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closeWolverine denning relative to snow depth and presence
Posted by jcopeland on 16 Sep 2014 at 17:20 GMT
This paper is certainly refines our understanding of snow persistence in the face of a warming climate. However, considering April 1 snow as representative of wolverine denning habitat is inconsistent with our understanding of wolverine snow-denning and the implications of climate warming. Averaging the dates of the denning period assumes the importance of snowpack for successful denning is equal throughout the denning process. Copeland et al. (2010) argued that the importance of a warming climate to the wolverine relates specifically to a potential loss of persistent snow, and therefore den site security, at the end of the denning period. The idea that the wolverine may be vulnerable to a warming climate relates to the fact that the later stages of reproductive denning align with the timing of spring snow melt. As snow melt occurs earlier due to climate warming, wolverine denning habitat erodes earlier as well thereby reducing denning habitat availability. As such, the availability of persistent snow on April 1 is much less important to a denning female wolverine than it is on May 15. This paper would have been much more informative had the authors focused their analysis on the latter portion of the denning period.
RE: Wolverine denning relative to snow depth and presence
jacurtis-496 replied to jcopeland on 29 Sep 2014 at 18:08 GMT
Thank you for your interest and comments. The primary purpose of this paper was to investigate the impact of cold-air pooling on snowpack persistence. We necessarily made assumptions regarding the links between wolverine reproductive ecology and snowpack to show an example ecological application. Our assumptions do differ from Copeland et al. (2010) in three important ways. First, as you noted, we examined an earlier date, which would tend to increase the predicted areal extent of suitable snow habitat. Second, we considered snow depth, using a snow-water equivalent of 400 mm (~1 meter of snow) rather than snow cover, this conservative threshold would tend to reduce the areal extent of suitable habitat. Finally, we examined snow pack on a finer scale (270 sq. m vs. 500 sq. m) and incorporated cold-air pooling (CAP) which tends to increase snowpack persistence in CAP-prone areas. A companion paper (Hudgens et al. currently in review) investigates wolverine habitat suitability and fecundity throughout the Sierra Nevada Ecoregion in greater detail and compares the results with Copeland et al. (2010).