5_2009_ Nelson - Modeling multiple ecosystem services biodiversity conservation commodity.pdf

ECOSYSTEM SERVICES ECOSYSTEM SERVICES ECOSYSTEM SERVICES 4 Modeling multiple ecosystem services, biodiversity conservation, commodity production, and tradeoffs at landscape scales Erik Nelson1*, Guiller mo Mendoza1, James Regetz2, Stephen Polasky3, Heather Tallis1...

ECOSYSTEM SERVICES ECOSYSTEM SERVICES ECOSYSTEM SERVICES 4 Modeling multiple ecosystem services, biodiversity conservation, commodity production, and tradeoffs at landscape scales Erik Nelson1*, Guiller mo Mendoza1, James Regetz2, Stephen Polasky3, Heather Tallis1, D Richard Cameron4, Kai MA Chan5, Gr etchen C Daily6, Joshua Goldstein7, Peter M Kareiva8, Eric Lonsdorf 9, Robin Naidoo10, Taylor H Ricketts10, and M Rebecca Shaw4 Nature provides a wide range of benefits to people. There is increasing consensus about the importance of incor- porating these “ecosystem services” into resource management decisions, but quantifying the levels and values of these services has proven difficult. We use a spatially explicit modeling tool, Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), to predict changes in ecosystem services, biodiversity conservation, and com- modity production levels. We apply InVEST to stakeholder-defined scenarios of land-use/land-cover change in the Willamette Basin, Oregon. We found that scenarios that received high scores for a variety of ecosystem services also had high scores for biodiversity, suggesting there is little tradeoff between biodiversity conservation and ecosystem services. Scenarios involving more development had higher commodity production values, but lower levels of biodiversity conservation and ecosystem services. However, including payments for carbon sequestration alleviates this tradeoff. Quantifying ecosystem services in a spatially explicit manner, and analyzing tradeoffs between them, can help to make natural resource decisions more effective, efficient, and defensible. Front Ecol Environ 2009; 7(1): 4–11, doi:10.1890/080023 E cosystems generate a range of goods and services important for human well-being, collectively called ecosystem services. Over the past decade, progress has incorrectly assumes that every hectare of a given habitat type is of equal value – regardless of its quality, rarity, spa- tial configuration, size, proximity to population centers, been made in understanding how ecosystems provide ser- or the prevailing social practices and values. vices and how service provision translates into economic Furthermore, this approach does not allow for analyses of value (Daily 1997; MA 2005; NRC 2005). Yet, it has service provision and changes in value under new condi- proven difficult to move from general pronouncements tions. For example, if a wetland is converted to agricul- about the tremendous benefits nature provides to people tural land, how will this affect the provision of clean to credible, quantitative estimates of ecosystem service drinking water, downstream flooding, climate regulation, values. Spatially explicit values of services across land- and soil fertility? Without information on the impacts of scapes that might inform land-use and management deci- land-use management practices on ecosystem services sions are still lacking (Balmford et al. 2002; MA 2005). production, it is impossible to design policies or payment Without quantitative assessments, and some incentives programs that will provide the desired ecosystem services. Food for landowners to provide them, these services tend to be In contrast, under the second paradigm for generating ignored by those making land-use and land-management policy-relevant ecosystem service assessments, researchers decisions. Currently, there are two paradigms for generat- carefully model the production of a single service in a small ing ecosystem service assessments that are meant to influ- area with an “ecological production function” – how pro- ence policy decisions. Under the first paradigm, vision of that service depends on local ecological variables researchers use broad-scale assessments of multiple ser- (eg Kaiser and Roumasset 2002; Ricketts et al. 2004). vices to extrapolate a few estimates of values, based on Some of these production function approaches also use habitat types, to entire regions or the entire planet (eg market prices and non-market valuation methods to esti- Costanza et al. 1997; Troy and Wilson 2006; Turner et al. mate the economic value of the service and how that value 2007). Although simple, this “benefits transfer” approach changes under different ecological conditions. Although these methods are superior to the habitat assessment bene- 1 Natural Capital Project, Stanford University, Stanford, CA fits transfer approach, these studies lack both the scope * ([email protected]); 2National Center for Ecological Analysis and (number of services) and scale (geographic and temporal) Synthesis, University of California–Santa Barbara, Santa Barbara, to be relevant for most policy questions. CA; 3Department of Applied Economics and Department of Ecology, What