Stability And Change In Canada's Forested Landscapes: A Conceptual Model For Understanding Dynamic Connectivity Patterns Across Decades

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As Canada experiences climate change in coming decades, animals will be on the move. Whether encountering new neighbors venturing from the south or trying to travel into newly suitable habitat, many organisms will see their fitness linked to the paths they choose. Dispersers through forests, for example, will move through and within landscapes reflecting many historical factors including the size of past disturbances, the time since they occurred, and the forest recovery rate. Understanding the context of a landscape's connectivity will help managers to forecast and manage land to aid the long-term persistence of species in Canada. But because of the complex effects of the history of disturbance on landscapes, a fuller understanding of landscape patternsparticularly as they affect functional connectivity for organismsrequires careful study beyond a single snapshot of land cover. An effective new perspective for modeling connectivity treats landscapes like electrical circuits, with each land-cover type presenting a certain resistance to movement of a given organism. Recent work in my lab has extended this model to allow tiling of circuit-based maps across arbitrarily large areas. Yet although we can map compelling connectivity surfaces with circuit theory, it is not clear if connectivity patterns are stable or changing through time. The goal of this research is to develop and test a new conceptual model of the stability of landscape connectivity through time and across space. Over the next five years my research team of undergraduates, Master's students, PhD students, and postdocs will study the relationship between disturbance and connectivity in forested landscapes, explore the history of thousands of landscapes of Canada using satellite observations over the last three decades, and consider landscapes from a variety of organisms' perspectives. My long-term program has three medium-term objectives: (1) define measures of stability for connectivity through time in circuit-based analyses; (2) build and test a new conceptual model of dynamic landscape connectivity as a function of disturbance frequency and size; and (3) incorporate a multi-species perspective of changes in landscape connectivity through time. Our proposed model extends an influential early conceptual framework of landscape equilibrium. That model hypothesized regions of landscape stability and instability as a function of disturbance frequency and size, but did not explicitly consider the spatial patterns produced by disturbance and recovery. This work will expand that vision of equilibrium and give it spatial context, by tracing when and how a changing landscape pattern affects functional connectivity through time. The conceptual model, the new methods to support it, and the data created to test it will be an asset for the scientific community that will open long-term research avenues for ourselves and others.