The many ways topography buffers responses to climate change

Abstract

During climate change, populations have two survival options - they can remain in situ and tolerate the new climatic conditions ('stay'), or they can migrate to track their climatic niches elsewhere ('go'). Staying requires broad climatic tolerances, niche shifts due to changing biotic interactions, acclimation through plasticity, or rapid genetic adaptation. Going, in contrast, requires good dispersal and colonization capacities. However, both the magnitude of climate change experienced locally and the capacities required for staying or going in response to climate change are not constant across landscapes, but affected by local microclimatic variation associated with topographic complexity. We combine frameworks from population and community ecology to develop a theory for the effects of landscape topographic complexity on the immediate stay or go opportunities of local populations and communities, and on the selective pressures that may have affected the stay or go capacities of the species. With example landscapes we present population processes and community dynamics that we expect all to be dependent on the topography of the landscape that accommodate the populations and communities. We thereafter synthesize how these topography related changes in dynamics may shape the responses of populations and communities to climate change.

We predict that populations and communities of topographically complex landscapes should be more resistant and resilient to climate change than those of topographically homogeneous landscapes. However, mass effects in heterogeneous landscapes as well as extinction lags in homogeneous landscapes may mask these landscape differences under rapidly changing climates.