Community composition and distribution of macroinvertebrates in the Umzimvubu river, South Africa: a pre-impoundment study

• Published in: African journal of aquatic science Vol. 28; no. 2; pp. 137 - 149
• Main Authors: Madikizela, B.R. (Water Affairs and Forestry Dept., Pretoria (South Africa). Resource Quality Services), Dye, A.H
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.08.2003
• Subjects: AFRIQUE DU SUD; AQUATIC ORGANISMS; BIODIVERSIDAD; BIODIVERSITY; BIODIVERSITÉ; CALIDAD DEL AGUA; COURS D'EAU; CURSOS DE AGUA; EASTERN CAPE; ENVIRONMENTAL RESERVE; Freshwater; GESTION; GESTIÓN; Invertebrata; MANAGEMENT; ORGANISME AQUATIQUE; ORGANISMOS ACUÁTICOS; QUALITÉ DE L'EAU; RECURSOS HÍDRICOS; RESSOURCE EN EAU; RIVERS; SASS4; SOUTH AFRICA; SUDÁFRICA; TOTAL SUSPENDED SOLIDS; UMZIMVUBU RIVER; WATER QUALITY; WATER RESOURCES; South Africa, Umzimvubu R; South Africa
• ISSN: 1608-5914; 1727-9364
• DOI: 10.2989/16085910309503778

This paper presents baseline biological data on aquatic macroinvertebrates and water quality in the Umzimvubu River and selected tributaries, Eastern Cape Province, South Africa, prior to the construction of proposed large-scale water resource developments. Sampling was conducted seasonally at 14 sites between 1996 and 1998. The macroinvertebrate community composition was strikingly similar (±70%) across sites. Faunal diversity was low (104 taxa in total), but many taxa found were sensitive to water quality change (ASPT 5.0 to 9.6), indicating good water quality, which is attributed to the currently undeveloped nature of the catchment. Concentrations of water quality variables fell within a narrow range, except for total suspended solids, which at times was very high (up to 8 532mg l -1 ). The highly variable concentration of the total suspended solids and its potential effects on biodiversity need to be investigated further. It is likely that bilharzia will spread and that pest blackflies may become a problem to livestock if the water resources become developed as is proposed. We suggest that more flow gauging weirs are needed to measure flows better for future management and also that the implications of the proposed developments on the estuary need to be investigated.