ples inhabited the Quijos Valley on the eastern Andean flank of northern ... Nicholas J. D. Loughlin 1,2*, William D. Gosling 1,2, Patricia Mothes3 and Encarni Montoya1,4 ..... eastern cordillera of Ecuador: petrography, chemistry, tephra and glacial .... Please select the best fit for your research. .... Specimen deposition.
Articles https://doi.org/10.1038/s41559-018-0602-7
Ecological consequences of post-Columbian indigenous depopulation in the Andean–Amazonian corridor Nicholas J. D. Loughlin 1,2*, William D. Gosling 1,2, Patricia Mothes3 and Encarni Montoya1,4 European colonization of South America instigated a continental-scale depopulation of its indigenous peoples. The impact of depopulation on the tropical forests of South America varied across the continent. Furthermore, the role that indigenous peoples played in transforming the biodiverse tropical forests of the Andean–Amazonian corridor before ad 1492 remains unknown. Here, we reconstruct the past 1,000 years of changing human impact on the cloud forest of Ecuador at a key trade route, which connected the Inkan Empire to the peoples of Amazonia. We compare this historical landscape with the pre-human arrival (around 44,000–42,000 years ago) and modern environments. We demonstrate that intensive land-use within the cloud forest before European arrival deforested the landscape to a greater extent than modern (post-ad 1950) cattle farming. Intensive indigenous land-use ended abruptly around ad 1588 following a catastrophic population decline. Forest succession then took around 130 years to establish a structurally intact forest—one comparable to that which occurred before the arrival of the first humans to the continent. We show that nineteenth-century descriptions of the Andean–Amazonian corridor as a pristine wilderness record a shifted ecological baseline—one that less than 250 years earlier had consisted of a heavily managed and cultivated landscape.
T
he cultural collision that followed the arrival of Europeans to the Americas in ad 1492 (all dates hereafter in years ad) triggered conflict and disease, and enforced labour that resulted in the deaths of an estimated 80 million indigenous people1. Uncertainty remains over the ecological consequences that followed this depopulation and the influence that indigenous peoples exerted on the landscape before European arrival2,3. In South America, historical and ecological evidence points to disparities in the timing, spatial distribution and magnitude of tropical forest modification by pre- and post-European contact peoples4–11. Here, we examine how the tropical montane cloud forests of the eastern Andes (2,000– 2,900 m above sea level)—today one of the most biodiverse, carbonrich and threatened habitats on Earth12—were transformed over the past 1,000 years of changing human impact. Before European arrival in the Americas, indigenous peoples inhabited the Quijos Valley on the eastern Andean flank of northern Ecuador13–15 (Fig. 1). Evidence from archaeological16,17, anthropological13,14 and historical records18 indicates that this Andean–Amazonian corridor formed the eastern frontier of the Inkan Empire (1400–1532)14,19. The Inkas undertook expeditions into the Quijos region during their expansion, subjugating the native population; however, they established no infrastructure or permanent presence14,19. The peoples of the Quijos Valley remained a distinct group that facilitated exchange between the Inkas and the peoples of the Amazon13,15. Following European arrival, Gonzalo Díaz de Pineda (1538) and Gonzalo Pizarro (1541) led the first excursions by Spanish conquistadors into the Ecuadorian Amazon14. Leaving from the capital city of Quito, they travelled east over the Andes, through the Quijos Valley and into the Amazonian lowlands in search of gold and cinnamon13,14. By 1559, the Spanish town of Baeza had been founded in the Quijos Valley, near the indigenous
settlement of Hatunquijos (Fig. 1). Contemporary Spanish accounts indicate that, at contact, the indigenous population dispersed throughout the wider Quijos region numbered around 35,000, and that by 1577 a population of around 11,400 indigenous people were concentrated around the town of Baeza14. However, brutal treatment of the indigenous peoples, disease, the establishment of ‘encomienda’ (forced labour and tribute)20 and numerous indigenous uprisings (1560–1578)13 led to a 75% decline in the native population by 160014. Depopulation continued and the region was virtually abandoned for the next 250 years, so that by the middle of the nineteenth century the former town of Baeza consisted solely of 3 small huts21,22.
Results
Lake Huila (00° 25.39′ S, 78° 01.06′ W; 2,608 m above sea level) is 30 m in diameter and located on an isolated lava terrace within the Quijos Valley, underlain by volcanic rocks derived from the nearby Antisana Volcano23 (Fig. 1 and Supplementary Figs. 1 and 2). A mosaic of open cattle pastures and secondary forest fragments occupy the valley floor along the Río Quijos, a tributary of the Río Coca and Río Napo (Fig. 1). Montane cloud forest scarred by landslides and deforestation cover the steeper slopes of the valley. In 2013, two parallel sediment cores of 209 cm were recovered from the centre of Huila using a Livingstone piston corer24. A multiproxy palaeoecological approach was used to reconstruct past environmental change from the top 50 cm of the core (Fig. 2 and Supplementary Fig. 3), representing approximately the past 700 years (Supplementary Fig. 4). Pollen analysis provided evidence of past local (100 microns) to indicate local fire and micro-charcoal (
