1
|
Huijsmans TERG, Van Soom A, Smits K, Wauters J, Hagan D, Hildebrandt TB. Elephant Gestation: Insights Into Idiopathic Abortions and Stillbirth. Zoo Biol 2024. [PMID: 39258751 DOI: 10.1002/zoo.21867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 08/29/2024] [Indexed: 09/12/2024]
Abstract
The declining African and Asian elephant populations emphasize the importance of a backup population. Successful reproduction in captivity plays a key role in maintaining such a genetically diverse ex situ population but is challenged by reproductive loss in the form of abortions and stillbirths. The elephants' biphasic prolactin pattern led us to predict a higher incidence of abortions during the time of reduced prolactin concentrations. Therefore, this study focuses on the identification of months during elephant gestation which are prone to loss of pregnancy. A metric was developed to identify the fetal age of aborted calves based on the fetal mass using a regression model. Data on idiopathic abortions in captive and wild elephants collected from zoos, tourist camps, semi-captive, and free-ranging populations since 1974 were analyzed, revealing a significantly higher prevalence of abortions during the 15th and 17th month of gestation. Additionally, the prevalence of stillbirths in the 22nd month of gestation between 2000 and 2023 was assessed. Although stillbirths showed a declining trend over time, the average prevalence between 2019 and 2023 was still 2.8%. Consequently, the 15th, 17th, and 22nd month of gestation were identified as stages prone to pregnancy loss. These findings underscore the necessity of researching risk factors and preventative measures for pregnancy loss in these 3 months, especially exploring a possible link with prolactin during the 15th and 17th month of gestation. The identification of stages prone to fetal loss is a key step towards enhancing elephant reproductive success and welfare.
Collapse
Affiliation(s)
- Tim E R G Huijsmans
- Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Ann Van Soom
- Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katrien Smits
- Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Jella Wauters
- Department of Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- Laboratory of Integrative Metabolomics, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - David Hagan
- Jacksonville Zoo and Gardens, Jacksonville, Florida, USA
| | - Thomas B Hildebrandt
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- Freie Universitaet Berlin, Berlin, Germany
| |
Collapse
|
2
|
Ausband DE, Rebholz PF, Petrillo L. The effects of human-caused mortality on mammalian cooperative breeders: a synthesis. Biol Rev Camb Philos Soc 2024. [PMID: 39219435 DOI: 10.1111/brv.13133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 08/13/2024] [Accepted: 08/15/2024] [Indexed: 09/04/2024]
Abstract
Human-caused mortality can be pervasive and even highly selective for individuals in groups of cooperative breeders. Many studies of cooperative breeders, however, do not address human-caused mortality. Similarly, studies focused on the effects of human-caused mortality on wildlife populations often do not consider the ecology of cooperative breeders. We searched the literature and identified 58 studies where human-caused mortality affected a group characteristic, vital rate, or population state of a cooperative breeder. Of studies reporting population growth or decline, 80% reported a link between human-caused mortality and population declines in cooperative breeders. Such studies often did not identify the mechanism behind population declines, but 28% identified concurrent declines in adult survival and another 21% reported concurrent declines in recruitment or reproduction. There was little overlap between the cooperative breeding and human-caused mortality literatures, limiting our ability to accrue knowledge. Future work would be beneficial if it (i) identified the vital rate(s) causing population declines, (ii) leveraged management actions such as lethal removal to ask questions about the ecology of group-living in cooperative breeders, and (iii) used insights from cooperative breeding theory to inform management actions and conservation of group-living species.
Collapse
Affiliation(s)
- David E Ausband
- U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, 875 Perimeter Drive, MS 1141, Moscow, 83844, Idaho, USA
| | - Peter F Rebholz
- U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, 875 Perimeter Drive, MS 1141, Moscow, 83844, Idaho, USA
- Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, 875 Perimeter Drive, MS 1141, Moscow, 83844, Idaho, USA
| | - Lindsay Petrillo
- U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, 875 Perimeter Drive, MS 1141, Moscow, 83844, Idaho, USA
- Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, 875 Perimeter Drive, MS 1141, Moscow, 83844, Idaho, USA
| |
Collapse
|
3
|
Rallings T, Kempes CP, Yeakel JD. On the Dynamics of Mortality and the Ephemeral Nature of Mammalian Megafauna. Am Nat 2024; 204:274-288. [PMID: 39179233 DOI: 10.1086/731331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2024]
Abstract
AbstractEnergy flow through consumer-resource interactions is largely determined by body size. Allometric relationships govern the dynamics of populations by impacting rates of reproduction as well as alternative sources of mortality, which have differential impacts on smaller to larger organisms. Here we derive and investigate the timescales associated with four alternative sources of mortality for terrestrial mammals: mortality from starvation, mortality associated with aging, mortality from consumption by predators, and mortality introduced by anthropogenic subsidized harvest. The incorporation of these allometric relationships into a minimal consumer-resource model illuminates central constraints that may contribute to the structure of mammalian communities. Our framework reveals that while starvation largely impacts smaller-bodied species, the allometry of senescence is expected to be more difficult to observe. In contrast, external predation and subsidized harvest have greater impacts on the populations of larger-bodied species. Moreover, the inclusion of predation mortality reveals mass thresholds for mammalian herbivores, where dynamic instabilities may limit the feasibility of megafaunal populations. We show how these thresholds vary with alternative predator-prey mass relationships, which are not well understood within terrestrial systems. Finally, we use our framework to predict the harvest pressure required to induce mass-specific extinctions, which closely align with previous estimates of anthropogenic megafaunal exploitation in both paleontological and historical contexts. Together our results underscore the tenuous nature of megafaunal populations and how different sources of mortality may contribute to their ephemeral nature over evolutionary time.
Collapse
|
4
|
Huang RM, Maré C, Guldemond RAR, Pimm SL, van Aarde RJ. Protecting and connecting landscapes stabilizes populations of the Endangered savannah elephant. SCIENCE ADVANCES 2024; 10:eadk2896. [PMID: 38181078 PMCID: PMC10776014 DOI: 10.1126/sciadv.adk2896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/01/2023] [Indexed: 01/07/2024]
Abstract
The influence of protected areas on the growth of African savannah elephant populations is inadequately known. Across southern Africa, elephant numbers grew at 0.16% annually for the past quarter century. Locally, much depends on metapopulation dynamics-the size and connections of individual populations. Population numbers in large, connected, and strictly protected areas typically increased, were less variable from year to year, and suffered less from poaching. Conversely, populations in buffer areas that are less protected but still connected have more variation in growth from year to year. Buffer areas also differed more in their growth rates, likely due to more threats and dispersal opportunities in the face of such dangers. Isolated populations showed consistently high growth due to a lack of emigration. This suggests that "fortress" conservation generally maintains high growth, while anthropogenic-driven source-sink dynamics within connected conservation clusters drive stability in core areas and variability in buffers.
Collapse
Affiliation(s)
- Ryan M. Huang
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Celesté Maré
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Robert A. R. Guldemond
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Stuart L. Pimm
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Rudi J. van Aarde
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| |
Collapse
|
5
|
Prado NA, Armstrong EE, Brown JL, Goldenberg SZ, Leimgruber P, Pearson VR, Maldonado JE, Campana MG. Genomic resources for Asian (Elephas maximus) and African savannah elephant (Loxodonta africana) conservation and health research. J Hered 2023; 114:529-538. [PMID: 37246890 DOI: 10.1093/jhered/esad034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/26/2023] [Indexed: 05/30/2023] Open
Abstract
We provide novel genomic resources to help understand the genomic traits involved in elephant health and to aid conservation efforts. We sequence 11 elephant genomes (5 African savannah, 6 Asian) from North American zoos, including 9 de novo assemblies. We estimate elephant germline mutation rates and reconstruct demographic histories. Finally, we provide an in-solution capture assay to genotype Asian elephants. This assay is suitable for analyzing degraded museum and noninvasive samples, such as feces and hair. The elephant genomic resources we present here should allow for more detailed and uniform studies in the future to aid elephant conservation efforts and disease research.
