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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California VIII. Human-Use Values—Economics, Recreation, and Aesthetics A. BACKGROUND The environmental resources contained in parks, conservation land, and wilderness areas generate several recognized types of economic value,1 including those that derive from recreation, economic activity associated with use and maintenance, production of consumption goods, property value enhancement, ecosystem services, and non-use values (NRC, 1994, 2004b). Some of these values can, in principle, be derived from information about market transactions; for example, the change in property values due to nearby environmental amenities can be estimated from market data. Others, such as recreational and non-use values,2 require the careful application of “contingent valuation” survey techniques (Mitchell and Carson, 1989; Arrow et al., 1993) and travel cost analyses (Loomis and Walsh, 1997). Recreational value is the non-market value realized by people who use the park or wilderness area for recreation. In most cases, access to recreational amenities of parks and wilderness areas is not purchased directly in a market where prices can be observed (Bateman and Langford, 1 Economic values are defined here as anthropocentric; that is, they are determined by reference to values received or perceived by human beings. It is possible to take the position that environmental resources also give rise to nonanthropocentric values that emerge from the moral interests or rights of nonhuman species (Foster, 1997; NRC, 2004b). The committee constrains its discussion here to anthropocentric economic values. 2 Non-use values are also referred to as “passive-use values.”
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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California 1997; Shechter et al., 1998). As a result, recreational values are often estimated using techniques, such as the travel cost method or contingent valuation (Fredman and Emmelin, 2001; Hanley et al., 2003; Herath and Kennedy, 2004). The same techniques can be applied to valuing cultural heritage features within an area visited for recreation (Navrud and Ready, 2002; Sattout et al., 2007). Estimates of the recreational value generated per person-day in a wilderness area are typically on the order of $50 (Walsh et al., 1992; Loomis et al., 1998; Loomis, 2000). Economic activity associated with use and maintenance of a park or wilderness area generates economic impacts in surrounding communities through public spending on park and wilderness management and maintenance (e.g., employee salaries) and through private spending by visitors in restaurants, hotels, and shops in the course of travel to the park or wilderness area. Property value enhancement refers to the increase in the market value of private property in the vicinity of park, wilderness, or conservation land. Consumption goods produced within the conservation area may be timber in a multi-use national forest or cattle and oysters in a setting such as the Point Reyes National Seashore. Ecosystem services provided by aquatic and related terrestrial ecosystems generally include nutrient recycling, habitat for plants and animals, flood control, and water supply (NRC, 2004b). The ecosystem service most closely associated with marine estuaries and seagrass beds is nutrient recycling; others include habitat and refuge, food production, and disturbance (i.e., storm or weather) regulation (Costanza et al., 1997). Although ecosystem services are usually not traded in markets, it is possible to estimate their economic value using shadow prices (Kaiser and Roumasset, 2002). The ecosystem resources embodied by Drakes Estero are fairly well understood and are described in the previous chapters (I through VII) of this report. The ecosystem services provided by the specific resources in Drakes Estero have not been quantified in either ecological or economic terms. Non-use values of wilderness were first formally articulated by Weisbrod (1964), who suggested that undeveloped forest areas might give rise to option value, and by Krutilla (1967), who added the categories of existence and bequest values. First efforts to estimate these values systematically for wilderness areas were carried out by Walsh et al. (1984) in a study of Colorado wilderness areas. Option value is the value attributable to the opportunity at some point in the future to make decisions about the disposition or conservation of an asset (Forsyth, 2000; Bulte et al., 2002; Bosetti et al., 2004; Buttle and Rondleau, 2004). Existence value refers to the non-use value derived by people from the knowledge that something exists, irrespective of whether they (or anyone else) ever make use of it or
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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California even see it (Hageman, 1985; McFadden, 1994; Blomquist and Whitehead, 1995; Loomis and White, 1996; Randall and Stoll, 1999). Bequest value is the satisfaction derived from preserving something for future generations (Greenley et al., 1981; Beaumont et al., 2007). All of these values may be lost, to some degree, when an area of wilderness is developed or a species is driven to extinction. Existence and bequest values are typically assessed using contingent valuation techniques (e.g., questionnaires, surveys, interviews) (Keith et al., 1996; McDaniels and Roessler, 1998). Estimates of non-use values generated by designating a given area as wilderness (as opposed to leaving it open to development or multi-purpose access) are typically on the order of $10 to $100 per household per year or a present value on the order of $100 to $1,000 per acre of wilderness (Walsh et al., 1984; Pope and Jones, 1990; Gilbert et al., 1992). B. WHAT IS THE BODY OF SCIENTIFIC STUDIES ON THE IMPACT OF THE OYSTER FARM ON DRAKES ESTERO? No social science research has been carried out to quantify or estimate the effects of oyster farming on the economic values generated by Drakes Estero or the Point Reyes National Seashore. Similarly, the recreation and non-use values generated by, and the importance of aesthetics to, the human uses of Drakes Estero remain unstudied. Of the more than 2 million annual visitors reported by NPS to visit the Point Reyes National Seashore (Figure 9), it is not known how many FIGURE 9. Trends in number of annual visitors to Point Reyes National Seashore (Source: National Park Service).
