Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
J Anim Ecol ; 93(2): 159-170, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38174381

RESUMO

Animal social and spatial behaviours are inextricably linked. Animal movements are driven by environmental factors and social interactions. Habitat structure and changing patterns of animal space use can also shape social interactions. Animals adjust their social and spatial behaviours to reduce the risk of offspring mortality. In territorial infanticidal species, two strategies are possible for males: they can stay close to offspring to protect them against rivals (infant-defence hypothesis) or patrol the territory more intensively to prevent rival intrusions (territorial-defence hypothesis). Here, we tested these hypotheses in African lions (Panthera leo) by investigating how males and females adjust their social and spatial behaviours in the presence of offspring. We combined datasets on the demography and movement of lions, collected between 2002 and 2016 in Hwange National Park (Zimbabwe), to document the presence of cubs (field observations) and the simultaneous movements of groupmates and competitors (GPS tracking). We showed a spatial response of lions to the presence of offspring, with females with cubs less likely to select areas close to waterholes or in the periphery of the territory than females without cubs. In contrast, these areas were more selected by males when there were cubs in the pride. We also found social responses. Males spent more time with females as habitat openness increased but the presence of cubs in the pride did not influence the average likelihood of observing males with females. Furthermore, rival males relocated further after an encounter with pride males when cubs were present in the prides, suggesting that the presence of cubs leads to a more vigorous repulsion of competitors. Males with cubs in their pride were more likely to interact with male competitors on the edge of the pride's home range and far from the waterholes, suggesting that they are particularly assiduous in detecting and repelling rival males during these periods. In general, the strategies to avoid infanticide exhibited by male lions supported the territorial-defence hypothesis. Our study contributes to answer the recent call for a behavioural ecology at the spatial-social interface.


Assuntos
Leões , Interação Social , Humanos , Feminino , Masculino , Animais , Leões/fisiologia , Infanticídio , Territorialidade , Ecossistema
2.
Conserv Biol ; 35(4): 1233-1244, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33294987

RESUMO

Conflict with humans is one of the major threats facing the world's remaining large carnivore populations, and understanding human attitudes is key to improving coexistence. We surveyed people living near Hwange National Park about their attitudes toward coexisting with lions. We used ordinal regression models with the results of the survey to investigate the importance of a range of tangible and intangible factors on attitudes. The variables investigated included the costs and benefits of wildlife presence, emotion, culture, religion, vulnerability, risk perception, notions of responsibility, and personal value orientations. This was for the purpose of effectively tailoring conservation efforts but also for ethical policy making. Intangible factors (e.g., fear and ecocentric values) were as important as, if not more important than, tangible factors (such as livestock losses) for understanding attitudes, based on the effect sizes of these variables. The degree to which participants' fear of lions interfered with their daily activities was the most influential variable. The degree to which benefits accrue to households from the nearby protected area was also highly influential, as was number of livestock lost, number of dependents, ecocentric value orientation, and participation in conflict mitigation programs. Contrary to what is often assumed, metrics of livestock loss did not dominate attitudes to coexistence with lions. Furthermore, we found that socioeconomic variables may appear important when studied in isolation, but their effect may disappear when controlling for variables related to beliefs, perceptions, and past experiences. This raises questions about the widespread reliance on socioeconomic variables in the field of human-wildlife conflict and coexistence. To facilitate coexistence with large carnivores, we recommend measures that reduce fear (through education and through protective measures that reduce the need to be fearful), reduction of livestock losses, and ensuring local communities benefit from conservation. Ecocentric values also emerged as influential, highlighting the need to develop conservation initiatives tailored to local values.


