Can upwelling regions be potential thermal refugia for marine species during climate warming? The case of Mexico

Abstract

Anthropogenic climate warming will change the thermal habitats of marine species worldwide. Species are expected to migrate to higher latitudes as warming intensifies since behavioral and physiological mechanisms have been adapted to maximize fitness under a specific range of temperatures. However, given the possible intensification of upwelling ecosystems, they may act as potential thermal refugia under climate warming, which could protect the diversity of the marine ecosystems, making them important regions for marine resource management. This research aimed to predict the effects of climate warming on commercial and non-commercial marine species (vertebrate and invertebrates) reported in official Mexican documents (> 300 species) based on a thermal niche characterization with the objective to observe if the upwelling regions can act as potential thermal refugia. For this, we considered Representative Concentration Pathway (6.0 and 8.5) scenarios for the present and the future (2040-2050 and 2090-2100). Current and future patterns of suitability, species distribution, richness, and turnover were calculated via ecological niche models using the minimum volume ellipsoids as an algorithm. The results in this study highlight that beyond migration to higher latitudes, some upwelling regions (not all) could be potentially used as some type of "oasis" by marine species refuging from environmental pressure or zones of higher stability of species. Specifically, the upwelling systems in western Baja California and north of Yucatan may be essential regions for future management in Mexico. Nevertheless, it is important to note that climate change acts on numerous ecosystem features, such as trophic relationships, phenology, and other environmental variables not considered here. Future research could test our hypothesis under more realistic simulations. However, migration toward upwelling regions seems to be the most logical selection from all the available ecosystems as climate refugia for marine species beyond movement to higher latitudes or depths.