Collapse
Affiliation(s)
- Natalia A Prado
- Biology Department, College of Arts and Sciences, Adelphi University, Garden City, NY, United States
- Center for Conservation Genomics, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, United States
- Endocrinology Research Laboratory, Center for Species Survival, Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, VA, United States
| | - Ellie E Armstrong
- Department of Biology, Stanford University, Stanford, CA, United States
- School of Biological Sciences, Washington State University, Pullman, WA, United States
| | - Janine L Brown
- Endocrinology Research Laboratory, Center for Species Survival, Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, VA, United States
| | - Shifra Z Goldenberg
- Conservation Ecology Center, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, United States
- Conservation Science and Wildlife Health, San Diego Zoo Wildlife Alliance, Escondido, CA, United States
| | - Peter Leimgruber
- Conservation Ecology Center, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, United States
| | - Virginia R Pearson
- Glenn Rall Laboratory, Fox Chase Cancer Center, Philadelphia, PA, United States
| | - Jesús E Maldonado
- Center for Conservation Genomics, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, United States
| | - Michael G Campana
- Center for Conservation Genomics, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, United States
| |
Collapse
|
6
|
Individual identification and photographic techniques in mammalian ecological and behavioural research—Part 2: Field studies and applications. Mamm Biol 2023. [DOI: 10.1007/s42991-023-00344-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
|
7
|
Chan SCY, Karczmarski L, Lin W, Zheng R, Ho YW, Guo L, Mo Y, Lee ATL, Or CKM, Wu Y. An unknown component of a well-known population: socio-demographic parameters of Indo-Pacific humpback dolphins (Sousa chinensis) at the western reaches of the Pearl River Delta region. Mamm Biol 2023. [DOI: 10.1007/s42991-022-00335-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
8
|
Chan SCY, Chui SYS, Pretorius Y, Karczmarski L. Estimating population parameters of African elephants: a photographic mark-recapture application in a South African protected area. Mamm Biol 2023. [DOI: 10.1007/s42991-022-00334-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
9
|
Ndlovu M, Madiri T, Madhlamoto D, Tadyanehondo K, Vambe A, Mungoni E. Age-sex structure of drought-driven African elephant (Loxodonta africana) mortality in Hwange National Park, Zimbabwe. SCIENTIFIC AFRICAN 2022. [DOI: 10.1016/j.sciaf.2022.e01459] [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] Open
|
10
|
Mukeka JM, Ogutu JO, Kanga E, Piepho HP, Røskaft E. Long-term trends in elephant mortality and their causes in Kenya. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.975682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
High mortality poses a serious threat to sustainable conservation of the African elephant (Loxodonta africana). Using detected carcass data collected by the Kenya Wildlife Service (KWS) during 1992-2017, we analyze temporal and spatial variation in elephant mortality in Kenya. We investigate the major mortality causes and means used to kill elephants, carcass category, tusk recovery status, variation in mortality with elephant age and sex classes, differences between inside and outside protected areas (PAs), the Proportion of Illegally Killed Elephants (PIKE) and the overall mortality rate (MR — the number of dead/number of live elephants in a given year). In total 9,182 elephant deaths were recorded during the 26 years. Elephant mortality increased over time and was attributed primarily to natural (33.1%) and human-related causes, particularly ivory poaching (31.5%) and human-elephant conflicts (19.9%). Elephant mortality varied across Kenya’s 47 counties in correspondence with variation in elephant population size and was the highest in the leading elephant range counties of Taita Taveta, Laikipia, Samburu and Meru. Mortality was higher for males and adults and outside the protected areas. Most elephant carcasses had tusks (75.1%) but a few did not (12.5%). Yearly PIKE values peaked in 2012, the year with the highest poaching levels in Kenya during 1992-2017. MR increased throughout 1992-2017. Temporal variation in elephant mortality probability was significantly influenced by human and livestock population densities, average annual maximum temperature and total annual rainfall and the strength of these influences varied across the seven leading elephant range counties of Kenya. Natural processes are increasingly contributing to elephant mortality likely due to climate change and the associated food and water stress, exacerbated by contracting range. Enhancing anti-poaching and strategies for mitigating climate change impacts and human-elephant conflict and reducing range contraction while sustaining habitat connectivity can help reduce mortality and promote elephant conservation. Strengthening enforcement of international wildlife laws can further reduce illegal trade in tusks and killing of elephants.
Collapse
|
11
|
Scherer L, Bingaman Lackey L, Clauss M, Gries K, Hagan D, Lawrenz A, Müller DWH, Roller M, Schiffmann C, Oerke AK. The historical development of zoo elephant survivorship. Zoo Biol 2022; 42:328-338. [PMID: 36074074 DOI: 10.1002/zoo.21733] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/09/2022]
Abstract
In the discussion about zoo elephant husbandry, the report of Clubb et al. (2008, Science 322: 1649) that zoo elephants had a "compromised survivorship" compared to certain non-zoo populations is a grave argument, and was possibly one of the triggers of a large variety of investigations into zoo elephant welfare, and changes in zoo elephant management. A side observation of that report was that whereas survivorship in African elephants (Loxodonta africana) improved since 1960, this was not the case in Asian elephants (Elephas maximus). We used historical data (based on the Species360 database) to revisit this aspect, including recent developments since 2008. Assessing the North American and European populations from 1910 until today, there were significant improvements of adult (≥10 years) survivorship in both species. For the period from 1960 until today, survivorship improvement was significant for African elephants and close to a significant improvement in Asian elephants; Asian elephants generally had a higher survivorship than Africans. Juvenile (<10 years) survivorship did not change significantly since 1960 and was higher in African elephants, most likely due to the effect of elephant herpes virus on Asian elephants. Current zoo elephant survivorship is higher than some, and lower than some other non-zoo populations. We discuss that in our view, the shape of the survivorship curve, and its change over time, are more relevant than comparisons with specific populations. Zoo elephant survivorship should be monitored continuously, and the expectation of a continuous trend towards improvement should be met.
Collapse
Affiliation(s)
- Lara Scherer
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | | | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | | | - David Hagan
- Indianapolis Zoo, Indianapolis, Indiana, USA
| | | | | | | | | | - Ann-Kathrin Oerke
- European Elephant Service, Endocrinology Laboratory, German Primate Center, Goettingen, Germany
| |
Collapse
|
12
|
Guldemond RAR, Louw CJ, Maré C, Nørgaard C, van Aarde RJ. Demographic responses of an insular elephant population to removal as a management intervention. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Robert A. R. Guldemond
- Conservation Ecology Research Unit, Department of Zoology & Entomology University of Pretoria Hatfield South Africa
| | - Cornelius J. Louw
- Conservation Ecology Research Unit, Department of Zoology & Entomology University of Pretoria Hatfield South Africa
| | - Celesté Maré
- Conservation Ecology Research Unit, Department of Zoology & Entomology University of Pretoria Hatfield South Africa
| | - Camilla Nørgaard
- Conservation Ecology Research Unit, Department of Zoology & Entomology University of Pretoria Hatfield South Africa
| | - Rudi J. van Aarde
- Conservation Ecology Research Unit, Department of Zoology & Entomology University of Pretoria Hatfield South Africa
| |
Collapse
|
13
|
Parker JM, Wittemyer G. Orphaning stunts growth in wild African elephants. CONSERVATION PHYSIOLOGY 2022; 10:coac053. [PMID: 35919453 PMCID: PMC9341231 DOI: 10.1093/conphys/coac053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/23/2022] [Accepted: 07/25/2022] [Indexed: 05/29/2023]
Abstract
Orphans of several species suffer social and physiological consequences such as receiving more aggression from conspecifics and lower survival. One physiological consequence of orphaning, stunted growth, has been identified in both humans and chimpanzees, but has not been assessed in a non-primate species. Here, we tested whether wild African elephant orphans show evidence of stunted growth. We measured individually known female elephants in the Samburu and Buffalo Springs National Reserves of Kenya, with a rangefinder capable of calculating height, to estimate a von Bertalanffy growth curve for female elephants of the study population. We then compared measurements of known orphans and non-orphans of various ages, using a Bayesian analysis to assess variation around the derived growth curve. We found that orphans are shorter for their age than non-orphans. However, results suggest orphans may partially compensate for stunting through later growth, as orphans who had spent a longer time without their mother had heights more similar to non-orphans. More age mates in an individual's family were associated with taller height, suggesting social support from peers may contribute to increased growth. Conversely, more adult females in an individual's family were associated with shorter height, suggesting within-group competition for resources with older individuals may reduce juvenile growth. Finally, we found a counterintuitive result that less rainfall in the first 6 years of life was correlated with taller height, potentially reflecting the unavoidable bias of measuring individuals who were fit enough to survive conditions of low rainfall as young calves. Reduced growth of individuals has been shown to reduce survival and reproduction in other species. As such, stunting in wildlife orphans may negatively affect fitness and represents an indirect effect of ivory poaching on African elephants.
