Anthropogenic effect on wetland biodiversity in Lake Tana Region: A case of Infranz Wetland, Northwestern Ethiopia

Abstract

This study evaluates the effect of anthropogenic activities on Infranz Wetland biodiversity in Lake Tana area. Plant biodiversity data were collected from quadrants that were established in transect lines and macroinvertebrates were collected using 500 μm mesh size. A survey with 386 households, four focus group discussions and 24 key informant interviews were conducted to capture socioeconomic data. Shannon-Wiener diversity index, species percentage distribution and dominance, regeneration status and ecological importance index were computed to evaluate the plant and macroinvertebrates condition. Descriptive statistics were used to analyze the survey data and qualitative data were analyzed thematically. The results of the biodiversity data showed ecological degradation of the study wetland. Though woody plants had rich (3.08) species diversity, more than 30% of species were represented only by four families which reflects overharvesting of the desired woody plant species. The non-ecological importance of 81.5% floristic plant species and the dominance of few macroinvertabrates such as tolerant taxa, predators and scrapers also implied the existence of habitat degradation. Furthermore, the dominance of emergent macrophytes implied the biodiversity loss of the wetland. Extraction of more than 15 billion cubic meter water for public water supply and khat irrigation, farmland expansion, eucalyptus plantation within the wetland, overgrazing and, overuse of papyrus were the principal factors for the wetland degradation and consequent loss of its biodiversity. Efforts have not been made to regulate the use of wetland resources. Thus, local governments should establish bylaws for sustainable use of the wetland.

Keywords

• Infranz wetland
• Biodiversity
• Anthropogenic activities
• Degradation