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Newediuk L, Mastromonaco GF, Vander Wal E. Associations between glucocorticoids and habitat selection reflect daily and seasonal energy requirements. MOVEMENT ECOLOGY 2024; 12:30. [PMID: 38649956 PMCID: PMC11036748 DOI: 10.1186/s40462-024-00475-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 04/14/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Glucocorticoids are often associated with stressful environments, but they are also thought to drive the best strategies to improve fitness in stressful environments. Glucocorticoids improve fitness in part by regulating foraging behaviours in response to daily and seasonal energy requirements. However, many studies demonstrating relationships between foraging behaviour and glucocorticoids are experimental, and few observational studies conducted under natural conditions have tested whether changing glucocorticoid levels are related to daily and seasonal changes in energy requirements. METHODS We integrated glucocorticoids into habitat selection models to test for relationships between foraging behaviour and glucocorticoid levels in elk (Cervus canadensis) as their daily and seasonal energy requirements changed. Using integrated step selection analysis, we tested whether elevated glucocorticoid levels were related to foraging habitat selection on a daily scale and whether that relationship became stronger during lactation, one of the greatest seasonal periods of energy requirement for female mammals. RESULTS We found stronger selection of foraging habitat by female elk with elevated glucocorticoids (eß = 1.44 95% CI 1.01, 2.04). We found no difference in overall glucocorticoid levels after calving, nor a significant change in the relationship between glucocorticoids and foraging habitat selection at the time of calving. However, we found a gradual increase in the relationship between glucocorticoids and habitat selection by female elk as their calves grew over the next few months (eß = 1.01, 95% CI 1.00, 1.02), suggesting a potentially stronger physiological effect of glucocorticoids for elk with increasing energy requirements. CONCLUSIONS We suggest glucocorticoid-integrated habitat selection models demonstrate the role of glucocorticoids in regulating foraging responses to daily and seasonal energy requirements. Ultimately, this integration will help elucidate the implications of elevated glucocorticoids under natural conditions.
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Affiliation(s)
- Levi Newediuk
- Department of Biology, Memorial University, St. John's Newfoundland, A1B 3X9, Canada.
- Current address: Biological Sciences Department, University of Manitoba, Winnipeg Manitoba, R3T 2N2, Canada.
| | | | - Eric Vander Wal
- Department of Biology, Memorial University, St. John's Newfoundland, A1B 3X9, Canada
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Szydlowski M. Wicked Problems, Novel Solutions: Nepalese Elephant Tourism and Conservation. Animals (Basel) 2024; 14:171. [PMID: 38200902 PMCID: PMC10777960 DOI: 10.3390/ani14010171] [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: 11/10/2023] [Revised: 12/19/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024] Open
Abstract
Endangered Asian elephants (Elephas maximus) find themselves at the center of debates involving politics, land use, human-wildlife conflict, and environmental justice. The intensity of such debates has led scholars to label conservation challenges as wicked problems with profound implications on local and global practice. In elephant range states such as Nepal, these debates are made more complex through human 'ownership' of endangered individuals for use in tourism, worship, or co-work. Human perspectives on the ethics of using animals for tourism are changing, even in areas heavily reliant on the tourism industry for survival. These debates become inflamed when non-residents take on adversarial positions despite an acceptance of the 'ownership' or 'use' of endangered individuals among local communities. Novel approaches are needed if there is any hope of establishing a common ground upon which to build relationships which may benefit community members, international interests, and endangered individuals.
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Robertson MR, Olivier LJ, Roberts J, Yonthantham L, Banda C, N’gombwa IB, Dale R, Tiller LN. Testing the Effectiveness of the "Smelly" Elephant Repellent in Controlled Experiments in Semi-Captive Asian and African Savanna Elephants. Animals (Basel) 2023; 13:3334. [PMID: 37958089 PMCID: PMC10647569 DOI: 10.3390/ani13213334] [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: 08/31/2023] [Revised: 10/12/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
Crop-raiding by elephants is one of the most prevalent forms of human-elephant conflict and is increasing with the spread of agriculture into wildlife range areas. As the magnitude of conflicts between people and elephants increases across Africa and Asia, mitigating and reducing the impacts of elephant crop-raiding has become a major focus of conservation intervention. In this study, we tested the responses of semi-captive elephants to the "smelly" elephant repellent, a novel olfactory crop-raiding mitigation method. At two trial sites, in Zambia and Thailand, African elephants (Loxodonta africana) and Asian elephants (Elephas maximus) were exposed to the repellent, in order to test whether or not they entered an area protected by the repellent and whether they ate the food provided. The repellent elicited clear reactions from both study groups of elephants compared to control conditions. Generalised linear models revealed that the elephants were more alert, sniffed more, and vocalised more when they encountered the repellent. Although the repellent triggered a response, it did not prevent elephants from entering plots protected by the repellent or from eating crops, unlike in trials conducted with wild elephants. Personality played a role in responses towards the repellent, as the elephants that entered the experimental plots were bolder and more curious individuals. We conclude that, although captive environments provide controlled settings for experimental testing, the ecological validity of testing human-elephant conflict mitigation methods with captive wildlife should be strongly considered. This study also shows that understanding animal behaviour is essential for improving human-elephant coexistence and for designing deterrence mechanisms. Appreciating personality traits in elephants, especially amongst "problem" elephants who have a greater propensity to crop raid, could lead to the design of new mitigation methods designed to target these individuals.
