MOUNT VERNON — As climate change affects ecosystems, one species may benefit from its effects in the North Cascades.
A study published Feb. 6 found that the amount of high quality habitat for grizzly bears in the North Cascades will increase across all climate models, scenarios and time periods.
Jason Ransom, wildlife biologist with the North Cascades National Park Service Complex and co-author of the study, said even in the worst climate scenarios, “the high quality grizzly bear habitat actually increased over time through all of the models.”
The authors used a variety of models based on future greenhouse gas emissions and vegetation changes.
Meade Krosby, co-author and a senior scientist at Climate Impacts Group, said there are many climate responses possible, depending on the actions taken to reduce greenhouse gases.
“It’s important to try to look at that reasonable range of possible futures so that we are better able to respond to the range that’s out there,” Krosby said.
“We (can use) climate models like that all the time to understand how things will change so we can become more resilient to those changes — both people and nature.”
Climate Impacts Group works to support resource managers as they prepare for climate change.
The authors estimated that the increased habitat would increase the carrying capacity in the North Cascades from a baseline of 139 female bears to between 241 and 289 female bears.
Ransom emphasized that carrying capacity refers to how many bears the environment could support, not necessarily the number that will be present.
In general, climate change means more fires and higher intensity fires, which creates openings in the tree canopy. The first plants to grow back, including huckleberry, cow parsnip and horsetail, are often plants that grizzlies like to eat.
“When you look at that over time, even though there will be fires and things that seem sort of catastrophic in ecosystems … grizzly bears will adapt,” Ransom said.
Climate change also causes woody vegetation to move up in elevation in response to higher temperatures.
Ransom said that may be a good sign for human-grizzly interactions, since that would mean grizzlies will be drawn to areas farther away from populated areas.
“In the big picture, animals move back in as plants green back up, and (plant) succession starts again,” he said.
Grizzlies are generalists, which means they are adaptable and can eat different types of food depending on what’s available.
“In the winners and losers of climate change story, (grizzlies) are probably going to be winners, if they’re here,” Ransom said.
Krosby said the study is a rare silver lining to climate change impacts.
“We know that climate change is already affecting biodiversity, and it’s bad news for biodiversity on the whole, there’s no question about that,” she said.
“In this case, this is a bright spot in that it means that for the grizzly at least, for their habitat at least, this is some evidence that there’ll still be good habitat for them in the North Cascades, at least to the end of the century.”
As federal agencies prepare to release a draft plan this summer regarding bringing grizzly bears back to the North Cascades, Ransom said information about future habitat is necessary when making resource management decisions, and this study could inform later reintroductions.
