A thorny future for sea urchins in the Tropical Western Atlantic
Under climate change, many functional pathways may be disrupted by induced changes in the distribution of key species. Sea urchins significantly contribute to bioerosion and herbivory rates in coral reefs, assuming a leading role in certain regions. Thus, regional losses of sea urchin populations can potentially impact coral reefs in the Atlantic. Here we modeled the potential distribution of three widely distributed sea urchins of the tropical Atlantic (Lytechinus variegatus, Echinometra lucunter and Tripneustes ventricosus) in three future climate change scenarios for 2100. Species distributions were modeled using a Log-Gaussian Cox Process model in a Bayesian-based framework. Using a mechanistic model, we also assessed how changes in the thermal regime alone can lead to distributional changes. Distribution models predicted poleward range expansions for all studied species, but a relative stability in the areas where the species are currently distributed (except for L. variegatus). However, this relative stability may be caused by inherent limitations when modeling the distribution of tropical species. This is reinforced by the realized thermal niche analysis, which points out thermal regimes exceeding the historical range experienced by the species, threatening their natural occurrence in several zones of the Caribbean. Our results highlight that achieving the targets outlined in the Paris Agreement to reach the best-case scenarios is necessary to ensure the persistence of sea urchins on coral reefs along the Tropical Western Atlantic.
This article is under submission.
A thorny future for sea urchins in the Tropical Western Atlantic
Principe, Silas C.1,2, Acosta, André L.3, Lotufo, Tito M. C.1
1 Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brasil. 2 Intergovernmental Oceanographic Commission of UNESCO, Ocean Biodiversity Information System, Oostende, Belgium. 3 Planetary Health Brazil, Institute of Advanced Studies, Universidade de São Paulo, São Paulo, Brasil.