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bioRxiv · 10.1101/2022.09.13.506767

Chilean bee diversity: Contrasting patterns of species and phylogenetic turnover along a large-scale ecological gradient

Marshall, L.·Ascher, J. S.·Villagra, C.·Beaugendre, A.·Herrera, V.·Henriquez-Piskulich, P.·Vera, A.·Vereecken, N. J.
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Abstract

Chiles isolation and varied climates have driven the evolution of a unique biodiversity with a high degree of endemism. The Mediterranean-type biome of Central Chile is one of 35 global biodiversity hotspots and has been highlighted as one of Chiles most endangered areas. It is threatened by anthropogenic land use change impacting the integrity of local biomes and associated species. This area holds the most extensive collections of the country with high endemicity regarding native bee species. Characterising habitat requirements of bees is a pressing priority to safeguard them and the ecosystem services they provide. We investigated broad-scale patterns of bee diversity using newly accessible expert-validated datasets comprising digitized specimen records from both Chilean and US collections and novel, expert-validated type specimen data for the bees of Chile. We used a generalised dissimilarity modelling (GDM) approach to explore both compositional and phylogenetic {beta}-diversity patterns across latitudinal, altitudinal, climate and habitat gradients in well-sampled bee assemblages in Central Chile. Using the GDM measures of increasing compositional and environmental dissimilarity we categorised and compared the most important drivers of these patterns and used them to classify wild bee ecoregions (WBE) representing unique assemblages. Turnover of bee assemblages was explained primarily by latitudinal variation (proxy for climate) along Chile. However, temperature variations, precipitation and the presence of bare soil also significantly explained the observed patterns. In comparison, we observed less turnover in phylogenetic biodiversity corresponding to spatial gradients. We were able to develop six de novo ecoregions (WBE) all with distinct taxa, endemic lineages, and representative species. The WBE represent distinct spatial classifications but have similarities to existing biogeographical classifications, ecosystems and bioclimatic zones. This approach establishes the baseline needed to prioritise bee species conservation efforts across this global biodiversity hotspot. We discuss the novelty of this classification considering previous biogeographical characterisations and its relevance for assessing conservation priorities for bee conservation. We argue that Chiles WBE show areas requiring funding for bee species exploration and description, distribution mapping and strengthening of conservation policies.

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Marshall, L., Ascher, J. S., Villagra, C., Beaugendre, A., Herrera, V., Henriquez-Piskulich, P., Vera, A., Vereecken, N. J.. 2022-09-15. Chilean bee diversity: Contrasting patterns of species and phylogenetic turnover along a large-scale ecological gradient. https://doi.org/10.1101/2022.09.13.506767

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