Importancia de los Factores Tangibles e Intangibles en la Coexistencia Humanos-Carnívoros Resumen Los conflictos con humanos son una de las principales amenazas que enfrentan las poblaciones permanentes de grandes carnívoros del planeta y el entendimiento de las actitudes humanas es importante para mejorar la coexistencia. Preguntamos a las personas que viven cerca del Parque Nacional Hwange sobre su postura hacia la coexistencia con leones. Usamos modelos de regresión ordinal en los resultados del cuestionario para investigar la importancia de una gama de factores tangibles e intangibles para estas posturas. Las variables investigadas incluyeron el costo y beneficio de la presencia de fauna, emociones, cultura, religión, vulnerabilidad, percepción de riesgos, nociones de la responsabilidad y orientaciones de valor personal. Realizamos esto con el propósito de diseñar efectivamente los esfuerzos de conservación pero también para la generación de políticas éticas. Los factores intangibles (p. ej.: el miedo y los valores ecocéntricos) fueron tan importantes, si no es que más importantes, como los factores tangibles (como la pérdida de cabezas de ganado) para el entendimiento de las actitudes, con base en los tamaños del efecto de estas variables. El grado al que el miedo que los participantes sienten por los leones interfiere con sus actividades diarias fue la variable con mayor influencia. El grado al que los hogares del área protegida cercana devengan beneficios también tuvo una influencia alta, como lo tuvo el número de cabezas de ganado perdidas, el número de dependientes, la orientación de los valores ecocéntricos y la participación en programas de mitigación del conflicto. Contrario a lo que frecuentemente se asume, las medidas de la pérdida de cabezas de ganado no dominó sobre las actitudes por la coexistencia con leones. Más allá, encontramos que las variables socioeconómicas pueden parecer importantes cuando se estudian de manera aislada pero su efecto puede desaparecer cuando se controlan las variables relacionadas con las creencias, percepciones y experiencias pasadas. Esto genera preguntas sobre la dependencia hacia las variables socioeconómicas en el área de estudios de conflictos y coexistencia entre humanos y fauna. Para facilitar la coexistencia con carnívoros mayores recomendamos tomar medidas que reduzcan el miedo (por medio de la educación y medidas de protección que reduzcan la necesidad de vivir con miedo), la disminución de la pérdida de cabezas de ganado y garantizarles a las comunidades locales los beneficios que proporciona la conservación. Los valores ecocéntricos también surgieron como influyentes, lo que resalta la necesidad de desarrollar iniciativas de conservación adaptadas a los valores locales.


Assuntos
Carnívoros , Leões , Animais , Animais Selvagens , Conservação dos Recursos Naturais , Humanos , Gado
3.
Proc Natl Acad Sci U S A ; 115(45): E10788-E10796, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30348785

RESUMO

Protected areas (PAs) play an important role in conserving biodiversity and providing ecosystem services, yet their effectiveness is undermined by funding shortfalls. Using lions (Panthera leo) as a proxy for PA health, we assessed available funding relative to budget requirements for PAs in Africa's savannahs. We compiled a dataset of 2015 funding for 282 state-owned PAs with lions. We applied three methods to estimate the minimum funding required for effective conservation of lions, and calculated deficits. We estimated minimum required funding as $978/km2 per year based on the cost of effectively managing lions in nine reserves by the African Parks Network; $1,271/km2 based on modeled costs of managing lions at ≥50% carrying capacity across diverse conditions in 115 PAs; and $2,030/km2 based on Packer et al.'s [Packer et al. (2013) Ecol Lett 16:635-641] cost of managing lions in 22 unfenced PAs. PAs with lions require a total of $1.2 to $2.4 billion annually, or ∼$1,000 to 2,000/km2, yet received only $381 million annually, or a median of $200/km2 Ninety-six percent of range countries had funding deficits in at least one PA, with 88 to 94% of PAs with lions funded insufficiently. In funding-deficit PAs, available funding satisfied just 10 to 20% of PA requirements on average, and deficits total $0.9 to $2.1 billion. African governments and the international community need to increase the funding available for management by three to six times if PAs are to effectively conserve lions and other species and provide vital ecological and economic benefits to neighboring communities.


Assuntos
Conservação dos Recursos Naturais/economia , Leões/fisiologia , Modelos Estatísticos , África , Animais , Conservação dos Recursos Naturais/legislação & jurisprudência , Conjuntos de Dados como Assunto , Ecossistema
4.
J Anim Ecol ; 89(11): 2665-2676, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32895921

