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Leeds A, Kakule D, Stalter L, Mbeke JK, Fawcett K. Group structure and individual relationships of sanctuary-living Grauer's gorillas (Gorilla beringei graueri). PLoS One 2024; 19:e0295561. [PMID: 38232054 DOI: 10.1371/journal.pone.0295561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/23/2023] [Indexed: 01/19/2024] Open
Abstract
The study of individual social relationships and group structure provides insights into a species' natural history and can inform management decisions for animals living in human care. The Gorilla Rehabilitation and Conservation Education (GRACE) center provides permanent sanctuary for a group of 14 Grauer's gorillas (Gorilla beringei graueri), a critically endangered and poorly studied subspecies of the genus gorilla, in the Democratic Republic of the Congo. We monitored the association patterns of the gorillas at GRACE over eight months and here describe their individual relationships and group structure via multiple social network statistics. The group was highly connected but associations between individuals were weak on average. Social network metrics describe that an adult female was the most gregarious and socially central individual within the group. In fact, adult females were the most gregarious and socially central on average. Group level association patterns were significantly correlated over the study period and across observation types, suggesting the group was socially stable during the eight month study period. The data collected in this study were done so by GRACE caregivers as part of their daily husbandry routine and provided important insights into this group's behavior, ultimately informing on their care, welfare and future release considerations. The methodological approaches implemented here are easily scalable to any primate sanctuary or care facility seeking to use data to inform husbandry and management procedures. Lastly, our study is the first social network analysis to be conducted on Grauer's gorillas and provides tentative insights into the behavior of this poorly studied subspecies. Though more research is needed to evaluate if the findings here are reflective of this subspecies' natural history or the idiosyncrasies of the group.
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Affiliation(s)
- Austin Leeds
- Animals, Science and Environment, Disney's Animal Kingdom®, Lake Buena Vista, Florida, United States of America
| | - Dalmas Kakule
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | - Laura Stalter
- Animals, Science and Environment, Disney's Animal Kingdom®, Lake Buena Vista, Florida, United States of America
| | - Jackson K Mbeke
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | - Katie Fawcett
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
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2
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Iyer N, Kahlenberg SM, Williamson EA, Kyungu J, Syaluha EK, Mbeke JK, de Merode E, Caillaud D. Viability analysis for population reinforcement of Grauer's gorillas at Mount Tshiaberimu, Democratic Republic of the Congo. J Wildl Manage 2023. [DOI: 10.1002/jwmg.22384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Affiliation(s)
- Neetha Iyer
- Department of Anthropology, 328 Young Hall, One Shields Avenue University of California Davis CA 95616 USA
| | - Sonya M. Kahlenberg
- Kasiisi Project 1 Carley Road Lexington MA 02421 USA
- Gorilla Rehabilitation and Conservation Education (GRACE) Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | | | - Jean‐Claude Kyungu
- Institut Congolais pour la Conservation de la Nature, Kinshasa, Democratic Republic of the Congo
| | - Eddy K. Syaluha
- Gorilla Doctors (MGVP, Inc.), Karen C. Drayer Wildlife Health Center University of California Davis CA 95616 USA
| | - Jackson K. Mbeke
- Gorilla Rehabilitation and Conservation Education (GRACE) Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | - Emmanuel de Merode
- Institut Congolais pour la Conservation de la Nature, Goma, Democratic Republic of the Congo
| | - Damien Caillaud
- Department of Anthropology, 328 Young Hall, One Shields Avenue University of California Davis CA 95616 USA
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Morrison RE, Hirwa JP, Ndagijimana F, Vecellio V, Eckardt W, Stoinski TS. Cascading effects of social dynamics on the reproduction, survival, and population growth of mountain gorillas. Anim Conserv 2022. [DOI: 10.1111/acv.12830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- R. E. Morrison
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
- Centre for Research in Animal Behaviour, Department of Psychology University of Exeter Exeter UK
| | - J. P. Hirwa
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - F. Ndagijimana
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - V. Vecellio
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - W. Eckardt
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - T. S. Stoinski
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
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Robbins AM, Manguette ML, Breuer T, Groenenberg M, Parnell RJ, Stephan C, Stokes EJ, Robbins MM. Population dynamics of western gorillas at Mbeli Bai. PLoS One 2022; 17:e0275635. [PMID: 36260834 PMCID: PMC9581538 DOI: 10.1371/journal.pone.0275635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/20/2022] [Indexed: 11/19/2022] Open
Abstract
