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2 Conceptual Issues This chapter provides a summary of presentations outlining the conceptual issues of coastal waters and ocean ecosystem services and human health. The first presentation gives an overview of the concept of ecosystem services and ways to use this in natural resource management decision making and other practices of corporations and governments. The second presentation describes broad efforts to protect ecosystem services, using the Puget Sound and Gulf of Mexico as examples, and the need to develop indicators to assess the health of coastal and ocean environments and the services they provide to humans. The presentations are followed by a summary of the discussion that ensued. UNDERSTANDING ECOSYSTEM SERVICES Lydia Olander, Ph.D. Director, Ecosystem Services Program, Nicholas Institute, Duke University Lydia Olander began the presentation by defining the concept of ecosystem services as the benefits people obtain from ecosystems.1 The term ecosystem services is not an entirely new concept, she said. The notion of ecosystem services was included in the thinking of Gifford Pinchot, the first chief of the Forest Service, in the 1900s when he discussed conservation as the wise use of the earth and its resources for the lasting good of men. In contrast to the past, todayâs concept of 1 âAn ecosystem is a dynamic complex of plant, animal, and microorganism communities and the nonliving environment interacting as a functional unit.â Humans are an integral part of ecosystems (MEA, 2005). 5
6 ECOSYSTEM SERVICES AND HUMAN HEALTH ecosystem services goes beyond the typical services of timber production, grazing lands, crop production, and fish production to include the categor- ization, quantification, and valuation of a broader range of services. Additionally, she noted, the field is grappling with how to operationalize the concept for use in resource management decision making, and how to incorporate it into standard practices. The concept is moving beyond the realm of ecosystem scientists and economists to the decisions and actions of conservation organizations, governments, and corporations. According to Olander, one of the key events that changed thinking in the scientific community in the early 1990s was Biosphere 2, a research effort to recreate the biosphere and have a self-sustaining environment. Biosphere 2âs initial experiments failed to sustain human life in a closed and independent biosphere system as hoped. The biosphere experienced a broad range of negative impacts: oxygen levels plummeted, carbon dioxide levels skyrocketed, nitrous oxide rose to levels that impair brain function, and water purification failed. Further, of 25 vertebrate species studied, 19 died. Pollinators became extinct, and ants, cockroaches, and katydids became rampant. These results highlighted the fact that ecosystem services, the underpinning of human well-being, are not well understood and are difficult to recreate. Millennium Ecosystem Assessment and Ecosystem Changes Olander proceeded to describe the Millennium Ecosystem Assessment (MEA) (2005), an extensive effort to provide an integrated assessment of the consequences of ecosystem change for human well-being. The MEA identifies four categories of ecosystem services that lead to health and well-being: (1) provisioning, (2) regulating, (3) cultural, and (4) supporting services. Provisioning services are the typical goods produced or provided by ecosystems. These include foods such as crops, livestock, fish from capture fisheries and aquaculture, and wild foods. Fibers are another product category and typically include timber, cotton, hemp, silk, and wood fuel. In addition, genetic resources, freshwater provisions, biochemicals, natural medicines, and pharmaceuticals obtained from the environment are ecosystem provisions. These provisions tend to have a market value. Regulation and sustainability of ecosystem processes is another type of service and an important contributor to human health. These processes include climate regulation, air quality regulation, erosion regulation,
CONCEPTUAL ISSUES 7 water purification, disease and pest regulation, pollination, and natural hazard regulation such as flood protection. The category of cultural services is more abstract and includes non- material benefits obtained from ecosystems. Services such as spiritual and religious values, knowledge systems, education values, inspiration, aesthetic values, social relations, sense of place and recreation, ecotourism, and others are among those included in this category. Olander described an example of another cultural service that is not typically consideredâ darkness. In Puerto Rico, darkness is a very important part of the ecosystem and is critical to ecotourism and recreation. Bioluminescent bays, for example, draw many ecotourists but light pollution is a problem. The category of supporting services includes those services necessary for the production of all other ecosystem services such as primary production, production of oxygen or photosynthesis, and soil formation. Olander highlighted that biodiversity is underpinning all services. The MEA framework has been used in two ways, Olander said. The first way is in tracking the status of the environment as it relates to people or assessing trends in ecosystem services. The second way is in improving the management of natural resources. For example, the MEA framework was used to understand increased flooding across the globe. The MEA can help illustrate how flooding affects people; the impact can be seen