Population Structure and Dynamics of Remanent Myricaria laxiflora Downstream from the Three Gorges Dam

Myricaria laxiflora is an endangered shrub distributed around the Three Gorges Reservoir.To understand the impacts of the Three Gorges Dam on population dynamics and spatial pattern of remanent M.laxiflora,a permanent 40 m×40 m plot was established on a sandbar downstream from the dam.We analyzed the spatial pattern and population dynamics of M.laxiflora between 2008 and 2009 using univariate and bivariate Ripley’s K function.Our results demonstrated that M.laxiflora population regeneration was impacted,particularly in regards to small number of seedlings.The spatial pattern of M.laxiflora was significantly cor-related with spatial scales and individual size.Myricaria laxiflora was aggregated at most scales from 2 m to 20 m,with highest aggregation intensity at 9 m.With size increase,the aggregation intensity tended to decline.Population recruitment relied on the middle-sized individuals.We proposed that ex-situ conservation should be considered for M.laxiflora,and its population dynamics in natural habitats should be monitored over the long term.