Land Use Land Cover Changes and their Effects on Food Security

Abstract

In the last four decades the emergence of new technologies and effects of rapid population growth around the globe have necessitated a tremendous shift by managers and planners on how to tackle land use and land cover (LULC) changes. Geospatial technologies have been used extensively in many areas of the world for generating valuable information on the forest cover, vegetation type, land use change detection and general environmental monitoring. Kiambu County is one of the most affected counties in Kenya by LULC changes due to its proximity to the capital city (Nairobi), good climate, fertile soils and improved infrastructure. This paper analyses the effects of LULC change on food security in Kiambu County and determines the main drivers of LULC changes using geospatial technologies. Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM+) satellite images together with other data-sets were used. Satellite images for the years; 1984, 1993, 2002 and 2013 were applied in the time-series analysis of LULC. Digital image analysis was carried out through supervised classification using ERDAS Imagine 2011 by defining the training sites on the respective images. The classes mapped were agricultural land, forests, built-area/urban, water body, wet land, grassland and bare land/rock area. The overall accuracy was in the range of 89.70% to 90.71%. The results obtained showed that Agricultural land reduced over the whole period of study from 39.69% to 15.75% which is an indication that the County is food insecure considering that the population also grew at similar rates. It is also evident that the built-area/urban increased tremendously over the same period, from 1.88% to 33.50%, showing high demand for houses. A decrease in grassland, Forest, water body and Bare-land/Rocky areas was also observed. The application of geospatial technologies to analyze LULC and related effects was clearly demonstrated.