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.     

Valuation and management of wetland ecosystems

We recently completed a study of wetland values in coastal Louisiana that employed both willingness-to-pay and energy analysis-based methodologies and were able to bracket a range of values within which we feel fairly confident the true value lies. However, a large amount of uncertainty remains. Our current estimates of the total prsent value of an average acre of natural wetlands in Louisiana are US$2429–6400 per acre (assuming an 8% discount rate) to $8977–17000 per acre (assuming a 3% discount rate). At the lowest value, the current annual rate of loss of Louisiana wetlands (50 sq miles per year) is worth about $77 million. At the largest value it is worth about $544 million.In this paper we (a) discuss the fundamental theoretical and practical problems underlying natural resources valuation; (b) summarize our methods and findings for Louisiana wetlands; and (c) elaborate on some of the more recalcitrant problems attending applied natural resource valuation, including discounting and dealing with uncertainty and imprecision.The discount rate makes more difference in the final result than any other one factor, and yet there is much disagreement about the appropriate approach to discounting natural resources. We discuss the discounting problem as applied to natural resources and argue for lower discount rates for valuing renewable natural resources than apply for other aspects of the economy.It now seems clear that no reasonable amount of effort will produce very precise estimates of wetland values, and we suspect this is also the case for several other classes of natural resources. We elaborate a Wetlands Asurance Bonding System to address these problems.     

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.     

The value of wetlands: importance of scale and landscape setting

Wetlands have value because their functions have proved to be useful to humans. The unit value for some wetlands also increases with human development (agriculture and urban) because of increased use and/or increased scarcity. Yet, paradoxically, its functions can easily be overwhelmed in areas of heavy human development, thus lessening those values. Thus wetlands appear to work best in the landscape as spatially distributed systems. Also, the value is partially dependent on where they are found in the landscape, e.g., the degree to which a wetland is open to hydrologic and biological fluxes with other systems, including urban and agricultural landscapes. A paradox of assigning values to wetlands and other ecosystems is that it can argue for the replacement of one system with another if a landscape view is not taken. Estimates of percent of landscape for various functions, e.g. water quality or flood control, are presented. It is suggested that a range of 3–7% of temperate-zone watersheds should be in wetlands to provide adequate flood control and water quality values for the landscape.     

Approaches to valuing the hidden hydrological services of wetland ecosystems

This paper investigates the role of the production function approach in capturing the value of hydrological services of wetland ecosystems. Hydrological research in the Hadejia-Nguru wetlands in northern Nigeria suggests that the major role of the wet season inundation of the wetlands is in recharging the underlying aquifers. This paper shows that the hydrological services extend beyond direct use values, and have a significant economic value associated with them. Whereas the direct benefits provided by the wetlands, such as floodplain agriculture, fishing and forestry, have previously been assessed, this paper synthesizes the results of two approaches to capture the value of indirect benefits derived from the role of the wetlands in replenishing and maintaining groundwater resources within the wetland area.     

东道国政治风险对企业对外直接投资绩效的影响——基于企业风险管理能力与东道国自由裁量权的联合调节效应

小微湿地是城市景观中的重要组成部分,研究其空 间分布特征,并从文化与生态2个方面定量估算其服务价值 对引导改善城市人居环境具有重要意义。以南昌市中心城区 小微湿地为研究对象,借助ArcGIS平台开展小微湿地的空间 核密度分析,揭示小微湿地的空间分布特征;以条件价值法 (CVM)、影子工程法(SPA)和市场价值法(MVM)等分别计 量文化与生态服务价值。结果表明：城市小微湿地空间分布不 均衡,主要集中在公园和居住区的差异性格局,受城市规划建 设影响显著;借助CVM方法计量小微湿地的水资源保护、游 憩、景观、科普教育的文化服务价值,通过SPA、MVM等方 法对小微湿地涵养水源、调蓄雨洪、固碳、释氧、降尘等生态 价值进行了估算,研究区2019年小微湿地文化生态服务总价 值为1.469亿元。与其他类型的生态系统相比,小微湿地具有更 高的单位面积文化生态服务价值量,约19.74万元/(hm2 ·a)。 基于以上结果提出对策,旨在构建可持续的城市小微湿地系 统,为城市规划和建设提供新的途径和参考。     

