2,565 results on '"Douglas‐Hamilton, I."'
Search Results
2. African elephants address one another with individually specific name-like calls.
- Author
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Pardo MA, Fristrup K, Lolchuragi DS, Poole JH, Granli P, Moss C, Douglas-Hamilton I, and Wittemyer G
- Subjects
- Animals, Male, Female, Social Behavior, Elephants physiology, Vocalization, Animal
- Abstract
Personal names are a universal feature of human language, yet few analogues exist in other species. While dolphins and parrots address conspecifics by imitating the calls of the addressee, human names are not imitations of the sounds typically made by the named individual. Labelling objects or individuals without relying on imitation of the sounds made by the referent radically expands the expressive power of language. Thus, if non-imitative name analogues were found in other species, this could have important implications for our understanding of language evolution. Here we present evidence that wild African elephants address one another with individually specific calls, probably without relying on imitation of the receiver. We used machine learning to demonstrate that the receiver of a call could be predicted from the call's acoustic structure, regardless of how similar the call was to the receiver's vocalizations. Moreover, elephants differentially responded to playbacks of calls originally addressed to them relative to calls addressed to a different individual. Our findings offer evidence for individual addressing of conspecifics in elephants. They further suggest that, unlike other non-human animals, elephants probably do not rely on imitation of the receiver's calls to address one another., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)
- Published
- 2024
- Full Text
- View/download PDF
3. Female African elephant rumbles differ between populations and sympatric social groups.
- Author
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Pardo MA, Lolchuragi DS, Poole J, Granli P, Moss C, Douglas-Hamilton I, and Wittemyer G
- Abstract
Vocalizations often vary in structure within a species, from the individual to population level. Vocal differences among social groups and populations can provide insight into biological processes such as vocal learning and evolutionary divergence, with important conservation implications. As vocal learners of conservation concern, intraspecific vocal variation is of particular interest in elephants. We recorded calls from individuals in multiple, wild elephant social groups in two distinct Kenyan populations. We used machine learning to investigate vocal differentiation among individual callers, core groups, bond groups (collections of core groups) and populations. We found clear evidence for vocal distinctiveness at the individual and population level, and evidence for much subtler vocal differences among social groups. Social group membership was a better predictor of call similarity than genetic relatedness, suggesting that subtle vocal differences among social groups may be learned. Vocal divergence among populations and social groups has conservation implications for the effects of social disruption and translocation of elephants., Competing Interests: We declare we have no competing interests., (© 2024 The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
4. Behavioral responses of terrestrial mammals to COVID-19 lockdowns
- Author
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Tucker, M., Schipper, A., Adams, T., Attias, N., Avgar, T., Babic, N., Barker, K., Bastille-Rousseau, G., Behr, D., Belant, J., Beyer Jr, D., Blaum, N., Blount, D., Bockmühl, D., Pires Boulhosa, R. L., Brown, M., Buuveibaatar, B., Cagnacci, F., (0000-0003-0575-6408) Calabrese, J., Černe, R., Chamaillé-Jammes, S., Chan, A. N., Chase, M., Chaval, Y., Chenaux-Ibrahim, Y., Cherry, S., Ćirović, D., Çoban, E., Cole, E., Conlee, L., Courtemanch, A., Cozzi, G., Davidson, S., Debloois, D., Dejid, N., Denicola, V., Desbiez, A., Douglas-Hamilton, I., Drake, D., Egan, M., Eikelboom, J., Fagan, W., Farmer, M., Fennessy, J., Finnegan, S., Fleming, C., Fournier, B., Fowler, N., Gantchoff, M., Garnier, A., Gehr, B., Geremia, C., Goheen, J., Hauptfleisch, M., Hebblewhite, M., Heim, M., Hertel, A., Heurich, M., Hewison, M., Hodson, J., Hoffman, N., Hopcraft, G., Huber, D., Isaac, E., Janik, K., Ježek, M., Johansson, Ö., Jordan, N. R., Kaczensky, P., Kamaru, D., Kauffman, M., Kautz, T., Kays, R., Kelly, A., Kindberg, J., Krofel, M., Kusak, J., Lamb, C., Lasharr, T., Leimgruber, P., Leitner, H., Lierz, M., Linnell, J., Lkhagvaja, P., Long, R., López-Bao, J., Loretto, M.-C., Marchand, P., Martin, H., Martinez, L., Mcbride Jr, R., Mclaren, A., Meisingset, E., Melzheimer, J., Merrill, E., Middleton, A., Monteith, K., Moore, S., Moorter, B. V., Morellet, N., Morrison, T., Müller, R., Mysterud, A., Noonan, M., O’Connor, D., Olson, D., Olson, K., Ortega, A., Ossi, F., Panzacchi, M., Patchett, R., Patterson, B., Paula, R. C. D., Payne, J., Peters, W., Petroelje, T., Pitcher, B., Pokorny, B., Poole, K., Potočnik, H., Poulin, M.-P., Pringle, R., Prins, H., Ranc, N., Reljić, S., Robb, B., Röder, R., Rolandsen, C., Rutz, C., Salemgareyev, A., Samelius, G., Sayine-Crawford, H., Schooler, S., Şekercioğlu, Ç., Selva, N., Semenzato, P., Sergiel, A., Sharma, K., Shawler, A., Signer, J., Silovský, V., Silva, J., Simon, R., Smiley, R., Smith, D., Solberg, E., Soto, D., Spiegel, O., Stabach, J., Stacy-Dawes, J., Stahler, D., Stephenson, J., Stewart, C., Strand, O., Sunde, P., Svoboda, N., Swart, J., Thompson, J., Toal, K., Uiseb, K., Vanacker, M., Velilla, M., Verzuh, T., Wachter, B., Wagler, B., Whittington, J., Wikelski, M., Wilmers, C., Wittemyer, G., Young, J., Zięba, F., Zwijacz-Kozica, T., Huijbregts, M., Mueller, T., Tucker, M., Schipper, A., Adams, T., Attias, N., Avgar, T., Babic, N., Barker, K., Bastille-Rousseau, G., Behr, D., Belant, J., Beyer Jr, D., Blaum, N., Blount, D., Bockmühl, D., Pires Boulhosa, R. L., Brown, M., Buuveibaatar, B., Cagnacci, F., (0000-0003-0575-6408) Calabrese, J., Černe, R., Chamaillé-Jammes, S., Chan, A. N., Chase, M., Chaval, Y., Chenaux-Ibrahim, Y., Cherry, S., Ćirović, D., Çoban, E., Cole, E., Conlee, L., Courtemanch, A., Cozzi, G., Davidson, S., Debloois, D., Dejid, N., Denicola, V., Desbiez, A., Douglas-Hamilton, I., Drake, D., Egan, M., Eikelboom, J., Fagan, W., Farmer, M., Fennessy, J., Finnegan, S., Fleming, C., Fournier, B., Fowler, N., Gantchoff, M., Garnier, A., Gehr, B., Geremia, C., Goheen, J., Hauptfleisch, M., Hebblewhite, M., Heim, M., Hertel, A., Heurich, M., Hewison, M., Hodson, J., Hoffman, N., Hopcraft, G., Huber, D., Isaac, E., Janik, K., Ježek, M., Johansson, Ö., Jordan, N. R., Kaczensky, P., Kamaru, D., Kauffman, M., Kautz, T., Kays, R., Kelly, A., Kindberg, J., Krofel, M., Kusak, J., Lamb, C., Lasharr, T., Leimgruber, P., Leitner, H., Lierz, M., Linnell, J., Lkhagvaja, P., Long, R., López-Bao, J., Loretto, M.-C., Marchand, P., Martin, H., Martinez, L., Mcbride Jr, R., Mclaren, A., Meisingset, E., Melzheimer, J., Merrill, E., Middleton, A., Monteith, K., Moore, S., Moorter, B. V., Morellet, N., Morrison, T., Müller, R., Mysterud, A., Noonan, M., O’Connor, D., Olson, D., Olson, K., Ortega, A., Ossi, F., Panzacchi, M., Patchett, R., Patterson, B., Paula, R. C. D., Payne, J., Peters, W., Petroelje, T., Pitcher, B., Pokorny, B., Poole, K., Potočnik, H., Poulin, M.-P., Pringle, R., Prins, H., Ranc, N., Reljić, S., Robb, B., Röder, R., Rolandsen, C., Rutz, C., Salemgareyev, A., Samelius, G., Sayine-Crawford, H., Schooler, S., Şekercioğlu, Ç., Selva, N., Semenzato, P., Sergiel, A., Sharma, K., Shawler, A., Signer, J., Silovský, V., Silva, J., Simon, R., Smiley, R., Smith, D., Solberg, E., Soto, D., Spiegel, O., Stabach, J., Stacy-Dawes, J., Stahler, D., Stephenson, J., Stewart, C., Strand, O., Sunde, P., Svoboda, N., Swart, J., Thompson, J., Toal, K., Uiseb, K., Vanacker, M., Velilla, M., Verzuh, T., Wachter, B., Wagler, B., Whittington, J., Wikelski, M., Wilmers, C., Wittemyer, G., Young, J., Zięba, F., Zwijacz-Kozica, T., Huijbregts, M., and Mueller, T.
