Rethinking wildlife corridors in a changing climate

Black bears in British Columbia and Washington state will face habitat connectivity issues under future climate change scenarios, and the simple fix of creating north-to-south corridors may not be enough to buffer the animals from future climate change issues, according to recent research.

This is because some of these landscape corridors, such as low-lying valleys, may be too warm for the bears (Ursus americanus) to move through as parts of the earth warm up. And black bears are just one of a number of species that may need smarter planning when it comes to connecting suitable habitat under future climate change scenarios, researchers found.

“That’s one way that climate change could affect those current connectivity corridors,” said Julia Michalak, a research scientist in landscape ecology and conservation at the University of Washington and one of the co-authors of a review published recently in Frontiers in Ecology and the Environment on the ways that conservationists plan for connectivity under future climate change scenarios.

Many animals may be pushed out of their home ranges as the climate continues to shift. While often this means that animals will need to move northward or to higher elevations in pursuit of suitable temperatures and conditions, the different environmental characteristics of these areas complicate the problem, researchers noted. Some wildlife suited to specific wetlands, for example, may not find them to the north, and even they are available, wildlife may not be able to access them due to interspersed dry regions in between.

As a result, conservationists such as those with The Washington-British Columbia Transboundary Climate-Connectivity Project that works to connect species that have ranges on both sides of the border, are working to connect habitats as a buffer to future problems.

Yet most planning for connectivity focuses more on connecting animals to habitats within their current range, Michalak said, instead of planning to get species where they will need to be in the future because of changing climate. “If you want to facilitate these climate-driven range shifts, they’re not going to be necessarily the same,” she said.

The scientists looked at a number of different studies looking at how to meet the challenge of connecting species with future climate conditions and found they mostly divided into four major types of recommendations. The first category dealt with recommendations for connecting climates or climate conditions suitable for specific species. The second category took a more general approach to climate trajectories, focusing on the temperature thresholds of certain areas to mark suitable wildlife corridors.

The third included research that focused on environmental gradients, such as riparian corridors, that could serve as suitable routes for future range shifts. The final category looked at areas that have a high diversity of physical features and could host a greater diversity of species, even if those species change over time.

All of these different strategies had merit, Michalak said, but finding corridors that tick the boxes for more than one of these strategies will work the best for conserving species under future climate scenarios.

In general, climate corridors help move species up in elevation or toward the poles, but not always. We need climate connectivity research to help refine corridor locations, or identify specific corridor routes, and identify the exceptions, Michalak said.