Effects of vegetation change and land use/land cover change on land surface temperature in the mara ecosystem

Abstract

Human interactions with the environment are identified as one of the leading causes of climate change and variation. Modification, conversion and maintenance of land cover are all forms of anthropogenic interactions with the environment that result in a variety of vital changes to the environment that either positively or negatively feedback to the environment and climate. The identification and monitoring of these Land Use/ Land Cover Changes (LULCC) is therefore important since changes in land cover, occasioned more often than not by anthropogenic land use, alter land-atmosphere interactions upon which ecosystem services rely thus resulting in climate change and variation. Land Surface Temperature (LST) is a property of the land surface and refers to the temperature of the interface between the earth’s land surface and the atmosphere. It is therefore an important variable in landatmosphere interactions and a climate change indicator which varies over space and in time as a function of vegetation cover, surface moisture, soil types, topography and meteorological conditions. Normalized Difference Vegetation Index (NDVI) is a numerical indicator derived from the Visible (Red) and Near Infrared (NIR) bands of the electromagnetic spectrum used in remote sensing to assess the concentration of green leaf vegetation and plant phenology. It is also an accepted and widely used parameter in characterization and assessment of vegetation change. This study uses a remote sensing approach in one of the most ecologically rich and diverse ecosystems to investigate the effect of Land Use/ Land Cover Change and in particular vegetation change on Land Surface Temperature (LST). The study area is in the Mara ecosystem located in South Western Kenya. LANDSAT satellite images for 1985, 1995, 2003 and 2010 were used to derive NDVI and LST. We found that human related Land Use/ Land Cover Change (LULCC) in the form of conversion of land for cultivation purposes has been and is taking place around the Maasai Mara National Reserve (MMNR). We also found that a negative correlation exists between LST and NDVI thus indicating that with decrease in vegetation cover and conversion to cultivated land, there is increase in Land Surface Temperature (LST).