Macroinvertebrate Communities in Two Tropical Reservoirs (Lamingo and Liberty reservoirs) in Jos, Nigeria

Abstract

Macroinvertebrates are animals without backbones. Those that are adapted to aquatic life have representatives in a variety of animal groups that include hydras, worms, molluscs and arthropods. Some of them are large enough to be seen with the naked eye, though, in some cases, their detailed characteristics can only be appreciated with the aid of a dissecting microscope or an appropriate magnifying lens. This study investigated the taxon richness of macroinvertebrates in two tropical neighbouring reservoirs located in the biotite granite-rockstrewn Lamingo village in Jos North Local Government Area of Plateau state, Nigeria. These two reservoirs are subjected to different levels of human interferences. The overall idea was to provide a preliminary inventory (baseline data) of macroinvertebrate taxa in the two water bodies that will serve as references for future works in the reservoirs. A pond net was used to sample the benthic zone at the shallower parts of the reservoirs’ littoral zone, in a shovel- and rake-like manner. Benthic matter (mud, silt, sand, small gravels and detritus as well as associated invertebrates) collected was washed through a vegetable sieve and then through a tea sieve - procedures which made it possible to pick out and sort the macroinvertebrates. Captured animals were identified to family level. Lamingo reservoir had more taxa than Liberty reservoir. Out of the 199 animals recorded for the two reservoirs, 80.40 % were recorded in samples collected from Lamingo reservoir. A striking observation was that whereas mollucs (gastropods and bivalves) were present in samples collected from Lamingo reservoir, no mollusc was recorded in samples collected from Liberty reservoir. The fewer taxa recorded for Liberty reservoir could be as a result of ecological disturbance occasioned by human activities (farming on the catchment area, extraction of water for crop farming, silviculture, and for block moulding, as well as water tankers driving into the reservoir to collect water). Lamingo reservoir is far less disturbed. Some management strategies that could help reduce human impacts on the reservoirs are suggested.