- Abstract
COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals’ 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.
- Published
- 2023
5. Accelerometers and simple algorithms identify activity budgets and body orientation in African elephants Loxodonta africana
- Author
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Soltis, J, King, L, Vollrath, F, and Douglas-Hamilton, I
- Subjects
Zoology ,QL1-991 ,Botany ,QK1-989 - Abstract
Accelerometers can be used to monitor animal behavior remotely, but validation is required for each species. Previously, we showed that accelerometer data in collars could be used to identify specific behaviors in African elephants Loxodonta africana, using complex analytical methods. Here, we show that simple methods can also be used to identify elephant activity levels and body orientation. Subjects were 6 African elephants: 3 at Disneyís Animal KingdomÆ, Florida, USA, and 3 in Samburu-Laikipia, Kenya. Each elephant wore a collar containing a tri-axial accelerometer positioned on top of the neck. Simultaneous video recordings allowed validation of accelerometer data against observed behavior. The standard deviation of the total acceleration was shown to be a valid measure of dynamic acceleration, differentiating activity levels associated with resting, feeding, bathing, walking, and rapid walking. The mean of the total acceleration was shown to be a valid measure of static acceleration, and indicated upright and recumbent orientations. Simulations showed how accuracy was affected by sample rate, number of axes examined, and analysis window lengths. Based on 34 continuous 24 h acceleration streams, the 6 elephants exhibited an average of 2.5 h of overnight recumbence associated with minimal movement, indicating sleep. Daily activity budgets exhibited periods of minimal activity (e.g. resting, 17%), low activity (e.g. feeding, 68%), medium activity (e.g. walking, 13%), and high activity (e.g. rapid walking, 2%). Kenyan elephants were slightly more active and exhibited less restful recumbence compared to zoo elephants. Accelerometers in elephant collars can detect activity levels that are associated with specific behaviors, and can detect body orientation as a proxy for sleep.
- Published
- 2016
- Full Text
- View/download PDF
6. Beehive fences as effective deterrents for crop-raiding elephants: field trials in northern Kenya
- Author
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King, LE, Douglas-Hamilton, I, and Vollrath, F
- Abstract
Increasing elephant populations in Kenya since 1989 have been widely praised as a conservation success story. However, where elephants and agricultural land overlap, incidents of human–elephant conflict are on the increase. Wildlife managers and farmers are now trying different farm-based deterrents to keep elephants out of crops. Here, we present data on the effectiveness of a novel beehive fence deployed in a Turkana community of 62 communally run farms in Kenya. Specifically, 1700m of beehive fences semi-surrounded the outer boundaries of seventeen farms, and we compared elephant farm invasion events with these and to seventeen neighbouring farms whose boundaries were ‘protected’ only by thorn bush barriers. We present data from 45 farm invasions, or attempted invasions, recorded over 2 years. Thirteen groups of elephants approached the beehive fences and turned away. Of the 32 successful farm invasions, only one bull elephant broke through the beehive fences. These results demonstrate that beehive fences are more effective than thorn bush barriers at deterring elephants and may have a role to play in alleviating farmer–elephant conflict. Additionally, the harvesting of 106kg of honey during the trial period suggests that beehive fences may also improve crop production and enhance rural livelihoods through honey sales.
- Published
- 2022
7. Land use drives differential resource selection by African elephants in the Greater Mara Ecosystem, Kenya.
- Author
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Wall J, Hahn N, Carroll S, Mwiu S, Goss M, Sairowua W, Tiedeman K, Kiambi S, Omondi P, Douglas-Hamilton I, and Wittemyer G
- Abstract
Understanding drivers of space use by African elephants is critical to their conservation and management, particularly given their large home-ranges, extensive resource requirements, ecological role as ecosystem engineers, involvement in human-elephant conflict and as a target species for ivory poaching. In this study we investigated resource selection by elephants inhabiting the Greater Mara Ecosystem in Southwestern Kenya in relation to three distinct but spatially contiguous management zones: (i) the government protected Maasai Mara National Reserve (ii) community-owned wildlife conservancies, and (iii) elephant range outside any formal wildlife protected area. We combined GPS tracking data from 49 elephants with spatial covariate information to compare elephant selection across these management zones using a hierarchical Bayesian framework, providing insight regarding how human activities structure elephant spatial behavior. We also contrasted differences in selection by zone across several data strata: sex, season and time-of-day. Our results showed that the strongest selection by elephants was for closed-canopy forest and the strongest avoidance was for open-cover, but that selection behavior varied significantly by management zone and selection for cover was accentuated in human-dominated areas. When contrasting selection parameters according to strata, variability in selection parameter values reduced along a protection gradient whereby elephants tended to behave more similarly (limited plasticity) in the human dominated, unprotected zone and more variably (greater plasticity) in the protected reserve. However, avoidance of slope was consistent across all zones. Differences in selection behavior was greatest between sexes, followed by time-of-day, then management zone and finally season (where seasonal selection showed the least differentiation of the contrasts assessed). By contrasting selection coefficients across strata, our analysis quantifies behavioural switching related to human presence and impact displayed by a cognitively advanced megaherbivore. Our study broadens the knowledge base about the movement ecology of African elephants and builds our capacity for both management and conservation., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
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8. Feasibility study on the spatial and temporal movement of Samburu's cattle and wildlife in Kenya using GPS radio-tracking, remote sensing and GIS
- Author
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Raizman, E.A., Rasmussen, H. Barner, King, L.E., Ihwagi, F.W., and Douglas-Hamilton, I.
- Published
- 2013
- Full Text
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9. Social dominance, seasonal movements, and spatial segregation in African elephants: a contribution to conservation behavior
- Author
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Wittemyer, G., Getz, W. M., Vollrath, F., and Douglas-Hamilton, I.
