Anthropogenic changes in the aquatic environment can influence macroinvertebrate communities, interfering in species richness and diversity. Functional feeding classification of aquatic organisms enhances the knowledge on trophic dynamics in streams by simplifying the benthic community into trophic guilds – functional feeding groups. However, few studies have investigated the effect of urbanization in streams using functional feeding groups. The aim of this study was to compare aquatic macroinvertebrate assemblages in streams located in urban and preserved areas in the Atlantic Rainforest domain concerning the functional feeding categories. Sampling was conducted 10 urban and 10 preserved streams during the dry season (August–September) of 2012. The streams were characterized with respect to their environmental conditions. The macroinvertebrates were identified and classified into five functional feeding categories (collectors-gatherers, collectors-filterers, predators, scrapers and shredders) according to literature data and analysis of the gut contents.
Results/Conclusions
Collectors-gatherers and scrapers were the most frequent groups. We observed that practically all macroinvertebrates fed upon fine detritus which indicates the importance of this food resource in tropical streams. In the collector-gatherers and shredders categories the most common items found were diatoms, fungi and chlorophytes. The diatoms, fungi and plant detritus were the most common items found in gut contents of scrapers and collectors-filterers. Chironomidae (Diptera), Trichoptera and Ephemeroptera were common items in predators. The most representative functional group in urban streams was the collectors-gatherers, contributing 52.68% of the individuals (17,334 individuals distributed in 28 genera), followed by collectors-filterers (28.55%, 9,396 ind., 10 gen.) and shredders (11, 96%, 3,938 ind., 6 gen.), scrapers (3.46%) and predators (3.32%). The most common group in preserved streams was also the collectors- gatherers (44.6%, 4,709 ind., 14 gen.). Followed by scrapers which amounted to 41.62% (4,394 ind., 21 gen.), predators (9.05%, 956 ind., 21 gen.), shredders (3.1%) and collectors- filterers (0.16%). The participation of scrapers were significantly higher at preserved sites (F=5.356; p=0.033), while the collectors- gatherers (F=4.566; p=0.047) and collectors- filterers (F=13.46; p=0.002) had the opposite behavior. In urban streams, changes in food resources probably altered the functional feeding categories composition.