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1.
Glob Chang Biol ; 30(6): e17344, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38837566

RESUMO

Hosting 1460 plant and 126 vertebrate endemic species, the Great Escarpment (hereafter, Escarpment) forms a semi-circular "amphitheater" of mountains girdling southern Africa from arid west to temperate east. Since arid and temperate biota are usually studied separately, earlier studies overlooked the biogeographical importance of the Escarpment as a whole. Bats disperse more widely than other mammalian taxa, with related species and intraspecific lineages occupying both arid and temperate highlands of the Escarpment, providing an excellent model to address this knowledge gap. We investigated patterns of speciation and micro-endemism from modeled past, present, and future distributions in six clades of southern African bats from three families (Rhinolophidae, Cistugidae, and Vespertilionidae) having different crown ages (Pleistocene to Miocene) and biome affiliations (temperate to arid). We estimated mtDNA relaxed clock dates of key divergence events across the six clades in relation both to biogeographical features and patterns of phenotypic variation in crania, bacula and echolocation calls. In horseshoe bats (Rhinolophidae), both the western and eastern "arms" of the Escarpment have facilitated dispersals from the Afrotropics into southern Africa. Pleistocene and pre-Pleistocene "species pumps" and temperate refugia explained observed patterns of speciation, intraspecific divergence and, in two cases, mtDNA introgression. The Maloti-Drakensberg is a center of micro-endemism for bats, housing three newly described or undescribed species. Vicariance across biogeographic barriers gave rise to 29 micro-endemic species and intraspecific lineages whose distributions were congruent with those identified in other phytogeographic and zoogeographic studies. Although Köppen-Geiger climate models predict a widespread replacement of current temperate ecosystems in southern Africa by tropical or arid ecosystems by 2070-2100, future climate Maxent models for 13 bat species (all but one of those analyzed above) showed minimal range changes in temperate species from the eastern Escarpment by 2070, possibly due to the buffering effect of mountains to climate change.


Assuntos
Quirópteros , Mudança Climática , DNA Mitocondrial , Animais , Quirópteros/fisiologia , Quirópteros/genética , África Austral , DNA Mitocondrial/genética , DNA Mitocondrial/análise , Filogenia , Especiação Genética , Filogeografia , Distribuição Animal
2.
Biol Lett ; 19(10): 20230202, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37817576

RESUMO

Animals are faced with a variety of dangers or threats, which are increasing in frequency with ongoing environmental change. While our understanding of fearfulness of such dangers is growing in the context of predation and parasitism risk, the extent to which non-trophic, interspecific dangers elicit fear in animals remains less appreciated. We provide an experimental test for fear responses of savannah ungulates to a dominant and aggressive megaherbivore, the African bush elephant (Loxodonta africana), and contrast responses to an apex predator known to elicit fear in this system. Using an automated behavioural response system, we contrast vigilance and run responses of ungulates to elephant, leopard (Panthera pardus), and control (red-chested cuckoo Cuculus solitarius) vocalizations. Overall, we find that ungulates responded to elephant calls, both in terms of an increase in run and vigilance responses relative to controls. The magnitude of most behavioural responses (four of six considered) to elephant vocalizations were not significantly different than responses to leopards. These results suggest that megaherbivores can elicit strong non-trophic fear responses by ungulates and call to broaden frameworks on fear to consider dominant species, such as megaherbivores, as key modifiers of fear-induced interactions.


Assuntos
Elefantes , Animais , Elefantes/fisiologia , Mamíferos , Comportamento Predatório , Medo , Agressão , Aves
3.
Conserv Biol ; 37(6): e14146, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37424360