- Published
- 2007
10. Elephants and algorithms: a review of the current and future role of AI in elephant monitoring.
- Author
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Brickson L, Zhang L, Vollrath F, Douglas-Hamilton I, and Titus AJ
- Subjects
- Animals, Artificial Intelligence, Conservation of Natural Resources methods, Animals, Wild, Elephants
- Abstract
Artificial intelligence (AI) and machine learning (ML) present revolutionary opportunities to enhance our understanding of animal behaviour and conservation strategies. Using elephants, a crucial species in Africa and Asia's protected areas, as our focal point, we delve into the role of AI and ML in their conservation. Given the increasing amounts of data gathered from a variety of sensors like cameras, microphones, geophones, drones and satellites, the challenge lies in managing and interpreting this vast data. New AI and ML techniques offer solutions to streamline this process, helping us extract vital information that might otherwise be overlooked. This paper focuses on the different AI-driven monitoring methods and their potential for improving elephant conservation. Collaborative efforts between AI experts and ecological researchers are essential in leveraging these innovative technologies for enhanced wildlife conservation, setting a precedent for numerous other species.
- Published
- 2023
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11. Stability in a Multi-Species Assemblage of Large Herbivores in East Africa
- Author
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Prins, H. H. T. and Douglas-Hamilton, I.
- Published
- 1990
12. The Numbers and Distribution Patterns of Large Mammals in the Ruaha- Rungwa Area of Southern Tanzania
- Author
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Barnes, R. F. W. and Douglas-Hamilton, I.
- Published
- 1982
- Full Text
- View/download PDF
13. Behavioral responses of terrestrial mammals to COVID-19 lockdowns.
- Author
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Tucker MA, Schipper AM, Adams TSF, Attias N, Avgar T, Babic NL, Barker KJ, Bastille-Rousseau G, Behr DM, Belant JL, Beyer DE Jr, Blaum N, Blount JD, Bockmühl D, Pires Boulhosa RL, Brown MB, Buuveibaatar B, Cagnacci F, Calabrese JM, Černe R, Chamaillé-Jammes S, Chan AN, Chase MJ, Chaval Y, Chenaux-Ibrahim Y, Cherry SG, Ćirović D, Çoban E, Cole EK, Conlee L, Courtemanch A, Cozzi G, Davidson SC, DeBloois D, Dejid N, DeNicola V, Desbiez ALJ, Douglas-Hamilton I, Drake D, Egan M, Eikelboom JAJ, Fagan WF, Farmer MJ, Fennessy J, Finnegan SP, Fleming CH, Fournier B, Fowler NL, Gantchoff MG, Garnier A, Gehr B, Geremia C, Goheen JR, Hauptfleisch ML, Hebblewhite M, Heim M, Hertel AG, Heurich M, Hewison AJM, Hodson J, Hoffman N, Hopcraft JGC, Huber D, Isaac EJ, Janik K, Ježek M, Johansson Ö, Jordan NR, Kaczensky P, Kamaru DN, Kauffman MJ, Kautz TM, Kays R, Kelly AP, Kindberg J, Krofel M, Kusak J, Lamb CT, LaSharr TN, Leimgruber P, Leitner H, Lierz M, Linnell JDC, Lkhagvaja P, Long RA, López-Bao JV, Loretto MC, Marchand P, Martin H, Martinez LA, McBride RT Jr, McLaren AAD, Meisingset E, Melzheimer J, Merrill EH, Middleton AD, Monteith KL, Moore SA, Van Moorter B, Morellet N, Morrison T, Müller R, Mysterud A, Noonan MJ, O'Connor D, Olson D, Olson KA, Ortega AC, Ossi F, Panzacchi M, Patchett R, Patterson BR, de Paula RC, Payne J, Peters W, Petroelje TR, Pitcher BJ, Pokorny B, Poole K, Potočnik H, Poulin MP, Pringle RM, Prins HHT, Ranc N, Reljić S, Robb B, Röder R, Rolandsen CM, Rutz C, Salemgareyev AR, Samelius G, Sayine-Crawford H, Schooler S, Şekercioğlu ÇH, Selva N, Semenzato P, Sergiel A, Sharma K, Shawler AL, Signer J, Silovský V, Silva JP, Simon R, Smiley RA, Smith DW, Solberg EJ, Ellis-Soto D, Spiegel O, Stabach J, Stacy-Dawes J, Stahler DR, Stephenson J, Stewart C, Strand O, Sunde P, Svoboda NJ, Swart J, Thompson JJ, Toal KL, Uiseb K, VanAcker MC, Velilla M, Verzuh TL, Wachter B, Wagler BL, Whittington J, Wikelski M, Wilmers CC, Wittemyer G, Young JK, Zięba F, Zwijacz-Kozica T, Huijbregts MAJ, and Mueller T
- Subjects
- Animals, Humans, Movement, Animals, Wild physiology, Animals, Wild psychology, COVID-19 epidemiology, Mammals physiology, Mammals psychology, Quarantine, Animal Migration
- Abstract
COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.
- Published
- 2023
- Full Text
- View/download PDF
14. Movements and corridors of African elephants in relation to protected areas
- Author
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Douglas-Hamilton, I., Krink, T., and Vollrath, F.
- Published
- 2005
- Full Text
- View/download PDF
15. The socioecology of elephants: analysis of the processes creating multitiered social structures
- Author
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Wittemyer, G., Douglas-Hamilton, I., and Getz, W.M.
- Subjects
Elephants -- Analysis ,Proboscidea -- Analysis ,Zoology and wildlife conservation - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2004.08.018 Byline: G. Wittemyer, I. Douglas-Hamilton, W.M. Getz Abstract: In this paper, we investigate the formation and function of the multilevelled, fission-fusion social structure in a free-ranging African elephant, Loxodonta africana, population. We quantitatively identified the existence of four social tiers by using cluster analysis on individual association data. We assessed the effects of season and study period on social structuring and levels of cohesion within and among social units. We found that second-tier units, potentially the equivalent of the 'family', were stable across seasonal periods but the number of units increased as the study progressed and the population grew. It appears that these units were sufficiently small not to be influenced by ecologically related factors, such as resource competition, that might otherwise lead to them splitting. On the other hand, third- and fourth-tier units were significantly affected by season in a way that suggests a trade-off between ecological costs (e.g. from resource competition) and different social and ecological benefits (e.g. from predator defence, territoriality, knowledge sharing and rearing of young). Age structure also appeared to influence this multitiered social organization. The size of second-tier social units was significantly affected by the age of matriarchs: units lead by matriarchs likely to be grandmothers (i.e. females 35 years and older) were significantly larger than those lead by younger matriarchs. We present a conceptual framework for understanding the emergence of multiple-tier social structure from interactions driven by socioecological processes. This study is the first to use rigorous quantitative methods to statistically show the existence of four hierarchical tiers of social organization in a nonhuman animal. Additionally, our results elucidate the role that ecological processes play in producing complex social structures. Author Affiliation: (*) Department of Environmental Science, Policy and Management, University of California, Berkeley, U.S.A. (a ) Save the Elephants, Kenya (a ) Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa Article History: Received 17 June 2004; Revised 23 July 2004; Accepted 18 August 2004 Article Note: (miscellaneous) MS. number: A9821
- Published
- 2005
16. Age- and tactic-related paternity success in male African elephants
- Author
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Rasmussen, H.B., Okello, J.B.A., Wittemyer, G., Siegismund, H.R., Arctander, P., Vollrath, F., and Douglas-Hamilton, I.
- Published
- 2008
17. Noninvasive Genotyping and Mendelian Analysis of Microsatellites in African Savannah Elephants
- Author
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Okello, J. B. A., Wittemyer, G., Rasmussen, H. B., Douglas-Hamilton, I., Nyakaana, S., Arctander, P., and Siegismund, H. R.
- Published
- 2005
18. Challenges of using behavior to monitor anthropogenic impacts on wildlife: a case study on illegal killing of African elephants.
