The spatial – Temporal Relationship between Land Use / Land Cover changes and Microclimates in the Kigezi Highlands Region, Uganda

Abstract

The current study was carried out to establish the spatial and temporal relationship between land use / land cover (LULC) changes and highland microclimates in Uganda, with Kabale district as the study area. The objectives of the study were; to quantify all LULC changes that have taken place since 1990, establish the variations in rainfall and temperature over the same period and establish if there is significant (α=0.05) covariation between the changes in LULC and those in the climate variables. Landsat images for the years; 1995, 2003, 2011, 2016 and 2021 were acquired from the United States Geographical Survey (USGS) website (https://earthexplorer.usgs.gov/) and reduced to the geographical extent of Kabale district. These were classified to develop land cover maps with classes; Open Water, Developed Area, Wetland, Agricultural Land, Forest and Bare Land. Transition matrices were developed to explain the changes from one class to another over the years. Using ArcMap software, 300 random points were picked from the area of interest and overlayed on classified rasters as well as rainfall and temperature geotiff images to extract the underlying data. This data was acquired from the Makerere University Earth Observations Lab. The data variables were; the LULC class at the time, the annual rainfall recorded that year, and maximum temperature for the year. For each period, an analysis of variance was run to establish if the mean rainfall / temperature for the period was dependent on the LULC class the data collection point fell in. Results of the study revealed that between 1995 and 2003, there was a reduction in wetlands (44.1%) and forests (62%), with increasing agricultural land (15.2%) and developed area (2.8%), a trend that was reversed between 2003 and 2021. At α=0.05, rainfall increased insignificantly (P=0.456), while temperature increased significantly (P<0.01) over the period. Different LULC recorded significantly different (α=0.05) rainfall and temperature with all P-values less than 0.05 (appendices 2 and 4). Wetlands and open water recorded the most rainfall and lowest temperature, while developed area and forest had the least rainfall and warmest temperatures. From the study results, it was established that changes in LULC have contributed significantly to the emergence of current microclimates. Therefore, efforts to establish green spaces and restore degraded natural ecosystems are needed in curbing the impacts of the changing climate, especially heat waves.