- Research: Good pine nut years help bears. By Brodie Farquhar. Casper Star Tribune. With all the discussion on the blog about pine bark beetles, the importance of whitebark pine for grizzly bear nutrition and safety from human conflicts stands out.
- Whitebarks and grizzlies [and bear politics]. By Brodie Farquhar. Casper Star Tribune.
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Interesting arguments here; I was surprised by this quote in the first story:
“Chris Servheen, the grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service, counters that whitebark pine cone abundance is a poor predictor of conflicts, citing a poor statistical correlation.”
Contrast that assertion with this quote from a 2005 Interagency Grizzly Bear Study Team report:
“Significant loss of whitebark pine due to blister rust (Reinhart et al. 2001) or mountain pine beetle (Dendroctonus ponderosae; Haroldson et al. 2003) would reduce survival rates for bears, especially conflict-prone individuals. Should whitebark pine decline rapidly, we speculate we would witness a scenario similar to what occurred what dumps were closed in YNP; more management problems, particularly outside the RZ, with a substantial increase in measurable bear mortality (Haroldson et al. 2005:55).”
Hmmm.
Of course, Chris Servheen’s point about bears living in riskier habitats (places with more risk of bumping into people) is true:
“This means that bears that already live on the edge of the ecosystem in risky habitats have a higher risk of mortality even in good cone years, and those living in more secure habitats have lower risk of mortality even in poor years,” he added. “Where these animals live in relation to human activities is more responsible for mortality than whitebark pine cone abundance.”
However, it would appear that the health of the GYE grizzly population hinges on minor changes in the level of bear deaths. So, yes, they live in riskier habitats; and yes, more of those bears die in poor cone years. And the differences in survival between good and bad cone years apparently makes the difference between an increasing or declining population.
I don’t see the logic of acting like whitebark pine isn’t a key factor in that equation. It’s not like those bears starve to death without whitebark pine — it’s that they range further, at lower elevations, and are maybe even food stressed into taking more risks. So, yes, their proximity to people is important, but it’s lack of whitebark cones that pushes them over the edge.