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Affiliation(s)
| | - Lisa J. Olivier
- Game Rangers International, Plot 2374, The Village, Leopards Hill Road, Lusaka 10101, Zambia; (L.J.O.); (C.B.)
| | - John Roberts
- Golden Triangle Asian Elephant Foundation, 229 Moo 1, Chiang Saen, Chiang Rai 57150, Thailand; (J.R.); (L.Y.)
| | - Laddawan Yonthantham
- Golden Triangle Asian Elephant Foundation, 229 Moo 1, Chiang Saen, Chiang Rai 57150, Thailand; (J.R.); (L.Y.)
| | - Constance Banda
- Game Rangers International, Plot 2374, The Village, Leopards Hill Road, Lusaka 10101, Zambia; (L.J.O.); (C.B.)
| | - Innocent B. N’gombwa
- Department of National Parks and Wildlife, Ministry of Tourism, Chilanga 10101, Zambia;
| | - Rachel Dale
- Department for Psychosomatic Medicine and Psychotherapy, University for Continuing Education Krems, 3500 Krems an der Donau, Austria;
| | - Lydia N. Tiller
- Amboseli Trust for Elephants, Langata, Nairobi 15135, Kenya;
- Durrell Institute of Conservation and Ecology, University of Kent, Canterbury CT2 7NZ, UK
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Li X, Chen J, Zhang C, Zhang S, Shen Q, Wang B, Bao M, Xu B, Wu Q, Han N, Huang Z. Fecal Metagenomics Study Reveals That a Low-Fiber Diet Drives the Migration of Wild Asian Elephants in Xishuangbanna, China. Animals (Basel) 2023; 13:3193. [PMID: 37893918 PMCID: PMC10603651 DOI: 10.3390/ani13203193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/30/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
The rare northward migration of wild Asian elephants in Xishuangbanna, China, has attracted global attention. Elephant migration is a complex ecological process, and the factors driving this long-distance migration remain elusive. In this study, fresh fecal samples were collected from both captive and wild Asian elephants, along with breastfed calves residing within the Wild Elephant Valley of Xishuangbanna. Our aim was to investigate the relationship between diet, gut microbiota, and migration patterns in Asian elephants through comprehensive metagenomic sequencing analyses. Among the breastfed Asian elephant group, Bacteroidales and Escherichia emerged as the dominant bacterial taxa, while the primary carbohydrate-active enzymes (CAZymes) enriched in this group were GH2, GH20, GH92, GH97, GH38, GH23, and GH43, aligning with their dietary source, namely breast milk. The bacterial taxa enriched in captive Asian elephants (CAEs) were mainly Butyrivibrio, Treponema, and Fibrobacter, and the enriched lignocellulose-degrading enzymes mainly included GH25, GH10, GH9, and cellulase (EC 3.2.1.4). These findings are consistent with the high-fiber diet of captive elephants. In contrast, the main bacterial taxa enriched in wild Asian elephants (WAEs) were Ruminococcus and Eubacterium, and the enriched CAZymes included GH109, GH20, GH33, GH28, GH106, and GH39. The abundance of lignocellulose-degrading bacteria and CAZyme content was low in WAEs, indicating challenges in processing high-fiber foods and explaining the low-fiber diet in this group. These findings suggest that wild elephant herds migrate in search of nutritionally suitable, low-fiber food sources.
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Affiliation(s)
- Xia Li
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
- Southwest United Graduate School, Kunming 650092, China
| | - Junmin Chen
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
- Key Laboratory of Yunnan Provincial Education Department for Plateau Characteristic Food Enzymes, Yunnan Normal University, Kunming 650500, China
| | - Chengbo Zhang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
| | - Shuyin Zhang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
| | - Qingzhong Shen
- Xishuangbanna National Nature Reserve Management and Protection Bureau, Jinghong 666100, China
| | - Bin Wang
- Xishuangbanna National Nature Reserve Management and Protection Bureau, Jinghong 666100, China
| | - Mingwei Bao
- Asian Elephant Provenance Breeding and Rescue Center in Xishuangbanna, Jinghong 666100, China
| | - Bo Xu
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
| | - Qian Wu
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
| | - Nanyu Han
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
| | - Zunxi Huang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, School of Life Sciences, Yunnan Normal University, Kunming 650500, China
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Lacomme L, Guerbois C, Fritz H, Ganswindt A, Rey B. Validation of a field-friendly faeces drying and storage method for quantifying faecal glucocorticoid metabolites in African elephants (Loxodonta africana) opens up new perspectives for conservationists. CONSERVATION PHYSIOLOGY 2023; 11:coad053. [PMID: 37538993 PMCID: PMC10395557 DOI: 10.1093/conphys/coad053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/15/2023] [Accepted: 07/24/2023] [Indexed: 08/05/2023]
Abstract
Faecal glucocorticoid metabolites (fGCMs) are a relevant means of non-invasively assessing adrenocortical activity and thus, a key physiological stress response in wildlife populations. However, the widespread use of fGCMs as a stress-related biomarker in conservation biology is often hampered by the logistical challenge of storing collected faecal material frozen until it reaches the laboratory for analysis. Although alternative approaches to minimize potential alteration of fGCM composition post-defecation have been recently identified, there is to our knowledge, no satisfactory alternative method established for the preservation of elephant dung. In this study, we validated a field-friendly protocol for dehydrating African elephant faeces samples using a food dehydrator with desiccant and investigated the stability of fGCM concentrations in the dehydrated faeces when stored at ambient temperature. We collected 40 faecal samples from African elephants and compared fGCM concentrations of freeze-dried and dehydrated sample sub-sets. Samples dried in the field showed a slight but significant overall -6% reduction in fGCM concentration compared with frozen control samples. However, fGCM concentrations following field dehydration protocol match those of control samples with high accuracy, as evidenced by the low bias and strong coefficient of determination between the two approaches (R2 = 0.88). In addition, over nearly 2 months, storage time at ambient temperature of the dehydrated samples had no effect on the fGCM concentrations compared with those measured in the control samples (F-statistic = 1.82; P = 0.18). Dehydrating the samples in the field thus provides an easy and cost-effective alternative to freezing, especially when working in remote areas with unstable electrical supply. Our results encourage the widespread use of fGCMs by conservationists as non-invasive means of steroid monitoring of African elephants in the current context of a general increase in wildlife welfare research. Future studies are needed to extend the use of this protocol to other species and to other steroid classes.
