Fatal Harvest: Old and New Dimensions of the Ecological Tragedy of Modern Agriculture

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INDUSTRIAL AGRICULTURE AND BIODIVERSITY

Agriculture implies the simplification of nature's biodiversity and reaches an extreme form in crop monoculture. The end result is the production of an artificial ecosystem requiring constant human intervention. In most cases, this intervention is in the form of agrochemical inputs which, in addition to boosting yields, result in a number of undesirable environmental and social costs (Altieri, 1995).

Global threats to biodiversity should not be foreign to agriculturalists, since agriculture, which covers about 25-30% of the world land area, is perhaps one of the main activities affecting biological diversity. It is estimated that the global extent of cropland increased from around 265 million hectares in 1700 to around 1.5 billion hectares today, predominantly at the expense of forest habitats. Very limited areas remain totally unaffected by agriculture-induced land use changes (McNeely and Scherr 2003).

Clearly, agriculture implies the simplification of the structure of the environment over vast areas, replacing nature's diversity with a small number of cultivated plants and domesticated animals. In fact, the world's agricultural landscapes are planted with only some 12 species of grain crops, 23 vegetable crop species, and about 35 fruit and nut crop species; that is no more than 70 plant species spread over approximately 1,440 million has of presently cultivated land in the world. This is in sharp contrast with the diversity of plant species found within one hectare of a tropical rainforest which typically contains over 100 species of trees. Of the 7,000 crop species used in agriculture, only 120 are important at a national level. An estimated 90% of the world's calorie intake comes from just 30 crops, a small sample of the vast crop diversity available (Jackson and Jackson 2002).

The process of biodiversity simplification associated with industrial agriculture can affect biodiversity in various ways:

* Expansion of agricultural land with loss of natural habitats

* Conversion into homogenous agricultural landscapes with low habitat value for wildlife

* Loss of wild species and beneficial agrobiodiversity as a direct consequence of agrochemical inputs and other practices

* Erosion of valuable genetic resources through increased use of uniform high-yielding varieties

As the industrial model was introduced into the developing world, agricultural diversity has been eroded as monoculture has started to dominate. For example, in Bangladesh the promotion of Green Revolution rice led to a loss of diversity including nearly 7,000 traditional rice varieties and many fish species. Similarly in the Philippines, the introduction of HYV rice displaced more than 300 traditional rice varieties. In the North similar losses in crop diversity is occurring. Eighty-six percent of the 7,000 apple varieties used in the U.S. between 1804 and 1904 are no longer in cultivation; of 2,683 pear varieties, 88% are no longer available. In Europe thousands of varieties of flax and wheat vanished following the take-over by modernvariants (Lipton and Longhurst 1989).

MODERN AGRICULTURE, GENETIC HOMOGENIZATION AND ECOLOGICAL VULNERABILITY

Modern agriculture is shockingly dependent on a handful of varieties for its major crops. For example, in the U.S. two decades ago, 60 to 70% of the total bean acreage was planted with two to three bean varieties, 72% of the potato acreage with four varieties, and 53% with three cotton varieties (National Academy of Sciences, 1972). Researchers have repeatedly warned about the extreme vulnerability associated with this genetic uniformity. Perhaps the most striking example of vulnerability associated with homogenous uniform agriculture was the collapse of Irish potato production in 1845, where the uniform stock of potatoes was highly susceptible to the blight, Phytophthora infestans infestans. …