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3. Rethinking megafauna.

Author

Moleón, Marcos, Sánchez-Zapata, José, Donázar, José, Revilla, Eloy, Martín-López, Berta, Gutiérrez-Cánovas, Cayetano, Getz, Wayne, Morales-Reyes, Zebensui, Campos-Arceiz, Ahimsa, Crowder, Larry, Galetti, Mauro, González-Suárez, Manuela, He, Fengzhi, Jordano, Pedro, Lewison, Rebecca, Naidoo, Robin, Owen-Smith, Norman, Selva, Nuria, Svenning, Jens-Christian, Tella, José, Zarfl, Christiane, Jähnig, Sonja, Hayward, Matt, Faurby, Søren, García, Nuria, Barnosky, Anthony, and Tockner, Klement

Subjects
apex predators, body size, functional traits, keystone species, large animals, megaherbivores, Animals, Biological Evolution, Body Size, Conservation of Natural Resources, Extinction, Biological
Abstract

Concern for megafauna is increasing among scientists and non-scientists. Many studies have emphasized that megafauna play prominent ecological roles and provide important ecosystem services to humanity. But, what precisely are megafauna? Here, we critically assess the concept of megafauna and propose a goal-oriented framework for megafaunal research. First, we review definitions of megafauna and analyse associated terminology in the scientific literature. Second, we conduct a survey among ecologists and palaeontologists to assess the species traits used to identify and define megafauna. Our review indicates that definitions are highly dependent on the study ecosystem and research question, and primarily rely on ad hoc size-related criteria. Our survey suggests that body size is crucial, but not necessarily sufficient, for addressing the different applications of the term megafauna. Thus, after discussing the pros and cons of existing definitions, we propose an additional approach by defining two function-oriented megafaunal concepts: keystone megafauna and functional megafauna, with its variant apex megafauna. Assessing megafauna from a functional perspective could challenge the perception that there may not be a unifying definition of megafauna that can be applied to all eco-evolutionary narratives. In addition, using functional definitions of megafauna could be especially conducive to cross-disciplinary understanding and cooperation, improvement of conservation policy and practice, and strengthening of public perception. As megafaunal research advances, we encourage scientists to unambiguously define how they use the term megafauna and to present the logic underpinning their definition.

Published
2020

9. The functional roles of mammals in ecosystems

Author

Lacher, Thomas E., Davidson, Ana D., Fleming, Theodore H., Gómez-Ruiz, Emma P., McCracken, Gary F., Owen-Smith, Norman, Peres, Carlos A., and Vander Wall, Stephen B.

Published
2019

14. Consumer-resource dynamics: quantity, quality, and allocation.

Author

Getz, Wayne M and Owen-Smith, Norman

Subjects
Animals, Humans, Mortality, Ecosystem, Food Chain, Seasons, Population Dynamics, Models, Biological, Models, Biological, General Science & Technology
Abstract

BackgroundThe dominant paradigm for modeling the complexities of interacting populations and food webs is a system of coupled ordinary differential equations in which the state of each species, population, or functional trophic group is represented by an aggregated numbers-density or biomass-density variable. Here, using the metaphysiological approach to model consumer-resource interactions, we formulate a two-state paradigm that represents each population or group in a food web in terms of both its quantity and quality.Methodology and principal findingsThe formulation includes an allocation function controlling the relative proportion of extracted resources to increasing quantity versus elevating quality. Since lower quality individuals senescence more rapidly than higher quality individuals, an optimal allocation proportion exists and we derive an expression for how this proportion depends on population parameters that determine the senescence rate, the per-capita mortality rate, and the effects of these rates on the dynamics of the quality variable. We demonstrate that oscillations do not arise in our model from quantity-quality interactions alone, but require consumer-resource interactions across trophic levels that can be stabilized through judicious resource allocation strategies. Analysis and simulations provide compelling arguments for the necessity of populations to evolve quality-related dynamics in the form of maternal effects, storage or other appropriate structures. They also indicate that resource allocation switching between investments in abundance versus quality provide a powerful mechanism for promoting the stability of consumer-resource interactions in seasonally forcing environments.Conclusions/significanceOur simulations show that physiological inefficiencies associated with this switching can be favored by selection due to the diminished exposure of inefficient consumers to strong oscillations associated with the well-known paradox of enrichment. Also our results demonstrate how allocation switching can explain observed growth patterns in experimental microbial cultures and discuss how our formulation can address questions that cannot be answered using the quantity-only paradigms that currently predominate.

