Biodiversity Studies: What price wild things?

Andy Ho, Straits Times 17 Apr 08;

IN THE environmentalist classic A Sand County Almanac, its author Aldo Leopold declared: 'There are some who can live without wild things, and some who cannot.'

Actually, because the webs of life are so intimately woven together, none of us can live without the wild things. Take just insects and microbes that break down organic matter. If they stopped working, we would soon be up to our necks in waste.

When Europeans took their non-indigenous cows Down Under in the 1780s, cow dung patties quickly came to pose a problem in the landscape. While the native dung beetle gobbled up the kangaroo's dry pellet droppings quickly, it was not adapted to tackle the big, moist cow patties. Besides fouling pastures, the patties were also breeding ground for the buffalo fly inadvertently introduced with the cattle. Hence, the patties had to be buried.

In 1968, African cattle dung beetles were imported to deal with this problem. One variety, the ball roller, detaches small bits of dung and rolls them away to be buried. Another variety, the tunneller, burrows into the soil and fills its tunnels with dung balls. In this way, they remove the patties efficiently.

The beetle activity also reduces water contamination, increases air and water infiltration into the soil and returns nutrients to the earth. And it can reduce flies breeding in dung by 80 per cent.

Converting land for farming and husbandry, forestry, mineral or fossil fuel extraction as well as urbanisation are now recognised as the main forces degrading the environment, destroying ecosystems in the process and causing losses in biodiversity.

That biodiversity matters was made abundantly clear during the Irish Potato Famine. Because of overpopulation, people moved to less fertile areas to farm, where only the potato - originally from the Andes mountains - could grow. By 1800, 90 per cent of the Irish population was dependent on the potato for food.

Since only a single variety was grown, when the late blight fungus struck in the 1840s, Ireland's entire potato crop was decimated. From 1845 to 1947, a million people died of starvation and two million emigrated to Europe and America.

The economic and human costs of biodiversity losses are usually less dramatic than this if only because this sorry episode in history has taught many about the dangers of monoculture. According to Lord Nicholas Stern, who spoke at the Civil Service College last week, the British government has a report in the works on the economic impact of biodiversity declines around the world.

Many economists had found much to agree and disagree with his 2006 Stern Report on the economic impact of global climate change. It is also likely that the upcoming biodiversity report will evoke as much controversy worldwide. One area of contention will likely pivot on the models of biodiversity that these British economists will rely upon to price biodiversity.

Up to now, most such economic studies tended to, for simplicity's sake, rely on counting discrete species to see if the numbers are rising or falling. But counting species may not be the best way to measure the impact of biodiversity change because how species interact with one another - and their interactions with their environments - also matter. Ecologists now say these interactions and interdependencies may matter more than raw species numbers.

If counting species is not the best way to model the significance of biodiversity change, putting a price tag based on whether species are becoming more abundant or less may not be the most accurate way of going about things. However, being the most convenient way, most economic studies of biodiversity resort to it by default.

For example, a 2007 econometric study done for Resources for the Future, a well-known Washington-based environmental NGO, roped in the expertise of paleo-ecologists to look for pollen remains in peat in Scotland. These were carbon-dated to the 1600-2000 period.

The study aimed to show that the more intensive the land use was, the greater was the biodiversity decline. Though the numbers of livestock would be a good proxy for intensity of land use, only post-1860 data was available. Even then, the early data was patchy.

So, instead, the study's authors assumed that higher meat and wool prices would get farmers to raise more livestock. Thus meat and wool prices as proxies for land use intensity were tracked against plant species diversity, measured as the number of plant species per period as detected in the pollen remains.

The researchers concluded that more intensive grazing led to greater declines in biodiversity. But this would be a valid conclusion only if counting pollen species measured adequately the significance of changes in biodiversity. The researchers acknowledged that biodiversity includes not just species abundance but also 'the interactions between them, and the natural systems that support them'. Yet the last two items were not priced because of technical difficulties.

Indeed, most economic studies of biodiversity tend to resort to this bits-and-pieces approach and focus on taking an inventory of discrete species. A more holistic modelling would include the interaction processes too. However, such processes are continually changing in unpredictable ways that ecologists cannot yet identify comprehensively - especially in complex ecosystems like tropical forests. If so, ecologists do not know for sure at what point biodiversity decline will matter. Thus, pricing such changes would involve many orders of guesswork.

It would be most interesting to see how the British economists deal with these uncertainties in their pricing models. But this difficult work needs to be done if parties to the Convention on Biological Diversity - which Singapore ratified in 1995 - are to begin working towards their target of conserving at least 10 per cent of each of the world's ecological regions by 2010.

Pricing biodiversity accurately and fairly may enable the signatories to begin acting in concert. And they should too. After all, none of us can live without the wild things.