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Carvalho JS, Stewart FA, Marques TA, Bonnin N, Pintea L, Chitayat A, Ingram R, Moore RJ, Piel AK. Spatio-temporal changes in chimpanzee density and abundance in the Greater Mahale Ecosystem, Tanzania. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2715. [PMID: 36178009 PMCID: PMC10078593 DOI: 10.1002/eap.2715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/23/2022] [Accepted: 06/16/2022] [Indexed: 06/16/2023]
Abstract
Species conservation and management require reliable information about animal distribution and population size. Better management actions within a species' range can be achieved by identifying the location and timing of population changes. In the Greater Mahale Ecosystem (GME), western Tanzania, deforestation due to the expansion of human settlements and agriculture, annual burning, and logging are known threats to wildlife. For one of the most charismatic species, the endangered eastern chimpanzee (Pan troglodytes schweinfurthii), approximately 75% of the individuals are distributed outside national park boundaries, requiring monitoring and protection efforts over a vast landscape of various protection statuses. These efforts are especially challenging when we lack data on trends in density and population size. To predict spatio-temporal chimpanzee density and abundance across the GME, we used density surface modeling, fitting a generalized additive model to a 10-year time-series data set of nest counts based on line-transect surveys. The chimpanzee population declined at an annual rate of 2.41%, including declines of 1.72% in riparian forests (from this point forward, forests), 2.05% in miombo woodlands (from this point forward, woodlands) and 3.45% in nonforests. These population declines were accompanied by ecosystem-wide declines in vegetation types of 1.36% and 0.32% per year for forests and woodlands, respectively; we estimated an annual increase of 1.35% for nonforests. Our model predicted the highest chimpanzee density in forests (0.86 chimpanzees/km2 , 95% confidence intervals (CIs) 0.60-1.23; as of 2020), followed by woodlands (0.19, 95% CI 0.12-0.30) and nonforests (0.18, 95% CI 0.10-1.33). Although forests represent only 6% of the landscape, they support nearly one-quarter of the chimpanzee population (769 chimpanzees, 95% CI 536-1103). Woodlands dominate the landscape (71%) and therefore support more than a half of the chimpanzee population (2294; 95% CI 1420-3707). The remaining quarter of the landscape is represented by nonforests and supports another quarter of the chimpanzee population (750; 95% CI 408-1381). Given the pressures on the remaining suitable habitat in Tanzania, and the need of chimpanzees to access both forest and woodland vegetation to survive, we urge future management actions to increase resources and expand the efforts to protect critical forest and woodland habitat and promote strategies and policies that more effectively prevent irreversible losses. We suggest that regular monitoring programs implement a systematic random design to effectively inform and allocate conservation actions and facilitate interannual comparisons for trend monitoring, measuring conservation success, and guiding adaptive management.
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Affiliation(s)
- Joana S. Carvalho
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
- School of Built and Natural SciencesUniversity of DerbyDerbyUK
| | - Fiona A. Stewart
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
- Greater Mahale Ecosystem Research and Conservation ProjectDar es SalaamTanzania
- Department of AnthropologyUniversity College LondonLondonUK
| | - Tiago A. Marques
- School of Mathematics and StatisticsUniversity of St. AndrewsSt. AndrewsUK
- Department of Animal BiologyFaculdade de Ciencias da Universidade de LisboaLisbonPortugal
| | - Noemie Bonnin
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | - Lilian Pintea
- Department of Conservation ScienceThe Jane Goodall InstituteWashingtonDistrict of ColumbiaUSA
| | - Adrienne Chitayat
- Institute of Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamNetherlands
| | - Rebecca Ingram
- Greater Mahale Ecosystem Research and Conservation ProjectDar es SalaamTanzania
| | - Richard J. Moore
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | - Alex K. Piel
- Greater Mahale Ecosystem Research and Conservation ProjectDar es SalaamTanzania
- Department of AnthropologyUniversity College LondonLondonUK
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Buys B, van Loon S, Puijk AD. New observations on chimpanzee accumulative stone throwing in Boé, Guinea Bissau. MAMMALIA 2022. [DOI: 10.1515/mammalia-2021-0098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Chimpanzee accumulative stone throwing at trees has been described by Kühl, H.S., Kalan, A.K., Arandjelovic, M., Aubert, F., D'Auvergne, L., Goedmakers, A., Jones, S., Kehoe, L., Regnaut, S., Tickle, A., et al. (2016). Chimpanzee accumulative stone throwing. Sci. Rep. 6: 1–8, but we lack important details about the social and ecological context for this rare behavior. Further observations may enhance future research, as the described observations have not yet been shared in the literature. We analyzed camera trap records from 2010 to 2020 of various research projects conducted in the Boé sector of Gabu Province in south-east Guinea Bissau, West-Africa, to identify ecological and social factors that might potentially influence chimpanzee accumulative stone throwing behavior (on a total of 298 records). From September 2019 until November 2019, we filmed five trees over 48 days to conduct a further exploratory study of this behavior. We discuss the importance of study design when investigating a little-described phenomenon, and the threat posed to chimpanzee populations in West-Africa by the expected expansion of mining activities. More knowledge on chimpanzee accumulative stone throwing is needed as the chimpanzee population is under stress because of increased mining activities in the area. With habitat rapidly being disturbed and destroyed, this population and its rare behavior are increasingly at risk of extermination.
