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2. Mapping out a future for ungulate migrations : Limited mapping of migrations hampers conservation

Author

Kauffman, M.J., Cagnacci, F., Chamaillé-Jammes, S., Hebblewhite, M., Hopcraft, J.G.C., Merkle, J.A., Mueller, T., Mysterud, A., Peters, W., Roettger, C., Steingisser, A., Meacham, J.E., Abera, K., Adamczewski, J., Aikens, E.O., Bartlam-Brooks, H., Bennitt, E., Berger, J., Boyd, C., Côté, S.D., Debeffe, L., Dekrout, A.S., Dejid, N., Donadio, E., Dziba, L., Fagan, W.F., Fischer, C., Focardi, S., Fryxell, J.M., Fynn, R.W.S., Geremia, C., González, B.A., Gunn, A., Gurarie, E., Heurich, M., Hilty, J., Hurley, M., Johnson, A., Joly, K., Kaczensky, P., Kendall, C.J., Kochkarev, P., Kolpaschikov, L., Kowalczyk, R., van Langevelde, F., Binbin V, L., Lobora, A.L., Loison, A., Madiri, T.H., Mallon, D., Marchand, P., Medellin, R.A., Meisingset, E., Merrill, E., Middleton, A.D., Monteith, K.L., Morjan, M., Morrison, T.A., Mumme, S., Naidoo, R., Novaro, A., Ogutu, J.O., Olson, K.A., Oteng-Yeboah, A., Ovejero, R.J.A., Owen-Smith, N., Paasivaara, A., Packer, C., Panchenko, D., Pedrotti, L., Plumptre, A.J., Rolandsen, C.M., Said, S., Salemgareyev, A., Savchenko, A., Savchenko, P., Sawyer, H., Selebatso, M., Skroch, M., Solberg, E., Stabach, J.A., Strand, O., Suitor, M.J., Tachiki, Y., Trainor, A., Tshipa, A., Virani, M.Z., Vynne, C., Ward, S., Wittemyer, G., Wenjing, X., and Zuther, S.

Subjects
Settore BIO/07 - ECOLOGIA
Published
2021

6. Large herbivore assemblages in a changing climate: incorporating water dependence and thermoregulation

Author

Veldhuis, M. P., Kihwele, E. S., Cromsigt, J. P. G. M., Ogutu, J. O., Hopcraft, J. G. C., Owen-Smith, N., Olff, H., Veldhuis, M. P., Kihwele, E. S., Cromsigt, J. P. G. M., Ogutu, J. O., Hopcraft, J. G. C., Owen-Smith, N., and Olff, H.

Abstract

The coexistence of different species of large herbivores (ungulates) in grasslands and savannas has fascinated ecologists for decades. However, changes in climate, land-use and trophic structure of ecosystems increasingly jeopardise the persistence of such diverse assemblages. Body size has been used successfully to explain ungulate niche differentiation with regard to food requirements and predation sensitivity. But this single trait axis insufficiently captures interspecific differences in water requirements and thermoregulatory capacity and thus sensitivity to climate change. Here, we develop a two-dimensional trait space of body size and minimum dung moisture content that characterises the combined food and water requirements of large herbivores. From this, we predict that increased spatial homogeneity in water availability in drylands reduces the number of ungulate species that will coexist. But we also predict that extreme droughts will cause the larger, water-dependent grazers as wildebeest, zebra and buffalo?dominant species in savanna ecosystems ? to be replaced by smaller, less water-dependent species. Subsequently, we explore how other constraints such as predation risk and thermoregulation are connected to this two-dimensional framework. Our novel framework integrates multiple simultaneous stressors for herbivores and yields an extensive set of testable hypotheses about the expected changes in large herbivore community composition following climate change.

Published
2019

8. EFFECTS OF ELEPHANTS ON ECOSYSTEMS AND BIODIVERSITY

Author

Kerley, G.I.H., Landman, M., Kruger, L., Owen-Smith, N., Balfour, D., de Boer, W.F., Gaylard, A., Lindsay, K., and Slotow, R.

