Effects of climate on the mole crab Emerita brasiliensis on a dissipative beach in Uruguay

摘要

ABSTRACT: Climate change is expected to have considerable impacts on sandy beach ecosystems through the loss of intertidal area and changes in physical properties. These changes may affect demography and life history traits of macrofaunal species. We evaluated the role of climate in explaining variations in population traits of the mole crab Emerita brasiliensis over 20 yr on a sandy beach in Uruguay, based on a set of predictive hypotheses recently developed from studies of beach and climate-change ecology. Population abundance increased with sea surface temperature (SST), reproductive and recruitment periods were more extended, and recruitment was higher during warm years, when population structure showed a multi-modal structure. Decreasing asymptotic sizes and increasing growth rates were also observed concurrently with increasing SST. La Ni?a events, which in coastal Uruguayan waters are characterized by a higher influence of tropical oceanic waters (warm and salty), had marked positive impacts on abundance and individual growth. In a climate change scenario, an increasing frequency of extreme La Ni?a events is expected and therefore our results have strong implications. In a space-for-time substitution context, our long-term trends are reinforced by macroscale results that reported an increase in growth rates and in reproduction and recruitment periods, together with a decrease in female individual sizes, from temperate to tropical beaches of the Atlantic coast of South America. Space-for-time substitution is highlighted as an alternative approach to analyze potential population changes resulting from climate change in these data-poor ecosystems.