Late Holocene flooding in the Ecuadorian rain forest

Abstract

SUMMARY 1. The stratigraphy, radiocarbon chronology, sedimentary pigment, and cation records of sediment cores from four lakes in the Ecuadorian rain forest show that regional flooding occurred from about 1300 to 800 ‘BP. Each core contains a stratum of alluvial clay, silt and sand overlain by lacustrine deposits of peat, gyttja or clayey gyttja. Radiocarbon dates show that the onset and termination of the alluvial event was synchronous across the sites. Short‐term, possibly regional, flooding occurred at each of the sites at least once since the major flood. 2. A core from Anangucocha, a black‐water lake, records the geoche‐ mical signature of white‐water incursion during this flooding interval. Sedimentary pigments show that aquatic production at Anañgucocha was low during the lotic interval but rose sharply and remained high within the modern lake period. 3. The Amazon's dynamic river system may have been an important force in promoting and maintaining high floral and faunal diversity.

Approaches to Developing Sustainable Extraction Systems for Tropical Forest Products

“…Deciding what level of impact on the ecosystem is acceptable is made more difficult by the fact that forests are naturally dynamic. Long term climatic cycles (on the order of hundreds of years) cause changes in forest composition both in temperate (Steijlen and Azckrisson 1987) and tropical forests (Wijmstra and van der Hammen 1966, Absy 1979, Frost and Miller 1987. Current forest composition in many areas has been influenced by past cultures in South America (Denevan 1992) and Central America and Mexico (Gomez-Pompa and Kaus 1990).…”

The Rain‐Forest Ecosystem as a Resource for Hunting and Gathering

“…This process of recurrent rejuvenation of rain-forest communities is thought to be a principal cause of high species richness because competitive interactions seldom last long enough for the losers to go locally extinct (Connell 1978;Hubbel 1979;Colinvaux 1987;Salo 1987). In addition, Amazon forests are subject to severe and frequent erosional events that also serve to keep successions in their early stages (Colinvaux et al , 1988Salo et al 1986;Rasanen, Salo, and Kalliola 1987;Frost 1988;Frost and Miller 1987). An important consequence to foragers is that dispersal is vital to rain-forest plants, so that many produce fruits or seeds attractive to animals (Whittaker, Bush, and Richards 1989).…”

“…Amazon pollen diagrams document repeated small-scale disturbance in the vegetation throughout the Holocene (Absy 1979;Liu and Colinvaux 1988;Colinvaux et al 1988;Frost 1988;Bush and Colinvaux 1988). In addition, the western Amazon basin yields records of repeated reworking of the land surface by rivers (Rasanen, Salo, and Kalliola 1987;Salo 1987;Colinvaux 1987) as well as regional flooding Frost and Miller 1987). Disturbances of these kinds seem to be basic properties of the Amazon system.…”

Ecology and management of mahogany (Swietenia macrophyllaKing) in the Chimanes Forest, Beni, Bolivia Is there a future for mahogany?Edited by Andrew MacLellan

“…comm.). There is also palynological and sediment evidence for catastrophic flooding events caused by periodic volcanic activity or changes in local or Andean precipitation regimes (Colinvaux et al, 1985;Frost & Miller, 1987).…”