RESUMO

To evaluate conservation interventions, it is necessary to obtain reliable population trends for short (<10 years) time scales. Telemetry can be used to estimate short-term survival rates and is a common tool for assessing population trends, but it has limitations and can be biased toward specific behavioral traits of tagged individuals. Encounter rates calculated from transects can be useful for assessing changes across multiple species, but they can have large confidence intervals and be affected by variations in survey conditions. The decline of African vultures has been well-documented, but understanding of recent trends is lacking. To examine population trends, we used survival estimates from telemetry data collected over 6 years (primarily for white-backed vultures [Gyps africanus]) and transect counts conducted over 8 years (for 7 scavenging raptors) in 3 large protected areas in Tanzania. Population trends were estimated using survival analysis combined with the Leslie Lefkovitch matrix model from the telemetry data and using Bayesian mixed effects generalized linear regression models from the transect data. Both methods showed significant declines for white-backed vultures in Ruaha and Nyerere National Parks. Only telemetry estimates suggested significant declines in Katavi National Park. Encounter rates calculated from transects also showed declines in Nyerere National Park for lappet-faced vultures (38% annual declines) and Bateleurs (18%) and in Ruaha National Park for white-headed vultures (Trigonoceps occipitalis) (19%). Mortality rates recorded and inferred from telemetry suggested that poisoning is prevalent. However, only 6 mortalities of the 26 presumed mortalities were confirmed to be caused by poisoning, highlighting the challenges of determining the cause of death when working across large landscapes. Despite declines, our data provide evidence that southern Tanzania has higher current encounter rates of African vultures than elsewhere in East Africa. Preventing further declines will depend greatly on mitigating poisoning. Based on our results, we suggest that the use of multiple techniques improves understanding of population trends over the short term.


Importancia de combinar los conteos de transectos y los datos de telemetría para determinar las tendencias poblacionales a corto plazo de especies amenazadas a nivel mundial Resumen Para evaluar las intervenciones de conservación es necesario obtener tendencias poblacionales confiables para escalas temporales cortas (<10 años). La telemetría puede usarse para estimar las tasas de supervivencia a corto plazo, además de que es una herramienta común para analizar las tendencias poblacionales, pero tiene limitantes y puede sesgarse con el comportamiento específico de los individuos marcados. Las tasas de encuentro calculadas a partir de transectos pueden ser útiles para analizar cambios en varias especies, aunque pueden tener intervalos grandes de confianza y verse afectadas por las variantes en las condiciones del censo. La declinación de los buitres africanos está bien documentada, pero hace falta el conocimiento sobre las tendencias recientes. Usamos las estimaciones de supervivencia tomadas de datos telemétricos recolectados durante seis años (principalmente del buitre Gyps africanus) y los conteos de transecto de siete especies carroñeras realizados durante ocho años en tres áreas protegidas en Tanzania. Estimamos las tendencias poblacionales con la combinación de análisis de supervivencia y el modelo de matriz Leslie Lefkovitch hecho con los datos telemétricos y usando modelos bayesianos de regresión lineal generalizada de efectos mixtos hechos con los datos de los transectos. Ambos métodos indicaron declinaciones significativas de Gyps africanus en los Parques Nacionales Ruaha y Nyerere. Sólo las estimaciones telemétricas sugirieron una declinación significativa en el Parque Nacional Katavi. Las tasas de encuentro calculadas a partir de los transectos también indicaron declinaciones de Torgos tracheliotos (38% de declinaciones anuales) y de Terathopius ecaudutus (18%) en el Parque Nacional Nyerere y de Trigonoceps occipitalis (19%) en el Parque Nacional Ruaha. Las muertes registradas e inferidas a partir de la telemetría sugieren que el envenenamiento es prevalente. Sin embargo, sólo se confirmaron seis muertes por envenenamiento de las 26 supuestas, lo que resalta los obstáculos para determinar la causa de muerte cuando se trabaja en paisajes amplios. A pesar de las declinaciones, nuestros datos proporcionan evidencia de que el sur de Tanzania tiene tasas actuales de encuentro con buitres africanos más altas que en cualquier otra parte del occidente de África. La prevención de declinaciones en el futuro dependerá principalmente de evitar el envenenamiento. Con base en nuestros resultados, sugerimos que el uso de técnicas múltiples incrementa el conocimiento sobre las tendencias poblacionales a corto plazo.


Assuntos
Espécies em Perigo de Extinção , Falconiformes , Humanos , Animais , Teorema de Bayes , Conservação dos Recursos Naturais , Tanzânia
4.
Proc Natl Acad Sci U S A ; 117(36): 22274-22280, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32848069

