INFLUENCE OF ANTHROPOGENIC ACTIVITIES ON NYANGONGO WETLAND IN NYARIBARI CHACHE SUB-COUNTY, KISII COUNTY-KENYA

Abstract

Wetlands have a variety of crucial functions, such as flood mitigation, groundwater recharge, climate regulation, erosion prevention, and the provision of water for human use and wildlife habitats. The Nyangongo Wetland, which spans 825 hectares in Kisii County, Kenya, is a vital source of sustenance for communities living in the Lake Victoria Basin. However, due to land consolidation, the conferment of individual land rights, and population pressures, some members of the community have lost access to land, resulting in encroachment on sensitive areas like wetlands. This phenomenon can be attributed to a combination of colonial land practices and traditional customs, which have led to the encroachment of traditionally protected areas like sacred forests and communal wetlands. The study was based on the tragedy of the commons theory, which discusses open access to environmental resources, and aimed to evaluate the impact of human activities on the Nyangongo wetland over the past 37 years. To achieve this, a mixed-method approach was utilized, combining Remote Sensing and GIS-based analysis with citizen science methodology. The research findings indicate that the wetland has been adversely affected due to human-induced modifications such as water pollution, which has led to limited access to clean water and a reduction in arable land. The research utilized image analysis to determine that the size of the wetland area of which in 1984 was 72.85 hectares, but by 2021 had significantly reduced to 17.37 hectares, indicating a significant decrease of 76%. Over the same period, the vegetation area decreased from 609.07 hectares (73.8%) to 148.86 hectares (18%), while the farmland area increased from 135.65 hectares (16.4%) to 473.85 hectares (57.4%). The built-up area, which was previously only 7.65 hectares (0.9%) in 1984, expanded to 185.14 hectares (22.4%) in 2021 due to population pressure. Loss of biodiversity was identified as the most significant negative environmental impact of the Nyangongo wetland, as agriculture expansion and settlement have resulted in the loss of over 460.21 hectares of vegetation. The study's results suggest that to protect the Nyangongo wetland's resources, the County and National governments should declare it an Environmentally Sensitive Area. Furthermore, they should devise intervention strategies to regulate, restore, and relocate any land uses that are harmful to the wetland. In addition, promoting responsible use of the wetland is essential to ensure its preservation for future generations.