مقاله انگلیسی رایگان در مورد مدل گزینش منبع یخ دریایی برای خرس های قطبی – وایلی 2017

Polar bears (Ursus maritimus) live in a highly variable, dynamic environment. The sea ice they rely on for hunting, resting and travelling changes daily, seasonally and annually (Falk-Petersen et al. 2000). While polar bears have evolved in the Arctic and are accustomed to high levels of environmental variability, they are currently experiencing dramatic long-term reductions in sea ice extent and volume (ice is thinner and younger), as well as a shorter duration of seasonal ice cover, that clearly exceeds the normal variability that characterizes the system (Laidre et al. 2015a, Stroeve et al. 2012). Climate models predict continued declines of sea ice across all months, and possibly an ice free Arctic occurring for the first time as early as in 2037 (Wang and Overland 2009). This is expected to have large negative consequences for polar bears across their range (Amstrup et al. 2008, Regehr et al. 2010, Stirling and Derocher 2012). Negative consequences on reproduction, condition and survival rates have already been reported in southern Beaufort Sea and western Hudson Bay subpopulations (Lunn et al. 2016, Regehr et al. 2010, Rode et al. 2014). These trends have been linked to habitat availability, habitat use and/or foraging ecology. Habitat selection has been investigated across several polar bear subpopulations, and a general model developed for the Arctic as a whole indicates a large decline in high quality polar bear habitat in the 21st century (Durner et al. 2009). However, sea ice conditions, oceanographic conditions, foraging conditions, human impacts and other ecologically relevant variables vary greatly regionally, so there is a need to develop more area specific habitat selection models for different subpopulations of polar bears, where such data are used for conservation purposes.