Newswise — Results from a new study suggest that the establishment of woody species in flotant marshes leads to higher overall density. This study is published in the latest issue of the Journal of Coastal Research.

Freshwater marshes are ecologically and commercially important ecosystems covering approximately 383,000 ha along Louisiana's coast. Floating marshes once covered as much as 100,000 ha in Louisiana. Marshes provide a critical habitat for numerous species and buffer the rapidly subsiding coastline from storm and wave action that can exacerbate erosion and sediment loss. Despite the numerous goods and services they provide, these marshes are being lost at an alarming rate due to anthropogenic and natural factors.

The dynamics of flotant communities are largely unstudied. To study the potential effects of woody species invasion on herbaceous community characteristics, the study researchers compared open herbaceous marsh, sparse scrub-shrub, and dense scrub-shrub thickets at Jean Lafitte National Historic Park and Preserve in coastal Louisiana.

They found that species richness and composition differed significantly among the three marsh types. Herbaceous communities lacking shrub canopies had the lowest richness and were dominated by emergent species typical of freshwater marshes. Richness and composition of sparse scrub-shrub thickets were intermediate between open marsh and dense thickets. The latter had the greatest species, with assemblages more typical of forest understories, as well as aquatic species that occurred where holes in the floating mat formed. Overall, the establishment of woody species drove changes toward a combination of woodland and aquatic assemblages.

To read the entire study, click here:

Journal of Coastal Research is the bimonthly journal of The Coastal Education and Research Foundation (CERF). To read more about the society, visit

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Journal of Coastal Research