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Affiliation(s)
- Laura Lacomme
- Corresponding author: Biometry and Evolutionary Biology laboratory (LBBE), French National Centre for Scientific Research (CNRS), Unit 5558, University of Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex, France.
| | - Chloé Guerbois
- Sustainability Research Unit, Nelson Mandela University, George Campus, Madiba Drive, George 6529, South Africa
| | - Hervé Fritz
- Sustainability Research Unit, Nelson Mandela University, George Campus, Madiba Drive, George 6529, South Africa
| | - André Ganswindt
- Mammal Research Institute (MRI), Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Hatfield Campus, Pretoria 0028, South Africa
| | - Benjamin Rey
- Biometry and Evolutionary Biology laboratory (LBBE), French National Centre for Scientific Research (CNRS),Unit 5558, University of Lyon 1, 43 Bd du 11 novembre 1918, 69622 Villeurbanne cedex, France
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Corlatti L, Palme R, Valencak TG, Gomez KM. Season-dependent impact of forage quality on stress in alpine chamois. Ecol Evol 2023; 13:e10045. [PMID: 37139402 PMCID: PMC10150231 DOI: 10.1002/ece3.10045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/27/2023] [Accepted: 04/12/2023] [Indexed: 05/05/2023] Open
Abstract
Chronically heightened stress levels in wildlife species may have detrimental effects on individual life history traits, for example, through the increased likelihood of disease, parasitic infections, and overall reduced fitness. Understanding the drivers of stress may thus have great potential for informing wildlife conservation. Although the role of climate and individual status is well studied in stress ecology, the impact of related stressors such as dietary quality is of increasing interest to wildlife research and conservation. In this study, fecal cortisol metabolites (FCMs) in Alpine chamois Rupicapra r. rupicapra used as bioindicators of stress, and their relationship with forage quality-measured as the percentage of fecal crude protein (CP)-were investigated. Data collection took place in 2011 and 2012 in the Gran Paradiso National Park (Western Italian Alps), on 22 individually marked adult males. The relationship between FCMs and CPs was analyzed through linear models and separated between winter and summer months, accounting for the effect of potentially confounding exogenous and endogenous variables. After AICc-based model selection, we found that forage quality was negatively related to FCM levels in Alpine chamois during the summer months, meaning that higher quality forage was associated with the decreased expression of stress hormones. However, during the winter months, we did not find a significant relationship, potentially as a result of forage quality being ubiquitously poor. Although the mechanisms through which dietary variations impact FCM concentrations in wildlife populations are largely unknown, the occurrence of significant relationships between forage quality and stress levels supports potentially important implications for the long-term effect of climatic changes on the fitness of wildlife populations.
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Affiliation(s)
- Luca Corlatti
- Chair of Wildlife Ecology and ManagementUniversity of FreiburgFreiburgGermany
- Stelvio National Park – ERSAF LombardiaBormioItaly
| | - Rupert Palme
- Department of Biomedical SciencesUniversity of Veterinary MedicineViennaAustria
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LaDue CA, Hunt KE, Kiso WK, Freeman EW. Hormonal variation and temporal dynamics of musth in Asian elephants ( Elephas maximus) are associated with age, body condition and the social environment. CONSERVATION PHYSIOLOGY 2023; 11:coad019. [PMID: 38026805 PMCID: PMC10660383 DOI: 10.1093/conphys/coad019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 12/01/2023]
Abstract
The sustainability of endangered Asian elephants in human care is threatened in part by low breeding success and concerns over individual animal wellbeing. Male elephants have received less research attention compared to females, yet males deserve special consideration due to their unique reproductive biology (particularly the sexual state of "musth") and the complex interaction of physiological, environmental, and social pressures they face. We measured fecal androgen metabolites (FAMs), fecal glucocorticoid metabolites (FGMs), and fecal triiodothyronine metabolites (FT3s) collected weekly over approximately 12 months from 26 male Asian elephants housed in zoos across the US, hypothesizing that FAM, FGM, and FT3 concentrations would be associated with temporal correlates of musth and would vary further with intrinsic (musth status, age, body condition) and extrinsic (social environment) factors. The duration of each musth episode was positively associated with exposure to male conspecifics and negatively associated with body condition. Further, elevated FAM concentrations were associated with social exposure, age, and body condition, and FGM concentrations also varied with age and body condition. FT3 concentrations were not associated with any factor we measured. We also identified periods of lower FAM concentration than confirmed musth episodes (but still higher than baseline FAM concentrations) that we termed "elevated FAM episodes." The durations of these episodes were negatively correlated with exposure to other male elephants. Together, these results provide evidence that hormone profiles (including those that are predicted to change around musth) vary significantly between male Asian elephants in a way that may be attributed to intrinsic and extrinsic factors. Studies like these serve to enhance the sustainability of ex-situ populations by providing wildlife managers with information to enhance the health, welfare, and reproduction of threatened species like Asian elephants.
