Primates of the Valleys of the Rios Jequitinhonha and Mucuri, Brazil: Occurrence and Distribution

We report on a study of the occurrence and distribution of primates in three areas in the valleys of the rios Mucuri and Jequitinhonha in the states of Minas Gerais and Bahia. The areas were chosen on the basis of their classification as priority areas of high biological importance for conservation (numbered 213, 217, and 221) during a regional priority-setting workshop organized by the Brazilian government in 1999. We carried out surveys using a number of methods including line-transect sampling. Seven species were recorded in priority area 217, three in priority area 213, and three in 221. We saw six species in 66 encounters along 167.2 km of line transect surveys. The encounter rate for each species varied from 0.26 encounters/10 km to 2.49 encounters/10 km. Geoffroy’s tufted-ear marmoset (Callithrix geoffroyi) was the most frequently sighted and was particularly abundant in the Mucuri valley. The brown howler monkey (Alouatta guariba) was also relatively common in the Mucuri valley. The northern muriqui (Brachyteles hypoxanthus) was seen in one of the survey sites, the most northerly register for the species. Five of the seven primates in the region are threatened. We found evidence of illegal hunting and selective logging in all the localities surveyed, and conservation measures are needed, specifically: an increase in surveillance against hunting, wood extraction and fires. Minas Gerais is one of the Brazilian states where deforestation levels are still of concern. It has been among the three states with the highest deforestation rates for the past five years, with the Jequitinhonha valley being one of the regions most impacted. The Fazenda Santana is located on the banks of the Rio Jequitinhonha and, despite the intense observed logging, it still has considerable areas of lowland deciduous forest, a rare phytophysiognomy that is now restricted almost entirely to this part of the state of Minas Gerais. The maintenance of some of the forest fragments surveyed would protect nearly 70% of the threatened primates of Minas Gerais, notably Sapajus xanthosternos, Callicebus melanochir, and Brachyteles hypoxanthus.