Biodiversity and biogeography of hydroids across marine ecoregions and provinces of southern South America and Antarctica

MIRANDA T.; FERNANDEZ; GENZANO G. N.; COLLINI R.; MARQUES A. C

Polar Biology

Springer Science and Business Media Deutschland GmbH

Año: 2023 vol. 44 p. 1669 - 1689

To better understand the biodiversity-biogeographic polar connections between southern South America and Antarctica (SSA& A), we used benthic communities of hydroids as a model to investigate marine assemblages by evaluating classic spatialdivisions at different geographical resolutions. Using a georeferenced dataset of 249 species and multivariate analyses, weinvestigated species’ distribution, composition and biogeographic connectivity, and defined assemblages of ecoregions andprovinces for the area. Hotspots of rich biodiversity at risk of depletion were defined. Analyses of ecoregions have a morestratified biogeographic structure, and reveal critical regions susceptible to loss of diversity. Analyses of provinces showa clear division between Atlantic-Pacific and Antarctic-Subantartic assemblages, with high biogeographic isolation of theSubantarctic islands. Depending on spatial resolution, the biogeographic position of the Magellan area is spatially contradictory, clustering on the one hand with SSA ecoregions and on the other with Antarctic provinces. Our patterns appear tobe driven by different combinations of processes and barriers, reflected in the stratified distribution of hydroids. The highlevel of endemism and concentration of species at the edge of distribution in the Magellan area and Scotia Arc suggest theirtransitional nature and particular importance for understanding the historical and ecological connections between SSA & A.