Habitat fragmentation and population size of the black and gold howler monkey (Alouatta caraya) in a semideciduous forest in Northern Argentina

Abstract

A population of black and gold howler monkeys (Alouatta caraya) living near the southern limit of its distribution in a semideciduous forest located in northern Argentina was studied in 2003 to evaluate the possible effects of habitat fragmentation - owing to logging - on its density and social organization within it. Aerial photographs taken in 1982, 1992, and 2001 were used to compare maps of vegetation. 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 232 individual howlers were counted, belonging to 34 groups plus a solitary adult female. Groups ranged from 2 to 19 individuals (mean = 6.82, SD = 4.23), and 21% 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 significant changes in the area of fragments, the crude and ecological density of howlers, and group composition. Group sizes and group composition of howlers suggest that the population remained stable over the past 22 years. The density, number of groups, and individuals appears not to be affected by fragmentation and logging, but crude density was low compared with other less-disturbed habitats. The status of the population remains uncertain owing to isolation, and because there are no protected areas to ensure its stability for the future.

Primate Research and Conservation in Northern Argentina: The Field Station Corrientes (Estación Biológica de Usos Múltiples –EBCo)

“…These results support the contention that howler monkeys do not have a fixed birth season, and that the observed variation in the timing of births appears to represent a facultative behavioral response to changes in food availability [see 5]. On the other hand, comparative studies of the population from 1982 to 2004 suggest that howlers can cope relatively well with moderate deforestation and fragmentation of the forest [5,15]. However, recent studies indicate an incipient process of isolation for the population of howlers living in an area of 5,000 ha surrounding the EBCo [17].…”

Habitat degradation impacts black howler monkey (Alouatta pigra) gastrointestinal microbiomes

“…provides an exceptional model for understanding how variation in host habitat and diet impacts GI microbiome structure, and ultimately, host nutrition and health. Howlers can consume a leaf-heavy diet (Milton, 1980;Lambert, 1998;Estrada and Coates-Estrada, 2005;Di Fiore and Campbell, 2007), permitting them to occupy areas with limited resource availability and to persist longer in degraded habitats than more frugivorous primate taxa (Estrada and Coates-Estrada, 1996;Zunino et al, 2007). As many leaves contain high levels of resistant fiber and toxins, GI microbiome contributions to daily energy flows through metabolism of xenobiotics are critical to howler nutrition (Milton, 1979;Lambert, 1998;Lambert and Fellner, 2012).…”

Consumo de néctar por <i>Aotus lemurinus</i> y su rol como posible polinizador de las flores de <i>Inga edulis</i> (Fabales: Mimosoideae)

“…The climate is subtropical with an average annual temperature of 21.7° C and an average annual of rainfall of 1,230 mm; the rainfall decreases slightly in the winter (July to August) (Zunino et al, 2007). The site presents a fragmented forest and the vegetation is characterized by dense, semideciduous upland and riparian forests, open lowland forests with palm trees, and grasslands (Zunino et al, 2007).…”

“…The site presents a fragmented forest and the vegetation is characterized by dense, semideciduous upland and riparian forests, open lowland forests with palm trees, and grasslands (Zunino et al, 2007). The forest has been heavily modified by logging, the presence of cattle, and burning (Zunino et al, 2007). In addition, there are some individuals of exotic vegetation such as Citrus spp, Grevillea robusta, Hovenia dulcis, and Melia azedarach.…”