Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA.
CU Museum of Natural History, University of Colorado, Boulder, Colorado, 80309, USA.
Ecology. 2021 Apr;102(4):e03300. doi: 10.1002/ecy.3300. Epub 2021 Mar 18.
The largest and tallest mountain range in the contiguous United States, the Southern Rocky Mountains, has warmed considerably in the past several decades due to anthropogenic climate change. Herein we examine how 47 mammal elevational ranges (27 rodent and 4 shrew species) have changed from their historical distributions (1886-1979) to their contemporary distributions (post 2005) along 2,400-m elevational gradients in the Front Range and San Juan Mountains of Colorado. Historical elevational ranges were based on more than 4,580 georeferenced museum specimen and publication records. Contemporary elevational ranges were based on 7,444 records from systematic sampling efforts and museum specimen records. We constructed Bayesian models to estimate the probability a species was present, but undetected, due to undersampling at each 50-m elevational bin for each time period and mountain range. These models leveraged individual-level detection probabilities, the number and patchiness of detections across 50-m bands of elevation, and a decaying likelihood of presence from last known detections. We compared 95% likelihood elevational ranges between historical and contemporary time periods to detect directional change. Responses were variable as 26 mammal ranges changed upward, 6 did not change, 11 changed downward, and 4 were extirpated locally. The average range shift was 131 m upward, while exclusively montane species shifted upward more often (75%) and displayed larger average range shifts (346 m). The best predictors of upper limit and total directional change were species with higher maximum latitude in their geographic range, montane affiliation, and the study mountain was at the southern edge of their geographic range. Thus, mammals in the Southern Rocky Mountains serve as harbingers of more changes to come, particularly for montane, cold-adapted species in the southern portion of their ranges.
美国本土最大和最高的山脉——落矶山脉南部，由于人为气候变化，在过去几十年中显著变暖。在此，我们研究了 47 种哺乳动物的海拔分布范围（27 种啮齿动物和 4 种鼩鼱物种）是如何从历史分布（1886-1979 年）变化到当代分布（2005 年后）的，这些变化发生在科罗拉多州 Front Range 和 San Juan Mountains 的 2400 米海拔梯度上。历史海拔分布范围基于超过 4580 个经地理定位的博物馆标本和文献记录。当代海拔分布范围基于 7444 个来自系统抽样工作和博物馆标本记录的记录。我们构建了贝叶斯模型来估计物种由于在每个海拔 50 米间隔的抽样不足而存在但未被检测到的概率，这些模型利用了个体水平的检测概率、在海拔 50 米的垂直带内检测到的物种数量和斑块度，以及从最后一次已知检测到的存在概率的衰减。我们比较了历史和当代时期 95%的可能性海拔范围，以检测方向变化。由于在每个海拔 50 米间隔的抽样不足而存在但未被检测到的概率，这些模型利用了个体水平的检测概率、在海拔 50 米的垂直带内检测到的物种数量和斑块度，以及从最后一次已知检测到的存在概率的衰减。我们比较了历史和当代时期 95%的可能性海拔范围，以检测方向变化。响应是可变的，因为 26 种哺乳动物的范围向上移动，6 种没有变化，11 种向下移动，4 种在当地灭绝。平均范围变化向上移动了 131 米，而仅在山区的物种向上移动的频率更高（75%），并且平均范围变化更大（346 米）。上界和总方向变化的最佳预测因子是物种在其地理范围内的最大纬度较高、山地联系以及研究山脉位于其地理范围的南部边缘。因此，落矶山脉南部的哺乳动物是更多变化即将到来的先兆，特别是对其分布范围南部的高山、寒冷适应物种而言。
