Communities of terrestrial invertebrates from Diego Ramírez archipelago (56°31’S), the southernmost long term ecological research site of the Americas: diversity and affinities with other Subantarctic Islands from the Southern Ocean

Abstract

The Diego Ramírez and Cape Horn archipelagos are located at the southern end of the Magellanic subantarctic ecoregion. The fauna of insects and other terrestrial invertebrates has been poorly characterized. In this work, we present an updated assessment of invertebrates, with a focus on the terrestrial entomofauna of the Diego Ramírez Archipelago. We reviewed biogeographic affinities of this southern archipelago with the rest of the subantarctic islands. We found that Gonzalo Island in the Diego Ramírez Archipelago is free of insect species and other exotic invertebrates. The island’s terrestrial invertebrate fauna registered during this study includes 32 taxa, mainly from the Class Insecta, which are distributed in different habitats, being the communities of Poa flabellata the most important habitats. The entomofauna of the Diego Ramírez Archipelago shows a low total similarity between the fauna reported and the rest of the islands, except with South Georgia. However, the biota that links them is of Gondwanic origin, which suggests the existence of ancient vicariant biogeographic connections. This work is a contribution to the development, strengthening and inauguration of the Cape Horn Long-Term Ecological Monitoring Network (LTER Cape Horn Network). The particular focus on the Diego Ramírez Islands contributes directly to filling a “blind spot” in our current knowledge of the effects of global environmental change in sub-Antarctic ecosystems, generating information essential to their conservation in the short, medium and long term.