Bio-geomorphic impacts of invasive species in coastal wetland ecosystem: a review

The tidal wave is a major vector of seed dispersal in salt marshes. Seed movements driven by tidal waves along elevation gradient generate seed flow. Land reclamations in salt marshes change seed dispersal pattern by disturbing tidal wave. In the present work we observed the seed flow／flux of Suaeda salsa in low, mid and highmarshes, and established a quantitative framework to address seed dispersal pattern and pattern response to land reclamation projects. Suaeda salsa seeds in low and middle marsh zones were found to be transported landforward and seaforward by tidal wave. The upside of low marsh zones were the source of seed flow and the downside of middle marsh zones was the sink of seed flow. Land reclamations in high marshes shifted pattern of seed dispersal in all regions of salt marshes. This study therefore identified the potential threats of seed dispersal change to downside of middle marsh zones: seed flow changed from sink to source resulting in net seed outflow.