Subjects
south africa, wildlife, Wildlife Ecology and Conservation, loxodonta africana, Life Science, wildlife management, wildbeheer, wild, zuid-afrika, PE&RC
Published
2018

11. Evidence of reduced individual heterogeneity in adult survival of long-lived species

Author

Péron, G, Gaillard, JM, Barbraud, C, Bonenfant, C, Charmantier, A, Choquet, R, Coulson, Timothy, Grosbois, V, Loison, A, Marzolin, G, Owen-Smith, N, Pardo, D, Plard, F, Pradel, R, Toïgo, C, Gimenez, O, Département écologie évolutive [LBBE], Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Smithsonian Conservation Biology Institute, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Biodémographie évolutive, Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Department of Zoology [Oxford], Wildlife Conservation Research Unit [Oxford], University of Oxford-University of Oxford, Animal et gestion intégrée des risques (UPR AGIRs), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Laboratoire d'Ecologie Alpine (LECA ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), School of Animal, University of the Witwatersrand [Johannesburg] (WITS), Evolution, adaptation et comportement, CNERA Cervidés Sanglier, Office National de la Chasse et de la Faune Sauvage, Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Paul-Valéry - Montpellier 3 (UM3), University of Oxford [Oxford]-University of Oxford [Oxford], Animal et gestion intégrée des risques (Cirad-Bios-UPR 22 AGIRs), Département Systèmes Biologiques (Cirad-BIOS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Laboratoire d'Ecologie Alpine (LECA), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
comparative analyses, Chamois, random-effect models, Capra ibex, Biologie animale, Chevreuil, L52 - Physiologie animale - Croissance et développement, life-history evolution, mixture models, individual differences, ComputingMilieux_MISCELLANEOUS, Capture-recapture, L10 - Génétique et amélioration des animaux, Longévité, Cycle de développement, [SDE]Environmental Sciences, Analyse comparative, L20 - Écologie animale, Pagodroma nivea, vertebrates, Analyse de séries chronologiques
Abstract

The canalization hypothesis postulates that the rate at which trait variation generates variation in the average individual fitness in a population determines how buffered traits are against environmental and genetic factors. The ranking of a species on the slow-fast continuum - the covariation among life-history traits describing species-specific life cycles along a gradient going from a long life, slow maturity, and low annual reproductive output, to a short life, fast maturity, and high annual reproductive output - strongly correlates with the relative fitness impact of a given amount of variation in adult survival. Under the canalization hypothesis, long-lived species are thus expected to display less individual heterogeneity in survival at the onset of adulthood, when reproductive values peak, than short-lived species. We tested this life-history prediction by analysing long-term time series of individual-based data in nine species of birds and mammals using capture-recapture models. We found that individual heterogeneity in survival was higher in species with short-generation time (< 3 years) than in species with long generation time (> 4 years). Our findings provide the first piece of empirical evidence for the canalization hypothesis at the individual level from the wild.

Published
2016

12. Aspects of the feeding ecology of a browsing ruminant: the kudu

Author

Owen-Smith, N., Cooper, S.M., and Novellie, P.A.

