Longitudinal diversity patterns in streams: comparing invertebrates and fish communities

Reyjol, Yorick; Compin, Arthur A.-Ibarra; Lim, Puy


The aim of our study was to compare the longitudinal pattern of invertebrate EPTC (Ephemeroptera-Plecoptera-Trichoptera-Coleoptera) taxa richness and fish species richness, at the Adour-Garonne drainage basin scale (SW France). We considered 177 sampling sites for invertebrates and 109 sampling sites for fish, spread over the whole stream system. The statistical treatment consisted in simple linear regressions including bootstrap simulations, performed between the logarithm of EPTC taxa or fish species richness and the logarithm of the distance from the source. The model obtained for EPTC fitted a parabola with a maximal taxa richness in the intermediate part of the river continuum, while the model obtained for fish corresponded to a linear increase in species richness with the distance from the source. This difference in spatial distribution pattern is discussed with respect to the benthic nature of invertebrates vs. the pelagic nature of most fish species.


longitudinal diversity patterneptc taxa richnessfish species richnessbootstrap simulationsadour-garonne drainage basin