A comparative sink web analysis of two bird species in two habitats: trophic structure, functionality, aggregation and system-level indication

Changes in the trophic structure of communities are good indicators of ecosystem stress or environmental change. Here, we compare the sink webs of two bird species (great tit, Parus major, and European blackbird, Turdus merula) in two habitats (a forest and an orchard), in order to detect the differences in their trophic status. The webs are functionally aggregated in three steps, based on energetics. Our main conclusion is that tits are less sensitive to habitat change from the natural  to the agricultural.