Drought, heat put stress on huckleberry plants, grizzlies - and human pickers

Despite scattered showers over the past month, Northwest Montana’s huckleberry crop is feeling the effects of a notably dry, hot year that kicked off with a dismal snowpack followed by a record-breaking drought and heat wave.

“With the drought and heat we’ve had, it’s really stressed the plants, so we’re seeing [berries] about three weeks to a month ahead of time,” said Chantelle Delay, a botanist for the Flathead National Forest. “It’s a response to stress. They need to reproduce, so they’ll put all their energy into reproduction.”

Huckleberries prefer relatively open, drier areas on south- and west-facing mountain slopes. But they still rely on water from the normally wet spring months.

The hottest June in history was accompanied by a 33-day stretch that month and early July with no measurable precipitation in the Flathead Valley.

Gretchen Gates, whose family has operated Eva Gates Homemade Preserves in Bigfork since 1949, said she is starting to get concerned about the effects a poor berry crop could have on business, and she’s paying more for huckleberries this year than at any point in the family-owned company’s history.

“I’m hoping the higher elevations will have more,” Gates said. “There didn’t seem to be much lower berries, and nobody knows whether it was the late frost this spring or how hot it was in June, but the lower berries just weren’t there.”

The berry pickers who sell her their harvests are working the slopes at 5,000 feet, which she said is a relatively high elevation for huckleberries at this time in the year.

People aren’t the only ones coming up short at their favorite berry patches.

This time of year, huckleberries normally make a favorite meal for grizzly and black bears, said Chris Servheen, a professor of wildlife conservation at the University of Montana.

“Bears will tend to move around more, looking for alternative foods, and movement usually increases conflicts,” Servheen said, but noted that he hasn’t seen a significant amount of human-bear conflicts so far this year. “It’s pretty quiet on the west side. That’s where you’d expect to find most of the huckleberry-concentrated bears.”

Even with a poor berry crop, however, Servheen said grizzly diets can include hundreds of different foods, so the bears still have plenty of options available. While huckleberries can provide an easy source of calories as the bears begin to fatten up for their winter sleep, they will also find roots, tubers, moths, ants, hornet nests and a variety of other berries such as those from hawthorn and mountain ash.

“They’re very adaptable and able to switch from one food to another,” Servheen said. “If a bear doesn’t get a lot of fat, they’ll just stay out later and tend to be more active later in the fall. They go into hyperphagia — which translates to ‘overeating’ — so they can gain more weight to go into their sleep.”

Tim Manley, a grizzly bear expert with Montana Fish, Wildlife and Parks, said bears typically switch to huckleberries in mid-July after spending June dining on buffalo berries and cow parsnip. He also has noticed an underwhelming huckleberry crop at lower elevations, but the poor yield has not correlated with an unusual number of grizzly interactions reported to him.

“We’ve been very quiet bear-wise,” Manley said. “I have gotten hardly any calls on them, so they’re finding something to eat, obviously.”

As far as the chokecherry and serviceberry crops, two other seasonal favorites for bears, he has gotten mixed reports.

“I imagine around lakes where there’s serviceberries growing, they might be pretty good. We’ve had that happen in dry years before.”

Since huckleberries tend to ripen later at higher elevations, Manley said, the grizzlies will usually ascend with the evolving crop. In normal years, the highest-elevation berries reach their peak in September, so he expects there’s still time for grizzlies to augment their diets with the popular fruit.

The relationships between weather, environment, huckleberry crops and bear ecology are still poorly understood, but experts in the area hope to change that.

U.S. Geological Survey ecologist Tabitha Graves is running a pilot project in Glacier National Park to learn more about the huckleberry supply in the Northern Continental Divide Ecosystem.

She’s hoping to eventually accumulate enough data to make accurate predictions for huckleberry crops based on weather patterns and location. She then plans to map that information to make predictions of how conditions in certain areas in a given year might affect wildlife such as bears.

“Earlier studies looked at spatial characteristics and weather characteristics, but they didn’t look at these both together,” she said. “That’s what I think will be crucial to understanding the complexity of the system.”

That type of prediction could also be useful for wildlife officials trying to reduce the number of interactions between bears and people.

“Bears tend to move around more when a particular food source isn’t as abundant,” she said. “If we can make this predictive map, it will help managers know what potential impacts there will be that year for different wildlife populations.”

Graves’ research in the park is similar to Wayne Kasworm’s work in the Cabinet-Yaak Ecosystem, where the U.S. Fish and Wildlife biologist has maintained berry sampling sites in the relatively tiny grizzly bear habitat for 24 years.

“I have sites where I go measure huckleberry production to get an indexed production,” Kasworm said. “This [year] doesn’t look so good, but it’s spotty and it’s still early.”

The Cabinet-Yaak grizzly population contains just a quarter of the acreage and 1/20th of the grizzly population found in the Northern Continental Divide Ecosystem, which includes Glacier National Park, the Bob Marshall Wilderness and the Rocky Mountain Front.

A slack berry crop could be particularly rough on the Cabinet-Yaak grizzlies. DNA studies from the bears’ hair samples have used isotope analysis to show they tend to be more vegetarian than grizzlies to the east.

“Our sample sizes are smaller over here, but for individual bears, we see numbers that vary from 5 to 20 percent of the diets of individual bears that are related to meat or animal matter. On the Northern Continental Divide that’s much higher,” Kasworm said. “We’ve got less big game, less sources of meat for bears than in other areas.”

Reporter Samuel Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.