Effect of Land Use Land Cover Changes on Carbon Stocks of Rwenzori Mountains National Park, Western Uganda.

Abstract

Sustainable management of natural resources in Rwenzori mountainous areas requires an understanding of the current carbon stocks available and the nature of human-ecosystem interactions and local communities‘ perspectives regarding evolving changes. The study's aim was to investigate temporal and spatial changes in land cover and their contribution to the environmental stewardship of RMNP. This study characterized the dynamics of LULC in the Rwenzori Mountains National Park (RMNP), drivers of LULC changes, the current aboveground biomass and carbon stocks of the forest, and determined the effect of observed LULC changes on the park‘s carbon fluxes over a 30 year period. Satellite imagery for 1990, 2000, 2010, and 2020 were obtained from United States Geological Survey (USGS) website and analyzed to determine the LULC changes. A household survey, key informant interviews and focus group discussions were conducted to obtain the perceived drivers of LULC changes. Selected allometric equations were applied to assess the above ground biomass and carbon stocks of the forest in the park. Calculation of the Mean Squared Error (MSE), Prediction Sum of Squares (PRESS) statistic and Predicted R2 values of the selected equations was done to establish the most appropriate equation for biomass and carbon estimation. One way ANOVA was used to assess the variation in carbon stocks estimated for the various forest cover types. The effect of LULC changes on park‘s carbon stocks was determined by estimating the amount of greenhouse gases released or sequestered using the EX-ACT tool. Results show that there were expansions and reductions in the acreages of land covers between 1900 and 2020 in the RMNP i.e. there was a 3.6% reduction in the tropical high forest well-stocked; an increase in cultivated land; a reduction in the tropical high forest low stocked; and an increase in the grassland cover. The cultivation is mainly along the boundaries. Deforestation (33%), Agronomic practices (39%), and Population growth (17%) were perceived as key drivers of LULC changes. The TAGB was 668.495t/ha, and 50.625t/ha in the tropical high forest (THF)-High Stock, and THF-Low Stock respectively. The carbon stocks in the THF-High Stock were 327.245tC ha-1, and 27.898tC ha-1 in the THF-Low Stock. The study found significant variations (P <0.05) in above ground biomass and carbon stocks in the different forest cover types. There were both spatial and temporal changes in land use and land cover within RMNP, with loss of forest cover and cultivation along park boundaries being the most conspicuous. The major drivers of LULC change were mainly anthropogenic related factors with deforestation, population growth, & agronomic practices being the major drivers. The high AGB and carbon stocks in RMNP were indicative of a high potential for carbon sequestration, with the park being a net carbon sink over the 30 year period. The study recommends that UWA should tighten park boundary management by applying hybrid approaches including buffer zoning, electric fencing, thorn & stone hedges and support park bordering communities with sustainable and resilient agriculture and livelihood interventions to minimize encroachment on park resources