Does innovation in agriculture harm biodiversity?
By Webmaster, 30 July 2012
The conventional wisdom, as illustrated for millions of readers in the July 2011 issue of National Geographic, holds that the twentieth century was a disaster for crop diversity. In the popular press, this position is so entrenched that it no longer needs a citation. Heald and Chapman conducted a study of all vegetable and apple varieties commercially available in 1903 and compared them with all varieties commercially available in 1981 and 2004. Along the way, they shatter the conventional wisdom and gut the 1983 study that previous scholars have taken as gospel.
By far the most important study of vegetable crop diversity was conducted in 1983 by the Plant Genetic Resources Project of the Rural Advancement Fund, Inc. (RAFI). Although initially unpublished, its findings were widely publicized and influential, as evidenced by the quote above from Pat Mooney and Cary Fowler, who headed the International Conference and Programme on Plant Genetic Resources at the Food and Agriculture Organization of the United Nations. Mooney and Fowler published the RAFI study in its entirety in their classic book, Shattering: Food, Politics, and the Loss of Genetic Diversity.4 The RAFI study compared a comprehensive 1903 United States Department of Agriculture (USDA) inventory of seeds found in commercial seed catalogs with the 1983 holdings in the National Seed Storage Laboratory (NSSL). Mooney and Fowler summarized the study as follows, “RAFI found that approximately 97 percent of the varieties given on the old USDA lists are now extinct. Only 3 percent have survived the last eighty years.” The study was the centerpiece of a recent National Geographic article decrying crop diversity loss, and the 3 percent survival rate is the iconic crop diversity statistic produced in the twentieth century. The data of the research paper by Heald and Chapman reveal that the RAFI study and “lessons” drawn from it suffer from several serious problems. The twentieth century was not, in fact, a disaster for crop diversity. Fowler and Mooney’s original “shattering” three percent figure is the result of a significant math error that is reported for the first time. They correctly listed in their book the raw numbers collected by RAFI, but somehow mis-added or mis-divided the figures. The error is easily seen by recalculating the survival rate from the numbers they provide.