they may not directly compete for the same resource.A number of neutral theories of biodiversity, including island biogeography (IBG), ignore these trait-based explanations of community assembly, as well as interactions with disturbance in fragments. When disturbances are positively related to fragment (patch) size, local extinction rates can increase resulting in a paradox in IBG theory since biodiversity under these conditions may be inversely related to fragment (island) size. Little is known about how common this paradox is, how different taxa respond relative to life history traits (body size, longevity, etc.) and whether regional metacommunity and metapopulation or source-sink dynamics can compensate for higher extinction rates via a ‘rescue effect’. My long-term research objective is to understand processes relating to the distribution, dynamics and interactions of species and ecosystems and to use this to inform biodiversity conservation. Specifically, I am interested in how scale and heterogeneity in space and time affect populations, behaviours of individuals, plant-animal (trophic) interactions and species assemblages (biodiversity). I propose to address this research objective by examining the following two complimentary research questions: 1. How does the spatial and temporal heterogeneity in a key resource (buffaloberry) affect a consumer dependent on that resource (grizzly bears)? 2. How do disturbances (fires) interact with fragmentation (scale) to affect biodiversity patterns?Research on these two questions will be carried out as a series of related research projects resulting in the training of 2 PhD, 3 MSc, numerous undergraduate students (~10), and 1 post-doctoral fellow. These projects will provide training opportunities in experimental design, field research (taxonomy, sampling, safety and logistics, etc.), use of novel and emerging research tools (i.e. Unmanned Aerial Vehicles [UAVs] for high resolution remote sensing and 3D modeling), analysis (modeling and statistics) and hypothesis testing. This work will also add knowledge about how heterogeneity and scale affects consumer-resource interactions and biodiversity. Both themes have real-world applications to the management of threatened species and biodiversity in Canada, including management of a locally threatened high profile species (grizzly bears) and biodiversity conservation in the western boreal forest which is being increasingly fragmented by resource development and threatened by rapid environmental change. Understanding and mitigating these effects are needed to support sustainable resource management and Canada’s environmental reputation.