摘要:This special issue stems from an increasing awareness on the key contribution made by biometrics and biological indices in the quality classification of aquatic ecosystems. This theme has been the subject of passionate debate during the 13th European Ecological Federation (EEF) and 25th Italian Society of Ecology’s (S.It.E.) joined congresses held in Rome in September 2015. In this frame, on the margins of the special symposium named “ Biomonitoring: Lessons from the past, challenges for the future ”, it was launched the idea of a special issue of the Journal of Limnology on the “aquatic” contributions presented at the conference. The present volume mainly reports these studies, enriched by few invited papers. Among the other things, the main message is the need of a better integration between sector knowledges and legislative instruments. This is even truer given the on-going climate change, and the necessity to record rapid changes in ecosystems and to elaborate effective/adaptive responses to them.