Long-term studies of population dynamics can provide insights into life history theory, population ecology, socioecology, conservation biology and wildlife management. Here we examine 25 years of population dynamics of western gorillas at Mbeli Bai, a swampy forest clearing in Nouabalé-Ndoki National Park, the Republic of Congo. The Mbeli population more than doubled from 101 to 226 gorillas during the study. After adjusting for a net influx of gorillas into the study population, the increase represents an inherent growth rate of 0.7% per year, with 95% confidence limits between -0.7% and 2.6%. The influx of gorillas mainly involved immigration of individuals into existing study groups (social dispersal), but it also included the appearance of a few previously unknown groups (locational dispersal). The average group size did not change significantly during the study, which is consistent with the possibility that western gorillas face socioecological constraints on group size, even when the population is increasing. We found no significant evidence of density dependence on female reproductive success or male mating competition. The distribution of gorillas among age/sex categories also did not change significantly, which suggests that the population had a stable age structure. Our results provide evidence of population stability or growth for some western gorillas (albeit within a small area). The results highlight the value of law enforcement, long-term monitoring, and protected areas; but they do not diminish the importance of improving conservation for this critically endangered species.
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Affiliation(s)
- Andrew M. Robbins
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- * E-mail:
| | - Marie L. Manguette
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
| | - Thomas Breuer
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
- Division of Developmental Biology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | | | - Richard J. Parnell
- Wildlife Conservation Society, Global Conservation Program, Bronx, NY, United States of America
| | - Claudia Stephan
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
- Division of Developmental Biology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Emma J. Stokes
- Wildlife Conservation Society, Global Conservation Program, Bronx, NY, United States of America
| | - Martha M. Robbins
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
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Städele V, Arandjelovic M, Nixon S, Bergl RA, Bradley BJ, Breuer T, Cameron KN, Guschanski K, Head J, Kyungu JC, Masi S, Morgan DB, Reed P, Robbins MM, Sanz C, Smith V, Stokes EJ, Thalmann O, Todd A, Vigilant L. The complex Y-chromosomal history of gorillas. Am J Primatol 2022; 84:e23363. [PMID: 35041228 DOI: 10.1002/ajp.23363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/27/2021] [Accepted: 01/08/2022] [Indexed: 11/10/2022]
Abstract
Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male-mediated gene flow may have been important in the past, but data on the Y-chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y-linked microsatellite loci resulting in 102 unique Y-haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorillas revealed that mountain (G. b. beringei) and Grauer's (G. b. graueri) gorilla Y-chromosomal haplotypes did not form distinct clusters. These observations suggest structure in the ancestral population with subsequent mixing of differentiated haplotypes by male dispersal for western lowland gorillas, and postisolation migration or incomplete lineage sorting due to short divergence times for eastern gorillas.
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Affiliation(s)
- Veronika Städele
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA.,Institute of Human Origins, Arizona State University, Tempe, Arizona, USA.,Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Mimi Arandjelovic
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Evolutionary and Anthropocene Ecology, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Stuart Nixon
- Field Programmes and Conservation Science, Chester Zoo, North of England Zoological Society, Chester, UK
| | | | - Brenda J Bradley
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA
| | - Thomas Breuer
- WWF Germany, Berlin, Germany.,Mbeli Bai Study, Wildlife Conservation Society, Congo Program, Brazzaville, Republic of the Congo
| | | | - Katerina Guschanski
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.,Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Josephine Head
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Shelly Masi
- Eco-Anthropologie, Muséum National d'Histoire Naturelle, CNRS, Musée de l'Homme, Université de Paris, Paris, France
| | - David B Morgan
- Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, Illinois, USA
| | | | - Martha M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Crickette Sanz
- Department of Anthropology, Washington University in Saint Louis, Saint Louis, Missouri, USA.,Wildlife Conservation Society, Congo Program, Brazzaville, Republic of the Congo
| | | | - Emma J Stokes
- Wildlife Conservation Society, Global Conservation Program, New York City, New York, USA
| | - Olaf Thalmann
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Linda Vigilant
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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