in deaths, use of health care services, disease vectors, and many others. But it is useful in identifying and understanding the causes or drivers of flooding. Two reasons were identified as contributing to the human impact of flooding: (1) people increasingly occupy regions exposed to extreme events and (2) significant losses of coastal habitat reduces flood protection and increases the risk of floods. The latter describes the loss of ecosystem services. Loss of coastal habitat can be tracked as an indicator of increasing flood risk. In addition, by focusing on this driver, linkages to other services that might be lost or gained can be examined to understand trade-offs and synergies. The loss of coastal habitat can reduce shellfish and fish nurseries, which can result in fewer fish, fewer fish-related jobs, higher costs of fish, and fewer fresh fish available for consumption (the latter could have an impact on health). Further, the loss of coastal habitat can lead to a reduction in nitrogen transformation and storage which can increase the impact of nitrogen loading and increase the risk of eutrophication (high nutrient levels) leading to coastal dead zones and fish loss. But there can also be positive impacts such as better wave energy because sea grasses are not in the way
8 ECOSYSTEM SERVICES AND HUMAN HEAL M D LTH (e.g., to generate energy from surface wav m ves). Both th negative a he and positiv impacts mu be consider ve ust red. Th primary fin he nding of the MEA is that 60 percent (1 out of 24) of M 15 the ecoosystem services examined are being deg d graded or use unsustainab ed bly (MEA 2005). Eco A, osystem servvices that ha ave been deg graded inclu ude capture fisheries, water supply, waste treatme and detox w w ent xification, wat ter purific cation, natural hazard prote l ection, regulattion of air quaality, regulation of regiional and local climate, re egulation of eerosion, spirittual fulfillmen nt, and aeesthetic enjoym ment. The use of two ecosy e ystem services in particularâ s râ capture fisheries an freshwaterâ now we beyond lev that can be nd âare ell vels sustain at current demands, mu less futur levels, Olan ned t uch re nder said. An aspect of th MEA that needs to be hi n he n ighlighted, Olander noted, is, the eff to build linkages betw fort l ween the servvices and hum well-bein man ng. As can be seen in Figure 2-1, eco n F osystem servic are linked to constituen ces d nts of well-beingâsec curity, basic material for a good life health, good r e, social relations, an freedom of choice and actions. Th arrow colo nd o d he ors identif the potential for media fy ation by sociioeconomic f factors, and t the arrow widths iden ntify the intensity of linnkages betw ween ecosyste em service and human well-being. es n FIGUR 2-1 Linkag between eco RE ges osystem servic and human well-being. ces SOURC MEA, 2005. Reprinted wi permission f CE: ith from the Millen nnium Ecosyste em Assessm ment.
CONCEPTUAL ISSUES 9 Ecosystem Services Framework to Improve Natural Resource Management Decisions Olander continued with a discussion of the use of an ecosystems services framework to improve the management of natural resources. It is also important to understand how changes in resource management decisions affect the production of ecosystem services, she said. This relationship between management and actions and ecosystem services outcomes is called a production function by the scientific community. To further explain a production function, consider that X percent of habitat loss results in a Y percent decrease in coastal flood protection provided by the ecosystem, which results in a Z percent increase in an impact (for example, mortality). The question then is, how much reduction in coastal habitat, of which types and where, result in how much of an increase in flooding and of what type and where? Olander noted that there are trade-offs and synergies in the management of natural resources. A small change in coastal habitat may have a large impact on fisheries but only a small impact on flood protection. So it is important to understand the relationships across services. Further, if decisions need to be made, the trade-offs need to be evaluated. For example, people want to live in coastal zones for recreational, spiritual, and economic opportunities. But housing development and infrastructure can damage the services the coastal systems produce. Ideally ecosystem services approaches can make the trade-offs inherent in management choices (across services that matter to different people) explicit. Olander described a compelling example from the MEA related to mangroves. Natural mangroves provide many services, including nursery and adult fishery habitat, fuel wood and timber, and carbon sequestration; they detoxify pollutants and provide protection from erosion and natural disasters. However, the promotion of shrimp farming in these areas has raised concerns about the potential ecological and economic impact of clearing mangroves for shrimp farming. Researchers studying the value of mangrove conservation showed that while financial cost-benefit analysis demonstrates that it is financially worthwhile for an individual to convert mangrove forests into commercial shrimp farms, once other factors are taken into account, such as the water pollution from shrimp ponds and restoring the mangrove after the shrimp pond is abandoned, shrimp farming is no longer as economically beneficial to society (Sathirathai and Barbier, 2001). The study demonstrated that consideration of other values and changes in services may lead to different decisions.
