Few escape routes available for climate change-driven migration

Few escape routes available for climate change-driven migration

Warming temperatures, rising oceans, and worsening storms are all effects of climate change that threaten our fragile habitats. Humans can, at least temporarily, adapt our homes by building flood walls or air conditioning units to withstand increasing temperatures, but the animals in our neighborhoods and beyond have only one reliable tactic to survive: move.

Mass migrations will become more commonplace across the world as animals seek higher latitudes or higher elevations to adapt to a warming Earth. The problem is that, while humans have highways and planes to escape dangerous coastlines, animals rely on unbroken habitat to make the trek to new areas. Such natural corridors that facilitate the movement of birds, amphibians, and mammals are in short supply in the U.S., where an estimated 49 percent of land is modified by human use.

A study led by Dr. Jenny L. McGuire of Georgia Tech and recently published in Proceedings of the National Academy of Sciences revealed that only 41 percent of land in the U.S. is connected enough to sustain migrating species.

The problem is particularly dire in the Eastern U.S., where only 2 percent of land has enough connectivity to facilitate movement. Dr. Brad McRae, a senior landscape ecologist at The Nature Conservancy and an author of the research said the East is full of “dead ends,” while the West offers more varied topography that animals can use to shift in elevation instead of location.

The routes that animals will need to use to make their migrations are complex, but Dan Majka, conservancy cartographer and analyst for The Nature Conservancy, has combined McGuire’s study with other migration data to produce a gorgeous, moving map of the migration patterns. The map underscores the importance of the Eastern U.S. in the mass migrations of the future, especially the Appalachian mountain range.

McRae said that improving broken corridors is a key way to protect biodiversity, for “shifting their ranges is one of the most important ways that species avoided extinction during past periods of climate change.”

Humans can help heal fragmented areas by removing infrastructure like fencing, rerouting infrastructure like pipelines and power lines, and adapting infrastructure like roadways by adding wildlife passes. Agricultural land can also be used to move animals that might typically avoid human-touched areas.

“Figuring out what kinds of landscape might be connected enough for species to move already and making sure we don’t fragment those further is one conservation strategy,” McRae said. “Another strategy can be to change our management practices and make working lands more friendly to species.”

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