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

► Talitrids and Tylids show strong plasticity over macro and local scale environments. ► Several population life history traits present latitudinal clines of variation. ► Knowledge on key species bioecology is a tool to assess environmental changes. ► Bioecological monitoring allows assessing the sandy beaches' ecological quality.