Landscape connectivity to address climate change: tracking climates through time and space

Caitlin Littlefield (1), Julia Michalak (2), Brad McRae (3), Joshua Lawler (4), David Roberts (5)

1 University of Washington, 4000 15th Ave NE, Seattle, WA 98195,, @CaitLittlef

2 University of Washington, 4000 15th Ave NE, Seattle, WA 98195,, @JL_Michalak

3 The Nature Conservancy, Fort Collins, CO,

4 University of Washington, 4000 15th Ave NE, Seattle, WA 98195,, @jjjlawler

5 Albert-Ludwigs-Universität, Tennenbacher Straße 4 Freiburg, Germany 79106,, @droxburgh

Climate change is already impacting the distributions of many terrestrial organisms. A major conservation concern is whether species will be able to move across human-dominated landscapes to track changes in climate.  Consequently, increasing the connectivity of landscapes is one of the most-often recommended adaptation strategies for protecting biodiversity in a changing climate. Here, we use the concept of analogous climates to trace routes through space that track current climates into the future in Western North America. Specifically, for a given location on the landscape, we identify all areas within a given dispersal distance that are projected to be climatically analogous in the future to the current climate in that focal location.  We define analogous climates based on the multivariate similarity between locations, with thresholds based on the average climatic breadths spanning the ranges of different species. Using connectivity tools based on electrical circuit theory (Circuitscape), we then evaluate the accessibility of climate destinations in light of landscape intactness (based on human population density, roads, and land- cover). These connectivity analyses highlight potential barriers to and, conversely, pinch-points in species movements for tracking suitable climate analogs into the future. Our results identify potential climate refugia and critical areas for movement in western North America to ensure that suitable climates in the future are within reach for a range of terrestrial plants and animals.