Collapse
Affiliation(s)
- Jenna M Parker
- Corresponding author: San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA.
| | - George Wittemyer
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
- Graduate Degree Program in Ecology, Colorado State University, 102 Johnson Hall, Fort Collins, CO 80523, USA
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO 80523, USA
| |
Collapse
|
14
|
Parker JM, Brown JL, Hobbs NT, Boisseau NP, Letitiya D, Douglas-Hamilton I, Wittemyer G. Social support correlates with glucocorticoid concentrations in wild African elephant orphans. Commun Biol 2022; 5:630. [PMID: 35835816 PMCID: PMC9283395 DOI: 10.1038/s42003-022-03574-8] [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: 10/18/2021] [Accepted: 06/10/2022] [Indexed: 12/25/2022] Open
Abstract
Social relationships have physiological impacts. Here, we investigate whether loss of the mother/offspring relationship has lasting effects on fecal glucocorticoid metabolite (fGCM) concentrations in wild African elephant orphans several years following their mothers’ deaths. We find no difference in fGCM concentrations between orphans and nonorphans, but find lower fGCM concentrations in elephants with more age mates in their family. We also unexpectedly identify lower concentrations in orphans without their natal family versus nonorphans and natal orphans, which we speculate may be due to the development of hypocortisolism following a prolonged period without familial support. An index of plant productivity (i.e. food) shows the largest correlation with fGCM concentrations. Our findings indicate no lasting differences in glucocorticoid concentrations of surviving orphan elephants who are with their family, suggest the presence of age mates may reduce glucocorticoid concentrations in elephants, and emphasize that basic survival needs are the primary regulators of the stress response. Remaining with the family group may reduce long-term stress effects in orphaned African elephants.
Collapse
Affiliation(s)
- J M Parker
- Graduate Degree Program in Ecology, Colorado State University, 102 Johnson Hall, Fort Collins, CO, 80523, USA. .,Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO, 80523, USA. .,Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi, 00200, Kenya.
| | - J L Brown
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA, 22630, USA
| | - N T Hobbs
- Graduate Degree Program in Ecology, Colorado State University, 102 Johnson Hall, Fort Collins, CO, 80523, USA.,Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, 80523, USA
| | - N P Boisseau
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA, 22630, USA
| | - D Letitiya
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi, 00200, Kenya
| | - I Douglas-Hamilton
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi, 00200, Kenya.,Department of Zoology, Oxford University, Oxford, OX1 3PS, UK
| | - G Wittemyer
- Graduate Degree Program in Ecology, Colorado State University, 102 Johnson Hall, Fort Collins, CO, 80523, USA.,Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO, 80523, USA.,Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi, 00200, Kenya
| |
Collapse
|
15
|
Hauenstein S, Jassoy N, Mupepele A, Carroll T, Kshatriya M, Beale CM, Dormann CF. A systematic map of demographic data from elephant populations throughout Africa: implications for poaching and population analyses. Mamm Rev 2022. [DOI: 10.1111/mam.12291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Severin Hauenstein
- Department of Biometry and Environmental System Analysis University of Freiburg 79106FreiburgGermany
- Department of Biology University of York YorkYO10 5DDUK
| | - Noémi Jassoy
- Department of Biometry and Environmental System Analysis University of Freiburg 79106FreiburgGermany
| | - Anne‐Christine Mupepele
- Department of Biometry and Environmental System Analysis University of Freiburg 79106FreiburgGermany
- Department of Nature Conservation and Landscape Ecology University of Freiburg Freiburg79106Germany
| | - Thea Carroll
- CITES Secretariat – MIKE Programme United Nations Environment Programme 30552‐00100NairobiKenya
| | - Mrigesh Kshatriya
- CITES Secretariat – MIKE Programme United Nations Environment Programme 30552‐00100NairobiKenya
| | | | - Carsten F. Dormann
- Department of Biometry and Environmental System Analysis University of Freiburg 79106FreiburgGermany
| |
Collapse
|
16
|
Nunney L. Cancer suppression and the evolution of multiple retrogene copies of TP53 in elephants: a re‐evaluation. Evol Appl 2022; 15:891-901. [PMID: 35603034 PMCID: PMC9108310 DOI: 10.1111/eva.13383] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/27/2022] [Accepted: 04/02/2022] [Indexed: 11/28/2022] Open
Abstract
Evolving to become bigger and/or longer lived should increase cancer susceptibility, but this predicted increase is not observed, a contradiction named Peto's paradox. A solution is that cancer suppression evolves to minimize cancer susceptibility, and the discovery of 19 retrogene (RTG) copies of the tumor suppressor gene TP53 in the African elephant (Loxodonta africana) is increasingly cited as a classic example of such adaptive suppression. However, classic examples need rigorous evaluation and an alternative hypothesis is that the RTGs spread by genetic drift. This study shows that before its duplication, the ancestral elephant RTG was already truncated from 390 amino acids to 157 by a frameshift mutation, and that 14 of the 19 copies are now truncated to ≤88 amino acids. There was no compelling evidence of either positive or negative selection acting on these 88 codons, and the pattern of RTG accumulation fits a neutral model with a duplication rate of ~10−6 per generation. It is concluded that there is no evidence supporting the hypothesis that the 19 elephant RTGs spread to fixation by selection; instead, the evidence indicates that these RTGs accumulated primarily by segmental duplication and drift. It is shown that the evolutionary multistage model of carcinogenesis (EMMC) predicts the recruitment of 1–2 independently acting tumor suppressor genes to suppress the increased cancer risk in elephants, so it is possible that one or a few RTGs may have been favored by selection resulting in the known enhanced sensitivity of elephant cells to DNA damage. However, the analysis does not provide any support for either a direct (via conserved TP53 activity) or indirect (via supporting canonical TP53 function) role of the RTGs sequences, so that the presence of multiple copies of TP53 retrogenes in elephants needs to be further justified before being used as a classic example of tumor suppression in large‐bodied animals.
Collapse
Affiliation(s)
- Leonard Nunney
- Department of Evolution, Ecology, and Organismal Biology University of California Riverside 900 University Avenue Riverside CA 92521 USA
| |
Collapse
|
17
|
Wiśniewska M, Puga-Gonzalez I, Lee P, Moss C, Russell G, Garnier S, Sueur C. Simulated poaching affects global connectivity and efficiency in social networks of African savanna elephants—An exemplar of how human disturbance impacts group-living species. PLoS Comput Biol 2022; 18:e1009792. [PMID: 35041648 PMCID: PMC8797174 DOI: 10.1371/journal.pcbi.1009792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 01/28/2022] [Accepted: 12/23/2021] [Indexed: 11/19/2022] Open
Abstract
Selective harvest, such as poaching, impacts group-living animals directly through mortality of individuals with desirable traits, and indirectly by altering the structure of their social networks. Understanding the relationship between disturbance-induced, structural network changes and group performance in wild animals remains an outstanding problem. To address this problem, we evaluated the immediate effect of disturbance on group sociality in African savanna elephants—an example, group-living species threatened by poaching. Drawing on static association data from ten free-ranging groups, we constructed one empirically based, population-wide network and 100 virtual networks; performed a series of experiments ‘poaching’ the oldest, socially central or random individuals; and quantified the immediate change in the theoretical indices of network connectivity and efficiency of social diffusion. Although the social networks never broke down, targeted elimination of the socially central conspecifics, regardless of age, decreased network connectivity and efficiency. These findings hint at the need to further study resilience by modeling network reorganization and interaction-mediated socioecological learning, empirical data permitting. The main contribution of our work is in quantifying connectivity together with global efficiency in multiple social networks that feature the sociodemographic diversity likely found in wild elephant populations. The basic design of our simulation makes it adaptable for hypothesis testing about the consequences of anthropogenic disturbance or lethal management on social interactions in a variety of group-living species with limited, real-world data.
