Assessing land use change and its impact on ecosystem services in Khulna conurbation

Abstract

Bangladesh is one of the most densely populated countries in the world with a population of 165 million which is 2.11% of the world population. The population increased from 14.1 million to 165 million from 1981 to 2020.To fulfill the extra need, each year 82,900 ha of cropland and 221 ha of arable land are changed over into other land employments.Land-use changes are intense in southwest seaside areas of Bangladesh.56% of the rural place where there is southwest waterfront Bangladesh was changed over to other land use classifications (water bodies, desolate land, and vegetation). Khulna Conurbation is the economical hub of the Khulna district which is also affected by the land-use changes. Generally, Conurbation is defined as the extended urban area through which sub-urban areas are merged with the center of the city. In this research, the land-use change of Khulna Conurbation has been dissected utilizing Landsat images from 1987 to 2018 through GIS analysis and its effect onthe ecosystem hasbeen decided with the assistance of auxiliary information. The major types of land use in Khulna Conurbation are settlements followed by vegetation, agricultural, wetland, and river. The present study showed that in Khulna Conurbation, build-up territory expanded from 1343ha to 4332 ha (223%)from 1987 to 2018 because of a quick improvement in the city, particularly in the north-western and centerpiece of the city. On the contrary, vegetation area decreased from 5716 ha to 3597 ha (37%); Water Bodies are decreased from 940 ha to 172 ha (82%); River areas are also decreased from 1987 to 2018 from 784 ha to 692 ha (12%) during this period. Because of the reduction of vegetation area and water bodies, the provisioning services like the production of rice, fish, and livestock is decreased. People living in agriculture and fisheries have chosen other professions like auto-rickshaw& easy bike driving, grocery shop, saw miller, and other small businesses. These land-use changes put a critical effect on the different ecosystems. From 1987 to 2018, the ecosystem service values for all land use categories were negative except for urban build-up which is 2485 million BDT.The largest amount of declination was observed in the case of vegetation whichwas about 1014 million BDT.Land-use change hadan impact on the regulating services likethe natural drainage system of Khulna Conurbation which resulted in severe waterlogging problems. Due to the rapid urbanization and high population growth rate, the few wards of the city faced serious groundwater depletion. Proper district and Upazilla level land use plans should be implemented to maintain the sustainable growth of the city and enhancement natural ecosystem services. Besides steps should be taken to make awareness among the local people.