Site-selection model for optimal transplantation of eelgrass Zostera marina in the northeastern US

Abstract

A site-selection model for eelgrass Zostera marina L. ecosystem restoration was developed in the northeastern US to select optimal areas for transplanting eelgrass. The site-selection model synthesizes available historic and literature-based information, reference data, and simple field measurements to identify and prioritize locations for large-scale eelgrass transplantation. Model development was based on the physical and biological characteristics associated with the most successful transplant sites in a mitigation project for the New Hampshire Port Authority. The site-selection process is divided into 3 phases: (1) the first phase uses available environmental information to formulate a preliminary transplant suitability index (PTSI) for pre-screening and eliminating unsuitable sites; (2) the second phase involves field measurements of light availability and bioturbation as well as survival and growth of test transplants at priority sites identified by the PTSI; (3) a transplant suitability index (TSI) score is calculated for each site based on the PTSI and the results of field assessments. The TSI is a multiplicative index that eliminates sites which receive ratings of zero and gives high scores to those sites with the greatest potential for successful transplantation. We applied the TSI post hoc to the New Hampshire Port Project's eelgrass transplant sites, and subsequently the site-selection model was used in an eelgrass restoration project in New Bedford Harbor, Massachusetts. After 2 yr of transplanting, the New Bedford Harbor effort has resulted in success at 62% of the sites planted using the site-selection model.