Distribution, climatic relationships, and status of American pikas (Ochotona princeps) in the Great Basin, USA

To advance understanding of the distribution, climatic relationships, and status of American pikas (Ochotona princeps) in the Great Basin, United States, we compiled 2,387 records of extant pika sites surveyed since 2005, 89 records of documented extirpated sites (resurvey of historic sites), and 774 records of sites with old sign only. Extant sites extended across five degrees latitude and ten degrees longitude, encompassed six subregions, traversed forty mountain ranges, spanned 2,378 m in elevation (1,631–4,009 m), and comprised three of five currently described pika subspecies. A climate envelope for extant sites using the PRISM climate model expands the range of temperature and precipitation values that have been previously described. Extirpated and old-sign sites were mostly found within the geographic and climatic space of extant sites, but often in warmer and drier portions. Considerable overlap of extirpated, old, and extant groups within the same climate space suggests that nonclimatic factors have also contributed to population losses. The broad distribution and enlarged climate envelope of extant pika sites indicate that despite some localized extirpations, pika populations are persisting across Great Basin mountains, and appear to be able to tolerate a broader set of habitat conditions than previously understood.

为深化对美国大盆地地区（美国）高原鼠兔（Ochotona princeps）分布、气候关系及现状的理解，本研究团队汇合了自2005年以来所调查的现存鼠兔栖息地记录共计2,387条，以及已记录的灭绝栖息地（历史遗址的复调查）记录89条，以及仅有旧迹的栖息地记录774条。现存栖息地横跨五度纬度与十度经度，覆盖六个次级区域，横穿四十座山脉，海拔跨度达2,378米（1,631至4,009米），包含目前描述的五种鼠兔亚种中的三种。运用PRISM气候模型构建的现存栖息地气候范围，拓展了先前描述的温度和降水量值范围。灭绝和仅有旧迹的栖息地大多位于现存栖息地的地理和气候区域内，但通常位于更为温暖和干燥的部分。同一气候空间内灭绝、旧迹及现存群体之间的显著重叠表明，非气候因素亦对种群减少产生了影响。现存鼠兔栖息地的广泛分布和气候范围的扩大表明，尽管存在局部灭绝，鼠兔种群在大盆地山脉中依然持续存在，并且似乎能够适应比先前所理解更为广泛的生境条件。