Contrasting alien effects on native diversity along biotic and abiotic gradients in an arid protected area

Reham F El-Barougy,Louis-Félix Bersier,Abdel-Hamid A Khedr,Ibrahim A Elgamal

doi:10.1038/s41598-021-92763-2

Reham F El-Barougy, Louis-Félix Bersier + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-92763-2

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Abstract

Alien impact on native diversity could be a function of both the relatedness of alien species to native community and resources availability. Here, we investigated whether alien plants expand or decrease the functional and phylogenetic space of native plant communities, and how this is affected by alien relatedness to natives and by resources availability. We used a trait-environment dataset of 33 alien and 130 native plants in 83 pairs of invaded and non-invaded plots, covering a gradient of soil resources (organic matter-nitrogen) in Saint-Katherine-Protectorate, Egypt. First, we compared the changes in native composition and calculated alien relatedness to natives within each pair of plots. Second, we tested the effects of resources availability and relatedness on the magnitude of alien impact (defined as a change in native diversity). We found that native composition was phylogenetically less but functionally more diverse in invaded plots compared to non-invaded ones. Moreover, in resources-rich plots, dissimilar aliens to natives significantly increased native diversity, while in resource-limited ones, similar aliens to natives declined native diversity. These results suggest that the assessment of alien impacts in arid-regions is significantly linked to resources-availability and relatedness to natives. Hence, future studies should test the generality of our findings in different environments.

Highlights

Alien impact on native diversity could be a function of both the relatedness of alien species to native community and resources availability
We found an evidence that supports Darwin’s pre-adaptation hypothesis; native phylogenetic indices (PD, NMPD), richness and abundance were marginally lower in invaded plots compared to non-invaded ones (Table 1, Fig. 1)
Our finding indicated an inconsistency between native phylogenetic diversity (PD) and FD, which is supported by an observed decline in the phylogenetic signal of native species traits in the invaded communities compared to non-invaded ones

Summary

Introduction

Alien impact on native diversity could be a function of both the relatedness of alien species to native community and resources availability. Alien species are likely to change the richness, functional and phylogenetic diversity of the native resident community The direction of this change could depend on the ecological similarity or dissimilarity between aliens and natives, and on resources availability[8,9,10,11]. In resource-limited environments, a pattern of aliens co-occurring with functionally similar natives is expected This increasing similarity might cause the alien species to replace natives and to occupy a portion of the functional and possibly of the phylogenetic space originally occupied by the native species they replaced, leading to the contraction of the functional and phylogenetic diversity of the native resident c ommunities[24,25]. Such alien species could expand the native phylogenetic and functional diversity, compared to non-invaded communities[27], and provide a novel suit of traits and evolutionary origins to the invaded communities[28,29,30]

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