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Affiliation(s)
- Bartelijntje Buys
- Foundation Chimbo , Huningpaed 6 , 8567 LL Oudemirdum , The Netherlands
| | - Sem van Loon
- Foundation Chimbo , Huningpaed 6 , 8567 LL Oudemirdum , The Netherlands
| | - Anouk D. Puijk
- Foundation Chimbo , Huningpaed 6 , 8567 LL Oudemirdum , The Netherlands
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Ordaz-Németh I, Sop T, Amarasekaran B, Bachmann M, Boesch C, Brncic T, Caillaud D, Campbell G, Carvalho J, Chancellor R, Davenport TRB, Dowd D, Eno-Nku M, Ganas-Swaray J, Granier N, Greengrass E, Heinicke S, Herbinger I, Inkamba-Nkulu C, Iyenguet F, Junker J, Bobo KS, Lushimba A, Maisels F, Malanda GAF, McCarthy MS, Motsaba P, Moustgaard J, Murai M, Ndokoue B, Nixon S, Nseme RA, Nzooh Z, Pintea L, Plumptre AJ, Roy J, Rundus A, Sanderson J, Serckx A, Strindberg S, Tweh C, Vanleeuwe H, Vosper A, Waltert M, Williamson EA, Wilson M, Mundry R, Kühl HS. Range-wide indicators of African great ape density distribution. Am J Primatol 2021; 83:e23338. [PMID: 34662462 DOI: 10.1002/ajp.23338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/05/2021] [Accepted: 09/30/2021] [Indexed: 01/23/2023]
Abstract
Species distributions are influenced by processes occurring at multiple spatial scales. It is therefore insufficient to model species distribution at a single geographic scale, as this does not provide the necessary understanding of determining factors. Instead, multiple approaches are needed, each differing in spatial extent, grain, and research objective. Here, we present the first attempt to model continent-wide great ape density distribution. We used site-level estimates of African great ape abundance to (1) identify socioeconomic and environmental factors that drive densities at the continental scale, and (2) predict range-wide great ape density. We collated great ape abundance estimates from 156 sites and defined 134 pseudo-absence sites to represent additional absence locations. The latter were based on locations of unsuitable environmental conditions for great apes, and on existing literature. We compiled seven socioeconomic and environmental covariate layers and fitted a generalized linear model to investigate their influence on great ape abundance. We used an Akaike-weighted average of full and subset models to predict the range-wide density distribution of African great apes for the year 2015. Great ape densities were lowest where there were high Human Footprint and Gross Domestic Product values; the highest predicted densities were in Central Africa, and the lowest in West Africa. Only 10.7% of the total predicted population was found in the International Union for Conservation of Nature Category I and II protected areas. For 16 out of 20 countries, our estimated abundances were largely in line with those from previous studies. For four countries, Central African Republic, Democratic Republic of the Congo, Liberia, and South Sudan, the estimated populations were excessively high. We propose further improvements to the model to overcome survey and predictor data limitations, which would enable a temporally dynamic approach for monitoring great apes across their range based on key indicators.