Subjects
Feeding ecology, diet, ruminant, browser, kudu
Abstract

Forbs form the preferred dietary component of the kudu (Tragelaphus sfrepsiceros). This preference was associated with the high nutrient content of their leaves and less fibrous stem material relative to trees and shrubs. Woody browse was most sought after during the early growing season when their new shoots are softest and forbs are least available. Kudus are able to maintain foraging efficiency for most of the year by substituting alternative food species as availability of preferred species declines. Woody species armed with structural defences are preferred during the growing season owing to higher nutrient content in their leaves than in unarmed species. During the dry season when food availability becomes limiting, the preference shifts in favour of species offering highest eating rates. Certain species were consistently rejected despite adequate nutrient levels presumably because of the presence of unidentified chemical deterrents in their leaves.Forbe is die voorkeur dieetkomponent van die koedoe (Tragelaphus sfrepslceros). Hierdie voorkeur spruit uit die ho€ voedingswaardev an hul blare en die feit dat hul minder veselrige stammateriaal het in vergelyking met bome en struike. Houtagtige takvoer was die gewildste tydens die vroe€ groeiseisoenw anneerd ie jong lote die sagste is en forbe die minste beskikbaar. Koedoes is in staat om die grootste gedeelte van die jaar effektief te wei deur van alternatiewe voedselspesiesg ebruik te maak soos die beskikbaarheidv an die voorkeur species afneem. Houtagtige spesies bewapen met strukturele beskerming word verkies tydens die groeiseisoen omdat hul blare meer voedingswaardeh et as di6 van die onbewapende spesies. Tydens die dro€ seisoen wanneer die beskikbaarheid van kos beperk raak, verskuif die voorkeur na spesies wat die vinnigste vreettempo toelaat. Sekere spesies is voortdurend verwerp ten spyte van voldoende voedingstof vlakke,w aarskynliko mdat daar ongeldentifiseerdech emiese afweermiddelsi n hul blare voorkom,Keywords: Feeding ecology, diet, ruminant, browser, kudu

Published
2016

15. Facultative predation and scavenging by mammalian carnivores: seasonal, regional and intra-guild comparisons

Author

Pereira, L., Owen-Smith, N., and Moleon, M.

Abstract

The extent to which vertebrate carnivores shift facultatively between predation and scavenging has recently been emphasized. Potentially, all carnivores have to do is wait until animals succumb to the debilitating effects of advancing age. However, this may be insufficient because of intense competition among other scavengers and decomposers for food. Moreover, the availability of carcasses of animals dying from causes other than predation varies seasonally, so carnivores must be adapted to exploit various sources of food through the seasonal cycle.\ud \ud We explore how mammalian carnivores cope with seasonality in carrion supply and in prey vulnerability to predation. We focus mainly on large carnivores and ungulates, and compare especially ecological communities in northern temperate and African savanna ecosystems.\ud \ud When carrion is scarce, carnivores can (i) take advantage of temporarily vulnerable segments of prey populations, such as newborn young, heavily pregnant females and males distracted or debilitated by reproduction, (ii) switch to carcass remains left by or stolen from other carnivores, or (iii) exploit small animals and non‐animal food sources.\ud \ud Relationships between carnivores tending towards predation or scavenging can be both competitive and facilitative. Top carnivores may provide a supply of carcasses throughout the year, which subsidizes scavengers when carrion availability from other sources is low. Alterations of seasonal patterns due to anthropogenic environmental change may enhance the role of top carnivores as buffers of anthropogenic perturbations of natural processes.\ud \ud Megaherbivores, which are not normally regarded as prey but can provide huge carrion subsidies, may strongly influence interspecific interactions between carnivores and the proportion of food flowing towards scavenging relative to predation.\ud \ud Relationships among carnivores based on hunting vs. scavenging strategies are flexible and subject to changes in response to circumstances. Their functional complexity is relevant for assessing the effects of global change on ecosystem function.

Published
2013

17. Empirical Evidence of Density Dependence in Populations of Large Herbivores

Author

Bonenfant, C., Gaillard, J.-M., Coulson, T., Festa-Bianchet, M., Loison, A., Garel, M., Egil Loe, L., Blanchard, P., Pettorelli, N., Owen-Smith, N., Du Toit, J., Duncan, P., Biodémographie évolutive, Département écologie évolutive [LBBE], Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), and Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.OT]Life Sciences [q-bio]/Other [q-bio.OT]
Published
2009

18. Condensed tannin in Eragrostis chloromelas leaves deters feeding by a generalist grasshopper

Author

Dini, J and Owen-Smith, N

Subjects
allelochemicals, botany, brown locust, Eragrostis chloromelas, feeding, grasshoppers, insect herbivory, insects, leaves, Locustana pardalina, tannin
Abstract