10 ECOSYSTEM SERVICES AND HUMAN HEALTH Olander noted that there are a number of ways to approach valuation and comparing alternatives. Some are qualitative in nature, for example an ecosystem services management effects matrix (see Figure 2-2). The matrix allows decision makers to consider a range of management options and to assess their impact on ecosystem services against a gradient from strong positive to strong negative impact. Olander also described another framework commonly used by researchers, published by de Groot and colleagues (2010), which is useful for linking ecosystem services to human well-being in a way that facilitates quantification of impact. As shown in Figure 2-3, ecosystem services are generated by ecosystem functions. Ecosystem functions are intermediate between ecosystem processes and services and are generally described as the capacity of the ecosystem to provide goods and services that can benefit people. The actual use of the service provides benefits, and those benefits can be valued. Olander noted that value can be assessed based on stakeholder preferences or economic costs and benefits; however, economic value may be difficult to impossible to assess for some services. For example, market values are easier to assess for food services which are valued by the market than for cultural services such spiritual and religious benefits. A range of qualitative to quantitative ecosystem tools are available to value services. These tools continue to be evaluated and new tools are being developed. Below are some examples that show the range of different types of tools available: â¢ Ecosystem Services Review is a structured methodology for corporate managers to proactively develop strategies for managing risks and opportunities arising from their companyâs dependence and impact on ecosystems (Hanson et al., 2012). â¢ Integrated Valuation of Ecosystem Services and Tradeoff (InVEST)2 models are based on production functions that define how an ecosystemâs structure and function affect the flows and values of ecosystems (Tallis et al., 2010). â¢ Social Values for Ecosystem Services (SolVES)33is a geographic information system (GIS) application for assessing, mapping, and 2 InVEST is available at: http://www.naturalcapitalproject.org/download.html (accessed August 25, 2013). 3 SolVES is available at: http://solves.cr.usgs.gov (accessed August 25, 2013).
FIGURE 2-2 Ecosy F ytem services mana agement effects ma atrix applied to a m marsh scenario. 11 SOURCE: Personal communication, Pe Caligiuri, The Nature Conservancy September 11, 20 13. Reprinted with permission. S ete N y, 0 h
12 ECOSYSTEM SERVICES AND HUMAN HEAL M D LTH FIGUR 2-3 Framew RE work for linkin ecosystems a biodiversity to human we ng and y ell- being. NOTE: econ = econo omic, WTP = willingness to p w pay. SOURC Adapted from de Groot et al., 2010. R CE: f Reprinted with permission fro om Elsevieer. quantifying the social va g alues of ecosyystem service (Sherrouse et es al., 2011). â¢ Artificial Intelligence for Ecosyste Services (ARIES)47is a I f em Web-based technology to assist rapid ecos d y system serviice assessment and valuation (Bagstad et al., 2011). n t In summary, Olander high O hlighted that the concept of ecosyste t em cess which ca be used in quantitative or service is a logical thought proc es l an n qualita ative assessm ment of impli ications and trade-offs. E Efforts are no ow focuse on figuring out how to implement t ed g these methods more broad dly and to develop dec o cision-making tools, which continues to be a compl g h o lex challen nge. 4 ARIE is available at: http://www ES w.ariesonline.or (accessed Au rg ugust 25, 2013 3).
