All scales: All scales: Local scale: Local scale: Local scale: Local scale: Damaged or No discernible lasting Temporary loss of Temporary loss of Loss of 50% to None Localised – degraded seagrass impact on seagrass up to 10% of a local between 10 and 20% 100% of a local seagrass loss meadow is health. meadow, but no of a single seagrass seagrass meadow (even improved or discernible impact meadow, with full for more than 5 permanently) is rehabilitated. Local scale: on dependent recovery likely within 3 years. If the activity unlikely to result in Frequent, species as other years. ceases, natural extreme Seagrass habitats disturbance nearby meadows recovery may occur consequences on are identified, over a small are able to meet Regional or within 10 years. the overall value of managed, percentage of the their needs. The widespread scale: seagrass, unless More stable monitored, total meadow area local meadow is Temporary loss of up Loss of 20% to the meadow is species or protected and (such as boat likely to recover to 10% of a critical 50% of a single critical or part of a meadows conserved. propeller damage) within 1 year. meadow or multiple seagrass meadow, larger scale, (such as which results in a meadows. Full with full recovery cumulative loss. shallow Zostera, Water quality is small section of the Regional or recovery is likely within likely within 3 Cymodocea, improved to ensure meadow being widespread scale: 1 year. years. Regional or Halodule, seagrass damaged but does No discernible widespread scale: Thalassia) requirements are not impair its overall lasting impacts on Regional or Loss of more than being met health or ecosystem a critical meadow, widespread scale: 20% of a critical function. or on multiple Temporary loss of meadow, or of meadows. Impacts 10% to 20% of a multiple meadows, are confined to a critical meadow, or for more than 5 single non-critical of multiple years. Even if the meadow. meadows. Full activity ceases, recovery is likely natural recovery is within 3 years. unlikely within 10 years.
More stable species or meadows (such as shallow Zostera, Cymodocea, Halodule, Thalassia) All scales: Damaged or degraded seagrass meadow is improved or rehabilitated. Seagrass habitats are identified, managed, monitored, protected and conserved. Water quality is improved to ensure seagrass requirements are being met All scales: No discernible lasting impact on seagrass health. Local scale: Frequent, disturbance over a small percentage of the total meadow area (such as boat propeller damage) which results in a small section of the meadow being damaged but does not impair its overall health or ecosystem function. Local scale: Temporary loss of up to 10% of a local meadow, but no discernible impact on dependent species as other nearby meadows are able to meet their needs. The local meadow is likely to recover within 1 year. Regional or widespread scale: No discernible lasting impacts on a critical meadow, or on multiple meadows. Impacts are confined to a single non-critical meadow. Local scale: Temporary loss of between 10 and 20% of a single seagrass meadow, with full recovery likely within 3 years. Regional or widespread scale: Temporary loss of up to 10% of a critical meadow or multiple meadows. Full recovery is likely within 1 year. Local scale: Loss of 50% to 100% of a local seagrass meadow for more than 5 years. If the activity ceases, natural recovery may occur within 10 years. Loss of 20% to 50% of a single seagrass meadow, with full recovery likely within 3 years. Regional or widespread scale: Temporary loss of 10% to 20% of a critical meadow, or of multiple meadows. Full recovery is likely within 3 years. Local scale: None – Localised seagrass loss (even permanently) is unlikely to result in extreme consequences on the overall value of seagrass, unless the meadow is critical or part of a larger scale, cumulative loss. Regional or widespread scale: Loss of more than 20% of a critical meadow, or of multiple meadows, for more than 5 years. Even if the activity ceases, natural recovery is unlikely within 10 years.
Seagrass-value-assessment-guidelines.docx