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Ecology of invertebrate predators in a Coastal Plain stream
Author(s) -
SMITH LANE C.,
SMOCK LEONARD A.
Publication year - 1992
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1992.tb00590.x
Subject(s) - guild , predation , chironomidae , trophic level , invertebrate , predator , ecology , biology , detritus , biomass (ecology) , odonata , abundance (ecology) , habitat , larva
SUMMARY 1. The spatial and temporal abundance patterns, production and feeding habits of invertebrate predators were determined in a sand‐bottomed, headwater stream in Virginia, U.S.A. 2. Annual mean density and biomass of predators in debris dams were 3897 individuals m −2 and 2.5 g dry mass m −2 , respectively, but only 711 individuals m −2 and 0.2 gm −2 on the sediment. Predator production was 8.36 gm −2 yr −1 in debris dams compared to 1.52 gm −2 yr −1 on the sediment. Annual predator production, weighted by habitat availability, was 1.73gm −2 yr −1 . 3. The predominant taxa in terms of production were the chironomids Thienemannimyia spp, complex, Ablabesmyia parajanta, Zavrelimyia sp., and the odonate Cordulegaster maculata . Chironomidae and Odonata together comprised 77% of the production of the predator guild. 4. Based on gut content analysis and calculations of the trophic basis of production, estimated predator production was supported mostly by Chironomidae (38%), detritus (20%), unidentifiable insects (14%), and Ephemeroptera (11%). Total food ingestion by predators was 9.8 gm −2 yr −1 , 63% of which was detritus and 37% of which was animal material on an areal basis. The predator guild consumed an estimated 94% of primary invertebrate consumer production on the channel surface of the stream.