- Author
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Goldenberg, S. Z., Douglas‐Hamilton, I., Daballen, D., and Wittemyer, G.
- Subjects
ANTHROPOLOGY ,ELEPHANTS ,ANIMAL welfare ,HUMAN behavior ,ANIMALS ,WOUNDS & injuries - Abstract
Monitoring anthropogenic impacts on wildlife can be challenging, particularly when human activities affecting wildlife are cryptic. Using anti-predator behaviors as proxies for perceived pressure is appealing because of the relative ease with which they can be recorded and the presumed relationship between the threat of interest and a predator stimulus. However, behaviors are plastic and affected by factors unrelated to human activity. Consequently, it is critical to assess the relationship between behavioral indicators and their context before interpretation. In this study we used a combination of behavior, movement and demography from a threatened population of African elephants in northern Kenya to determine whether reaction to research vehicles was indicative of poaching pressure. We used mixed-effects models predicting reaction of elephants to observer vehicle approaches in which we treated individuals as random effects and included ecological, anthropogenic, spatial, social and demographic predictor variables. Contrary to our hypothesis, recorded levels of reactive behavior did not increase with poaching levels in either a population-level dataset or a data subset of individuals whose spatial behavior was precisely known via radio-tracking. Rather, primary productivity positively predicted reactive behavior in both datasets. This relationship was heightened by the presence of musth males in the radio-collar dataset. Reactivity was not related to the time since entering the protected areas, but increased among groups that spent less time in the protected areas. Inter-individual differences were apparent, suggesting the importance of inherent differences (e.g. personality) across groups. In our study, elephants plagued by a severe human threat did not react defensively to humans in another context, suggesting nuanced discrimination of threats. Our study demonstrates the caution that should be taken in designing studies that use behavioral indices to represent threat and contributes to a growing body of literature employing behavioral indicators to monitor wildlife populations of conservation concern. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. Moving in the Anthropocene: Global reductions in terrestrial mammalian movements
- Author
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Tucker, M A, Bohning-Gaese, K, Fagan, W F, Fryxell, J M, Van Moorter, B, Alberts, S C, Ali, A H, Allen, A M, Attias, N, Avgar, T, Bartlam-Brooks, H L A, Bayarbaatar, B, Belant, J L, Bertassoni, A, Beyer, D, Bidner, L, Van Beest, F M, Blake, S, Blaum, N, Bracis, C, Brown, D, De Bruyn, P J N, Cagnacci, F, Calabrese, J M, Camilo-Alves, C, Chamaille-Jammes, S, Chiaradia, A, Davidson, S C, Dennis, T, DeStefano, S, Diefenbach, D, Douglas-Hamilton, I, Fennessy, J, Fichtel, C F, Fiedler, W, Fischer, C, Fischhoff, I, Fleming, C H, Ford, A T, Fritz, S A, Gehr, B, Goheen, J R, Gurarie, E, Hebblewhite, M, Heurich, M, Hewison, A J M, Hof, C, Hurme, E, Isbell, L A, Janssen, R, Jeltsch, F, Kaczensky, P, Kane, A, Kappeler, P M, and Kauffman, M
- Published
- 2018
20. Moving in the Anthropocene: Global reductions in terrestrial mammalian movements
- Author
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Tucker, MA, Böhning-Gaese, K, Fagan, WF, Fryxell, JM, Van Moorter, B, Alberts, SC, Ali, AH, Allen, AM, Attias, N, Avgar, T, Bartlam-Brooks, H, Bayarbaatar, B, Belant, JL, Bertassoni, A, Beyer, D, Bidner, L, Van Beest, FM, Blake, S, Blaum, N, Bracis, C, Brown, D, De Bruyn, PJN, Cagnacci, F, Calabrese, JM, Camilo-Alves, C, Chamaillé-Jammes, S, Chiaradia, A, Davidson, SC, Dennis, T, DeStefano, S, Diefenbach, D, Douglas-Hamilton, I, Fennessy, J, Fichtel, C, Fiedler, W, Fischer, C, Fischhoff, I, Fleming, CH, Ford, AT, Fritz, SA, Gehr, B, Goheen, JR, Gurarie, E, Hebblewhite, M, Heurich, M, Hewison, AJM, Hof, C, Hurme, E, Isbell, LA, Janssen, R, Jeltsch, F, Kaczensky, P, Kane, A, Kappeler, PM, Kauffman, M, Kays, R, Kimuyu, D, Koch, F, Kranstauber, B, LaPoint, S, Leimgruber, P, Linnell, JDC, López-López, P, Markham, AC, Mattisson, J, Medici, EP, Mellone, U, Merrill, E, De MirandaMourão, G, Morato, RG, Morellet, N, Morrison, TA, Díaz-Muñoz, SL, Mysterud, A, Nandintsetseg, D, Nathan, R, Niamir, A, Odden, J, O'Hara, RB, Oliveira-Santos, LGR, Olson, KA, Patterson, BD, De Paula, RC, Pedrotti, L, Reineking, B, Rimmler, M, Rogers, TL ; https://orcid.org/0000-0002-7141-4177, Rolandsen, CM, Rosenberry, CS, Rubenstein, DI, Safi, K, Saïd, S, Sapir, N, Sawyer, H, Schmidt, NM, Selva, N, Sergiel, A, Shiilegdamba, E, Silva, JP, Singh, N, Wilson, John, Tucker, MA, Böhning-Gaese, K, Fagan, WF, Fryxell, JM, Van Moorter, B, Alberts, SC, Ali, AH, Allen, AM, Attias, N, Avgar, T, Bartlam-Brooks, H, Bayarbaatar, B, Belant, JL, Bertassoni, A, Beyer, D, Bidner, L, Van Beest, FM, Blake, S, Blaum, N, Bracis, C, Brown, D, De Bruyn, PJN, Cagnacci, F, Calabrese, JM, Camilo-Alves, C, Chamaillé-Jammes, S, Chiaradia, A, Davidson, SC, Dennis, T, DeStefano, S, Diefenbach, D, Douglas-Hamilton, I, Fennessy, J, Fichtel, C, Fiedler, W, Fischer, C, Fischhoff, I, Fleming, CH, Ford, AT, Fritz, SA, Gehr, B, Goheen, JR, Gurarie, E, Hebblewhite, M, Heurich, M, Hewison, AJM, Hof, C, Hurme, E, Isbell, LA, Janssen, R, Jeltsch, F, Kaczensky, P, Kane, A, Kappeler, PM, Kauffman, M, Kays, R, Kimuyu, D, Koch, F, Kranstauber, B, LaPoint, S, Leimgruber, P, Linnell, JDC, López-López, P, Markham, AC, Mattisson, J, Medici, EP, Mellone, U, Merrill, E, De MirandaMourão, G, Morato, RG, Morellet, N, Morrison, TA, Díaz-Muñoz, SL, Mysterud, A, Nandintsetseg, D, Nathan, R, Niamir, A, Odden, J, O'Hara, RB, Oliveira-Santos, LGR, Olson, KA, Patterson, BD, De Paula, RC, Pedrotti, L, Reineking, B, Rimmler, M, Rogers, TL ; https://orcid.org/0000-0002-7141-4177, Rolandsen, CM, Rosenberry, CS, Rubenstein, DI, Safi, K, Saïd, S, Sapir, N, Sawyer, H, Schmidt, NM, Selva, N, Sergiel, A, Shiilegdamba, E, Silva, JP, Singh, N, and Wilson, John
- Abstract
Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint.We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission.
