Pre-Columbian Floristic Legacies in Modern Homegardens of Central Amazonia

Historical ecologists have demonstrated legacy effects in apparently wild landscapes in Europe, North America, Mesoamerica, Amazonia, Africa and Oceania. People live and farm in archaeological sites today in many parts of the world, but nobody has looked for the legacies of past human occupations in the most dynamic areas in these sites: homegardens. Here we show that the useful flora of modern homegardens is partially a legacy of pre-Columbian occupations in Central Amazonia: the more complex the archaeological context, the more variable the floristic composition of useful native plants in homegardens cultivated there today. Species diversity was 10% higher in homegardens situated in multi-occupational archaeological contexts compared with homegardens situated in single-occupational ones. Species heterogeneity (β-diversity) among archaeological contexts was similar for the whole set of species, but markedly different when only native Amazonian species were included, suggesting the influence of pre-conquest indigenous occupations on current homegarden species composition. Our findings show that the legacy of pre-Columbian occupations is visible in the most dynamic of all agroecosystems, adding another dimension to the human footprint in the Amazonian landscape.历史生态学家已在欧洲、北美、中美洲、亚马孙地区、非洲及大洋洲的表观野生景观中证实了遗留效应。如今全球多地的考古遗址仍有人类居住与耕作，但此前尚无研究关注这些遗址中最具动态性的区域——家庭菜园（homegardens）内的史前人类活动遗留效应。本研究证实，现代家庭菜园的有用植物区系，部分源自亚马孙中部地区的前哥伦布时期人类活动遗留：考古背景越复杂，当前当地耕作的家庭菜园中本土有用植物的区系组成变异性越高。相较于单一活动考古背景下的家庭菜园，多活动考古背景中的家庭菜园物种多样性高出10%。所有物种的考古背景间物种异质性（β多样性，β-diversity）整体相似，但仅纳入亚马孙本土物种时，该异质性则呈现显著差异，表明征服前的原住民活动对当前家庭菜园的物种组成存在影响。本研究结果表明，前哥伦布时期人类活动的遗留效应，在所有农业生态系统中最具动态性的家庭菜园中依然可见，为亚马孙景观中的人类足迹增添了新的研究维度。