Coastal Dune Ecology
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- Beach
- Fore Dunes
- Back Dunes
- New Ecosystem
The first part of the coastal dune ecology, the beach, sits directly in front of the dune system. A self-sustaining beach, one not subject to erosion problems, typically has a noticable wet and dry section. The wet portion of the beach changes thoughout the day with the ebb flow of the tide. The dry beach area stays dry from the normal ebb and flow of the tide. As sand accumulates on the dry section, a combination of wind and weather start the dune construction process by blowing the sand further inland.
Somewhere along the way, natural or human placed objects begin to serve as sand stumbling blocks, collecting the blowing sand around them. Over time, the mound of sand begins to grow, giving rise to the fore dunes begin forming. Because fore dunes are the beaches first defense during storms, they support the least amount of plant life such as beach grass.
The larger back dunes situated behind the fore dunes often have a higher density vegetative cover. In a well developed coastal dune system the back dunes set a quasi-boundary between the primarily sandy coastal dune ecosystem and a new and separate ecosystem.
As the dune system moves from the fore dunes toward the back dunes, with their increased vegetation, the ecosystem becomes more complex, supporting a larger amount of plant and animal species.
The transition from the back dunes to the next ecosystem could take one of many forms depending on the location. In some areas sandy beaches are replaced by a marsh or lagoon, or even in the case of dunes on barrier islands, the other side of the ocean. Dunes located in mountainous regions commonly transition to the cliff rocks.
© 2003. Patricia A. Michaels.