Seagrass grows in shallow, sheltered, and soft-bottomed coastal waters and estuaries. More than 60 species of seagrasses exist worldwide and play important roles in shallow marine ecosystems (Björk et al. 2018:16).
Their main protective benefits are wave attenuation and sediment trapping, thus reducing the risk of soil and coastal erosion, particularly after heavy rainfall. Seagrass meadows are nurseries for young fish, who feed in the nutrient-rich waters while hiding from predators.
In terms of environmental benefits, seagrass is a powerful carbon sink and important habitat (home to 40 times more species than bare sand). Seagrass is also a food source (seeds) and used as material for roofing, mattresses and traditional medicine (ibid:17).
Seagrass restoration and rehabilitation require scientific and technical advice. Specific actions may include efforts to improve water quality and light exposure, planting of seedlings or seeding areas for restoration, eliminating the causes of seagrass decline, raising awareness of the value of seagrass and inclusion in coastal management plans (ibid, 26-34)
Seagrass meadows are rated the third-most valuable ecosystem on a per-hectare basis, only preceded by estuaries and wetlands. They have undergone a worldwide decline, primarily as a result of local pollution along coastlines.
The plants grow best in clear and gently moving water. They require light and nutrients for growth. Run-off of wastewater and sediments reduces the light, often as a side-effect of excessive algae growth (which steal the light).
Protecting seagrass meadows by restricting run-offs, pollution and direct physical disturbances by human activity is therefore the starting point, and usually the single most cost-effective measure.
If there is - or has been - seagrass in your area, follow the guidance below, in the section titled "The Process".