JWM: Climate change may restrict salamanders’ range

Climate change could dramatically decrease the range of salamanders across the eastern United States and Canada, raising questions about how that might affect the ecosystems in which they play a fundamental role.

Most salamander species have tiny populations, which take advantage of micro-climates across small ranges. That specificity makes them particularly susceptible to climate change. But for a recent study, published in the Journal of Wildlife Management, researchers wanted to look at some of the most common salamanders on the continent—species that range from the Texas to Canada, or from the Great Lakes to Maine.

Even for some of these common species, they found, climate change could restrict their ranges significantly in the next 50 years. For the four-toed salamander, that could mean losing as much as 96% of its range.

“Understanding how these widespread species will be impacted by climate change will help us understand what may happen to small-ranging species,” said researcher Brian Widmer, who led the study as part of his master’s degree work at Central Michigan University.

Widmer’s team used computer modeling to learn how climate change may affect the climatic ranges of four species: the spotted salamander (Ambystoma maculatum), blue-spotted salamander (A. laterale), four-toed salamander (Hemidactylium scutatum), and red-backed salamander (Plethodon cinereus).

Looking at data collected from museums, research organizations and citizen scientists to see where these salamanders occurred and what conditions they preferred, the researchers created maps that showed preferable climate conditions currently and into 2070 under both conservative and more extreme predictions of greenhouse gases.

While the four-toed salamander will see the greatest loss of suitable range, researchers found, just a quarter of spotted salamanders’ range will maintain suitable conditions. Red-backed salamanders will see their suitable range cut by more than a third. The models suggested blue-spotted salamanders wouldn’t be affected by climate change, but researchers believe the result is due to poor data.

Amphibians are already experiencing mass extinctions. Climate change could increase those declines, researcher warned.

“We can’t say as soon as 2050 hits that these species will disappear,” Widmer said, “but we can say the climate factors that we included will make it harder for them.”

Under greater stress, the salamanders become more susceptible to threats like disease or land use changes that they could otherwise survive, raising the risk of extinction.

“One little nick in their armor and they’re gone,” he said. “Their numbers start decreasing quicker.”

And unlike birds or mammals that might be able seek out better conditions in a warming world, salamanders can’t make the same kind of migration. Four-toed salamanders, for example, rely on ephemeral ponds, where they lay their eggs on the edge. If a dry spell eliminates those ponds, Widmer said, those eggs are gone.

“That’s partly why we believe the four-toed salamander was hit hardest in terms of climate change,” he said.

If these species disappeared throughout the range, it could dramatically alter the ecosystem, Widmer said. Salamanders play important roles as both insect predators and prey for other species. While they’re often missed by hikers, Widmer said, they can occur at large densities, making them a valuable part of other birds’ and mammals’ diets and a critical part of the food web.

“Not only are they regulating a huge population of insects by preying upon them,” he said. “They’re also being preyed upon.”

This article features research that was published in a TWS peer-reviewed journal. Individual online access to all TWS journal articles is a benefit of membership. Join TWS now to read the latest in wildlife research.