Climate Change Models May Underestimate Extinctions

Mark Urban (uconn.edu)

Along with the rising temperature of the Earth, many scientists tried to find a solution, even predict future global warming. A number of climate models is made, then gives a conclusion. Conclusion is referred by several heads of state. However, due to not pay attention to a variable number of climate models conducted by scientists, the predicted extinction becomes inaccurate.

The new study shows that because climate models do not account for movement of species and competition, they too may underestimate the extinction in the future.

“We have really sophisticated meteorological models for predicting climate change,” says ecologist Mark Urban, the study’s lead author. “But in real life, animals move around, they compete, they parasitize each other, and they eat each other. The majority of our predictions don’t include these important interactions.”

Plenty of experimental studies have shown that species are already moving in response to climate change, says Urban, assistant professor of ecology and evolutionary biology at the University of Connecticut. For example, as temperatures rise over time, animals and plants that can’t take the heat are moving to higher altitudes where temperatures are cooler.

But not all species can disperse fast enough to get to these more suitable places before they die off, Urban says. And if they do make it to these better habitats, they may be outcompeted by the species that are already there – or the ones that got there first.

In view of the weakness, Josh Tewksbury and Kimberly Sheldon of the University of Washington created a mathematical model

that takes into account the varying rates of migration and the different intensities of competition seen in ecological communities. The goal was to predict just how successful species within these communities would be at shifting to completely new habitats.

From the model it is known that animals are able to adapt to climate change has a competitive advantage over animals that are unable to adapt. Animals that are in small areas, specific habitat requirements and the difficulty of spreading tends to extinction under climate change. These animals will very easily dominated by other animals that tolerate a wide habitas.

“When a species has a small range, it’s more likely to be outcompeted by others,” Urban says. “It’s not about how fast you can move, but how fast you move relative to your competitors.”

Urban likens this scenario to a train traveling up a mountain on a track. If each boxcar – representing a species – travels at the same speed, they will likely all reach the top eventually. But in reality, each car can move at a different speed, creating a collision course.

“There’s always a car in front of you and a car behind,” explains Urban. “When you introduce the ability to move at different speeds, they’re constantly bumping into one another, even running each other over. It’s a recipe for disaster.”

So very clearly, current predictions of biodiversity loss under climate change – many of which are used by conservation organizations and governments – could be vastly underestimating species extinctions.

Tropical communities, for example, which often have many species living in small areas, could be among the hardest hit by climate change. Urban says this is a first step toward making climate change predictions of biodiversity more sophisticated.

“This is a first step – to include in our models things that we know are true, like competition and dispersal,” says Urban. “Knowing these things, can we predict which species might be most at risk?”

Urban’s paper was published in the Jan. 4 online edition of the Proceedings of the Royal Society B: Biological Sciences. The work was funded by the National Science Foundation.

Source: http://today.uconn.edu/blog/2012/01/climate-change-models-may-underestimate-extinctions-says-uconn-biologist/