Seagrass-Watch : Manual for Maping & Monitoring Seagrass Resources

Managing Seagrasses for Resilience to Climate Change

Study Identifies Bottlenecks in Early Seagrass Growth

Seagrass

THE PROCESSStep 1 | Scope context, needs, and optionsTo start, map the various locations of seagrass. Together with local communities,&nbsp;analyze whether and how the health of seagrass meadows has changed in the recent past. If seagrass meadows are considered stable, you may not need to invest in assisted natural recovery. However, consider options to preserve existing seagrass - such as regulating and reducing pollution and direct human activities within and close to seagrass areas.&nbsp;Survey and select sites to explore whether prevailing environmental conditions favor seagrass restoration. Develop baseline maps to allow for monitoring of changes in distribution and abundance.Improve management to reduce human impacts and to maintain seagrasses in as healthy a condition as possible. This will enable the plants to better cope with and recover from stresses, including climate change. There is no substitute for effective management and good water quality to enhance seagrass resilience.&nbsp;Identify and protect seagrass areas that are healthy and strong and at low risk to human and natural event threats. These will serve as future seeding/transplanting recovery areas. Aim to do this across a wide geographic and seagrass species range.&nbsp;Identify interdependencies with other habitats like mangroves and reefs and seek to improve marine protected area networks. If seagrass meadows have been degraded, work with coastal communities as described in step 1 of appendix A.1 (reefs).&nbsp;Step 2 | Find further factsFollowing the initial scoping, conduct a review of the enabling environment. Now, let's explore the following aspects:<ul><li>Stakeholders. who might be affected and who might affect the project? List all the potential stakeholders and list possible roles they may play (positive and/or negative). Use multiple sources and review the list regularly.</li><li>Who might be your allies? These can include donors, community and industry volunteers, technical and logistical support entities, as well as seagrass and climate science experts. Select the experts who can provide technical advice.</li><li>Identify local regulations. What regulations exist, and which authorities are responsible for enforcing them? Ensure you look at local disaster risk reduction policies and regulations. Make sure these authorities are included in the stakeholder list.&nbsp;</li><li>Site-specific contexts. Are there other ecosystems and environmental issues that need to be addressed to ensure success?&nbsp;</li></ul>Step 3 | Assess seagrass vulnerability and resilienceIf the overall enabling environment is deemed strong enough, conduct a technical assessment of the seagrass status (in terms of current status, vulnerability, and resilience).&nbsp;Complete a resilience and vulnerability assessment to ensure potential impacts on seagrass meadows are considered. Resilience assessments should include exploration of the ecological resilience - the health and function of the ecosystems habitats, organisms, and ecosystem processes including reproductive cycles, population connectivity and recruitment (connection to healthy populations), species, soils, and water quality. Consider using the <a href="http://reefresilience.org/community-based-climate-adaptation/climate-adaptation-tools/ccap-adaptation-design-tool/" target="_blank">Adaptation Design Tool</a> to explicitly consider climate change in your design. &nbsp;Step 4 | Set targets and objectivesNow, set your objectives for restoration. Ideally, aim for a model that returns the seagrass to its original (non-degraded) status.&nbsp;Align these objectives with your overall project objectives and the timeframe. Use SMART indicators to define how you will measure progress and revise your objectives as needed.&nbsp;Identify initial monitoring measures - these may be refined later. See the ‘favorable conditions' section below to develop seagrass-specific indicators.Step 5 | Identify restoration optionsAt this stage, you have defined what you want to achieve. Now,&nbsp;let’s have a look at how to achieve your objectives.&nbsp;Where to focus on: Once your vulnerability and resilience&nbsp;assessment has been completed, select sites for restoration on the basis of the information you have collected. List the sites or areas with the best combination of low vulnerability to climate change and human impacts and the highest resilience. Consider how a restored seagrass will support disaster risk reduction.What actions to choose from: review potential adaptation actions. Ensure you have specific technical and scientific advice when deciding on actions. Use common evaluation criteria to decide what actions to take - including effectiveness, feasibility, urgency, flexibility, and externalities. Ensure that all key stakeholders are engaged in the process.&nbsp;Restoration of seagrass occurs through improved environmental conditions - for instance through improved water quality. This can encourage natural regeneration. It may involve seeding or transplanting of seedlings or mature plants from a variety of widely-distributed seagrass donor beds (thereby preserving genetic diversity).&nbsp;In some cases, combinations of all methods can be used to aid recovery. Restoration objectives, local conditions, seagrass species and project budgets will determine which planting approach is most appropriate for a given site.&nbsp;Restoration planning guidelines include identifying project goals regarding seagrass coverage, species composition, and ecological function of restored seagrass beds. If no restoration appears feasible, consider whether other actions could be conducted (see figure A4.1).Step 6 | Implement actionsExpert advice is required when planning and implementing seagrass restoration. See material for planning and monitoring seagrass restoration <a href="https://www.seagrasswatch.org/manuals/" target="_blank" style="color: rgb(102, 163, 224);">here</a>.&nbsp;A. Natural recolonizationNatural recolonization involves the process of improving the environment of the seagrass - usually through a combination of improving water quality and optimizing light access to promote photosynthesis.&nbsp;Water quality is most often affected by drain discharge, stormwater run-off, and effluent disposal. Dredging, shipping, and boat activity, as well as&nbsp;trawling of the sea bed also acts to reduce the water quality around seagrass areas.&nbsp;Management of these impacts must be addressed prior to any attempts at recolonization. Transplantation of healthy rhizomes and/seeding (using species found in the area) can then be used to support natural recolonization.B. Transplanting seedlingsSeedlings, either collected from nearby donor sites or raised in nurseries, can be transplanted directly into areas for restoration. This is a labour-intense method - however, it can have a faster results in terms of re-establishing seagrass meadows.&nbsp;Rhizomes or seedlings are fixed in grid systems to the ocean floor using a number of different methods. These include small metal u-shaped stakes to hold seedlings in place, laying sandbag snakes across the tide movement and then planting seedlings behind them. Frames are locked into place on the seabed to provide a base on which seagrass can be planted.&nbsp;Special (hessian) bags are placed on the seafloor to hold seagrass seedlings in place. By the time the hessian bags decompose, many seedlings are sufficiently established.&nbsp;Watch the selection of videos with examples of these methods, below.&nbsp;C. Seeding&nbsp;Seeding, while a cheaper and slightly less labor-intensive method, requires access to healthy fruiting seagrass.&nbsp;Seeding densities appear to be critical to success, and recurrent seeding on an annual basis is required to create sufficient cover and build <a href="https://www.vims.edu/newsandevents/topstories/2017/seagrass_bottlenecks.php" target="_blank">seagrass density</a>. Partnerships between recreational and commercial fisherfolk, landcare, indigenous organizations, and government agencies are engaged in large-scale seeding programs in Australia.&nbsp;Fishermen were provided with collected seeds that they carefully placed into sand-filled hessian bags. They then took them&nbsp;out to sea in fishing boats to be ‘sown’ at low tide.