Published
2011

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

Author

KAUFFMAN, MATTHEW J., CAGNACCI, FRANCESCA, CHAMAILLÉ-JAMMES, SIMON, HEBBLEWHITE, MARK J., HOPCRAFT, GRANT C., MERKLE, JEROD A., MUELLER, THOMAS, MYSTERUD, ATLE, PETERS, WIBKE, ROETTGER, CHRISTIANE, STEINGISSER, ALETHEA, MEACHAM, JAMES E., ABERA, KASAHUN, ADAMCZEWSKI, JAN, AIKENS, ELLEN O., BARTLAM-BROOKS, HATTIE, BENNITT, EMILY, BERGER, JOEL, BOYD, CHARLOTTE, CÔTÉ, STEEVE D., DEBEFFE, LUCIE, DEKROUT, ANDREA S., DEJID, NANDINTSETSEG, DONADIO, EMILIANO, DZIBA, LUTHANDO, FAGAN, WILLIAM F., FISCHER, CLAUDE, FOCARDI, STEFANO, FRYXELL, JOHN M., FYNN, RICHARD W. S., GEREMIA, CHRIS, GONZÁLEZ, BENITO A., GUNN, ANNE, GURARIE, ELIE, HEURICH, MARCO, HILTY, JODI, HURLEY, MARK, JOHNSON, ARAN, JOLY, KYLE, KACZENSKY, PETRA, KENDALL, CORINNE J., KOCHKAREV, PAVEL, KOLPASCHIKOV, LEONID, KOWALCZYK, RAFAŁ, LANGEVELDE, FRANK VAN, LI, BINBIN V., LOBORA, ALEX L., LOISON, ANNE, MADIRI, TINAAPI H., MALLON, DAVID, MARCHAND, PASCAL, MEDELLIN, RODRIGO A., MEISINGSET, ERLING, MERRILL, EVELYN, MIDDLETON, ARTHUR D., MONTEITH, KEVIN L., MORJAN, MALIK, MORRISON, THOMAS A., MUMME, STEFFEN, NAIDOO, ROBIN, NOVARO, ANDRES, OGUTU, JOSEPH O., OLSON, KIRK A., OTENG-YEBOAH, ALFRED, OVEJERO, RAMIRO J. A., OWEN-SMITH, NORMAN, PAASIVAARA, ANTTI, PACKER, CRAIG, PANCHENKO, DANILA, PEDROTTI, LUCA, PLUMPTRE, ANDREW J., ROLANDSEN, CHRISTER M., SAID, SONIA, SALEMGAREYEV, ALBERT, SAVCHENKO, ALEKSANDR, SAVCHENKO, PIOTR, SAWYER, HALL, SELEBATSO, MOSES, SKROCH, MATTHEW, SOLBERG, ERLING, STABACH, JARED A., STRAND, OLAV, SUITOR, MICHAEL J., TACHIKI, YASUYUKI, TRAINOR, ANNE, TSHIPA, ARNOLD, VIRANI, MUNIR Z., VYNNE, CARLY, WARD, STEPHANIE, WITTEMYER, GEORGE, XU, WENJING, ZUTHER, STEFFEN, KAUFFMAN, MATTHEW J., CAGNACCI, FRANCESCA, CHAMAILLÉ-JAMMES, SIMON, HEBBLEWHITE, MARK J., HOPCRAFT, GRANT C., MERKLE, JEROD A., MUELLER, THOMAS, MYSTERUD, ATLE, PETERS, WIBKE, ROETTGER, CHRISTIANE, STEINGISSER, ALETHEA, MEACHAM, JAMES E., ABERA, KASAHUN, ADAMCZEWSKI, JAN, AIKENS, ELLEN O., BARTLAM-BROOKS, HATTIE, BENNITT, EMILY, BERGER, JOEL, BOYD, CHARLOTTE, CÔTÉ, STEEVE D., DEBEFFE, LUCIE, DEKROUT, ANDREA S., DEJID, NANDINTSETSEG, DONADIO, EMILIANO, DZIBA, LUTHANDO, FAGAN, WILLIAM F., FISCHER, CLAUDE, FOCARDI, STEFANO, FRYXELL, JOHN M., FYNN, RICHARD W. S., GEREMIA, CHRIS, GONZÁLEZ, BENITO A., GUNN, ANNE, GURARIE, ELIE, HEURICH, MARCO, HILTY, JODI, HURLEY, MARK, JOHNSON, ARAN, JOLY, KYLE, KACZENSKY, PETRA, KENDALL, CORINNE J., KOCHKAREV, PAVEL, KOLPASCHIKOV, LEONID, KOWALCZYK, RAFAŁ, LANGEVELDE, FRANK VAN, LI, BINBIN V., LOBORA, ALEX L., LOISON, ANNE, MADIRI, TINAAPI H., MALLON, DAVID, MARCHAND, PASCAL, MEDELLIN, RODRIGO A., MEISINGSET, ERLING, MERRILL, EVELYN, MIDDLETON, ARTHUR D., MONTEITH, KEVIN L., MORJAN, MALIK, MORRISON, THOMAS A., MUMME, STEFFEN, NAIDOO, ROBIN, NOVARO, ANDRES, OGUTU, JOSEPH O., OLSON, KIRK A., OTENG-YEBOAH, ALFRED, OVEJERO, RAMIRO J. A., OWEN-SMITH, NORMAN, PAASIVAARA, ANTTI, PACKER, CRAIG, PANCHENKO, DANILA, PEDROTTI, LUCA, PLUMPTRE, ANDREW J., ROLANDSEN, CHRISTER M., SAID, SONIA, SALEMGAREYEV, ALBERT, SAVCHENKO, ALEKSANDR, SAVCHENKO, PIOTR, SAWYER, HALL, SELEBATSO, MOSES, SKROCH, MATTHEW, SOLBERG, ERLING, STABACH, JARED A., STRAND, OLAV, SUITOR, MICHAEL J., TACHIKI, YASUYUKI, TRAINOR, ANNE, TSHIPA, ARNOLD, VIRANI, MUNIR Z., VYNNE, CARLY, WARD, STEPHANIE, WITTEMYER, GEORGE, XU, WENJING, and ZUTHER, STEFFEN

