The Empirics of Wetland Valuation: A Comprehensive Summary and a Meta-Analysis of the Literature

Wetlands are highly productive ecosystems, providing a number of goods and services that are of value to people. The open-access nature and the public-good characteristics of wetlands often result in these regions being undervalued in decisions relating to their use and conservation. There is now a substantial literature on wetland valuation, including two meta-analyses that examine subsets of the available wetland valuation literature. We collected over 190 wetland valuation studies, providing 215 value observations, in order to present a more comprehensive meta-analysis of the valuation literature that includes tropical wetlands (e.g., mangroves), estimates from diverse valuation methodologies, and a broader range of wetland services (e.g., biodiversity value). We also aim for a more comprehensive geographical coverage. We find that socio-economic variables, such as income and population density, that are often omitted from such analyses are important in explaining wetland value. We also assess the prospects for using this analysis for out-of-sample value transfer, and find average transfer errors of 74%, with just under one-fifth of the transfers showing errors of 10% or less. † This paper has not been submitted elsewhere in identical or similar form, nor will it be during the first three months after its submission to the Publisher.     

Valuing water level changes in reservoirs using two stated preference approaches: An exploration of validity

The combination of travel cost (TCM) and contingent behaviour (CB) methods is a relatively new research avenue in the recreational valuation community. Contrary to simple TCM applications, TCM-CB facilitates the ex ante valuation of marginal welfare effects resulting from environmental quality or quantity changes, similar to the contingent valuation method (CV). Even though TCM-CB is highly policy relevant, i.e. to inform changes in management regimes at recreational sites, the validity of estimates has hardly received any attention and little is known about the performance of TCM-CB compared to CV. In this paper, TCM-CB and CV are explored with respect to several validity tests in a case study on the recreational effects of water level changes in a reservoir. Overall, the findings reveal that TCM-CB and CV perform equally well in terms of theoretical validity, but that the marginal recreational value varies significantly between the two methods. We also observe that both methods face similar internal difficulties with respect to the stability of values when the order of a set of valuation questions is changed.     

Valuing water quality improvements in the United States using meta-analysis: Is the glass half-full or half-empty for national policy analysis?

The literature estimating the economic value for water quality changes has grown considerably over the last 30 years, resulting in an expanded pool of information potentially available to support national and regional policy analysis. Using 131 willingness to pay estimates from 18 studies that use a similar definition of water quality, we performed a meta-regression analysis and found mixed results. We find that WTP varies in systematic and expected ways with respect to factors such as the size of the water quality changes, average household income, and use/nonuse characteristics of respondents. As a whole, we conclude that our meta-regression results provide a reasonable basis for estimating expected WTP values for defined changes in water quality. However, despite a large number of existing economic valuation studies, relatively few could be meaningfully combined through meta-analysis due to heterogeneity in the commodities being valued in the original studies. Based on these findings, we provide recommendations for future research, including suggestions regarding more standardized approaches for defining water quality and reporting information in valuation studies.     

Using Meta-Analysis and GIS for Value Transfer and Scaling Up: Valuing Climate Change Induced Losses of European Wetlands

There is growing policy and academic interest in transferring ecosystem service values from existing valuation studies to other ecosystem sites at a large geographic scale. Despite the evident policy demand for this combined transfer and “scaling up” of values, an approach to value transfer that addresses the challenges inherent in assessing ecosystem changes at a national or regional level is not available. This paper proposes a methodology for scaling up ecosystem service values to estimate the welfare effects of ecosystem change at this larger geographical scale. The methodology is illustrated by applying it to value the impact of climate change on European wetlands for the period 2000–2050. The proposed methodology makes use of meta-analysis to produce a value function. The parameters of the value function include spatial variables on wetland size and abundance, GDP per capita, and population. A geographic information system is used to construct a database of wetland sites in the case study region with information on these spatial variables. Site-specific ecosystem service values are subsequently estimated using the meta-analytic value function. The proposed method is shown to enable the adjustment of transferred values to reflect variation in important spatial variables and to account for changes in the stock of ecosystems.     

Evaluating the effects of area closure for recreational fishing in a coral reef ecosystem: The benefits of an integrated economic and biophysical modeling

This paper presents an integrated agent-based model of recreational fishing behavior within a reef ecosystem as a platform for the evaluation of recreational fishing management strategies. Angler behavior is described using econometrically estimated site choice models, with site choice among anglers driven by site attributes and angler characteristics. The biophysical model represents the marine reef environment as a system with different trophic levels identifying algal and coral growth as well as two types of fish (piscivores and herbivores). Ecosystem dynamics are driven by interactions within the trophic levels and interaction between fish populations and fishing activities.The model is used to simulate recreational fishing activities and their interactions with the environment. Recreational fishing sites from the Ningaloo Marine Park, an iconic coral reef system in Western Australia, are used as a case study. A set of management strategies, including “business-as-usual” and different site closure durations, are assessed for two different levels of fishing pressures. The results show that not only the effectiveness but also the distribution of management impacts across space and over time can be very different from what one would expect without the benefit of integrated modeling.     