Ecosystem services value of wetland in Suzhou Taihu Lake

Based on a comprehensive analysis on various classifications of natural resource values,this paper summarizes an ecological services system of constructed wetland（CW） ecosystems for the accounting of ecological economic value.With the research,the wetland ecosystem services can be classified into six categories,that is waste treatment,food and material production,water supply,gas regulations,disturbance and water regulations,habitat and refuge provision.For decision making in terms of environmental economics for wetland construction,ecosystem services value for the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort is accounted for 7,088,769 USD/yr through Environmental Economics Analysis.Ecosystem services value of waste treatment is 825,000 USD/yr,that of food and material production is 1,430 USD/yr,that of water supply is 4,752,000 USD/yr,that of gas regulation is 2,251USD/yr,that of disturbance and water regulations is 1,3721 USD/yr,and that of habitat and refuge provision value is 1,494,367 USD/yr.The ecosystem services values of a pilot constructed wetland in Suzhou are compared with those of other wetlands as a mean and of a typical human-interfered wetland in Wenzhou of China.Results show that in both finite and infinite time horizons considered,the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort has the largest services value.This paper analyzes all the probability that may weaken the value of the Suzhou Taihu Wetland in order to provide some advices for the wetland protection.     

Meta-Functional Benefit Transfer for Wetland Valuation: Making the Most of Small Samples

This study applies functional Benefit Transfer via Meta-Regression Modeling to derive valuation estimates for wetlands in an actual policy setting of proposed groundwater transfers in Eastern Nevada. We illustrate how Bayesian estimation techniques can be used to overcome small sample problems notoriously present in Meta-functional Benefit Transfer. The highlights of our methodology are: (i) The hierarchical modeling of heteroskedasticity; (ii) The ability to incorporate additional information via refined priors; and (ii) The derivation of measures of model performance with the corresponding option of model-averaged Benefit Transfer predictions. Our results indicate that economic losses associated with the disappearance of these wetlands can be substantial and that primary valuation studies are warranted.      

Valuing the environment as input: review of applications to mangrove-fishery linkages

The following paper reviews recent developments in the methodology for valuing the role of wetlands in supporting economic activity. The main focus will be on mangroves serving as a breeding ground and nursery habitat in support of coastal and marine fisheries. As this particular ecological function of a mangrove system means that it is effectively an unpriced ‘environmental’ input into fisheries, then it is possible to value this contribution through applying the production function approach. The first half of the paper overviews the procedure for valuing the environment as an input, applied to the case of a wetland supporting a fishery. Both the ‘static’ Ellis–Fisher–Freeman approach and the ‘dynamic’ approach developed by Barbier and Strand, incorporating the intertemporal bioeconomic fishing problem, are reviewed. The second half of the paper discusses briefly two recent case studies of mangrove-fishery valuation. An application in South Thailand, which is based on the static Ellis–Fisher–Freeman model, and an application in Campeche, Mexico, which is based on the dynamic approach.     

Sustainability and the value of the ‘regulating’ services: Wetlands and water quality in Lake Victoria

The regulating services provided by ecosystems are amongst the most important for the sustainability of resource use, and yet they are also amongst the least understood. This paper considers one set of regulating mechanisms - the buffering functions of wetlands - and considers the information needed to identify both the value of the services offered by wetlands, and their substitutes. Using data from a catchment discharging water and nutrients to the Kenyan segment of Lake Victoria, the Yala catchment, the paper models the interactions between agriculture and fisheries as mediated by wetlands at the lake margin. More particularly, it estimates the value of the forgone nutrient retention function involved in the conversion of the wetland to agriculture, and the scope for providing the same services through land use change elsewhere in the catchment. The total cost of the payments that would compensate farmers for on-farm nutrient buffering services is 3.86 M US$ year^− 1, or 35% of the total gains from wetland conversion to crop production. This finding contributes to an understanding of both the value of regulating services and how they might most effectively be delivered in alternative ways.     

