GIScience & Remote Sensing (Dec 2022)
Monitoring ecological and environmental stress patterns over the past two decades in the Mekong River basin
Abstract
Among the most biodiverse environments in the world, the Mekong River Basin has experienced extensive socio-economic development in the past few decades resulting in land use change and associated ecological and environmental stresses. To assess possible impacts on sensitive ecosystems and their services in the Lower Mekong River Basin (LMB), we examine spatial and temporal changes in forest community extent, as well as tree density and canopy coverage, in relation to carbon uptake and climate change. We employed the Mann–Kendall test to identify regions of likely significant ecological and environmental change within forest ecosystems. We developed a new approach to eliminate the classification of false positives and false negatives. We quantified the annual rate of ecological changes using Sen’s slope. Ordinary Least Squares (OLS) regression analysis was performed to analyze the impact of tree and leaf density changes on the regional environment, particularly with regard to net primary productivity (NPP) and surface temperature trends. Across the LMB, a total of 2.81% of forest extent has been lost. Cambodia experienced the most prominent forest loss among all countries, while Thailand and Myanmar had net forest gain. NPP trends were starkly divergent from the north to the south and declined across the majority of northern Laos. The LMB region experienced increasing trends for both daytime and nighttime temperatures except for small portions of Thailand and Vietnam. An annual 0.0876°C increase in surface temperature can be expected for every 1% decrease in tree density in forest degraded regions, while a substantial annual carbon productivity increase can be expected in reforested regions. In addition, the effectiveness of policy enforcement at the government level is critical for reforestation in LMB.
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