Abstract |
Current environmental changes due to increased human activities are impacting biodiversity and distribution of marine organisms. Understanding species diversity is essential for assessing threats, predicting impacts, and guiding conservation planning. Our study focuses on the family Leptocheliidae (Crustacea: Tanaidacea), a suitable model for investigating diversity and distribution in low-mobility crustaceans. This family, abundant in shallow waters and sensitive to environmental shifts, was analyzed globally using literature, databases, and unpublished data from Australian coral reefs. We calculated species richness, estimated richness, and sampling effort, organizing data into latitudinal bands and ca. 800,000 km2 hexagonal cells. Cluster analysis by biogeographic provinces helped identify distinct species assemblages.
Generalized Linear and Additive Models (GLM, GAM) assessed environmental drivers, including temperature, productivity, chlorophyll, dissolved oxygen, salinity, silicate, phytoplankton, nitrate, and phosphate. Results revealed a bimodal species richness pattern, with diversity peaking in lower latitudes but declining at the equator. Biodiversity hotspots were identified in the Indo-Australian region, Central Indo-Pacific, Gulf of Mexico, and Caribbean, with high estimated richness in the Mediterranean, and SE Australia. The subantarctic region displayed distinct, but low-diversity assemblages.
Among the environmental variables, dissolved oxygen was identified as the most important factor influencing species diversity and estimated diversity across latitudes, followed by temperature. Models incorporating salinity, combinations of multiple factors, and dissolved oxygen were the most reliable for species diversity within hexagonal regions, while combinations of several environmental factors, followed by temperature, were the best predictors for estimated diversity.
|