Surviving in the urban–rural interface: Feeding and ranging behavior of brown howlers (Alouatta guariba clamitans) in an urban fragment in southern Brazil

Abstract

Wild primates that live in urban areas face extreme threats that are less frequent in nonurban fragments, such as the presence of dangerous matrix elements (e.g., roads, power lines, buildings, and a high density of domestic dogs near food patches), that could influence their movements, feeding behavior, and survival. However, the scarcity of studies addressing this issue hinders our understanding of the behavioral adjustments that favor the survival of primates in urban areas. For 12 months, we studied a six-individual group of brown howlers (Alouatta guariba clamitans) in an urban fragment to determine (i) their diet richness and its relationships with food availability, (ii) their daily path length (DPL) and the matrix elements used during movement, and (iii) the main ecological drivers of the DPL. Sampling effort totaled 72 days, 787 hr, and 3,224 instantaneous scans. We found that the diet of brown howlers contained 35 plant species (including seven cultivated crops) belonging to 33 genera and 21 families. The consumption of fruits and young leaves was directly related to their temporal availability. The average DPL (446 m) was smaller than that reported for groups of howlers inhabiting large nonurban fragments. To move between food patches, animals used three main matrix elements: trees, power lines, and roofs. The number of plant species used during the day was the main driver of DPL. Our findings highlighted that the generalist-opportunistic diet of brown howlers and their ability to move across the anthropogenic matrix using artificial elements such as power lines, roofs, and wildlife crossings represent a remarkable part of their behavioral repertory in Lami. However, there are potential costs associated with these strategies, namely, electrocution and predation by domestic dogs. Thus, it is urgent to further investigate how these behaviors could affect the long-term survival of these animals.

Supplemented howler monkeys eat less wild fruits, but do not change their activity budgets

“…Another howler group (hereafter RO), whose composition ranged from three to four individuals (one or two adult males: M2 and M3; two adult females: F3 and F4) due to the immigration of M3 in February 2017 and his emigration in June 2017, was monitored in the RO fragment. The howlers in this group spent most of their time in the 1.6‐ha area, where they moved over the roofs and walls of houses and on the ground, as reported for another group in the region (Corrêa, Chaves, Printes, & Romanowski, ). They also fed on both wild resources available in the altered forest fragments and on the supplements provided by local people.…”

“…Whereas the weak direct influence of the contribution of supplemented biomass to time dedicated to moving can be related to the need of howlers to move in an environment with a highly discontinuous canopy that demanded displacement over house roofs and walls, electrical wires and even on the ground to reach the single (JA; as also reported by Corrêa et al, ) or the scattered (RO) supplementation sites (see El Alami et al, ; Sha & Hanya, 2013a), the wide data dispersion (Figure ) is compatible with the influence of other factors (e.g., distribution and phenology of food sources and weather) on the investment in moving by the study subjects.…”

Howler monkey tolerance to habitat shrinking: Lifetime warranty or death sentence?

“…In addition to resource scarcity, diverse factors can contribute to the extirpation of howler monkeys, particularly from smaller habitat patches immersed in human‐altered landscapes. Howlers are killed by domestic dogs and people or are run over by cars when they descend to the ground to cross canopy gaps or to move between discrete habitat patches to feed, or they are electrocuted when they move along power lines (Bicca‐Marques & Calegaro‐Marques, ; Chaves, Fernandes, Oliveira, & Bicca‐Marques, ; Corrêa, Chaves, Printes, & Romanowski, ; Jerusalinsky et al, ; Lokschin, Printes, Cabral, & Buss, ; Pozo‐Montuy & Serio‐Silva, ; Pozo‐Montuy et al, ; Prates & Bicca‐Marques, ).…”

Eventos de electrocución de Aotus lemurinus (Primates: Aotidae) en los Andes Centrales de Colombia

“…Además del daño causado por el contacto directo con los cables, si el corto circuito no es mortal, el animal puede morir por el golpe en caída libre o por el ataque de depredadores mientras se repone (Bevanger 1999). Los eventos de electrocución han sido reportados para diferentes especies de primates tanto del Viejo Mundo como Macaca mulatta (Kumar & Kumar 2015) y Colobus angolensis (Katsis et al 2018) y del Nuevo Mundo como los del género Alouatta (Lokschin et al 2007;Petrucci et al 2009;Corrêa et al 2018) y las especies Saimiri oerstedii (Boinski et al 1998), Callithrix penicillata (Pereira et al 2019) y Aotus lemurinus (Castaño et al 2010;Saavedra-Rodríguez et al 2013).…”

“…Particularmente en Colombia, los registros publicados de electrocución de primates son escasos y están restringidos precisamente a la especie A. lemurinus en bosques andinos del Eje Cafetero y el Valle del Cauca (Castaño et al 2010;Saavedra-Rodríguez et al 2013 El riesgo de electrocución para especies de primates se intensifica cuando los individuos utilizan estructuras antropogénicas como techos y líneas eléctricas, lo cual ha sido evidente en especies neotropicales como Alouatta guariba (Corrêa et al 2018). La mitad de los registros de electrocución de individuos de A. lemurinus ocurrieron en zonas urbanas; además, algunos eventos de electrocución se dieron en redes eléctricas distanciadas en más de diez metros a las ramas de los árboles, lo que sugiere que estos individuos podrían estar usando las redes eléctricas para largos recorridos, y posiblemente también los techos de las casas o el suelo de las calles para moverse.…”