Economic Assessment of Forest Ecosystem Services Losses: Cost of Policy Inaction

This paper presents a bottom-up methodological framework for estimating some of the key ecosystem services provided by forests biomes worldwide. We consider the provision of wood and non-wood forest products, recreation and passive use services, and carbon sequestration. The valuation framework derives per hectare estimates by applying meta-analysis, value-transfer and scaling-up procedures in order to control for the existing heterogeneities across world regions and forest biomes. The first part of the study estimates stock values per hectare for each forest ecosystem service in the baseline year 2000 and in the year 2050. Results differ per geographical region and biome. Carbon stocks represent, on average, the highest value per hectare, followed by provisioning services, passive use and recreational values respectively. The second part provides an estimation of the welfare loss (or gain) associated with policy inaction in the period 2000–2050 leading to a change in the forest area. Welfare results are mixed and require a careful interpretation, ranging from a worldwide annual benefit of + 0.03% of 2050 GDP to an annual loss of −0.13%. The highest damage is expected in Brazil due to the increasing deforestation taking place in tropical natural forests, which is causing a considerable loss of carbon stocks.     

The Value of Urban Green Space in Britain: A Methodological Framework for Spatially Referenced Benefit Transfer

A meta-analysis of studies valuing urban greenspace in the UK is undertaken to yield spatially sensitive marginal value functions. A geographical information system (GIS) is used to apply these functions to spatial data detailing the location of such greenspace resources in five British cities. Changes in monetary values are computed for the six future scenarios used in the UK National Ecosystem Assessment for the period 2010–2060. Different degrees of substitutability between urban greenspaces are considered. These findings are then extrapolated to all major British cities to obtain per household and aggregate valuation estimates for each scenario both with and without distributional weights. While subject to a number of shortcomings in both data availability and methodology, this represents the first systematic and comprehensive attempt to value marginal changes in urban greenspace while accounting for spatial heterogeneity.     

Estimating the economic benefits of acidic rock drainage clean up using cost shares

This paper reports the results of a stated preference study that estimates the economic value for cleaning up acid rock drainage in Colorado's Snake River watershed. In contrast to much of the existing literature, the present study emphasizes benefit estimation for three implementing projects rather than benefit estimation for general changes in water quality or large scale water quality policy. The focus on implementing projects delivers information that is specifically relevant to current decisions being faced in the watershed. While valuation questions in most stated preference studies present costs that have no relation to actual project costs, this study presents a new cost share approach. Project costs are estimated and then valuation questions present different local cost shares to subjects. This approach facilitates stated cost variation necessary for estimating the mean of the distribution of project values without resorting to experimentally designed, fictitious stated costs. In addition to estimating the mean value, which facilitates benefit cost analysis, the study also provides median value estimates, which provide insights into the political feasibility of these projects. Study results suggest that local cost shares on the order of 20%-40%, depending on the project, are politically feasible.     

Deriving values for the ecological support function of wildlife: An indirect valuation approach

We describe a method that combines economic willingness-to-pay estimates for higher trophic-level species with basic information available about ecosystem relationships to derive estimates of partial willingness-to-pay for lower level species that might be of direct policy interest. This method is intended as a quasi-benefit transfer method for use in benefit–cost analysis. Our method makes it possible to establish partial willingness-to-pay estimates for the large number of species of immediate or potential policy interest using only data available in non-market valuation and biology and ecology literature. We provide a partial estimation of indirect values for the predator–prey relationships that support golden eagles in the Snake River Bird of Prey area as an example of how to operationalize our approach.     

Consumption Externalities in a Commercial Fishery: the Queensland Beam Trawl Fishery

Demand and contingent valuation models are used to analyze survey data obtained from a sample of recreational boat and shore fishers in southern Queensland. The value of the recreational fishery to the average fisher in the sample and the value of marginal increases in catches of target species are estimated. These estimates are used to calculate the value of Pigovian taxes representing the marginal cost of catch and congestion externalities imposed by the beam trawl fishery on the recreational fishery. The results suggest that the cost of these externalities does not justify the closure of the beam trawl fishery.