is needed are approaches that combine the rigor Evolution, and Behavior, University of Minnesota, St Paul, MN; 4The of the small-scale studies with the breadth of broad-scale Nature Conservancy, San Francisco, CA; (continued on p11) assessments (see Boody et al. 2005; Jackson et al. 2005; www.fr ontiersinecology.or g © The Ecological Society of America E Nelson et al. Modeling the tradeoffs between ecosystem services and biodiversity Antle and Stoorvogel 2006; Chan et al. 5 165 km 2006; Naidoo and Ricketts 2006; Egoh et egion al. 2008; and Nelson et al. 2008 for some n ge ecor oregio Oregon initial attempts). Here, we present results Portland ion floor ec ain Ran from the application of a new, spatially ecoreg 270 km Salem explicit modeling tool, based on ecologi- Valley Mount n Range Albany 2050 Plan Trend cal production functions and economic Coast Corvalis ountai valuation methods, called Integrated des M Eugene Valuation of Ecosystem Services and Casca Tradeoffs (InVEST). We apply InVEST to three plausible land-use/land-cover (LU/LC) change scenarios in the Willamette Basin, Oregon (Figure 1). We show how these different scenarios affect hydrological services (water quality and Orchard/vineyard Young conifer storm peak mitigation), soil conserva- Grass seed Other forest Pasture/hayfield Old conifer/other natural tion, carbon sequestration, biodiversity Row crops Dense development/ Rural–residential bare ground conservation, and the value of several marketed commodities (agricultural crop products, timber harvest, and rural–resi- dential housing). We also explore the spatial patterns of ecosystem service pro- vision across the landscape under these three scenarios, highlighting synergies 1990 2050 Development and tradeoffs between multiple ecosystem services, biodiversity conservation, and market returns to landowners. 2050 Conservation  Methods InVEST consists of a suite of models that use LU/LC patterns to estimate lev- els and economic values of ecosystem Figure 1. Maps of the Willamette Basin and the land-use/land-cover (LU/LC) services, biodiversity conservation, and patterns for 1990 and under the three LU/LC change scenarios for 2050. A 500-ha Pollination the market value of commodities pro- hexagon is the spatial unit used in the LU/LC pattern maps. Each hexagon can vided by the landscape. Examples of contain more than one LU/LC. However, for illustrative purposes, we only show a ecosystem services and commodity pro- hexagon’s most dominant LU/LC. The light brown lines delineate the three ecoregions duction that InVEST can model include that intersect the Basin (Omernik 1987); from west to east, the ecoregions are the water quality, water provision for irriga- Coast Range, the Willamette Valley, and the Cascades Range. The Coast Range is a tion and hydropower, storm peak mitiga- low mountain range (122–762 m) that runs the entire Oregon coast, with three of the tion, soil conservation, carbon seques- tallest conifer species in the world supported by high annual rainfall and intensive fog tration, pollination, cultural and during the summer. The Willamette Valley incorporates terraces and the floodplain of spiritual values, recreation and tourism, the Willamette River system, and most of the agricultural and urban land use in the timber and non-timber forest products, Basin. The Cascades Range is large, steep, and high (up to 3424 m). agricultural products, and residential property values. InVEST can be run at different levels of features and data inputs for the ecosystem services, bio- complexity, making it sensitive to data availability and an diversity conservation, and commodity production understanding of system dynamics. Results can be value models. For greater detail, please refer to this reported in either biophysical or monetary terms, depend- paper’s appendix, at www.naturalcapitalproject.org/ ing on the needs of decision makers and the availability pubs/NelsonetalFrontiersAppendix.pdf. of data. However, biodiversity conservation results are reported in biophysical terms only.  Land-use/land-cover projections in the Willamette In this paper, we use a subset of the simpler InVEST Basin models and focus largely on reporting ecosystem ser- vices in biophysical terms. We run InVEST across three The base map in this study was a 1990 LU/LC map for the different projections of LU/LC change in the Willamette Basin (29 728 km2) developed by the Pacific Willamette Basin. Below, we briefly describe the major Northwest Ecosystem Research Consortium, a multi-stake- © The Ecological Society of America www.frontiersinecology.or g  Modeling the tradeoffs between ecosystem services and biodiversity E Nelson et al. 6 Water service models: water quality and storm peak mitigation 1200 In this application, we used the dis- Other forest Thousands of hectares Dense development/ charge of dissolved phosphorus into the other natural Old conifer/ Orchard/vineyard local watershed to measure water pollu- Rural–residential Pasture/hayfield 900 tion. Although this single measure Young conifer bare ground ignores many other sources of water pol- Grass seed