Macrophyte species diversity and distribution in relation to water quality of the Cheleleka Wetland in Ethiopia

Abstract

The Cheleleka Wetland is located in the Ethiopian Rift Valley on the upper shore of Lake Hawassa, after which the regional capital is named. This study investigated the relationship between water quality and the occurrence and diversity of macrophyte species of the wetland. Spatio-temporal variability in terms of water quality and macrophytes were studied in the wet and dry seasons at purposely-selected sites selected based on human disturbance levels. Six sites were selected, two from each of ‘severely’, ‘moderately’ and ‘least disturbed’, and data collected on water quality parameters, macrophytes richness and abundance. The results showed 25 macrophyte species dominated by Cyperaceae (24%), Poaceae (20%) and Nymphaeaceae (12%). Species diversity and abundance were significantly different between seasons and among the sampling sites (p < 0.05), with the richest taxa recorded at the least disturbed sites. A redundancy analysis of the species–environment relationships identified nutrient loads as significant drivers of macrophyte diversity and abundance in the wetland. Generally, the results showed the spatial and temporal variation of macrophyte diversity and abundance are affected by water quality, and poor water quality has resulted in poor ecological conditions of the Cheleleka Wetland.