CONCE EPTUAL ISSUES 13 INTEGRATI ION OF ENV VIRONMENNTAL HEALLTH AND MAARINE ECO OSYSTEM S SERVICES Tracy Collier, Ph.D y D. Science Director, Puget Sound Partnership , d p Trracy Collier began by iden b ntifying the P Puget Sound P Partnership as a s good example of th integration of environm e he n mental health and ecosyste em service However, he added th a way to evaluate its e es. hat effectiveness is needed particularly to measure any increase in the servic produced b d, y ces by Puget Sound, as its protection an restoration have proved very costly. nd n d Coollier then ref gure from the World Healt Organization ferenced a fig e th (WHO (see Figur 2-4) which illustrates the intersect O) re h tion of climaate change and human health, poin e n nting out that though the m marine systemms and cooastal system were not explicitly cal ms lled out in th figure, th he hey would be encompa assed in the biodiversity l oss and ecos b system function and th decline in ecosystem se he ervices in gen neral. Collier explained th r hat although the work done to pr k rotect coastal ecosystems is focused on l provid ding services to the humans that use the all aspect of the coast t s em, ts tal ecosysstem should be considered. b FIGUR 2-4 Linkag between climate change a human heal RE ges and lth. SOURC WHO, 2013 Reprinted wit permission of the World Hea Organizatio CE: 3. th f alth on.
14 ECOSYSTEM SERVICES AND HUMAN HEALTH Much work is being done to identify the stressors that affect the coastal ecosystems, such as nutrients resulting from residential, agricultural, and urban runoff, and consequent harmful algal blooms, particularly cyanobacteria blooms. These stressors have greatly impacted delivery of ecosystem services such as drinking water and recreational access. Though there is a lot of information about stressors and how they affect our ecosystems, Collier noted that there was not very much known about how altered ecosystems actually affect humans. Puget Sound Partnership Christine Gregoire, governor of Washington state, created the new state agency, the Puget Sound Partnership, in 2007, to work toward a âswimmable, fishable, diggable Puget Sound by 2020.â Collier noted that this defined the political view of ecosystem services for the Partnership; however, in order to put together the policies and write the legislation to create a new state agency, more specific detail was needed. It also became clear that when identifying the types of ecosystem services to be achieved or protected, some kind of translation was necessary to help policy makers understand these terms. After much discussion, six primary goals were identified in order to restore and protect ecosystem services provided by Puget Sound: â¢ species and food webs (e.g., biological biomass and biodiversity), â¢ habitats and processes (e.g., eel grass as a habitat that contributes to shoreline protection),58 â¢ water quality issues (e.g., toxic contaminants, pathogens, and nutrients in the water), â¢ water quantity (the annual flows are highly variable, with serious consequences), â¢ human health, and â¢ human well-being. Collier said it was significant that this list explicitly calls out human health and human well-being as specific and separate goals for the Partnershipâs efforts to restore Puget Sound. However, it is important to find a way to measure improvements in the services and to establish their economic, social, and cultural values. 5 Eel grass softens the impact of waves and currents, preventing coastal erosion and providing a calm space where organic matter and sediments are deposited.