Collapse
Affiliation(s)
- Maggie Wiśniewska
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
- * E-mail:
| | - Ivan Puga-Gonzalez
- Institutt for global utvikling og samfunnsplanlegging, Universitetet i Agder, Kristiansand, Norway
- Center for Modeling Social Systems at NORCE, Kristiansand, Norway
| | - Phyllis Lee
- Amboseli Trust for Elephants, Nairobi, Kenya
- Faculty of Natural Science, University of Stirling, Stirling, United Kingdom
| | | | - Gareth Russell
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Simon Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Cédric Sueur
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
- Institut Universitaire de France, Paris, France
| |
Collapse
|
18
|
Lee PC, Moss CJ, Njiraini N, Poole JH, Sayialel K, Fishlock VL. Cohort consequences of drought and family disruption for male and female African elephants. Behav Ecol 2021. [DOI: 10.1093/beheco/arab148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Cohort effects, reflecting early adversity or advantage, have persisting consequences for growth, reproductive onset, longevity, and lifetime reproductive success. In species with prolonged life histories, cohort effects may establish variation in age-sex structures, while social structure may buffer individuals against early adversity. Using periods of significant ecological adversity, we examined cohort effects for male and female elephants (Loxodonta africana) over almost 50 years in Amboseli, Kenya. Mortality spiked during severe droughts with highest mortality among calves under 2 years and females over 40 years. Deaths of oldest females resulted in social disruption via matriarch turnover, with potential impacts on resource acquisition for survivors. We predicted that survivors of high mortality and social challenges would have altered life-history trajectories, with later age at first reproduction and reduced age-specific fertility for females and slow transitions to independence and late-onset of potential mating or musth among males. Contrary to expectations, there were no persisting early drought effects on female age at first conception while matriarch loss around puberty accelerated reproductive onset. Experience of an early life drought did not influence age-specific reproductive rates once females commenced reproduction. Males who survived an early drought exhibited complex consequences: male age at family independence was later with larger peer cohort size, but earlier with drought in year of independence (13.9 vs 14.6 years). Early drought had no effect on age at first musth, but male reproductive onset was weakly associated with the number of peers (negative) and age at independence (positive).
Collapse
Affiliation(s)
- Phyllis C Lee
- Amboseli Trust for Elephants, Langata, Nairobi, Kenya
- Behaviour & Evolution Research Group, Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, UK
| | | | | | - Joyce H Poole
- ElephantVoices, Buskhellinga 3, 3236 Sandefjord, Norway
| | | | - Vicki L Fishlock
- Amboseli Trust for Elephants, Langata, Nairobi, Kenya
- Centre for Ecology and Conservation, College of Life & Environmental Sciences, University of Exeter, UK
| |
Collapse
|
19
|
Allen CRB, Croft DP, Brent LJN. Reduced older male presence linked to increased rates of aggression to non-conspecific targets in male elephants. Proc Biol Sci 2021; 288:20211374. [PMID: 34933598 PMCID: PMC8692974 DOI: 10.1098/rspb.2021.1374] [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] [Indexed: 12/24/2022] Open
Abstract
Males in many large mammal species spend a considerable portion of their lives in all-male groups segregated from females. In long-lived species, these all-male groups may contain individuals of vastly different ages, providing the possibility that behaviours such as aggression vary with the age demographic of the social environment, as well as an individual's own age. Here, we explore social factors affecting aggression and fear behaviours in non-musth male African elephants (Loxodonta africana) aggregating in an all-male area. Adolescent males had greater probabilities of directing aggressive and fearful behaviours to non-elephant targets when alone compared to when with other males. All males, regardless of age, were less aggressive towards non-elephant targets (e.g. vehicles and non-elephant animals) when larger numbers of males from the oldest age cohort were present. The presence of older males did not influence the probability that other males were aggressive to conspecifics or expressed fearful behaviours towards non-elephant targets. Older bulls may police aggression directed towards non-elephant targets or may lower elephants' perception of their current threat level. Our results suggest male elephants may pose an enhanced threat to humans and livestock when adolescents are socially isolated, and when fewer older bulls are nearby.
Collapse
Affiliation(s)
- Connie R. B. Allen
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK,Elephants for Africa, 5 Balfour Road, London N5 2HB, UK,School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Darren P. Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| | - Lauren J. N. Brent
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| |
Collapse
|
20
|
Illegal settlement in the Babile Elephant Sanctuary is threatening the resident elephant population. ORYX 2021. [DOI: 10.1017/s0030605320001088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Abstract
The Babile Elephant Sanctuary in Ethiopia was established in 1970 specifically to protect its elephants Loxodonta africana. They were once part of a larger population that ranged in eastern Ethiopia and northern Somalia but that was largely extirpated during the 20th century. Since its establishment, the Sanctuary has experienced severe anthropogenic pressure, inadequate government support, and civil conflict. Mapping was undertaken to analyse the rate of human immigration into the Sanctuary in 2006, 2014 and 2017, as part of an assessment of the Sanctuary's effectiveness in protecting its resident elephant population and in mitigating anthropogenic pressures. From 2006 to 2017 the number of illegal houses in the Sanctuary increased from 18,000 to > 50,000, of which > 32,000 were in the area in which elephants range. This settlement, coupled with high demand for natural resources, has resulted in significant habitat destruction and could also have exacerbated human–elephant conflict. Elephant conservation and monitoring by the Born Free Foundation were challenging because of ethnic conflict; rural and political stability is required if efforts to protect wildlife are to be successful. Unless these issues are resolved and the integrity of the Sanctuary is restored, this elephant population will be extirpated in the near future.
Collapse
|
21
|
Chusyd DE, Ackermans NL, Austad SN, Hof PR, Mielke MM, Sherwood CC, Allison DB. Aging: What We Can Learn From Elephants. FRONTIERS IN AGING 2021; 2:726714. [PMID: 35822016 PMCID: PMC9261397 DOI: 10.3389/fragi.2021.726714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/03/2021] [Indexed: 11/13/2022]
Abstract
Elephants are large-brained, social mammals with a long lifespan. Studies of elephants can provide insight into the aging process, which may be relevant to understanding diseases that affect elderly humans because of their shared characteristics that have arisen through independent evolution. Elephants become sexually mature at 12 to 14 years of age and are known to live into, and past, their 7th decade of life. Because of their relatively long lifespans, elephants may have evolved mechanisms to counter age-associated morbidities, such as cancer and cognitive decline. Elephants rely heavily on their memory, and engage in multiple levels of competitive and collaborative relationships because they live in a fission-fusion system. Female matrilineal relatives and dependent offspring form tight family units led by an older-aged matriarch, who serves as the primary repository for social and ecological knowledge in the herd. Similar to humans, elephants demonstrate a dependence on social bonds, memory, and cognition to navigate their environment, behaviors that might be associated with specializations of brain anatomy. Compared with other mammals, the elephant hippocampus is proportionally smaller, whereas the temporal lobe is disproportionately large and expands laterally. The elephant cerebellum is also relatively enlarged, and the cerebral cortex is highly convoluted with numerous gyral folds, more than in humans. Last, an interesting characteristic unique to elephants is the presence of at least 20 copies of the TP53 tumor suppressor gene. Humans have only a single copy. TP53 encodes for the p53 protein, which is known to orchestrate cellular response to DNA damage. The effects of these multiple copies of TP53 are still being investigated, but it may be to protect elephants against multiple age-related diseases. For these reasons, among others, studies of elephants would be highly informative for aging research. Elephants present an underappreciated opportunity to explore further common principles of aging in a large-brained mammal with extended longevity. Such research can contribute to contextualizing our knowledge of age-associated morbidities in humans.
Collapse
Affiliation(s)
- Daniella E. Chusyd
- Department of Epidemiology and Biostatistics, Indiana University-Bloomington, Bloomington, IN, United States
- *Correspondence: Daniella E. Chusyd,
| | - Nicole L. Ackermans
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Steven N. Austad
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, United States
- Nathan Shock Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Patrick R. Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Michelle M. Mielke
- Division of Epidemiology, Department of Quantitative Health Sciences and Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, George Washington University, Washington, DC, United States
| | - David B. Allison
- Department of Epidemiology and Biostatistics, Indiana University-Bloomington, Bloomington, IN, United States
| |
Collapse
|
22
|
Wittemyer G, Daballen D, Douglas‐Hamilton I. Differential influence of human impacts on age‐specific demography underpins trends in an African elephant population. Ecosphere 2021. [DOI: 10.1002/ecs2.3720] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- George Wittemyer
- Department of Fish, Wildlife and Conservation Biology Colorado State University Fort Collins Colorado USA
- Graduate Degree Program in Ecology Colorado State University Fort Collins Colorado USA
- Save the Elephants Nairobi Kenya
| | | | - Iain Douglas‐Hamilton
- Save the Elephants Nairobi Kenya
- Department of Zoology University of Oxford Oxford UK
| |
Collapse
|
23
|
Parker JM, Webb CT, Daballen D, Goldenberg SZ, Lepirei J, Letitiya D, Lolchuragi D, Leadismo C, Douglas-Hamilton I, Wittemyer G. Poaching of African elephants indirectly decreases population growth through lowered orphan survival. Curr Biol 2021; 31:4156-4162.e5. [PMID: 34343478 DOI: 10.1016/j.cub.2021.06.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/18/2021] [Accepted: 06/29/2021] [Indexed: 10/20/2022]
Abstract
Prolonged maternal care is vital to the well-being of many long-lived mammals.1 The premature loss of maternal care, i.e., orphaning, can reduce offspring survival even after weaning is complete.2-5 However, ecologists have not explicitly assessed how orphaning impacts population growth. We examined the impact of orphaning on population growth in a free-ranging African elephant population, using 19 years of individual-based demographic monitoring data. We compared orphan and nonorphan survival, performed a sensitivity analysis to understand how population growth responds to the probability of being orphaned and orphan survival, and investigated how sensitivity to these orphan parameters changed with level of poaching. Orphans were found to have lower survival compared to nonorphaned age mates, and population growth rate was negatively correlated with orphaning probability and positively correlated with orphan survival. This demonstrates that, in addition to its direct effects, adult elephant death indirectly decreases population growth through orphaning. Population growth rate's sensitivity to orphan survival increased for the analysis parameterized using only data from years of more poaching, indicating orphan survival is more important for population growth as orphaning increases. We conclude that orphaning substantively decreases population growth for elephants and should not be overlooked when quantifying the impacts of poaching. Moreover, we conclude that population models characterizing systems with extensive parental care benefit from explicitly incorporating orphan stages and encourage research into quantifying effects of orphaning in other social mammals of conservation concern.