人工湿地生态系统服务分类及其价值评估——以临沂市武河湿地为例

湿地生态系统为人类的存在和发展提供了大量的必需品和服务。很多国家把发展人工湿地作为净化城市污水的一种途径。文章以临沂市武河湿地为例,根据国内人工湿地的建设目标和湿地生态系统的特点,重新划分人工湿地生态系统服务,建立了评价各个生态系统服务价值的评价方法。评价结果发现,武河湿地不仅实现了净化城市污水、改善当地居民健康、发展湿地旅游等设计目标,还带来了生物多样性增加等生态和社会经济效益。     

A new valuation question: analysis of and insights from interval open-ended data in contingent valuation

This paper introduces a type of open-ended valuation question where respondents state their willingness to pay in the form of an interval rather than a point estimate. Allowing the response to be expressed as an interval has advantages compared to traditional valuation questions: it captures potential valuation uncertainty, facilitates interpretation of uncertainty and most importantly, provides a richer set of information about individuals’ preferences. Furthermore, an open-ended willingness to pay format has advantages if a survey is carried out in more than one country. Too little is known about valuation uncertainty to represent willingness to pay only as an exact value. Therefore, this value should be complemented by upper and lower boundary estimates. In this paper I present new methods for estimating these different values. The methods are illustrated with results from a survey concerning wild salmon in the Vindel River, northern Sweden. The results suggest that the upper and lower boundaries provide a kind of confidence interval for the willingness to pay, which is encouraging for estimating these values to characterise willingness to pay. The results also illustrate that some earlier criticism in the literature of open-ended questions does not apply to the question presented in this paper.     

Deliberative monetary valuation (DMV): Issues in combining economic and political processes to value environmental change

This paper explores and contrasts the different social processes of valuation now appearing as economic means of valuing the environment. Monetary valuation via stated preference approaches has been criticised for assuming well formed and informed preferences and excluding a range of sustainability concerns such as rights, fairness and equity. Deliberative monetary valuation (DMV) in small groups is a novel hybrid of economic and political approaches which raises the prospect of a transformative and moralising experience. Critics of standard contingent valuation approaches have advocated this as offering a way forward. However there has been a lack of clarity as to the means of obtaining values, the expected outcomes and their role. Moving to group settings of deliberation raises concepts of social willingness to pay and accept which are distinct from an aggregate of individual value, although this does not seem to have been widely recognised. A new classification of values is presented appropriate to the literature trying to merge economic and political processes. Values associated with the individual may be exchange values, charitable contributions or fair prices, while social values can be speculative, expressive or arbitrated. The use of DMV is shown to result in different values due to variations in the institutional setting and process of valuation.     

碧塔海湿地生态系统及其保护

碧塔海自然保护区湿地生态系统具有两个显著的特征，即分布海拔高并为森林生态系统所涵养。这种特殊的湿地类型，孕育了特殊的湿地植被和物种，并成为保护区主要的保护对象。根据科学考察结果，碧塔海湿地生态系统可划分为2个植被类型组、4个植被类型、18个群系。本文论及系统特点、系统植被类型，还提出系统的保护值及保护措施。     

The recreational value of coral reefs: A meta-analysis

Coral reefs are highly productive ecosystems that provide a variety of valuable goods and services, including recreational opportunities. The open-access nature and public good characteristics of coral reefs often result in them being undervalued in decision making related to their use and conservation. In response to this, there now exists a substantial economic valuation literature on coral reefs. For the purposes of conducting a meta-analysis of this literature, we collected 166 coral reef valuation studies, 52 of which provided sufficient information for a statistical meta-analysis, yielding 100 separate value observations in total. Focusing on recreational values, we use US$ per visit as the dependent variable in our meta-analysis. The meta-regression results reveal a number of important factors in explaining variation in coral reef recreational values, notably the area of dive sites and the number of visitors. Different valuation methods are shown to produce widely different values, with the contingent valuation method producing significantly lower value estimates. Using a multi-level modelling approach we also control for authorship effects, which proves to be highly significant in explaining variation in value estimates. We assess the prospects for using this analysis for out-of-sample value transfer, and find average transfer errors of 186%. We conclude that there is a need for further high-quality valuation research on coral reefs.     

The validity of the contingent valuation method: Perfect and regular embedding

This article deals with one aspect of the validity claim of the contingent valuation method, namely: to what extent does the method produce different values in situations for which economic theory claims different values. Two aspects of this validity test — perfect and regular embedding — were tested in a field experiment comprising six samples of the Dutch population. Perfect embedding occurs when the value for a specific good is similar to the value for a more inclusive good. Perfect embedding did not manifest itself in the experiment. Respondents considered a package of six goods as well as a package of two goods more valuable than one of these goods. It is argued that this supportive evidence of the method's validity claim occurred because the goods involved were well-defined. Regular embedding occurs when the same good receives a lower value if the value for it is inferred from the value for a more inclusive good rather than if that good is valued on its own. Regular embedding was only found when respondents were given the opportunity to value the inclusive good before valuing the specific good. Respondents who were given information on the inclusive good without valuing it did not state different values than respondents who were not given that information. It seems that respondents perceive an inclusive good as being relevant to their valuation decision only when they are asked to value it. Further research is necessary to shed more light on the underlying processes that may account for this.     

