This is not a trivial question. Researchers writing about Amazonia very rarely provide a definition. This ambiguity has important research implications, as often when discussing Amazonia those involved have different ideas of what is being discussed… For example, In Meggers’ paper which I reviewed in my previous post, she disagrees with another archaeologist’s definition of Amazonia. Erikson, in his article entitled “Amazonia: the historical ecology of a domesticated landscape”, refers to Amazonia as “the entire region drained by the Amazon River and its tributaries”(Erickson 2008: 158). So, how would you define Amazonia? You could say, like Erickson , that it coincides with the basin of the Amazon River, but then you would be including a big portion of the Andes. But glaciers located 6000 m.s.l. don’t match our idea of a lush Amazonia, do they? Another option could be to consider Amazonia only that part of the Amazon Basin that is covered by rainforest. Well, this looks better, but you would exclude important areas like the savannahs. Moreover, the size of the rainforest changes over time: the boundaries of the rainforest we see today are different from those it had 15000 years ago, and, with the expansion of industrial agriculture, forested areas have been shrinking significantly in the last 20-30 years. It is very unpractical to have to change the limits of what we call Amazonia each time the boundaries of the rainforest move. Meggers (2011) states that: “Amazonia is defined by geographers and ecologists as the portion of tropical lowland South America below 1,500 meters, where the average difference in annual temperature does not exceed 5ºF, rain falls on 130 or more days of the year, and relative humidity normally exceeds 80%. Typical vegetation consists of rainforest, with small enclaves of savannah where soil conditions inhibit plant growth.” However, she doesn’t say who are these “geographers and ecologists” and does not provide any references for this.
While looking for a good paper that defines Amazonia I found out that the European Commission, in collaboration with the Amazon Cooperation Treaty Organization, created in 2005 a task force of experts with the objective of defining the geographical boundaries of Amazonia. Scientists from different disciplines, such as climatology, hydrology, botany, zoology, ecology and biogeography, came together in a two day workshop to reach a consensus (Eva et al. 2005).
The criteria used to draw the map of Amazonia (Fig. 1) were Hydrography, Ecology and Biogeography.
You can download the study here
|Figure 1 -|
UNIT I = Amazon and Tocantins river basins [“Amazon Basin” or “Hydrographical Amazonia”]
Ia = Lowland rainforest biota of the Amazon and Tocantins River basins [“Lowland Amazon
Basin rainforest” or “Amazonia sensu stricto”]
Ib = Andes (non-lowland biota of the Andean Amazon Basin, > 700 m asl)
Ic = Planalto (non-lowland biota of the southern Amazon Basin)
UNIT II = Amazon lowland rainforest types outside Unit I
IIa = Guiana
IIb = Gurupí
Ia + IIa + IIb = Entire Amazon lowland rainforest biome [“Hylaea” or “Amazonia sensu lato”]
I + II = Amazon and Tocantins river basins + Amazon lowland rainforest biome outside the basin
[“Amazonia sensu latissimo”]
As you see in Fig. 1, they have defined Amazonia sensu stricto (the “real” Amazonia) as the area enclosed by the polygon Ia; and Amazonia sensu lato as the area enclosed by the polygons Ia+IIa+IIb (it is not the “real” Amazonia but you can call it Amazonia because it all looks alike). It would be great if, from now on and to avoid misunderstandings, archaeologists, geographers and paleoecologists that work in Amazonia could use this definition. Eva et al. have provided us with valuable operative tools that we can all use. Unfortunately, the European Commission forgot to make their file of the Amazonian boundaries available for download! I have been looking for it everywhere, but haven’t found anything. I asked for it through the EC web page, but I got no answer. A bit disappointing, considered that we paid for it!
Anyway, as I wanted to have a file that can be used in ArcGis, I resolved to digitalize the map of Amazonia myself. I also decided to distribute it. But, for now, you have to contact me via e-mail because I don't know yet how to upload it :-). I will put a link as soon as I figure out how to do it. I hope there is no copyright infringement in this… well, if there is, they will say something …
Erickson, C. L. 2008. Amazonia: the historical ecology of a domesticated landscape. In Handbook of South American archaeology, eds. H. Silverman and W. H. Isbell, 157-183. Berlin: Springer.
Meggers, B. J. 2011. Handbook of South American Archaeology Reviewed by Betty J. Meggers. Revista de Antropología Chilena 43 (1):147-157.
Eva, Hugh D., Huber, Otto, Achard, Frédéric, Balslev, Henrik, Beck, Stephan G., Behling, Hermann, Belward, Alan S., Beuchle, René,, Cleef, Antoine M., Colchester, M., Duivenvoorden, Joost F., Hoogmoed, Marinus Steven, Junk, Wolfgang Johannes, Kabat, P., Kruijt, Bart, Malhi, Yadvinder, Müller, Jan Marco, Pereira, José M. C., Peres, Carlos, Prance, Ghillean, Roberts, John, & Salo, Jukka (2005). A proposal for defining the geographical boundaries of Amazonia Office for Official Publications of the European Communities : EUR 21808-EN