ABSTRACT
The rapid expansion of poplar plantation and its impacts on the wetland ecosystem have become a critical issue in West Dongting Lake ecosystem management. In the study, we explored the spatio-temporal characteristics of poplar plantation distribution in West Dongting Lake from 2000-2014 using Landsat imagery, topographic and hydrological data. Results showed that the area of the poplar plantation increased from 3233.5 hm2 to 10915.6 hm2 during the period of 2000 to 2011 (i.e. mean growth rate was 698.4 hm2·a-1), and the highest growth rate happened during the period of 2004 to 2007 (1000.6 hm2·a-1). Then, from 2011 to 2014, the expansion rate recorded a net loss, with the total poplar plantation area decreasing to 10153.1 hm2 in 2014. Reed marsh, open water and mudflat, and wet meadows contributed to the expansion of poplar plantation, which accounted for 41.8%, 37.0% and 21.2%, respectively. Failure policy incentives, as well as the market need for economic interests were the key drivers of the popular plantation expansion, and meanwhile, operation of the Three Gorges Dam that lowered down the flooding water level, as well as the sediment deposition within the lake bed offered favorable environment for popular tree growth. The project of "returning forest to wetland" after 2013 was the main reason for the decreased poplar plantation area in 2014.
