Brief by Allen Best
Climate – August 2004 – Colorado Central Magazine
As the climate warms, vegetation will shift, and in response so will the mammals that depend upon that vegetation. Scientists report this is already happening, with species generally moving northward and breeding and flowering earlier in the year.
But what will happen eventually in the U.S. national parks? That picture was the goal of a study reported recently in Yale’s Journal of the School of Forestry & Environmental Studies. The researchers chose eight parks, from Acadia in Maine to Big Bend in Texas, but also including Yellowstone, Yosemite, and Glacier.
Scientists cautiously predict an influx of new species. “They’re moving northward and into parks,” said Oswald Schmitz, professor of population and community ecology. “But the species that were in the parks, especially in the northern parks, aren’t leaving those parks and going even farther north. So this migration crowds species much more. If you measure things only in terms of biodiversity, yes, it’ s going to be fantastic but we don’t know what affect the crowding will have.”
Schmitz used the analogy of human migration during the Great Depression, when waves of people fled to cities, putting pressure on social services, housing and jobs. If we have those same kinds of pressure in the parks, we’re going to see extinctions precipitated by these influxes,” he said. Even though biodiversity goes up for a while, eventually the pressure gets heavy. Mammals may distribute on the landscape, but it’s the interaction that ensues once these animals have redistributed that would lead to their ultimate demise.
The researchers also warn that the potential exists for the spread of Lyme and other animal-borne diseases into new areas.
“But that may be a conservative prediction,” says Schmitz. “Less predictable indirect effects of climate change could increase the toll beyond that found in this study … There’s no guarantee the ecosystem won’t simply collapse.”
While plants and animals have adapted to climate change before, the problem is the rate of change. “Animal and plant species don’t have enough evolutionary time to adapt,” he said.
The profound changes we are currently experiencing, he said, began only 150 or so years ago, with the dawn of the Industrial Age.
“People are not thinking about the world their grandchildren are going to inherit,” said Schmitz. “That’s the time scale we need to think about. When I talk about global warming to undergraduates, I tell them, ‘I will be dead long before CO2 fully doubles. But toward the end of your life you are going to realize that your children are going to be stuck right in the middle of this kind of environment.’ Their eyes bulge, because they realize their actions today really can have an impact on their future.”
