Itcha-Ilgachuz caribou in decline

While there are presently no plans to kill wolves in the Cariboo-Chilcotin region a research project is underway.

While there are presently no plans to kill wolves in the Cariboo-Chilcotin region a research project is underway to determine if wolf predation is impacting the Itcha-Ilgachuz mountain caribou.

“The latest aerial count shows an evident decline,” said Rodger Stewart, Cariboo Region manager for the Ministry of Forests, Lands and Natural Resource Operations. “We counted 1,350 caribou in work we did this past June.”

Earlier this month ecologist Dr. Scott McNay of Wildlife Infometrics in Mackenzie and a team of experts began examining the caribou population dynamics to assess the influence of predation on the Itcha-Igachuz caribou population.

The team will also study the element of wolves, Stewart told the Tribune, adding available data on wolves is too weak at this time to draw definitive conclusions about their influence.

“We’re seeking recommendations from the experts on cost-effective means to build knowledge about wolf density, pack sizes and pack distributions in critical caribou habitat,” he said.

The ministry will need that information, which is due at the end of March 2015, to determine whether predator management is justified and to what extent.

In 2007 ministry counts revealed 1,780 caribou in the Itcha-Ilgachuz herd, while back in the early 70s there were as few as 400.

During the 80s and 90s the numbers steadily increased, peaking in 2003 with 2,800 animals.

“At that time when the population was being examined by caribou experts in North America they considered that number to be at or near peak population target given the extent of the habitat that was there,” Stewart said.

June’s aerial count also showed that only eight to 10 per cent of the total population is calves, that adult female mortality is at 24 per cent and male mortality is about 15 per cent.

“It’s clear for the last decade we’ve had a negative influence on recruitment,” Stewart said, pointing out in the past the calf percentage didn’t go below 16 per cent and had gone as high as 24 calves per hundred cows.

Core high value habitat in the Itcha and Ilgachuz is protected by parks and wildlife habitat areas that were established by the Cariboo Chilcotin Land Use Management Plan, however, during the last few winters most of the habitat use has been outside of those areas, “ Stewart said.

“We also know the caribou are continuing to the use the stands that have been killed by mountain pine beetle,” he added.

Eastern caribou

Stewart said there are plans to count caribou in the eastern part of the Cariboo region this  coming March.

Since the death of wildlife biologist Randy Wright in 2012, who focused his efforts on the herd, there haven’t been the resources to continue his work, Stewart said.

Before Wright became ill, the wolf population had been reduced to less than five wolves per 1,000 square kilometres, a target that was expected to provide a foundation for recovery in that area.

“We had the habitat, we had reduced the disturbances and we had reduced the wolves,” Stewart said. “We have not had the resources to monitor the wolf pack since then.”

With the count, the ministry expects to determine if there are any influences despite having lost track of the wolf packs.

“There were 14 wolf packs that were preying on the caribou in that area,” Stewart recalled.

An external expert, Dr. Bob Hayes, who examined the work Wright was doing, concluded the work should continue because it would allow for examining the effect of predation reduction on caribou population dynamics.

“It’s just that we would never have secured the resources to be able to give that project the same kind of monitoring and treatment scenarios as what’s being done in the Kootenays and the Peace,” Stewart said.