Multidimensional diversity of bird communities across spatial variation of land cover in Zoige on the eastern Qinghai-Tibetan Plateau

Aichun Xu,Xiaoyi Wang,Jianfeng Yi,Chunlan Zhang,Chen Yang,Maojun Zhong,Ke Tang,Junhua Hu,Wei Liu,Haigen Xu

doi:10.1186/s40657-021-00259-4

Abstract

BackgroundSpatial variation of land cover can result in the changes of community similarities and biotic homogenization, whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance, and degenerate ecosystem services they offer. However, it remains scarce to integrate multidimensional diversity for unveiling how variations in land cover may influence the patterns and processes of biotic homogenization in the Anthropocene. In this study, we examined how spatial variation of land cover could alter taxonomic, phylogenetic and functional homogenization of bird communities simultaneously in a compound ecosystem of Zoige Marsh on the eastern Qinghai-Tibetan Plateau. Acting as the largest alpine marsh and peatland in the world, Zoige Marsh has undergone great changes in the land cover pattern due to climate change and anthropogenic activities.MethodsWe conducted transect surveys for bird communities over six years (2014‒2019) during breeding seasons in four main land cover types (meadow, woodland, village and marsh), representing the spatial variation of land covers in the study area. We compared multidimensional diversity (taxonomic, phylogenetic and functional diversity) among land covers to assess the effects of spatial variation in land cover type on bird communities, particularly whether this variation has homogenized biotic communities.ResultsBird communities during breeding seasons were different and complementary in the four land covers. Taxonomic, phylogenetic and functional similarities were significantly lower in meadow than in the other three types, i.e. woodland, village and marsh. However, when we controlled for the effects of taxonomic similarities, the pattern of phylogenetic similarities almost reversed, with the highest standardized effect size (SES) phylogenetic similarity in meadow; and we found no significant difference in SES functional similarity among land covers.ConclusionsOur results suggest that spatial variation of land cover can play a crucial role in regulating multiple dimensions of bird diversity in Zoige Marsh. The findings indicate that taxonomic, phylogenetic and functional homogenization of bird communities may differently response to the variation of land covers. It thus highlights not only the relative roles of different land covers in maintaining biodiversity and community structures of birds, but also the urgency of retarding ecosystem degradations on the eastern Qinghai-Tibetan Plateau.

Highlights

Spatial variation of land cover can result in the changes of community similarities and biotic homogenization, whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance, and degenerate ecosystem services they offer
Our results suggest that spatial variation of land cover can play a crucial role in regulating multiple dimensions of bird diversity in Zoige Marsh
The findings indicate that taxonomic, phylogenetic and functional homogenization of bird communities may differently response to the variation of land covers

Summary

Introduction

Spatial variation of land cover can result in the changes of community similarities and biotic homogenization, whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance, and degenerate ecosystem services they offer. Available resources are usually different among land cover types, and variations in land cover may cause the homogenization of available resources which would cause local extirpations and even extinction of specialized species (those requiring particular habitat or food resources), while be beneficial to environmental generalists (those with less selective habitat or dietary needs) (Olden et al 2004; de Castro Solar et al 2015) This homogenizes the biota and further leads to serious ecological and evolutionary consequences, and is a huge challenge for biodiversity conservation (Olden 2006; van der Plas et al 2016). Integrating taxonomic, phylogenetic and functional diversity can gain a more comprehensive understanding of how variations in land cover would influence the patterns and processes of biotic homogenization (Liang et al 2019; Weideman et al 2020). Even biotic homogenization can operate on multidimensional (e.g. taxonomic, phylogenetic and functional) diversity, the attempts to simultaneously assess how they respond to homogenization are relatively few (Liang et al 2019)

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Conclusion