RESUMO

Connectivity has long played a central role in ecological and evolutionary theory and is increasingly emphasized for conserving biodiversity. Nonetheless, connectivity assessments often focus on individual species even though understanding and preserving connectivity for entire communities is urgently needed. Here we derive and test a framework that harnesses the well-known allometric scaling of animal movement to predict community-level connectivity across protected area networks. We used a field translocation experiment involving 39 species of southern African birds to quantify movement capacity, scaled this relationship to realized dispersal distances determined from ring-and-recovery banding data, and used allometric scaling equations to quantify community-level connectivity based on multilayer network theory. The translocation experiment explained observed dispersal distances from ring-recovery data and emphasized allometric scaling of dispersal based on morphology. Our community-level networks predicted that larger-bodied species had a relatively high potential for connectivity, while small-bodied species had lower connectivity. These community networks explained substantial variation in observed bird diversity across protected areas. Our results highlight that harnessing allometric scaling can be an effective way of determining large-scale community connectivity. We argue that this trait-based framework founded on allometric scaling provides a means to predict connectivity for entire communities, which can foster empirical tests of community theory and contribute to biodiversity conservation strategies aimed at mitigating the effects of environmental change.


Assuntos
Distribuição Animal , Aves/fisiologia , Ecossistema , Modelos Biológicos , Animais
5.
Mol Ecol ; 29(24): 4970-4984, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33058329

RESUMO

It has long been of interest to identify the phenotypic traits that mediate reproductive isolation between related species, and more recently, the genes that underpin them. Much work has focused on identifying genes associated with animal colour, with the candidate gene CYP2J19 identified in laboratory studies as the ketolase converting yellow dietary carotenoids to red ketocarotenoids in birds with red pigments. However, evidence that CYP2J19 explains variation between red and yellow feather coloration in wild populations of birds is lacking. Hybrid zones provide the opportunity to identify genes associated with specific traits. Here we investigate genomic regions associated with colour in red-fronted and yellow-fronted tinkerbirds across a hybrid zone in southern Africa. We sampled 85 individuals, measuring spectral reflectance of forecrown feathers and scoring colours from photographs, while testing for carotenoid presence with Raman spectroscopy. We performed a genome-wide association study to identify associations with carotenoid-based coloration, using double-digest RAD sequencing aligned to a short-read whole genome of a Pogoniulus tinkerbird. Admixture mapping using 104,933 single nucleotide polymorphisms (SNPs) identified a region of chromosome 8 that includes CYP2J19 as the only locus with more than two SNPs significantly associated with both crown hue and crown score, while Raman spectra provided evidence of ketocarotenoids in red feathers. Asymmetric backcrossing in the hybrid zone suggests that yellow-fronted females mate more often with red-fronted males than vice versa. Female red-fronted tinkerbirds mating assortatively with red-crowned males is consistent with the hypothesis that converted carotenoids are an honest signal of quality.


Assuntos
Carotenoides , Estudo de Associação Genômica Ampla , África Austral , Animais , Aves/genética , Cor , Feminino , Masculino , Pigmentação/genética
6.
Proc Biol Sci ; 281(1793)2014 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-25209935

RESUMO

Vultures are recognized as the scroungers of the natural world, owing to their ecological role as obligate scavengers. While it is well known that vultures use intraspecific social information as they forage, the possibility of inter-guild social information transfer and the resulting multi-species social dilemmas has not been explored. Here, we use data on arrival times at carcasses to show that such social information transfer occurs, with raptors acting as producers of information and vultures acting as scroungers of information. We develop a game-theoretic model to show that competitive asymmetry, whereby vultures dominate raptors at carcasses, predicts this evolutionary outcome. We support this theoretical prediction using empirical data from competitive interactions at carcasses. Finally, we use an individual-based model to show that these producer-scrounger dynamics lead to vultures being vulnerable to declines in raptor populations. Our results show that social information transfer can lead to important non-trophic interactions among species and highlight important potential links among social evolution, community ecology and conservation biology. With vulture populations suffering global declines, our study underscores the importance of ecosystem-based management for these endangered keystone species.


Assuntos
Conservação dos Recursos Naturais , Águias/fisiologia , Falconiformes/fisiologia , Comportamento Alimentar , Animais , Teoria dos Jogos , Quênia , Modelos Biológicos
7.
Ecol Evol ; 14(7): e11486, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39005885

