een experts on ecology and economy, VALUES i) developed a general framework that provides quantitative assessments of the value associated with services stemming from specific habitats under different human pressure levels, and ii) showed how coherent mapping of ecosystem service values in relation to impacts of major human activities can be successfully integrated in a long term sustainable management of the Baltic Sea. Mapping and valuation of the coastal environment is an important part of environmental objectives assessment as well as Habitats- and Marine Strategy Framework Directives reporting. The project increased the understanding of possibilities and limitations of using the value of marine ecosystem services in a management context.
The first study covered shallow, vegetated coastal habitats in the Baltic Sea. The coastal zone provides essential habitats for a large part of the economically most important fish species such as pike, perch and pikeperch. Of particular importance are shallow vegetated bays and lagoons, as availability to these habitat types have been shown to determine the production and sizes of fish populations. Several important ecosystem services are associated with the shallow vegetated bays functioning as fish reproduction areas. The habitat type provides food and opportunities for recreational fishing, while predatory fish dependent on the habitat type is important for ecosystem functioning through controlling growth of nuisance algae and indirectly habitat and water quality. Thus, these shallow sheltered bays constitute a habitat type maintaining a number of valuable ecosystem services, while at the same time being subject to several human pressures, as the dense human populations along the coasts put high, and accelerating, pressure on the coastal ecosystem through overexploitation, habitat transformation and pollution, threatening the valuable ecosystem services provided by these shallow-water habitats. A recent analysis shows that these habitats constituting fish reproduction areas are subject to heavy exploitation through shoreline construction, and that habitat degradation rates due to construction are accelerating. Simultaneously the reproduction habitats are highly affected by eutrophication. The effects of eutrophication on the habitats and indirectly on fish stock sizes are multifaceted, with some species losing and others actually gaining from the effects of eutrophication. The picture is further complicated by the fact that fishing, as an additional type pressure, may indirectly lead to a decrease in the quality of fish reproduction habitats by relaxing the top-down control of filamentous nuisance algae maintained by predatory fish.
The second study concerned aphotic soft substrate sediments, which cover approximately 90% of the Baltic Sea seafloor and provide crucial ecosystem functions such as decomposition of organic matter and re-mineralization of nutrients. Despite this, the importance of aphotic soft sediments in an ecosystem service context has largely been neglected, where previous studies in the Baltic Sea have mainly focused on near-shore ecosystem services. The human introduction of Marenzelleria, a polychaete genus, into the Baltic Sea has most likely changed crucial benthic processes that provide ecosystem services on a Baltic Sea-wide scale. Currently, knowledge on the large scale consequences of the Marenzelleria introduction on the Baltic Sea soft sediment ecosystem is severely lacking. By combining the quantification of biogeochemical processes in the presence or absence of Marenzelleria with high resolution maps of the modelled distribution of the species group in the Baltic Sea, its impact on nutrient cycling and release of contaminants can be quantified on a Baltic Sea scale. There are clear needs from a management perspective for data on the potential costs/values of marine non-indigenous species. This is both needed as examples of potential costs related to lack of preventive actions (there are no viable management options for a Baltic Sea wide Marenzelleri