The Role of Small Lowland Patches of Exotic Forests as Refuges of Rare Endemic Azorean Arthropods

Noelline Tsafack,François Rigal,Alejandra Ros-Prieto,Simone Fattorini,Mário Boieiro,Maria Teresa Ferreira,Paulo A. V. Borges

doi:10.3390/d13090443

Abstract

Islands have been disproportionately affected by the current biodiversity crisis. In island biotas, one of the most recurrent anthropic alterations is species introduction. Invasion of exotic species may represent a major threat for island biotas, because invasive species may change species composition and simplify community dynamics. We investigated diversity patterns of native and introduced species in native and exotic forests of Terceira Island (Azores, Portugal) by using diversity profiles based on Hill numbers. Use of diversity profiles allows for a complete characterization of the community diversity because they combine information on species richness, rarity, and dominance. We found that native forest remnants are crucial for the maintenance of endemic Azorean arthropod diversity. However, we also found that some lowland patches of exotic forests can sustain populations of rare endemic species. Our findings reinforce the importance of the few and small remnants of native forests, which are a pillar to the conservation of Azorean endemic arthropods. However, areas occupied by exotic forests, whether they are large and contiguous or small and isolated, close to native forests, or embedded in a matrix of agriculture activities, can also play a role in the conservation of native species, including endemics.

Highlights

A growing number of studies are providing clear evidence of an unprecedented and rapid decline in arthropod communities [1,2,3,4], with alarming decrease in flying insect biomass [5] and, more generally, in insect species diversity measures including richness and phylogenetic and functional diversity measures [6,7,8].Islands have been disproportionately affected by the current biodiversity crisis [9,10]
We investigated the occurrence of endemics, native non-endemic, and introduced species in native and exotic forests of Terceira Island (Azorean Islands)
Our findings reinforce the results of previous studies showing that the few and small remnants of native forests are a pillar to the conservation of Azorean endemic arthropods

Summary

Introduction

A growing number of studies are providing clear evidence of an unprecedented and rapid decline in arthropod communities [1,2,3,4], with alarming decrease in flying insect biomass [5] and, more generally, in insect species diversity measures including richness and phylogenetic and functional diversity measures [6,7,8].Islands have been disproportionately affected by the current biodiversity crisis [9,10]. A growing number of studies are providing clear evidence of an unprecedented and rapid decline in arthropod communities [1,2,3,4], with alarming decrease in flying insect biomass [5] and, more generally, in insect species diversity measures including richness and phylogenetic and functional diversity measures [6,7,8]. Invasion of exotic species may represent a major threat for island biotas, because invasive species may change species composition and simplify community dynamics [15,16,17,18]. Colonized by the Europeans since the fifteenth century, the Azorean Islands (Portugal) are an example of the impact of alien insects on island faunas. Exotic species constitute today a great part of the arthropod fauna of the Azores, reaching almost 60%

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Conclusion