Troop Size and Human‐Modified Habitat Affect the Ranging Patterns of a Chacma Baboon Population in the Cape Peninsula, South Africa

Abstract

Differences in group size and habitat use are frequently used to explain the extensive variability in ranging patterns found across the primate order. However, with few exceptions, our understanding of primate ranging patterns stems from studies of single groups and both intra- and inter-specific meta-analyses. Studies with many groups and those that incorporate whole populations are rare but important for testing socioecological theory in primates. We quantify the ranging patterns of nine chacma baboon troops in a single population and use Spearman rank correlations and generalized linear mixed models to analyze the effects of troop size and human-modified habitat (a proxy for good quality habitat) on home range size, density (individuals/km(2) ), and daily path length. Intrapopulation variation in home range sizes (1.5-37.7 km(2) ), densities (1.3-12.1 baboons/km(2) ), and daily path lengths (1.80-6.61 km) was so vast that values were comparable to those of baboons inhabiting the climatic extremes of their current distribution. Both troop size and human-modified habitat had an effect on ranging patterns. Larger troops had larger home ranges and longer daily path lengths, while troops that spent more time in human-modified habitat had shorter daily path lengths. We found no effect of human-modified habitat on home range size or density. These results held when we controlled for the effects of both a single large outlier troop living exclusively in human-modified habitat and baboon monitors on our spatial variables. Our findings confirm the ability of baboons, as behaviorally adaptable dietary generalists, to not only survive but also to thrive in human-modified habitats with adjustments to their ranging patterns in accordance with current theory. Our findings also caution that studies focused on only a small sample of groups within a population of adaptable and generalist primate species may underestimate the variability in their respective localities.

30 Days in the Life: Daily Nutrient Balancing in a Wild Chacma Baboon

“…These landscape transformations will, at the very least, dramatically reduce the availability of the pine nuts and acorns that comprised 44% of the energy intake for our subject. While some baboon troops in the Cape Peninsula subsist almost exclusively on fynbos vegetation, supplemented by marine resources [32], the energetically rich exotic resources and human-derived foods found in Tokai allow a far higher population density and shorter daily path lengths compared to some other troops [56]. The conversion to fynbos will thus likely include a transition period for the Tokai baboons as they behaviorally and demographically adjust to the new patterns of food availability and associated lower carrying capacity of the area.…”

The ecological determinants of baboon troop movements at local and continental scales

“…We also found that DPLs were shorter where troops experienced anthropogenic influence. Anthropogenic influence was not considered by Dunbar [ 29 ] in his original model, but has since been highlighted as an important factor mediating DPLs [ 22 , 33 ]. This is because baboons in human-modified habitats typically have access to high quality and predictable food resources meaning baboons are able to sate their nutritional requirements within a smaller daily ranging distance, e.g.…”

“…crops or food/waste) that occur in human modified habitats (e.g. [ 20 - 22 ]), DPLs are found to be reduced and not predicted well by models that include rainfall and group size as predictors [ 33 ]. We consider primate species number on the basis that a high number of primate species may result in increased levels of inter-specific competition, which is known to drive longer DPLs, especially in frugivorous primates (e.g.…”

“…Our understanding of the ecological determinants of baboon day path lengths at a finer (local) scale comes primarily from arid savannah habitats [ 9 , 36 - 40 ], even when considering more recent studies on the topic [ 13 , 22 , 33 , 41 - 46 ]. To provide a fuller analysis of the ecological determinants of movement at a local scale, and to complement our continental scale analyse (see above), we investigated the daily movements of two troops of yellow baboons, Papio cynocephalus , inhabiting the primate-rich, seasonal, and predominantly woodland habitat of the Issa Valley in Ugalla, western Tanzania.…”

Adaptive space use by baboons (Papio ursinus) in response to management interventions in a human-changed landscape

“…In the Cape Peninsula, South Africa, the lack of a buffer area between the Table Mountain National Park (TMNP) and the city of Cape Town results in high levels of spatial overlap between people and baboons (Hoffman & O'Riain, 2012a). A lack of by-laws to enable the efficient policing of resident behaviour and properties adjacent to TMNP translates into baboons exploiting urban areas to access waste bins, fruiting trees, residential houses, shops and even people carrying food (van Doorn, O'Riain & Swedell, 2010;Kaplan et al, 2011;Hoffman & O'Riain, 2012b). As a result, the Cape Peninsula baboon population is gaining international notoriety as a major pest species.…”