Row crops 600 lution, it provides a proxy for non- point-source pollution. Slope, soil depth, and surface permeability were 300 used to define potential runoff by loca- tion. Areas with a greater potential runoff, less downhill natural vegetation for filtering, greater hydraulic connec- 1990 LU/LC Plan Trend Development Conservation tivity to water bodies, and LU/LC asso- ciated with the export of phosphorous Figure 2. Distribution of land area under each LU/LC category for 1990 and 2050 (ie agricultural land) have greater rates under the three LU/LC change scenarios (see Figure 1). of phosphorus discharge. Areas that have the highest water quality scores holder alliance between government agencies, non-govern- export relatively little phosphorous to waterways. mental organizations, and universities (Hulse et al. 2002; The storm peak mitigation model highlights the areas Water filtration US EPA 2002; Baker et al. 2004; www.fsl.orst.edu/ on the landscape that contribute most to potential flood- pnwerc/wrb/access.html). This alliance facilitated the cre- ing after a uniform rainfall event. The model estimates ation of three stakeholder-defined scenarios of LU/LC the volume and timing of water flow from an area to its change, from 1990 to 2050 (Baker et al. 2004). Each sce- catchment’s outlet on the Willamette River. Both the nario includes a set of spatially explicit raster grid LU/LC volume and timing of water flow across the landscape are maps (30 m x 30 m grid cells) of the Basin at 10-year affected by water retention on the land. Water retention intervals, from 2000 to 2050 (Figures 1 and 2). The three in an area is greater if its LU/LC has a rougher surface or scenarios are: provides opportunities for water infiltration. In general, as water retention rates increase in a catchment, the Plan Trend: “the expected future landscape, should cur- more that flood risk at the catchment’s outlet decreases. rent policies be implemented as written and recent Areas in a catchment that contribute less to the storm trends continue” (US EPA 2002). peak at the catchment’s outlet – because they export little Development: “a loosening of current policies, to allow water, deliver water at off-peak times, or both – have the freer rein to market forces across all components of the highest storm peak mitigation scores. landscape, but still within the range of what stakehold- ers considered plausible” (US EPA 2002). Soil conservation Conservation: placed greater emphasis on ecosystem pro- tection and restoration; however, as with the The soil conservation model uses the Universal Soil Loss Development scenario, the model still reflects “a plausible Equation (Wischmeier and Smith 1978) to predict the balance among ecological, social, and economic consid- average annual rate of soil erosion in a particular area (usu- erations, as defined by stakeholders” (US EPA 2002). ally reported in tons acre–1 yr–1; in Figure 4 we map the rel- ative change in erosion rates across space and time). The The three scenarios assume that human population in rate of soil erosion is a function of the area’s LU/LC, soil the Willamette Basin will increase from 2.0 million in type, rainfall intensity, and topography. For this study, we 1990 to 3.9 million people in 2050 (Hulse et al. 2002). assumed that rainfall intensity was homogenous across the entire landscape. In general, the model predicts greater soil  Models losses in agricultural areas and sites with steeper slopes, and lower soil losses in forested and paved areas. regions with Ecosystem services, biodiversity conservation, and lower potential soil losses received higher scores. commodity production values are a function of land characteristics and the LU/LC pattern. Models were Carbon sequestration run using the 30 m x 30 m resolution data. For report- ing and display purposes, we aggregated results to 500- We tracked the carbon stored in above- and belowground ha hexagon units (model results are given in Figures 3, biomass, soil, and harvested wood products (HWP) using 4, and 5). In general, InVEST can be run on spatial standard carbon accounting methods (Adams et al. 1999; units of any resolution. Plantinga et al. 1999; Feng 2005; Lubowski et al. 2006; www.fr ontiersinecology.or g © The Ecological Society of America E Nelson et al. Modeling the tradeoffs between ecosystem services and biodiversity Figure 3. Trends in normalized landscape-level ecosystem ser- 1.25 7 dissolved phosphorous vices, biodiversity conservation, and market value of commodity Relative reduction in 1.15 annual discharge of production for the three LU/LC change scenarios. All scores are Water quality normalized by their 1990 levels. Carbon sequestration and 1.05 commodity production values are not discounted in this figure. 