RESUMO

Gut bacterial communities provide flexibility to hosts during dietary changes. Despite the increasing number of studies exploring the associations between broader dietary guilds of mammalian hosts and their gut bacteria, it is generally unclear how diversity and variability in consumed diets link to gut bacterial taxa in wild non-primate mammals, particularly in omnivores. Here, we contribute to filling this gap by exploring consumed diets and gut bacterial community compositions with metabarcoding of faecal samples for two African mammals, Civettictis civetta and Genetta spp., from the family Viverridae. For each individual sample, we characterised bacterial communities and identified dietary taxa by sequencing vertebrate, invertebrate and plant markers. This led us to establish diet compositions that diverged from what has previously been found from visual identification methods. Specifically, while the two genera have been categorised into the same dietary guild, we detected more animal dietary items than plant items in C. civetta, while in Genetta spp., we observed the opposite. We further found that individuals with similar diets have similar gut bacterial communities within both genera. This association tended to be driven by specific links between dietary items and gut bacterial genera, rather than communities as a whole, implying diet-driven selection for specific gut microbes in individual wild hosts. Our findings underline the importance of molecular tools for improving characterisations of omnivorous mammalian diets and highlight the opportunities for simultaneously disentangling links between diets and gut symbionts. Such insights can inform robustness and flexibility in host-microbe symbioses to dietary change associated with seasonal and habitat changes.

8.
Nat Commun ; 15(1): 3095, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653976

RESUMO

Vocal rhythm plays a fundamental role in sexual selection and species recognition in birds, but little is known of its genetic basis due to the confounding effect of vocal learning in model systems. Uncovering its genetic basis could facilitate identifying genes potentially important in speciation. Here we investigate the genomic underpinnings of rhythm in vocal non-learning Pogoniulus tinkerbirds using 135 individual whole genomes distributed across a southern African hybrid zone. We find rhythm speed is associated with two genes that are also known to affect human speech, Neurexin-1 and Coenzyme Q8A. Models leveraging ancestry reveal these candidate loci also impact rhythmic stability, a trait linked with motor performance which is an indicator of quality. Character displacement in rhythmic stability suggests possible reinforcement against hybridization, supported by evidence of asymmetric assortative mating in the species producing faster, more stable rhythms. Because rhythm is omnipresent in animal communication, candidate genes identified here may shape vocal rhythm across birds and other vertebrates.


Assuntos
Vocalização Animal , Animais , Vocalização Animal/fisiologia , Masculino , Genômica , Genoma/genética , Feminino , Aves Canoras/genética , Aves Canoras/fisiologia , Aves/genética , Aves/fisiologia
9.
Sci Rep ; 14(1): 5971, 2024 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-38472297

RESUMO

Recent biological surveys of ancient inselbergs in southern Malawi and northern Mozambique have led to the discovery and description of many species new to science, and overlapping centres of endemism across multiple taxa. Combining these endemic taxa with data on geology and climate, we propose the 'South East Africa Montane Archipelago' (SEAMA) as a distinct ecoregion of global biological importance. The ecoregion encompasses 30 granitic inselbergs reaching > 1000 m above sea level, hosting the largest (Mt Mabu) and smallest (Mt Lico) mid-elevation rainforests in southern Africa, as well as biologically unique montane grasslands. Endemic taxa include 127 plants, 45 vertebrates (amphibians, reptiles, birds, mammals) and 45 invertebrate species (butterflies, freshwater crabs), and two endemic genera of plants and reptiles. Existing dated phylogenies of endemic animal lineages suggests this endemism arose from divergence events coinciding with repeated isolation of these mountains from the pan-African forests, together with the mountains' great age and relative climatic stability. Since 2000, the SEAMA has lost 18% of its primary humid forest cover (up to 43% in some sites)-one of the highest deforestation rates in Africa. Urgently rectifying this situation, while addressing the resource needs of local communities, is a global priority for biodiversity conservation.


Assuntos
Borboletas , Animais , Biodiversidade , África Oriental , Répteis , Florestas , África do Sul , Filogenia , Mamíferos
10.
Sci Data ; 11(1): 191, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38346970

RESUMO

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species' population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate 'intactness scores': the remaining proportion of an 'intact' reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region's major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Animais , Biodiversidade , Mamíferos , Vertebrados , Plantas , África
11.
Zootaxa ; 3746: 123-42, 2013 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-25113471

RESUMO

Resolving species limits within the genus Miniopterus has traditionally been complicated by the presence of cryptic species with overlapping morphological features. We use molecular techniques, cranio-dental characters and tragus shape to describe a new species of Miniopterus from Mozambique, M. mossambicus. Miniopterus mossambicus shows > 12% divergence in cytochrome-b sequence from its nearest congeners (the Malagasy M. gleni and M. griveaudi) and > 15% divergence from the morphologically similar M. natalensis, M. fraterculus and M. minor (all of which occur in southern and eastern Africa). There is considerable overlap in cranio-dental characters of the southern African species, particularly M. natalensis and M. mossambicus. However, tragus shape and multivariate comparisons of skull measurements can be used to separate these species. Based on morphological comparisons of museum specimens, this species may also be present in neighbouring Malawi and Zimbabwe, suggesting that it is probably distributed widely in south-central Africa. 


