Ecological service is the benefit that humans obtain from the ecosystem and the relationship between these services, human welfare and the monetization of ecosystem services Land use change is a direct manifestation of human effects on the natural environment, To ensure effective management and utilization of ecological services for sustainable economic development in the region, there is a need for an in-depth integrated study of spatio-temporal environmental changes using remote sensing and GIS Therefore this study assessed the effects of Environmental changes on ecological services around Erinle/Owalla Reservoir, Osun State, Nigeria. Data were obtained from both primary and secondary sources, the primary data generated on ecological biomes within the study area, while the secondary data used multi-satellite imageries: Landsat 5 TM 1986, Landsat 7 ETM+ and Landsat 8 OLI and TIRS. The images were digitally processed using Envi 5.0 and Arcmap 10.2 software using maximum likelihood classification algorithm. Five classes landuse/landcover were identified (Settlement, Waterbody, Forest, Farmland, and Outcrop). Environmental data (Rainfall, Temperature and Relative humidity) were extracted from the images. There was a gradual decrease in farmland, 55.55% in 1986, 42.66% in 2006, and 22.29% in 2016 respectively. While the highest temperature for the landuse/landcover was 42.660C in 2016, 34.530C in 2006 and 30.420C in 1986 respectively. The lowest temperature was experienced in the year 1986 (21.060C). Direct market value of ecological services was determined using Ecosystem Service Valuation method. The highest Direct Market value of ecological services in the study area was 0.32$/ha/year in 2016, 0.31$/ha/year in 2006 for water body and 0.14$/ha/year in 1986 for settlement. The cumulative percentage of the ecosystem service are 0.0029 in 1986, 0.0038 in 2006, and 0.0039 in 2016. The temporal changes in the ecosystem service are strong indications of the environmental effect of human activities in the study communities. There must be proper maintenance of these ecological services involving all stakeholders (Government at all levels, NGO’s and private individuals) and policies made to guide them.
Key Words: Ecological Services, Remote Sensing, Ecological Biomes, Satellite Images and Ecosystem Service Valuation