Abstract

type:Article

Published
2023

24. Spatial patterns of large African cats : a large-scale study on density, home range size, and home range overlap of lions Panthera leo and leopards Panthera pardus

Author

Nams, Vilis O., Parker, Dan M., Weise, Florian J., Patterson, Bruce D., Buij, Ralph, Radloff, Frans G.T., Vanak, Abi Tamim, Tumenta, Pricelia N., Hayward, Matt W., Swanepoel, Lourens H., Funston, Paul J., Bauer, Hans, Power, R.J., O'Brien, John, O'Brien, Timothy G., Tambling, Craig J., de Iongh, Hans H., Ferreira, Sam M., Owen-Smith, Norman, Cain, James W., Fattebert, Julien, Croes, Barbara M., Spong, Goran, Loveridge, Andrew J., Houser, Ann Marie, Golabek, Krystyna A., Begg, Colleen M., Grant, Tanith, Trethowan, Paul, Musyoki, Charles, Menges, Vera, Creel, Scott, Balme, Guy A., Pitman, Ross T., Bissett, Charlene, Jenny, David, Schuette, Paul, Wilmers, Christopher C., Hunter, Luke T.B., Kinnaird, Margaret F., Begg, Keith S., Owen, Cailey R., Steyn, Villiers, Bockmuehl, Dirk, Munro, Stuart J., Mann, Gareth K.H., du Preez, Byron D., Marker, Laurie L., Huqa, Tuqa J., Cozzi, Gabriele, Frank, Laurence G., Nyoni, Phumuzile, Stein, Andrew B., Kasiki, Samuel M., Macdonald, David W., Martins, Quinton E., van Vuuren, Rudie J., Stratford, Ken J., Bidner, Laura R., Oriol-Cotteril, Alayne, Maputla, Nakedi W., Maruping-Mzileni, Nkabeng, Parker, Tim, van't Zelfde, Maarten, Isbell, Lynne A., Beukes, Otto B., Beukes, Maya, Nams, Vilis O., Parker, Dan M., Weise, Florian J., Patterson, Bruce D., Buij, Ralph, Radloff, Frans G.T., Vanak, Abi Tamim, Tumenta, Pricelia N., Hayward, Matt W., Swanepoel, Lourens H., Funston, Paul J., Bauer, Hans, Power, R.J., O'Brien, John, O'Brien, Timothy G., Tambling, Craig J., de Iongh, Hans H., Ferreira, Sam M., Owen-Smith, Norman, Cain, James W., Fattebert, Julien, Croes, Barbara M., Spong, Goran, Loveridge, Andrew J., Houser, Ann Marie, Golabek, Krystyna A., Begg, Colleen M., Grant, Tanith, Trethowan, Paul, Musyoki, Charles, Menges, Vera, Creel, Scott, Balme, Guy A., Pitman, Ross T., Bissett, Charlene, Jenny, David, Schuette, Paul, Wilmers, Christopher C., Hunter, Luke T.B., Kinnaird, Margaret F., Begg, Keith S., Owen, Cailey R., Steyn, Villiers, Bockmuehl, Dirk, Munro, Stuart J., Mann, Gareth K.H., du Preez, Byron D., Marker, Laurie L., Huqa, Tuqa J., Cozzi, Gabriele, Frank, Laurence G., Nyoni, Phumuzile, Stein, Andrew B., Kasiki, Samuel M., Macdonald, David W., Martins, Quinton E., van Vuuren, Rudie J., Stratford, Ken J., Bidner, Laura R., Oriol-Cotteril, Alayne, Maputla, Nakedi W., Maruping-Mzileni, Nkabeng, Parker, Tim, van't Zelfde, Maarten, Isbell, Lynne A., Beukes, Otto B., and Beukes, Maya

