Environmental and Social Change in the Valle del Mezquital, Mexico, 1521–1600

The often disastrous consequences of the introduction of exotic animals into a New World environment are very clearly demonstrated by the sixteenth-century history of the Valle del Mezquital, Mexico. A rapid and profound process of environmental degradation, caused by overstocking and indiscriminate grazing of sheep in the post-conquest era, leads us to ask whether the Spanish always acted in their own long-term interests in the New World.