The area where the languages of the People of the Center is spoken, the North West Amazon, is one of the world’s most diverse areas in various respects. Its diversity in botanical and zoological species correlates with a diversity in languages and cultures. Geographically, this region is characterized by a generally flat landscape covered by lush rain forest, drained by numerous small rivers which feed into several large rivers that originate in the Andes and feed into the Amazon, still over 3,000 kilometers away from the Atlantic Ocean. With respect to its human population, the North West Amazon is characterized by a large number of small ethnic groups, often numbering no more than a few hundred. These groups are remarkably mobile, some of them still nomadic, often travelling long distances. A linguistic map of this area truly resembles a patchwork of languages belonging to a number of different linguistic families. These include representatives of some of the larger South American language families, such as Arawak and Carib, as well as a number of smaller language families that are confined to the region, such as the Witotoan languages. In addition, the area is characterized by a large number of isolate (or unclassified) languages, such as Andoke.
For more detail, see http://corpus1.mpi.nl/qfs1/media-archive/dobes_data/Center/Info/1.1_Habitat_English.pdf