RESUMO

Environmental variations can influence the extent to which individuals interact with other individuals by changing the value of grouping. It is well known that many species can form and disband groups, often in response to the distribution and abundance of resources. While previous studies showed that resources influence the broad-scale structure of animal groups, knowledge gaps remain on whether they affect fine-scale patterns of association among individuals within groups. We quantify association patterns in African lions while simultaneously monitoring the abundance and distribution of prey. We test how social and ecological factors, including individual trait (age, sex, reproductive state) similarity and prey availability (prey abundance, dispersion, herd size and body size) affect within-pride social structure in African lions. We found that individual decisions about associates depended on resource availability with individuals associating equally across all members of the pride when prey herds were scarce, aggregated or large bodied, and associating more exclusively (in subgroups of preferred associates) when prey herds were abundant, dispersed or small bodied. Individuals within lion prides seemed to be buffering against changes in prey availability by modulating their strength and density of connections with conspecifics when prides split into subgroups. The strength and density of connections among individuals within subgroups was greater when prey herds were large and lower when prey herds were dispersed or are large bodied. Our findings suggest that individual lions are making social decisions at both the subgroup level and the pride level, with decisions representing putatively fitness-enhancing strategies. Individuals were typically shifting between having few strong connections and having many weaker connections depending on prevailing ecological conditions, with prey abundance, dispersion and body size having the greatest impact on decisions about splitting into subgroups. The maintenance of connections within prides and subgroups in the face of ecological change suggests that the fission-fusion nature of lion prides might be essential for the long-term maintenance of social connections even when short-term conditions do not allow them. More broadly, our study reveals how fission-fusion dynamics and ecological factors can simultaneously have an effect on animals across multiple levels of sociality.


Assuntos
Leões , Animais , Comportamento Predatório , Reprodução , Comportamento Social
5.
Conserv Biol ; 34(4): 879-890, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32406971

RESUMO

Conflict between people and carnivores can lead to the widespread killing of predators in retaliation for livestock loss and is a major threat to predator populations. In Kenya, a large, rural, pastoralist population comes into regular conflict with predators, which persist across southern Kenya. We explored the social and psychological backdrop to livestock management practices in this area in a process designed to be easy to use and suitable for use across large areas for the study of conflict and transboundary implementation of wildlife conflict reduction measures, focusing on community involvement and needs. We carried out fully structured interviews of livestock managers with a survey tool that examined how social and psychological factors may influence livestock management behavior. We compared survey responses on 3 sites across the study area, resulting in 723 usable responses. Efficacy of individuals' livestock management varied between and within communities. This variation was partially explained by normative and control beliefs regarding livestock management. Individual livestock managers' self-reported management issues were often an accurate reflection of their practical management difficulties. Psychological norms, control beliefs, and attitudes differed among sites, and these differences partially explained patterns associated with conflict (i.e., variation in livestock management behavior). Thus, we conclude that a one-size-fits-all approach to improving livestock management and reducing human-predator conflict is not suitable.


El Papel de la Psicología en la Determinación del Conflicto Humano - Depredador en el sur de Kenia Resumen El conflicto entre las personas y los carnívoros puede derivar en la cacería extendida de los depredadores como consecuencia de la pérdida del ganado, además de ser una amenaza importante para las poblaciones de depredadores. En Kenia, una gran población rural y pastora entra en conflicto regularmente con los depredadores, que son muy comunes en el sur del país. Exploramos el trasfondo social y psicológico de las prácticas de manejo de ganado en esta área en un proceso diseñado para ser fácil de usar y adecuado para grandes áreas para el estudio del conflicto y la implementación transfronteriza de medidas de reducción del conflicto con la fauna. Nos enfocamos particularmente en las necesidades y en la participación de la comunidad. Realizamos entrevistas estructuradas a los manejadores del ganado con una herramienta de censo que examinó cómo los factores psicológicos y sociales pueden influir sobre el comportamiento del manejador del ganado. Comparamos las respuestas del censo en tres sitios del área de estudio, lo que resultó en 723 respuestas útiles. La efectividad del manejo de ganado realizado por los individuos varió entre y dentro de las comunidades. Esta variación estuvo explicada parcialmente por las creencias normativas y de control en relación al manejo del ganado. Los temas de manejo reportados por los mismos manejadores individuales de ganado casi siempre fueron un reflejo acertado de sus complicaciones prácticas en el manejo. Las normas psicológicas, las creencias de control y las actitudes difirieron entre sitios, y estas diferencias explicaron parcialmente los patrones asociados con el conflicto (es decir, la variación en el comportamiento del manejador del ganado). Por lo tanto, concluimos que una estrategia igual-para-todos para mejorar el manejo del ganado y reducir el conflicto humano - depredador no es la adecuada.


