Abstract

Ecological restoration will be crucial in halting the degradation of coastal marine habitats. This will depend on maintaining an adequate supply and survival of propagules, which are mostly fruits, seeds, viviparous seedlings, zoospores, or larvae for the primary habitat-forming taxa of coastal marine environments. The chance of propagule survival-and hence, the effectiveness of restoration efforts-depends on species- and context-specific knowledge to inform decisions regarding the most suitable approaches. The primary habitat-forming taxa of the six coastal marine ecosystems-mangrove forests, tidal marshes, sea grass meadows, kelp forests, coral reefs, and bivalve reefs-are reviewed here in a brief overview. In order to restore a number of these ecosystems, propagules have long been used. Sometimes this is because they are easy to employ (for instance, planting mangrove propagules), and other times it is because we may learn from other applications (for example using knowledge of oyster culture to restore bivalve reefs). Propagules have not yet been extensively exploited in other habitats, such as seagrass meadows, kelp forests, and coral reefs, but there is strong evidence that they can be. The majority of restoration projects have employed quite straightforward procedures like manual collecting and direct planting or seeding.

A stage in which propagules are raised in nurseries or aquariums until they reach a size or age at which they are viable before being planted or released onto the place to be restored is one of the most advanced strategies used in some approaches. Other methods involve less intervention and instead concentrate on creating environments that will encourage growth from naturally scattered propagules (such as restoring hydrological conditions to facilitate mangrove recruitment). Future methods could use the opportunities offered by technology and use information from other sectors, like genetics and agriculture. Understanding the significance of propagule quality and effectively using models to help develop restoration techniques for testing would probably also provide insights. Deeper collaborations between scholars and practitioners will test and create better techniques, allowing us to grow and learn from one another. Propagules provide a number of viable ways to increase coastal marine restoration efforts and contribute to global goals.