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Affiliation(s)
- Chase A LaDue
- Department of Environmental Science and Policy, 4400 University Drive, MSN 5F2, George Mason University, Fairfax, VA 22030, USA
- Oklahoma City Zoo and Botanical Garden, 2000 Remington Place, Oklahoma City, OK 73111, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, 10900 University Boulevard, Manassas, VA 20110, USA
- Smithsonian-Mason School of Conservation, 1500 Remount Road, Front Royal, VA 22630, USA
| | - Wendy K Kiso
- White Oak Conservation Foundation, 581705 White Oak Road, Yulee, FL 32097, USA
- Colossal Biosciences, 3309 Elm Street, Dallas, TX 75226, USA
| | - Elizabeth W Freeman
- School of Integrative Studies, 4400 University Drive, MSN 5D3, George Mason University, Fairfax, VA 22030, USA
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Hariohay KM, Hunninck L, Ranke PS, Fyumagwa RD, Palme R, Røskaft E. Between hunter and climate: the effects of hunting and environmental change on fecal glucocorticoid metabolite levels in two sympatric ungulate species in the Ruaha-Rungwa ecosystem, Tanzania. CONSERVATION PHYSIOLOGY 2023; 11:coad002. [PMID: 38026801 PMCID: PMC10660377 DOI: 10.1093/conphys/coad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 11/22/2022] [Accepted: 01/31/2023] [Indexed: 12/01/2023]
Abstract
Understanding the drivers of animal population decline is a key focus of conservation biologists. Anthropogenic activities such as hunting have long been established as potentially detrimental to a population's persistence. However, environmental perturbations such as increased temperature variability, exacerbated by climate change, can also have important effects on animal populations. Animals can respond to these challenges by adjusting both their behavior and physiology. We measured fecal glucocorticoid metabolites (FGMs) of common impala (Aepyceros melampus) and greater kudu (Tragelaphus strepsiceros), both currently in stable populations, to examine effects of hunting, forage availability, daily variability in temperature and group size on their physiological stress response. The study was conducted across two adjacent protected areas, (i) one non-hunted area (Ruaha National Park; RNP) and (ii) one area used for trophy hunting (Rungwa Game Reserve; RGR). Both impala and kudu had significantly higher FGM levels in the area that allows hunting, while FGM levels decreased with increasing forage availability and increasing daily temperature. Moreover, impala (but not kudu) had lower FGM levels with larger group sizes. Our results indicate that the management regime can significantly alter the physiological state of wild ungulate populations. We also highlight the importance of considering the combined effects of anthropogenic, environmental and social contexts when studying the stress response of wild populations. Our results emphasize the value of protected areas and continued monitoring of hunting quota in order to maintain ungulate populations that are less vulnerable to population declines.
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Affiliation(s)
- Kwaslema Malle Hariohay
- Department of Wildlife Management, College of African Wildlife Management, Mweka, P. O. Box 3031, Moshi, Tanzania
- Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491, Trondheim, Norway
| | - Louis Hunninck
- Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491, Trondheim, Norway
- Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Peter S Ranke
- Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491, Trondheim, Norway
- Center for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491, Trondheim, Norway
| | - Robert D Fyumagwa
- Department of Wildlife Management, Tanzania Wildlife Research Institute (TAWIRI), P.O. Box 661, Arusha
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna
| | - Eivin Røskaft
- Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491, Trondheim, Norway
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Das P, Kshettry A, Kumara HN. Trunk picking from a truncating menu: Dry season forage selection by Asian elephant in a multi-use landscape. PLoS One 2022; 17:e0271052. [PMID: 35802712 PMCID: PMC9269951 DOI: 10.1371/journal.pone.0271052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 06/23/2022] [Indexed: 11/18/2022] Open
Abstract
Elephants show a strong selection towards areas with high foraging opportunities at the landscape level making top-down decisions by first selecting patch types within landscapes and finally species within them. Understanding forage selection in a multi-use landscape is critical for prioritising patches for habitat management, ensuring availability of selected forage, helping in minimizing pressure on food crops and subsequent negative interactions with people. We assessed dry season forage selection in a multi-use landscape of West Bengal state, India. Relative forage use and relative plant species availability ratio were calculated to assess forage selection in a multi-use landscape comprising of the forest, tea estates, agricultural land, and human settlement. Forage use was assessed using the opportunistic feeding trail observation method (150.01 km). Stratified random sampling was used to assess plant species availability using the quadrat method (123 plots of 0.1 ha each). Among 286 plant species recorded, 132 plant species were consumed by elephants. A majority (80.21%) of plant species were consumed more than the proportional availability thereby showing selective foraging during the dry season in the study area. From forest to semi-open forest and open forest, canopy layer tree density and the total number of species decreased whereas invasive species density increased. This indicates the high impact on the forage species availability for elephants and the requirement of appropriate habitat management strategies. The presence of 32.14% of the selected forage species in human-use landscape alone demands the development of conservation interventions. This is the first study to assess forage selection by elephants in a multi-use landscape and used to prioritise conservation and management strategies at a landscape level.