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Affiliation(s)
- Isabel Ordaz-Németh
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tenekwetche Sop
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Mona Bachmann
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Christophe Boesch
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Wild Chimpanzee Foundation, Leipzig, Germany
| | - Terry Brncic
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | - Damien Caillaud
- Dian Fossey Gorilla Fund International, Atlanta, USA.,Department of Anthropology, University of California, Davis, California, USA
| | | | - Joana Carvalho
- Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, UK
| | - Rebecca Chancellor
- Departments of Anthropology & Sociology and Psychology, West Chester University, West Chester, Pennsylvania, USA
| | - Tim R B Davenport
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | - Dervla Dowd
- Wild Chimpanzee Foundation, Leipzig, Germany
| | | | | | | | | | - Stefanie Heinicke
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Biodiversity Conservation group, German Centre for Integrative Biodiversity Research (iDiv) Halle-Leipzig-Jena, Leipzig, Germany.,Transformation Pathways Research Department, Potsdam Institute for Climate Impact Research, Potsdam, Germany
| | | | | | - Fortuné Iyenguet
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | - Jessica Junker
- Biodiversity Conservation group, German Centre for Integrative Biodiversity Research (iDiv) Halle-Leipzig-Jena, Leipzig, Germany
| | - Kadiri S Bobo
- Department of Forestry, Faculty of Agronomy and Agricultural Sciences, The University of Dschang, Dschang, Cameroon
| | - Alain Lushimba
- IUCN, Regional Program Central and West Africa, Ouagadougou, Burkina Faso
| | - Fiona Maisels
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA.,Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, UK
| | | | - Maureen S McCarthy
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Prosper Motsaba
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | | | - Mizuki Murai
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Bezangoye Ndokoue
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | | | | | | | - Lilian Pintea
- Conservation Science, Jane Goodall Institute, Vienna, USA
| | | | - Justin Roy
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Aaron Rundus
- Department of Psychology, West Chester University, West Chester, Pennsylvania, USA
| | - Jim Sanderson
- Small Wild Cat Conservation Foundation, Corrales, New Mexico, USA
| | - Adeline Serckx
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,The Biodiversity Consultancy Ltd., Cambridge, UK.,Behavioral Biology Unit, Primatology Research Group, University of Liège, Liège, Belgium
| | - Samantha Strindberg
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | - Clement Tweh
- Wild Chimpanzee Foundation, Leipzig, Germany.,School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Hilde Vanleeuwe
- Wildlife Conservation Society, Global Conservation Program, New York, New York, USA
| | | | - Matthias Waltert
- Workgroup on Endangered Species, University of Göttingen, Göttingen, Germany
| | | | - Michael Wilson
- Departments of Anthropology and Ecology, Evolution and Behavior, University of Minnesota, Minneapolis, Minnesota, USA
| | - Roger Mundry
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Hjalmar S Kühl
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Biodiversity Conservation group, German Centre for Integrative Biodiversity Research (iDiv) Halle-Leipzig-Jena, Leipzig, Germany
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Bessone M, Booto L, Santos AR, Kühl HS, Fruth B. No time to rest: How the effects of climate change on nest decay threaten the conservation of apes in the wild. PLoS One 2021; 16:e0252527. [PMID: 34191810 PMCID: PMC8244864 DOI: 10.1371/journal.pone.0252527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/17/2021] [Indexed: 11/18/2022] Open
Abstract
Since 1994, IUCN Red List assessments apply globally acknowledged standards to assess species distribution, abundance and trends. The extinction risk of a species has a major impact on conservation science and international funding mechanisms. Great ape species are listed as Endangered or Critically Endangered. Their populations are often assessed using their unique habit of constructing sleeping platforms, called nests. As nests rather than apes are counted, it is necessary to know the time it takes for nests to disappear to convert nest counts into ape numbers. However, nest decomposition is highly variable across sites and time and the factors involved are poorly understood. Here, we used 1,511 bonobo (Pan paniscus) nests and 15 years of climatic data (2003-2018) from the research site LuiKotale, Democratic Republic of the Congo, to investigate the effects of climate change and behavioural factors on nest decay time, using a Bayesian gamma survival model. We also tested the logistic regression method, a recommended time-efficient option for estimating nest decay time. Our climatic data showed a decreasing trend in precipitation across the 15 years of study. We found bonobo nests to have longer decay times in recent years. While the number of storms was the main factor driving nest decay time, nest construction type and tree species used were also important. We also found evidence for bonobo nesting behaviour being adapted to climatic conditions, namely strengthening the nest structure in response to unpredictable, harsh precipitation. By highlighting methodological caveats, we show that logistic regression is effective in estimating nest decay time under certain conditions. Our study reveals the impact of climate change on nest decay time in a tropical remote area. Failure to account for these changes would invalidate biomonitoring estimates of global significance, and subsequently jeopardize the conservation of great apes in the wild.
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Affiliation(s)
- Mattia Bessone
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Lambert Booto
- LuiKotale Bonobo Project, Centre for Research and Conservation, Royal Zoological Society of Antwerp, Antwerp, Belgium
| | - Antonio R. Santos
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Hjalmar S. Kühl
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Barbara Fruth
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
- LuiKotale Bonobo Project, Centre for Research and Conservation, Royal Zoological Society of Antwerp, Antwerp, Belgium
- Faculty of Biology/Department of Neurobiology, Ludwig Maximilians University of Munich, Planegg-Martinsried, Germany
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Konstanz, Germany
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