Assuntos
Carnívoros , Conservação dos Recursos Naturais , Animais , Animais Selvagens , Humanos , Quênia , Gado , Comportamento Predatório
6.
Oecologia ; 192(3): 779-789, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32060732

RESUMO

In large mammal communities, little is known about modification of interspecific interactions through habitat structure changes. We assessed the effects of African elephants (Loxodonta africana) on features of woody habitat structure that can affect predator-prey interactions. We then explored how this can influence where African lions (Panthera leo) kill their prey. Indeed, lions are stalk-and-ambush predators and habitat structure and concealment opportunities are assumed to influence their hunting success. During 2 years, in Hwange National Park, Zimbabwe, kill sites (n = 167) of GPS-collared lions were characterized (visibility distance for large mammals, distance to a potential ambush site and presence of elephant impacts). We compared characteristics of lion kill sites with characteristics of random sites (1) at a large scale (i.e. in areas intensively used by lions, n = 418) and (2) at the microhabitat scale (i.e. in the direct surrounding available habitat, < 150 m, n = 167). Elephant-impacted sites had a slightly higher visibility and a longer distance to a potential ambush site than non-impacted sites, but these relationships were characterized by a high variability. At large scale, kill sites were characterized by higher levels of elephant impacts compared to random sites. At microhabitat scale, compared to the direct nearby available habitat, kill sites were characterized by a reduced distance to a potential ambush site. We suggest a conceptual framework whereby the relative importance of habitat features and prey abundance could change upon the scale considered.


Assuntos
Herbivoria , Leões , Animais , Ecossistema , Meio Ambiente , Comportamento Predatório
7.
J Anim Ecol ; 88(1): 92-101, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30280384

RESUMO

Diel migrations (DM; back and forth diel movements along an ecological gradient) undertaken by prey to avoid predators during the day have been demonstrated in many taxa in aquatic ecosystems. In terrestrial ecosystems, prey often shift between various vegetation types whose cover determine their vulnerability (i.e., likelihood of being killed when attacked). We conceptualized that in terrestrial ecosystems, DM could also occur and that the contribution of DM and shifts in vegetation cover use in reducing predation risk should depend upon the predator behaviour and the correlation between encounter risk and vulnerability across vegetation types. We further hypothesized that when the predator distribution is predictable, terrestrial prey could have evolved DM strategies taking them away from the predator when it is active or efficient. We investigated whether plains zebras Equus quagga perform DM in Hwange National Park (Zimbabwe). There, zebras can forage in large patches of open grasslands located near waterholes where they can also easily detect predators. However, they are there at high risk of encountering their main predator, lions Panthera leo, especially at night. We found out that zebras employ a DM anti-predator strategy. Zebras forage near waterholes during the day but move away from them at sunset, when lions become active. We demonstrated that this DM, occurring over a few kilometres, dramatically reduces their night-time risk of encountering lions, which generally remain close to waterholes. Zebra changes in night-time selection for vegetation cover types reduced their risk of encountering lions much less. This may arise from a trade-off between encounter risk and vulnerability across vegetation types, with zebras favouring low vulnerability once DM has reduced encounter risk. In summary, here we (a) quantify, in a terrestrial system, the effect of a predator-induced DM on the likelihood of encountering a predator and (b) distinguish the effects of the DM on encounter risk from those related to day/night changes in selection for vegetation types. We discuss how prey partition their risk between encounter risk and habitat-driven vulnerability and why it is likely critical to understand the emergence of anti-predator behavioural strategies.


Assuntos
Leões , Animais , Ecossistema , Equidae , Comportamento Predatório , Zimbábue
8.
Biol Lett ; 12(11)2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27881765

RESUMO

Mammals use endogenously produced heat to maintain a high and relatively constant core body temperature (Tb). How they regulate their Tb during reproduction might inform us as to what thermal conditions are necessary for optimal development of offspring. However, few studies have measured Tb in free-ranging animals for sufficient periods of time to encounter reproductive events. We measured Tb continuously in six free-ranging adult female African lions (Panthera leo) for approximately 1 year. Lions reduced the 24 h amplitude of Tb by about 25% during gestation and decreased mean 24 h Tb by 1.3 ± 0.1°C over the course of the gestation, reducing incidences of hyperthermia (Tb > 39.5°C). The observation of improved homeothermy during reproduction may support the parental care model (PCM) for the evolution of endothermy, which postulates that endothermy arose in birds and mammals as a consequence of more general selection for parental care. According to the PCM, endothermy arose because it enabled parents to better control incubation temperature, leading to rapid growth and development of offspring and thus to fitness benefits for the parents. Whether the precision of Tb regulation in pregnant lions, and consequently their reproductive success, will be influenced by changing environmental conditions, particularly hotter and drier periods associated with climate change, remains to be determined.


