Benthic organic matter and macroinvertebrate functional feeding groups in a forested upland stream in temperate Victoria

Summary

Intensive benthic sampling for 1 yr showed no marked seasonal variations in the standing stock of benthic organic matter (> 50/μm) at a site on the Acheron River (145 ° 42′ E, 37°35′ S). Detritivorous feeding groups (collectors, shredders) were poorly correlated with the standing stocks of organic matter, and many species were able to use alternative feeding modes (e. g. scraping). This suggests that the quantity of detritus is not the primary criterion for habitat selection by detri- tivores as a whole. If food is important, then either quality or restricted size ranges of detritus could be better predictive variables. Predators and scrapers, however, showed closer relationships with their putative food resources.