Paleoriverine Features of the Amazon Lowlands: Human Use of the ‘Arena Negra’ Soils of Lake Charo, Northeastern Peru

Abstract

Amazonia has long been divided by observers into two distinct environments — the upland (or terra firme) and the lowlands (or várzea) — a distinction that pervades the literature on subjects ranging from prehistory, archaeology, and Amerindian cultures to biological diversity, natural resource use, and agricultural development. The upland environment, lying above the floodplain of the Amazon River and its tributaries, offers a stable substrate, old forests, sparse game and soils of limited agricultural potential. In contrast, the lowland environment is highly dynamic and unstable, with young forests, abundant aquatic fauna, and nutrient-rich alluvium. Such depictions, however, are challenged by a growing body of research that points to high soil heterogeneity on the uplands (and some of high native fertility), the extensive occurrence of anthrosols — terra preta soils — on the Brazilian uplands (see chapters in this book; Lehmann et al. 2004), and the recognition of paleoriverine land forms that lie beyond the active floodplain of Amazonian rivers, but below the upland (Salo et al. 1986; Puhakka et al. 1992). Whereas terra preta soils appear to be frequently encountered along major river courses and in many interfluvial areas of the Brazilian Amazon, far fewer terra preta sites have been identified in the Upper Amazon and such sites tend to be found on river bluffs.