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General

Description​

Cultural services can be valued based on the stated preference method. This method asks about people's willingness to pay (BTB), in other words what people are willing to give up in monetary terms to obtain nature. People express a willingness to pay for various reasons, both to use nature for recreation, for example, and for its mere existence (non-use value). This value is highly dependent on the characteristics of the area itself, but also on the distance of the area from the place of residence, the amount of nature that someone already has in his or her environment, the income available to the household and other characteristics of the households.

Preferences were enquired for different types of projects and this has led to different functions, each of which can be used separately for a project that best suits it. The functions cannot be combined with each other, but can be added to the results of the provisioning and regulating services.

Background and difference with previous versions of the Nature Value Explorer​

The valuation function (Liekens et al. 2010) described in the first version of this manual still raised many questions when using it, such as:

  • How robust is this feature? How stable are the results over time?
  • How do we deal with the fact that cutting down coniferous forests to plant heathland or deciduous forests in this function has a negative effect on cultural services?
  • Does adding the total cultural value to the results of the regulating services lead to double counting or not?

To address these uncertainties, it was decided to conduct some additional surveys for specific areas.

The results of the additional queries confirm the robustness of the function, but have also led to a number of adjustments in its application.

The stability over time was tested by asking the same people the same survey again a year later. The analysis of the results shows that the parameters have the same order of magnitude and that the willingness to pay falls within the same confidence intervals. We use this to determine a low and high estimate (Schaafsma et al. 2014).

Forest was rated higher than heathland in the first survey in 2009. However, the type of forests was not specified in the survey. In practice, many projects convert coniferous forests into more valuable nature such as native deciduous forests or heathlands. According to the first version of the Nature Value Explorer, there would be no willingness to pay for this change or even a negative effect in the event of conversion to heathland. Various surveys that specifically address the conversion of coniferous forest to deciduous forest or heathland show that there is indeed a positive willingness to pay for the conversion of a coniferous forest of little ecological value to a deciduous forest or heathland. Other conversions of coniferous forests rarely occur in practice. That is why a separate function is included in the manual for this change in land use. The original function is no longer used for this situation.

There was uncertainty about what willingness to pay for new nature actually entails. Are we measuring the total economic value of a land use conversion or just the cultural services? A question was added to the new surveys asking which elements played a role in the choice to provide a value. A quarter of the respondents indicated that they also take the regulating services into account. For some respondents there is therefore an overlap with the other ecosystem services, but we cannot estimate how great this overlap is. Not for the vast majority of respondents. Furthermore, the questions in the survey focused on amenity value and non-use value (an area not being accessible). Therefore, in consultation with various experts, it was decided that the willingness to pay functions are only used to calculate the total value of the cultural services, and not the total economic value.

Finally, surveys were also carried out in 2008 and 2011 specifically for improvements to waterways. An additional valuation function has also been included for this.

Translation to an indicator​

Depending on the type of natural change, the appropriate formula will be applied to calculate the stated value for the study area. As an indicator, we show how much each household that wishes to pay something wishes to pay on average per year.