Assuntos
Leões/fisiologia , Prenhez/fisiologia , Termogênese/fisiologia , Animais , Feminino , Gravidez
9.
Proc Biol Sci ; 281(1785): 20140446, 2014 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-24789903

RESUMO

Predators influence prey populations not only through predation itself, but also indirectly through prompting changes in prey behaviour. The behavioural adjustments of prey to predation risk may carry nutritional costs, but this has seldom been studied in the wild in large mammals. Here, we studied the effects of an ambush predator, the African lion (Panthera leo), on the diet quality of plains zebras (Equus quagga) in Hwange National Park, Zimbabwe. We combined information on movements of both prey and predators, using GPS data, and measurements of faecal crude protein, an index of diet quality in the prey. Zebras which had been in close proximity to lions had a lower quality diet, showing that adjustments in behaviour when lions are within short distance carry nutritional costs. The ultimate fitness cost will depend on the frequency of predator-prey encounters and on whether bottom-up or top-down forces are more important in the prey population. Our finding is the first attempt to our knowledge to assess nutritionally mediated risk effects in a large mammalian prey species under the threat of an ambush predator, and brings support to the hypothesis that the behavioural effects of predation induce important risk effects on prey populations.


Assuntos
Dieta , Equidae/fisiologia , Leões/fisiologia , Comportamento Predatório , Fenômenos Fisiológicos da Nutrição Animal , Animais , Comportamento Alimentar , Feminino , Masculino , Zimbábue
10.
Ecol Evol ; 14(3): e11141, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38500850

RESUMO

Predators of similar size often compete over prey. In semi-arid ecosystems where water is a limiting resource, prey availability can be affected by water distribution, which further increases resource competition and exacerbate conflict among predators. This can have implications for carnivore dietary competition. Hence, we evaluated the dynamics of food resource competition between African wild dogs and four competing predators (cheetahs, leopards, lions and spotted hyaenas) in different seasons and across areas with different waterhole densities in Hwange National Park, Zimbabwe. We used the frequency of occurrence of prey items found in predators' scats to analyse diet composition, overlap and prey preference. For most predators, kudu was most frequently consumed and preferred. Low and medium water-dependent prey (medium and small-sized) were mostly consumed by wild dogs, leopards and cheetahs. Wild dog diet overlap was high with all predators, particularly with hyaenas and lions. There were no seasonal differences in the predators diet. The diet overlap of wild dogs with lions was highest in the low waterhole density area, and wild dog diet composition did not differ significantly from the diet of lions and hyaenas. In the low waterhole density area, wild dogs and hyaenas broadened their niche breadth, and predators diet had a higher proportion of low water-dependent prey. A low density of waterholes increased food resource competition. However, high density of waterholes, where there is more prey availability, can increase the aggregation and density of predators, and hence, increase the risks involved in interspecific competition on wild dogs. To reduce food resource competition on wild dogs, we propose to conserve larger-bodied prey that are less dependent on water (e.g. kudu, reedbuck, eland and gemsbok). As the use of water pumping is common practice, we propose maintaining water management heterogeneity where prey which is less dependent on water can also thrive.

11.
Sci Rep ; 13(1): 95, 2023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36635294

RESUMO

Many large predator populations are in decline globally with significant implications for ecosystem integrity and function. Understanding the drivers of their decline is required to adequately mitigate threats. Trophy hunting is often cited as a tool to conserve large mammal populations but may also have negative impacts if not well managed. Here we use a spatially implicit, individual based model to investigate the threats posed to African lion populations by poorly managed trophy hunting and additive anthropogenic mortality such as poaching and retaliatory killing. We confirm the results of previous studies that show that lion trophy hunting can be sustainable if only older male lions are hunted, but demonstrate that hunting becomes unsustainable when populations are exposed to additional anthropogenic mortality, as is the case for most free ranging populations. We show that edge effects can be a critical determinant of population viability and populations that encompass well protected source areas are more robust than those without. Finally, errors in aging of hunted lions by professional trophy hunters may undermine the sustainability of the age-based quota setting strategies that are now widely used to manage lion trophy hunting. The effect of aging errors was most detrimental to population persistence in the ≥ 6 and ≥ 7 year-old age thresholds that are frequently used to define suitably aged lions for hunting. Resource managers should limit offtakes to older demographics and additionally take a precautionary approach when setting hunting quotas for large carnivore populations that are affected by other sources of anthropogenic mortality, such as bush-meat poaching, retaliatory killing and problem animal control.


