ENHS Nature Trails Nov. 97 Article 3

Ecological Collapse, A New View of the Spanish Conquest of Mexico
by Reida Kimmel
a review of "Prophecy, Plague and Plunder" by Joel Simon, Amicus Journal, Spring 1997

In 1519 when Hernan Cortes, his small army, and sixteen horses landed at Veracruz to commence their conquest of Mexico they found a land in ecological balance; a land of gardeners who had no domestic livestock. The Aztecs and their subject peoples had managed and regulated their environment carefully. Theirs was a tended landscape of gardens, fields and canals. The conquerors brought doom, first to the people of Mexico and then to their land. This is how it happened.

Cortes' force was joined in 1520 by an African slave with smallpox. He recovered but carried the disease with him to the Aztec capital city, Tenochtitlan. Cortes first entered the city in 1520 and deceitfully captured Emperor Moctezuma but then was forced to withdraw following an Aztec uprising. The smallpox did not retreat, however, and within a few months at least half the population of the city was dead. From December, 1520, until August, 1521, Cortes besieged Tenochtitlan. When the city fell, his forces found a city of corpses. Measles and chickenpox followed the smallpox in destroying the people of the Valley of Mexico. Many individual towns lost 90% of their population. How many lives were lost throughout what is now the Mexico nation is unknown, but their carefully terraced gardens were abandoned. The soil washed away in the rain.

The next great plague the Spanish brought was domestic livestock. In the first decade of conquest the Spanish brought pigs to feed the troops. The pigs escaped to become feral, living mostly along riverbanks and in the woods. They spread far and wide. Arkansas razorback pigs trace their origins to feral Spanish pigs.

Mexico's plains had not been grazed since the end of the Pleistocene. Now Spanish cattle spread north from the Valley of Mexico, growing so plentiful that only twenty years after the conquest even the Indian villages were well supplied with beef. Some herds were as large as 20,000 animals. Despite efforts to control their grazing, the cattle trampled the Indians' farms and fouled the water. Soon Mexico's central highlands felt the effects of overgrazing: erosion, gullying, soil turning to hardpan and lost forever to cultivation. The soil could not absorb rainfall. Pine and oak forests and native grasslands were replaced by thorn scrub, mesquite, maguey and yucca. Sheep came to Mexico in the 1530s and '40s. Their effects were even more devastating to the land. By the late 1550s there were 400,00 of them; by 1570 that number had increased to two million. Sheep grazed the land closer than cattle did. They and their companion goats ate young trees. Deforestation accelerated as the Spanish developed mines. Trees were essential for building mine shafts and for providing the charcoal for smelters. In Yucatan, forests were felled to plant sugarcane. Wood was the fuel needed to process cane juice into sugar. Cattle and sheep grazed the former forest lands. The trees did not return.

By the 1570s and 1580s the population boom ended for cattle and sheep. They had destroyed the riches of the wild lands. Live stock numbers dwindled until they came into balance with what the now impoverished land could support. But the herds of feral cattle and horses continued to move north into what is now Texas. Spanish settlers brought their domestic animals north as they moved into California and New Mexico. There is a herd of feral horses in Utah today which traces back directly to horses used by eighteenth century Californians.

Many historians believe that ultimately history is not about what famous men and their armies did but rather it is about how societies impact the earth. It is the choices which we make today which create the conditions that shape future events. The Spanish saw the Aztecs and their way of live as vile because they sacrificed and ate human beings. They saw their own European-style livestock centered economy as the good norm because it had worked for them, more or less, for centuries. Perhaps they never saw--certainly they never understood--the profound harm that their transplanted society had done to the New World.

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