Optimizing the restoration of the threatened seagrass Posidonia australis: plant traits influence restoration success

Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost-effectiveness of restoration projects. We aim to optimize restoration of the threatened seagrass Posidonia australis by identifying the traits of donor material that best predict survival and establishment. To avoid collecting donor material from threatened populations, a recent restoration method focuses on using naturally detached fragments of P. australis collected from the shoreline, which are stored in outdoor tanks prior to planting. Here, we examine 10 morphological traits of P. australis fragments and other variables relating to collection method to identify which traits best predicted survival after replanting. Fragments with more shoots and less dead tissue (necrosis) in their leaves had higher survival 1 year after planting. Fragments that were stored longer in tanks prior to replanting had significantly higher survival rates. These results can refine the selection for donor material used in restoration and optimize the recently developed restoration technique for P. australis using beach-cast seagrass material.