Collapse
Affiliation(s)
- Jenna M Parker
- Graduate Degree Program in Ecology and Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO 80523, USA; Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya.
| | - Colleen T Webb
- Graduate Degree Program in Ecology and Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA
| | - David Daballen
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| | - Shifra Z Goldenberg
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya; Conservation Ecology Center, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA 22630, USA; Institute for Conservation Research, San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
| | - Jerenimo Lepirei
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| | - David Letitiya
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| | - David Lolchuragi
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| | - Chris Leadismo
- Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| | | | - George Wittemyer
- Graduate Degree Program in Ecology and Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO 80523, USA; Save the Elephants, Marula Manor, Marula Lane, Karen, Nairobi 00200, Kenya
| |
Collapse
|
24
|
Nhleko ZN, Ahrens R, Ferreira SM, McCleery RA. Poaching is directly and indirectly driving the decline of South Africa's large population of white rhinos. Anim Conserv 2021. [DOI: 10.1111/acv.12720] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zoliswa N. Nhleko
- Interdisciplinary Program in Ecology University of Florida Gainesville FL USA
- Savanna Node Scientific Services SANParks Skukuza South Africa
| | - Robert Ahrens
- Fisheries and Aquatic Sciences Program University of Florida Gainesville FL USA
- Fisheries Research and Monitoring Division NOAA Pacific Islands Fisheries Science Center Honolulu HI USA
| | - Sam M. Ferreira
- Savanna Node Scientific Services SANParks Skukuza South Africa
| | - Robert A. McCleery
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| |
Collapse
|
25
|
Athira TK, Vidya TNC. Elephant Social Systems: What Do We Know and How Have Molecular Tools Helped? J Indian Inst Sci 2021. [DOI: 10.1007/s41745-021-00226-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
26
|
Allen CRB, Brent LJN, Motsentwa T, Weiss MN, Croft DP. Importance of old bulls: leaders and followers in collective movements of all-male groups in African savannah elephants (Loxodonta africana). Sci Rep 2020; 10:13996. [PMID: 32883968 PMCID: PMC7471917 DOI: 10.1038/s41598-020-70682-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/29/2020] [Indexed: 11/09/2022] Open
Abstract
In long-lived social species, older individuals can provide fitness benefits to their groupmates through the imparting of ecological knowledge. Research in this area has largely focused on females in matrilineal societies where, for example, older female African savannah elephants (Loxodonta africana) are most effective at making decisions crucial to herd survival, and old post-reproductive female resident killer whales (Orcinus orca) lead collective movements in hunting grounds. In contrast, little is known about the role of older males as leaders in long-lived social species. By analysing leadership patterns of all-male African savannah elephant traveling groups along elephant pathways in Makgadikgadi Pans National Park, Botswana, we found that the oldest males were more likely to lead collective movements. Our results challenge the assumption that older male elephants are redundant in the population and raise concerns over the biased removal of old bulls that currently occurs in both legal trophy hunting and illegal poaching. Selective harvesting of older males could have detrimental effects on the wider elephant society through loss of leaders crucial to younger male navigation in unknown, risky environments.
Collapse
Affiliation(s)
- Connie R B Allen
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QG, UK.
| | - Lauren J N Brent
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QG, UK
| | - Thatayaone Motsentwa
- Elephants for Africa, 5 Balfour Road, London, N5 2HB, UK.,Elephants for Africa, Mailbox 148 HAK, Maun, Botswana
| | - Michael N Weiss
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QG, UK
| | - Darren P Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QG, UK
| |
Collapse
|
27
|
Strongylid infection varies with age, sex, movement and social factors in wild African elephants. Parasitology 2020; 147:348-359. [PMID: 31840634 DOI: 10.1017/s0031182019001653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Comparing parasitic infection among individuals of wildlife populations can provide insight into factors that influence wildlife disease ecology. Strongylids are parasitic worms that infect the intestinal tract of vertebrates, and infection with strongylids can be approximated by counting strongylid eggs in dung samples. Here we tested for correlations between strongylid egg counts and 18 different individual characteristics, environmental and social factors in individually known wild African elephants. We counted more eggs in the dung samples of younger elephants and females relative to mature elephants and males. We also found that elephants spending more time outside reserves shed more strongylid eggs than elephants that were more often within reserves. Elephants that were less socially integrated, as measured by how much aggression they received from other elephants, shed fewer strongylid eggs; relatedly, socially isolated orphan elephants that had left their family shed fewer strongylid eggs than elephants that remained with their family. Our results suggest that landscapes altered by livestock grazing and social disruption caused by humans may impact parasitic infection in wildlife.
Collapse
|
28
|
Goldenberg SZ, Douglas-Hamilton I, Wittemyer G. Inter-generational change in African elephant range use is associated with poaching risk, primary productivity and adult mortality. Proc Biol Sci 2019; 285:rspb.2018.0286. [PMID: 29794044 DOI: 10.1098/rspb.2018.0286] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/25/2018] [Indexed: 11/12/2022] Open
Abstract
Repeated use of the same areas may benefit animals as they exploit familiar sites, leading to consistent home ranges over time that can span generations. Changing risk landscapes may reduce benefits associated with home range fidelity, however, and philopatric animals may alter movement in response to new pressures. Despite the importance of range changes to ecological and evolutionary processes, little tracking data have been collected over the long-term nor has range change been recorded in response to human pressures across generations. Here, we investigate the relationships between ecological, demographic and human variables and elephant ranging behaviour across generations using 16 years of tracking data from nine distinct female social groups in a population of elephants in northern Kenya that was heavily affected by ivory poaching during the latter half of the study. Nearly all groups-including those that did not experience loss of mature adults-exhibited a shift north over time, apparently in response to increased poaching in the southern extent of the study area. However, loss of mature adults appeared to be the primary indicator of range shifts and expansions, as generational turnover was a significant predictor of range size increases and range centroid shifts. Range expansions and northward shifts were associated with higher primary productivity and lower poached carcass densities, while westward shifts exhibited a trend to areas with higher values of primary productivity and higher poached carcass densities relative to former ranges. Together these results suggest a trade-off between resource access, mobility and safety. We discuss the relevance of these results to elephant conservation efforts and directions meriting further exploration in this disrupted society of a keystone species.
Collapse
Affiliation(s)
- Shifra Z Goldenberg
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA .,Save the Elephants, Nairobi 00200, Kenya
| | - Iain Douglas-Hamilton
- Save the Elephants, Nairobi 00200, Kenya.,Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - George Wittemyer
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA.,Save the Elephants, Nairobi 00200, Kenya
| |
Collapse
|
29
|
Symons J, Sprogis KR, Bejder L. Implications of survey effort on estimating demographic parameters of a long-lived marine top predator. Ecol Evol 2018; 8:10470-10481. [PMID: 30464819 PMCID: PMC6238146 DOI: 10.1002/ece3.4512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 03/19/2018] [Accepted: 03/29/2018] [Indexed: 12/30/2022] Open
Abstract
Effective management of wildlife populations rely on knowledge of their abundance, survival, and reproductive rates. Maintaining long‐term studies capable of estimating demographic parameters for long‐lived, slow‐reproducing species is challenging. Insights into the effects of research intensity on the statistical power to estimate demographic parameters are limited. Here, we investigate implications of survey effort on estimating abundance, home range sizes, and reproductive output of Indo‐Pacific bottlenose dolphins (Tursiops aduncus), using a 3‐year subsample of a long‐term, capture–recapture study off Bunbury, Western Australia. Photo‐identification on individual dolphins was collected following Pollock's Robust Design, where seasons were defined as “primary periods”, each consisting of multiple “secondary periods.” The full dataset consisted of 12 primary periods and 72 secondary periods, resulting in the study area being surveyed 24 times/year. We simulated reduced survey effort by randomly removing one, two, or three secondary periods per primary period. Capture–recapture models were used to assess the effect of survey intensity on the power to detect trends in population abundance, while individual dolphin sighting histories were used to assess the ability to conduct home range analyses. We used sighting records of adult females and their calving histories to assess survey effort on quantifying reproductive output. A 50% reduction in survey effort resulted in (a) up to a 36% decline in population abundance at the time of detection; (b) a reduced ability to estimate home range sizes, by increasing the time for individuals to be sighted on ≥30 occasions (an often‐used metric for home range analyses) from 7.74 to 14.32 years; and (c) 33%, 24%, and 33% of annual calving events across three years going undocumented, respectively. Results clearly illustrate the importance of survey effort on the ability to assess demographic parameters with clear implications for population viability analyses, population forecasting, and conservation efforts to manage human–wildlife interactions.
