Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa.
Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, Cape Town, South Africa.
Sci Rep. 2020 Aug 6;10(1):13268. doi: 10.1038/s41598-020-70055-5.
Mountains influence species distribution through differing climate variables associated with increasing elevation. These factors determine species niche ranges and phenology. Although the distribution patterns of some specific insect groups relative to elevation have been determined, how differing environmental conditions across elevation zones differentially influence the phenology of various insect groups is largely unknown. This is important in this era of rapid climate change. We assess here how species composition and seasonal peaks in abundance among different insect pollinator groups and flowering plants differ across four floristically distinct elevation zones up a sentinel mountain subject to strong weather events. We sampled insect pollinators in four major groups (bees, wasps, beetles and flies) over two spring seasons. Pollinator species composition across all elevation zones tracks flowering plant species composition. In terms of abundance, beetles were the dominant group across the three lower zones, but declined greatly in the summit zone, where flies and bees were more abundant. Bee abundance peaked earlier than the other groups across all four elevation zones, where there were significant peaks in abundance. Bee abundance peaked earlier than flowering plants at the middle zone and slightly later than flowering plants at the base zone, suggesting a mismatch. We conclude that, while elevation shapes species distribution, it also differentially influences species phenology. This may be of great significance in long-term assessment of species distribution in sensitive mountain ecosystems.
山脉通过与海拔升高相关的不同气候变量来影响物种分布。这些因素决定了物种的生态位范围和物候。虽然已经确定了一些特定昆虫类群相对于海拔的分布模式，但不同海拔带的不同环境条件如何对各种昆虫类群的物候产生不同的影响在很大程度上是未知的。在这个快速气候变化的时代，这一点很重要。我们在这里评估了在受强烈天气事件影响的哨兵山上，四个具有不同植物区系的海拔带中，不同昆虫传粉者群体和开花植物的物种组成和丰度季节性峰值有何不同。我们在两个春季季节中对四个主要昆虫传粉者群体（蜜蜂、黄蜂、甲虫和苍蝇）进行了采样。所有海拔带的传粉者物种组成都与开花植物物种组成相吻合。就丰度而言，甲虫在三个较低的带中占主导地位，但在山顶带中大量减少，那里苍蝇和蜜蜂更丰富。在所有四个海拔带中，蜜蜂的丰度比其他群体更早达到峰值，并且在丰度上存在显著的峰值。蜜蜂的丰度在中间带比开花植物更早达到峰值，而在底部带比开花植物稍晚达到峰值，表明存在不匹配。我们的结论是，虽然海拔塑造了物种分布，但它也对物种物候产生了不同的影响。这在对敏感山地生态系统中物种分布的长期评估中可能具有重要意义。
