Local-scale determinants of arboreal spider beta diversity in a temperate forest: roles of tree architecture, spatial distance, and dispersal capacity.

Qiongdao Zhang,Wei Shi,Hua Wu,Dong He,Cong Chen

doi:10.7717/peerj.5596

Qiongdao Zhang, Wei Shi + Show 3 more

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https://doi.org/10.7717/peerj.5596

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Abstract

Spiders are a functionally important taxon in forest ecosystems, but the determinants of arboreal spider beta diversity are poorly understood at the local scale. We examined spider assemblages in 324 European beech (Fagus sylvatica) trees of varying sizes across three forest stands in Würzburg (Germany) to disentangle the roles of tree architecture, spatial distance, and dispersal capacity on spider turnover across individual trees. A large proportion of tree pairs (66%) showed higher compositional dissimilarity in spider assemblages than expected by chance, suggesting prominent roles of habitat specialization and/or dispersal limitation. Trees with higher dissimilarity in DBH and canopy volume, and to a lesser extent in foliage cover, supported more dissimilar spider assemblages, suggesting that tree architecture comprised a relevant environmental gradient of sorting spider species. Variation partitioning revealed that 28.4% of the variation in beta diversity was jointly explained by tree architecture, spatial distance (measured by principal coordinates of neighbor matrices) and dispersal capacity (quantified by ballooning propensity). Among these, dispersal capacity accounted for a comparable proportion as spatial distance did (6.8% vs. 5.9%). Beta diversity did not significantly differ between high- and low-vagility groups, but beta diversity in species with high vagility was more strongly determined by spatially structured environmental variation. Altogether, both niche specialization, along the environmental gradient defined by tree architecture, and dispersal limitation are responsible for structuring arboreal spider assemblages. High dispersal capacity of spiders appears to reinforce the role of niche-related processes.

Highlights

Beta diversity, defined as the compositional dissimilarity between species assemblages, is an important component of biodiversity (Whittaker, 1960; Anderson et al, 2011)
Our results showed that a combination of tree architecture, spatial distance and dispersal capacity explained a considerable proportion of the variation in beta diversity, and these three components represented a comparable proportion to each other
Our results indicate that dispersal capacity plays a role in shaping beta diversity as spatial distance, suggesting that both of these factors should be considered when evaluating the importance of dispersal limitation

Summary

Introduction

Beta diversity, defined as the compositional dissimilarity between species assemblages, is an important component of biodiversity (Whittaker, 1960; Anderson et al, 2011). How to cite this article Zhang et al (2018), Local-scale determinants of arboreal spider beta diversity in a temperate forest: roles of tree architecture, spatial distance, and dispersal capacity. Beta diversity studies have been largely biased towards plants and birds (Socolar et al, 2016), whereas spiders, another functionally important taxon, have been relatively less studied in this respect (Carvalho et al, 2011; Rodriguez-Artigas, Ballester & Corronca, 2016). Previous studies have suggested that environmental heterogeneity, spatial distance and/or dispersal capacity differences can be relevant for beta diversity in general (Jiménez-Valverde et al, 2010; Carvalho et al, 2011; Rodriguez-Artigas, Ballester & Corronca, 2016). The influence of these factors on beta diversity of arboreal spiders is still unclear

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