Ecosystem stability depends to a great extent on food web structure. Recent research indicates that in particular the share of weak links in the web is a crucial feature. Link strength is to some extent related to feeding strategy, i.e. specialists should have stronger links to their prey than generalists. Therefore a closer look at the distribution of feeding strategies among the species representing a system may already provide some hints on link strength distribution.Information on diet and feeding strategy is easily obtained from species who offer a neat view on their stomach content, such as fish. Systems that comprise of animals which are small, ingest lots of ballast together with their food, are much more difficult to handle. Soft-bottom macrozoobenthic communities combine these unfavourable features, and therefore are widely neglected in detailed studies of trophic functioning. We used a stable isotope approach referring to the soft-bottom macrozoobenthic subsystem of the German Bight to tackle this problem. The relation between intra-population range in nitrogen isotopic ratios (δ15N) and feeding strategy was analysed. We hypothesize that the δ15N range is a proxy for trophic niche width and thus (i) is indicative of feeding strategy, i.e. omnivore/generalist, specialist, ontogenetic diet shifter; and (ii) will provide quantitative information on basic trophic differences.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > CO2-Coastal diversity - key species and food webs