- Published
- 2018
21. Beehive fences as a multidimensional conflict-mitigation tool for farmers coexisting with elephants
- Author
-
King, L, Lala, F, Nzumu, H, Mwambingu, E, and Douglas-Hamilton, I
- Subjects
Conservation of Natural Resources ,Farmers ,Elephants ,Animals ,Humans ,Environment Design ,Kenya ,Ecosystem - Abstract
Increasing habitat fragmentation and human population growth in Africa has resulted in an escalation in human-elephant conflict between small-scale farmers and free-ranging African elephants (Loxodonta Africana). In 2012 Kenya Wildlife Service (KWS) implemented the national 10-year Conservation and Management Strategy for the Elephant in Kenya, which includes an action aimed at testing whether beehive fences can be used to mitigate human-elephant conflict. From 2012 to 2015, we field-tested the efficacy of beehive fences to protect 10 0.4-ha farms next to Tsavo East National Park from elephants. We hung a series of beehives every 10 m around the boundary of each farm plot. The hives were linked with strong wire. After an initial pilot test with 2 farms, the remaining 8 of 10 beehive fences also contained 2-dimensional dummy hives between real beehives to help reduce the cost of the fence. Each trial plot had a neighboring control plot of the same size within the same farm. Of the 131 beehives deployed 88% were occupied at least once during the 3.5-year trial. Two hundred and fifty-three elephants, predominantly 20-45 years old entered the community farming area, typically during the crop- ripening season. Eighty percent of the elephants that approached the trial farms were kept out of the areas protected by the beehive fences, and elephants that broke a fence were in smaller than average groups. Beehive fences not only kept large groups of elephants from invading the farmland plots but the farmers also benefited socially and financially from the sale of 228 kg of elephant-friendly honey. As news of the success of the trial spread, a further 12 farmers requested to join the project, bringing the number of beehive fence protected farms to 22 and beehives to 297. This demonstrates positive adoption of beehive fences as a community mitigation tool. Understanding the response of elephants to the beehive fences, the seasonality of crop raiding and fence breaking, and the willingness of the community to engage with the mitigation method will help contribute to future management strategies for this high human-elephant conflict hotspot and other similar areas in Kenya.
- Published
- 2017
22. Poaching of African elephants indirectly decreases population growth through lowered orphan survival.
- Author
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Parker JM, Webb CT, Daballen D, Goldenberg SZ, Lepirei J, Letitiya D, Lolchuragi D, Leadismo C, Douglas-Hamilton I, and Wittemyer G
- Subjects
- Animals, Conservation of Natural Resources, Crime, Population Dynamics, Population Growth, Elephants
- 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., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)- Published
- 2021
- Full Text
- View/download PDF
23. Feasibility study on the spatial and temporal movement of Samburu's cattle and wildlife in Kenya using GPS radio-tracking, remote sensing and GIS
- Author
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Raizman, E. A., Rasmussen, Henrik Barner, King, L. E., Ihwagi, F. W., Douglas-Hamilton, I., Raizman, E. A., Rasmussen, Henrik Barner, King, L. E., Ihwagi, F. W., and Douglas-Hamilton, I.
- Published
- 2013
24. Human footprint and protected areas shape elephant range across Africa.
- Author
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Wall J, Wittemyer G, Klinkenberg B, LeMay V, Blake S, Strindberg S, Henley M, Vollrath F, Maisels F, Ferwerda J, and Douglas-Hamilton I
- Subjects
- Africa, Animals, Conservation of Natural Resources, Ecosystem, Forests, Humans, Water, Elephants
- Abstract
Over the last two millennia, and at an accelerating pace, the African elephant (Loxodonta spp. Lin.) has been threatened by human activities across its range.
1-7 We investigate the correlates of elephant home range sizes across diverse biomes. Annual and 16-day elliptical time density home ranges8 were calculated by using GPS tracking data collected from 229 African savannah and forest elephants (L. africana and L. cyclotis, respectively) between 1998 and 2013 at 19 sites representing bushveld, savannah, Sahel, and forest biomes. Our analysis considered the relationship between home range area and sex, species, vegetation productivity, tree cover, surface temperature, rainfall, water, slope, aggregate human influence, and protected area use. Irrespective of these environmental conditions, long-term annual ranges were overwhelmingly affected by human influence and protected area use. Only over shorter, 16-day periods did environmental factors, particularly water availability and vegetation productivity, become important in explaining space use. Our work highlights the degree to which the human footprint and existing protected areas now constrain the distribution of the world's largest terrestrial mammal.9 , 10 A habitat suitability model, created by evaluating every square kilometer of Africa, predicts that 18,169,219 km2 would be suitable as elephant habitat-62% of the continent. The current elephant distribution covers just 17% of this potential range of which 57.4% falls outside protected areas. To stem the continued extirpation and to secure the elephants' future, effective and expanded protected areas and improved capacity for coexistence across unprotected range are essential., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2021
- Full Text
- View/download PDF
25. Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants
- Author
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Okello, J B A, Wittemyer, G, Rasmussen, Henrik Barner, Arctander, P, Nyakaana, S, Douglas-Hamilton, I, Siegismund, H R, Okello, J B A, Wittemyer, G, Rasmussen, Henrik Barner, Arctander, P, Nyakaana, S, Douglas-Hamilton, I, and Siegismund, H R
- Abstract
Udgivelsesdato: 2008-Sep, Two hundred years of elephant hunting for ivory, peaking in 1970-1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions of such human-mediated events on this keystone species. Using Bayesian coalescent-based genetic methods to evaluate time-specific changes in effective population size, we analysed genetic variation in 20 highly polymorphic microsatellite loci from 400 elephants inhabiting the greater Samburu-Laikipia region of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid-Holocene period of climatic drying in tropical Africa. Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates the importance of climatic history in shaping the distribution and genetic history of a keystone species and highlights the utility of coalescent-based demographic approaches in unravelling ancestral demographic events despite a lack of ancient samples. Unique insights into the genetic signature of mid-Holocene climatic change in Africa and effects of recent poaching pressure on elephants are discussed.
- Published
- 2008
26. Noninvasive Genotyping and Mendelian Analysis of Microsatellites in African Savannah Elephants
- Author
-
Okello, John Bosco A., Wittemyer, G., Rasmussen, H. B., Douglas-Hamilton, I., Nyakaana, Silvester, Arctander, Peter, Siegismund, Hans Redlef, Okello, John Bosco A., Wittemyer, G., Rasmussen, H. B., Douglas-Hamilton, I., Nyakaana, Silvester, Arctander, Peter, and Siegismund, Hans Redlef
- Abstract
Udgivelsesdato: November, We obtained fresh dung samples from 202 (133 mother-offspring pairs) savannah elephants (Loxodonta africana) in Samburu, Kenya, and genotyped them at 20 microsatellite loci to assess genotyping success and errors. A total of 98.6% consensus genotypes was successfully obtained, with allelic dropout and false allele rates at 1.6% (n = 46) and 0.9% (n = 37) of heterozygous and total consensus genotypes, respectively, and an overall genotyping error rate of 2.5% based on repeat typing. Mendelian analysis revealed consistent inheritance in all but 38 allelic pairs from mother-offspring, giving an average mismatch error rate of 2.06%, a possible result of null alleles, mutations, genotyping errors, or inaccuracy in maternity assignment. We detected no evidence for large allele dropout, stuttering, or scoring error in the dataset and significant Hardy-Weinberg deviations at only two loci due to heterozygosity deficiency. Across loci, null allele frequencies were low (range: 0.000-0.042) and below the 0.20 threshold that would significantly bias individual-based studies. The high genotyping success and low errors observed in this study demonstrate reliability of the method employed and underscore the application of simple pedigrees in noninvasive studies. Since none of the sires were included in this study, the error rates presented are just estimates.
