Mechanism of vegetation degradation at the ecotone of mountain forest and dry valley along upper reaches of Minjiang River

The upper reaches of Minjiang River are typical mountain eco-systems characterized by dry valley baseline.Its fragile eco-environment has seriously hindered the development of local society and economy.This paper selects the ecotone of mountain forest and dry valley as studying area at the upper reaches of Minjiang River on Xionger Mountain in Li County,and studies the degradation characteristics of vegetation.The degradation mechanic of the studying area ecosystem is explored based on the information of the investigation.According to the analysis,some measures are proposed to recovery and rebuild the ecology of studying area,hoping to provide some theoretical bases such as ecological succession theory in ecotone,vegetation restoration at the ecotone of mountain forest and dry valley and the management of composite ecosystem.