Shedding Light on How, Why Climate Change Effects Animals
December 2, 2011

Shedding Light On How, Why Climate Change Effects Animals

An international team of scientists say that they have discovered a way to predict how environmental changes will affect gray wolves living in Yellowstone National Park.

The study, which is part of the Yellowstone Wolf Project, was published in the December 2 issue of the journal Science. The work was led by researchers at Imperial College London and also involved experts from the U.S. Department of the Interior, Utah State University and the University of California, according to a press release announcing the findings.

The researchers say that they have figured out how to anticipate how changes in the environment will impact the number, body size, genetics, and other biological traits of the wolves, using information collected from wolves living in the park from 1998 through 2009.

Some of the tracked characteristics, including the size of the population, are related to population ecology, the National Science Foundation (NSF) -- who partially funded the research -- said in a separate statement. Others, including the color of the animals' coats, are genetically determined via evolution.

The project, the NSF says, involved using a brand new model to compare data collected on the characteristics of Yellowstone wolves with that of annual environmental conditions. The research team defined conditions each 12-month period as either a "good year" (more favorable to the survival of the species) or as a "bad year" (less favorable).

"The novelty of the new model is that it looks at how the frequencies of changes in environmental conditions along the 'good to bad' year continuum simultaneously impact many wolf characteristics," lead author Tim Coulson, a professor at the Imperial College London Department of Life Sciences, said in a statement.

"We know that climate change is having an impact on the lives of animal species around the world. This is clear through the changes we've seen in their population sizes, as well as their body sizes, but what has not been so clear is what underlies these changes," he added. "This work provides a relatively easy way for biologists to investigate how, and why, environmental change impacts both the ecology and near term evolutionary future of species."

Coulson and his colleague determined that environmental changes would almost certainly cause both ecological and evolutionary responses in the gray wolves, but that any specific change could impact the wolves differently based on which part of their biology it affects, and that changes in the mean environmental condition would impact the Yellowstone wolf population size more than changes in the variability of environmental condition.

"For example," Imperial College London said, "suppose environmental conditions in a 'good year' helped increase the population size of Yellowstone wolves by increasing their survival rates. Also, suppose that a grey coat color would confer a survival advantage to wolves. Then, under those particular 'good' conditions, an increase in the size of the wolf population would be expected to produce an increase in the prevalence of grey coats among the wolves."

However, if certain types of environmental conditions in a period identified as a "good year" helped increase the wolf population size by increasing the availability of prey, it would likely not result in an increase of the prevalence of grey coast among the wolves, as the availability of prey and the color of the animals' coats are not directly related to each other.

Coulson and his colleagues believe that the techniques behind this study could ultimately be applied to other types of creatures, living in different types of ecosystems. Those other creatures could include insects or crop pests, or ultimately even be adapted to specific issues facing human beings, including the impact of obesity rate on survival and fertility rates, and ultimately the "resulting influence of those variables on the growth rate of selected human populations," according to Imperial College London.


Image Caption: Sibling members of Yellowstone National Park's Druid Peak Pack at play. Credit: Daniel Stahler/NPS


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