0.95 Unitless 0.85 Smith et al. 2006; Kirby and Potvin 2007; Nelson et al. 2008). To determine how much carbon was stored in an 0.75 area, we estimated above- and belowground biomass and 1.25 Reduction in average soil carbon pools as a function of the area’s distribution of erosion in short tons 1.15 conservation annual rate of soil present and historic LU/LC and biomass age. We also 1.05 estimated how much timber was removed from the area 0.95 in previous time periods to determine the carbon that remained stored in HWP. The amount of carbon 0.85 Soil sequestered in an area across a particular time period is 0.75 determined by subtracting the carbon stored in the area 1.25 at the beginning of the time period from that stored in 1.15 the area at the end of the time period. management Storm peak In this study, we also estimated the social value of car- 1.05 bon sequestration (all sequestration, not just the portion 0.95 Unitless of sequestration that would be eligible for trading in a car- 0.85 bon offset market; see Watson et al. 2000). We assumed a 0.75 social value of $43 per Mg of carbon, which is the mean 1.25 value of the social cost of carbon from Tol’s (2005) survey of peer-reviewed literature. The social cost of carbon is 1.15 sequestration equal to the marginal damage associated with the release 1.05 of an additional metric ton of carbon into the atmosphere Metric tons 0.95 Carbon – or, in this case, the monetary benefit of an additional sequestered metric ton. Payments beyond 1990 were dis- 0.85 counted to reflect the decrease in monetary value over 0.75 time. We used the US Office of Management and Budget 1.25 area relationship (SAR) Countryside species– recommended rate of 7% per annum as the discount rate 1.15 conservation (US OMB 1992). In addition, we adopted the conserva- Biodiversity 1.05 tive assumption that the social value of carbon sequestra- Recreation tion will decline over time (ie in the future, the social 0.95 cost of carbon will decline at a rate of 5% per annum). 0.85 Whether the social value of carbon will decrease, 0.75 increase, or remain constant in the future is uncertain. 1.25 Market value of 1.15 Biodiversity conservation 1.05 commodity production Constant year We used a countryside species–area relationship (SAR; 0.95 Sala et al. 2005; Pereira and Daily 2006) to determine the US$2000 capacity of each LU/LC map to support a suite of 24 ver- 0.85 tebrate species that previous analysis found to be sensitive 0.75 to LU/LC change in the Willamette Basin (Polasky et al. 1990 2000 2010 2020 2030 2040 2050 Years 2008). The score for each species on a given LU/LC map depended on the amount of actual and potential habitat Plan Trend Development Conservation area provided for a species. Actual habitat area for a species was equal to the amount of LU/LC in the species’ geographic range that was compatible with its breeding tions of habitat and large penalties for losing the last few and feeding requirements. Potential habitat area was units of habitat. In this application, we used a z value of given by a species’ total mapped geographic range within 0.25 for each species. We averaged across the countryside the Willamette Basin. The countryside SAR score for SAR scores of each species to calculate an aggregate score each species was equal to the ratio of actual habitat area for each scenario. to potential habitat area raised to the power z (0 < z < 1). In order to allocate biodiversity scores spatially across Lower z values imply less of a penalty for losing small por- the landscape, we calculated a second biodiversity metric © The Ecological Society of America www.frontiersinecology.or g  Modeling the tradeoffs between ecosystem services and biodiversity E Nelson et al. 8 Water quality Soil Storm peak Carbon Biodiversity modities provided by an area. The Market value Relative reduction conservation management sequestration conservation of commodity in annual discharge Reduction in avg Metric tons Unitless 2050 relative marginal market value is equal to the aggregate production Constant year 2000 of dissolved annual rate of soil per hexagon erosion in short tons biodiversity value net present value of commodities US$ per hexagon phosphorous ratio of a hexagon per hexagon per hexagon (agricultural crops, timber, and rural–residential housing) produced in the area. The market value models Plan Trend were taken from Polasky et al. (2008). We lacked a model to value urban land use. To make fairer comparisons across scenarios, we excluded the value of commodities produced on land that was developed for urban land uses in any scenario. Development The net present value of agricul- tural crop production in an area depends on crop type, soil productiv- ity, irrigation, crop prices, and pro- duction costs. The net present value of timber production depends on the Conservation mix of tree species, soil productivity, forestry rotation time, timber price, and harvest cost. We used price and production cost estimates from 2000 for both agriculture and forestry. The Wave attenuation Greatest Greatest net present value of housing in an Decline in service/attribute production Greatest Greatest decline decline decline decline area is a function of its proximity to Greatest decline Greatest decline urban areas (Kline et al. 2001) and the area’s county, mean elevation, slope, lot size, and existing building Least decline Least decline Least decline Least decline Least