Collapse
Affiliation(s)
- John Symons
- Cetacean Research Unit School of Veterinary and Life Sciences Murdoch University Murdoch Western Australia Australia
| | - Kate R Sprogis
- Cetacean Research Unit School of Veterinary and Life Sciences Murdoch University Murdoch Western Australia Australia.,Zoophysiology Department of Bioscience Aarhus University Aarhus Denmark
| | - Lars Bejder
- Cetacean Research Unit School of Veterinary and Life Sciences Murdoch University Murdoch Western Australia Australia.,Marine Mammal Research Program Hawaii Institute of Marine Biology University of Hawaii at Manoa Honolulu Hawaii
| |
Collapse
|
30
|
Elephant Crop Damage: Subsistence Farmers’ Social Vulnerability, Livelihood Sustainability and Elephant Conservation. SUSTAINABILITY 2018. [DOI: 10.3390/su10103572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
African elephants (Loxodonta africana) induce considerable crop damage risks, shocks and stresses on subsistence farmers at the wildlife-agriculture interface. In this study, we explored the social dimensions of human-elephant interactions in the wildlife-agrarian landscape. The study aimed at unraveling the associated hazardous conditions and nature of the subsistence farmers’ social vulnerability and practices with respect to elephant crop damage, subsistence farmers’ livelihoods, and elephant conservation. Applying qualitative thematic content analysis, the sustainable livelihood framework (SLF) and additive generalized linear models (GLMs), this study revealed that the status of relational social capital influences human-elephant conflict (HEC) management and subsistence farmers’ responses, regardless of the farmers’ social learning and environmental values about the social-ecological system. The strengthening of multiple local stakeholder participation, institutional governance and access to livelihoods assets are needed for human food security and elephant conservation. Adoption of more effective nuanced crop protection counter-measures against elephants at farm level is urgently needed.
Collapse
|
31
|
|
32
|
Abstract
AbstractWith an increase in poaching of elephants Loxodonta africana across Africa, it is vital to know exactly how many elephants remain and where they occur, to ensure that protection and management are planned appropriately. From a nationwide survey we provide current population and distribution data for elephants in South Africa. We consider the viability of elephant populations in the country, as well as some of the management techniques implemented and how effective these are in controlling elephant numbers. According to our surveys there were 28,168 elephants in South Africa as of December 2015, with 78% of these occurring in Kruger National Park and reserves bordering and open to the Park. Of the country's 78 discrete reserves that host elephants, 77% have populations of < 100 elephants, which could mean they are not genetically viable. We discuss our findings in terms of the conservation value of South Africa's elephant reserves, and the animal welfare implications. We recommend that the fragmentation of elephant habitat in the country be addressed through a national elephant management strategy that promotes wildlife corridors between existing, neighbouring elephant reserves.
Collapse
|
33
|
Bastille-Rousseau G, Wall J, Douglas-Hamilton I, Wittemyer G. Optimizing the positioning of wildlife crossing structures using GPS telemetry. J Appl Ecol 2018. [DOI: 10.1111/1365-2664.13117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guillaume Bastille-Rousseau
- Department of Fish, Wildlife, and Conservation Biology; Colorado State University; Fort Collins CO USA
- Save the Elephants; Nairobi Kenya
| | | | | | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology; Colorado State University; Fort Collins CO USA
- Save the Elephants; Nairobi Kenya
| |
Collapse
|
34
|
Turkalo AK, Wrege PH, Wittemyer G. Demography of a forest elephant population. PLoS One 2018; 13:e0192777. [PMID: 29447207 PMCID: PMC5813957 DOI: 10.1371/journal.pone.0192777] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/30/2018] [Indexed: 11/18/2022] Open
Abstract
African forest elephants face severe threats from illegal killing for ivory and bushmeat and habitat conversion. Due to their cryptic nature and inaccessible range, little information on the biology of this species has been collected despite its iconic status. Compiling individual based monitoring data collected over 20 years from the Dzanga Bai population in Central African Republic, we summarize sex and age specific survivorship and female age specific fecundity for a cohort of 1625 individually identified elephants. Annual mortality (average = 3.5%) and natality (average = 5.3%) were lower and markedly less variable relative to rates reported for savanna elephant populations. New individuals consistently entered the study system, leading to a 2.5% average annual increase in the registered population. Calf sex ratios among known birth did not differ from parity. A weak seasonal signal in births was detected suggesting increased conceptions during the wet season. Inter-calf intervals and age of primiparity were longer relative to savanna elephant populations. Within the population, females between the ages of 25-39 demonstrated the shortest inter-calf intervals and highest fecundity, and previous calf sex had no influence on the interval. Calf survivorship was high (97%) the first two years after birth and did not differ by sex. Male and female survival began to differ by the age of 13 years, and males demonstrated significantly lower survival relative to females by the age of 20. It is suspected these differences are driven by human selection for ivory. Forest elephants were found to have one of the longest generation times recorded for any species at 31 years. These data provide fundamental understanding of forest elephant demography, providing baseline data for projecting population status and trends.
Collapse
Affiliation(s)
- Andrea K. Turkalo
- The Wildlife Conservation Society, B.P., Bangui, Central African Republic
- The Elephant Listening Project, Bioacoustics Research Program, Cornell Lab of Ornithology, Ithaca, New York, United States of America
| | - Peter H. Wrege
- The Elephant Listening Project, Bioacoustics Research Program, Cornell Lab of Ornithology, Ithaca, New York, United States of America
| | - George Wittemyer
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, Colorado, United States of America
- Save The Elephants, Nairobi, Kenya
- * E-mail:
| |
Collapse
|
35
|
Hunninck L, Ringstad IH, Jackson CR, May R, Fossøy F, Uiseb K, Killian W, Palme R, Røskaft E. Being stressed outside the park-conservation of African elephants ( Loxodonta africana) in Namibia. CONSERVATION PHYSIOLOGY 2017; 5:cox067. [PMID: 29270294 PMCID: PMC5734242 DOI: 10.1093/conphys/cox067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/27/2017] [Accepted: 11/06/2017] [Indexed: 05/30/2023]
Abstract
The conservation of the African savanna elephant (Loxodonta africana) is of prime importance for many African countries. Interactions between elephants and humans are known to induce stress and thereby have the potential to affect elephants' fitness. In Namibia, anthropogenic disturbances are increasing due to increasing human population size and development, particularly near protected areas, such as national parks. In this study, we investigated elephant stress levels in relation to their land use, specifically their protection status, comparing elephants within Etosha National Park in Namibia with elephants residing outside the park. We noninvasively collected dung samples of 91 elephants and determined the concentration of faecal glucocorticoid metabolites (fGCM), an indicator of physiological stress. Elephants outside the park (N = 35) had significantly higher concentrations of fGCM than those inside ENP (N = 56), suggesting that, despite including community-based conservancies, unprotected areas are more stressful for elephants than protected areas, most likely due to increased interactions with humans. We also found that males had lower fGCM concentrations than females, but no significant effect of age, body size or group size was detected. Additionally, herd sizes were significantly smaller and calf recruitment was potentially lower in unprotected areas. These findings underpin the importance of protected areas such as ENP, while encouraging decision-makers to continue reducing and mitigating potential human-induced disturbances.
