ABSTRACT
Eelgrass beds constitute key habitats in shallow, coastal areas that support high species diversity and provide mankind with several important ecosystem services. Eelgrass habitats have been identified as essential habitats in need of protection by international conventions and EU-directives. Along the Swedish northwest coast, more than 60%, approximately 12,500 ha, of the eelgrass beds have vanished since the 1980’s as a result of coastal eutrophication and overfishing. Although measures have reduced nutrient pollution and overfishing, and the water quality along the Swedish west coast has improved, no general recovery of eelgrass has been observed. Instead, the loss of eelgrass continues, partly due to an increasing exploitation of Swedish coasts.
The aim of this report is to contribute to the development of an improved management of eelgrass ecosystems in Sweden, in particular regarding the use of eelgrass restoration, but also in relation to licensing and supervision of activities that can affect eelgrass and other coastal habitats. The goal has been to assemble all relevant information in one report, and provide a multidisciplinary background that address ecological, legal and economic aspects of management and restoration of eelgrass in Sweden. Another objective has been to analyze the existing management of eelgrass in Sweden, identify possible shortcomings, and provide recommendations on how it could be improved. The report constitutes an important basis for the handbook for eelgrass restoration in Sweden (Moksnes et al. 2016).
Although functional methods and guidelines for eelgrass restoration are now available for Swedish waters, it is important to point out that restoration of eelgrass is very labor intensive, expensive and not possible in all areas. When a large eelgrass bed is lost, the physical and biological environment may change so much that eelgrass can no longer grow in the area. It is therefore critical that environmental managers prioritize the protection and conservation of remaining eelgrass habitats, and restore lost meadows when possible, but only as a last resort use compensatory restoration of eelgrass as a measure to mitigate losses caused by coastal exploitation.
Eelgrass meadows create several important ecosystem functions, which in turn provide society with important ecosystem goods and services. A bioeconomic analysis of three of these services (production of commercial fish and uptake and storage of carbon and nitrogen), estimates their economic value up to approximately 0.5 million SEK per hectare of eelgrass along the Swedish northwest coast. It is important to note that this value did not include several other important ecosystem services (e.g. increasing biodiversity, stabilization of sediment and prevention of beach erosion). The historical losses of eelgrass along the Swedish northwest coast were estimated to have caused a total loss of approximately 8000 tons in cod catches, which is equivalent to the total catch of cod in Swedish waters in 2013. The historic loss of eelgrass was also estimated to have caused a release of 6000 tons of sequestered nitrogen to coastal waters, which is three times larger than the annual river supply to the Swedish northwest coast. A rough estimate of the total economic value of the lost ecosystem services since 1990, including carbon sequestration varies between 4 and 21 billion SEK.
There is no Swedish legislation that protects eelgrass meadows specifically, but a large number of laws and regulations that aim to prevent deterioration or restore deteriorated environments, or regulate what type of influence is allowed in different areas. However, the fact that exploitation of eelgrass is allowed also in areas where large historical losses have occurred, as well as within marine protected areas, demonstrates that the existing legal protection is insufficient. The situation is not in agreement with the EU water framework directive and the marine strategy framework directive to obtain and maintain good ecological and environmental status, and makes it difficult for Sweden to fulfill international commitments.
The present management of eelgrass in Sweden is impeded by a lack of environmental monitoring and use of eelgrass when assessing the environmental status according to the EU directives. It is therefore important to revise the present indicator for coastal vegetation in Sweden, and to include the distribution of eelgrass in the national monitoring program so that the condition of the eelgrass ecosystems contributes to the classification of the environmental status. Together with a no-net-loss policy, such a change would increase the protection of eelgrass substantially and also clarify the need to carry out large-scale restoration of lost eelgrass meadows.
Compensatory mitigation has been used very little in the marine environment in Sweden, and no compensatory restoration of eelgrass has yet been carried out. Compensatory restoration could constitute a tool to implement the “polluter pays principle”, and contribute to prevent net-losses off eelgrass habitats caused by coastal exploitation. In contrast to the present use of economic-fees to compensate the fishery when an eelgrass bed is damaged, all ecosystem services would be compensated for after a successful compensatory restoration. However, compensatory mitigation is not unproblematic and it is critical that the compensation does not affect the permission process, but that it is only used as a last resort after all possibilities to avoid and minimize the damage have been exhausted. This is particularly important in the southern part of the Swedish northwest coast where studies have shown that there are areas where restoration is not possible. Moreover, due to the large historic losses of eelgrass in this region, most areas where compensatory restoration could be attempted consist of bottoms where eelgrass was growing in the 1980’s. Restoration in those areas would only compensate for the historic losses, but not for the eelgrass harmed by exploitation, resulting in a net loss of habitat.
In Swedish legislation there are several alternative sections of law that could be used to demand compensatory mitigation when eelgrass is affected negatively by an activity. The best support for demanding full compensation is in the Swedish environmental code (miljöbalk) chapter 16, section 9. Until recently, the lack of established practice has constituted a challenge to demand compensatory mitigation in the marine environment. However, this is about to change as land- and environmental courts have started to demand of compensation. It is recommended to increase the use of “biotope-protected areas” for eelgrass habitats as this protection would increase the possibility to demand compensatory mitigation for eelgrass, and more importantly, put higher demand to avoid and minimize damage on eelgrass habitats.
Experience from the USA, where compensatory restoration of eelgrass has been used as a management tool since the 1970’s, has shown the value of developing state wide policies regarding what methods that should be used during restoration, how the extent of the restoration should be calculated, and how the success of the restoration should be determined. A national eelgrass mitigation policy would facilitate the use and the chances of success for compensatory restoration in Sweden, and this report presents a detailed description of how such a policy could be designed.
Download Appendix 1. Historical eelgrass losses along the Swedish west coast (pdf)
Download Appendix 2. Recommendations for eelgrass mitigation policies in Sweden (pdf)
