The development of agriculture in the Americas: An ecological perspective

Agriculture began independently in both North and South America ;10,000 years before present (YBP), within a few thousand years of the arrival of humans in the Americas. This contrasts with the thousands of years that people were present in the old world before agriculture developed. In this paper, I hypothesize that the drastic extinctions of most large herbivores in the Americas may have accelerated the onset of agriculture in the Americas for three reasons: net primary production (NPP) became available for human utilization, the domestication of wild crop types was more feasible in the absence of megaherbivore competition, and hunting societies became more sedentary as their prey went extinct, the first step towards agriculture. I test these theories by calculating NPP liberated following the megafauna extinctions and find that the availability of NPP and the absence of competitive herbivory were significantly correlated with the timing of the onset of agriculture. The extinction of so many keystone herbivores may have accelerated the development of agriculture in the Americas, with humans essentially filling the empty herbivore niches.