CONCEPTUAL ISSUES 15 Collier emphasized that salmon is an extremely important part of the Puget Sound ecosystem. There are five species of Pacific salmonâ chinook, chum, coho, pink, and sockeye. Along with steelhead and bull trout, many populations of all of these anadromous fish species (except pink salmon) are listed under the Endangered Species Act. In addition, there are very substantial legal requirements to maintain salmon populations as part of the tribal treaty rights, which Collier mentioned had been in the news recently, when regional tribes grew dissatisfied with what they perceived as a lack of progress in this area. Unfortunately, there is a great deal of habitat loss due to increasing urbanization, which impacts the salmon life cycle, threatening the juvenile salmon on their path downstream and in nearshore habitats. Puget Sound is unique among North American estuaries in that it was carved by glacial action and is a deep fjord with shallow sills. This reduces water circulation at several points so that it tends to be isolated hydrologically. Because it is so deep and marine, many species, including some salmon, spend their entire lives within the estuary, which is not the case in most estuaries, where animals come and go at different stages of their lives. It is isolated not only hydrologically, but also, to an extent, biologically. What goes into the Sound, such as toxics, tends not to flush out as happens in other estuaries. A study comparing polychlorinated biphenyls (PCBs) in whole-body chinook salmon along the West Coast found much higher levels in Puget Sound specimens than those to the north or south. These high levels of contaminants have led to fish consumption advisories, limiting Puget Sound salmon consumption. In fact, said Collier, this is a good example of an intersection between the ecosystem services and environmental health, affecting community issues important to policy makers. Deepwater Horizon Oil Spill and Seafood Safety Collier next spoke about the Deepwater Horizon explosion of spring and summer 2010. After acknowledging the tragic loss of human life, the fire, and the enormous release of oil into U.S. waters, he turned to the issue of seafood safety. About one-third of the federal fishing waters in the Gulf of Mexicoâa major portion of the U.S. fisheries supply, second only to Alaska and the Bering Seaâhad to be shut down for several months as a result of the disaster. It takes a long time after an oil spill has closed an area to determine when it can be reopened. Extensive chemical and sensory testing is required, and many hundreds of sites or fish must
16 ECOSYSTEM SERVICES AND HUMAN HEALTH be sampled to establish the safety of the seafood supply. The testing after the Deepwater Horizon oil spill was both lengthy and expensive. Aromatic hydrocarbons were presumed to be the most toxic components of oil spills, and fish sampled after the waters had been re- opened were expected to show low or no oil exposure, which federal sampling and analysis confirmed. Indeed, in some cases, levels of contamination were 100 to 1,000 times lower than the government-set levels at which human health is threatened (FDA, 2013). However, Collier noted that, despite these test results, it was very difficult to convince people of the safety of fish taken from the Gulf of Mexico. Another important aspect of the contamination levels set for safe human consumption of the fish, added Collier, is that fish start to die from the oil exposure at levels far below those set as safe for human consumption. This means that though the scientists knew that there was no chance the fish tested could have been contaminated to the point that eating them would have been a danger to human healthâbecause fish cannot live at that the level of contamination, dying at levels far below thatâstill, the analyses had to be done, to show people the fish were safe. Also, there is a point at which fish will start to smell of oil and, even though these fish would still be considered safe for consumption, they obviously should not be allowed into the market. Collier pointed out that this discrepancy creates a big disconnect between the work of scientists and actual risk to human safety. The point to consider here, Collier noted, is that most agree that marine fish consumption confers certain health benefits to humansâfor example, better cardiovascular health, better development of fetal brains, and perhaps even longer life. So, when a fishery is shut down for an oil spill or for levels of PCBs (as in the Puget Sound fish example above), a large part of what would be an otherwise beneficial food source is being removed from peopleâs diets. In other words, while shutting down fisheries or putting up fish consumption advisories is done to protect human health, there may well be adverse implications for human health as a consequence if the food source cannot be replaced, or is replaced with less healthy food. Collier mentioned that a study is being done on fish consumption in the Gulf of Mexico following the Deepwater Horizon explosion. He expressed a hope that sufficient good data would be collected to show if there was in fact a reduction in rates of fish consumption below normal consumption rates, and if there were a reduction, what connection could be made to any observable health outcomes.
