Macroinvertebrate functional feeding groups in Kenyan highland streams: evidence for a diverse shredder guild

AbstractData on the functional composition of invertebrates in tropical streams are needed to develop models of ecosystem functioning and to assess anthropogenic effects on ecological condition. We collected macroinvertebrates during dry and wet seasons from pools and riffles in 10 open- and 10 closed-canopy Kenyan highland streams. We classified macroinvertebrates into functional feeding groups (FFGs), which we used to assess effects of riparian condition and season on functional organization. We used cluster analysis of gut contents to classify 86 taxa as collectors, predators, scrapers, or shredders. We classified 23 taxa whose guts were empty or had indistinguishable contents based on literature. In total, we identified 43 predators, 26 collectors, 19 scrapers, and 19 shredders. Total abundance was higher in open-canopy agricultural streams, and species richness was higher in closed-canopy forested streams. Predators and shredders dominated richness and biomass, respectively, in the closed-canopy stre...