Faced with an uncertain future, wildlife managers say the best thing they can do to preserve species in the face of climate change is to protect and enhance large expanses of habitat that will give animals a chance to adapt.
But it’s more than just making sure particular places remain viable. More important may be giving animals the pathways to move between blocks of wild country like central Idaho wilderness areas and Yellowstone and Glacier national parks in Montana.
For example, as the climate warms, wildlife and forest managers expect high-elevation white bark pine communities to continue to decline. The nuts in white bark pinecones are an important seasonal food source for grizzly bears. Warming temperatures allow mountain pine beetles to thrive and move into the mountain tops that are home to the twisted and gnarled trees.
“If over time those climate issues cause white bark pine habitat to shrink in the greater Yellowstone (area) then the bears are going to need an avenue to get north,” said David Hopper, a wildlife biologist with the U.S. Fish and Wildlife Service at Boise.
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Hopper said management actions like targeted road closures could make it easier for the bears to move across the spine of mountain ranges in Idaho, Montana and Wyoming as they search for new food sources.
“Connectivity is the single biggest or most appropriate thing we can do collectively,” said Sean Finn, science coordinator for the U.S. Fish and Wildlife Service’s Northern Rockies Landscape Conservation Group at Boise.
Gregg Servheen of the Idaho Department of Fish and Game said just as important is continued monitoring of climate change and its effects on individual species. He said many of the models that attempt to predict how the climate will change are done at a large scale that doesn’t easily translate to the needs of a particular species in a particular place.
“We know we are going to see temperatures increase over time and changes in precipitation,” he said. “The question is how do we get that information such that it helps us determine how it’s going to affect our habitats and build that into adaptive management for our species?”
For example, he said there is a general understanding that as temperatures climb, the habitat for high-elevation species like wolverines is going to shrink.
“What is that going to do for connectivity between populations?” he said. “If we have less snowpack, is that going to concentrate the kind of (human) recreation in places that wolverine are trying to make their living?”
For many species, Servheen said, wildlife managers know what they need based on their historic range, where they move seasonally and the types of habitat they seek out. But that information might be less valuable as the warming climate changes forests and grasslands.
“You have to make some assumptions about how vulnerable the species is,” said Leona Svancara, an Idaho Fish and Game ecologist at Moscow. “That includes how sensitive they are to climate change as well as how much of an exposure they are going to get. The other piece of it is how much they adapt, their adaptive capacity, can they move? Physiologically, can they handle the larger range of temperature? For a lot of species, we just don’t know enough.”
She said they do know some species already in decline are likely to continue to have problems. Amphibians, for example, are suffering from a loss of wetlands, reduced stream flows and higher water temperatures.
“Will they still be able to persist on smaller habitat patches? For a lot of that we don’t know. We try to make assumptions. We try to piece together small pieces of the story to make a big picture.”
Sage grouse’s uncertain future
Idaho and the other Western states that are home to the threatened sage grouse have been working to help bolster their populations, hoping to avoid a federal listing of the birds as endangered that could be devastating to ranching, mining and other industries. This year the federal government opted not to list the birds, but the government’s new rules angered some of the states. Idaho is suing to block the rules.
Researchers say climate change is worsening some of the trends that are making it harder for the grouse to survive in its native sagebrush rangeland.
While the direct impact of climate change on sage grouse is unknown, a number of studies have predicted that it will harm the bird’s habitat. For example, a U.S. Geological Survey study of sagebrush habitat in Wyoming, published in April, analyzed 30 years of climate data and concluded climate change would significantly reduce the amount of sage grouse habitat by reducing precipitation, creating conditions more favorable to plants other than sagebrush and making the habitat more vulnerable to fire, insects, disease and invasive species.
Cheatgrass, an invasive grass that has contributed to worsening wildfires that destroy the sagebrush on which the birds depend, will do better as the steppe gets hotter and drier and carbon dioxide levels increase, said John Robison of the Idaho Conservation League.
“Sage grouse is kind of an indicator species,” he said.
Nathan Brown, Times-News