Climate change may be changing amphibian evolution
Disruptions in global weather patterns may be forcing some species to adapt to new conditions or face extinction. Science Daily is reporting that research on some species of amphibians suggests that animals are being forced to alter their patterns of mating and producing young in order to keep up with rapidly changing conditions.
A study at the Smithsonian Tropical Research Institute looked at egg-laying habits of Panama’s pantless tree frog, or Dendropsophus ebraccatus. Some 6,000 species of frogs lay their eggs in water, but pantless tree frogs, like many tropical frogs, lay theirs on land in a life cycle that depends on Panama’s annual spring rains to function.
Justin Touchon of Smithsonian Tropical gathered rainfall data from the Panama Canal authority and found that regional rainfall amounts have been decreasing, as predicted by climate change models. The area now has fewer days of rain per year and larger gaps of dry days between storms.
Pantless tree frog eggs are particularly vulnerable to drying out. If more than a day passes with no rain, the embryos in the eggs begin to die. Touchon said that the frogs’ mating cycle is triggered by heavy rain, and without it, the species is producing fewer offspring on land.
“Pantless treefrogs can switch between laying eggs in water or on leaves, so they may weather the changes we are seeing in rainfall better than other species that have lost the ability to lay eggs in water,” Touchon told Science Daily. “Being flexible in where they put their eggs gives them more options and allows them to make decisions in a given habitat that will increase the survival of their offspring.”
Amphibians, because of their permeable skin, varied habitat both in and out of the water and the fact that they eat both plants and animals, were long considered to be the most sensitive organisms inhabiting their ecosystems. The amount of pollutants in a marsh, pond or river has generally been measured by the health of the location’s amphibians.
Newer studies reveal, however, that amphibians are quite adaptable and often very hardy in the face of environmental shifts. Now biologists tend to look at tiny, shelled aquatic animals called brachiopods, which are much more sensitive to the presence of environmental toxins.
The World Wildlife Foundation has reported that climate change could cause dramatic rises in extinctions and major displacement of native species in the decades to come.
[image of tree frog via Shutterstock]