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Quantification of submerged wood in a lowland Australian stream system
Author(s) -
O'CONNOR NICHOLAS 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.tb00548.x
Subject(s) - riparian zone , snag , hydrology (agriculture) , environmental science , biomass (ecology) , eucalyptus camaldulensis , stream bed , cobble , erosion , streams , riffle , coarse woody debris , habitat , ecology , sediment , geology , eucalyptus , biology , geomorphology , computer network , geotechnical engineering , computer science
SUMMARY 1. The importance of submerged wood (snags) as macroinvertebrate habitat was evaluated in the Pranjip‐Creightons Creek system, a lowland stream system in northern Victoria. Snag surface area and biomass were measured at ten sites along the system. The first four upstream sites, located in the foothills of the Strathbogie Ranges, and the next three sites, on the northern Victorian riverine plain, were affected by streambank erosion and high sediment loads and contained little instream wood. A further three sites (Sites 8, 9 and 10) downstream on the riverine plain were not as affected by erosion and possessed extensive stands of riparian river redgum, Eucalyptus camaldulensis , which contributed large amounts of wood to the stream channel. 2. Wood quantities at Site 8 were less than at Sites 9 and 10 downstream where the density of riparian redgum was greater. At Sites 9 and 10, snag surface area per m 2 of stream bed was 0.57–0.92m 2 and 0.38–0.71m 2 depending on discharge. Total snag biomass in the stream channel at the same sites was 26 and 41kg m −2 , respectively. Redgum was important to macroinvertebrates as habitat, at one site contributing 25% of total macroinvertebrate densities and over 30% of total macroinvertebrate biomass m −2 of stream bed. 3. Estimations of nitrogen content and C:N ratios of decayed redgum were carried out to provide information on its putative nutritional quality to xylophagous macroinvertebrates. Decayed redgum wood has a comparatively high N content and therefore a low C:N ratio, but appeared to be unpalatable to most macroinvertebrates. Only two macroinvertebrate species, the chironomid larvae Stenochironomus sp. and Dicrotendipes sp., were found to consume decayed redgum.