Assuntos
Leões , Animais , Masculino , Conservação dos Recursos Naturais/métodos , Caça , Ecossistema , Envelhecimento
12.
Ecology ; 93(11): 2490-6, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23236920

RESUMO

Empirical tests of the resource dispersion hypothesis (RDH), a theory to explain group living based on resource heterogeneity, have been complicated by the fact that resource patch dispersion and richness have proved difficult to define and measure in natural systems. Here, we studied the ecology of African lions Panthera leo in Hwange National Park, Zimbabwe, where waterholes are prey hotspots, and where dispersion of water sources and abundance of prey at these water sources are quantifiable. We combined a 10-year data set from GPS-collared lions for which information of group composition was available concurrently with data for herbivore abundance at waterholes. The distance between two neighboring waterholes was a strong determinant of lion home range size, which provides strong support for the RDH prediction that territory size increases as resource patches are more dispersed in the landscape. The mean number of herbivore herds using a waterhole, a good proxy of patch richness, determined the maximum lion group biomass an area can support. This finding suggests that patch richness sets a maximum ceiling on lion group size. This study demonstrates that landscape ecology is a major driver of ranging behavior and suggests that aspects of resource dispersion limit group sizes.


Assuntos
Ecossistema , Herbivoria/fisiologia , Leões/fisiologia , Territorialidade , Animais , Artiodáctilos , Demografia , Elefantes , Equidae , Feminino , Masculino , Modelos Biológicos
13.
Am Nat ; 178(2): 269-75, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21750389

RESUMO

We test two hypotheses that could account for patch departure by large mammalian carnivores. One hypothesis is the unsuccessful-hunt hypothesis, where carnivores leave an area after an unsuccessful hunt but continue hunting in the same area after a successful hunt. The second hypothesis is the patch-disturbance hypothesis, where carnivores depart the area after a successful hunt because of behavioral responses of prey to predator presence. We used global positioning system collars to monitor the movements of African lions (Panthera leo) and identified their kill sites to distinguish between these two hypotheses. Lions moved to a different area (≥ 5 km away) after 87% of the kills, which supports the patch-disturbance hypothesis for patch-departure behavior of large mammalian carnivores.


Assuntos
Leões/fisiologia , Comportamento Predatório , Animais , Feminino , Sistemas de Informação Geográfica , Comportamento de Retorno ao Território Vital , Masculino , Zimbábue
14.
Soc Stud Sci ; 51(1): 73-99, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32865131

RESUMO

Research in theoretical quantum gravity has continued expansively even as it has become detached from classic arbiters of research such as direct empirical falsification. This makes it an interesting test case for theories of what motivates and mediates contemporary scientific research and of the nature of scientific objectivity. We conducted 50 semi-structured interviews with researchers in the rival camps of string theory and loop quantum gravity, coded a subset for reoccurring themes, and subjected the resulting data to statistical analysis. To delineate the subjective tastes and the related process of collective consensus-making in contemporary quantum gravity research, we mobilize aspects of Daston and Galison's depiction of the scientific self and its relation to epistemic virtues, Bourdieu's field-centered account of social space, and Kantian notions of aesthetics. We make two key contributions. First, our analysis sheds light on the inner workings of the field by connecting its internal epistemic struggles with approaches to understanding scientific fields. Second, our application of theories of social reproduction to the substance of scientific inquiry allows some substantive generalizations of Daston and Galison's framework.


Assuntos
Teoria Quântica , Gravitação
15.
PLoS One ; 16(9): e0256876, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34506529

