Impact of human population on land degradation in former Lugari district, Kakamega county, Kenya
Wanyonyi, Raphael Wanjala
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The increase in human population has put tremendous pressure on natural resources. In Kenya, the growing human population is associated with an increase in developmental needs thus posing a threat to the land resource. This problem has been noted in the high potential areas of the country which support a large population seeking to fully exploit the land resources for their livelihoods and welfare. In Lugari district, human population has been increasing over the years and people have changed land use systems that have caused a reduced land cover and subsequent land degradation. The main objective of this study was to examine the relationship between the increase in human population and land degradation over a period of 38 years. Specific objectives of the study sought to: determine the extent of land degradation emanating from human activities, to assess the relationship between human activities on land use and land cover changes, and to assess and describe the types of land conservation and management measures that are practiced in Lugari district. To achieve these objectives, the study utilized four land-sat satellite imageries (1973 MSS, 1988 TM, 2003 ETM and 2010 ETM+) that were processed and analyzed using GIS software to produce GIS maps to detect and quantify land cover changes in Lugari district during the years: from 1973 to 1988, and 2003 to 2010. An accuracy assessment of the satellite imageries classification was conducted with field assessment points as reference data and an overall accuracy of 78.57% with a Kappa statistic of 0.75 were obtained. A household survey was also carried out in the study area to identify the activities that are responsible for land use changes and degradation. The data obtained from 100 households were subjected to Pearson’s Moment Correlation and Linear Regression analysis. The outcomes of the land use maps were used to evaluate the impact of human activities on the land and showed that major changes in land use land cover occurred mostly due to increased human activities between the period of seven years from 2003 and 2010. At 95% confidence level, the results indicate a significant relationship between an increase in human population growth / their activities and changes in land use practices resulting in land degradation. The growing trend of the population and consequent demand for food, energy, and area for settlement have considerably altered land use practices, reduced both plantation and natural vegetation cover stratum and severely caused land degradation at large. It was concluded that Lugari district has experienced a rapid growth in human population density during 38 years since 1973. In order to protect ground vegetation cover, the existing forests and vegetation in the area, there is need to encourage afforestation, reforestation, and social forestry programs at all levels in Lugari district. The study also proposes that there is a need to examine the carrying capacity, and to conduct the assessment of the land in the study area. Based on the findings, enforcement of the environmental laws for extra taxation must be introduced to discourage the residents who do deforestation, overgrazing, misuse of land and natural resources.