来源 Taylor & Francis
美洲鼠兔(Ochotona princeps)是兔形目下的一种动物,主要生活在北美洲西部的群山之间。过去科学界认为鼠兔不能耐受高温,随着全球变暖导致的海拔等温线逐渐升高,适合鼠兔生活的山地环境的海拔越来越高,因此数量也越来越少。然而真实情况并不如此。
鼠兔生活在大盆地(Great Basin)地区。相关科学家探索该地区时曾发现这里的鼠兔栖息地比过去更热或者更干燥,并且已经没有了鼠兔的踪迹。因此科学家们推断鼠兔们可能已转移到更高的地区生活以躲避高温,或者甚至已经全部因为无法耐受高温而死亡,由此推断大盆地地区的鼠兔面临绝种的威胁。然而,相关研究主要关注该地区鼠兔传统的栖息地,并没有探索该地区边缘的区域或者拥有更适合鼠兔生存的环境的区域。
在 Taylor & Francis 出版旗下的 Arctic, Antarctic, and Alpine Research 期刊上发表的新论文中,作者们探索了包含了整个大盆地区域的四州地区(four-state region),记录了目前该地区内的鼠兔栖息地的位置和气候,其相关数据均未曾报道过。
该研究发现,与过去记录的栖息地数据相比,其实鼠兔可以在更大范围的温度和湿度条件下存活。其栖息地分布在可以从海拔5,350英尺到海拔13,000英尺以上,超过7,800英尺的海拔跨度,整个栖息地范围穿越了加利福尼亚州、俄勒冈州、内华达州和犹他州的40个山脉。
美国林务局太平洋西南研究站资深研究生态学家,该研究的主要作者 Connie Millar 说:“这些数据为理解大盆地区域中的鼠兔的生存状态提供了一个重要的新视角。因为鼠兔能在该地区持续生存,证明了它们能够忍受比既往所知更宽泛的地理和气候条件。”
Millar 和她的同事们重新审阅了2,387份鼠兔栖息地记录,发现有89个栖息地已经被鼠兔遗弃;774个栖息地中存在着比较古老的鼠兔生活的痕迹,但无法确认是否已经被鼠兔遗弃了,而这些栖息地的气候环境及海拔分布并无规律可循。
Millar 说:“气候条件并不能充分阐明哪些已经确认或者有待考证的被遗弃栖息地被遗弃的原因。这也就表明除气候条件外,还有其他因素同气候因素共同导致特定环境中的鼠兔种群数量的下降。发现非气候因素能够影响鼠兔种群数量可谓非常重要,因为它丰富了我们对鼠兔种群持续生存所需要的自然条件的认知,也让我们更好地了解其种群数量下降的原因。”
论文信息
标题 Distribution, climatic relationships, and status of American pikas (Ochotona princeps) in the Great Basin, USA
作者 Constance I. Millar, Diane L. Delany, Kimberly A. Hersey, Mackenzie R. Jeffress, Andrew T. Smith, K. Jane Van Gunst & Robert D. Westfall
Distribution, climatic relationships, and status of American pikas (Ochotona princeps) in the Great Basin, USA
期刊 Arctic, Antarctic, and Alpine Research
DOI: 10.1080/15230430.2018.1436296、
发表时间 Published online: 30 Apr 2018
摘要 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.
论文链接
http://www.tandfonline.com/doi/full/10.1080/15230430.2018.1436296?utm_source=WeChat&utm_medium=post&utm_campaign=JMO03726