At the macroscale, climate strongly correlates with species richness gradients, resulting from differences in in-situ diversification and dispersal. One historical explanation for the pattern is that regions spanning temperate climates contain few species because past disturbances have generated high extinction rates, and species from tropical regions are unable to easily colonize temperate regions. We test these postulates for Himalayan plants, which span subtropical to temperate climates over steep elevational gradients.

中文翻译：

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冰冻线和扰动在驱动温带地区植物物种丰富度低的关键作用

在宏观尺度上，气候与物种丰富度梯度密切相关，这是由于就地多样化和扩散的差异造成的。对该模式的一种历史解释是，跨越温带气候的地区包含的物种很少，因为过去的干扰已经产生了很高的灭绝率，并且来自热带地区的物种无法轻易在温带地区定居。我们为喜马拉雅植物测试了这些假设，这些植物跨越陡峭的海拔梯度，跨越亚热带到温带气候。