Talitrid and Tylid crustaceans bioecology as a tool to monitor and assess sandy beaches’ ecological quality condition

In the last decades, the sharp increase of human activities on sandy beaches has introduced several detrimental impacts on these ecosystems, highlighting the importance of developing environmental quality assessments and sustainable management and protection plans for these environments. The study of key species at the population level represents an adequate and important approach to the ecosystem's ecological quality if the impacts of environmental disturbances, namely derived from human activities, are to be assessed. Talitrid and Tylid crustaceans often form abundant populations in temperate exposed sandy beaches, and might represent the bulk of the macrofaunal communities. In the present case study, the comparison of distinct Talitrid and Tylid populations on Atlantic (Portugal) and Mediterranean (Italy and Tunisia) beaches allowed to assess the adaptation of these animals on local and macro scale scenarios and evaluate the importance of bioecological studies as auxiliary tools in environmental monitoring and in the ecological quality assessment of sandy beaches. The results revealed that Talitrid and Tylid populations have a strong plasticity over geographic gradients and to local environments, presenting a high degree of variation on population ecology, namely latitudinal clines on several life history traits. Also, since the studies were performed on sandy beaches with similar degrees of exposure to wave action and low degrees of human disturbance, the present work may play a relevant role as reference knowledge in environmental monitoring studies and as an ecological quality assessment tool that might be used to evaluate the impacts of environmental disturbances on sandy beach ecosystems, namely from human origin.