Suitable habitats for endangered frugivorous mammals: small-scale comparison, regeneration forest and chimpanzee density in Kibale National Park, Uganda.

Sarah Bortolamiol,Marianne Cohen,Sabrina Krief,Quentin Vignaud,John Kasenene,Flora Pennec,Protase Rwaburindore,Andrew Seguya,Kevin Potts,Cédric Sueur

doi:10.1371/journal.pone.0102177

Abstract

Landscape patterns and chimpanzee (Pan troglodytes schweinfurthii) densities in Kibale National Park show important variation among communities that are geographically close to one another (from 1.5 to 5.1 chimpanzees/km2). Anthropogenic activities inside the park (past logging activities, current encroachment) and outside its limits (food and cash crops) may impact the amount and distribution of food resources for chimpanzees (frugivorous species) and their spatial distribution within the park. Spatial and temporal patterns of fruit availability were recorded over 18 months at Sebitoli (a site of intermediate chimpanzee density and higher anthropic pressure) with the aim of understanding the factors explaining chimpanzee density there, in comparison to results from two other sites, also in Kibale: Kanyawara (low chimpanzee density) and Ngogo (high density, and furthest from Sebitoli). Because of the post-logging regenerating status of the forest in Sebitoli and Kanyawara, smaller basal area (BA) of fruiting trees most widely consumed by the chimpanzees in Kanyawara and Sebitoli was expected compared to Ngogo (not logged commercially). Due to the distance between sites, spatial and temporal fruit abundance in Sebitoli was expected to be more similar to Kanyawara than to Ngogo. While species functional classes consumed by Sebitoli chimpanzees (foods eaten during periods of high or low fruit abundance) differ from the two other sites, Sebitoli is very similar to Kanyawara in terms of land-cover and consumed species. Among feeding trees, Ficus species are particularly important resources for chimpanzees at Sebitoli, where their basal area is higher than at Kanywara or Ngogo. Ficus species provided a relatively consistent supply of food for chimpanzees throughout the year, and we suggest that this could help to explain the unusually high density of chimpanzees in such a disturbed site.

Highlights

Factors described as unfavorable to endangered species density, such as habitat fragmentation or anthropogenic activities presence, are not necessarily limiting long-term co-existence of wildlife with human activities [1,2,3]
The availability of food resources influences the geographical distribution and population density limits of a species [10,11]. It has been shown [12] that red colobus (Procolobus pennantii) and redtail monkey’s group size (Cercopithecus ascanius) increased with food resource availability within Kibale National Park
We found no dependence between the feeding party size (FPS) and food patch size at Sebitoli during the study period

Summary

Introduction

Factors described as unfavorable to endangered species density, such as habitat fragmentation or anthropogenic activities presence, are not necessarily limiting long-term co-existence of wildlife with human activities [1,2,3]. Anti-poaching strategies [7], chimpanzee behavioral flexibility [8], and adaptability to environmental changes could be the main factors influencing their resilience and future capacity for long-term survival. The availability of food resources influences the geographical distribution and population density limits of a species [10,11]. It has been shown [12] that red colobus (Procolobus pennantii) and redtail monkey’s group size (Cercopithecus ascanius) increased with food resource availability within Kibale National Park. During periods of fruit scarcity or in response to ecological changes, the flexible fission-fusion social structure exhibited by chimpanzees allows them to reduce party sizes (subgroup) in order to decrease potential feeding competition [18,19,20,21,22,23,24]

Methods

Results

Discussion

Conclusion