RESUMO

Africa is home to some of the world's most functionally diverse guilds of large carnivores. However, they are increasingly under threat from anthropogenic pressures that may exacerbate already intense intra-guild competition. Understanding the coexistence mechanisms employed by these species in human-impacted landscapes could help shed light on some of the more subtle ways in which humans may impact wildlife populations, and inform multi-species conservation planning. We used camera trap data from Tanzania's Ruaha-Rungwa landscape to explore temporal and spatiotemporal associations between members of an intact East African large carnivore guild, and determine how these varied across gradients of anthropogenic impact and protection. All large carnivores except African wild dog (Lycaon pictus) exhibited predominantly nocturnal road-travel behaviour. Leopard (Panthera pardus) appeared to employ minor temporal avoidance of lion (Panthera leo) in all sites except those where human impacts were highest, suggesting that leopard may have been freed up from avoidance of lion in areas where the dominant competitor was less abundant, or that the need for leopard to avoid humans outweighed the need to avoid sympatric competitors. Lion appeared to modify their activity patterns to avoid humans in the most impacted areas. We also found evidence of avoidance and attraction among large carnivores: lion and spotted hyaena (Crocuta crocuta) followed leopard; leopard avoided lion; spotted hyaena followed lion; and lion avoided spotted hyaena. Our findings suggest that large carnivores in Ruaha-Rungwa employ fine-scale partitioning mechanisms to facilitate coexistence with both sympatric species and humans, and that growing human pressures may interfere with these behaviours.


Assuntos
Animais Selvagens , Carnívoros , Conservação dos Recursos Naturais/métodos , Ecossistema , Animais , Humanos , Tanzânia
16.
Transbound Emerg Dis ; 68(3): 1676-1684, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32964687

RESUMO

Numerous unknown factors influence anthrax epidemiology in multi-host systems, especially at wildlife/livestock/human interfaces. Serology tests for anti-anthrax antibodies in carnivores are useful tools in identifying the presence or absence of Bacillus anthracis in a range. These were employed to ascertain whether the disease pattern followed the recognized high- and low-risk anthrax zonation in Zimbabwe and also to establish whether anthrax was absent from Hwange National Park in which there have been no reported outbreaks. African lions (Panthera leo) (n = 114) drawn from free-range protected areas and captive game parks located in recognized high- and low-risk zones across Zimbabwe were tested for antibodies to anthrax PA antigen using the ELISA immunoassay. A random selection of 27 lion sera samples comprising 17 seropositive and 10 seronegative sera was further tested in the species-independent toxin neutralization assay (TNA) in order to validate the former as a surveillance tool for anthrax in African lions. Using the ELISA-PA immunoassay, 21.9% (25/114) of the lions tested positive for antibodies to anthrax. Seropositivity was recorded in all study areas, and there was no significant difference (p = .852) in seropositivity between lions in high- and low-risk anthrax zones. Also, there was no significant difference (McNemar's chi-square test = 0.9, p = .343) in the proportion of lions testing positive to anti-PA anthrax antibodies on ELISA-PA immunoassay compared with the TNA, with fair agreement between the two tests [kappa (K) statistic = 0.30; 0.08 < K<0.613]. Results of this study indicate that anthrax could be more widespread than 42 currently realized in Zimbabwe, and present in recognized high- and low-risk zones, including 43 where it has not been reported in over 20 years such as Hwange National Park. This is also the 44 first report documenting the presence of anthrax lethal toxin-neutralizing antibodies in naturally 45 infected carnivores, further confirming exposure to B. anthracis. The research results point to a 46 need for revisiting the currently recognized anthrax risk zones in Zimbabwe. This should be based 47 on improved surveillance of the disease in both wild and domestic animals for better understanding and control of the disease.


Assuntos
Antraz/veterinária , Anticorpos Antibacterianos/sangue , Bacillus anthracis/isolamento & purificação , Leões , Animais , Animais Selvagens , Animais de Zoológico , Antraz/epidemiologia , Antraz/imunologia , Anticorpos Neutralizantes/sangue , Ensaio de Imunoadsorção Enzimática/veterinária , Prevalência , Estudos Soroepidemiológicos , Zimbábue/epidemiologia
17.
Ecol Evol ; 10(7): 3276-3292, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32273986

RESUMO

Apex carnivores are wide-ranging, low-density, hard to detect, and declining throughout most of their range, making population monitoring both critical and challenging. Rapid and inexpensive index calibration survey (ICS) methods have been developed to monitor large African carnivores. ICS methods assume constant detection probability and a predictable relationship between the index and the actual population of interest. The precision and utility of the resulting estimates from ICS methods have been questioned. We assessed the performance of one ICS method for large carnivores-track counts-with data from two long-term studies of African lion populations. We conducted Monte Carlo simulation of intersections between transects (road segments) and lion movement paths (from GPS collar data) at varying survey intensities. Then, using the track count method we estimated population size and its confidence limits. We found that estimates either overstate precision or are too imprecise to be meaningful. Overstated precision stemmed from discarding the variance from population estimates when developing the method and from treating the conversion from tracks counts to population density as a back-transformation, rather than applying the equation for the variance of a linear function. To effectively assess the status of species, the IUCN has set guidelines, and these should be integrated in survey designs. We propose reporting the half relative confidence interval width (HRCIW) as an easily calculable and interpretable measure of precision. We show that track counts do not adhere to IUCN criteria, and we argue that ICS methods for wide-ranging low-density species are unlikely to meet those criteria. Established, intensive methods lead to precise estimates, but some new approaches, like short, intensive, (spatial) capture-mark-recapture (CMR/SECR) studies, aided by camera trapping and/or genetic identification of individuals, hold promise. A handbook of best practices in monitoring populations of apex carnivores is strongly recommended.

