Human-Induced Landscape Changes Homogenize Atlantic Forest Bird Assemblages through Nested Species Loss.

Marcelo Alejandro Villegas Vallejos,André Andrian Padial,Jean Ricardo Simões Vitule,Judi Hewitt

doi:10.1371/journal.pone.0147058

Marcelo Alejandro Villegas Vallejos, André Andrian Padial + Show 2 more

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https://doi.org/10.1371/journal.pone.0147058

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Abstract

The increasing number of quantitative assessments of homogenization using citizen science data is particularly important in the Neotropics, given its high biodiversity and ecological peculiarity, and whose communities may react differently to landscape changes. We looked for evidence of taxonomic homogenization in terrestrial birds by investigating patterns of beta diversity along a gradient of human-altered landscapes (HAL), trying to identify species associated with this process. We analyzed bird data from 87 sites sampled in a citizen science program in the south Brazilian Atlantic Forest. Regional-scale taxonomic homogenization was assessed by comparing beta diversity among sites in different HALs (natural, rural or urban landscapes) accounting for variation derived from geographical distance and zoogeographical affinities by georeferencing sites and determining their position in a phytogeographical domain. Beta diversity was calculated by multivariate dispersion and by testing compositional changes due to turnover and nestedness among HALs and phytogeographical domains. Finally, we assessed which species were typical for each group using indicator species analysis. Bird homogenization was indicated by decreases in beta diversity following landscape changes. Beta diversity of rural sites was roughly half that of natural habitats, while urban sites held less than 10% of the natural areas’ beta diversity. Species composition analysis revealed that the turnover component was important in differentiating sites depending on HAL and phytogeography; the nestedness component was important among HALs, where directional species loss is maintained even considering effects of sampling effort. A similar result was obtained among phytogeographical domains, indicating nested-pattern dissimilarity among compositions of overlapping communities. As expected, a few native generalists and non-native urban specialists were characteristic of rural and urban sites. We generated strong evidence that taxonomic homogenization occurs in the south Brazilian Atlantic Forest as a result of a directional and nested species loss, with the resultant assemblages composed of few disturbance-tolerant birds.

Highlights

Landscape changes due to human activities are the main cause of the recent biodiversity crisis [1], [2], [3]; the scale and magnitude of these changes has created a matrix of human-altered biomes, the so called anthromes of the Anthropocene [4]
We found consistent differences in beta diversity between humanaltered landscapes (HAL) categories (Fig 2; distance to centroid between groups ANOVA F = 47.45, P < 0.0001): natural sites have higher beta diversity than rural sites (P = 0.001), and urban bird faunas proved to be the most homogeneous category (P = 0.001)
Beta diversity of rural sites was roughly half of the beta diversity of natural habitats, while urban sites held less than 10% of the natural areas’ beta diversity

Summary

Introduction

Landscape changes due to human activities are the main cause of the recent biodiversity crisis [1], [2], [3]; the scale and magnitude of these changes has created a matrix of human-altered biomes, the so called anthromes of the Anthropocene [4]. One of the leading consequences of these negative impacts is biotic homogenization, i.e., the increasing similarity of biotas of large geographical areas over space and time, a multitaxa global phenomenon [7], [8], [10], [11], [12], [13]. Urban sprawl occurs concurrently with an increase in human population density, which is accompanied by significant negative impacts on biodiversity and ecosystem services [14], [15], [16]. The largest country in the Neotropical realm, is rapidly accumulating empirical evidence concerning the impacts of human-induced landscape modifications on biodiversity [8], in the Brazilian Atlantic Rainforest [26], [27], [28]. At the same time, considering the costs of large scale sampling in megadiverse countries both in space and time, citizen science initiatives are especially powerful tools to help survey and monitor biodiversity [32], [33]

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