Griz diet key to end of federal protection
Study due in fall should answer questions that kept a court from letting bear safeguards end.
By Mike Koshmrl, Jhnewsandguide.com
A study on the nuances of Yellowstone ecosystem grizzly
bear diets due this October will determine whether managers will recommend ending federal protections for the species, officials said last week. The study, called a food synthesis, will take a "holistic approach" to analyzing grizzly bear diets, said Frank van Manen, the team leader for the Interagency Grizzly Bear Study Team. Van Manen spoke from the Wort Hotel
on April 17, where carnivore managers were convening for the Yellowstone Ecosystem Subcommittee of the Interagency Grizzly Bear Committee's annual Jackson meeting.
"We felt like we couldn't just look at whitebark pine, because everything is interrelated," van Manen said. "We're basically looking at changing food dynamics — the changing availability of different food types. We're dealing with a very complex landscape. Whitebark pine, cutthroat trout ... there's a lot of ongoing changes."
That grizzlies are omnivores with very broad-based diets complicates matters.
A "very exhaustive literature review," van Manen said, identified 234 species of plants, animals and presumably fungi that the bears in the ecosystem have been known to consume. Some 75 of the species were found to be consumed "pretty frequently," he said.
Focus on whitebark pines
Central to the food synthesis is grizzlies' reliance on whitebark pines.
Grizzly bears have been listed as "threatened" under the Endangered Species Act for the past four years. Originally listed in the 1970s, they were delisted by the U.S. Department of the Interior in 2007, but the 9th Circuit Court of Appeals upheld a court-ordered reversal of the status change in 2009.
Chris Servheen, the U.S. Fish and Wildlife Service's grizzly bear recovery coordinator, said the court was ready to agree that grizzly populations are healthy if the question about declining whitebark pine is answered.
"The food synthesis is going to allow us to make an informed decision on that," he said. "At the end of the food synthesis process this fall -— if we decide that we can make a good case for the courts — then we will proceed on a new [delisting] rule in 2014."
Determining declines in whitebark pines, van Manen said, will use 12 years of NASA satellite data to measure the greenness of "thousands, probably millions" of 15-acre parcels. Whitebark pines have been in decline from years, largely due to infestations from the fungus blister rust and mountain pine beetles.
Do bears change as trees do?
During his presentation, van Manen walked the crowd through the analysis. He displayed an illustration of a 15-acre whitebark stand that was "moderately to heavily impacted" between 2007
and 2009.
"With this measure from the satellites of this vegetation index, we can pick up when that [decline] really occurred," he said. "This is just one small area. ... Imagine being able to do this for the entire ecosystem and you get a pretty good idea of where the biggest changes really occurred."
The other portion of the whitebark pine study investigates use by grizzly bears, which typically forage on seeds of the high-elevation conifer between Aug. 15 and Sept. 30.Are there changes in the selection of whitebark pine habitat over time?" van Manen asked. "In other words, do you see changes in a poor versus a good whitebark pine year?
"We're also looking at duration of time grizzly bears spend in whitebark pine stands," he said.
Monitoring of other important foods — such as ungulate carcasses and cutworm moths — has been bolstered and will be reviewed in a separate studies.
Landscape-level conclusions cannot be drawn at this point, van Manen said.
"We're still testing this," the study team leader said. "We have not applied it yet to the entire ecosystem. We're aching to do that."
This summer, van Manen said, the grizzly bear study team will begin writing the report. Each portion will be submitted as an academic article to a peer-reviewed journal.
No decision will be made on writing a delisting rule until the food synthesis is complete, Servheen said.
"That decision has not been made yet," he said, " and it will not be made until this fall."
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