Ice-age reptile extinctions shed light on responses to climate change

WASHINGTON - Researchers at the University of Michigan have found that a wave of reptile extinctions on the Greek islands over the past 15,000 years may shed light on how plants and animals will respond to human-caused climate change.

The Greek island extinctions also highlighted the critical importance of preserving habitat corridors that will enable plants and animals to migrate in response to climate change, thereby maximizing their chances of survival.

As the climate warmed at the tail end of the last ice age, sea levels rose and formed scores of Aegean islands that had formerly been part of the Greek mainland.

To gain a clearer understanding of the past consequences of climate change, Johannes Foufopoulos and his colleagues calculated the population extinction rates of 35 reptile species-assorted lizards, snakes and turtles-from 87 Greek islands in the northeast Mediterranean Sea.

The calculated extinction rates were based on the modern-day presence or absence of each species on islands that were connected to the mainland during the last ice age.

Foufopoulos and his colleagues found a striking pattern to the island extinctions. In most cases, reptile populations disappeared on the smallest islands first-the places where the habitat choices were most limited.

Especially hard hit were “habitat specialist” reptiles that required a narrow range of environmental conditions to survive. In addition, northern-dwelling species that required cool, moist conditions showed some of the highest extinction rates.

The researchers concluded that a similar pattern of extinctions will emerge at various spots across the globe as the climate warms in the coming decades and centuries. In addition to adapting to a changing climate, plants and animals will be forced to traverse an increasingly fragmented natural landscape.

“The widespread fragmentation of natural habitats greatly exacerbates the effects of climate change and undermines the ability of species to adapt to the new conditions,” said Foufopoulos.

“The lessons learned from the wave of reptile extinctions suggest that if species are to survive the global climate shift already underway, not only do humans have to set significantly more land aside for conservation, but these protected areas will also need to be connected through a network of habitat corridors that allow species migration,” he added.

The study appeared in the journal American Naturalist. (ANI)