How much is a weasel worth , or a sunflower field ?

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cout valeur de la nature mettre un prix sur la biodiversité

To give a value to biodiversity is a difficult exercice. Bernard Chevassus-au-Louis, former chairman of the National Museum of Natural History, former Inra Director, has chaired a working group and developed a method to calculate the economic value of Biodiversity. He explains his work.

Can we stick a label on the back of an animal or a plant and give it a certain value ?

No. It’s impossible to give an economic value to a species as such, due to the huge complexity of existing ecosystems . In a soil, for example, you find bacteria, mushrooms, worms, insects, tree roots, moss, which all together interact and all together constitute the soil.In our method, we consider all this as a big black box. To approach the various elements of the ecosystem one by one would be as ridiculous as assessing the value of an orchestra by listening in turn to the first violin, then the second, then the bass-drum and the horn …

So, how much is the value of a weasel or a salmon ? I dont know. The value of a species depends on many factors : geographical unit, knowledge of its functions ,time element, but also depends on our point of view which obviously is anthropocentered …

You have assessed the ecosystems using the notion of ‘services rendered’, in other words, their usefullness. Why did you limit yourselves to this aspect ?

Because we are lazy !! No, seriously ,it’s because it is the most simple solution. Nature must be approached from the angle of the services it provides. Any pains for doing something deserves a reward, subject of course to the reward being assessed correctly.We also assumed that there is proportionality between the quantity of biodiversity and the quantity of services rendered, which was the most simplest and basic assumption.To my knowledge, there is no better model.

We used the typology outlined in the Millenium Assessment Report. It lists a number of services, such as the provisionning services ( timber, food …)the regulating services ( climate, deseases, water … ) and the cultural services ( beauty, inspiration, ecotourism …)

But are they services which cannot be assessed ?

Biodiversity has obviously an impact on health , but due to lack of sufficient data, we were unable to assess it. The same also applies to the very important role biodiversity plays in the fight against erosion ; there again, insufficient data.

Let’s imagine a forest in Normandy : it plays its role of buffer by absorbing the rainwater in this particularly humid region. Simply by being there , it prevents dramatic mud slides. Ideally we should also take into account not only the cost of compensating the inhabitants who may lose their houses, the purchase of light soil to replace what has been washed away etc….

Added to that, some services today are not yet known but might be tomorrow. Primary forests are certainly a plentiful reservoir of plants or animals with a pharmaceutical value but we don’t know them yet.

Furthermore we concerned ourselves solely to what is called the usage value. For example, the whale which lives off the patagonian waters might have a moral value for a swedish family who will never see it, but we did not take it into account . We believe that there are values other than economic : heritage, culture ,aesthetic,ethics, which cannot be expressed in money terms.

You have also introduced a distinction between remarkable and ordinary biodiversity. Why,

The remarkable biodiversity is the one which figures in the protection lists, biotope regulations ; habitat directives, classified sites etc We tackle biodiversity according its various levels of organisation : Genetic, specific or ecological.

They are pandas, whales,amazonian forest, some mangroves, a local species of domestic pigs with original features. It is similar to our historical monuments. Nobody would think seriously of giving a value to Notre-Dame. Furthermore these elements of our heritage are often scarce, because a threatened species loses its viable population. Consequently, and it is almost paradoxical, this species provides almost no service, either to the ecosystem or the economy at large.

And of course, this remarkable biodiversity must first and foremost be noticed.. It is completely conditioned by the present state of our knowledge.

In giving a value to nature , are we not encouraging its use as a commodity ?

For a very long time we wondered wether with this approach we were not getting involved in a deadly spiral. And yet, from a legal point of view, when a river is polluted by a company, everybody finds it normal for that company to pay damages…..This is why we believe that giving a monetary value to nature, does not make it a mercantile commodity.

But of course, what we need now is a clear-cut legislative framework

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