Structure and dynamics of a benthic trophic web in a Mediterranean seasonal stream

Abstract

In this work we present the results of a study conducted on the benthic macroinvertebrate community of a Southern Spain seasonal stream over a year. We constructed the food web focusing on the benthic fauna and we studied the ecology and dynamics of the community in terms of trophic resources. The benthic trophic web was composed by 35 families; these were not all present at the same time, but were incorporating and disappearing throughout the study period. Connectance between trophospecies varied from 0.24 to 0.59. The functional feeding group (FFG) composition of the community turned out to be fairly constant with time with a predominance of scrapers and collector-gatherers. Furthermore, data obtained from the Bray-Curtis measure and the niche overlap study, evidence the stability of the stream from a trophic point of view. Rather widespread is omnivory that plays an important role in the survival of some families. We compared the results of the trophic web study with those of other temporary streams of the same region of Southern Spain.