The Native American Depopulation From European Disease had Significant Ecological Impacts

There is little dispute that in the wake of European colonists' arrival in the New World, Native American populations were decimated by disease and conflict. But when it comes to the timing, magnitude, and effects of this depopulation -- it depends on who you ask.

Many scholars claim that disease struck the native population shortly after their first contact with Europeans, and spread with such ferocity that it left tell-tale fingerprints on the global climate. Others, however, argue that -- though still devastating -- the process was far more gradual, and took place over many years.

A new Harvard study, however, suggests both theories are wrong.

Led by Matt Liebmann, the John and Ruth Hazel Associate Professor of the Social Sciences in the Department of Anthropology, a team of researchers was able to show that, in what is now northern New Mexico, disease didn't break out until nearly a century after the first European contact with Native Americans, coinciding with the establishment of mission churches.

But when it did finally strike, the study shows, the effects of disease were devastating. In just 60 years, native populations dropped from approximately 6,500 to fewer than 900 among the 18 villages they investigated. The study is described in a Jan. 25, 2016 paper published in the Proceedings of the National Academy of Sciences.

In addition to Liebmann, the study was co-authored by Joshua Farella and Thomas Swetnam from the University of Arizona and Christopher Roos from Southern Methodist University.

"In the Southwest, first contact between native people and Europeans occurred in 1539," Liebmann said. "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. (The death rate) was staggeringly high -- about 87 percent of the Native population died in that short period.

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