Persistent effects of pre-Columbian plant domestication on Amazonian forest composition

Abstract

The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples

Rivers shape population genetic structure in Mauritia flexuosa (Arecaceae)

“…Our results are also consistent with the hypothesis suggested that hyperdominant plants in Amazonia, such as M. flexuosa , correlate with their proximity to pre‐Columbian archeological sites, and that plant populations of economically important species are maintained preferentially along river margins (Levis et al., 2017). Furthermore, as humans increasingly hunted large vertebrates in forests typically far from the water (Peres, Emilio, Schietti, Desmoulière, & Levi, 2016), animal‐dependent seed dispersal of M. flexuosa decreased in those areas, resulting in lower gene flow, all the while maintained closer to rivers.…”

“…Furthermore, as humans increasingly hunted large vertebrates in forests typically far from the water (Peres, Emilio, Schietti, Desmoulière, & Levi, 2016), animal‐dependent seed dispersal of M. flexuosa decreased in those areas, resulting in lower gene flow, all the while maintained closer to rivers. Although these observations remain to be tested explicitly, our patterns of high diversity are also consistent with the hypothesis that large population sizes of this species have been maintained by continuous activities of human cultivation, likely for thousands of years (Levis et al., 2017). As a result, outcrossing would be favored by human tending and a high number of reproductive individuals would be maintained, resulting in a higher effective population size and thus higher genetic variation (Frankham, 1996).…”

“…This palm is also used for raw material for construction and for different handicrafts (Santos & Coelho‐Ferreira, 2011) and its fruits, leaves, and seeds are sold widely in markets (Gilmore, Endress, & Horn, 2013). Mauritia flexuosa has been termed a “hyperdominant” species (Steege et al., 2013), in which population densities are five times higher than expected by chance, and that has recently been attributed to human use and tending practices associated to its use (Levis et al., 2017; Rull & Montoya, 2014). …”

The deep human prehistory of global tropical forests and its relevance for modern conservation

“…This is in part a result of limited archaeological survey and exploration of tropical forests relative to other environments. It is also due to the fact that few ecologists and conservationists have engaged with mounting evidence for the long-term human impact of tropical forest environments (however, see 15,31,102 ).…”

“…Accordingly, scholarly assumptions about the timing of significant anthropogenic impacts on tropical forests generally point to the post-industrial era or, at the earliest, the colonial era of European 'discovery' [26][27] . Clearly, the accumulating database of archaeological and palaeoecological evidence for pre-industrial and pre-colonial tropical forest occupation and transformation has not been effectively communicated beyond a restricted set of sub-disciplines (though see [28][29][30][31] ). As a consequence, this evidence has only played a small role in discussions about the start date or characteristics of the Anthropocene (e.g.…”