Biological resources of the Louisiana coast: Part 1. An overview of coastal plant communities of the Louisiana gulf shoreline

Abstract

Plant communities are vital to maintaining diverse coastal and estuarine ecosystems in Louisiana's Deltaic and Chenier Plains. These plant assemblages provide not only primary productivity but also structural stability to terrestrial (supratidal) and aquatic (inter- and subtidal) substrates, thereby creating diverse habitats for many important estuarine and coastal fauna. Barrier islands are an important and dynamic component of the coastal landscape with plant assemblages ranging from terrestrial dune habitats to swales and intertidal back-barrier marshes. Barrier islands provide protection for bayward submersed aquatic vegetation and interior salt marsh plant assemblages by reducing wave energy and allowing shallow water habitats to exist over large expanses. Further landward, vast expanses of brackish, intermediate, and fresh marsh habitat make up Louisiana's extensive coastal marsh ecosystems. Louisiana's barrier islands have migrated landward and decreased in size through time as overwash events have become more frequent in this sand-deficient system. In the absence of restoration efforts to bring sand resources back into the system, island degradation will result in significant reductions in habitat diversity and loss of protection of mainland resources. This article provides an overview of Louisiana's coastal plant communities, emphasizing the key role of barrier island plant communities in the deltaic landscape. The companion article focuses on the animal resources of the Louisiana Gulf shoreline.