Life-cycle economic model of small treatment wetlands for domestic wastewater disposal

Total system life costs (capital cost and ecological based on released pathogens) were modeled for two-cell domestic treatment wetland systems and compared to costs of traditional and emerging technology systems. Small treatment wetlands that were operationally effective for 20-years had net present value (NPV) costs $500–3000 less than those of sand filter systems. The same treatment wetlands were modeled as releasing ∼4 times pathogens, thus having a much higher ecological cost than sand filter systems. Wetland systems modeled using the highest possible pathogen treatment efficiencies still released ∼2 times the pathogens of sand filter systems. Treatment wetlands must function a minimum of 10 years before replacement in order to remain equivalent in cost to a sand filter lasting 20-years using a 6.25% discount rate. The maximum allowable installation costs for any alternative system (with no annual expenses) were $6675–7700 if required to be equal in total system NPV costs to wetlands. NPV costs were found to be particularly sensitive to uncertainties in installation and maintenance costs. Modeling indicated that the capital savings realized using wetland systems could be used to modify the simple 2-cell design such that both capital and ecological loads delivered to the environment could be minimized. Wetlands may provide a more sustainable option for communities if effluent is centralized and treated in an appropriately scaled wetland system.     

湿地经济价值的研究

湿地是一种有着较高生产力的生态系统，它可以为经济系统提供多种服务，具有重要的经济价值，湿地的经济价值来源于湿地内部生物，物理，化学组分之间的相互作用过程，其价值的大小取决于湿地规模大小，作用性质和该湿地所处的人类社会经济环境。近年来，有关湿地经济价值评估的理论与方法研究已引起了人们的广泛关注，本文系统分析了各类湿地经济价值，探讨了对湿地经济价值进行评估的理论依据。同时概括总结出了对各种湿地服务功能进行评估的方法。     

Economic valuation of environmental services sustained by water flows in the Yaqui River Delta

We attempted to estimate the economic value of environmental services provided by restored instream flows in the water-scarce Yaqui River Delta in Mexico. The Yaqui River begins near the U.S.-Mexico border and continues for 400 km before reaching the Oviachic dam, but has not reached the nearby Gulf of California for decades due to diversions for irrigation. These diversions have degraded the riparian ecosystem, coastal wetlands, and estuaries. Environmental services provided by restored flows in the Yaqui River would include healthy riverside vegetation, wetlands and estuaries, fish and wildlife habitats, non-use values, and recreation. A contingent valuation survey in 40 neighborhoods in the most populated Delta city, Ciudad Obregon, was administered to estimate non-market values of instream uses. Respondents were given a current and hypothetical Delta scenario (the latter assumed restored water flows in the River) and asked a willingness-to-pay (WTP) question regarding purchasing water for environmental flows through higher water bills. Results from 148 in-person interviews indicated that households would pay an average of 73 pesos monthly. WTP was found related to key variables suggested by economic theory and contingent valuation studies elsewhere: income, educational level, number of children in the household, and initial bid amount. These results will allow decision makers to compare the benefits generated by different water uses, including environmental services, and to manage scarce water resources under a long-term sustainable approach.     

Reconsidering Heterogeneity and Aggregation Issues in Environmental Valuation: A Multi-attribute Approach

The economic valuation of complex environmental goods (composed of multiple attributes) is an expanding field of research in ecological and environmental economics. However, several issues are still subjects of debate. This paper focuses on three of them: the linearity of the valuation function in the attributes; aggregation criteria for obtaining social values; and the heterogeneity of individuals’ utility functions. A methodological approach based on Multi-attribute Utility Theory, which enables us to contrast the impact of these concerns on the valuation of environmental goods, is proposed. We employ the methodology to value a protected natural area and, from the results obtained, we can conclude that the non-linearity and the heterogeneity of the individual utility function are relevant aspects of environmental valuation that need to be taken into account when valuing environmental goods.