Accurate estimates of a primate’s home range are important, yet methods vary greatly. This paper examines the accuracy of minimum convex polygon (MCP), adaptive kernel (AK) and fixed kernel (FK) estimators by comparing home range estimates of northern bearded saki monkeys (Chiropotes satanas chiropotes) living in forest fragments and continuous forest in the Brazilian Amazon area. MCP was more accurate than AK and FK in calculating home and day range when sample size was small, and AK overestimated range most frequently. It is important to consider the various home range methods, as the appropriate method may depend on sample size and the species’ behavioral ecology.

Previous studies have used home range size to predict a species' vulnerability to forest fragmentation. Northern bearded saki monkeys (Chiropotes satanas chiropotes) are medium-bodied frugivores with large home ranges, but sometimes they reside in forest fragments that are smaller than the species' characteristic home range size. Here we examine how travel and spatial patterns differ among groups living in forest fragments of 3 size classes (1 ha, 10 ha, and 100 ha) versus continuous forest. We collected data in 6 research cycles from JulyAugust 2003 and January 2005-June 2006 at the Biological Dynamics of Forest Fragments Project (BDFFP), north of Manaus, Brazil. For each cycle, we followed the monkeys at each study site from dawn until dusk for 3 consecutive days, and recorded their location. Although bearded saki monkeys living in 10-ha and 1-ha fragments had smaller day ranges and traveled shorter daily distances, they traveled greater distances than expected based on the size of the forest fragment. Monkeys in the small fragments revisited a greater percentage of feeding trees each day, traveled in more circular patterns, and used the fragments in a more uniform pattern than monkeys in the continuous forest. Our results suggest that monkeys in the small fragments maximize their use of the forest, and that the preservation of large tracts of forest is essential for species conservation. Species with large home ranges sometimes inhabit forest fragments, but doing so can alter behavior, demographics, and ecology, and the monkeys may be vulnerable to stochastic events.

Habitat loss, and subsequent fragmentation, can increase the amount of forest edge. Primate species vary in their responses to such changes in their habitat. We studied the movement ecology of a group of reddish-brown cuxiú monkeys (Chiropotes sagulatus, Pitheciidae) in a small (13 ha), isolated forest remnant that was <3% of the species’ typical home range in the region. Every 5 min we recorded the group’s latitude and longitude, and the behavior of all individuals in sight. We calculated distance, speed, and trajectory of travel routes, and distance from every location to the nearest forest edge. Using Lidar data, we calculated canopy height. Cuxiús traveled in all cardinal directions, but they turned left more often than right, and they traveled at a faster speed to locations where the monkeys fed than where they did not eat. Although cuxiús used forest from the edge to the interior, they concentrated their movements and activities >30 m from the forest edge. Furthermore, their food sites were located less often near the forest edge, and canopy height of food trees near the forest edge was lower than canopy height of food trees at a greater distance from the edge. Although edge effects impacted the monkeys’ movement, trees >15 m at the forest edge can provide resources. Future research can examine ecological variables in more detail with the movement patterns.