Les opilions dans les écosystèmes montagnards pyrénéens. I Les opilions de la haute vallée d'Ossau (Pyrénées-Atlantiques; France)

A study carried out in upper-Ossau valley (Pyrenees- Atlantiques; France) between 1987 and 1989 has revealed a high diversity of Opilionid fauna in such mountain area: eighteen species have been found. In this paper, the main features of their phenology, altitudinal distribution and ecology are presented.