Homogenization of Macroinvertebrate Assemblages and Asiatic Clam Corbicula fluminea Invasion in a River of the Arid Patagonian Plateau, Argentina

Yeny Labaut,Gustavo Darrigran,Fernando M Archuby,Pablo A Macchi

doi:10.3389/fenvs.2021.728620

Abstract

The invasion of the Asiatic clamCorbicula flumineain South America has already reached Patagonia. Despite the well-known direct and indirect impacts that this species exerts on fresh-water ecosystems, particularly on benthic communities, few studies have been undertaken on its effect on the composition and structure of aquatic macroinvertebrate assemblages. This study evaluated the effects of the invasion of the Asiatic clamC. flumineaon the aquatic macroinvertebrate assemblages of the Limay River, one of the most important rivers of the arid plateau of Argentinian Patagonia. As this river is currently in the process of being invaded, it was possible to compare invaded and non-invaded sites. Invaded sites displayed a certain homogenization of their constituent species and functional composition. Non-metric multidimensional scaling, similarity analysis and similarity percentages showed negative or positive influence of the presence of this species on the abundance of some taxa, due to competition for resources in this low-productivity Patagonian ecosystem. The deposition of the faeces and pseudo-faeces ofC. flumineaenriches the organic content of the sediments. However, its pedal feeding can function as a competitive strategy: by consuming its own deposited organic matter when food is scarce, the amount available to other macroinvertebrates is reduced. This paper is the first contribution on the impact of this invasion on northern Patagonia’s aquatic macroinvertebrate assemblages.

Highlights

In the current context of globalization, biological invasions constitute one of the main threats to biodiversity (Bellard et al, 2016; Essl et al, 2020)
In the context of the oligotrophic Limay River of northern Patagonia, the present study demonstrated that gastropod populations are reduced in communities invaded by C. fluminea
The invasive species C. fluminea had a negative influence on the abundance values of some taxa such as gastropods, bivalves, Coleoptera and Trichoptera, due to the competition for the food resource, in these habitually not-very-productive arid Patagonian habitats

Summary

Introduction

In the current context of globalization, biological invasions constitute one of the main threats to biodiversity (Bellard et al, 2016; Essl et al, 2020). Invasive bivalves cause biotic and structural changes that influence aquatic macroinvertebrate assemblages (Darrigran et al, 1998; Darrigran and Damborenea, 2011; Wittmann et al, 2012; Werner, 2014). The final impact of each invasion on these organisms is difficult to predict (Lodge, 1993). Invasive species can rapidly replace native taxa (Bachmann et al, 2001; Brown and Barney, 2021), or cause increases in the abundance of favored native taxa Established communities can even facilitate the invasion process of these species (Mörtl and Rothhaupt, 2003)

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