- Published
- 2005
27. Seasonal variation in the ranging behavior of elephants in the Laikipia‐Samburu ecosystem.
- Author
-
Kuria, Loise W., Kimuyu, Duncan M., Kinyanjui, Mwangi J., Wittemyer, George, and Ihwagi, Festus W.
- Subjects
AFRICAN elephant ,PROBABILITY density function ,ELEPHANT behavior ,HOME range (Animal geography) ,WATER supply ,RAINFALL - Abstract
African savanna elephants are a highly mobile species that ranges widely across the diversity of ecosystems they inhabit. In xeric environments, elephant movement patterns are largely dictated by the availability of water and suitable forage resources, which can drive strong seasonal changes in their movement behavior. In this study, we analyzed a unique movement dataset from 43 collared elephants, collected over a period of 10 years, to assess the degree to which seasonal changes influences home range size of elephants in the semi‐arid, Laikipia‐Samburu ecosystem of northern Kenya. Auto‐correlated Kernel Density Estimation (AKDE) was used to estimate elephants' seasonal home range size. For each individual elephant, we also calculated seasonal home range shifts, as the distance between wet season home range centroids and dry season home range centroids. Core areas (50% AKDE isopleths) of all individual elephants ranged from 3 to 1743 km2 whereas total home range sizes (the 95% AKDE isopleths) ranged between 15 and 10,677 km2. Core areas and home range sizes were 67% and 61% larger, respectively, during the wet season than during the dry season. On average, the core area centroids for all elephants were 17 km away from the nearest river (range 0.2–150.3 km). Females had their core areas closer to the river than males (13.5 vs. 27.5 km). Females differed from males in their response to seasonal variation. Specifically, females tended to occupy areas farther from the river during the wet season, while males occupied areas further from the river during the dry season. Our study highlights how elephants adjust their space use seasonally, which can be incorporated into conservation area planning in the face of increased uncertainty in rainfall patterns due to climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Challenges of using behavior to monitor anthropogenic impacts on wildlife: a case study on illegal killing of African elephants
- Author
-
Goldenberg, S. Z., primary, Douglas-Hamilton, I., additional, Daballen, D., additional, and Wittemyer, G., additional
- Published
- 2016
- Full Text
- View/download PDF
29. Intensity of elephant occupancy in Marsabit protected area, Kenya : effects of biophysical and anthropogenic factors
- Author
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Ngene, S.M., Skidmore, A.K., van Gils, H.A.M.J., van Wieren, S.E., Prins, H.H.T., Douglas-Hamilton, I., Toxopeus, A.G., Aranovich, M., Dufresne, O., Department of Natural Resources, UT-I-ITC-FORAGES, and Faculty of Geo-Information Science and Earth Observation
- Subjects
METIS-294592 - Published
- 2012
30. Walk or stride? a question for roaming herds of elephants in Marsabit, protected area
- Author
-
Ngene, S.M., Skidmore, A.K., van Gils, H.A.M.J., Prins, H.H.T., Toxopeus, A.G., Douglas-Hamilton, I., Aranovich, M., Dufresne, O., Department of Natural Resources, UT-I-ITC-FORAGES, and Faculty of Geo-Information Science and Earth Observation
- Subjects
METIS-294593 - Published
- 2012
31. Movement reveals reproductive tactics in male elephants.
- Author
-
Taylor LA, Vollrath F, Lambert B, Lunn D, Douglas-Hamilton I, and Wittemyer G
- Subjects
- Aggression, Animals, Male, Movement, Reproduction, Sexual Behavior, Animal, Elephants
- Abstract
Long-term bio-logging has the potential to reveal how movements, and hence life-history trade-offs, vary over a lifetime. Reproductive tactics in particular may vary as individuals' trade-off current investment versus lifetime fitness. Male African savanna elephants (Loxodona africana) provide a telling example of balancing body growth with reproductive fitness due to the combination of indeterminate growth and strongly delineated periods of sexual activity (musth), which results in reproductive tactics that alter with age. Our study aims to quantify the extent to which male elephants alter their movement patterns, and hence energetic allocation, in relation to (a) reproductive state and (b) age, and (c) to determine whether musth periods can be detected directly from GPS tracking data. We used a combination of GPS tracking data and visual observations of 25 male elephants ranging in age from 20 to 52 years to examine the influence of reproductive state and age on movement. We then used a three-state hidden Markov model (HMM) to detect musth behaviour in a subset of sequential tracking data. Our results demonstrate that male elephants increased their daily mean speed and range size with age and in musth. Furthermore, non-musth speed decreased with age, presumably reflecting a shift towards energy acquisition during non-musth. Thus, despite similar speeds and marginally larger ranges between reproductive states at age 20, by age 50, males were travelling 2.0 times faster in a 3.5 times larger area in musth relative to non-musth. The distinctiveness of musth periods over age 35 meant the three-state HMM could automatically detect musth movement with high sensitivity and specificity, but could not for the younger age class. We show that male elephants increased their energetic allocation into reproduction with age as the probability of reproductive success increases. Given that older male elephants tend to be both the target of legal trophy hunting and illegal poaching, man-made interference could drive fundamental changes in elephant reproductive tactics. Bio-logging, as our study reveals, has the potential both to quantify mature elephant reproductive tactics remotely and to be used to institute proactive management strategies around the reproductive behaviour of this charismatic keystone species., (© 2019 The Authors Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)
- Published
- 2020
- Full Text
- View/download PDF
32. Of tusks and trunks: A review of craniofacial evolutionary anatomy in elephants and extinct Proboscidea.
- Author
-
Nabavizadeh A
- Abstract
While being the largest living terrestrial mammals, elephants are best known for their highly modified and uniquely elaborate craniofacial anatomy-most notably with respect to their often-massive tusks and intricately muscular, multifunctional proboscis (i.e., trunk). For over a century, studies of extinct proboscidean relatives of today's elephants have presented hypotheses regarding the evolutionary history of the crania and tusks of these animals and their bearing on the evolution of the proboscis. Herein, I explore major functional characteristics of the proboscidean head. I give a brief review of the anatomy of tusks and dentition, the feeding apparatus, and proboscis in extant elephants and explore their overall bearing in elephant feeding behavior as well as other aspects of their ecology. I also review the evolution of the proboscidean head, with a synthetic analysis of studies and further speculation exploring the interconnected evolutionary roles of tusk morphology and use, feeding anatomy and functional implications thereof, and proboscis anatomy and use in the ancestry of elephants. Notable emphasis is given to the evolutionary role of initial elongation of the mandibular symphysis in the development of the proboscis in many proboscideans. Subsequent secondary shortening of the symphysis and elevation of the temporal region and occiput allowed for a pendulous trunk and proal feeding in living elephants and other proboscidean groups with highly lophodont dentition., (© 2024 American Association for Anatomy.)
- Published
- 2024
- Full Text
- View/download PDF
33. Inter-generational change in African elephant range use is associated with poaching risk, primary productivity and adult mortality.
- Author
-
Goldenberg SZ, Douglas-Hamilton I, and Wittemyer G
- Subjects
- Animals, Female, Homing Behavior, Kenya, Longevity, Animal Distribution, Conservation of Natural Resources, Elephants, Grassland
- 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., (© 2018 The Author(s).)
