Squeezing Out Dune Plants: Coastal Erosion, Global Sea-level Rise, And The Loss Of Sand Dune Plant Habitats

In most circumstances, as coastlines erode, plant communitiesare displaced away from the ocean, unless blocked by a barrier, such asa cliff. In areas like Galveston Island, natural cliffs are not theissue, but development and non-native lawns block the plants'migration.

Creating models to explore low, medium, and high increases insea levels for Galveston Island, Feagin and colleagues found that thecombination of human-created barriers and sea level rise trapped plantsin a small zone, altering the plant population as well as the dunestructure.

Larger, sturdier plants -- late-succession species -- are themost important to preserve, yet these are the most likely species to belost. These plants are critical in the formation of dunes, bindingsediments, and reducing erosion, both in the long term and duringevents such as hurricanes. They also provide critical habitat forendangered animals such as the Kemp's ridley sea turtle (Lepidochelyskempii).

According to the scientists, in a low sea-rise scenario, plantcommunities fully developed over five years, but in cases of moderateand high sea level rise, plant communities were too stressed to grow inmany areas, leading to smaller dunes and an eventual breakdown of duneformation. In the higher water scenarios, the plant populations nolonger provided windblocks, elevated dune structures, or added to thesand and soil fertility.

On Galveston Island, "the loss of such species is alreadyoccurring, where sea oats (Uniola paniculata) have disappeared due to acombination of human-induced disturbance and climate change," say theresearchers.

All this means faster erosion and less protection for the people, animals, and buildings on Galveston Island.

Also appearing in the September issue of Frontiers:

- Researchers from the United States propose a way to encouragethe growth and size of Everglades tree islands in the review,"Maintaining tree islands in the Florida Everglades: nutrientdistribution is the key."

- Scientists discuss the Endangered Species Act in "Recoveryof imperiled species under the Endangered Species Act: the need for anew approach."