The future of seagrass meadows

• Published in: Environmental conservation 2002-06, Vol.29 (2), p.192-206
• Main Author: Duarte, Carlos M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Aquaculture; Biological and medical sciences; Climate change; Climate effects; Coastal ecosystems; Coastal zone; Coastal zone management; Coasts; conservation; Conservation, protection and management of environment and wildlife; Earth sciences; Earth, ocean, space; Ecosystem management; Ecosystems; Environmental policy; Environmental protection; Eutrophication; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects; global change; Legislation; Littoral ecosystems; Marine; Marine ecology; Marine ecosystems; Meadows; Paleobotany; Paleontology; perspectives; Sea level rise; seagrass; Sediments; status; Trends; Tropical environments
• ISSN: 0376-8929; 1469-4387
• DOI: 10.1017/S0376892902000127

Seagrasses cover about 0.1–0.2% of the global ocean, and develop highly productive ecosystems which fulfil a key role in the coastal ecosystem. Widespread seagrass loss results from direct human impacts, including mechanical damage (by dredging, fishing, and anchoring), eutrophication, aquaculture, siltation, effects of coastal constructions, and food web alterations; and indirect human impacts, including negative effects of climate change (erosion by rising sea level, increased storms, increased ultraviolet irradiance), as well as from natural causes, such as cyclones and floods. The present review summarizes such threats and trends and considers likely changes to the 2025 time horizon. Present losses are expected to accelerate, particularly in South-east Asia and the Caribbean, as human pressure on the coastal zone grows. Positive human effects include increased legislation to protect seagrass, increased protection of coastal ecosystems, and enhanced efforts to monitor and restore the marine ecosystem. However, these positive effects are unlikely to balance the negative impacts, which are expected to be particularly prominent in developing tropical regions, where the capacity to implement conservation policies is limited. Uncertainties as to the present loss rate, derived from the paucity of coherent monitoring programmes, and the present inability to formulate reliable predictions as to the future rate of loss, represent a major barrier to the formulation of global conservation policies. Three key actions are needed to ensure the effective conservation of seagrass ecosystems: (1) the development of a coherent worldwide monitoring network, (2) the development of quantitative models predicting the responses of seagrasses to disturbance, and (3) the education of the public on the functions of seagrass meadows and the impacts of human activity.