A paper in the latest Journal of Applied Ecology demonstrates that biodiversityÂ provides valuable ecosystem services — though, pace the previous post, it deals with just one of these services. Swiss researchers looked at the effect of “ecological compensation areas” (ECA), meadows managed in such a way as to maintain high levels of biodiversity, on nearby fields which were managed more intensively. In particular, they focused on the effect on pollinators. They concluded that pollinators will be more diverse and effectiveÂ in intensively managed farmlandÂ — thus providing a better service — when there is a botanically diverse ECA close by.
A study published in tomorrow’s Nature (news item) suggests that previous estimates of the value of biodiversity in supplying ecosystem services may have consistently underestimated its importance. This is because previous efforts looked at single services, such as clean water or pollination. Professor Andy Hector from the University of Zurich, Switzerland and Dr Robert Bagchi from the University of Oxford developed a new method to look at multiple ecosystem processes in the same analysis. According to Professor Hector “previous analyses have been too narrowly focused … and have effectively assumed that the species that are important for one ecosystem service can provide all the other services too â€“ but that doesnâ€™t seem to be the case”.
Applying their method to data from European grasslands, Hector and Bagchi found that higher levels of biodiversity were required when all seven of the measured ecosystem services were taken into account than when focusing on any single ecosystem service in isolation. Moreover, different ecosystem services were affected by different groups of species. Dr Bagchi explained that “because different species influence different ecosystem services more species are required for a fully-functioning ecosystem than for one managed with a single goal in mind”.
What’s really neat is that the researchers are now testing their ideas in the tropics. Professor Hector is one of the lead researchers on the Sabah Biodiversity Experiment in Malaysian Borneo, which investigates whether tree-replanting schemes are more successful in restoring fully-functioning forest ecosystems when they use a high diversity of species than the monocultures that are usually planted. That’ll be one to watch.
Readers of this blog probably share my belief that agricultural biodiversity (ABD) is critical to our future. Economists have come up with elaborate concepts and numbers to value it. Scare scenarios abound, about the potential failure of genetically narrow crops jeopardizing the world’s food supply. (Luckily they haven’t materialized, for the most part). Yet most people seem to be thoroughly indifferent to ABD, to judge from the general unawareness and the uniformity of our consumption, through which every single day we decide against ABD. I have therefore always believed that unless we can connect people emotionally and positively to the cause of agricultural biodiversity, its conservation and use will be a difficult sell.
One of the pillars of my belief has long been Chanel 5 perfume.
Isn’t it derived from the Chanel 5 tree, also called ylang ylang? Botanically known as Cananga odorata, ylang ylang is a widely cultivated tree with heavily fragrant flowers, originally from Asia. Those flowers have ensured its spread around the tropics. Here in Cali, Colombia, where I live, the tree is common, and releases its sweet scent to perfume the balmy tropical nights. What better example could there be that agricultural biodiversity not only ensures our survival, but adds glamour and excitement to our lives?
That pillar received a devastating blow when a well-meaning colleague recently pointed out to me that Chanel 5 is a blend of entirely synthetic aldehydes, and has been since its launch in 1921. It actually epitomizes the industry’s break from a natural to a synthetic perfume model. I should have investigated more thoroughly. Indeed, I have since learned that perfumes nowadays are overwhelmingly made from synthetic sources and not at all as natural as you might conclude from the vocabulary experts use to describe fragrances.
However, I must come to the defense of the industry. Internet marketers of Chanel 5 do not hide the importance of aldehydes in the Chanel 5 fragrance. The nomenclatural equation of perfume and tree, as far as I can see, is mostly to blame on websites such as this, which seem unfaithfully to copy one another. (There is an excellent monograph on Cananga odorata — and loads of other species — at Agroforestry.net, but it too erroneously states that the flowers are the basis for Chanel 5 perfume.)
Which leaves me puzzling: how did the tree get its name? Was it simply because its smell happens to resemble the perfume? Or was Coco Chanel inspired by the tree’s fragrance, and then realized that it was cheaper and more reliable to base its production on synthetic chemistry? I am also worried: Are consumers sophisticated enough to appreciate the greater complexity of natural fragrances? If so, they might start once again to demand perfumes made of natural ingredients (as they had to in the past, before synthetics changed the industry), thus providing income opportunities to poor tropical producers?
Anyone out there to educate me on this?
Organic farming again today. Iâ€™ve come across two papers from opposite ends of the world on this subject which it may be worth discussing together.
The first, from New Zealand, describes an experimental attempt to put a value on the ecosystem services provided by different pieces of arable land near Canterbury. Thatâ€™s interesting â€“ and difficult â€“ enough, but the authors did this for both conventional farms and neighbouring organic farms. Values for the following services were calculated: biological control of pests, soil formation, mineralization of plant nutrients, pollination, services provided by shelterbelts and hedges, hydrological flow, aesthetics, food, raw materials (fibre, fuelwood, pharmaceuticals etc.), carbon accumulation, nitrogen fixation and soil fertility.
The results were that organic fields provided ecosystem services to the tune of US$ 4,600 per hectare per year, compared to US$ 3,680 for conventional fields: â€œthere were significant differences between organic and conventional fields for the economic value of some ecosystem services.â€ Now, that must be associated with increased (agro)-biodiversity in the organic fields â€“ more natural enemies, more pollinators, more earthworms, more medicinal plants etc. â€“ but this was not measured in the study.
The other paper did compare diversity in organic and conventional farms, but only for plant at the species level, and no attempt was made to calculate values. Working in the south of England, the authors found significantly more plant diversity in organic arable fields as compared to conventional fields â€“ though no differences in the plant diversity of other types of habitats within farms, such as woodland fragments and hedgerows.
I suppose what we need is a combination of these approaches, bringing together diversity assessment with valuation. Because in the end weâ€™re only going to be able to conserve biodiversity if we can adequately value it.