Evaluating the ability of bivalve facilitation to enhance seagrass bed resilience to disturbance

Authors:
Sarah Donaher

Publication Date:
2019

Abstract/Summary:
Human-induced degradation of seagrasses has accelerated across the globe. Restoring these productive habitats has proven to be both challenging and costly, particularly once a bed has been entirely lost.  Therefore, it is critical to develop and test alternative approaches that promote existing bed resilience to disturbance. One such approach is the incorporation of positive species interactions into restoration design. We hypothesize that facilitation from a mutualist bivalve (the hard-shell clam) could aid in seagrass bed restoration by assisting in a rapid return to favorable environmental conditions for seagrasses after a disturbance. We tested the ability of bivalve facilitation to increase mixed community seagrass bed resilience in North Carolina, USA to two separate disturbance regimes: physical perturbation from propeller scars and excess water column nutrients. We monitored the effect of clam addition and disturbance on seagrass bed characteristics including growth rate, shoot density, epiphyte load, and more. There was no statistically significant effect among treatments for the first summer of the experiment, however we hypothesize for subsequent growing seasons that clam presence will enhance seagrass recolonization into propeller scars and reduce epiphytic loads under nutrient-loading scenarios. These findings would suggest that harnessing ecological facilitation can be an effective restoration technique for degraded seagrass beds. Understanding how mutualistic plant-animal interactions may reduce seagrass recovery time will allow managers to modify restoration designs to take advantage of natural ecological relationships across a variety of geographic locations and environmental conditions.

Resource Type:
Audio/Video, Conference Presentation, SER2019

Pre-approved for CECs under SER's CERP program

Source:
Society for Ecological Restoration