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

Abstract

Behavioral flexibility, including an ability to modify feeding behavior, is a key trait enabling primates to survive in forest fragments. In human-dominated landscapes, unprotected forest fragments can become progressively degraded, and may be cleared entirely, challenging the capacity of primates to adjust to the changes. We examined responses of wild chimpanzees (Pan troglodytes schweinfurthii) to major habitat change: that is, clearance of forest fragments for agriculture. Over 7 years, fragments in Bulindi, Uganda, were reduced in size by 80%. We compared the chimpanzees' diet at the start and end of this period of rapid deforestation, using data derived mainly from fecal analysis. Similar to other long-term study populations, chimpanzees in Bulindi have a diverse diet comprising over 169 plant foods. However, extensive deforestation seemed to impact their feeding ecology. Dietary changes after fragment clearance included reduced overall frugivory, reduced intake of figs (Ficus spp.; formerly a dietary "staple" for these chimpanzees), and reduced variety of fruits in fecal samples. Nevertheless, the magnitude of most changes was remarkably minor given the extent of forest loss. Agricultural fruits increased in dietary importance, with crops accounting for a greater proportion of fruits in fecal samples after deforestation. In particular, cultivated jackfruit (Artocarpus heterophyllus) became a "staple" food for the chimpanzees but was scarcely eaten before fragment clearance. Crops offer some nutritional benefits for primates, being high in carbohydrate energy and low in hard-to-digest fiber. Thus, crop feeding may have offset foraging costs associated with loss of wild foods and reduced overall frugivory for the chimpanzees. The adaptability of many primates offers hope for their conservation in fragmented, rural landscapes. However, long-term data are needed to establish whether potential benefits (i.e. energetic, reproductive) of foraging in agricultural matrix habitats outweigh fitness costs from anthropogenic mortality risk for chimpanzees and other adaptable primates. K E Y W O R D S behavioral flexibility, crop feeding, deforestation, foraging adaptations, fragmentation, unprotected habitats

A descriptive study of zoonotic disease risk at the human-wildlife interface in a biodiversity hot spot in South Western Uganda

“…Results from this study reveal community increased community sharing of resources (crops, fruits and water) with wildlife driven by survival needs of the people and wildlife alike as their habitats range continue to shrink due to human encroachment. Studies have highlighted that as the forest fragments become farmland, there has been a dietary change of wildlife to agriculture crops further increasing conflict between human and wildlife [14,26].…”

“…The forest fragments are faced with the increasing challenge of unregulated timber extraction and clearance for agriculture [13]. The human PLOS NEGLECTED TROPICAL DISEASES population (majorly comprised of the Bunyoro, Bakiga and Lugbara tribes) resident in this area commonly live close to forest fragments-often less than 1000ha in size and within 1 km of a forest edge [12,14]. These fragments are inhabited by a mobile population of about 5000 chimpanzees (Pan troglodytes schweinfurthii) that move within and between forest-farm habitats, causing increased conflict with human farming communities [12].…”

Sparse Evidence for Giardia intestinalis, Cryptosporidium spp. and Microsporidia Infections in Humans, Domesticated Animals and Wild Nonhuman Primates Sharing a Farm–Forest Mosaic Landscape in Western Uganda

“…The landscape is a mosaic of farmland, villages, and fragments of riverine forest along watercourses. A resident ‘community’ of chimpanzees, first studied in 2006–2007 [ 91 ], has been studied continuously since 2014 [ 92 ]. Besides the chimpanzees, black and white colobus monkeys are also permanent NHP residents, whereas baboons ( Papio anubis ) and tantalus monkeys ( Chlorocebus tantalus ) are transient visitors.…”

“…NHP in Bulindi have experienced major habitat disturbance: between 2006 and 2014 forest fragments were reduced in size by ca. 80% and converted to farmland [ 92 ]. Rapid habitat change has led to increased foraging in agricultural fields by NHP [ 91 , 92 ] and close encounters occur daily among the chimpanzees, black and white colobus monkeys, people, and domestic animals ( Figure 1 ).…”

Surviving at the extreme: Chimpanzee ranging is not restricted in a deforested human‐dominated landscape in Uganda

“…Democratic Republic of Congo: Hicks et al., 2014; Uganda: McCarthy et al., 2015). Chimpanzees display flexible behaviour in anthropogenic habitats, as illustrated by their propensity to eat agricultural crops (Hockings & McLennan, 2012), which influences their foraging, activity, social grouping and ranging patterns (Bortolamiol et al., 2016; Bryson‐Morrison et al., 2017; Hockings et al, 2009, 2012; Krief et al., 2014; McLennan, 2013; McLennan et al., 2020).…”