Dalerum Fredrik, Retief Tarryn Anne, Havemann Carl Peter, Chimimba Christian T, Janse van Rensburg Berndt
Research Unit of Biodiversity (UMIB, UO-PA-CSIC) University of Oviedo Mieres Spain.
Department of Zoology and Entomology, Mammal Research Institute (MRI) University of Pretoria Hatfield South Africa.
Ecol Evol. 2018 Dec 27;9(1):154-165. doi: 10.1002/ece3.4692. eCollection 2019 Jan.
Studies of biodiversity along environmental gradients provide information on how ecological communities change in response to biotic and abiotic factors. For instance, distance to water is associated with several factors that shape the structure and the functioning of ecosystems at a range of spatial scales. We investigated the influence of distance to a perennial water source on ant communities in a semi-arid savanna in northern Botswana. Ant abundance, taxonomic richness, and both alpha and beta diversity were generally higher during the wet than the dry season. However, there were strong seasonal influences on the effects of distance to water, with more pronounced effects during the wet season. While both abundance and beta diversity declined with increasing distances to water during the wet season, there was a contrasting increase in alpha diversity. There was no major effect of distance to water on taxonomic richness during either season. Beta diversity was as high across as along gradients, and we found support for modular rather than nested community structures along gradients. Our study demonstrated that small-scale gradients in distance to water can influence several aspects of ant communities in semi-arid savannas. However, our results also point to strong effects of small-scale environmental variation, for instance associated with vegetation characteristics, soil properties, and plant community structure that are not directly linked to water access.
对沿环境梯度的生物多样性研究提供了有关生态群落如何响应生物和非生物因素而变化的信息。例如，与水源的距离与一系列空间尺度上塑造生态系统结构和功能的几个因素相关。我们调查了博茨瓦纳北部半干旱稀树草原中与多年生水源的距离对蚂蚁群落的影响。蚂蚁的丰度、分类丰富度以及α和β多样性在雨季通常高于旱季。然而，与水源距离的影响存在强烈的季节效应，在雨季更为明显。虽然在雨季，随着与水源距离的增加，丰度和β多样性均下降，但α多样性却呈现相反的增加趋势。在两个季节中，与水源的距离对分类丰富度均无重大影响。β多样性在整个梯度上与沿梯度方向一样高，并且我们发现支持沿梯度方向的模块化而非嵌套式群落结构。我们的研究表明，与水源距离的小尺度梯度可以影响半干旱稀树草原中蚂蚁群落的几个方面。然而，我们的结果也指出了小尺度环境变化的强烈影响，例如与植被特征、土壤性质以及与获取水源无直接关联的植物群落结构相关的变化。
