Macroinvertebrate production and trophic structure in a tallgrass prairie headwater stream

TitleMacroinvertebrate production and trophic structure in a tallgrass prairie headwater stream
Publication TypeJournal Article
Year of Publication2002
AuthorsStagliano, DM, Whiles, MR
JournalJournal of the North American Benthological Society
Pagination97 -113
Accession NumberKNZ00799
KeywordsAquatic macroinvertebrates, Energy flow, Food web, Konza Prairie Biological Station, organic matter, Prairie stream, secondary production, Trophic structure

Research on North American prairie stream communities has lagged behind other regions. We examined the ecosystem significance of the macroinvertebrate community of riffle/run habitats in Kings Creek, a 2nd-order tallgrass prairie stream at Konza Prairie Biological Station (Kansas, USA), by estimating secondary production, benthic organic matter standing stocks, and resource consumption and egestion by functional groups. Annual mean standing stock macroinvertebrate biomass was 2.3 g ash-free dry mass (AFDM)/m2, annual production was 19.7 g AFDM m-2 y-1, and the annual community production/biomass (P/B) ratio was 8.6. Macroinvertebrate production was higher than published estimates for forested streams of similar size, but much lower than that of a Sonoran desert stream. Distribution of production among functional groups was 30% for collector-gatherers, 9% for collector-filterers, 20% for scrapers, 23% for shredders, and 18% for predators, resembling estimates from some forested streams with the exception of higher scraper production. Although detritivorous groups were productive in this prairie stream, they appeared food limited. Consumption estimates indicated shredders and collector-gatherers annually ingested ∼80% and ∼240% of coarse particulate organic matter (CPOM) and fine particulate organic matter (FPOM) standing stocks, respectively. Thus, re-ingestion and/or diet shifts may be common, particularly among collector-gatherers, and the FPOM pool must turn over rapidly. Invertebrate predators also consumed a sizeable portion (∼52%) of prey, whereas scrapers (∼21%) and filterers (<1%) consumed relatively small portions of their respective resources, suggesting top-down influences on these groups. This study indicates that, during a period of relatively stable flow in this prairie stream, macroinvertebrate production and functional structure were roughly intermediate between North American forested and desert systems. Our results underscore the value of secondary production estimates for examining invertebrate communities in an ecosystem context