Evolution May be Too Slow for Climate Change: Tropical Species in Danger

Can evolution keep up with climate change? That's a good question. As temperatures shift and regions change, species are becoming more and more vulnerable to climate impacts. Now, scientists have discovered that many vertebrate species would have to evolve about 10,000 times faster than they have in the past to adapt.

Species are adept at surviving in specific environments. Over hundreds, thousands and millions of years, they've grown to become suited to one location or another.

"Every species has a climactic niche which is the set of temperature and precipitation conditions in the area where it lives and where it can survive," said John J. Wiens, one of the researchers, in a news release. "For example, some species are found only in tropical areas, some only in cooler temperate areas, some live high in the mountains and some live in the deserts."

Unfortunately, climate change is altering these conditions. Wet areas are become drier, temperatures are warming and there are a host of other shifts that are occurring. In order to find out exactly how fast species might be able to adapt to these changing climates, researchers turned to phylogenies. These are essentially evolutionary family trees that show how species are related to each other based on genetic data. These phylogenies included 17 families representing the major living groups of terrestrial vertebrates, including frogs, salamanders, lizards, snakes, crocodilians, birds and mammals.

The researchers combined these "family" trees with data on the climactic niche of each species. They then estimated how quickly climactic niches evolved among species, using climactic data such as annual mean temperature. This allowed them to see how quickly species changed in the past and allowed them to estimate how quickly they would have to adapt in the future.

"We found that on average, species usually adapt to different climactic conditions at a rate of only about 1 degree Celsius per million years," said Wiens. "But if global temperatures are going to rise by about 4 degrees over the next hundred years as predicted by the Intergovernmental Panel of Climate Change, that is where you get a huge difference in rates."

In fact, the researchers compared the rates of change over time in the past to projections for climactic conditions in 2100. In most cases, it turns out that evolution rates for species would have to by different by about 10,000-fold or more.

"According to our data, almost all groups have at least some species that are potentially endangered, particularly tropical species," said Wiens.

The findings are important for understanding the impact that climate change could have on various species in the environment. It could also allow researchers to target conservation efforts, focusing on species that are most endangered by shifting temperatures.

The findings are published in the journal Ecology Letters.