18.
Ecol Evol ; 9(16): 9111-9119, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31463008

RESUMO

The relationship between the spatiotemporal distribution of resources and patterns of sociality is widely discussed. While the resource dispersion hypothesis (RDH) was formulated to explain why animals sometimes live in groups from which they derive no obvious benefits, it has also been successfully applied to species that benefit from group living. Some empirical tests have supported the RDH, but others have not, so conclusions remain equivocal and further research is required to determine the extent to which RDH predictions hold in natural systems. Here, we test four predictions of the RDH in an African lion population in the context of their fission-fusion society. We analyzed data on group composition of GPS-collared lions and patterns of prey availability. Our results supported the first and second predictions of the RDH: Home range size (a) was independent of group size and (b) increased with distance between encounters with prey herds. Nonetheless, the third and fourth RDH predictions were not supported: (c) The measure of resource heterogeneity and (d) resource patch richness measured through prey herd size and body size had no significant effect on lion group size. However, regarding the fourth prediction, we added an adaptation to account for dynamics of fission-fusion society and found that the frequency of pride fission increased as group size increased. Our data set restricted us from going on to explore the effect of fission-fusion dynamics on the relationship between group size and patch richness. However, this should be investigated in future studies as including fission-fusion dynamics provides a more nuanced, realistic appreciation of lion society. Our study emphasizes the importance of understanding the complexity of a species' behavioral ecology within the framework of resource dispersion. Whatever larger theoretical framework may emerge to explain lion society, incorporating fission-fusion dynamics should allow the RDH to be refined and improved.

19.
Animals (Basel) ; 9(2)2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30744079

RESUMO

Conservation and natural resource management are increasingly attending the ethical elements of public decisions. Ethical considerations are challenging, in part, because they typically require accounting for the moral consideration of various human and nonhuman forms of life, whose interests sometimes conflict (or seem to conflict). A valuable tool for such evaluations is the formal analysis of ethical arguments. An ethical argument is a collection of premises, logically interrelated, to yield a conclusion that can be expressed in the form, "We ought to…" According to the rules of logic, a conclusion is supported by an argument if all its premises are true or appropriate and when it contains no mistaken inferences. We showed how the formal analysis of ethical arguments can be used to engage stakeholders and decision-makers in decision-making processes. We summarised the method with ten specific guidelines that would be applicable to any case. We illustrated the technique using a case study focused on captive-bred lions, the skeletons of which form part of an international trade to supply traditional medicine markets in Southeast Asia with felid bones. As a matter of public policy, the practice is a complicated nexus of concerns for entrepreneurial freedom, wildlife conservation, and the fair treatment of animals.

20.
Animals (Basel) ; 9(12)2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31835670

RESUMO

Human activity affecting the welfare of wild vertebrates, widely accepted to be sentient, and therefore deserving of moral concern, is widespread. A variety of motives lead to the killing of individual wild animals. These include to provide food, to protect stock and other human interests, and also for sport. The acceptability of such killing is widely believed to vary with the motive and method. Individual vertebrates are also killed by conservationists. Whether securing conservation goals is an adequate reason for such killing has recently been challenged. Conventional conservation practice has tended to prioritise ecological collectives, such as populations and species, when their interests conflict with those of individuals. Supporters of the 'Compassionate Conservation' movement argue both that conservationists have neglected animal welfare when such conflicts arise and that no killing for conservation is justified. We counter that conservationists increasingly seek to adhere to high standards of welfare, and that the extreme position advocated by some supporters of 'Compassionate Conservation', rooted in virtue ethics, would, if widely accepted, lead to considerable negative effects for conservation. Conservation practice cannot afford to neglect consequences. Moreover, the do-no-harm maxim does not always lead to better outcomes for animal welfare.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA