HISTORICAL WETLAND CHANGE DETECTION FOR SUSTAINABLE MANAGEMENT: A CASE OF LUKANGA SWAMP, ZAMBIA

Abstract

Lukanga is one of the listed Ramsar Sites in Zambia, which contains a rich biodiversity and a highly productive ecosystem. However, the valuable landscape has undergone a radical change in its form over the decades. This study uses past and recent satellite data to evaluate the typical land cover change over the decades. The objective of the study was to investigate land use land cover changes (LULCC) in Lukanga Swamp from 2000 to 2023. The study utilized satellite images from the United States Geological Survey (USGS), specifically Landsat images from 2000, 2013, and 2023. The data was processed, analyzed, and presented. Image pre-processing was used to correct distortions, and Erdas Imagine 2014 was used for enhanced techniques. Both pre-classification and post-classification change detection approaches were used to assess the change in the results from 2000 to 2023. Furthermore, NDVI and NDWI analysis were implemented to assess the change scenario. The maximum likelihood supervised classification technique was performed to create the signature class of significant land cover category (deep water, shallow water, forest, irrigated farmland, grassland and settlement/ bare soil). After ensuring satisfactory accuracy value for each classified image, a detail post-classification change detection analysis was executed. The results of this study have shown a decrease in the classes of deep water, shallow water and forest areas by 9.4 %, 25.5% and 1.5%, respectively, over the 23-year period. The results have also shown an increase in the land use land cover classes categories of irrigated farmland land-irrigated, grassland, and settlements/bare soil by 0.28 %, 0.024%, and 36.3 %, respectively. The study also showed NDVI and NDWI values for 2000 and 2023. The maximum NDWI values were 0.32 and 0.15 for 2000 and 2023, respectively, indicating more water bodies or higher water content in 2000. Vegetation cover status was determined using NDVI values, with values of 0.61 and 0.45 in 2000 and 2023, respectively. A 2023 NDVI of 0.45 suggests vegetation presence despite a slightly lower density than in 2000. The study area faces biodiversity loss, soil and forest degradation, land scarcity, and food shortages due to LULC change. Adequate policy and strategy are needed to mitigate these impacts and improve wetland protection, restoration and management.