Guidelines for seagrass restoration: Importance of habitat selection and donor population, spreading of risks, and ecosystem engineering effects (original) (raw)
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Open Coast Seagrass Restoration. Can We Do It? Large Scale Seagrass Transplants
Frontiers in Marine Science, 2019
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 timescale 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 m 2) transplanted plot of Z. marina persisted over a long time, increasing to 103 m 2 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 (PUs) from one donor population persisted and expanded. It is recommended that in future habitat restoration efforts large PUs are considered.
Global analysis of seagrass restoration: the importance of large-scale planting
Journal of Applied Ecology, 2015
1. In coastal and estuarine systems, foundation species like seagrasses, mangroves, saltmarshes or corals provide important ecosystem services. Seagrasses are globally declining and their reintroduction has been shown to restore ecosystem functions. However, seagrass restoration is often challenging, given the dynamic and stressful environment that seagrasses often grow in. 2. From our worldwide meta-analysis of seagrass restoration trials (1786 trials), we describe general features and best practice for seagrass restoration. We confirm that removal of threats is important prior to replanting. Reduced water quality (mainly eutrophication), and construction activities led to poorer restoration success than, for instance, dredging, local direct impact and natural causes.
The Genetic Component of Seagrass Restoration: What We Know and the Way Forwards
Water
Seagrasses are marine flowering plants providing key ecological services and functions in coasts and estuaries across the globe. Increased environmental changes fueled by human activities are affecting their existence, compromising natural habitats and ecosystems’ biodiversity and functioning. In this context, restoration of disturbed seagrass environments has become a worldwide priority to reverse ecosystem degradation and to recover ecosystem functionality and associated services. Despite the proven importance of genetic research to perform successful restoration projects, this aspect has often been overlooked in seagrass restoration. Here, we aimed to provide a comprehensive perspective of genetic aspects related to seagrass restoration. To this end, we first reviewed the importance of studying the genetic diversity and population structure of target seagrass populations; then, we discussed the pros and cons of different approaches used to restore and/or reinforce degraded popula...
Testing alternate ecological approaches to seagrass rehabilitation: links to life‐history traits
Journal of Applied …, 2010
1. Natural resources and ecosystem services provided by the world's major biomes are increasingly threatened by anthropogenic impacts. Rehabilitation is a common approach to recreating and maintaining habitats, but limitations to the success of traditional techniques necessitate new approaches. 2. Almost one-third of the world's productive seagrass meadows have been lost in the past 130 years. Using a combined total of three seagrass species at seven sites over 8 years, we experimentally assessed the performance of multiple rehabilitation methods that utilize fundamentally different ecological approaches. 3. First, traditional methods of transplantation were tested and produced varied survival (0-80%) that was site dependent. Secondly, seedling culture and outplanting produced poor survival (2-9%) but reasonable growth. Finally, a novel method that used sand-filled bags of hessian to overcome limitations of traditional techniques by facilitating recruitment and establishment of seedlings in situ produced recruit densities of 150-350 seedlings m )2 , with long-term survival (up to 38 months) ranging from 0 to 72 individuals m )2 . 4. Results indicate that facilitating seagrass recruitment in situ using hessian bags can provide a new tool to alleviate current limitations to successful rehabilitation (e.g. mobile sediments, investment of time and resources), leading to more successful management and mitigation of contemporary losses. Hessian bags have distinct environmental and economic advantages over other methods tested in that they do not damage existing meadows, are biodegradable, quick to deploy, and cost less per hectare (US$16 737) than the estimated ecosystem value of seagrass meadows (US$27 039 year )1 ). 5. Synthesis and applications. This research demonstrates how exploring alternate ecological approaches to habitat rehabilitation can expand our collective toolbox for successfully re-creating complex and productive ecosystems, and alleviate the destructive side-effects and low success rates of more traditional techniques. Moreover, new methods can offer economic and environmental solutions to the restrictions placed upon managers of natural resources.
Limited effects of source population identity and number on seagrass transplant performance
PeerJ, 2017
Global declines in coastal foundation species highlight the importance of effective restoration. In this study, we examined the effects of source population identity and diversity (one vs. three sources per plot) on seagrass (Zostera marina) transplant success. The field experiment was replicated at two locations in Massachusetts with adjacent natural Zostera marina beds to test for local adaptation and source diversity effects on shoot density. We also collected morphological and genetic data to characterize variation within and among source populations, and evaluate whether they were related to performance. Transplants grew and expanded until six months post-transplantation, but then steadily declined at both sites. Prior to declines, we observed variation in performance among source populations at one site that was related to morphological traits: the populations with the longest leaves had the highest shoot densities, whereas the population with the shortest leaves performed the...
Going with the flow: Facilitating seagrass rehabilitation
Ecological Management & Restoration, 2004
Techniques used to-date have focused on vegetative transplants that, while reasonably successful, may impact donor meadows. Can larger areas of seagrass be restored using seedlings and other non-destructive 'recruitment facilitation' methods? Stephanie Seddon is currently an Associate Lecturer with the School of Biological Sciences at the University of Sydney (Tel. +61-2 9036 9184, Email: sseddon@bio.usyd.edu.au). This feature is based on an ongoing program initiated by Stephanie while working with the Aquatic Sciences division of the South Australian Research and Development Institute (SARDI), to investigate the potential for seagrass restoration in Adelaide metropolitan waters.
