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Kufa CA, Bekele A, Atickem A, Zinner D. Djaffa Mountains guereza ( Colobus guereza gallarum) abundance in forests of the Ahmar Mountains, Ethiopia. Primate Biol 2023; 10:13-23. [PMID: 38039330 PMCID: PMC10654609 DOI: 10.5194/pb-10-13-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/14/2023] [Indexed: 12/03/2023] Open
Abstract
The size and density of a population are essential parameters in primate ecology and conservation. Such information, however, is still scarce for many forest primate species. The Djaffa Mountains guereza (Colobus guereza gallarum) is an endemic Ethiopian taxon for which data about its distribution and population size are missing. Therefore, we aimed to estimate the abundance and population size of the Djaffa Mountains guereza in four forests in the Ahmar Mountains southeast of the Ethiopian Rift Valley. We conducted line-transect surveys in the forests. Within an area of 183 km2 , we sampled 19 transects covering a distance of 75.9 km. We encountered 73 guereza clusters which most likely represent social groups. Since the detection distances and cluster sizes did not differ among the four forests, we applied a conventional distance sampling (CDS) model and estimated a population density of 20.6 clusters per square kilometer, i.e., 109.6 individuals per square kilometer or 20 061 individuals within the complete study area. This abundance is relatively high compared to other C. guereza taxa. However, given that the habitat and population of C . g . gallarum are already highly fragmented, further monitoring of the population and exploration of the possibilities of reconnecting its habitat should be priorities for the conservation of this taxon.
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Affiliation(s)
- Chala Adugna Kufa
- Department of Zoological Sciences, College of Natural Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
- Department of Biology, Faculty of Natural and Computational Sciences, Woldia University, P.O. Box 400, Woldia, Ethiopia
| | - Afework Bekele
- Department of Zoological Sciences, College of Natural Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Anagaw Atickem
- Department of Zoological Sciences, College of Natural Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center (DPZ), Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
- Department of Primate Cognition, Georg August University, 37083 Göttingen, Germany
- Leibniz ScienceCampus "Primate Cognition", 37077 Göttingen, Germany
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Dove S, Böhm M, Freeman R, McRae L, Murrell DJ. Quantifying reliability and data deficiency in global vertebrate population trends using the Living Planet Index. GLOBAL CHANGE BIOLOGY 2023; 29:4966-4982. [PMID: 37376728 DOI: 10.1111/gcb.16841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 04/15/2023] [Indexed: 06/29/2023]
Abstract
Global biodiversity is facing a crisis, which must be solved through effective policies and on-the-ground conservation. But governments, NGOs, and scientists need reliable indicators to guide research, conservation actions, and policy decisions. Developing reliable indicators is challenging because the data underlying those tools is incomplete and biased. For example, the Living Planet Index tracks the changing status of global vertebrate biodiversity, but taxonomic, geographic and temporal gaps and biases are present in the aggregated data used to calculate trends. However, without a basis for real-world comparison, there is no way to directly assess an indicator's accuracy or reliability. Instead, a modelling approach can be used. We developed a model of trend reliability, using simulated datasets as stand-ins for the "real world", degraded samples as stand-ins for indicator datasets (e.g., the Living Planet Database), and a distance measure to quantify reliability by comparing partially sampled to fully sampled trends. The model revealed that the proportion of species represented in the database is not always indicative of trend reliability. Important factors are the number and length of time series, as well as their mean growth rates and variance in their growth rates, both within and between time series. We found that many trends in the Living Planet Index need more data to be considered reliable, particularly trends across the global south. In general, bird trends are the most reliable, while reptile and amphibian trends are most in need of additional data. We simulated three different solutions for reducing data deficiency, and found that collating existing data (where available) is the most efficient way to improve trend reliability, whereas revisiting previously studied populations is a quick and efficient way to improve trend reliability until new long-term studies can be completed and made available.
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Affiliation(s)
- Shawn Dove
- Centre for Biodiversity and Environment Research, University College London, London, UK
- Institute of Zoology, Zoological Society of London, London, UK
| | - Monika Böhm
- Institute of Zoology, Zoological Society of London, London, UK
- Global Center for Species Survival, Indianapolis Zoo, Indianapolis, Indiana, USA
| | - Robin Freeman
- Institute of Zoology, Zoological Society of London, London, UK
| | - Louise McRae
- Institute of Zoology, Zoological Society of London, London, UK
| | - David J Murrell
- Centre for Biodiversity and Environment Research, University College London, London, UK
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Kiffner C, Kioko J, Butynski TM, de Jong YA, Zinner D. Population dynamics of the Manyara monkey ( Cercopithecus mitis manyaraensis) and vervet monkey ( Chlorocebus pygerythrus) in Lake Manyara National Park, Tanzania. Primate Biol 2022; 9:33-43. [PMID: 36267696 PMCID: PMC9562685 DOI: 10.5194/pb-9-33-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/14/2022] [Indexed: 11/07/2022] Open
Abstract
Estimating population densities and their trends over time is essential for understanding primate ecology and for guiding conservation efforts. From 2011 through to 2019, we counted two guenon species during seasonal road transect surveys in Lake Manyara National Park: the Tanzania-endemic Manyara monkey Cercopithecus mitis manyaraensis (International Union for Conservation of Nature and Natural Resources, IUCN, Red List category of "endangered") and the vervet monkey Chlorocebus pygerythrus (Red List category of "least concern"). To account for imperfect detectability, we analysed the data in a line distance sampling framework, fitted species-specific detection functions, and subsequently estimated seasonal densities. To test for seasonal differences and yearly trends in the species-specific density estimates, we fitted generalized additive models. Seasonal point density estimates fluctuated considerably during the 9 years (2011-2019) of our study, ranging from 3 to 29 individuals km - 2 for Manyara monkeys and from 19 to 83 individuals km - 2 for vervet monkeys. Densities of both taxa did not differ seasonally, and we did not detect marked directional population trends. Our study illustrates the utility and limitations of line distance sampling for long-term primate monitoring. Beyond informing primate ecology and management, our results highlight the conservation importance of Lake Manyara National Park for primate conservation.
