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Posted by Balllpark Frank (66.58.236.31) on 11:03:19 02/14/13
In Reply to: Ever wonder what happended to all the moose? posted by albee
albee,
Thanks for posting this.
I am not surprised that wolves are taking moose in that area, although the overall number, spread over multiple winters, are not large enough to implicate wolves as the primary source of the population decline.
Based on my personal observations of winter moose population, the decline started prior to wolf reintroduction. That dovetails with documented (and personally observed) fact that the Yellowstone moose population declined drastically and rapidly after the 1988 Fires.
I have been told multiple times by multiple wildlife management workers and students that size and quality of winter range is the key determinant in the overall size of a wildlife population (excluding other sources of mortality, like predation, road kill, and kidnapping by alien spacecraft). The 1988 Fires in Yellowstone did a disproportionate "number" on the higher elevation spruce/fir forest, which moose prefer as winter habitat. Wolf reintroduction began in 1995, and by then, the moose population in Yellowstone had dropped precipitously.
The Tetons appear to be somewhat different, in terms of moose behavior. Historically, one would find large numbers of moose, in mid-winter, clustered in the valley bottoms along the rivers. It is likely that the rich abundance of willow groves might function as a preferred winter range. At the same time, I know that the Tetons have experienced quite a bit of wildland fire in the past several decades, which likely would impact the abundance of spruce/fir forest. Pulling these multivariate factors apart would keep some biostatisticians busy for quite some time.
Speaking of multivariate analysis, here's an additional factor. The success of the Yellowstone Grizzly Recovery Plan resulted in grizzlies slowly recolonizing the Teton area over time.
Obviously, the convergence of all these factors (as well as increased visitation/recreational use by humans) has worked a hardship on the moose population.
As long as I'm engaging in haphazard unscientific speculation, let's throw in whatever influence global warming might have in this scenario. There is so much we don't know, and are still learning, about the impacts. If, for example, increasingly warmer, longer summers keep shrinking glaciers and snowfields, might that result in a decrease in wetlands, favored summer habitat for moose.
OK, that's enough unscientific speculation for now. If nothing else, I hoped to showcase how complex this wildlife demographic business is.
Ballpark
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