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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California spend time on or at the estero. The only vehicle access to the estero is a road to the oyster farm site on Schooner Bay, which is also the only kayak launching point. Alternatively, the estero may be reached via hiking trails from the Bull Point and Drakes Estero trailheads on Sir Francis Drake Boulevard and via hiking trails from the Muddy Hollow trailhead on Limantour Road. Baltan (2006) suggests that recreational use of Drakes Estero has increased since the early 1990s, particularly for kayaking and canoeing. Some 460 boaters participated in commercially organized kayak tours of Drakes Estero in 2005 (Baltan, 2006, citing personal communication with Kevin McKay, NPS); other boaters used the estero independently. Ten companies offered kayak tours of the estero under permits granted by NPS in 2005 (Baltan, 2006). These tours are not permitted during the harbor seal pupping season from March 1 to June 30. Unpublished data from the Point Reyes National Seashore visitor surveys carried out by students from Sonoma State University in 1997 and 1998 obtained from the Point Reyes National Seashore suggest that as many as 3% of the visitors surveyed planned to kayak during their visit to the Point Reyes National Seashore, but these surveys were not designed to capture a representative sample of all visitors to the Point Reyes National Seashore. Moreover, they do not provide information specifically about how many of these kayakers used Drakes Estero. The oyster farming operation employs 30–40 people and produced 436,848 pounds of oyster meats in 2008 (Kevin Lunny, personal communication 5 March 2009 and California Department of Fish and Game) at an estimated value on the order of $2,000,000 based on NOAA’s commercial landing statistics and the California Department of Fish and Game aquaculture survey database. Total May 2007 employment of agricultural workers in Marin, San Francisco, and San Mateo Counties was 1,510, with average annual earnings per worker of $26,000 (U.S. Bureau of Labor Statistics, 2009). This suggests that DBOC accounts for 2–3% of agricultural employment in the greater San Francisco-San Mateo-Redwood City metropolitan area and generates an annual payroll of about $1 million. C. WHAT EFFECTS CAN BE DIRECTLY DEMONSTRATED BY RESEARCH CONDUCTED IN DRAKES ESTERO ITSELF? No effects of the oyster farming operation can be directly demonstrated from social science research carried out on Drakes Estero because no such research has been done.
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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California D. WHAT EFFECTS CAN REASONABLY BE INFERRED FROM RESEARCH CONDUCTED IN SIMILAR ECOSYSTEMS? The oyster farming operation in Drakes Estero can be reasonably inferred on the basis of logical deduction to: (1) have a positive effect on total employment, tax revenue, and local food production in Marin County; (2) continue an historical use of the estero for shellfish mariculture, which likely enhances some visitors’ experience in the estero and preserves a piece of local and regional culture and history; (3) introduce structures and activities into the estero that may affect negatively the wilderness experience and the aesthetic value of the estero for some visitors, and may detract from the existence value of the estero for those who value wilderness with minimal human structures and activities; (4) probably have no discernible effect on the aggregate recreational value (e.g., hiking, kayaking) of the estero; and (5) probably have a slight negative effect on non-use values associated with the estero. At approximately 2–2.5 million visitors per year, the Point Reyes National Seashore may be estimated to generate on the order of $100 million per year in recreational value (see section VIII.A). Drakes Estero contributes an unknown fraction of this total. It is not known whether the presence of the oyster farming operation has a significant effect on the number of annual visitors to the Point Reyes National Seashore and Drakes Estero. It seems plausible that the net effect of the oyster farm on the Point Reyes National Seashore/Drakes Estero visitor counts is positive since some visitors are reported to come to Drakes Estero in part to purchase oysters from DBOC, and it seems unlikely that visitors are deterred from coming because of the oyster farm. The level of economic activity in surrounding communities associated with the operation, maintenance, and use of the Point Reyes National Seashore and Drakes Estero has not been estimated. It is unlikely that the oyster farming operation has a significant effect on this, although there could be a modest positive effect if DBOC is contributing to higher numbers of visitors to the Point Reyes National Seashore (see above). Property-value enhancement for private lands in the vicinity of the Point Reyes National Seashore from the existence of the national seashore has not been measured, but is likely to be positive. It is unlikely that this property-value enhancement is affected in any significant way by the presence of oyster farming operations in Drakes Estero. DBOC produced about 467,000 and 437,000 pounds of oyster meats per year in 2007 and 2008 respectively. In the process, oyster culture in the estero generates an estimated $1 million in annual payroll and 2–3% of the roughly 1,500 agricultural jobs in the San Francisco-San Mateo-Redwood City metropolitan area. In a synthesis of prior studies (i.e., Daily, 1997; Pimm, 1997), Costanza
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Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California et al. (1997)3 estimated the biogeochemical-ecosystem value of marine estuaries at $22,422 per hectare per year and of seagrass and algae beds at $19,004 per hectare per year (in 1994 dollars). These are equivalent to $12,695 per acre per year for estuaries and $10,759 per acre per year for seagrass and algae beds in 2007 dollars. Using the average of these values, and applying it to Drakes Estero (2,270 acres at high tide), suggests that the estero may generate ecosystem services on the order of $26.6 million per year. There is not sufficient quantitative information to assess the effect of oyster farming on ecosystem services provided by the estero, but the net effect could be positive due to the added filtering capacity and nutrient recycling provided by the oysters. From the non-use values estimated for wilderness areas in other parts of the United States, it may be inferred that Drakes Estero and the Point Reyes National Seashore have significant existence, option, and bequest value as protected environmental resources. Most published estimates of non-use value of protected lands are attached to larger areas (millions of acres) than Drakes Estero or the Point Reyes National Seashore, and they deal with the value of preserving wilderness from development. These estimates do not provide much information that can be readily transferred to a 2,000-acre wilderness within a larger park, where the development in question (oyster culture) has a relatively small physical footprint. It is likely that the presence of oyster farming in Drakes Estero has a marginal negative effect on the non-use values of the estero. 3 These estimates are for marginal values of ecosystem services. There has been considerable criticism of the Costanza et al. (1997) approach to scaling from marginal values to global values. The committee is not engaged in scaling to global values here; it is looking closely at a particular estuary. In this situation, it is appropriate to apply the marginal value estimates.