On the why and how of biodiversity valuation

At the 2002 Johannesburg World Summit on Sustainable Development, representatives of 190 countries committed to “ significantly reduce the current rate of biodiversity loss at the global, regional, and national level…”

However, 2010 came and went and in spite global actions, biodiversity continued to decline at an alarming rate. In their two-yearly report released on October 27 2016, the Global Footprint Network, WWF and the Zoological Society of London warn that “global wildlife populations could drop two-thirds by 2020…” And this is not in 20 years, this is 3 years from now.

Even though biodiversity does not have a monetary value, it does have an intrinsic value. Most of us realize the exceptional value of biodiversity without knowing how much it is actually worth in euros. However, without these numbers, it is impossible to assess what the monetary benefits are of preserving a certain habitat, or taking measures to reduce harmful substances from entering our natural world. The only thing that is known is how much these policy measures will cost and which economic sectors they will hurt financially. Therefore, we are in need of a scientifically-based methodological framework that captures the value of biodiversity in such a way that policy makers can justify environmental decision making by being able to represent not only the costs but also the monetary benefits of biodiversity preservation or ecological restoration.

Expressing the value of biodiversity in monetary terms is not new. However, the way we value biodiversity needs urgent revising. Up till now, the majority of biodiversity valuation studies asked respondents what they were “Willing To Pay” for a certain landscape or the opportunity to see a particular species in the wild. This approach favors highly charismatic species such as whales and panda bears for example. But what would happen if respondents were asked how much they were willing to pay for bugs, or insects or beetles? Many of the respondents might even pay to get rid of them.

It is for this reason that we are contributing to devising a new methodology, a methodology that does not distinguish between ‘beautiful’ or ‘ugly’ animals, but a methodology that values biodiversity based on the important roles it performs in the ecosystem such as bees providing pollination services for more than 80% of the world’s crops, many insects providing pest control services thereby protecting crops from harmful pests, aquatic macro-invertebrates controlling mosquito populations… The list goes on and on. Bottom-line is that all these ecosystem services provided to us free of charge are delivered by healthy ecosystems consisting of many interacting species, each performing unique ecological functions, with some directly but all definitely indirectly beneficial for humans.

Our novel methodological framework for the monetary valuation of biodiversity is based on the ecological function of the species in the ecosystem. In a case study we valued the presence of three natural predators for pear production in Flanders. The three natural predators under investigation control pear psylla, which is responsible for introducing a black mold on the pear skin. These ‘black pears’ are of a lower quality and therefore considerably reduce the farmer’s income when brought to the market.

The framework sets out by simulating the effect of the presence of different natural predators on the pest insect. For this purpose, an ecological model is built with dynamic simulation software (Stella 10 1.0.1) available from ISEE systems. Systematically, a species is removed from the system and the effects on the population of pest insects are registered. Upon removing all three natural predators, biological pest control reduces with 13%, which has catastrophic effects on the population of the pest insect. Pear psylla has many generations per year and a slight increase in the population in the beginning of the year has exponential effects for the coming generations that year.

In a second step it is assessed what the impact is of an increase in pest insects on the amount of black pears produced. So when biodiversity decreases (in this case the number of natural predators), pest insect numbers increase, crop yields or food quality decreases and the farmer’s income reduces. This reduction in income can be attributed to the fact that we have lost biodiversity and therefore constitutes the indirect use value of the presence of biodiversity.

In our example, results indicated that the loss of three predators could decrease net farm income with 88.86 € per hectare to 2186.5 € per hectare. For the pear production sector in Flanders in 2011, this constitutes to an indirect use value of 0,68 million € for one predator and 16.63 million € for the presence of three predators.

Our novel methodological framework values biodiversity based on the ecological function of species, through the delivery of comparable monetary standards. As such, it provides an additional justification for the argument for biodiversity conservation by not only stressing the costs but also the monetary benefits of biodiversity conservation.


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