Abstract

Wetlands provide enormous socioeconomic and environmental values. However, wetlands are threatened by conversion for agricultural land in southwestern Ethiopia. The study aims to assess the impact of wetland cultivation on plant species richness, composition and soil fertility. Plant species richness and composition was investigated for 30 plots in each site of adjacent uncultivated and cultivated wetlands sites and total of 60 sampling plots were used. Soil samples were collected from 18 sample plots (9 in each site) selected using simple random method from plots used for plant survey. The results showed that cultivated sites have significantly higher (P<0.05) species richness, diversity and evenness indices than uncultivated wetlands. Though, this seems positive biological integrity in cultivated site, some ecologically and socioeconomically valuable wetland plant species were lost. Similarity of species (index 30.51%) between two sites was low. Moisture content, clay, organic carbon, total nitrogen, available phosphorous, cation exchange capacity (CEC), exchangeable K⁺ and Na⁺ were significantly (P<0.05) lower while silt, pH and electric conductivity (EC) were significantly (P<0.05) higher for cultivated site respect to uncultivated site. However, bulk density, sand, exchangeable Mg²⁺ and Ca²⁺ were not significantly (P>0.05) affected. Hence, planning wise use strategy for sustainable management of wetlands is essential.

Key words: Wetland cultivation, species composition, soil physico-chemical properties, South-Bench District.