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Affiliation(s)
- Christian Kiffner
- Center for Wildlife Management Studies, The School for Field Studies, 23601, Karatu, Tanzania,Department of Human Behavior, Ecology and Culture, Max Planck
Institute for Evolutionary Anthropology, 04103 Leipzig, Germany,Human–Wildlife Conflict & Coexistence in Agricultural Landscapes Group,
Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| | - John Kioko
- Center for Wildlife Management Studies, The School for Field Studies, 23601, Karatu, Tanzania
| | - Thomas M. Butynski
- Eastern Africa Primate Diversity and Conservation Program, Nanyuki
10400, Kenya
| | - Yvonne A. de Jong
- Eastern Africa Primate Diversity and Conservation Program, Nanyuki
10400, Kenya
| | - Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077 Göttingen, Germany,Department of Primate Cognition, Georg-August-Universität Göttingen, 37083
Göttingen, Germany,Leibniz Science Campus Primate Cognition, 37077 Göttingen, Germany
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Lala F, Chiyo PI, Omondi P, Okita-Ouma B, Kanga E, Koskei M, Tiller L, Morris AW, Severud WJ, Bump JK. Influence of infrastructure, ecology, and underpass-dimensions on multi-year use of Standard Gauge Railway underpasses by mammals in Tsavo, Kenya. Sci Rep 2022; 12:5698. [PMID: 35383206 PMCID: PMC8983743 DOI: 10.1038/s41598-022-09555-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 03/18/2022] [Indexed: 11/27/2022] Open
Abstract
Rail and road infrastructure is essential for economic growth and development but can cause a gradual loss in biodiversity and degradation of ecosystem function and services. We assessed the influence of underpass dimensions, fencing, proximity to water and roads, Normalized Difference Vegetation Index (NDVI), presence of other species and livestock on underpass use by large and medium-sized mammals. Results revealed hyenas and leopards used the underpasses more than expected whereas giraffes and antelopes used the underpasses less than expected. Generalized linear mixed-effects models revealed that underpass height influenced use by wildlife, with several species preferring to use taller underpasses. Electric fencing increased underpass use by funneling species towards underpasses, except for elephants and black-backed jackal for which it reduced underpass passage. We also found that the use of underpasses by livestock reduced the probability of use by nearly 50% for wildlife species. Carnivore species were more likely to cross underpasses used by their prey. Buffalo, livestock, and hyenas used underpasses characterized by vegetation with higher NDVI and near water sources while baboons, dik-diks and antelope avoided underpasses with high NDVI. Our findings suggest a need for diverse and comprehensive approaches for mitigating the negative impacts of rail on African wildlife.
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Affiliation(s)
- Fredrick Lala
- Wildlife Research and Training Institute, P.O. Box 842-20117, Naivasha, Kenya. .,University of Minnesota, 2003 Upper Buford Circle, St. Paul, MN, 55108-6074, USA.
| | - Patrick I Chiyo
- Department of Biology, Duke University, P.O. Box 90338, Durham, NC, 27708, USA
| | - Patrick Omondi
- Wildlife Research and Training Institute, P.O. Box 842-20117, Naivasha, Kenya
| | | | - Erustus Kanga
- Ministry of Tourism and Wildlife, P. O. Box 41394, Nairobi, 00100, Kenya
| | - Michael Koskei
- Save the Elephants, P.O. Box 54667, Nairobi, 00200, Kenya
| | - Lydia Tiller
- Save the Elephants, P.O. Box 54667, Nairobi, 00200, Kenya
| | - Aaron W Morris
- University of Minnesota, 2003 Upper Buford Circle, St. Paul, MN, 55108-6074, USA
| | - William J Severud
- University of Minnesota, 2003 Upper Buford Circle, St. Paul, MN, 55108-6074, USA
| | - Joseph K Bump
- University of Minnesota, 2003 Upper Buford Circle, St. Paul, MN, 55108-6074, USA
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