Primates’ Use of Flooded and Unflooded Forests in Peruvian Amazonia

Abstract

The Peruvian Amazon basin is home to communities with some of the highest primate species richness found anywhere in the world. While the Amazon basin is a mosaic of terra firme, igapo, and varzea forests, with primates occupying all of these, there is surprisingly little comprehensive research comparing primate species richness among these forest types. The few studies that have looked at this found lower primate species richness in flooded forests compared to terra firme, presumably due to lower plant species diversity in flooded forests. Most of these studies, however, concentrated on comparisons between terra firme and varzea forests; until recently little work has been done on primates in igapo forests. Over a period of 12 years, beginning in 2001, we sampled primate species richness in igapo and terra firme habitats in the Area de Conservacion Regional Comunal Tamshiyacu Tahuayo (ACRCTT), a communal reserve located in northeastern Peru. We found an equal number of primate species in both igapo and terra firme habitats (11 sympatric primate species in each). Our findings of high primate species richness in both igapo and terra firme forests are likely explained by multiple factors, including the unique characteristics of Peruvian igapo which, perhaps as a result of geographic proximity to the Andes, more closely resembles varzea, with more nutrient-rich soils than is typical of black-water forests farther east in Amazonia. In addition, our findings support earlier suggestions that some primate species’ use of igapo habitat is seasonal. These species may be moving into igapo during periods when fruit, especially that of palms like Mauritia flexuosa, is superabundant there although scarce in terra firme. Thus, during critical times of the year, igapo forests may be critical to maintaining sustainable primate populations and primate species richness in areas with flooded and unflooded forests.