Forest pattern dynamics and landscape connectivity changes in the Manwan Basin after dam construction in the Lancang River, China

摘要

Regional habitat quality and landscape connectivity can be greatly impaired by dam construction and subsequent land-use changes. This study examined landscape pattern and connectivity changes in the Manwan Basin from 1974 to 2006 to quantify the effects of dam construction. Landscape pattern indices and kernel density estimation (KDE) were used to analyze forest pattern dynamics, while the probability of connectivity (PC) index was applied to evaluate landscape connectivity changes. The results showed that forest area decreased by nearly 20 %, while the number of forest patches increased more than sixfold from 1974 to 2006 in the Manwan Basin. During the study period, forest fragmentation mainly occurred in the western and northern parts of the Manwan Basin. Due to the changes in the forest landscape pattern, landscape connectivity decreased by an average of 54.74%. In addition, we detected changes to key stepping-stone patches by calculating the percentage importance of each resource patch. The results showed that 300.38 km~2 of high-importance forest patches transformed to medium-and low-importance patches from 1974 to 2006.