A review of Peruvian flood plain forests: ecosystems, inhabitants and resource use

Abstract

The lowland Peruvian Amazon remains sparsely populated and densely forested. Few roads exist and rivers provide much of the infrastructure. Over 12% of the area is comprised of flood plains inundated by the larger rivers, but due to their easy access and relatively fertile conditions, they provide a much larger share of the resources extracted in the region, and sustain most of the rural villages. The largest area of annually flooded land, constituting more than 60,000 km2, surrounds the lower reaches of the Ucayali and Marañon rivers above their confluence to the Amazon proper, including almost 90% of the 20,600 km2 large Pacaya-Samiria National Reserve. The entire area is constantly reshaped by erosion and deposition by the two main rivers, but also by smaller rivers which carry fewer sediments and less nutrients. The vegetation constitutes a complex mosaic of habitats defined by combinations of hydrological, physical, chemical and biological characteristics. Sixteen habitats including 12 forest formations are classified and described. Most flood plain inhabitants have lost their native identity, but they descend mostly from Amerindians rather than from recent immigrants, and preserve much knowledge on the flood plain environment and its habitats and uses. They combine agriculture, fishery, hunting and extraction of other forest products, and they market increasing amounts of these products. Growing populations and an increase in the need for monetary incomes as well as in external economic interventions, increasingly endanger economically important flood plain plants, animals and fishes. This is even the case within the Pacaya-Samiria National Reserve, making it urgent to develop and implement sound management systems in the marginal zones of the reserve, and elsewhere in Peruvian flood plains.