Population studies of black and gold howler monkeys (Alouatta caraya) in Northern Argentina over the last 20 years.

OKLANDER LI, KOWALEWSKI MM, GONZALEZ V, ZUNINO GE.

Entebbe - UGANDA

Congreso; XXIst International Primatological Society Congress; 2006

International Primatological Society

A population of Alouatta caraya living in semideciduous forest in northern Argentina (near the southern limit of its distribution), was studied in 2003 to evaluate the effects of habitat fragmentation caused by logging. Aerial photographs taken in 1982, 1992, and 2001 were used to compare vegetation maps. These maps were used to evaluate changes in the area covered by forest fragments. From March to June 2003, 10-day monthly surveys of howlers were made in each fragment. A total of 233 individual howlers were counted, belonging to 34 groups plus a solitary adult female. Groups ranged from 2 to 19 individuals (average=6.82), and 23.5% of the groups contained more than one adult male. Adults accounted for 55% of the individuals, immatures for 45%, and infants represented 13% of the total. Data obtained were compared with information available for the same population for 1982 and 1995. Results revealed no changes in the size or the density of fragments. Group sizes and group composition of howlers suggest that the population has remained stable over the past twenty-two years. Ecological density does not appear to be affected by fragmentation and logging, but crude density was low compared with other less-disturbed habitat. The status of the population remains uncertain due to isolation, and there are no protected areas to ensure its stability for the future.