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Western lowland gorilla density and nesting behavior in a Gabonese forest logged for 25 years: implications for gorilla conservation

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Abstract

The tropical forests of the Congo Basin constitute biodiversity refuges that still hold large numbers of species, including endemic and endangered vertebrates. Along with several key species, the critically endangered western lowland gorilla (WLG) potentially contributes to forest dynamics through seed dispersal. Considering the extensive influence of timber harvesting on tropical forest ecosystems, the survival of gorilla populations in logged forests might prove critical for forest ecosystem conservation. We estimated WLG density, through a nest count survey, in a forest in southeast Gabon that has been logged for 25 years. Nesting behavior and habitat use were described and we applied generalized linear models to identify the factors that influence gorilla day and night habitat use. The estimated density of weaned gorillas, 1.5 gorillas km−2, is comparable with estimates from some protected areas and other sustainably managed sites within their range. Habitat type had the greatest influence on nest site distribution. We observed a preference for nesting in open terra firma forest, and open habitats in general, which supports the findings of previous studies. Habitat use during the day was strongly influenced by habitat type and human activities, and to a lesser degree by functional and non-functional roads, and rivers. Our results support the suggestion that logged forests are suitable habitats for WLG if hunting and poaching are controlled. We recommend collaborations between timber operators and scientists to improve the conservation potential of tropical forests and enhance the wildlife-management aspects of logging practices.

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Acknowledgments

The authors thank the Fonds pour la Formation à la Recherche dans l’Industrie et l’Agriculture-Fonds National pour la Recherche Scientifique (FRIA-FNRS, Belgium) for the financial support provided to Barbara Haurez through a Ph.D. grant. The Fonds National pour la Recherche Scientifique, Fonds Léopold III pour l’Exploration et la Conservation de la Nature, Fonds pour la Formation à la Recherche Scientifique en Afrique, Wallonie-Bruxelles International and the École Régionale Post-Universitaire d’Aménagement et de Gestion Intégrés des Forêts et Territoires Tropicaux (ERAIFT) financed the field data collection. We thank partner structures (Precious Woods Gabon, Groupe Millet and Nature +) for technical and logistical support during the field work of this Ph.D. study. We are grateful to Yves Brostaux for his advice in statistical analysis and to an anonymous reviewer for his relevant comments on this paper. Finally, many thanks to all field assistants who helped in data collection, especially to Armand Boubady and Noèl Endahoyi.

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Authors and Affiliations

  1. Laboratory of Tropical and Subtropical Forestry, Unit of Forest and Nature Management, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés 2, 5030, Gembloux, Belgium

    Barbara Haurez, Charles-Albert Petre, Cédric Vermeulen & Jean-Louis Doucet

  2. École Régionale Post-Universitaire d’Aménagement et de Gestion Intégrés des Forêts et Territoires Tropicaux (ERAIFT), B.P. 15373, Kinshasa, Democratic Republic of Congo

    Barbara Haurez, Cédric Vermeulen & Jean-Louis Doucet

  3. Projet Grands Singes (PGS) of the Centre for Research and Conservation, Royal Zoological Society of Antwerp (RZSA), Koningin Astridplein 20–26, 2018, Antwerp, Belgium

    Charles-Albert Petre & Nikki Tagg

  4. Conservation Biology Unit, Section Education and Nature, Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000, Brussels, Belgium

    Charles-Albert Petre

Authors
  1. Barbara Haurez
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  2. Charles-Albert Petre
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  3. Cédric Vermeulen
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  4. Nikki Tagg
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  5. Jean-Louis Doucet
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Correspondence to Barbara Haurez.

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Communicated by Iain James Gordon.

Appendix

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Table 7 Vegetation type classification (adapted from Doucet, 2003)
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Haurez, B., Petre, CA., Vermeulen, C. et al. Western lowland gorilla density and nesting behavior in a Gabonese forest logged for 25 years: implications for gorilla conservation. Biodivers Conserv 23, 2669–2687 (2014). https://doi.org/10.1007/s10531-014-0743-1

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