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Aims The mechanisms of plant community assembly are hypothesized to vary at different stages of succession. Here, we explore the local assemblage structure of a herbaceous plant community at its early stage of succession in a supratidal wetland. Specifically, we assess the role of Chinese saltcedar (Tamarix chinensis), the lone dominant shrub species, in shaping the spatial structure and species composition in the local plant community, after landscape alteration. Methods We used the multivariate trend-surface analysis for analyzing the spatial structure of the community composition. A null model was also used to detect potential biotic interactions between species. Statistical significance was derived from a permutation test by randomizing the presence-absence matrix and functional traits independently. Sensitivity analysis by randomly selecting 50 subplots and repeating the null model tests was also done. Finally, rank correlation analysis was used to study the relationship between effect sizes and distance to nearest T. chinensis individuals. Important Findings The herbaceous plant community was highly structured and shaped by the presence of T. chinensis. At local scale, two functional traits, plant height and leaf area, were found to be significantly convergent. Dispersal, environmental stress and interspecific competition played a trivial effect on the local community assembly. The facilitating effect of T. chinensis on the pioneering herbaceous plants, through acting as a wind shelter, was put forward as the dominant community assembly process.

Coastal wetland degradation and loss caused by intensive human activities, such as land reclamation and embankment, is a serious environmental problem. In this paper, we studied the succession of soil and vegetation in a coastal wetland dominated by Chinese tamarisk (Tamarix chinensis) community after the construction of a seawall. When the intertidal wetland became supratidal wetland, soil salinity firstly decreased and the gradient from sea to land became weaker. Next, the area of vegetation and plant species diversity increased, and the phenomenon of plant zonation disappeared. We reasoned that the rooted cause of soil and vegetation succession was the change in hydrological environment. Moreover, a Drivers-Pressures-State-Impacts-Response (DPSIR) model was used to analyze the relationship between human activities and coastal wetland. Using this model, we presented the potential problems that might arise in this wetland and predicted that vegetation flourishing was only a short term phenomenon but wetland degradation was the final consequences due to excessive exploitation of groundwater. At last, we proposed a few of operable measures as responses to these potential problems from the perspective of coastal management. (C) 2013 Elsevier Ltd. All rights reserved.