Journal Article

Consumer Control of Salt Marshes Driven by Human Disturbance

BERTNESS, MARK D., SILLIMAN, BRIAN R.

2008

Overview

Salt marsh ecosystems are widely considered to be controlled exclusively by bottom-up forces, but there is mounting evidence that human disturbances are triggering consumer control in western Atlantic salt marshes, often with catastrophic consequences. In other marine ecosystems, human disturbances routinely dampen (e.g., coral reefs, sea grass beds) and strengthen (e.g., kelps) consumer control, but current marsh theory predicts little potential interaction between humans and marsh consumers. Thus, human modification of top-down control in salt marshes was not anticipated and was even discounted in current marsh theory, despite loud warnings about the potential for cascading human impacts from work in other marine ecosystems. In spite of recent experiments that have challenged established marsh dogma and demonstrated consumer-driven die-off of salt marsh ecosystems, government agencies and nongovernmental organizations continue to manage marsh die-offs under the old theoretical framework and only consider bottom-up forces as causal agents. This intellectual dependency of many coastal ecologists and managers on system-specific theory (i.e., marsh bottom-up theory) has the potential to have grave repercussions for coastal ecosystem management and conservation in the face of increasing human threats. We stress that marine vascular plant communities (salt marshes, sea grass beds, mangroves) are likely more vulnerable to runaway grazing and consumer-driven collapse than is currently recognized by theory, particularly in low-diversity ecosystems like Atlantic salt marshes.

• Publisher: Blackwell Publishing Inc,Blackwell Publishing, Inc,Blackwell,Blackwell Publishing Ltd
• Subject: Animal and plant ecology / Animal, plant and microbial ecology / Animals / anthropogenic activities / Applied ecology / Aquatic ecosystems / Biological and medical sciences / Brackish / Brackish water ecosystems / cascadas de trophic / Coastal ecology / Coastal ecosystems / conservación de pantano de sal / Conservation / Conservation biology / Conservation of Natural Resources / Conservation of Natural Resources - methods / Conservation, protection and management of environment and wildlife / consumer control / control de consumidor / Coral reefs / Die off / Ecologists / Ecosystem management / Ecosystems / Essay / Food Chain / Fundamental and applied biological sciences. Psychology / Geese / Government agencies / Grasses / Grazing / Horses / Human Activities / human impacts / Human influences / humans / impactos humanos / Lentic systems / macroalgae / managers / Mangroves / Marine / Marine ecology / Marine ecosystems / Marshes / methods / NGOs / Nongovernmental organizations / Parks, reserves, wildlife conservation. Endangered species: population survey and restocking / Plant communities / Plants / Rodentia / Saline water / salt marsh conservation / Salt marshes / Snails / Synecology / Theory / trophic cascades / Wetland ecology / Wetlands