Open AccessDistribution of benthic invertebrates at different depths in a shallow reservoir in the KwaZulu-Natal Midlands
Author(s) -
Michael J. Samways,
Russell S. Osborn,
Ivor van Heerden
Publication year - 1996
Publication title -
koedoe
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 29
eISSN - 2071-0771
pISSN - 0075-6458
DOI - 10.4102/koedoe.v39i2.295
Subject(s) - invertebrate , macrophyte , baetidae , benthic zone , ecology , biology , waves and shallow water , odonata , elodea canadensis , chara , waterfowl , fishery , aquatic plant , habitat , oceanography , geology
The bottom of a freshwater reservoir in the KwaZulu-Natal Midlands was sampled for macro-invertebrates and macrophytes at depths of 0.5 m, 1 m, 2 m, and 3 m. The water plants Elodea spp. which did not occur much beyond 1 m appeared to be a major deter-minant for the presence of invertebrates. At 2 m and 3 m, when temperature and light decreased greatly, it was replaced by the algae Chara spp. Over 98 of the macroinvertebrate individuals in 21 species and 14 families occurred in water 1 m or less in depth. At 2 m and deeper, there was a rapid decline of species, with only one, a snail, occurring at 3 m. Odonata species occurred only in water 1 m or less in depth. Among the Ephemeroptera, Caenis sp. was abundant at 0.5 m and the most dominant species of all. At 1 m, the most dominant species was Cleon palidulosum of the Baetidae. Both in terms of food for waterfowl and trout, and as a reserve for aquatic macroin vertebrates, the shallow fringe of the reservoir was playing by far the major role compared with the deeper, open water. It is recommended both for biotic conservation and fishing that reservoirs have a shallow rim and constant water levels