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Longitudinal macroinvertebrate assemblages in contrasting discontinuities: the effects of damming in tropical streams
Author(s) -
Mwedzi Tongayi,
Bere Taurai,
Siziba Nqobizitha,
Mangadze Tinotenda,
Bangira Courage
Publication year - 2016
Publication title -
african journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.499
H-Index - 54
eISSN - 1365-2028
pISSN - 0141-6707
DOI - 10.1111/aje.12281
Subject(s) - sass , streams , hydrology (agriculture) , environmental science , water quality , community structure , ecology , geology , biology , geotechnical engineering , programming language , computer network , computer science
The study assessed the impact of damming on water quality and macroinvertebrate assemblages. It also assessed the response of macroinvertebrate‐based indices of water quality to damming. Macroinvertebrate community and physicochemical variables data were collected from 86 sites. Twenty‐nine sites downstream of dams were compared with 27 sites above impoundments and 30 sites on nearby unregulated streams. Of the downstream sites, 13 were situated <1 km from a dam while the other 16 were situated >1 km from a dam. A decrease in temperature, dissolved oxygen, conductivity and total dissolved solids was observed in sites immediately downstream of impoundments. Macroinvertebrate community structure and South African Scoring System ( SASS ) scores closely followed the damming‐induced changes in water quality. However, water quality variables, macroinvertebrate community structure and SASS scores reverted back to typical upstream conditions in distances around 1 km from dams. Stream recovery from dam‐induced changes was demonstrated with streams recovering at distances around 1 km from the point of regulation in corroboration with predictions of the serial discontinuity concept ( SDC ). These dam‐induced changes also reflected themselves in SASS scores suggesting potential usefulness of SASS in monitoring ecological integrity of tropical rivers following disturbances like damming.