THE ENVIRONMENT UPSTREAM
OF OUR SUPERMARKET
While largely hidden, these resources that are called upon to provide our food can be identified and at least vaguely quantified. As Nature's Services -- a book released this week -- points out, many other resources are devilishly hard to measure, much less to place some economic value on. Yet Gretchen C. Daily of Stanford University has recruited a distinguished team of scientists to argue the merits of trying.
Clearly, there will be no agriculture without soil or water. Yet how does one place a dollar value on each inch of rainfall that may disappear regionally with a global warming, or each inch of topsoil lost as the ground dries and erodes with the wind?
Though conservation of many endangered species has been predicated on the immeasurable richness they contribute to an ecosystem, the loss of these species may also bring an unexpected economic toll. If some increasingly rare flower were the sole enticement for bringing certain important pollinators into a region during the spring, for instance, then crop plants that had depended upon that pollinator's visits may suffer when the floral siren goes extinct.
Similarly, though broad-spectrum agricultural chemicals can kill unwanted crop pests, these chemicals often wipe out beneficial insects as well, including honeybees and other pollinators.
Though dollar estimates of the benefits provided by honeybees are tentative and a bit squishy, they now run to between $5.7 billion and $8.3 billion in increased crop yields within the United States, according to bee experts Gary Paul Nabhan and Stephen L. Buchmann, writing in Nature's Services. But their analyses suggest that native (that is non-honey) bees in the United States, which have all but been ignored in any valuation of pollination services, also offer astounding benefits. In the absence of honeybees, they too can pollinate large number of crops. Compared to yields that would have been realized in their absence, native bees could bring gains worth some $4.1 billion to $6.7 billion a year, Nabhan and Buchmann calculate.
Far less easy to quantify are the natural water-cleansing benefits of woodlands and wetlands or the pollution cleanup services provided by healthy soil microbes and plants. Similarly hard to measure is the cost to our fish of toxic industrial pollutants that rain from the sky or long-range transport of pesticides into the soils and water that nourish our foods.
Written by: Janet Raloff of
Science News Online
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