Abstract

Spatial patterns of and competition for resources by territorial carnivores are typically explained by two hypotheses: 1) the territorial defence hypothesis and 2) the searching efficiency hypothesis. According to the territorial defence hypothesis, when food resources are abundant, carnivore densities will be high and home ranges small. In addition, carnivores can maximise their necessary energy intake with minimal territorial defence. At medium resource levels, larger ranges will be needed, and it will become more economically beneficial to defend resources against a lower density of competitors. At low resource levels, carnivore densities will be low and home ranges large, but resources will be too scarce to make it beneficial to defend such large territories. Thus, home range overlap will be minimal at intermediate carnivore densities. According to the searching efficiency hypothesis, there is a cost to knowing a home range. Larger areas are harder to learn and easier to forget, so carnivores constantly need to keep their cognitive map updated by regularly revisiting parts of their home ranges. Consequently, when resources are scarce, carnivores require larger home ranges to acquire sufficient food. These larger home ranges lead to more overlap among individuals' ranges, so that overlap in home ranges is largest when food availability is the lowest. Since conspecific density is low when food availability is low, this hypothesis predicts that overlap is largest when densities are the lowest. We measured home range overlap and used a novel method to compare intraspecific home range overlaps for lions Panthera leo (n = 149) and leopards Panthera pardus (n = 111) in Africa. We estimated home range sizes from telemetry location data and gathered carnivore density data from the literature. Our results did not support the territorial defence hypothesis for either species. Lion prides increased their home range overlap at conspecific lower densities whereas leopards did

Published
2023

25. Spatial patterns of large African cats: a large‐scale study on density, home range size, and home range overlap of lions Panthera leo and leopards Panthera pardus

Author

Nams, Vilis O., primary, Parker, Dan M., additional, Weise, Florian J., additional, Patterson, Bruce D., additional, Buij, Ralph, additional, Radloff, Frans G. T., additional, Vanak, Abi Tamim, additional, Tumenta, Pricelia N., additional, Hayward, Matt W., additional, Swanepoel, Lourens H., additional, Funston, Paul J., additional, Bauer, Hans, additional, Power, R. John, additional, O'Brien, John, additional, O'Brien, Timothy G., additional, Tambling, Craig J., additional, de Iongh, Hans H., additional, Ferreira, Sam M., additional, Owen‐Smith, Norman, additional, Cain, James W., additional, Fattebert, Julien, additional, Croes, Barbara M., additional, Spong, Goran, additional, Loveridge, Andrew J., additional, Houser, Ann Marie, additional, Golabek, Krystyna A., additional, Begg, Colleen M., additional, Grant, Tanith, additional, Trethowan, Paul, additional, Musyoki, Charles, additional, Menges, Vera, additional, Creel, Scott, additional, Balme, Guy A., additional, Pitman, Ross T., additional, Bissett, Charlene, additional, Jenny, David, additional, Schuette, Paul, additional, Wilmers, Christopher C., additional, Hunter, Luke T. B., additional, Kinnaird, Margaret F., additional, Begg, Keith S., additional, Owen, Cailey R., additional, Steyn, Villiers, additional, Bockmuehl, Dirk, additional, Munro, Stuart J., additional, Mann, Gareth K. H., additional, du Preez, Byron D., additional, Marker, Laurie L., additional, Huqa, Tuqa J., additional, Cozzi, Gabriele, additional, Frank, Laurence G., additional, Nyoni, Phumuzile, additional, Stein, Andrew B., additional, Kasiki, Samuel M., additional, Macdonald, David W., additional, Martins, Quinton E., additional, van Vuuren, Rudie J., additional, Stratford, Ken J., additional, Bidner, Laura R., additional, Oriol‐Cotteril, Alayne, additional, Maputla, Nakedi W., additional, Maruping‐Mzileni, Nkabeng, additional, Parker, Tim, additional, van't Zelfde, Maarten, additional, Isbell, Lynne A., additional, Beukes, Otto B., additional, and Beukes, Maya, additional

Published
2023
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