decline Least decline No change No change No change No change No change No change density. We assumed that the annual service/attribute Least Least Least Least Least Improvement in Least improvement improvement improvement improvement improvement improvement per-hectare net return for rural resi- dential housing in the Basin production decreased by 0.75% for each 1% Greatest improvement Greatest improvement Greatest improvement Greatest improvement Greatest improvement Greatest improvement increase in rural residential land use in the Basin (ie elasticity of demand for rural residential housing is Figure 4. Maps of change in ecosystem services, biodiversity conservation, and market –0.75%) and that the value of rural value of commodity production from 1990 to 2050 for the three LU/LC change residential land-use increased 2% per scenarios. Carbon sequestration and commodity production values are not discounted. annum. We used a discount rate of 7% per annum to compute the net that could be applied to distinct areas on the landscape present values of commodity production across time. (countryside SAR applies only at the landscape level). This metric estimated an area’s relative contribution to  Results the sustainability of each species. The marginal biodiver- sity value (MBV) of an area measures the value of habitat Of the three LU/LC change scenarios, the Conservation in the area for all species under consideration, relative to scenario produced the largest gains (or the smallest losses) the composite value of habitat available to all species in ecosystem services and biodiversity conservation (Figure across the whole landscape. We then calculated the rela- 3). Under the Conservation scenario, carbon sequestration, tive MBV (the RMBV), a modified version of MBV, to water quality, and soil conservation scores increased sub- measure the change in an area’s value over time, and stantially. Carbon sequestration also increased under the reported the ratio of this number to the area’s MBV value Plan Trend and Development scenarios, although less on the 1990 LU/LC map. steeply, mainly because of sequestration losses in the lower elevations of the Cascade Mountains as a result of rural res- Commodity production value idential development and timber production (Figure 4). Water quality and potential soil conservation changed In addition to the ecosystem services and biodiversity only slightly in the Plan Trend and Development scenarios, conservation, we also estimated the market value of com- but improved under the Conservation scenario, because of www.fr ontiersinecology.or g © The Ecological Society of America E Nelson et al. Modeling the tradeoffs between ecosystem services and biodiversity replacement of agricultural land with 9 forests, prairies, and other land uses on 0.60 the Basin floor (Figure 1). Countryside SAR score in 2050 Agricultural, timber, All commodities Storm peak mitigation scores declined and rural–residential and carbon slightly under all three scenarios (Figure 0.59 commodities sequestration 3), but the Conservation scenario exhib- Conservation ited the smallest reduction. Reductions 0.58 in hexagon storm peak management scores (indicative of increased flood risk at the hexagon’s catchment outlet on 0.57 the Willamette River, all else being equal) were greatest under the 0.56 Development Development scenario, which had the Plan Trend largest increase in impervious surface area of any of the scenarios. Outside of 0.55 developing areas on the Basin floor, 14.5 15.0 15.5 16.0 16.5 storm peak management scores were Net present market value of 1990–2050 largely unchanged (Figure 4). Landscape-level biodiversity conser- commodity production (billions of US$) vation scores also showed only small changes through time under each of the Figure 5. Tradeoffs between market values of commodity production and biodiversity three scenarios. The 24-species coun- conservation on the landscape between 1990 and 2050, excluding (circles) and tryside SAR showed a small increase including (triangles) the market value of carbon sequestration (we assume that the under the Conservation scenario, but social value of carbon is equal to the market value of sequestered carbon). The x axis declined slightly under both the Plan measures the total discounted value of commodities, whereas the y axis measures the Trend and Development scenarios biodiversity (ie countryside SAR) score for 2050. (Figure 3). The areas immediately sur- rounding urban areas saw the greatest biodiversity losses, as estimate, since carbon prices on the European carbon measured by RMBV ratios. Some of the greatest increases in market were $133–162 Mg–1 of sequestered carbon, at an RMBV ratios occurred in the Coast Mountain Range and exchange rate of US$1.58–€1 in July 2008, and toward the southern end of the valley floor (Figure 4). $88–112 Mg–1 of sequestered carbon, at an exchange rate Despite widespread declines in RMBV ratios across the of US$1.33–€1 in October 2008). The total present value landscape in the Plan Trend and Development scenarios, the of carbon sequestration on the