VI.7 Marine Ecosystem Services
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VI.7 Marine Ecosystem Services Marissa L. Baskett and Benjamin S. Halpern OUTLINE 1. What and where are marine ecosystem services? 2. Theory and management of ecosystem services: Example of marine provisioning services 3. Current and future trends Marine ecosystems provide a variety of services: provisioning services such as fisheries, regulating services such as storm protection in coastal regions, supporting services such as primary production that can cross the land–sea boundary, and cultural services such as tourism. Understanding marine ecosystem services requires consideration of the appropriate spatial, temporal, and organizational scales for each service, and both empirical and theoretical investigations provide insight into these services and the relevant management practices. For example, theoretical population ecology has historically informed fisheries management, and disciplines such as community and spatial ecology can inform recent efforts to implement an ecosystem-based approach to managing the use of multiple marine ecosystem services. The impacts from a combination of human activities, from fishing to pollution, have led to declines in many marine ecosystem services. Future research on both the ecological and the socioeconomic aspects of marine ecosystems can guide sustainable management of the use of these services. GLOSSARY adaptive management. Dynamic resource management that incorporates new information gathered from scientific monitoring to systematically improve management practices ecologically sustainable fishery. Fishery regulated to avoid any shift in the ecosystem that leads to an undesirable state, such as collapsed populations of a harvested species ecosystem-based management (EBM). A holistic approach to resource management aimed at the sustainable delivery of multiple ecosystem services by accounting for the ecological, environmental, and socioeconomic context and explicitly addressing cumulative impacts and trade-offs among the different sectors being managed maximum sustainable yield (MSY). The largest yield that a fishery can theoretically sustain indefinitely stock–recruitment relationship. A mathematical description of the number of new recruits to a fishery as a function of the spawning stock size 1. WHAT AND WHERE ARE MARINE ECOSYSTEM SERVICES? There is an old adage that the oceans are inexhaustible in theirabilitytoprovideforhumansandabsorbourwastes— a proverbial, and simultaneous, supermarket and waste bin. Currently, there is little doubt that both of these beliefs are wrong, but the adage captures a reality about the world’s oceans: they provide a vast amount of ecosystem services to humanity. An increasingly large portion of our food comes from the oceans. Globally, about 5% of the protein in people’s diet comes from seafood , but this portion is dramatically higher in places such as China, Japan, and Iceland. An estimated 15% of the world’s species diversity is in the oceans, and 16 of the world’s 35 animal Phyla are found only in the oceans, whereas only one is found exclusively on land. The many services this biodiversity provides include providing biochemical and medical substances for human uses, higher and more stable fisheries catch, and spiritual (aesthetic) and cultural resources. The oceans also act as a massive carbon sink by converting CO2 into carbonic acid, which in turn slows global climate change (but increases ocean acidification). Specific ecosystems withinthe oceans, suchascoral reefs, mangroves, andsalt marshes, play important roles in buffering coastal areas from wave and storm damage. The 2004 Asian tsunami and 2005 Gulf of Mexico hurricanes dramatically illustrated the value of this service in protecting both human lives and property. In addition to these examples of provisioning and regulating services, the oceans provide critical supporting and cultural services. Salt marshes and shellfish reefs help filter and clean the polluted waters that run off the land; in temperate coastlines, upwelling zones, where nutrient-rich water is pushed from the deep into surface waters, act as major primary productivity pumps that fuel provisioning and regulating services. Such supporting services can even extend to terrestrial ecosystems. For example, salmon mortality after spawning migrations leads to substantial deposition of originally marine nutrients into riparian ecosystems , and seabird nesting sites provide a major source of nitrogen to coastal landscapes through the guano from these fish consumers. Finally, coastal areas are a major source of recreational and aesthetic value to many people. A day spent at the beach, bird-watching in coastal salt marshes, whale-watching tours, and scuba diving in coral reefs are all services that have great intrinsic value and support tourism industries. Patterns and Scale of Marine Ecosystem Services Understanding the capacity of the oceans to provide ecosystem services requires an appreciation of the temporal and spatial patterns in marine ecosystems and the human uses of those ecosystems. In...