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Affiliation(s)
- Priyanka Das
- Sálim Ali Centre for Ornithology and Natural History, Coimbatore, Tamil Nadu, India
- * E-mail: (PD); (HNK)
| | - Aritra Kshettry
- INSPIRE-Fellow, Department of Science and Technology, Government of India, New Delhi, India
| | - H. N. Kumara
- Sálim Ali Centre for Ornithology and Natural History, Coimbatore, Tamil Nadu, India
- * E-mail: (PD); (HNK)
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Troup G, Heinsohn R, King LE, Edwards KL. Exploring seasonal variation in the faecal glucocorticoid concentrations of African elephants (Loxodonta africana) living in a drought-prone, anthropogenic landscape. WILDLIFE RESEARCH 2022. [DOI: 10.1071/wr21003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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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]
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Pokharel SS, Yoneda H, Yanagi M, Sukumar R, Kinoshita K. The tail-tale of stress: an exploratory analysis of cortisol levels in the tail-hair of captive Asian elephants. PeerJ 2021; 9:e10445. [PMID: 33505782 PMCID: PMC7789861 DOI: 10.7717/peerj.10445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/07/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Assessment of physiological states by measuring biomarkers, such as cortisol, has significantly contributed to the monitoring of health, welfare and management of animals. Immunoreactive cortisol in hair (hC) has been used widely for deciphering 'stressful' past-events in various wild and captive animals. However, no such studies have been done in long-lived mammals. METHODS In this first exploratory study in elephants, we assessed (i) tail-hair growth rate (TGR) and (ii) hC levels in tail-hair samples from six captive Asian elephants from two zoos in Japan for comparing hC levels with zoo-keepers' records of distinct biological events over a c.0.5-2.0-year period. Tail-hair samples were cut into segments (based on monthly growth rate), pulverized or minced and a validated cortisol enzyme-immunoassay employed to measure hC levels. RESULTS When the hC levels of all individuals were compared with the keepers' records, a posteriori, most of the high hC levels were found to be associated with 'stressful' or distinct behavioural events such as pathological (anaemia, colic infection, skin infection, oral sores), psychosocial (reluctance in entering the enclosure, presence of a calf) and husbandry practice-related (contact trials/ space sharing) conditions, indicating that tail-hair indeed can be a potential 'retrospective' calendar of physiological health of an animal. CONCLUSIONS Our observations open up the possibility of using the tail-hair as an alternative matrix to reconstruct the physiological history of elephants.
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Affiliation(s)
- Sanjeeta Sharma Pokharel
- Wildlife Research Center, Kyoto University, Kyoto, Japan
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | | | - Moe Yanagi
- Wildlife Research Center, Kyoto University, Kyoto, Japan
| | - Raman Sukumar
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
- Institute for Advanced Study, Kyoto University, Kyoto, Japan
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LaDue CA, Vandercone RPG, Kiso WK, Freeman EW. Scars of human–elephant conflict: patterns inferred from field observations of Asian elephants in Sri Lanka. WILDLIFE RESEARCH 2021. [DOI: 10.1071/wr20175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
ContextHuman–elephant conflict (HEC) is a major threat to Asian elephants as humans and elephants are forced to share common resources. In Sri Lanka, human-dominated landscapes adjacent to protected areas promote high rates of HEC, especially in the form of crop-foraging by elephants. Crop-foraging can be dangerous to both elephants and humans involved in the conflict. Gunfire is a common way for human communities to deter crop-foraging elephants, and gunshot wounds are commonly described in this elephant population on necropsy.
AimsWe sought to quantify and describe unique scar patterns among Asian elephants in a protected area, Wasgamuwa National Park, attributed to HEC.
MethodsWe identified 38 adult female and 64 adult male elephants and recorded the age class and body condition of each with established standards. Using photographs, we counted the number, position, and relative size of all scars on each animal.
Key resultsMale elephants had significantly more scars than did females, and for males, the number of scars increased progressively with age. Additionally, male elephants with higher body conditions had more scars. Finally, males tended to have more scars towards the head, especially at older ages.
ConclusionsDifferences in total scar counts between the sexes in this population imply that male elephants in this area more frequently engage in HEC than do females, following observations previously described in the literature. Furthermore, the fact that male elephants acquired progressively more scars as they aged, and that fatter elephants had more scars, indicates that previous exposure to HEC may not have been a deterrent for future events among these males, and potentially, crops served as valuable food sources for these animals. Finally, the changing body locations of these scars with age in males possibly shows plastic behavioural responses during crop-foraging or lower tolerance by farmers towards habitual crop foragers.
