Seagrass Success: 900cm² Thalassia PUs Restore Coastal Habitats

This peer-reviewed article documents a highly successful seagrass restoration project using propagation units (PUs) of native Thalassia testudinum, achieving rapid coverage and ecosystem recovery in scarred coastal habitats. Each PU covers 900 cm², harvested from donor sites with minimal impact—scars backfilled using 30-60 kg biodegradable hessian bags filled with sand to promote edge recolonization. High PU volume ensured robust root-shoot-microfauna connections, preserving active rhizome meristems and short shoots for superior growth and survivorship. Sourcing from multiple donor sites boosted genetic diversity, critical for resilience against disturbances. Post-planting, PUs expanded coverage by 300-500% within months, demonstrating asexual propagation efficacy. The method's success stems from mechanical stability, biological integration, and scalability: detailed protocols include donor site selection (healthy, diverse meadows), PU extraction (shallow cuts to minimize trauma), transport in seawater, and planting at 20-30 cm spacing in prepared beds. Monitoring showed 85-95% initial survival, with full meadow integration by year two, enhancing biodiversity, fish habitats, and sediment stabilization. Backfilling accelerates natural recovery, reducing erosion risks. This approach offers practitioners a field-tested, low-cost alternative to seed methods, with quantifiable metrics for replication. Insights include optimizing harvest timing (post-growing season), density effects on competition, and integration with propeller scar remediation. Applicable to regenerative coastal management, it supports self-sufficiency by restoring nutrient cycling and ecosystem services, providing a blueprint for similar subtropical environments with proven, mechanistic outcomes.