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

Abstract

Chile's 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 Chile's 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, expertvalidated type specimen data for the bees of Chile. We used a generalised dissimilarity modelling (GDM) approach to explore both compositional and phylogenetic β-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.

Fine‐scale bee species distribution models: Hotspots of richness and endemism in South Africa with species‐area comparisons

“…Future analysis, using our species distributional models, can also be extended to calculate other patterns of diversity such as betadiversity (species turnover) and functional diversity (e.g., Leclercq et al, 2023;Marshall et al, 2023). Because of the high numbers of range-restricted taxa confined to small numbers of grid cells, habitat specialisation is most likely driving high species turnover and functional diversity in the Winter rainfall bee hotspot and the Aseasonal rainfall bee hotspot.…”

“…The high bee diversity of Mediterranean and arid climate regions has attracted much attention over the past few years (Kaloveloni et al, 2018;Leclercq et al, 2023;Marshall et al, 2023;Meiners et al, 2019;Orr et al, 2021). We place South Africa's bee diversity within this global pattern and compare how richness scales with area (Gotelli & Colwell, 2001) within South Africa-taking into account different biomes and rainfall seasons-and with studies from other arid and Mediterranean regions worldwide.…”

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

“…This dataset included 35,743 records from 168 species. We supplemented these two datasets with information from three other sources: (1) data from type specimens of taxa described from Chile (Ascher, unpublished; Marshall et al, 2023); (2) iNaturalist research‐grade observations of wild bees from Chile (downloaded from GBIF.org, 11 February 2022; https://doi.org/10.15468/dl.9z642v), including 1829 observations of 88 species mostly identified or validated by JSA; and (3) a dataset of 1760 wild bee occurrences from 90 species collected by authors CV, PHP, and AB, between 2016 and 2018 in Central Chile (see Appendix S2: Box S2 for details). All data sources have been validated through secondary checking by experts.…”

“…This dataset included 35,743 records from 168 species. We supplemented these two datasets with information from three other sources: (1) data from type specimens of taxa described from Chile (Ascher, unpublished;Marshall et al, 2023) Citizen science and museum collection data contain opportunistic observations and those resulting from systematic sampling. These records represent a mix of spatiotemporally unique occurrences and those comprising, by design or fortuitously, records from many years for a single locality (Ascher, Marshall, et al, 2020).…”