Assuntos
Quirópteros/classificação , Animais , Quirópteros/anatomia & histologia , Quirópteros/genética , Citocromos b , Masculino , Dados de Sequência Molecular , Moçambique , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
12.
Pathogens ; 12(7)2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37513706

RESUMO

Madagascar is home to an extraordinary diversity of endemic mammals hosting several zoonotic pathogens. Although the African origin of Malagasy mammals has been addressed for a number of volant and terrestrial taxa, the origin of their hosted zoonotic pathogens is currently unknown. Using bats and Leptospira infections as a model system, we tested whether Malagasy mammal hosts acquired these infections on the island following colonization events, or alternatively brought these bacteria from continental Africa. We first described the genetic diversity of pathogenic Leptospira infecting bats from Mozambique and then tested through analyses of molecular variance (AMOVA) whether the genetic diversity of Leptospira hosted by bats from Mozambique, Madagascar and Comoros is structured by geography or by their host phylogeny. This study reveals a wide diversity of Leptospira lineages shed by bats from Mozambique. AMOVA strongly supports that the diversity of Leptospira sequences obtained from bats sampled in Mozambique, Madagascar, and Comoros is structured according to bat phylogeny. Presented data show that a number of Leptospira lineages detected in bat congeners from continental Africa and Madagascar are imbedded within monophyletic clades, strongly suggesting that bat colonists have indeed originally crossed the Mozambique Channel while infected with pathogenic Leptospira.

13.
PLoS Negl Trop Dis ; 17(11): e0011732, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37948462

RESUMO

BACKGROUND: Halving snakebite morbidity and mortality by 2030 requires countries to develop both prevention and treatment strategies. The paucity of data on the global incidence and severity of snakebite envenoming causes challenges in prioritizing and mobilising resources for snakebite prevention and treatment. In line with the World Health Organisation's 2019 Snakebite Strategy, this study sought to investigate Eswatini's snakebite epidemiology and outcomes, and identify the socio-geographical factors associated with snakebite risk. METHODOLOGY: Programmatic data from the Ministry of Health, Government of Eswatini 2019-2021, was used to assess the epidemiology and outcomes of snakebite in Eswatini. We developed a snake species richness map from the occurrence data of all venomous snakes of medical importance in Eswatini that was subjected to niche modelling. We formulated four risk indices using snake species richness, various geospatial datasets and reported snakebites. A multivariate cluster modelling approach using these indices was developed to estimate risk of snakebite and the outcomes of snakebite in Eswatini. PRINCIPAL FINDINGS: An average of 466 snakebites was recorded annually in Eswatini. Bites were recorded across the entire country and peaked in the evening during summer months. Two cluster risk maps indicated areas of the country with a high probability of snakebite and a high probability of poor snakebite outcomes. The areas with the highest rate of snakebite risk were primarily in the rural and agricultural regions of the country. SIGNIFICANCE: These models can be used to inform better snakebite prevention and treatment measures to enable Eswatini to meet the global goal of reducing snakebite morbidity and mortality by 50% by 2030. The supply chain challenges of antivenom affecting southern Africa and the high rates of snakebite identified in our study highlight the need for improved snakebite prevention and treatment tools that can be employed by health care workers stationed at rural, community clinics.