Collapse
Affiliation(s)
- Louis Hunninck
- Norwegian University of Science and Technology—NTNU, Department of Biology, Høgskoleringen 1, 7491 Trondheim, Norway
| | - Iris H Ringstad
- Norwegian University of Science and Technology—NTNU, Department of Biology, Høgskoleringen 1, 7491 Trondheim, Norway
| | - Craig R Jackson
- Norwegian Institute for Nature Research—NINA, Department of Terrestrial Ecology, Høgskoleringen 9, 7034 Trondheim, Norway
| | - Roel May
- Norwegian Institute for Nature Research—NINA, Department of Terrestrial Ecology, Høgskoleringen 9, 7034 Trondheim, Norway
| | - Frode Fossøy
- Norwegian University of Science and Technology—NTNU, Department of Biology, Høgskoleringen 1, 7491 Trondheim, Norway
- Norwegian Institute for Nature Research—NINA, Department of Terrestrial Ecology, Høgskoleringen 9, 7034 Trondheim, Norway
| | - Kenneth Uiseb
- Ministry of Environment and Tourism, Directorate of Scientific Services, P/Bag 13306, Windhoek, Namibia
| | - Werner Killian
- Ministry of Environment and Tourism, Directorate of Scientific Services, P/Bag 13306, Windhoek, Namibia
| | - Rupert Palme
- University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Eivin Røskaft
- Norwegian University of Science and Technology—NTNU, Department of Biology, Høgskoleringen 1, 7491 Trondheim, Norway
| |
Collapse
|
36
|
Goldenberg SZ, Wittemyer G. Orphaned female elephant social bonds reflect lack of access to mature adults. Sci Rep 2017; 7:14408. [PMID: 29089603 PMCID: PMC5663962 DOI: 10.1038/s41598-017-14712-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/13/2017] [Indexed: 11/09/2022] Open
Abstract
Compensatory social behavior in nonhuman animals following maternal loss has been documented, but understanding of how orphans allocate bonding to reconstruct their social networks is limited. Successful social integration may be critical to survival and reproduction for highly social species and, therefore, may be tied to population persistence. We examined the social partners involved in affiliative interactions of female orphans and non-orphans in an elephant population in Samburu, northern Kenya that experienced heightened adult mortality driven by drought and intense ivory poaching. We contrasted partners across different competitive contexts to gain insight to the influence of resource availability on social interactions. Though the number of partners did not differ between orphans and non-orphans, their types of social partners did. Orphans interacted with sisters and matriarchs less while feeding than did non-orphans, but otherwise their affiliates were similar. While resting under spatially concentrated shade, orphans had markedly less access to mature adults but affiliated instead with sisters, bulls, and age mates. Orphan propensity to strengthen bonds with non-dominant animals appears to offer routes to social integration following maternal loss, but lack of interaction with adult females suggests orphans may experience decreased resource access and associated fitness costs in this matriarchal society.
Collapse
Affiliation(s)
- Shifra Z Goldenberg
- Department of Fish, Wildlife, and Conservation Biology, Fort Collins, CO, 80523, USA.
- Save the Elephants, Nairobi, 00200, Kenya.
| | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology, Fort Collins, CO, 80523, USA
- Save the Elephants, Nairobi, 00200, Kenya
| |
Collapse
|
37
|
Fritz H. Long-term field studies of elephants: understanding the ecology and conservation of a long-lived ecosystem engineer. J Mammal 2017. [DOI: 10.1093/jmammal/gyx023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
38
|
A clear and present danger: impacts of poisoning on a vulture population and the effect of poison response activities. ORYX 2017. [DOI: 10.1017/s0030605316001137] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractVultures in Africa are being poisoned deliberately by poachers to prevent the birds alerting authorities to the poachers’ illegal activities, or for harvesting and sale of body parts for use in witchcraft. Hundreds of vultures can be killed at a single poisoned elephant Loxodonta africana carcass, and although field staff trained in poison response activities can limit the damage, mortalities remain numerous. We used the population viability analysis programme VORTEX to simulate seven 100-year-long scenarios investigating various rates of poisoning mortalities and the remedial effects of poison response activities on a population of Critically Endangered white-backed vultures Gyps africanus breeding in Kruger National Park, South Africa. In six scenarios the population declined (λ < 1); in three scenarios the population remained extant over the 100-year simulations but declined by 60–90% from a starting size of 2,400 individuals. In two scenarios one poisoned elephant carcass left untreated and causing the greatest number of vulture deaths was modelled as a catastrophic event with a 50% probability of annual occurrence, which resulted in a 100% probability of population extinction, with a mean time to extinction of 55–62 years. Effective poison response activities were modelled as a 70% reduction of mortality at each poisoned elephant carcass and resulted in population persistence after 100 years but with a c. 90% reduction in size (final n = 205). We highlight that although poison response activities will not prevent poisoning from occurring, they form an essential part of wider conservation actions designed to prevent local extinctions of vultures or other vulnerable species.
Collapse
|
39
|
Zacarias D, Bini LM, Loyola R. Systematic review on the conservation genetics of African savannah elephants. PeerJ 2016; 4:e2567. [PMID: 27781165 PMCID: PMC5075695 DOI: 10.7717/peerj.2567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/14/2016] [Indexed: 11/20/2022] Open
Abstract
Background In this paper we review the conservation genetics of African savannah elephants, aiming to understand the spatio-temporal research trends and their underlying factors. As such, we explore three questions associated to the conservation genetics and molecular ecology of these elephants: (1) what are the research trends concerning the conservation genetics of Loxodonta africana? (2) Do richer countries conduct more research on the genetics of African elephants? (3) Which attributes influence where scholars conduct their research? Materials and Methods We examined available peer-reviewed publications from 1993 to 2014 in complementary online databases, including the ISI/Web of Science (WoS), Scopus and Google Scholar (GS), and searched for publications in scientific journals as well as in the reference section of these publications. We analyzed the annual trend of publications in this field of research, including the number of authors, levels of collaboration among authors, year of publication, publishing journal and the countries from where genetic samples were collected. Additionally, we identified main research clusters, authors, and institutional collaborations, based on co-citation and co-occurrence networks. Results We found that during the study period there was a positive trend in the number of publications and a reduction in the number of authors per paper. Twenty-five countries contributed, with the majority of publications authored by researchers in the USA, Kenya and South Africa. The majority of samples were collected in Kenya, Tanzania and South Africa. Research outputs are associated with the existence of long-term conservation/research projects and research potential as measured by the literacy rate and the number of higher education institutions in a country. Five research clusters were identified, focusing on the origin and evolution of the species, methodological issues and the relatedness among elephant species. Conclusions Research in this field should be expanded to additional countries harboring elephant populations to enable a more comprehensive understanding of the population structure and genetic differentiation of the species, and to cope with challenges associated with the conservation of the species such as illegal hunting, habitat fragmentation, species reintroduction and climate change.
Collapse
Affiliation(s)
- Daniel Zacarias
- Programa de Pós-graduação em Ecologia e Evolução, Universidade Federal de Goiás, Goiania, Goias, Brazil.,Programa de Pós-graduação Ciência para o Desenvolvimento (PGCD), Instituto Gulbenkian de Ciências, Lisboa, Portugal
| | - Luis Mauricio Bini
- Departamento de Ecologia, Universidade Federal de Goiás, Goiania, Goias, Brazil
| | - Rafael Loyola
- Departamento de Ecologia, Universidade Federal de Goiás, Goiania, Goias, Brazil
| |
Collapse
|
40
|
Goldenberg SZ, Douglas-Hamilton I, Daballen D, Wittemyer G. Challenges of using behavior to monitor anthropogenic impacts on wildlife: a case study on illegal killing of African elephants. Anim Conserv 2016. [DOI: 10.1111/acv.12309] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Z. Goldenberg
- Department of Fish, Wildlife, and Conservation Biology; Colorado State University; Fort Collins CO USA
- Graduate Degree Program in Ecology; Colorado State University; Fort Collins CO USA
- Save the Elephants; Nairobi Kenya
| | - I. Douglas-Hamilton
- Save the Elephants; Nairobi Kenya
- Department of Zoology; University of Oxford; Oxford UK
| | | | - G. Wittemyer
- Department of Fish, Wildlife, and Conservation Biology; Colorado State University; Fort Collins CO USA
- Graduate Degree Program in Ecology; Colorado State University; Fort Collins CO USA
- Save the Elephants; Nairobi Kenya
| |
Collapse
|
41
|
de Silva S, Schmid V, Wittemyer G. Fission–fusion processes weaken dominance networks of female Asian elephants in a productive habitat. Behav Ecol 2016. [DOI: 10.1093/beheco/arw153] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
42
|
Breuer T, Maisels F, Fishlock V. The consequences of poaching and anthropogenic change for forest elephants. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2016; 30:1019-1026. [PMID: 26801000 DOI: 10.1111/cobi.12679] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 01/17/2016] [Indexed: 06/05/2023]
Abstract
Poaching has devastated forest elephant populations (Loxodonta cyclotis), and their habitat is dramatically changing. The long-term effects of poaching and other anthropogenic threats have been well studied in savannah elephants (Loxodonta africana), but the impacts of these changes for Central Africa's forest elephants have not been discussed. We examined potential repercussions of these threats and the related consequences for forest elephants in Central Africa by summarizing the lessons learned from savannah elephants and small forest elephant populations in West Africa. Forest elephant social organization is less known than the social organization of savannah elephants, but the close evolutionary history of these species suggests that they will respond to anthropogenic threats in broadly similar ways. The loss of older, experienced individuals in an elephant population disrupts ecological, social, and population parameters. Severe reduction of elephant abundance within Central Africa's forests can alter plant communities and ecosystem functions. Poaching, habitat alterations, and human population increase are probably compressing forest elephants into protected areas and increasing human-elephant conflict, which negatively affects their conservation. We encourage conservationists to look beyond documenting forest elephant population decline and address the causes of these declines when developing conversation strategies. We suggest assessing the effectiveness of the existing protected-area networks for landscape connectivity in light of current industrial and infrastructure development. Longitudinal assessments of the effects of landscape changes on forest elephant sociality and behavior are also needed. Finally, lessons learned from West African elephant population loss and habitat fragmentation should be used to inform strategies for land-use planning and managing human-elephant interactions.