We investigated the feeding responses of a generalist grasshopper, the brown locust(Locusta pardalina), to leaves of the grass Eragrostis chloromelas differing in polyphenol content. For three specimens of E. chloromelas, the presence of condensed tannin in epidermal cells was confirmed by histochemical staining, while two specimens lacked polyphenols. Locusts selected the leaves of tannin-free plants for feeding significantly more frequently than leaves from plants containing tannins. Findings suggest that the food choice of some locusts was affected by the presence of tannins, although variability in feeding responses among individuals was apparent. However, we cannot exclude the possibility that other differences existed between the specimens.Keywords: allelochemicals; botany; brown locust; Eragrostis chloromelas; feeding; grasshoppers; insect herbivory; insects; leaves; Locustana pardalina; tanninAfrican Journal of Range and Forage Science 1995, 12(2): 49–52

Published
2007

21. Effects of elephants on ecosystems and biodiversity

Author

Kerley, G.I.H., Landman, M., Kruger, L., Owen-Smith, N., Balfour, D., de Boer, W.F., Gaylard, A., Lindsay, K., Slotow, R., Kerley, G.I.H., Landman, M., Kruger, L., Owen-Smith, N., Balfour, D., de Boer, W.F., Gaylard, A., Lindsay, K., and Slotow, R.

Published
2008

32. Coping with savanna seasonality: comparative daily activity patterns of African ungulates as revealed by GPS telemetry.

Author

Owen‐Smith, N. and Goodall, V.

Subjects
*QUAGGA, *SABLE antelope, *AFRICAN buffalo, *TIME management, *SEASONAL effects on wildlife
Abstract

Daily activity schedules and time budgets reveal how animals cope with changing environmental conditions in securing food and evading enemies. Theory suggests that animals in populations limited by food availability should be energy maximizers in their foraging time allocation, while those regulated by predation should minimize their mobile activity levels. We compared daily and seasonal variation in activity states among three species of grazing ungulates coexisting in the same region of Kruger National Park, South Africa, and for one of these species between regions differing in rainfall. These grazers differed in body size and digestive physiology, potentially affecting their activity patterns. Hourly movement rates recorded by GPS telemetry were partitioned among activity states by applying independent mixture models. All three species showed activity peaks during the early morning and late afternoon, while resting prevailed pre-dawn as well as through midday. African buffalo showed the strongest diel variation in activity and greatest depression of midday activity, consistent with their large body size. Buffalo maintained similar levels of activity through the day and night, while zebra and sable antelope showed higher levels of diurnal than nocturnal activity. During the late dry season, zebra and coexisting sable, but not buffalo, showed elevated foraging and total mobile activity. Zebra devoted more time to foraging than both ruminants, consistent with greater food intake requirements for hindgut digestion. Sable antelope inhabiting the region with higher rainfall showed similar activity levels to the sable herd in the drier area, but slower rates of movement while foraging and travelling and less elevation in foraging time towards the end of the dry season. Observed patterns indicated subtly changing interplay among different constraints bearing on activity patterns over the diel and seasonal cycles, especially those related to digestive physiology. Simplistic concepts of energy maximization or time minimization were not supported. [ABSTRACT FROM AUTHOR]

Published
2014
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36. Shrinking sable antelope numbers in Kruger National Park: what is suppressing population recovery?

Author

Owen-Smith, N., Chirima, G. J., Macandza, V., Le Roux, E., and Gordon, Iain

Subjects
*SABLE antelope, *HIPPOTRAGUS, *RAINFALL, *PREDATION, *ALLEE effect
Abstract