ImplicationsThese results emphasise the need for animal-based approaches to HEC mitigation. Similarly, conservation managers in Sri Lanka and other elephant range countries should investigate similar methods that estimate patterns of HEC to develop effective management strategies directly targeting animals most likely to engage in conflict.
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Fürtbauer I, Christensen C, Bracken A, O'Riain MJ, Heistermann M, King AJ. Energetics at the urban edge: Environmental and individual predictors of urinary C-peptide levels in wild chacma baboons (Papio ursinus). Horm Behav 2020; 126:104846. [PMID: 32860833 DOI: 10.1016/j.yhbeh.2020.104846] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/23/2020] [Accepted: 08/21/2020] [Indexed: 10/23/2022]
Abstract
As human-modified landscapes encroach into natural habitats, wildlife face a reduction in natural food sources but also gain access to calorie-rich, human-derived foods. However, research into the energetics of wildlife living within and adjacent to urban and rural landscapes is lacking. C-peptide - a proxy for insulin production and a diagnostic tool for assessing pancreatic function in humans and domestic animals - can be quantified non-invasively from urine (uCP) and may provide a way to investigate the energetic correlates of living in human-altered landscapes. UCP is increasingly used in studies of primate energetics, and here we examine predictors of variation in uCP levels in n = 17 wild chacma baboons (Papio ursinus) living at the urban edge on the Cape Peninsula, South Africa. We find that uCP was positively associated with food provisioning and negatively with night fasting. UCP levels were comparable between winter and summer but significantly lower during spring, possibly driven by consumption of energy-rich seeds during summer and more human-derived foods during winter. UCP was elevated in pregnant females and similar for lactating and cycling females. We find no effect of dominance rank on uCP. Samples collected with synthetic Salivettes had significantly lower uCP levels than directly pipetted samples. Overall, our results indicate that uCP is a reliable, non-invasive measure of energy balance and intake in baboons, and suggest potential energetic benefits of living at the urban edge. More broadly, studies of uCP may offer unique insight into the environmental control of hormone-behaviour relationships in species crossing natural and urban environments.
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Affiliation(s)
- Ines Fürtbauer
- Department of Biosciences, College of Science, Swansea University, SA2 8PP Swansea, UK; Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa.
| | - Charlotte Christensen
- Department of Biosciences, College of Science, Swansea University, SA2 8PP Swansea, UK; Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa
| | - Anna Bracken
- Department of Biosciences, College of Science, Swansea University, SA2 8PP Swansea, UK; Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa
| | - M Justin O'Riain
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa
| | | | - Andrew J King
- Department of Biosciences, College of Science, Swansea University, SA2 8PP Swansea, UK; Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa
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Troup G, Doran B, Au J, King LE, Douglas-Hamilton I, Heinsohn R. Movement tortuosity and speed reveal the trade-offs of crop raiding for African elephants. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Oduor S, Brown J, Macharia GM, Boisseau N, Murray S, Obade P. Differing physiological and behavioral responses to anthropogenic factors between resident and non-resident African elephants at Mpala Ranch, Laikipia County, Kenya. PeerJ 2020; 8:e10010. [PMID: 33062433 PMCID: PMC7528812 DOI: 10.7717/peerj.10010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/31/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Heterogeneous landscapes like those of Laikipia County, Kenya consist of a mosaic of land-use types, which may exert differential physiological effects on elephants that occupy and traverse them. Understanding behavioral and physiological states of wild African elephants in response to the challenges of living in human-dominated landscapes is therefore important for conservation managers to evaluate risks imposed by elephants to humans and vice versa. Several conservation physiology tools have been developed to assess how animals respond to both natural and anthropogenic changes, and determine biological impacts. This study investigated how migratory and avoidance behavioral to vehicle presence, and vegetation quality affected fecal glucocorticoid (GC) metabolite (FGM) concentrations in African elephants at Mpala Ranch, Laikipia County, Kenya. METHODS The study compared adrenal glucocorticoid activity of resident elephants that live within Mpala (n = 57) and non-resident elephants whose space use patterns overlap several ranches (n = 99) in Laikipia County, Kenya. Fecal samples were collected for a 4-month period between April and August for analysis of FGM concentrations. Behavioral reactions to research vehicles and body condition also were assessed. Satellite images from Terra Moderate Resolution Imaging (MODIS MOD13Q1) were downloaded and processed using Google Earth Engine to calculate a Normalized Difference Vegetation Index (NDVI) as a measure of vegetation quality. RESULTS As expected, there was a positive correlation between avoidance behavior to vehicle presence and FGM concentrations in both resident and non-resident elephants, whereas there was an inverse relationship between FGM concentrations and NDVI values. Our study also found a positive influence of age on the FGM concentrations, but there were no relationships between FGM and sex, social group type, herd size, and body condition. However, contrary to our expectations, resident elephants had higher FGM concentrations than non-residents. DISCUSSION Findings reveal elephants with stronger avoidance responses to research vehicles and resident elephants with relatively smaller home ranges exhibited higher FGM concentrations within the Mpala Ranch, Kenya and surrounding areas. Higher vegetative quality within the ranges occupied by non-resident elephants in Laikipia may be one reason for lower FGM, and an indication that the non-residents are tracking better forage quality to improve energy balance and reduce overall GC output. Additionally, our study found a positive influence of age, but no other demographic variables on FGM concentrations. Finally, adrenal glucocorticoid activity was inversely related to vegetative quality. Our findings can help conservation managers better understand how behavior and environment influences the physiological states of African elephants, and how management intervention might mitigate negative human-elephant interactions.
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Affiliation(s)
- Sandy Oduor
- Research, Mpala Research Centre, Nanyuki, Laikipia, Kenya
| | - Janine Brown
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
| | - Geoffrey M. Macharia
- Department of Environmental Science, Kenyatta University, Nairobi, Nairobi, Kenya
| | - Nicole Boisseau
- Endocrine Lab, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
| | - Suzan Murray
- Global Health Program, Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Paul Obade
- Department of Environmental Science, Kenyatta University, Nairobi, Nairobi, Kenya
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Naha D, Dash SK, Chettri A, Roy A, Sathyakumar S. Elephants in the neighborhood: patterns of crop-raiding by Asian elephants within a fragmented landscape of Eastern India. PeerJ 2020; 8:e9399. [PMID: 32676222 PMCID: PMC7335499 DOI: 10.7717/peerj.9399] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/30/2020] [Indexed: 11/20/2022] Open
Abstract
Loss of forest cover, rise in human populations and fragmentation of habitats leads to decline in biodiversity and extinction of large mammals globally. Elephants, being the largest of terrestrial mammals, symbolize global conservation programs and co-occur with humans within multiple-use landscapes of Asia and Africa. Within such shared landscapes, poaching, habitat loss and extent of human-elephant conflicts (HEC) affect survival and conservation of elephants. HEC are severe in South Asia with increasing attacks on humans, crop depredation and property damage. Such incidents reduce societal tolerance towards elephants and increase the risk of retaliation by local communities. We analyzed a 2-year dataset on crop depredation by Asian elephants (N = 380) events in North Bengal (eastern India). We also explored the effect of landscape, anthropogenic factors (area of forest, agriculture, distance to protected area, area of human settlements, riverine patches and human density) on the spatial occurrence of such incidents.Crop depredation showed a distinct nocturnal pattern (22.00-06:00) and majority of the incidents were recorded in the monsoon and post-monsoon seasons. Results of our spatial analysis suggest that crop depredation increased with an increase in the area of forest patches, agriculture, presence of riverine patches and human density. Probability of crop depredation further increased with decreasing distance from protected areas. Villages within 1.5 km of a forest patch were most affected. Crop raiding incidents suggest a deviation from the "high-risk high-gain male biased" foraging behavior and involved proportionately more mixed groups (57%) than lone bulls (43%). Demographic data suggest that mixed groups comprised an average of 23 individuals with adult and sub adult females, bulls and calves. Crop depredation and fatal elephant attacks on humans were spatially clustered with eastern, central and western parts of North Bengal identified as hotspots of HEC. Our results will help to prioritize mitigation measures such as prohibition of alcohol production within villages, improving condition of riverine patches, changing crop composition, fencing agriculture fields, implement early warning systems around protected areas and training local people on how to prevent conflicts.
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Affiliation(s)
- Dipanjan Naha
- Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Suraj Kumar Dash
- Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Abhisek Chettri
- Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Akashdeep Roy
- Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Sambandam Sathyakumar
- Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
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Szott ID, Pretorius Y, Ganswindt A, Koyama NF. Normalized difference vegetation index, temperature and age affect faecal thyroid hormone concentrations in free-ranging African elephants. CONSERVATION PHYSIOLOGY 2020; 8:coaa010. [PMID: 32577285 PMCID: PMC7297438 DOI: 10.1093/conphys/coaa010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/21/2020] [Accepted: 02/02/2020] [Indexed: 05/03/2023]
Abstract
Conservation biologists can use hormone measurements to assess animals' welfare, reproductive state, susceptibility to stressors, as well as energy expenditure. Quantifying hormone concentrations from faecal samples is particularly advantageous as samples can be collected without disturbing animals' behaviour. In order for an endocrine marker to be useful for wildlife managers, we need to understand how extrinsic and intrinsic factors affect hormone concentrations in free-ranging animal populations. Thyroid hormones are linked to basal metabolic rate and energy expenditure. Previous research demonstrated that triiodothyronine (T3) can be measured successfully in faecal matter of African elephants, Loxodonta africana. However, to our knowledge, research into factors affecting changes in elephant T3 levels has only been carried out in captive elephants so far. Thus, we present the first study of faecal T3 metabolite (mT3) concentrations of a large population of free-ranging African elephants. Over 15 months, we collected faecal samples from identified (n = 43 samples) and unidentified (n = 145 samples) individuals in Madikwe Game Reserve, South Africa. We investigated whether vegetative productivity [normalized difference vegetation index (NDVI)] in interaction with mean monthly temperature, age and sex affected mT3 concentrations. We found a significant negative interaction effect of NDVI and temperature. Increasing NDVI was related to higher concentrations of mT3, but increasing temperature was related to a decrease in mT3 concentrations in individually identified and unidentified elephants. In unidentified individuals, juvenile elephants had significantly higher mT3 concentrations compared to adult elephants. Faecal T3 can successfully be quantified in samples from free-ranging elephant populations and thus provides insight into energy expenditure in large herbivores.
