European missionaries brought more than their religion with them when they populated the U.S. Southwest. They also brought diseases that decimated the local Native American populations.
In general, the arrival of Europeans in the New World was marked by a great decline in Native American populations due to conflict and diseases. However, just how quickly death spread is still questioned by scholars. Some believe death spread rapidly like an all-consuming blaze, while others believe the process was more gradual.
Published in the Proceedings of the National Academy of Sciences, a new study—from researchers from Harvard Univ., Univ. of Arizona, and Southern Methodist Univ.—found that disease outbreak in the U.S. Southwest didn’t occur until nearly a century after Europeans and Native Americans made first contact in the region.
“We found that disease didn’t really start to take effect until after 1620, but we then see a very rapid depopulation from 1620 to 1680,” said Matt Liebmann, of Harvard’s Dept. of Anthropology. “(The death rate) was staggeringly high—about 87% of the Native population died in that short period.”
In the 18 villages the researchers investigated, the population dropped from 6,500 to less than 900 in the 60-year time period. The research area—located in the Jemez Mountains—comprised 100,000 acres of ancestral pueblo villages of the Jemez people.
According to the researchers, daily sustained interaction with the Franciscan priests led to epidemic diseases, violence, and famine.
According to Liebmann, the study also links to the debate regarding whether humans are in a new geological era known as the Anthropocene.
As Native American populations died off, the forest reclaimed the land previously allocated for farming and villages. In turn, this led to more forest fires in the region.
“One of the ‘Early Anthropocene’ theories suggests that because Native Americans were being removed from the landscape on a massive scale, especially in the Amazon, they were no longer burning the forest for agriculture, and as the forest re-grew it sequestered carbon. The argument hinges on the notion that the depopulation of the Americas was so extreme that it left its mark on the atmosphere and climate at global scales,” said Liebmann.
Other researchers have pointed to 1610 as the start date of the Early Anthropocene. Though Liebmann’s research focuses on a later time period, he said the Southwest depopulation could have bolstered the carbon dioxide dip.
The team used LiDAR to map the 18 archaeological sites. Since no excavations occurred, the team relied on dendrochronology to date the sites. The team used the method on trees growing atop the archeological sites to determine when they germinated. Tree growth flourished between 1630 and 1650, the researchers found.
“When we looked at the patterns of fires in the tree rings, we could see that up until about 1620, fires were small and sporadic,” said Liebmann. “Native American fields were acting as literal fire breaks. But as the forest started re-growing, much more widespread fires occurred. That continued until almost exactly 1900, when a combination of increased livestock grazing and a change in federal forest management policies began to suppress all fires.”