Assuntos
Mordeduras de Serpentes , Animais , Humanos , Mordeduras de Serpentes/terapia , Essuatíni , Serpentes , Antivenenos/uso terapêutico , Saúde Global
14.
Heliyon ; 7(3): e06563, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33851055

RESUMO

Agricultural intensification is a threat to terrestrial ecosystems around the world. Agricultural areas, especially monocultures, create homogenous landscapes for wildlife. However, certain crops, such as sugarcane, are harvested in phases, creating a mosaic of fields in different stages of growth. We investigated changes in avian communities across four different sugarcane growth stages: emerging, short, medium and tall sugarcane, as well as control sites that represented native savanna habitat in northeast Eswatini prior to conversion to agriculture. In total, we sampled nine sites in sugarcane fields (at different growth stages) and three in native savanna. We conducted bird counts at 5-week intervals along 200m line transects over both the breeding and non-breeding seasons. We recorded a total of 124 bird species belonging to 58 families. Bird species richness and diversity were higher in savannas compared to any stages of growth in sugarcane. In contrast, functional beta diversity and uniqueness were higher in sugarcane than in savanna. Community composition was also different between the two land-uses. While there was overlap in bird species composition between different sugarcane growth stages, there was high beta diversity and high turnover between sites, indicative of the high temporal and spatial variability in bird communities in sugarcane fields. We demonstrated that the spatial and temporal variability created by the different growth stages of sugarcane promotes the occurrence of species with different traits, which may contribute to ecosystem functioning and promote the conservation of bird species as sugarcane fields can provide resource complementation for species with different needs.

15.
Ecohealth ; 18(4): 421-428, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34970712

RESUMO

We investigated the prevalence of coronaviruses in 44 bats from four families in northeastern Eswatini using high-throughput sequencing of fecal samples. We found evidence of coronaviruses in 18% of the bats. We recovered full or near-full-length genomes from two bat species: Chaerephon pumilus and Afronycteris nana, as well as additional coronavirus genome fragments from C. pumilus, Epomophorus wahlbergi, Mops condylurus, and Scotophilus dinganii. All bats from which we detected coronaviruses were captured leaving buildings or near human settlements, demonstrating the importance of continued surveillance of coronaviruses in bats to better understand the prevalence, diversity, and potential risks for spillover.


Assuntos
Quirópteros , Infecções por Coronavirus , Coronavirus , Metagenômica , Animais , Quirópteros/virologia , Coronavirus/genética , Infecções por Coronavirus/veterinária , Essuatíni , Variação Genética , Genoma Viral , Filogenia
16.
Int J Parasitol Parasites Wildl ; 13: 62-71, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32884900

RESUMO

Infectious diseases vary in prevalence and pathology among host species. Species may differ in prevalence of infection due to varying exposure and susceptibility to disease agents throughout their lifetime, which may be attributable to underlying differences in their phenology, physiology and behavior. A recently growing body of literature has focused on the utility of host life-history traits to provide mechanistic explanations for interspecific variation in host-parasite associations. In this study, we utilized diverse avian and haemosporidian assemblages in an African savanna to evaluate the link between haemosporidia prevalence (Plasmodium, Haemoproteus, Leucocytozoon) and avian life-history traits such as body size, mating system, nest care and nest structure. We found that variation of haemosporidia prevalence was consistent with life-history traits that pertain to the reproduction of avian host. Nest care was the single most important predictor of infection status. In birds with shared and female-only nest care, the expected rates of parasitism were between 8- and 12-fold higher than in avian brood parasites that provide no nest care. This finding supports the hypothesis that parental care is an evolutionarily costly life-history trait that increases species' risk of infection with vector-borne diseases. The influence of other host traits (nest structure, body size) was less consistent suggesting that differences in the vectors' ecology and host-seeking behavior produce variable patterns of parasitism among haemosporidia genera. Nest structure influenced infection with Haemoproteus and Leucocytozoon only. Leucocytozoon infections were associated with ground-nesting birds, while Haemoproteus infections were associated with birds that build open nest structures. Body size was an important predictor of Leucocytozoon infections, particularly large-bodied birds like guineafowl and doves, which exhibited high prevalences.

