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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Mar. Sci. | doi: 10.3389/fmars.2019.00052

Open coast seagrass restoration. Can we do it?

  • 1Centro de Ciências do Mar (CCMAR), Portugal
  • 2Joint Nature Conservation Committee, United Kingdom
  • 3Instituto Superior de Psicologia Aplicada (ISPA), Portugal
  • 4CSA Ocean Sciences Inc., United States

Abstract
Some of the major challenges in seagrass restoration on exposed open coasts are the choice of transplant design that is optimal for coastlines periodically exposed to high water motion, and understanding the survival and dynamics of the transplanted areas on a long time-scale over many years. To contribute to a better understanding of these challenges, we describe here part of a large-scale seagrass restoration program conducted in a Marine Park in Portugal. The goal of this study was to infer if it was possible to recover seagrass habitat in this region, in order to restore its ecosystem functions. To infer which methods would produce better long term persistence to recover seagrass habitat, three factors were assessed: donor seagrass species, transplant season, source location. Monitoring was done three times a year for 8 years, in which areas and densities of the planted units were measured, to assess survival and growth. The best results were obtained with the species Zostera marina transplanted during spring and summer as compared to Zostera noltii and Cymodocea nodosa. Long-term persistence of established (well rooted) transplants was mainly affected by extreme winter storms but there was evidence of fish grazing effects also. Our results indicate that persistence assessments should be done in the long term, as all transplants were successful (survived and grew initially) in the short term, but were not resistant in the long term after a winter with exceptionally strong storms. The interesting observation that only the largest (11 m2) transplanted plot of Z. marina persisted over a long time, increasing to 103 m2 in 8 years, overcoming storms and grazing, raised the hypothesis that for a successful shift to a vegetated state it might be necessary to overpass a minimum critical size or tipping point. This hypothesis was therefore tested with replicates from two donor populations and results showed effects of size and donor population, as only the larger planting units from one donor population persisted and expanded. It is recommended that in future habitat restoration efforts large planting units are considered.

Keywords: Stable states, bi-stability, Marine population transplanting, Long term habitat monitoring, Resilient minimum critical size

Received: 18 Aug 2018; Accepted: 30 Jan 2019.

Edited by:

Stelios Katsanevakis, University of the Aegean, Greece

Reviewed by:

Bernardo Duarte, Center for Marine and Environmental Sciences (MARE), Portugal
Oscar Serrano, Edith Cowan University, Australia
Marieke M. Van Katwijk, Radboud University Nijmegen, Netherlands  

Copyright: © 2019 Paulo, Cunha, Boavida, Serrao, Gonçalves and Fonseca. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Mr. Diogo F. Paulo, Centro de Ciências do Mar (CCMAR), Faro, Portugal, dfpaulo@ualg.pt
Dr. Emanuel J. Gonçalves, Instituto Superior de Psicologia Aplicada (ISPA), Lisbon, 1149-041, Lisboa, Portugal, emanuel@ispa.pt