Collapse
Affiliation(s)
- Thomas Breuer
- Global Conservation Program, Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York, 10460, U.S.A..
| | - Fiona Maisels
- Global Conservation Program, Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York, 10460, U.S.A
- School of Natural Sciences, University of Stirling, FK9 4LA, Scotland, United Kingdom
| | - Vicki Fishlock
- School of Natural Sciences, University of Stirling, FK9 4LA, Scotland, United Kingdom
- Amboseli Trust for Elephants, Langata 00509, Nairobi, P.O. Box 15135, Kenya
| |
Collapse
|
43
|
Turkalo AK, Wrege PH, Wittemyer G. Slow intrinsic growth rate in forest elephants indicates recovery from poaching will require decades. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12764] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrea K. Turkalo
- The Wildlife Conservation Society; B.P. 1053 Bangui Central African Republic
- The Elephant Listening Project; Bioacoustics Research Program; Cornell Lab of Ornithology; Ithaca NY USA
| | - Peter H. Wrege
- The Elephant Listening Project; Bioacoustics Research Program; Cornell Lab of Ornithology; Ithaca NY USA
| | - George Wittemyer
- Department of Fish, Wildlife and Conservation Biology; Colorado State University; Fort Collins CO USA
- Save The Elephants; PO Box 54667 Nairobi Kenya
| |
Collapse
|
44
|
Soltis J, King L, Vollrath F, Douglas-Hamilton I. Accelerometers and simple algorithms identify activity budgets and body orientation in African elephants Loxodonta africana. ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
45
|
Goldenberg SZ, Oduor S, Kinnaird MF, Daballen D, Douglas‐Hamilton I, Wittemyer G. Evidence of strong spatial segregation between elephant subpopulations in the contiguous Laikipia–Samburu ecosystem in Kenya. Afr J Ecol 2016. [DOI: 10.1111/aje.12310] [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)
- Shifra Z. Goldenberg
- Department of Fish Wildlife, and Conservation Biology Colorado State University Fort Collins CO 80523U.S.A
- Graduate Degree Program in Ecology Colorado State University Fort Collins CO 80523 U.S.A
- Save the Elephants P.O. Box 54667 Nairobi 00200 Kenya
| | - Sandy Oduor
- Mpala Research Centre P.O. Box 555 Nanyuki 10400 Kenya
| | - Margaret F. Kinnaird
- Mpala Research Centre P.O. Box 555 Nanyuki 10400 Kenya
- Wildlife Conservation Society Global Conservation Programs Bronx NY 10460 U.S.A
| | | | - Iain Douglas‐Hamilton
- Save the Elephants P.O. Box 54667 Nairobi 00200 Kenya
- Department of Zoology University of Oxford Oxford OX1 3PS U.K
| | - George Wittemyer
- Department of Fish Wildlife, and Conservation Biology Colorado State University Fort Collins CO 80523U.S.A
- Graduate Degree Program in Ecology Colorado State University Fort Collins CO 80523 U.S.A
- Save the Elephants P.O. Box 54667 Nairobi 00200 Kenya
| |
Collapse
|
46
|
|
47
|
Onyango PO, Lesowapir B. Demography of a population with a long history of poaching and the utility of the individual identification technique as a tool for monitoring intermittently studied elephant populations. Afr J Ecol 2016. [DOI: 10.1111/aje.12297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Patrick O. Onyango
- Department of Zoology; Maseno University; PO Box 333-40105 Maseno Kenya
- Save the Elephants; PO Box 54667 Nairobi Kenya
| | | |
Collapse
|
48
|
Goldenberg SZ, Douglas-Hamilton I, Wittemyer G. Vertical Transmission of Social Roles Drives Resilience to Poaching in Elephant Networks. Curr Biol 2015; 26:75-9. [PMID: 26711491 DOI: 10.1016/j.cub.2015.11.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 10/15/2015] [Accepted: 11/03/2015] [Indexed: 10/22/2022]
Abstract
Network resilience to perturbation is fundamental to functionality in systems ranging from synthetic communication networks to evolved social organization [1]. While theoretical work offers insight into causes of network robustness, examination of natural networks can identify evolved mechanisms of resilience and how they are related to the selective pressures driving structure. Female African elephants (Loxodonta africana) exhibit complex social networks with node heterogeneity in which older individuals serve as connectivity hubs [2, 3]. Recent ivory poaching targeting older elephants in a well-studied population has mirrored the targeted removal of highly connected nodes in the theoretical literature that leads to structural collapse [4, 5]. Here we tested the response of this natural network to selective knockouts. We find that the hierarchical network topology characteristic of elephant societies was highly conserved across the 16-year study despite ∼70% turnover in individual composition of the population. At a population level, the oldest available individuals persisted to fill socially central positions in the network. For analyses using known mother-daughter pairs, social positions of daughters during the disrupted period were predicted by those of their mothers in years prior, were unrelated to individual histories of family mortality, and were actively built. As such, daughters replicated the social network roles of their mothers, driving the observed network resilience. Our study provides a rare bridge between network theory and an evolved system, demonstrating social redundancy to be the mechanism by which resilience to perturbation occurred in this socially advanced species.
Collapse
Affiliation(s)
- Shifra Z Goldenberg
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA; Save the Elephants, Nairobi 00200, Kenya.
| | - Iain Douglas-Hamilton
- Save the Elephants, Nairobi 00200, Kenya; Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA; Save the Elephants, Nairobi 00200, Kenya
| |
Collapse
|
49
|
Abstract
Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator-prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.
Collapse
|
50
|
Using Poaching Levels and Elephant Distribution to Assess the Conservation Efficacy of Private, Communal and Government Land in Northern Kenya. PLoS One 2015; 10:e0139079. [PMID: 26407001 PMCID: PMC4583284 DOI: 10.1371/journal.pone.0139079] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 09/09/2015] [Indexed: 11/19/2022] Open
Abstract
Efforts to curb elephant poaching have focused on reducing demand, confiscating ivory and boosting security patrols in elephant range. Where land is under multiple uses and ownership, determining the local poaching dynamics is important for identifying successful conservation models. Using 2,403 verified elephant, Loxodonta africana, mortality records collected from 2002 to 2012 and the results of aerial total counts of elephants conducted in 2002, 2008 and 2012 for the Laikipia-Samburu ecosystem of northern Kenya, we sought to determine the influence of land ownership and use on diurnal elephant distribution and on poaching levels. We show that the annual proportions of illegally killed (i.e., poached) elephants increased over the 11 years of the study, peaking at 70% of all recorded deaths in 2012. The type of land use was more strongly related to levels of poaching than was the type of ownership. Private ranches, comprising only 13% of land area, hosted almost half of the elephant population and had significantly lower levels of poaching than other land use types except for the officially designated national reserves (covering only 1.6% of elephant range in the ecosystem). Communal grazing lands hosted significantly fewer elephants than expected, but community areas set aside for wildlife demonstrated significantly higher numbers of elephants and lower illegal killing levels relative to non-designated community lands. While private lands had lower illegal killing levels than community conservancies, the success of the latter relative to other community-held lands shows the importance of this model of land use for conservation. This work highlights the relationship between illegal killing and various land ownership and use models, which can help focus anti-poaching activities.
Collapse
|