Biological diversity is crucial to any species, and now there is no reason to think that vegetables are becoming too similar. Two scholars at the University of Georgia report that there has been no overall loss of vegetable diversity in the 20th century, contrary to conventional belief. They compared seed varieties in commercial catalogues from 1903 and 2004 and found that there were only 2.2 percent fewer seed types in the latter catalogue. Explanations for this continued diversity include preservationist efforts to maintain old seed categories, foreign seed imports, and the enthusiastic farmers who developed new varieties of plants.