Montane species are generally predicted to respond to climate change via upslope movement. Elevational range shifts of birds rarely have been examined in arid regions. Here, we examine shifts in the elevational distributions of breeding birds from two regions of the Great Basin, a desert in the western USA, over 10 to 20 years. We collected data annually from 2001 to 2020, a relatively long and consistent time series that is uncommon in research on distributional shifts. We used single-species occupancy models of 32 bird species to examine shifts along the full elevational gradient (1650–3200 m a.s.l.) and within the lowest and highest edges (25%) of the gradient. We then conducted simulations to test whether population stochasticity could confound inferences about shifts. We examined whether temperature, precipitation, and primary productivity (normalized difference vegetation index) were associated with occupancy and shifts. The elevational distributions of 23 species shifted, and simulations indicated that shifts in the distributions of 18 species were unlikely to be stochastic. The majority of shifts in the western Great Basin were downslope, whereas those in the central Great Basin were upslope. More shifts occurred at the edges of the elevational gradient than along the full gradient. Elevational shifts lacked a consistent climate-response signal, but those of some species appeared to follow changes in primary productivity. We found regional differences in elevational shifts and climate associations, and our work suggests that these desert bird populations may be relatively resilient to climate change.

中文翻译：

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干旱生态系统中山地鸟类海拔分布的变化


人们普遍预测山地物种会通过上坡运动来应对气候变化。在干旱地区很少研究鸟类的海拔变化。在这里，我们研究了美国西部沙漠大盆地两个地区繁殖鸟类海拔分布在 10 到 20 年间的变化。我们从 2001 年到 2020 年每年收集数据，这是一个相对较长且一致的时间序列，这在分布变化的研究中并不常见。我们使用 32 种鸟类的单物种占据模型来检查沿整个海拔梯度 (1650–3200 m asl) 以及梯度最低和最高边缘 (25%) 内的变化。然后，我们进行了模拟，以测试总体随机性是否会混淆有关变化的推论。我们研究了温度、降水和初级生产力（标准化差异植被指数）是否与占用和转移相关。 23 个物种的海拔分布发生了变化，模拟表明 18 个物种的分布变化不太可能是随机的。大盆地西部的大部分变化是下坡的，而大盆地中部的变化是上坡的。与沿整个梯度相比，在高程梯度边缘发生的偏移更多。海拔变化缺乏一致的气候响应信号，但某些物种的变化似乎遵循初级生产力的变化。我们发现海拔变化和气候关联存在区域差异，我们的工作表明这些沙漠鸟类种群对气候变化的适应能力可能相对较强。