Habitat use by western purple-faced langurs Trachypithecus vetulus nestor (Colobinae) in a fragmented suburban landscape

Abstract

As natural habitats around the globe disappear, humans and non-human primates become increasingly engaged in complex interactions, both peaceful and hostile. Sri Lanka's endemic western purple-faced langur Trachypithecus vetulus nestor persists in the majority of its range in complete sympatry with humans. Listed as Critically Endangered by the IUCN and one of the world's top 25 most endangered primates, their survival appears dependent on the tolerance of humans with whom they coexist. Our aims were to augment the limited information on T. v. nestor focusing on group composition and behavioural adaptations in relation to its heavily fragmented habitat. Research was carried out in Talangama Wetlands, Sri Lanka in 2007. The 5 groups varied in size from 11 to 19 individuals Monkeys regularly used fences, rooftops, power lines, and agricultural trees. Two groups of 19 and 16 individuals had home ranges of 3.06 and 2.86 ha respectively. They consumed a variety of foods including fruits, showing dietary flexibility; the fruits and leaves of Arctocarpus heterophyllus were the langurs' most frequently consumed foods. The langurs seem to be adapting to these human-modified environments. Notwithstanding, areas for concern include potentially fatal dangers when crossing between fragments, increasing human-primate conflict and intergroup conflict, and permanent genetic isolation.

Forest fragments become farmland: Dietary Response of wild chimpanzees (Pan troglodytes) to fast‐changing anthropogenic landscapes

“…Recent studies confirm that many primates living in fragmented habitats supplement a natural diet with agricultural foods (e.g. Campbell‐Smith, Campbell‐Smith, Singleton, & Linkie, 2011; Chaves & Bicca‐Marques, 2017; de Freitas, Setz, Araújo, & Gobbi, 2008; Kibaja, 2014; Mekonnen et al, 2012; Moore, Nekaris, & Eschmann, 2010; Pozo‐Montuy, Serio‐Silva, Chapman, & Bonilla‐Sánchez, 2013), a behavior often termed “crop raiding” but which is better described by more neutral terms like “crop foraging” or “crop feeding” (Hill, 2017). Although suggestive of dietary flexibility—and in spite of nutritional benefits—crop feeding is risky, exposing primates to lethal crop protection measures and persecution (McLennan, Hyeroba, Asiimwe, Reynolds, & Wallis, 2012; Paterson, 2005).…”

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“…Kebanyakan spesies Colobinae terkenal dengan sifat segan, pemalu dan kebolehan bersembunyi dengan kehadiran manusia. Namun begitu, beberapa spesies lutong telah berjaya beradaptasi dengan manusia sebagai contoh T. cristatus (lutong kelabu) yang telah berhabituasi dan hidup secara komensalisme dengan manusia di Bukit Melawati, Selangor (Harding 2010) dan T. vetulus di Sri Lanka (Moore et al 2010).…”

Random walk analysis of ranging patterns of sympatric langurs in a complex resource landscape

“…Although a few studies have examined the dietary ecology of S. entellus [Vandercone et al, ] and T. vetulus in Sri Lanka [Dela, ; Hladik, ; Moore et al, ; Vandercone et al, ], our study is the first, to our knowledge, to investigate the movement trajectories of colobines using random walk models.…”