Our first results are out!
Our research examining the effects of decreasing snowpack on snowshoe hares has been ongoing since summer 2009 and we are getting out our first results. We just published our first paper on this topic this week in the Proceedings of the National Academy of Sciences.
We conducted our research in western Montana near Seeley Lake across three extremely different snow years. We monitored over 140 hares weekly to quantify their coat color, snow cover around them and the degree of color mismatch between their coat and background colors. We found that hares have only limited ability to adjust the timing of their coat color molts to match their surroundings. We observed fixed start dates of both the fall and spring molts across the years, probably because the molts are largely regulated by daylength (photoperiod), and fixed rate of the fall brown to white molt. In contrast, hares were able to adjust to some degree the rate of their spring white to brown molt to match the immediate climate. For example in winter of 2011 which many of you might remember as an extremely long snow year, hares turned brown by about 16 days later than in the very short winter the previous year.
Next, we teamed up with climate scientists from the Department of Ecosystems and Conservation Sciences at the University of Montana Dr. Steve Running and his PhD student Jared Oyler to develop future snowpack models to predict the amount of color mismatch in the future. The snow models were downscaled to our study area and they averaged across 19 different climate models and across various scenarios of future climate change. The models predicted that compared to now, the average duration of snowpack will decrease by 29-35 days by mid-century and 40-69 days by the end of the century. Unless hares are able to evolve changes in the timing of their seasonal coat color molts, then over the next century the reduced snow duration will result in 4- to 8-fold increase in frequency of mismatched white hares on brown snowless background.