Rooting for resilience: Investigating the success of seagrass restoration methods

Seagrasses generate vital ecosystem services to coastal communities, whilst also protecting marine biodiversity. Despite their significance, seagrass ecosystems face a plethora of threats from both anthropogenic and natural sources, causing a 20 % loss of seagrass area over the last century. To combat this, numerous restoration methods exist for seagrass habitats globally, with varying degrees of success. Through a comprehensive systematic review and subsequent meta-analysis, this study illustrates the varying success rates of different transplant and seed-based restoration methods over differing timescales. Accounting for varying timescales, results showed that restoration method had a significant effect on success rate (χ2= 28.69, df=9, p < 0.001), with bundles having the most effective success rate overall (77.98 % ± 11.59) and outplanting having the lowest (17.98 % ± 26.14). A linear regression model showed approximately 10 % of variance in restoration success was attributed to timeframe. The varying success rates of restoration methodologies can be attributed to a myriad of causes, including environmental conditions, disturbance events and initial survival. Future restoration should focus on using site-specific restoration methods, considering timeframe, alongside potential threats, and environmental conditions.