- Published
- 2018
- Full Text
- View/download PDF
34. Applying network theory to animal movements to identify properties of landscape space use.
- Author
-
Bastille-Rousseau G, Douglas-Hamilton I, Blake S, Northrup JM, and Wittemyer G
- Subjects
- Animal Distribution, Animals, Deer, Elephants, Movement, Turtles, Ecology methods, Spatial Behavior
- Abstract
Network (graph) theory is a popular analytical framework to characterize the structure and dynamics among discrete objects and is particularly effective at identifying critical hubs and patterns of connectivity. The identification of such attributes is a fundamental objective of animal movement research, yet network theory has rarely been applied directly to animal relocation data. We develop an approach that allows the analysis of movement data using network theory by defining occupied pixels as nodes and connection among these pixels as edges. We first quantify node-level (local) metrics and graph-level (system) metrics on simulated movement trajectories to assess the ability of these metrics to pull out known properties in movement paths. We then apply our framework to empirical data from African elephants (Loxodonta africana), giant Galapagos tortoises (Chelonoidis spp.), and mule deer (Odocoileous hemionus). Our results indicate that certain node-level metrics, namely degree, weight, and betweenness, perform well in capturing local patterns of space use, such as the definition of core areas and paths used for inter-patch movement. These metrics were generally applicable across data sets, indicating their robustness to assumptions structuring analysis or strategies of movement. Other metrics capture local patterns effectively, but were sensitive to specified graph properties, indicating case specific applications. Our analysis indicates that graph-level metrics are unlikely to outperform other approaches for the categorization of general movement strategies (central place foraging, migration, nomadism). By identifying critical nodes, our approach provides a robust quantitative framework to identify local properties of space use that can be used to evaluate the effect of the loss of specific nodes on range wide connectivity. Our network approach is intuitive, and can be implemented across imperfectly sampled or large-scale data sets efficiently, providing a framework for conservationists to analyze movement data. Functions created for the analyses are available within the R package moveNT., (© 2018 by the Ecological Society of America.)
- Published
- 2018
- Full Text
- View/download PDF
35. The movement of African elephants in a human-dominated land-use mosaic.
- Author
-
Graham, M. D., Douglas-Hamilton, I., Adams, W. M., and Lee, P. C.
- Subjects
AFRICAN elephant ,WILDLIFE conservation ,LOXODONTA ,LAND use ,HABITATS - Abstract
Land outside of gazetted protected areas is increasingly seen as important to the future of elephant persistence in Africa. However, other than inferential studies on crop raiding, very little is understood about how elephants Loxodonta africana use and are affected by human-occupied landscapes. This is largely a result of restrictions in technology, which made detailed assessments of elephant movement outside of protected areas challenging. Recent advances in radio telemetry have changed this, enabling researchers to establish over a 24-h period where tagged animals spend their time. We assessed the movement of 13 elephants outside of gazetted protected areas across a range of land-use types on the Laikipia plateau in north-central Kenya. The elephants monitored spent more time at night than during the day in areas under land use that presented a risk of mortality associated with human occupants. The opposite pattern was found on large-scale ranches where elephants were tolerated. Furthermore, speed of movement was found to be higher where elephants were at risk. These results demonstrate that elephants facultatively alter their behaviour to avoid risk in human-dominated landscapes. This helps them to maintain connectivity between habitat refugia in fragmented land-use mosaics, possibly alleviating some of the potential negative impacts of fragmentation. At the same time, however, it allows elephants to penetrate smallholder farmland to raid crops. The greater the amount of smallholder land within an elephant's range, the more it was utilized, with consequent implications for conflict. These findings underscore the importance of (1) land-use planning to maintain refugia; (2) incentives to prevent further habitat fragmentation; (3) the testing and application of conflict mitigation measures where fragmentation has already taken place. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
36. Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants.
- Author
-
OKELLO, J. B. A., WITTEMYER, G., RASMUSSEN, H. B., ARCTANDER, P., NYAKAANA, S., DOUGLAS-HAMILTON, I., and SIEGISMUND, H. R.
- Subjects
ELEPHANTS ,ELEPHANT hunting ,IVORY ,GENES ,MICROSATELLITE repeats - Abstract
Two hundred years of elephant hunting for ivory, peaking in 1970–1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions of such human-mediated events on this keystone species. Using Bayesian coalescent-based genetic methods to evaluate time-specific changes in effective population size, we analysed genetic variation in 20 highly polymorphic microsatellite loci from 400 elephants inhabiting the greater Samburu-Laikipia region of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid–Holocene period of climatic drying in tropical Africa. Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates the importance of climatic history in shaping the distribution and genetic history of a keystone species and highlights the utility of coalescent-based demographic approaches in unravelling ancestral demographic events despite a lack of ancient samples. Unique insights into the genetic signature of mid-Holocene climatic change in Africa and effects of recent poaching pressure on elephants are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
37. Conserving large populations of lions – the argument for fences has holes
- Author
-
Creel, S., primary, Becker, M. S., additional, Durant, S. M., additional, M'Soka, J., additional, Matandiko, W., additional, Dickman, A. J., additional, Christianson, D., additional, Dröge, E., additional, Mweetwa, T., additional, Pettorelli, N., additional, Rosenblatt, E., additional, Schuette, P., additional, Woodroffe, R., additional, Bashir, S., additional, Beudels‐Jamar, R. C., additional, Blake, S., additional, Borner, M., additional, Breitenmoser, C., additional, Broekhuis, F., additional, Cozzi, G., additional, Davenport, T. R. B., additional, Deutsch, J., additional, Dollar, L., additional, Dolrenry, S., additional, Douglas‐Hamilton, I., additional, Fitzherbert, E., additional, Foley, C., additional, Hazzah, L., additional, Henschel, P., additional, Hilborn, R., additional, Hopcraft, J. G. C., additional, Ikanda, D., additional, Jacobson, A., additional, Joubert, B., additional, Joubert, D., additional, Kelly, M. S., additional, Lichtenfeld, L., additional, Mace, G. M., additional, Milanzi, J., additional, Mitchell, N., additional, Msuha, M., additional, Muir, R., additional, Nyahongo, J., additional, Pimm, S., additional, Purchase, G., additional, Schenck, C., additional, Sillero‐Zubiri, C., additional, Sinclair, A. R. E., additional, Songorwa, A. N., additional, Stanley‐Price, M., additional, Tehou, C. A., additional, Trout, C., additional, Wall, J., additional, Wittemyer, G., additional, and Zimmermann, A., additional
- Published
- 2013
- Full Text
- View/download PDF
38. Demographic status of elephants in the Samburu and Buffalo Springs National Reserves, Kenya.
- Author
-
Wittemyer, G., Daballen, D., Rasmussen, H., Kahindi, O., and Douglas-Hamilton, I.
- Subjects
AFRICAN elephant ,POACHING ,HUNTING ,IVORY ,WILDLIFE conservation ,DEMOGRAPHY ,SAMBURU (African people) - Abstract
Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
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39. Accelerometers in collars identify behavioral states in captive African elephants Loxodonta africana
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Soltis, J, primary, Wilson, RP, additional, Douglas-Hamilton, I, additional, Vollrath, F, additional, King, LE, additional, and Savage, A, additional
- Published
- 2012
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40. History of Animals using Isotope Records (HAIR): A 6-year dietary history of one family of African elephants
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Cerling, T. E., primary, Wittemyer, G., additional, Ehleringer, J. R., additional, Remien, C. H., additional, and Douglas-Hamilton, I., additional
- Published
- 2009
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41. Population Genetic Structure of Savannah Elephants in Kenya: Conservation and Management Implications
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Okello, J. B. A., primary, Masembe, C., additional, Rasmussen, H. B., additional, Wittemyer, G., additional, Omondi, P., additional, Kahindi, O., additional, Muwanika, V. B., additional, Arctander, P., additional, Douglas-Hamilton, I., additional, Nyakaana, S., additional, and Siegismund, H. R., additional
- Published
- 2008
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42. Age- and tactic-related paternity success in male African elephants
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Rasmussen, H.B., primary, Okello, J.B.A., additional, Wittemyer, G., additional, Siegismund, H.R., additional, Arctander, P., additional, Vollrath, F., additional, and Douglas-Hamilton, I., additional
- Published
- 2007
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43. Geospatial analysis of elephant habitat suitability and movement for mapping the elephant corridor in Dalma Wildlife Sanctuary (India).
