"Abundance, Distribution, and Troop Composition of the Black Howler Monkey (Alouatta Pigra) in Different Forest Remnants in the Lachuá Ecoregion"

Abstract

This research analyzes the distribution, abundance and troop composition of the black howler monkey, Alouatta pigra, in the Lachuá ecoregion. The forest remnants where located the monkeys varied in terms of size, type of vegetation cover and isolation distance between each of them the same. In addition, the effect of the "representation" of the inhabitants of the communities with respect to the howler monkey was considered black in the abundance and distribution of these primates.

In a total of L067 hours of searching, 414 individuals were observed, of which 403 (97%) formed 80 troops and 11 (3%) formed extra-troop groups, solitary individuals and one adult female mantled howler monkey, A. palliata, which was part of a troop of A. pigra. It was observed that habitat fragmentation modifies the potential habitat that black howler monkeys can use by limiting the distribution of individuals to the few remnants of forest that persist in the area of ​​influence and to the LLNP. Such remnants are frequently isolated. A greater number of individuals and troops were detected in the patches near the hills, which
It is possibly related to a greater abundance of the ramón tree (Brossimum spp.) near archaeological sites in the area. In addition, an abundance of tamarind (Dialium guianense) and amate (Ficus spp.) food trees was observed in that area. 

The average number of troops in the patches (forested areas less than 4 km2) was 5.19 (±1.97 with a range of 1 1 to 2 individuals), in the hills (area of ​​18.09 km2) it was 5.35 (±1.70 with a range of 8 to 3) and in the PNLL (area of ​​31.74 km2) it was 3.89 (±1.33 with a range of 6 to 3). The average of the relative population density indices was 13.01 ind/km2 in the patches and 6.8 ind/km2 in the hills.
The ecological relative density index in the PNLL was 1.8 and in the patches a range of 1.04 to 700.67 ind/km2 was observed. The composition of the total troops detected (N=80) is as follows: 34% adult male individuals (N=136), 35% adult females (N=142), 6% juvenile males (n=24), 9% juvenile females (N=34), 1% unsexed juveniles (N=5), and 15% infants (N=62). The proportion of adult male individuals was higher in areas with lower density (hills) and a high tendency to polygamous and unimale troops was observed. The number of individuals of A. pigra detected was higher in remnants with forest vegetation cover and in patches that were not very isolated (from 81 to 262 m away).