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Alien bird species decrease the diversity of bird communities across human-disturbed landscapes
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  • Fabio Marcolin,
  • Pedro Segurado,
  • Daniel Chamberlain,
  • Luis Reino
Fabio Marcolin
Universidade de Lisboa Instituto Superior de Agronomia

Corresponding Author:fabiomarcolin@isa.ulisboa.pt

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Pedro Segurado
Universidade de Lisboa Centro de Estudos Florestais
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Daniel Chamberlain
Universita degli Studi di Torino
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Luis Reino
CIBIO-University of Porto
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Abstract

Introduced alien species have direct and indirect effects on native communities, leading to lower taxonomic diversity and negative impacts on ecosystem functioning. Moreover, other aspects of diversity could be negatively affected, through alteration of functional and phylogenetic diversity of a community. This is particularly evident in habitats where human disturbance may favour alien species, posing an additional stressor on native communities. Following the community resistance hypothesis (higher diversity, higher resistance to invasion), we hypothesized: i) higher taxonomic, functional and phylogenetic diversity (TD, FD and PD respectively) in non-invaded bird communities (i.e. no alien bird species); and, ii) lower alien species impact on all diversity metrics in less human-disturbed areas. We surveyed bird communities in a modified Mediterranean landscape subject to varying levels of human disturbance. We tested whether TD, FD and PD indices were significantly different between non-invaded and invaded bird communities, and assessed the effect of landscape composition and configuration on these indices. We found that non-invaded communities retained higher TD and FD than invaded communities. Alien birds occupied novel parts of the functional space in invaded communities, but that they did not fully compensate for the taxonomic and functional diversity loss caused by the absence of native species. These results were consistent across different habitats, suggesting weak environmental filtering of communities. Generally, both communities were negatively affected by more human-disturbed areas (e.g. agriculture and urban areas) and enhanced by forest areas and by landscape heterogeneity. Our results suggest that the occurrence of alien birds negatively affects TD and FD (but not PD) of bird community assemblages, but that this impact is stronger in human-modified landscapes. Therefore, since the conservation of biodiversity in anthropogenic habitats is a worldwide challenge, researchers should prioritize efforts to assess the effects of alien species on communities inhabiting those habitats.
18 Apr 2023Submitted to Ecography
20 Apr 2023Submission Checks Completed
20 Apr 2023Assigned to Editor
20 Apr 2023Review(s) Completed, Editorial Evaluation Pending
20 Apr 2023Reviewer(s) Assigned
26 May 2023Editorial Decision: Revise Major
06 Jul 20231st Revision Received
07 Jul 2023Submission Checks Completed
07 Jul 2023Assigned to Editor
07 Jul 2023Review(s) Completed, Editorial Evaluation Pending
21 Jul 2023Reviewer(s) Assigned
20 Aug 2023Editorial Decision: Accept