- Author
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Chaudhary SK, Pandey AC, and Parida BR
- Subjects
- Animals, India, Forests, Environmental Monitoring methods, Animals, Wild, Elephants, Ecosystem, Conservation of Natural Resources
- Abstract
Wildlife and natural resources constitute an integral part of the ecosystem, whereas human interventions dismantled the living conditions of the wildlife. This is testified in the Dalma Wildlife Sanctuary (DWS) where the habitats of Asian elephants have changed due to human intervention and deforestation over the decades. The present study aimed to assess the elephant habitat suitability in the DWS of Jharkhand state (India) using the geospatial parameters such as forest density, degree of slope, proximity to water bodies, land use land cover, proximity to agricultural land, built-up density, and road density. The analytical hierarchical process technique was utilized to determine habitat preference and selection of relevant factors to categorize criteria. The study revealed that about 6.7% (26.74 km
2 ) of the area is very highly suitable for elephant habitat, while 52.26% (208.49 km2 ) of the forest area was found highly suitable. The most suitable habitat was identified in the core parts of the forest, while the least suitable areas were found in the southern part, where the presence of roads, built-up, and agricultural land was prominent. It was also observed that most human-elephant conflicts were exhibited in the low and very low suitable areas, while 90% of the elephant movement was witnessed in the high and very high suitable areas. Among the four identified corridors, three are inactive, and their location corresponds with low to very low suitable habitats. The study identified the migratory corridor routes inside the sanctuary where effective management is required for the conservation of elephant habitats and minimizing conflicts., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)- Published
- 2024
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44. The effects of human-caused mortality on mammalian cooperative breeders: a synthesis.
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Ausband DE, Rebholz PF, and Petrillo L
- 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., (© 2024 Cambridge Philosophical Society.)
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- 2024
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45. Male elephant management in AZA institutions: Current status and priorities for the future.
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LaDue CA, Davis M, Emory R, and Snyder RJ
- Subjects
- Animals, Male, Conservation of Natural Resources methods, Animal Welfare, Elephants physiology, Animals, Zoo, Animal Husbandry methods
- Abstract
Asian elephant (Elephas maximus) and African savanna elephant (Loxodonta africana) populations collectively managed by ex-situ facilities accredited by the Association of Zoos and Aquariums (AZA) face sustainability challenges. Among the priorities to strengthen animal wellbeing and population sustainability is male elephant management. We conducted a survey of AZA facilities currently housing male elephants to assess the status, challenges, and priorities in three areas of male elephant management: musth, socialization, and semen collection. Surveys were administered to elephant care teams at AZA-accredited institutions between November 2022 and February 2023, and we received responses from 34 institutions (91.9% of AZA-accredited facilities holding adult male elephants), housing 32 adult male Asians and 26 adult male Africans. Most facilities prioritized breeding and male socialization over musth management and semen collection (although most facilities acknowledged that all these efforts are important), citing leadership support and staffing as most important to achieve male management goals. Behaviors most commonly accompanying musth included reduced appetite, difficulty training or shifting, human-directed aggression, and interest in females. Musth timing was variable between males and facilities. Most males were well-socialized with females and/or other males, though elephant compatibility and facility design were limiting factors in managing socialization. Although 60.6% of facilities collected semen or were training for semen collection, very few male elephants could reliably provide viable semen samples, challenging assisted reproductive efforts that could bolster population sustainability in both species. Together, our results provide a better understanding of the state of male elephant management, offering specific areas deserving of research and development to enhance wellbeing and sustainability., (© 2024 Wiley Periodicals LLC.)
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- 2024
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46. Moving in the Anthropocene: Global reductions in terrestrial mammalian movements.
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Tucker MA, Böhning-Gaese K, Fagan WF, Fryxell JM, Van Moorter B, Alberts SC, Ali AH, Allen AM, Attias N, Avgar T, Bartlam-Brooks H, Bayarbaatar B, Belant JL, Bertassoni A, Beyer D, Bidner L, van Beest FM, Blake S, Blaum N, Bracis C, Brown D, de Bruyn PJN, Cagnacci F, Calabrese JM, Camilo-Alves C, Chamaillé-Jammes S, Chiaradia A, Davidson SC, Dennis T, DeStefano S, Diefenbach D, Douglas-Hamilton I, Fennessy J, Fichtel C, Fiedler W, Fischer C, Fischhoff I, Fleming CH, Ford AT, Fritz SA, Gehr B, Goheen JR, Gurarie E, Hebblewhite M, Heurich M, Hewison AJM, Hof C, Hurme E, Isbell LA, Janssen R, Jeltsch F, Kaczensky P, Kane A, Kappeler PM, Kauffman M, Kays R, Kimuyu D, Koch F, Kranstauber B, LaPoint S, Leimgruber P, Linnell JDC, López-López P, Markham AC, Mattisson J, Medici EP, Mellone U, Merrill E, de Miranda Mourão G, Morato RG, Morellet N, Morrison TA, Díaz-Muñoz SL, Mysterud A, Nandintsetseg D, Nathan R, Niamir A, Odden J, O'Hara RB, Oliveira-Santos LGR, Olson KA, Patterson BD, Cunha de Paula R, Pedrotti L, Reineking B, Rimmler M, Rogers TL, Rolandsen CM, Rosenberry CS, Rubenstein DI, Safi K, Saïd S, Sapir N, Sawyer H, Schmidt NM, Selva N, Sergiel A, Shiilegdamba E, Silva JP, Singh N, Solberg EJ, Spiegel O, Strand O, Sundaresan S, Ullmann W, Voigt U, Wall J, Wattles D, Wikelski M, Wilmers CC, Wilson JW, Wittemyer G, Zięba F, Zwijacz-Kozica T, and Mueller T
- Subjects
- Animals, Geographic Information Systems, Humans, Animal Migration, Human Activities, Mammals
- Abstract
Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission., (Copyright © 2018, The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
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- 2018
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47. Status and trends of elephants in the Serengeti-Mara ecosystem.
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DUBLIN, H. T. and DOUGLAS-HAMILTON, I.
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- 1987
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48. GPS telemetry of forest elephants in Central Africa: results of a preliminary study
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Blake, S., primary, Douglas‐Hamilton, I., additional, and Karesh, W. B., additional
- Published
- 2001
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49. Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade.
- Author
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Cerling TE, Barnette JE, Chesson LA, Douglas-Hamilton I, Gobush KS, Uno KT, Wasser SK, and Xu X
- Subjects
- Animals, Cameroon, Commerce, Congo, Conservation of Natural Resources, Crime, Gabon, Population Dynamics trends, Carbon Radioisotopes metabolism, Elephants, Radiometric Dating methods
- Abstract
Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≥0.5 ton) made between 2002 and 2014 show that most ivory (ca 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little "old" ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of "rapid" transit than ivory originating in the Tridom region of Cameroon-Gabon-Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products., Competing Interests: I.D.-H. is chief executive officer of Save the Elephants, which provided partial funding for this research, and K.S.B. is employed by Vulcan, Inc., which provided partial funding for this research through the Paul G. Allen Family Foundation.
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- 2016
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50. A model illustrating the changes in forest elephant numbers caused by poaching
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MICHELMORE, F., primary, BEARDSLEY, K., additional, BARNES, R. F. W., additional, and DOUGLAS-HAMILTON, I., additional
- Published
- 1994
- Full Text
- View/download PDF
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