Spatial and Temporal Changes of Homegarden Land Use as a Tree Resource Outside Forests in Upper Mahaweli Catchment of Sri Lanka: Biophysical and Socioeconomic Determinants of Major Changes

Tree rich homegardens as Tree Resources Outside Forests (TROF) consider as one of the major land use systems in the Upper Mahaweli Catchment (UMC). Homegardens play a significant role in reducing negative impacts and protecting the catchment in areas where lack of forest cover. The main objective of this study was to analyze spatial and temporal changes of homegarden land use of UMC and to analyze determents for the major change. A multi-temporal spatial assessment was carried out using geospatial tools and techniques utilizing Landsat images acquired in 1992 and 2017. Eight prominent land uses in the catchment were classified to prepare land use maps and for change detection. Determinants for the major land use change was assessed by employing a multiple regression model using environment, spatial, demographic, and socioeconomic variables. Results revealed that forest area remains the same for the past 25 years in UMC while area under homegardens has been increased by 60%. The major land-use change was the other agricultural crops-based land use into homegardens. Elevation, proximity to main road, proximity to town centers, population density, education level, and poverty were significant determinants for the change. The negative and significant (p<0.01) relationship between land use change from other agricultural crops into homegardens and elevation implies that there is a low tendency for change into homegardens in higher elevations. Therefore, effective measures should be taken to control unsustainable land uses at higher elevations and incentives should be introduced to enhance the quality of homegardens to maintain the sustainability of the UMC.