Wetland Ecosystem

1. Introduction

Wetland ecosystem is one of the most productive ecosystems on this planet delivering massive goods and services to human society. However, due to poor awareness of their values and underestimation of their contribution, many wetlands have been converted to farmland or urban areas, or influenced by pollution due to agricultural and industrial activities. Consequentially wetland ecosystems have severely declined and degraded globally during the past decades. In order to restore and protect wetlands, hence ensure a sustainable supply of wetland goods and services, it is important to recognize their values. Vital to this is the development of valuation methods that explicitly link wetland values, the capital base of the ecosystem, to the design of policies (Pearce and Atkinson, 1993; Dasgupta and Mäler, 2000; Arrow et al, 2004; Maler et al, 2008; Dasgupta, 2010).

For a typical wetland ecosystem, its values can be accounted in terms of the populations of its species, fish harvested per day, the amount of carbon stored per year, or the annual number of recreational visits. These are generally categorised as values from wetland production, regulating or cultural services (MA, 2005). Proper and accurate estimation of these values enables comparative analysis of intervention practices and therefore contributes to the improvement of the design of policies (Barbier, 1993; Barbier et al., 1997; Turner et al, 2000). Quality is a critical factor in determining the values of wetlands. A healthy and functioning wetland may provide rich ecosystem services (Zedler and Kercher, 2005; Maltby, 2009).

The quantity of the wetland valuation practice has increased in relatively recent years. In the review by Heimlich et al. (1998), 33...

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...s. Since the values derived with a benefit transfer method are not strictly primary studies, we therefore deleted those items. Subsequently, the values that are not of a single service, but a total economic value (TEV) or marked as ‘various’, had to be moved from the list for consistence. Finally, 70 data items from 27 articles remain in the analysis.

The cross tables based on the data are given in Tables 1 and 2. Table 1 shows the relationship between eco-services and wetland types in terms of the number of study cases, while Table 2 shows the relationship between the services and the methods used for their valuation. The most studied services are food and raw materials which happen mainly at wetlands unspecified by the authors or at floodplains; the most used valuation methods are the direct market pricing method, there are 41 data items out of the total 70.