landscape from 1990 to declines were not great enough to greatly reduce the 24- 2050 was $1.6 billion, $0.9 billion, and $0.8 billion, species countryside SAR score under either scenario. The under the Conservation, Plan Trend, and Development sce- use of a higher z value in the countryside SAR calculation narios, respectively (and $1.5 billion, $0.8 billion and would result in greater biodiversity conservation score $0.7 billion, respectively, if we only applied a market declines in the Plan Trend and Development scenarios. value to 50% of HWP carbon sequestration on the land- The aggregate market value of commodities produced on scape). If these carbon sequestration values are added to the landscape was the only measure where the Conservation aggregate market value of commodities for each scenario, scenario did not outperform the Plan Trend and then Conservation generates more monetary value than Development scenarios (Figure 3). The market value of Plan Trend and Development ($16.38 versus $16.16 or commodity production increased in many areas under the $16.07 billion [Figure 5]; or $16.27 versus $16.05 or Food Plan Trend and Development scenarios, as a result of both $15.96 billion, if we only applied a market value to 50% increased residential development and more intensive tim- of HWP carbon sequestration on the landscape). If pay- ber harvesting (Baker et al. 2004; Figure 4). Although the ments were made for the other ecosystem services, the market value of commodity production declined in a value of the Conservation scenario would increase even majority of areas under the Conservation scenario (4143 out further relative to the other two scenarios. of 6214 hexagons), aggregate market value of commodity production summed over the whole region increased,  Discussion because the high value of rural residential development near cities more than compensated for losses elsewhere. We applied the InVEST model to predict the provision of Given the emerging interest in carbon markets, we cal- ecosystem services, biodiversity conservation, and the culated the aggregate market value of carbon sequestra- market value of commodities across space and time for tion under the three scenarios. We assumed the market three contrasting scenarios of future LU/LC change. This value of carbon sequestration was equal to its social value research contributes to an emerging literature that of $43 Mg–1 of sequestered carbon (this may be an under- attempts to quantify the value of multiple ecosystem ser- © The Ecological Society of America www.frontiersinecology.or g  Modeling the tradeoffs between ecosystem services and biodiversity E Nelson et al. 10 vices at a broad scale (geographic and temporal) by way will be determined by local patterns of land use and popu- of ecological production functions and economic valua- lation density. For example, in a flooding-prone watershed tion methods. Analyzing how ecosystem service provision in which few people or farms occur, flood mitigation ser- and value change under alternative realistic scenarios dis- vices will provide relatively little benefit to people. tinguishes our approach from the well known maps of Another important caveat to our analysis is that we did “total” value (ie benefits transfer) that can be produced not include the market value of commodities generated for a site (Troy and Wilson 2006), a state (Costanza et al. in urbanized areas in any scenario (this was done to keep 2006), or the world (Costanza et al. 1997). the base land area in the market value model equal across Combining multiple outputs under different LU/LC sce- all scenarios). Because market returns on urban land tend narios demonstrates the extent of the synergies or trade- to be higher than returns for other land uses, we probably offs among these outputs. In the Willamette Basin appli- underestimated the aggregate value of marketed com- cation, we found little evidence of tradeoffs between modities for scenarios that experience greater urbaniza- ecosystem services and biodiversity conservation: scenar- tion (ie the Development scenario). In general, for land- ios that enhance biodiversity conservation also enhance use decisions involving a choice between intensive urban the production of ecosystem services. Fears that a focus on development and conservation, development values ecosystem services will fail to help us achieve biodiversity might very well overwhelm the ecosystem services values conservation goals (eg Terborgh 1999; McCauley 2006) that could be generated by conserving the land. We were not borne out in this case. A negative correlation should not expect existing markets or market valuation of between commodity production values and (1) ecosystem ecosystem services inevitably to favor conservation, espe- services and (2) biodiversity conservation is the one clear cially in high-value urban areas. The kinds of analyses we tradeoff we found. These results indicate that when show here, however, make transparent the tradeoffs landowner decisions are based solely on market returns between ecosystem services, biodiversity