Climate change and habitat degradation are amongst the two greatest threats to biodiversity. Together, they can interact to harm species. However, how climate change and land-use change jointly affect the demographic vital rates that underpin population viability remains unknown. Here, using long-term data on birds from the increasingly degraded and rapidly warming Himalayas, we show that survival trends over time are linked to species' elevational ranges in primary, but not in selectively-logged forest. In primary forest, populations at their cold-edge elevational range limit show increases in survival rates over time, while those at their warm-edge elevational range limit suffer survival declines. This pattern is consistent with species tracking favourable climatic conditions over time, leading to improved demographic outcomes at progressively higher elevations with climate change, which in turn lead to upslope range shifts. In logged forest, however, survival rates remain relatively constant over time. This suggests that in response to climate change in the long term, individuals of the same species can maintain demographic vital rates in higher-elevation primary forest, but not in logged forest. This is the first demonstration of how two of the most disruptive anthropogenic influences on biodiversity interact to threaten survivorship in natural populations. Ignoring interactions between climate change and land-use change can potentially undermine accurate forecasting of the future of species in an increasingly warm and degraded world. Importantly, large tracts of well-protected primary forests across Earth's tropical elevational gradients may be essential to enable tropical montane species to persist in the face of climate change.

中文翻译：

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气候变化和土地利用变化对山地鸟类人口统计学的交互影响

气候变化和栖息地退化是生物多样性面临的两大威胁。它们可以共同作用以危害物种。然而，气候变化和土地利用变化如何共同影响支撑人口生存能力的人口生命率仍然未知。在这里，我们使用来自日益退化和迅速变暖的喜马拉雅山脉的鸟类的长期数据，表明随着时间的推移，生存趋势与原始物种的海拔范围有关，但与选择性采伐的森林无关。在原始森林中，处于冷边缘海拔范围限制的种群随着时间的推移显示出存活率的增加，而处于暖边缘海拔范围限制的种群则存活率下降。这种模式与物种随着时间的推移追踪有利的气候条件一致，随着气候变化，在逐渐升高的海拔处改善人口结果，这反过来又导致上坡范围的变化。然而，在被砍伐的森林中，存活率随时间保持相对稳定。这表明，从长期来看，为了应对气候变化，同一物种的个体可以在海拔较高的原始林中保持人口生命率，但在砍伐林中则不然。这是首次证明对生物多样性最具破坏性的两种人为影响如何相互作用以威胁自然种群的生存。在日益温暖和退化的世界中，忽视气候变化和土地利用变化之间的相互作用可能会破坏对物种未来的准确预测。重要的是，地球上大片受到良好保护的原始森林