17.
Epidemics ; 29: 100366, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31744768

RESUMO

Ebola virus disease (EVD) presents a threat to public health throughout equatorial Africa. Despite numerous 'spillover' events into humans and apes, the maintenance reservoirs and mechanism of spillover are poorly understood. Evidence suggests fruit bats play a role in both instances, yet data remain sparse and bats exhibit a wide range of life history traits. Here we pool sparse data and use a mechanistic approach to examine how birthing cycles of African fruit bats, molossid bats, and non-molossid microbats inform the spatio-temporal occurrence of EVD spillover. We create ensemble niche models to predict spatio-temporally varying bat birthing and model outbreaks as spatio-temporal Poisson point processes. We predict three distinct annual birthing patterns among African bats along a latitudinal gradient. Of the EVD spillover models tested, the best by quasi-Akaike information criterion (qAIC) and by out of sample prediction included significant African bat birth-related terms. Temporal bat birthing terms fit in the best models for both human and animal outbreaks were consistent with hypothesized viral dynamics in bat populations, but purely spatial models also performed well. Our best model predicted risk of EVD spillover at locations of the two 2018 EVD outbreaks in the Democratic Republic of the Congo was within the top 12-35% and 0.1% of all 25 × 25 km spatial cells analyzed in sub-Saharan Africa. Results suggest that sparse data can be leveraged to help understand complex systems.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/transmissão , Animais , Quirópteros , República Democrática do Congo/epidemiologia , Surtos de Doenças , Reservatórios de Doenças , Humanos
18.
Sci Rep ; 9(1): 16857, 2019 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-31727923

RESUMO

Altered disturbance regimes, increasing atmospheric CO2, and other processes have increased woody cover and homogenized vegetation in savannas across the planet. African savannas with extensive versus minimal woody cover often have vastly different animal communities. However, we lack a clear mechanistic understanding of why animal communities are changing with vegetation structure. Our goal for this study was to understand how vegetation structure in an African savanna shaped the perceived predation risk of small mammals, hence affecting their activity. Using a reciprocal measure of standard giving-up-densities, amount of food eaten, we found sharp declines in rodents' perceived predation risk and increased rodent activity underneath shrub cover. This response was consistent across species; however, species showed subtle differences in their responses to grassy vegetation. Our findings suggest that areas of minimal or extensive shrub cover (shrub encroachment) may be homogenizing rodents' perceptions of predation risk and thus shaping their use of space.


Assuntos
Poaceae/fisiologia , Comportamento Predatório/fisiologia , Roedores/fisiologia , Animais , Essuatíni , Cadeia Alimentar , Pradaria , Dinâmica Populacional , Roedores/psicologia , Árvores/fisiologia
19.
Zool Res ; 40(1): 3-52, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30348934

RESUMO

Kenya has a rich mammalian fauna. We reviewed recently published books and papers including the six volumes of Mammals of Africa to develop an up-to-date annotated checklist of all mammals recorded from Kenya. A total of 390 species have been identified in the country, including 106 species of rodents, 104 species of bats, 63 species of even-toed ungulates (including whales and dolphins), 36 species of insectivores and carnivores, 19 species of primates, five species of elephant shrews, four species of hyraxes and odd-toed ungulates, three species of afrosoricids, pangolins, and hares, and one species of aardvark, elephant, sirenian and hedgehog. The number of species in this checklist is expected to increase with additional surveys and as the taxonomic status of small mammals (e.g., bats, shrews and rodents) becomes better understood.


Assuntos
Distribuição Animal , Biodiversidade , Mamíferos , Animais , Quênia
20.
R Soc Open Sci ; 5(12): 180849, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30662720

RESUMO

Bats play important ecological roles in tropical systems, yet how these communities are structured is still poorly understood. Our study explores the structure of African bat communities using morphological characters to define the morphospace occupied by these bats and stable isotope analysis to define their dietary niche breadth. We compared two communities, one in rainforest (Liberia) and one in savannah (South Africa), and asked whether the greater richness in the rainforest was due to more species 'packing' into the same morphospace and trophic space than bats from the savannah, or some other arrangement. In the rainforest, bats occupied a larger area in morphospace and species packing was higher than in the savannah; although this difference disappeared when comparing insectivorous bats only. There were also differences in morphospace occupied by different foraging groups (aerial, edge, clutter and fruitbat). Stable isotope analysis revealed that the range of δ 13C values was almost double in rainforest than in savannah indicating a greater range of utilization of basal C3 and C4 resources in the former site, covering primary productivity from both these sources. The ranges in δ 15N, however, were similar between the two habitats suggesting a similar number of trophic levels. Niche breadth, as defined by either standard ellipse area or convex hull, was greater for the bat community in rainforest than in savannah, with all four foraging groups having larger niche breadths in the former than the latter. The higher inter-species morphospace and niche breadth in forest bats suggest that species packing is not necessarily competitive. By employing morphometrics and stable isotope analysis, we have shown that the rainforest bat community packs more species in morphospace and uses a larger niche breadth than the one in savannah.

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