conservation, (without payments for ecosystem services), they will tend and market returns, and that transparency alone is desir- to generate LU/LC patterns with lower provision of able in engaging stakeholders and decision makers. ecosystem services and biodiversity conservation. Another intriguing outcome of our analyses was that Even this tradeoff, however, can be modified by policy the scenarios did not produce more marked differences in interventions. If markets for carbon sequestration the provision of ecosystem services and biodiversity con- emerge, payments for sequestered carbon may make it servation. This may be a reflection of the relatively mod- more profitable for landowners to choose LU/LC favoring est LU/LC change under the scenarios considered here: conservation. In this application, payments for carbon “The stakeholder advisory group, which oversaw design sequestration cause the aggregate market value of the of the future scenarios, did not consider…drastic land- Conservation scenario to be greater than the aggregate scape alterations plausible, given Oregon’s history of Recreation market value of the Development and Plan Trend scenarios resource protection, social behaviors, and land-ownership (Figure 5). This result doesn’t necessarily mean that the patterns” (Baker et al. 2004). Indeed, using more complex Conservation scenario would emerge if payments for car- habitat–species relationship data, Schumaker et al. bon sequestration were made. The actual LU/LC pattern (2004) also found little change in a biodiversity status that emerges under a carbon market will depend on the measure (essentially a countryside SAR score with 279 prices paid for sequestration, which carbon pools are eli- species and a z value of 1) from 1990 to 2050 across the gible for payment, and the individual preferences of three scenarios. The Willamette Basin has large tracts of landowners. However, it is more likely that land-use contiguous forests in the Cascade and Coastal Mountain choices with carbon payments, especially in rural areas, Ranges that remained relatively unchanged cross all would generate a spatial pattern more like the three scenarios. Most of these areas are not suitable for Conservation scenario than those of the Development and agriculture or urban development. They probably act as a Plan Trend scenarios. Payments for water quality, soil con- buffer for maintaining provision of ecosystem services servation, and storm peak mitigation would strengthen and biodiversity, no matter how great the changes on the the likelihood that LU/LC patterns similar to those Basin floor (Figures 1, 2, and 4). We expect the modeling described in the Conservation scenario would emerge. and valuation approach illustrated here to reveal more Before payments for these ecosystem services are insti- striking tradeoffs between conservation and development tuted, however, clear links need to be made between their in rapidly developing regions. biophysical provision and their ultimate use by people. Although the structure of the models presented here Other than carbon sequestration, we have only modeled can, in principle, include drivers besides land-use change biophysical production of ecosystem services. The crucial (eg climate change), we have not included these in the second step is to determine how much of this production analysis to date. Furthermore, there may be important is actually of value to people and where that value is cap- feedback effects, such as the amenity value of conserved tured. In this study, we have done this with carbon seques- land, that increases development pressure on land near tration (we assumed that all sequestration provides value conserved areas. Including changes in climate, technol- to all people in the world). For other services, use values ogy, market prices, human population, and feedback www.fr ontiersinecology.or g © The Ecological Society of America E Nelson et al. Modeling the tradeoffs between ecosystem services and biodiversity McCauley D. 2006. Selling out on nature. Nature 443: 26–27. effects – all of which are likely to drive the ecological, Naidoo R and Ricketts TH. 2006. Mapping the economic costs and 11 social, and economic relationships that determine the benefits of conservation. PLoS Biol 4: 2153–64. value of ecosystem services in the future – is an essential NRC (National Research Council). 2005. Valuing ecosystem service: next step in the application of InVEST. towards better environmental decision-making. Washington, DC: National Academies Press. Nelson E, Polasky S, Lewis D, et al. 2008. Efficiency of incentives to  Acknowledgements jointly increase carbon sequestration and species conservation on a landscape. P Natl Acad Sci USA 105: 9471-9476. The authors thank D White, J Lawler, J Kagan, S Wolny, Omernik JM 1987. 2008. Ecoregions of the conterminous United N Sandhu, S White, A Balmford, N Burgess, and M States. Map (scale 1:7 500 000). Ann Assoc Am Geogr 77: Rouget for help in developing, testing, running, and pro- 118–25. Pereira HM and Daily GC. 2006. 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