CONCEPTUAL ISSUES 17 Public Perceptions About Seafood Safety Collier also discussed the difficulty in balancing public perceptions and communicating about seafood safety. The issue of public fear of fish contamination versus the health benefits of eating fish is a problem in Puget Sound, said Collier. Many people are very concerned about eating salmon (even though the PCB levels may not be health threatening), while on the other hand, there is a population of non-English speakers who need to be warned not to eat bottom fish from severely contaminated areas. Collier stressed that while the Puget Sound Partnership is cleaning up stormwater and reducing toxic and nutrient inputsâand thus improving the health of the biota, improving the safety of swimming beaches, and reducing harmful algal bloomsâthey should also be demonstrably improving human health by making access to safe seafood more reliable. Seafood should be regarded by the community as safe and beneficial for both recreational and commercial purposes. Climate Change Impact on Puget Sound Ecosystem Services Collier then moved to a consideration of climate change and its impact on ecosystem services as it relates to the loss and modification of salmon habitat. Millions of dollars are currently spent each year in an attempt to get salmon to return in greater numbers to the Sound. Climate change is important in that it affects river flows: projections for 2050 river flows show 30 to 50 percent less water in the streams in Puget Sound during the summer months, which is when many juvenile salmon are rearing in freshwater or making their downstream journey. These reduced water flows during the summer result from reduced snowpacks, in essence changing stream hydrology from snow-driven systems to rain-driven systems. Collier stressed that, in order to maintain ecosystem services in these regional recovery programs, planning for climate change is a necessity. Indicators to Assess the Health of Coastal and Ocean Environments The Global Ocean Health Index69is a comprehensive measure that scores ocean health. It provides an assessment of the health and benefits of the global ocean, looking at the types of ecosystem services that are 6 The Global Ocean Health Index is available at: http://www.oceanhealthindex.org (accessed September 9, 2013).
18 ECOSYSTEM SERVICES AND HUMAN HEALTH provided by the coastal oceans (such as food provision, recreation, and so forth). Collier noted that although assigning scores to the various areas is problematic, it is nevertheless a useful exercise, and the data gathered are important. In cooperation with some components of the Puget Sound Partnership, the scientists who created the index will be using their system to assess certain aspects of ecosystem services provided by Puget Sound. Collier pointed out that this system is driven not so much by the state of the ecosystemâas, for instance, biodiversityâbut rather is based on what services are provided to humans and is very focused on jobs and other human benefits. In terms of an ocean health index, Collier noted that the Aral Sea would receive an extremely low score (though, as a freshwater lake, it was not actually included in the index). It was once the fourth largest freshwater lake in the world, but with the diversion of water for farming it suffered a devastating loss of ecosystem services and subsequent great harm to human health and prosperity. Predictions of the oncoming environmental disaster were ignored by the Sovietsâthe Aral Sea is an example of what can go terribly wrong in ocean management. Nobody wishes anything similar to happen in the United States. In order to avert such disaster, a first step is to select good environmental indicators to measure the health of the environment. The Puget Sound Partnership has developed a dashboard of 21 vital signs which is used to report the health of Puget Sound and the effectiveness of its actions (see Figure 2-5). Collier noted that the indicators for the section called âHealthy Human Populationâ included on-site sewage systems and whether they were properly maintained, and whether swimming beaches and shellfish beds are open or closed (such closures are usually due to fecal contami- nation). He felt that these indicators were not the best ways of assessing human health. Also, the Puget Sound Partnership has not been successful in building robust indices that could measure quality of life or sound behavior (two of the indicators in the âHuman Quality of Lifeâ section) and has not been able to find good data for recreational fishing permits and commercial fishing harvests (the two other indicators in this section). Collier admitted that the Partnership could improve the human health and human well-being aspects of this dashboard system. However, he felt that they were progressing in developing indicators that link ecosystem services to a healthy economy. Work still needs to be done in valuing the cultural and the social aspects, but they are making good progress on economic indicators.