Sable antelope numbers in the Kruger National Park have declined substantially since the mid-1980s and have shown little recovery despite improved rainfall conditions. We used aerial survey records to investigate how changes in herd numbers, herd sizes, calf proportions and consequent changes in the distribution range of breeding herds contributed to this situation. Both herd sizes and herd numbers decreased in the drier northern half of the park, coupled with low calf proportions, especially during and following a severe drought, while declines in these measures became evident later in the wetter southern half. Herd extirpations led to a 25% contraction in the local distribution range of sable antelope, although some of these herds had only become established during the high rainfall period in the late 1970s. Local population trends were not related to increases in zebra numbers potentially attracting more predators. Compensatory density dependence in the population growth rate was no longer evident after 1986 during the period of the population decline. The population trajectory modelled from rainfall relationships indicated that the depressed population growth rate relative to rainfall apparent after 1986 has persisted, implicating either enduring habitat degradation or continuing high predation pressure. The pattern of the population decline and subsequent lack of recovery raises the possibility that an Allee effect could be operating, mediated through the consequences of reduced herd sizes for exposure to predation. Our findings suggest how delays in responding to declining population numbers could prejudice population recovery well before the overall population size drops to levels threatening population viability. [ABSTRACT FROM AUTHOR]

Published
2012
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37. The costs of drinking: comparative water dependency of sable antelope and zebra.

Author

Cain, J. W., Owen-Smith, N., and Macandza, V. A.

Subjects
*ANIMAL ecology, *SABLE antelope, *ZEBRAS, *RESOURCE partitioning (Ecology), *HABITAT selection, *WATER, *SAVANNA animals
Abstract

Resource partitioning among the ungulate species occupying African savanna ecosystems has been well documented in relation to food resources and habitat features, but few studies have addressed how distinctions in surface water dependency contribute to coexistence. During the dry season surface water becomes restricted to a few perennial sources, while the food resources remaining at this time are also most limited in quantity, especially near water where animals congregate to drink. We compared the movement patterns to and from water of sable antelope Hippotragus niger and zebra Equus quagga herds in Kruger National Park (KNP), South Africa. Owing to distinctions in their digestive systems, we expected sable to drink less frequently than zebra, allowing sable to occupy regions further from surface water than zebra. Sable travelled to water at 2-4-day intervals, versus 1-2-day intervals for zebra. However, sable travelled c. 25% greater distances to water due to the location of their late dry season home ranges relative to perennial water sources; zebra home ranges were generally closer to water sources. Travelling 10-15 km to and from water substantially reduced time spent foraging and resting by both species on days when animals drank. Longer intervals between travel to water by the sable antelope herd enabled it to occupy regions of the landscape further from water than those heavily exploited by the more common grazers during the critical dry season months. By avoiding concentrations of other grazers, the sable also probably gained a reduction in predation risk, balancing the substantial costs in terms of time and energy associated with travel to water. Thereby the distinctions in water dependency of this relatively rare grazer facilitated its coexistence alongside more abundant grazers in the KNP. [ABSTRACT FROM AUTHOR]

Published
2012
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39. A scientific perspective on the management of elephants in the Kruger National Park and elsewhere.

Author

Owen-Smith, N., Kerley, G. I. H., Page, B., Slotow, R., and van Aarde, R. J.

Subjects
*ELEPHANTS, *PROBOSCIDEA (Mammals), *BIODIVERSITY, *HABITATS, *SCIENTISTS, *ANIMAL ecology, *WILDLIFE management, *NATIONAL parks & reserves
Abstract

How to respond to growing elephant numbers in the Kruger National Park and elsewhere in southern Africa continues to be a contentious issue. In contrast to the public perception, scientists have attained a high degree of consensus on the ecological basis for such decisions. In this article we summarize these ecological principles and the management responses that are indicated, in order to counter some of the misunderstanding that has been evident in the popular media. [ABSTRACT FROM AUTHOR]

Published
2006

43. Aspects of the breeding biology of the Arrowmarked Babbler Turdoides jardineii in South Africa.

Author

MONADJEM, A., OWEN-SMITH, N., and KEMP, A. C.

Abstract

The breeding success of 18 groups of Arrowmarked Babblers Turdoides jardineii was followed in the 1992-1993 breeding season. The first eggs were laid in late October 1992 and the last eggs in February 1993. Group size was positively correlated with territory size. However, neither group size nor territory size was correlated with the number of offspring raised by a group. Extra adults in a group may not have enhanced the reproductive output of the breeding pair, but they helped in the defence and enlargement of a territory in a saturated habitat. [ABSTRACT FROM AUTHOR]

Published
1995
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