Seagrass Conservation Biology: An Interdisciplinary Science for Protection of the Seagrass Biome
In the past three decades seagrass research has adopted several disciplines and matured into a global science. One of the approaches we can use to focus our science to benefit the management and protection of seagrass is that of Conservation Biology; a proactive field of science bringing together academic, government, and nongovernmental organizations from a wide range of disciplines to understand and conserve biodiversity. This relatively recent field synthesises and directs insights from many disciplines for direct application to the protection and conservation of species, communities, and biomes (Fig. 1). While the primary focus for conservation biology comes from ecology, genetics, landscape ecology, population biology and taxonomy, the discipline also incorporates analytical procedures associated with the social sciences, biogeography, and evolutionary biology (Soule and Wilcox, 1980; Soule, 1985; Meffe and Carroll, 1994; Primack, 2000). Conservation biology recognizes that humans derive both extractive and intrinsic benefit from the natural world and embraces methods and analyses utilized in fisheries science, agriculture, anthropology, economics, law, philosophy, and sociology. Today, unlike traditional approaches that were rooted in the preservation and management of selected species, conservation biologists are advising natural resource managers to focus more on an ecosystem approach that includes entire biomes, and to recognize that public trust demands comprehensive protection of biodiversity as much as sustaining the yield of harvestable organisms. Conservation biology endeavors to maintain and protect biodiversity at all spatial scales, including a variety of little understood and often overlooked life forms. In the broader meaning of biodiversity we are interested in conserving ecological services as much as life forms (sensu Randall, 1986).
Restoration Ecology, 2008
Restoration has become an integral part of coastal management as a result of seagrass habitat loss. We studied restoration of the seagrass (Halodule wrightii) near Tampa Bay, Florida. Experimental plots were established in June 2002 using four planting methods: three manually planted and one mechanically transplanted by boat. Seagrass cover was recorded at high resolution (meter scale) annually through July 2005. Natural seagrass beds were concurrently examined as reference sites. We also evaluated the suitability of a commonly used protocol (Braun-Blanquet scores, BB) for comparing the development of seagrass cover using the planting methods and quantifying spatial patterns of cover over time. Results show that BB scores mirrored conventional measures of seagrass characteristics (i.e., shoot counts and above- and belowground biomass) well when BB scores were either low or very high. However, more caution may be required at intermediate cover scores as judged by comparison of BB scores with direct measurement of seagrass abundance. Significant differences in seagrass cover were detected among planting methods and over time (2002–2005), with manual planting of rubber band units resulting in the highest cover. In contrast, the peat pot and mechanical planting methods developed very low cover. Recovery rates calculated from development of seagrass spatial cover were less than those reported for natural expansion. Importantly, time to baseline recovery may be substantially greater than 3 years and beyond standard monitoring timelines. Prolonged recovery suggests that the rate of service returns, critical for estimating compensatory restoration goals under habitat equivalency analysis, may be severely underestimated.
Restoration of seagrass habitat leads to rapid recovery of coastal ecosystem services
Science Advances, 2020
There have been increasing attempts to reverse habitat degradation through active restoration, but few largescale successes are reported to guide these efforts. Here, we report outcomes from a unique and very successful seagrass restoration project: Since 1999, over 70 million seeds of a marine angiosperm, eelgrass (Zostera marina), have been broadcast into mid-western Atlantic coastal lagoons, leading to recovery of 3612 ha of seagrass. Well-developed meadows now foster productive and diverse animal communities, sequester substantial stocks of carbon and nitrogen, and have prompted a parallel restoration for bay scallops (Argopecten irradians). Restored ecosystem services are approaching historic levels, but we also note that managers value services differently today than they did nine decades ago, emphasizing regulating in addition to provisioning services. Thus, this study serves as a blueprint for restoring and maintaining healthy ecosystems to safeguard multiple benefits, including co-benefits that may emerge as management priorities over time.
Changing Paradigms in Seagrass Restoration
Restoration Ecology, 2012
Sharing experiences and results among scientists and managers working on seagrass restoration was the main objective of the first European Seagrass Restoration Workshop that gathered researchers from around Europe. The meeting was the first forum in Europe that allowed for scientists, NGOs, and managers to interact and share their experiences relating to seagrass restoration and management. The results show that none of the seagrass restoration programs developed in Europe by the participants during the last 10 years was successful. Furthermore, an informal review of data published in seagrass restoration success, showed that the results reported were biased because they were mostly based on a very short monitoring period (i.e. <1 year). Numerous decision trees, guidelines, and restoration models have been developed to aid seagrass restoration management, but the results of this workshop point toward a new paradigm in seagrass restoration were efforts should shift to give priority to natural restoration potential, with an emphasis on the fact that restoration should never be considered the first alternative when planning for the mitigation of coastal development projects or to justify mitigation as a compensation measure for economic activities.