Using Patch Focals to Study Unhabituated Dry-Habitat Chimpanzees (Pan troglodytes schweinfurthii) and Sympatric Fauna at Issa, Ugalla, Tanzania

Abstract

Researchers studying primate community ecology have largely focused on primate species only, ignoring the interactive role that primates have within their larger communities. However, non-primate species (e.g., birds, bats, and other mammals) can greatly influence the behavioral ecology of primates, especially by competing for food and habitat space. Shifting the focus of research to include these potential non-primate competitors requires a modification in methods. Patch focals, in which areas of habitat are monitored, allow for observation of all animals within a study area, capture resources that are not used by the study species, and are particularly well suited for unhabituated communities, where closely following fauna is not possible. From October 2010 to October 2011, I collected data pertaining to the ecological role of chimpanzees (Pan troglodytes schweinfurthii) at the dry habitat site of Issa, Ugalla, Tanzania using patch focals. I determined habitat use by chimpanzees and other fauna, resulting in a detailed analysis of chimpanzees within their larger faunal community. Despite limited availability of forested habitat, Issa chimpanzees were encountered more often in forest than woodland patches. Non-chimpanzee fauna exhibited habitat use patterns as expected, based on species' preferences at other study sites. Overlap in habitat use, and therefore potential for competition, varied greatly between the different faunal categories and chimpanzees. Most importantly, this project highlights that using patch focals successfully allows for the collection of useful data pertaining to multiple socio-ecological aspects of numerous species at the same time.

Population status of chimpanzees in the Masito‐Ugalla Ecosystem, Tanzania

“…There are two distinct seasons: wet (November-April) and dry (May-October), with annual rainfall between 900 and 1400 mm [Piel et al, 2015]. Chimpanzees use this heterogeneous habitat differentially, with more nests [Stewart & Pruetz, 2013] and observations [Russak, 2014] occurring in gallery forest than in other vegetation types.…”

“…Monitoring these apes is critical given the nature of the threats facing much of Tanzania's wildlife. Specifically, numerous recent reports show that while the primary threat to chimpanzees is habitat loss caused by human settlement expansion and conversion to agriculture, annual burning, logging, and poaching are also playing a role [Davenport et al, 2010;Plumptre et al, 2010;Piel & Stewart, 2013, 2014Piel et al, 2015] and conservationists have focused on establishing priority areas based on remaining chimpanzee habitat. In western Tanzania, human incursion into the Masito area is mostly for conversion of forest into oil palm plantations, but also for slash and burn agriculture [Pintea et al, 2002[Pintea et al, ,2012.…”

Leopard (Panthera pardus) predation on a red-tailed monkey (Cercopithecus ascanius) in the Issa Valley, western Tanzania

“…Evidence of leopard presence is observed consistently at Issa, although less frequently than at primarily forested sites (Table 1). For example, Hernandez-Aguilar (2009) and Stewart and Pruetz (2013) observed evidence once per 2 weeks and once per month, respectively, during two of the first studies to be conducted at Issa (see also Russak 2014). In recent years, direct observations of leopards have become more common.…”

<Note>Savanna Chimpanzees (Pan troglodytes schweinfurthii) Consume and Share Blue Duiker (Philantomba monticola) Meat in the Issa Valley, Ugalla, Western Tanzania

“…The mosaic vegetation structure of the study area is dominated by miombo woodland (Brachystegia, Julbernardia, and Isoberlinia) interspersed with riverine forest, grasslands, and swamps. Russak (2014) recorded 42 mammal and 12 frugivorous bird species including Table 1. Species hunted at Gombe and Mahale, and whether they are present and hunted at Issa, modified from Goodall (1986) and Newton-Fisher (2014).…”