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Affiliation(s)
- Isabelle D Szott
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Yolanda Pretorius
- Mammal Research Institute, University of Pretoria, Hatfield 0028, South Africa
- Southern African Wildlife College, Hoedspruit 1380, South Africa
| | - Andre Ganswindt
- Mammal Research Institute, University of Pretoria, Hatfield 0028, South Africa
- Endocrine Research Laboratory, Department of Anatomy and Physiology, University of Pretoria, Onderstepoort 0110, South Africa
| | - Nicola F Koyama
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK
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Srinivasaiah N, Kumar V, Vaidyanathan S, Sukumar R, Sinha A. All-Male Groups in Asian Elephants: A Novel, Adaptive Social Strategy in Increasingly Anthropogenic Landscapes of Southern India. Sci Rep 2019; 9:8678. [PMID: 31273235 PMCID: PMC6609637 DOI: 10.1038/s41598-019-45130-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/29/2019] [Indexed: 01/11/2023] Open
Abstract
Male Asian elephants are known to adopt a high-risk high-gain foraging strategy by venturing into agricultural areas and feeding on nutritious crops in order to improve their reproductive fitness. We hypothesised that the high risks to survival posed by increasingly urbanising and often unpredictable production landscapes may necessitate the emergence of behavioural strategies that allow male elephants to persist in such landscapes. Using 1445 photographic records of 248 uniquely identified male Asian elephants over a 23-month period, we show that male Asian elephants display striking emergent behaviour, particularly the formation of stable, long-term all-male groups, typically in non-forested or human-modified and highly fragmented areas. They remained solitary or associated in mixed-sex groups, however, within forested habitats. These novel, large all-male associations, may constitute a unique life history strategy for male elephants in the high-risk but resource-rich production landscapes of southern India. This may be especially true for the adolescent males, which seemed to effectively improve their body condition by increasingly exploiting anthropogenic resources when in all-male groups. This observation further supports our hypothesis that such emergent behaviours are likely to constitute an adaptive strategy for male Asian elephants that may be forced to increasingly confront anthropogenically intrusive environments.
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Affiliation(s)
- Nishant Srinivasaiah
- National Institute of Advanced Studies, Animal Behaviour and Cognition Programme, Bengaluru, 560012, India.
| | - Vinod Kumar
- Foundation for Ecological Research, Advocacy and Learning, Pondicherry, 605101, India
| | - Srinivas Vaidyanathan
- Foundation for Ecological Research, Advocacy and Learning, Pondicherry, 605101, India
| | - Raman Sukumar
- Indian Institute of Science, Centre for Ecological Sciences, Bengaluru, 560012, India
| | - Anindya Sinha
- National Institute of Advanced Studies, Animal Behaviour and Cognition Programme, Bengaluru, 560012, India.,Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
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Gautam H, Arulmalar E, Kulkarni MR, Vidya TNC. NDVI is not reliable as a surrogate of forage abundance for a large herbivore in tropical forest habitat. Biotropica 2019. [DOI: 10.1111/btp.12651] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hansraj Gautam
- Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
| | - Evangeline Arulmalar
- Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
| | - Mihir R. Kulkarni
- Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
| | - T. N. C. Vidya
- Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
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Pokharel SS, Seshagiri PB, Sukumar R. Influence of the number of calves and lactating adult females in a herd on the adrenocortical activity of free-ranging Asian elephants. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18163] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
ContextPhysiological stress has the potential to influence animal population persistence. The endangered Asian elephant (Elephas maximus) is involved in intense conflict with humans in many parts of its range, which likely leads to stress for individuals and groups, with consequences for population survival. Thus, it is important to understand how the elephants’ stress levels are influenced by socio-ecological factors when not directly exposed to human-induced threats, and to use this understanding to improve conservation and management strategies.
AimsThe present study was designed to provide baseline information on the link between socio-ecological factors and stress levels of undisturbed populations of elephants. The main aim was to determine the influence of a number of factors – herd size, season, number of calves and adult females present in a herd and their lactational status and body condition – on the adrenocortical activity of free-ranging adult female Asian elephants living in protected forests (without any direct exposure to human-induced threats), by measuring their faecal glucocorticoid metabolite (fGCM) levels.
MethodsA total of 145 fresh faecal samples were collected from 123 identified adult female elephants inhabiting Bandipur and Nagarahole National Parks of southern India, between the years 2013 and 2015. fGCM levels were measured by employing a group-specific standardised 11-oxoetiocholanolone enzyme immunoassay (EIA). A generalised linear mixed-effects model (GLMM) was used to assess the influence of socio-ecological factors on fGCM levels of adult female elephants.
Key resultsWhen fGCM levels were analysed with a GLMM, the following patterns were observed: fGCM levels were negatively correlated with the number of adult females (herd size) and positively correlated with the number of calves in a herd and active lactational status of an adult female. fGCM levels of adult female elephants were higher during the dry season (February to May) than wet season (August to December) and negatively correlated with body condition scores.
ConclusionsAdrenocortical activity of female elephants is significantly influenced by the number of calves and adult females present in the herd, seasonality and lactational status.
ImplicationsIt is important to consider the influence of multiple ecological and social correlates when assessing and interpreting the adrenocortical activity of Asian elephants. Our findings highlight the importance of maintaining the social structure of elephants in the wild to avoid detrimental effects on their physiological health. Insights from such assessments could be used to evaluate the stress in elephants that are involved in direct conflicts with humans to take appropriate management decisions for mitigating conflicts.
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