The Ucayali moist forest ecoregion is located entirely in Peru at the foot of the Andes mountains and includes the basin west of the Ucayali river, a major branch of the Amazon river. The Cordillera Oriental, or Eastern Mountain chain runs the length of this region. The landscape of this generally flat sub-Andean zone is dissected with these uplifted highlands. Rainfall ranges from 1600-2500mm annually, and elevations range from 200-1100m above sea-level. Here high mountains rise to the west and feed abundant rivers and streams which become the upper Amazon basin. Forests are transitional here between wet lowland rainforest on the eastern extremes, and premontane moist forests at higher elevations.
Location and General Description
Types and Severity of Threats
Justification of Ecoregion Delineation
These subAndean moist forests are bound by the Andes to the west and the Ucayali River to the east – both of which are formidable barriers to the dispersal of many species. The northern delineation follows the transition of the distinct flooded várzea forests of the Marañon River, and the linework for this section originated from LANDSAT imagery. The northernmost finger of these lowland forests extends into the Cenepa River Valley to the montane forest transition. Southern linework follows the extension of the Andean Cordillera to where it meets the confluence of the Tambo River and Urubamba River – thus forming the Ucayali. We have differentiated this ecoregion from the surrounding lowland forests due to species endemism, particularly butterfly (Brown 1987) due to its current (interfluvial and montane) and past isolation as a Pleistocene refuge (Prance 1987). Delineation of this ecoregion and linework for the montane transition areas follow the Instituto Geográfico Nacional (1987) map classification of "Amazonian tropical forest".
Instituto Geográfico Nacional. 1987. Ecoregiones del Peru. Map 1:5,000,000. Atlas del Peru, Lima, Peru.
Prance, G. 1987. Phytogeographic support for the theory of Pleistocene forest refuges in
the Amazon Basin, based on evidence from distribution patterns in Caryocaracaceae, Chrysobalanaceae, Dichapetalaceae, and Lecythidaceaea. Acta Amazonica 3. Pp 5-28.
Brown, K.S. 1987. Biogeography and evolution of Neotropical Butterflies. Pages 66-104 in T. Whitemore, and G. Pranceeditors, Biogeography and Quaternary History in Tropical America. Oxford Science Publications.
Prepared by: Robin Sears and Jan Schipper
Reviewed by: In process