Ecological flexibility of the western chimpanzee throughout its range: a floristic species use perspective

Details

Supervisors

Thierry Hance

Faculty

Faculté des sciences

Degree label

Master [120] en biologie des organismes et écologie, à finalité approfondie

Abstract

An organism’s capacity to adapt across diverse environmental conditions, or ecological flexibility, remains a fundamental concept for understanding a species’ adaptability throughout its range. The ability for a species to broaden its ecological niche without niche specialization enables that species to occupy large geographical ranges, and inhabit a variety of habitats. Among primates, a taxon who emerged as especially flexible, chimpanzees are exceptionally well-studied. They occupy incredibly diverse ecologies ranging from dry and open savannas to dense tropical forests, showcasing unparalleled flexibility among non-human great apes. Within the four chimpanzee subspecies, Pan troglodytes verus, is considered to demonstrate the highest degree of behavioral diversity, while simultaneously occupying the full breadth of ecological contexts observed for chimpanzees. Nevertheless, the degree to which their specific ecology is similarly flexible remains unclear, and there is value in understanding the extent to which this subspecies achieves this diverse ecology through variation in its floristic use patterns, or if this is achieved by other means. Such questions are imperative to understanding the underlying dynamics of how broadly flexible species with variable niches achieve adaptability across their range. To address these questions, we elucidate and characterize floristic use patterns across western chimpanzee’s range with a focus on nesting and dietary floristic species use. Additionally, we identified a core set of floristic species and genera consistently used by western chimpanzees. With data from 47 sites, we found that western chimpanzees are an exceptionally ecologically flexible taxon, with clear environmental drivers of the patterns of their floristic species use. At least 724 distinct plant species were used for nesting and feeding behavior, with 275 species shared between the behaviors. Their floristic repertoire was broader (i.e., more species used) in forested environments relative to savanna habitats, with their dietary and nesting species breadth positively correlated with tree cover, and rainfall additionally impacting diet species breadth. Several floristic species demonstrate consistently high frequency of use across large geographic scales. However, inter-community overlap in nesting species utilization was relatively low regardless of geographical scales and habitat types. Our results provide the first range-wide analysis of the extraordinary diversity of floristic use patterns in a great ape subspecies. They strongly support the notion that the adaptability of flexible species is facilitated by their modular exploitation of resources. Furthermore, they highlight the fact that remarkable and often unexpected degrees of flexibility can be observed at the subspecies and population level.