Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia.
The scale and nature of pre-Columbian human impacts in Amazonia are currently hotly debated. Whereas pre-Columbian people dramatically changed the distribution and abundance of species and habitats in some parts of Amazonia, their impact in other parts is less clear. Pioneer research asked whether their effects reached even further, changing how ecosystems function, but few in-depth studies have examined mechanisms underpinning the resilience of these modifications. Combining archeology, archeobotany, paleoecology, soil science, ecology, and aerial imagery, we show that pre-Columbian farmers of the Guianas coast constructed large raised-field complexes, growing on them crops including maize, manioc, and squash. Farmers created physical and biogeochemical heterogeneity in flat, marshy environments by constructing raised fields. When these fields were later abandoned, the mosaic of well-drained islands in the flooded matrix set in motion self-organizing processes driven by ecosystem engineers (ants, termites, earthworms, and woody plants) that occur preferentially on abandoned raised fields. Today, feedbacks generated by these ecosystem engineers maintain the human-initiated concentration of resources in these structures. Engineer organisms transport materials to abandoned raised fields and modify the structure and composition of their soils, reducing erodibility. The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them follows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use.
McKey
Doyle
D
Université Montpellier II and Centre d'Ecologie Fonctionnelle et Evolutive, Unité Mixte de Recherche 5175 Centre National de la Recherche Scientifique, F-34293 Montpellier Cedex 5, France. doyle.mckey@cefe.cnrs.fr
Rostain
Stéphen
S
Iriarte
José
J
Glaser
Bruno
B
Birk
Jago Jonathan
JJ
Holst
Irene
I
Renard
Delphine
D
D000383:Agriculture / Q000266:history* / Q000379:methods*; D001106:Archaeology; D017753:Ecosystem; D005616:French Guiana; D049690:History, Ancient; D049691:History, Medieval; D006801:Humans; D012987:Soil / Q000032:analysis; D013037:Spatial Behavior / Q000502:physiology*
D012987:Soil
Philos Trans R Soc Lond B Biol Sci. 2007 Feb 28;362(1478):291-307
17255037
Proc Natl Acad Sci U S A. 2002 May 14;99 Suppl 3:7275-9
12011406
Science. 1981 Jul 24;213(4506):399-405
17760172
Science. 2004 Apr 16;304(5669):402-3
15087539
Conserv Biol. 2006 Jun;20(3):709-10
16909562
Science. 1988 Oct 7;242(4875):105-7
17757634
Science. 2003 Sep 19;301(5640):1710-4
14500979
Nature. 2000 Oct 19;407(6806):894-7
11057665
Proc Natl Acad Sci U S A. 2007 Nov 6;104(45):17608-13
17978176
Nature. 2000 Nov 9;408(6809):190-3
11089970
Science. 2005 Jan 28;307(5709):550-5
15618485
Science. 2007 Sep 14;317(5844):1513-6
17872436
Philos Trans R Soc Lond B Biol Sci. 2007 Feb 28;362(1478):187-96
17255028
Science. 2004 Sep 24;305(5692):1926-9
15448261
Science. 2007 Jun 29;316(5833):1866-9
17600209
Trends Ecol Evol. 2008 Mar;23(3):169-75
18255188
Proc Natl Acad Sci U S A. 2007 Dec 26;104(52):20666-71
18093934