Vicariances écologiques chez les trichoptères des Pyrénées

Abstract

As a result of the diversity of their habits, the Trichoptera can be placed in distinct groups in which the species, according to their behaviour, their feeding habits and their localisation react in a similar manner to the factors of the environment. Vicariancies can be shown within these groups of which the species occupy similar ecological niches. The distribution of the species of the same group is compared and figured in graphs showing the altitude and the importance of the stream (indicated by the drainage area) in the valleys which were studied: basin of the Garonne above Toulouse, valleys of Aspe and Ossau, valley of the Aude. Six main types of distribution can be deduced from these graphs, for the Trichoptera of the Garonne basin: - species wich are quite frequent above 2 000 meters, less frequent below 1 000 meters, - species with a great altitudinal range, extending above 1 800 - 2 000 m, - species in the springs and streams at low and medium altitude, - species in mountain rivers, - species limited to rivers at low altitude, - species in large rivers, collected in the Garonne above Toulouse, rares or absents above 500 m. The types of distribution are correlated with the groupings determined statistically in the valley of Aure on one hand and with the geographical distribution of the species on the other hand. © Masson, 1968.