Erickson 2010

Diversity 2010, 2, 618-652; doi:10.3390/d2040619
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diversity
ISSN 1424-2818 www.mdpi.com/journal/diversity Article

The Transformation of Environment into Landscape: The Historical Ecology of Monumental Earthwork Construction in the Bolivian Amazon
Clark L. Erickson Department of Anthropology, University of Pennsylvania, 33rd and Spruce Streets, Philadelphia, PA 19104-6398, USA;E-Mail: cerickso@sas.upenn.edu; Tel.: 215-989-2282; Fax: 215-898-7462. Received: 28 January 2010; in revised form: 14 April 2010 / Accepted: 15 April 2010 / Published: 19 April 2010

Abstract: Although the Neotropics are recognized as a region rich in biological diversity, the origin, evolution, and maintenance of this phenomenon continues to be debated. Historical ecologists and landscapearchaeologists point out that the Neotropics have a long, complex human history that may have been a key factor in the creation, shaping, and management of present day biodiversity. The construction of monumental earthworks referred to as ring ditches of the Bolivian Amazon and surrounding regions in late prehistory had considerable impact on the fauna, flora, soils, and topography of forest islands.Patterned landscape features, historical documents, energetics, and historical ecology are used to understand the transformation of forest islands into anthropogenic built environments. Keywords: historical ecology; landscape archaeology; historical contingency; engineered landscape; forest islands; Bolivia; Amazonia

1. Introduction In a recent article, Leigh and colleagues ask, “Why do sometropical forests have so many species of trees?” [1]. The answer is critical to understanding how to protect and manage the remaining biological diversity, and in some cases, to restore that diversity, in the vast tropical regions of Earth. The authors breakdown the complex issue into a series of questions and propose that tree “species that are now common must have spread more quickly than chanceallows,” assuming that new species

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probably begin as small populations, and thus, certain niche opportunities promote the increase of these originally rare species [2]. Agreeing with previous scholars who emphasize long-term environmental stability and a warm and relatively low seasonality, Leigh and colleagues conclude, “… neither disturbance nor microhabitatspecialization can explain the diversity of tropical trees, even though larger-scale habitat and climate differences are the primary causes of species turnover. Increased activity of specialized pests and pathogens in less seasonal climates appears to be a primary cause of the latitudinal gradient in tree diversity” [3]. In reaching their conclusions, the authors ignore the long and complex humanhistory of tropical forest environments extending back into the late Pleistocene. What possible role could human activities have played in providing the “niche opportunity” for originally rare species and the spread, distribution, and maintenance of individual tree species, α-diversity, and β-diversity in the tropics? Symphonia globulifera, often known as the “wax tree” in indigenous languages becauseof its exudate, is a widespread tree that thrives in different conditions throughout the Neotropics, even though it makes up less than 2% of the trees in any individual forest [4]. Leigh and colleagues use this species as an example of a rare tree’s exploitation of specific niche opportunities that protect it from replacement by competitors and allow increase in numbers despite being initiallyrare, while at the same time promoting the coexistence of diverse species. Historical ecologist Balée [5] points out that for native peoples, Symphonia globulifera is an important economic and ritual species whose wood, saps, resins, and lattices are used for construction, medicines (abortifacient and prevention of menstruation), combustion of torches, and adhesives. Could this value to native...