Structure et évolution saisonnière des populations de Copépodes, Cladocères et Ostracodes des rizières de Camargue

Abstract

The ricefields form temporary aquatic environments in summer, and 41 species of Copepoda, Cladocera and Ostracoda were collected from 33 ricefields covering the whole of the Camargue.Eight dominant species were recognised from a study of the structure of the populations.The analysis of the succession of the dominant species and the use of indices of diversity and variety showed that seasonal development of the populations was divided into two phases:- an early phase in spring when biological diversity is relatively poor; Moina brachiata and Metacyclops minutus are abundant.- a mature phase in summer when the number of species increases; Crypto-cyclops bicolor appears at the end of the season; the trophic relationships become complicated.The impact of human activities (phytosanitary treatments, etc.) on the populations is discussed. © 1977 Masson.