To date, 23 primate species have been identified in Bolivia, grouped in 13 genera and five families. One of the largest groups is the genus Callicebus, of the Pitheciidae family, which in Bolivia is represented by six species: Callicebus aureipalatii, Callicebus donacophilus, Callicebus modestus, Callicebus olallae, Callicebus pallescens and a sixth species of the Amazonian forests of Pando, whose identity has yet to be confirmed. They are medium sized (about 1 kg) and differ from each other by the fur color.
One of the contributions of the Greater Madidi-Tambopata Landscape Conservation Program of WCS was the description of a new species for science, a titi monkey, Callicebus aureipalatii, along the Hondo River in Madidi National Park. It is locally called ‘lucachi’ and its natural habitat is the humid forest of the piedmont and the Amazon basin, west of the Beni River. Its fur is characterized by the golden color on the top of its head, the intense orange coloration of its neck and chest and the reddish color of its arms and legs.
Studies on the behavioral ecology of the species show that social groups can vary from 1 to 12 individuals, but usually are gathered in small family groups of 2 to 6 individuals, and its home range of 16 to 18 hectares. Its population density of 6.2 individuals/km2 indicates that the species is in good conservation condition, with a widely dispersed habitat and diverse food resources.
With the aim to ensure the protection of the species and Madidi National Parks’ diversity, in 2006 an international auction, organized by FUNDESNAP in coordination with SERNAP and WCS, designated its scientific name and raised $us. 650,000.00 to establish a trust fund for Madidi administered by FUNDESNAP. The interest generated by this fund, around $us. 40,000.00 annually since 2007, has allowed SERNAP to strengthen control and monitoring activities in the protected area.
Moreover,in 2002 studies conducted by WCS led to the rediscovery of two Bolivian endemic primate species of the genus Callicebus, also known locally as lucachis: Callicebus modestus and Callicebus olallae. The Olalla brothers made the first records in 1938. Since their description in 1939 there had been no further studies on these species until the research conducted by WCS on their distribution, density, group composition and behavioral ecology.
Its distribution is restricted to areas located in the southeast of Beni Department, between the Beni and Maniqui rivers, in the pre-Andean Amazonian forests and associated flooded savannas. Callicebus modestus habitat are riparian forests and forest islands, covering an area of 1,542 km2 in the municipalities of Reyes, Santa Rosa and San Borja, while Callicebus olallae distribution is even more restricted, with an area of only 162 km2, located almost exclusively in the riverine forests of the Yacuma River, although there is a record along the Maniqui River. Callicebus olallae has one of the smallest distributions of all primate species worldwide.
Both species are very similar in size and the color of their face and hands, but differ in color of their body; C. modestus has an orange brown fur while C. olallae has relatively long fur and it is reddish brown. They live in family groups of 2 to 7 individuals, occupying territories from 7 to 10 hectares. They feed mainly on the fruits and leaves of a variety of plants. They have also been observed consuming insects and other invertebrates.
The population density of C. modestus is 13 ind./km2,which provides an estimate of a total of 20,000 individuals for the species. he population density for C. olallae is 11.8 ind./km2, with a maximum population size of 2,000 individuals. The populations of these species are relatively small compared with other primate species, underlining their threatened status. This is aggravated by natural forest fragmentation in the area that is now intensified by the effects of traditional burning of pastures associated with livestock production. Also, the paving of the North Corridor road, which divides the range of these species, poses a threat to their conservation through habitat loss.
Ecological studies conducted by WCS allowed the reclassification of both species by the IUCN under the category of Endangered (EN) for risk of extinction. Also, both species are now emblems of the Pampas del Yacuma Municipal Protected Area in the municipality of Santa Rosa. The information currently being generated in studies on their behavioral ecology will help better understand the requirements of both endemic species and design strategies that allow population monitoring and the conservation oftheir natural habitats.
An important current activity aims to raise awareness in the municipalities of Reyes and Santa Rosa del Yacuma of the need to conserve the endemic Callicebus species of the Beni Department, mainly through habitat conservation. To that end, WCS is contributing to the implementation of the "Conservation of endemiclucachis of the Beni Department (Callicebus modestus and Callicebus olallae) by outreach strategies" project funded by Conservation Leadership Program (CLP) with scientific information. There have been talks and activities in all the educational units of these municipalities and several rural communities. Ineach community, we assessed the presence of Callicebus modestus populations, with the participation of community members, registering data from areas with higher concentrations of groups to focus conservation actions. Also, local media was involved in broadcasting messages on radio and short videos in television aimed at sensitizing the population.