The Late Quaternary of the Western Amazon; Climate, Vegetation and Humans
Athens, J. Stephen, Ward, Jerome V., Antiquity
In recent years a great intellectual barricade has been steadily crumbling with respect to our perceptions of the Amazon tropical rain-forest. The notion that the rain-forest was a highly stable ecosystem through the millennia is no longer tenable. Similarly, the view of the rain-forest as a generally unfavourable environment for human foragers and horticulturists is being increasingly questioned. This article adds to a growing body of information fundamentally undermining these notions and the sometimes false anthropological interpretations they have engendered. The data for the Western Amazon region, in fact, show
1 a forest ecosystem highly responsive to climatic change,
2 widespread occupation of the forest very early in the Holocene by horticulturists, and
3 a rain-forest vegetation community that almost certainly has been anthropogenically altered since the early Holocene.
These data, rather than being somehow anomalous for this region, correspond to an emerging pattern of early Holocene horticulture in northwestern South America, extending from the coastal areas to the inter-Andean valleys and into the Western Amazon region. The recent unequivocal demonstration of Palaeoindian occupation in the central Amazon region (Roosevelt et al. 1996) demonstrates the penetration of human populations into the Amazon region at a very early time.
This case concerns preliminary results from a palaeoenvironmental coring project undertaken in 1994 in the Western Amazon region of Ecuador (roughly between 0[degrees]27[minutes]S, 76[degrees]37[minutes]W to 0[degrees]53[minutes]S, 76[degrees]11[minutes]W). The specific location is an interfluvial (between major river systems) zone along a 126-km petroleum pipeline access road extending in a southeasterly direction from the Rio Napo near Limoncocha [ILLUSTRATION FOR FIGURE 1 & 2 OMITTED]. The transect crosses the Indillana, Tiputini, Tivacuno, Yasuni and Bahameno rivers. Averaging 220 m above sea level (asl) and over 3300 mm of annual rainfall, this location is characterized by an evergreen tropical rain-forest. It is the sparsely populated homeland of seminomadic hunter-horticulturist Waorani Indians (Broennimann 1981; Kaplan et al. 1984). Five cores were obtained from dispersed wetlands along the access road. The investigations were conducted under the aegis of the Fundacion Alexander Von Humboldt of Quito on behalf of the Maxus petroleum company.
The sediment coring project was designed to investigate a series of interrelated questions concerning human occupation and the palaeoenvironment in the study area. It was expected that this approach would be helpful in providing data concerning possible Holocene climate change and its relation to the character of the natural environment through time. Other research issues related to acquiring information concerning possible regional and local geomorphological changes, the date for the initial appearance of anthropogenic markers in the sedimentary record, the nature and timing of possible human impacts to the rain-forest and, finally, aspects of human subsistence. Of immediate interest was that such investigations be complementary to archaeological studies conducted concurrently by the Fundacion Alexander Von Humboldt in the same area (see Netherly 1997).
The fundamental assumption for most palaeoenvironmental coring investigations is that wetland sedimentary basins or lakes can often provide lengthy and uninterrupted records of geologically recent sedimentary deposition (see Binford et al. 1987: 116-17). Microfossils and occasionally macrobotanical remains in the sediments, which are derived from the surrounding watershed, are usually well preserved because of anoxic conditions. Environmental change can be often readily distinguished through changes in pollen, phytolith and particulate charcoal frequencies, and sedimentary and chemical changes may also provide important clues to past environmental conditions. …