Altitudinal variation in butterfly community associated with climate and vegetation

Abstract Elevation creates a variety of physical conditions in a relatively short distance, which makes mountains suitable for studying the effects of climate change on biodiversity. We investigated the importance of climate and vegetation for the distribution of butterflies from 800 to 1400 m elevation. We sampled butterflies, and woody and rosette plants and measured air temperature and humidity, wind speed and gust, and solar radiation. We partitioned diversity to assess the processes underlying community shifts across altitudes – species loss versus replacement. We assessed the strength of the association among butterfly, vegetation, and climate. Butterfly richness and abundance decreased with altitude, and species composition changed along the elevation. Changes in butterfly composition with altitude were mainly through species replacement and by abundance increases in some species being compensated by decreases in others. Since the floristic diversity decreased with altitude due to soil conditions, and butterflies are closely related to their host plants, this could explain species replacement with altitude. Overall, we found a stronger association of butterfly community with vegetation than climate, but plant community and climate were also strongly associated between them. Butterfly richness was more strongly associated with plant richness than with temperature, while the reverse was true for butterfly abundance, which was more strongly associated with temperature than with plant richness. We must consider the complementary roles of resource and conditions in species distribution.摘要：海拔在相对较短的距离内即可造就多样的物理环境，这使得山地成为研究气候变化对生物多样性影响的理想研究系统。本研究针对海拔800至1400米区间内的蝴蝶分布，探究了气候与植被对其分布的重要性。我们对蝴蝶、木本植物以及莲座状植物（rosette plants）进行了采样，并同步测定了空气温湿度、风速与阵风以及太阳辐射量。我们通过拆分多样性组分，解析了沿海拔梯度的群落更替背后的核心过程——即物种丧失与物种替代两种模式，并评估了蝴蝶群落、植被与气候三者之间的关联强度。结果显示，蝴蝶物种丰富度与多度均随海拔升高而下降，且物种组成沿海拔梯度发生显著变化。沿海拔梯度的蝴蝶物种组成变化主要由物种替代驱动，部分物种的多度上升可通过其他物种的多度下降得到补偿。鉴于土壤条件导致植物区系多样性随海拔升高而下降，且蝴蝶与其寄主植物存在紧密的依存关系，这一机制可解释沿海拔梯度的物种替代现象。总体而言，我们发现蝴蝶群落与植被的关联强度高于其与气候的关联，但植物群落与气候之间同样存在显著的关联。蝴蝶物种丰富度与植物物种丰富度的关联强度高于其与气温的关联；而蝴蝶多度则呈现相反的模式，即其与气温的关联强度高于与植物物种丰富度的关联。在物种分布研究中，需同时考量资源与环境条件的互补作用。