CONCE EPTUAL ISSUES 19 FIGUR 2-5 Puget Sound vital sig wheel. RE S gns SOURC Puget Soun Partnership, 2012. Vital si CE: nd igns wheel cen photo cred nter dit: Flickr/D Diana K. Co ollier conclud his presen ded ntation by str ressing that b better indicato ors to link coastal and marine cond k d dition to eco system servic and hum ces man health and well-be eing are need ded, and ask ked for any suggestions to further this goal. r DIS SCUSSION Ly Goldman began the di ynn n iscussion by p uestion, what do posing the qu we nee to know to quantify the impacts of ec ed o cosystem serv vices on healt th, especially economically? Olande responded that on the h er health side the ere are very good exammples of econnomic valuattion. She offe ered air quali ity protection through the Clean Air Act as on example where the link A ne
20 ECOSYSTEM SERVICES AND HUMAN HEALTH between ecosystem services protection and health has been assessed and the economic valuation quantified. She noted that it is more difficult to develop direct health outcomes and economic valuations for ecosystem services that are less concrete such as cultural, spiritual, and mental health but that efforts are being made in developing economic valuations for those services. Frank Loy commented that quantification is vital because it helps persuade individuals of the importance of the efforts made to protect ecosystem services. He cautioned, however, that quantification of services such as cultural, peaceful, and spiritual must be credible or one could undermine the ability to get public support for those efforts. Olander responded that there are risks with quantifying many things because of uncertainty in a number of parameters. She noted that there is a move away from valuation to evaluationâwhere stakeholder values are considered rather than economic valuation. Jack Spengler also addressed the issue of values and how solitude, reflection, and other aspects of how nature is experienced might be quantified. He emphasized that we should not shy away from developing outcomes that are measurable. He mentioned there is work ongoing in Japan and Finland to develop measures for the value of forests, including values that are more difficult to measure. Researchers in these countries have been looking at the restorative functions or therapeutic services provided by forests and at measures such as a reduction in cortisol levels or an increase in serotonin levels. He suggested that the field is a few years away from having the necessary outcomes, but progress is being made in this area. Christopher Portier commented that the ecosystem services impact on human health is much more difficult to measure, quantify, and value because health outcomes are often the result of a number of factors. For example, chronic diseases are often the culmination of a number of small impacts; it is not a one-exposure and one-disease equation. Olander agreed that this is a problem; current economic valuation is conducted only on those services for which a value can be quantified so most valuations are incomplete and they tend to focus on those with the largest quantifiable benefit.
CONCEPTUAL ISSUES 21 REFERENCES Bagstad, K. J., F. Villa, G. W. Johnson, and B. Voigt. 2011. ARIESâArtificial Intelligence for Ecosystem Services: A guide to models and data, version 1.0. The Aries Consortium. Available at: http://unstats.un.org/unsd/env accounting/seeaRev/meeting2013/EG13-BG-7.pdf (accessed September 13, 2013). de Groot, R. S., R. Alkemade, L. Braat, L. Hein, and L. Willemen. 2010. Challenges in integrating the concept of ecosystem services and values in landscape planning, management, and decision making. Ecological Complexity 7(3):260â272. FDA (U.S. Food and Drug Administration). 2013. Deepwater Horizon oil spill: Questions and answers. Available at: http://www.fda.gov/Food/Recalls OutbreaksEmergencies/Emergencies/ucm221563.htm (accessed September 9, 2013). Hanson, C., J. Ranganathan, C. Iceland, and J. Finisdore. 2012. The corporate ecosystem services review: Guidelines for identifying business risks and opportunities arising from ecosystem change. Version 2.0. Washington, DC: World Resources Institute. MEA (Millennium Ecosystem Assessment). 2005. Ecosystems and human well- being: Synthesis. Washington, DC: Island Press. Puget Sound Partnership. 2012. Puget Sound vital signs. Available at: http://www.psp.wa.gov/vitalsigns (accessed September 9, 2013). Sathirathai, S., and E. B. Barbier. 2001. Valuing mangrove conservation in southern Thailand. Contemporary Economic Policy 19(2):109â122. Sherrouse, B. C., J. M. Clement, and D. J. Semmens. 2011. A GIS application for assessing, mapping, and quantifying the social values of ecosystem services. Applied Geography 31(2):748â760. Tallis, H. T., T. Ricketts, E. Nelson, D. Ennaanay, S. Wolny, N. Olwero, K. Vigerstol, D. Pennington, G. Mendoza, J. Aukema, J. Foster, J. Forrest, D. Cameron, E. Lonsdorf, and C. Kennedy. 2010. InVEST 1.004 beta userâs guide. Stanford, CA: The Natural Capital Project. WHO (World Health Organization). 2013. Global environmental change. Available at: http://www.who.int/globalchange/climate/en (accessed September 9, 2013).