It is a premise in ecology that undisturbed ecosystems are relatively stable, and hence that sudden changes in ecosystem are likely to result from external, mostly human influences. Johan van de Koppel, Daphne van der Wal, Jan P. Bakker, and Peter M. J. Herman present a combined theoretical and empirical study indicating that natural processes within salt-marsh ecosystems can lead to ecosystem destruction. They model salt-marsh development based on the mutually enforcing interaction between plant growth and accumulation of sediment.

Observations from Dutch salt marshes confirm the model predictions that at first, plant-sediment feedback buffers the salt marsh from the strong physical gradient that characterizes the marine-terrestrial boundary, and improves plant growth along the gradient. However, as a consequence of this process, the edge of the salt marsh and the adjacent intertidal flat becomes increasingly steep and vulnerable to wave attack. Disturbance due to for instance a storm, may induce a cascade of vegetation collapse and severe erosion on the cliff edge, leading to salt-marsh destruction. Seawards of this cliff new pioneer vegetation can develop, leading to rejuvenation of the salt marsh.

The study shows that on short timescales, natural processes improve the functioning of salt-marsh ecosystems. On longer timescales, however, the same processes increase ecosystem vulnerability and may lead to collapse of salt-marsh vegetation.

'"/>

Contact: Carrie Olivia Adams
coa@press.uchicago.edu
773-834-0386
University of Chicago Press Journals
2-Feb-2005

Page: 1
Related biology news :

1. A thesis of the UGR analyses more than 20-million-year-old vegetation to study climatic evolution
2. Fires from the past predict the vegetation of tomorrow
3. Increased dampness causes vegetation change
4. Deep sea algae connect ancient climate, carbon dioxide and vegetation
5. As world warms, vegetation changes may influence extreme weather
6. Taking the piste out of Alpine vegetation
7. Introduced foxes transformed vegetation on Aleutian Islands from lush grasslands to tundra
8. Census of Marine Life historians detail collapse of bluefin tuna population off northern Europe
9. Antarctic marine explorers reveal first biological changes after collapse of polar ice shelves
10. Climate changes, Cod collapse have altered North Atlantic ecosystems
11. Ongoing collapse of coral reef shark populations