Process

High water qualitySufficient light is a key factor for healthy seagrass meadows. Water must not be too cloudy from suspended matter or plankton. Excessive algae growth (due to of high levels of&nbsp;minerals and nutrients, e.g. due to fertilizer runoff) may absorb too much light. At least 10% of the light at water surface should reach the seagrass leaves. Proximity to developed areas and rivers may threaten seagrass unless sediment, nutrient and wastewater runoff is contained.&nbsp;Mellow water movement&nbsp;Some water movement is important for the supply of nutrients and inorganic carbon to enable photosynthesis. Yet, the currents must not be too strong so as to uproot plants or stir up sediment.Good sediment conditionsThe root environment should be undisturbed, and the organic content of the sediment should be under 5%. Human activities such as dredging, heavy boating and fishing (especially bottom trawling) should be prevented.&nbsp;Genetic variability and connectivityGenetic variability between plants is important for seagrass resilience to temperature stress. Meadows with high genetic diversity should be prioritized for protection.Effective management&nbsp;Potential threats to seagrass meadows from human activities&nbsp;need to be managed&nbsp;(e.g. by limiting or preventing pollutant run-off) to sustain seagrass.&nbsp;

Favorable conditions for the survival of seagrass

Seagrass grows in shallow, sheltered, and soft-bottomed coastal waters and estuaries. More than 60 species of seagrasses exist worldwide and play important roles in shallow marine ecosystems (<a href="https://reefresilience.org/pdf/Managing_Seagrass_for_Resilience_to_CC.pdf" target="_blank" style="color: rgb(13, 102, 132);">Björk et al. 2018:16</a>).&nbsp;Their main protective benefits are wave attenuation and sediment trapping, thus reducing the risk of soil and coastal erosion, particularly after heavy rainfall. Seagrass meadows are nurseries for young fish, who feed in the nutrient-rich waters while hiding from predators.In terms of environmental benefits, seagrass is a powerful carbon sink and important habitat (home to 40 times more species than bare sand). Seagrass is also a food source (seeds) and used as material for roofing, mattresses and traditional medicine (ibid:17).Seagrass restoration and rehabilitation require scientific and technical advice. Specific actions may include efforts to improve water quality and light exposure, planting of seedlings or seeding areas for restoration, eliminating the causes of seagrass decline, raising awareness of the value of seagrass and inclusion in coastal management plans (ibid, 26-34)<img src="https://s3.us-west-2.amazonaws.com/static.natureprotects.org/Figure%205_Seagrass.png">﻿UNDERSTANDING SEAGRASSSeagrass meadows are rated the third-most valuable ecosystem on a per-hectare basis, only preceded by estuaries and wetlands. They have undergone a worldwide decline, primarily as a result of local pollution along coastlines.&nbsp;The plants grow best in clear and gently moving water. They require light and nutrients for growth. Run-off of wastewater and sediments reduces the light, often as a side-effect of excessive algae growth (which steal the light).&nbsp;Protecting seagrass meadows by restricting run-offs, pollution and direct physical disturbances by human activity is therefore the starting point, and usually the single most cost-effective measure.&nbsp;If there is - or has been - seagrass in your area, follow the guidance below, in the section titled "The Process".&nbsp;