ORCID Profile
0000-0002-2553-7598
Current Organisation
Griffith University
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Population Ecology | Wildlife and Habitat Management | Environmental Science and Management | Conservation and Biodiversity
Expanding Knowledge in the Environmental Sciences | Control of Pests, Diseases and Exotic Species in Fresh, Ground and Surface Water Environments | Fresh, Ground and Surface Water Flora, Fauna and Biodiversity |
Publisher: Public Library of Science (PLoS)
Date: 22-02-2013
Publisher: Wiley
Date: 24-08-2017
DOI: 10.1111/MEC.14291
Abstract: Social interactions are rarely random. In some instances, animals exhibit homophily or heterophily, the tendency to interact with similar or dissimilar conspecifics, respectively. Genetic homophily and heterophily influence the evolutionary dynamics of populations, because they potentially affect sexual and social selection. Here, we investigate the link between social interactions and allele frequencies in foraging flocks of great tits (Parus major) over three consecutive years. We constructed co-occurrence networks which explicitly described the splitting and merging of 85,602 flocks through time (fission-fusion dynamics), at 60 feeding sites. Of the 1,711 birds in those flocks, we genotyped 962 in iduals at 4,701 autosomal single nucleotide polymorphisms (SNPs). By combining genomewide genotyping with repeated field observations of the same in iduals, we were able to investigate links between social structure and allele frequencies at a much finer scale than was previously possible. We explicitly accounted for potential spatial effects underlying genetic structure at the population level. We modelled social structure and spatial configuration of great tit fission-fusion dynamics with eigenvector maps. Variance partitioning revealed that allele frequencies were strongly affected by group fidelity (explaining 27%-45% of variance) as in iduals tended to maintain associations with the same conspecifics. These conspecifics were genetically more dissimilar than expected, shown by genomewide heterophily for pure social (i.e., space-independent) grouping preferences. Genomewide homophily was linked to spatial configuration, indicating spatial segregation of genotypes. We did not find evidence for homophily or heterophily for putative socially relevant candidate genes or any other SNP markers. Together, these results demonstrate the importance of distinguishing social and spatial processes in determining population structure.
Publisher: Wiley
Date: 27-06-2014
DOI: 10.1111/COBI.12322
Abstract: Wildlife diseases pose an increasing threat to bio ersity and are a major management challenge. A striking ex le of this threat is the emergence of chytridiomycosis. Despite diagnosis of chytridiomycosis as an important driver of global hibian declines 15 years ago, researchers have yet to devise effective large-scale management responses other than biosecurity measures to mitigate disease spread and the establishment of disease-free captive assurance colonies prior to or during disease outbreaks. We examined the development of management actions that can be implemented after an epidemic in surviving populations. We developed a conceptual framework with clear interventions to guide experimental management and applied research so that further extinctions of hibian species threatened by chytridiomycosis might be prevented. Within our framework, there are 2 management approaches: reducing Batrachochytrium dendrobatidis (the fungus that causes chytridiomycosis) in the environment or on hibians and increasing the capacity of populations to persist despite increased mortality from disease. The latter approach emphasizes that mitigation does not necessarily need to focus on reducing disease-associated mortality. We propose promising management actions that can be implemented and tested based on current knowledge and that include habitat manipulation, antifungal treatments, animal translocation, bioaugmentation, head starting, and selection for resistance. Case studies where these strategies are being implemented will demonstrate their potential to save critically endangered species.
Publisher: Wiley
Date: 18-03-2010
DOI: 10.1111/J.1558-5646.2010.00991.X
Abstract: Phenotypic plasticity is an important mechanism via which populations can respond to changing environmental conditions, but we know very little about how natural populations vary with respect to plasticity. Here we use random-regression animal models to understand the multivariate phenotypic and genetic patterns of plasticity variation in two key life-history traits, laying date and clutch size, using data from long-term studies of great tits in The Netherlands (Hoge Veluwe [HV]) and UK (Wytham Woods [WW]). We show that, while population-level responses of laying date and clutch size to temperature were similar in the two populations, between-in idual variation in plasticity differed markedly. Both populations showed significant variation in phenotypic plasticity (IxE) for laying date, but IxE was significantly higher in HV than in WW. There were no significant genotype-by-environment interactions (GxE) for laying date, yet differences in GxE were marginally nonsignificant between HV and WW. For clutch size, we only found significant IxE and GxE in WW but no significant difference between populations. From a multivariate perspective, plasticity in laying date was not correlated with plasticity in clutch size in either population. Our results suggest that generalizations about the form and cause of any response to changing environmental conditions across populations may be difficult.
Publisher: Cold Spring Harbor Laboratory
Date: 05-11-2016
DOI: 10.1101/085944
Abstract: Social structure can have profound evolutionary and ecological implications for animal populations. Structure can arise and be maintained via social preferences or be indirectly shaped by habitat structure. Understanding how social structure emerges is important for understanding the potential links between social structure and evolutionary and ecological processes. Here, we study a large community of wild birds fitted with uniquely-coded passive integrated transponder (PIT) tags and recorded on a grid of automated feeders fitted with radio frequency identification (RFID) antennae. We show that both large-scale and fine-scale network communities are consistent across years in this population, despite high generational turn-over. Studying the process that generates community structure, here the movement of in idual birds across the woodland, suggests an important role of habitat geometry in shaping population-level social community structure. Our study highlights how relatively simple factors can produce apparent emergent social structure at the population scale, which has widespread implications for understanding eco-evolutionary dynamics.
Publisher: Oxford University Press (OUP)
Date: 08-1997
DOI: 10.1093/OXFORDJOURNALS.MOLBEV.A025826
Abstract: The application of microsatellites in evolutionary studies requires an understanding of the patterns governing their evolution in different species. The finding that homologous microsatellite loci are longer, i.e., containing more repeat units, in human and in other primates has been taken as evidence for directional microsatellite evolution and for a difference in the rate of evolution between species. However, it has been argued that this finding is an inevitable consequence of biased selection of longer-than-average microsatellites in human, because cloning procedures are adopted to generate polymorphic and, hence, long markers. As a test of this hypothesis, we conducted a reciprocal comparison of the lengths of microsatellite loci in cattle and sheep using markers derived from the bovine genome as well as the ovine genome. In both cases, lification products were longer in the focal species, and loci were also more polymorphic in the species from which they were originally cloned. The crossing pattern that we found suggests that interspecific length differences detected at homologous microsatellite loci are the result of biased selection of loci associated with cloning procedures. Hence, comparisons of microsatellite evolution between species are flawed unless they are based on reciprocal analyses or on genuinely random selection of loci with respect to repeat length.
Publisher: Wiley
Date: 11-2001
Publisher: Wiley
Date: 02-2018
DOI: 10.1111/MEC.14493
Abstract: Potentiating the evolution of immunity is a promising strategy for addressing bio ersity diseases. Assisted selection for infection resistance may enable the recovery and persistence of hibians threatened by chytridiomycosis, a devastating fungal skin disease threatening hundreds of species globally. However, knowledge of the mechanisms involved in the natural evolution of immunity to chytridiomycosis is limited. Understanding the mechanisms of such resistance may help speed-assisted selection. Using a transcriptomics approach, we examined gene expression responses of endangered alpine tree frogs (Litoria verreauxii alpina) to subclinical infection, comparing two long-exposed populations with a naïve population. We performed a blinded, randomized and controlled exposure experiment, collecting skin, liver and spleen tissues at 4, 8 and 14 days postexposure from 51 wild-caught captively reared infection-naïve adult frogs for transcriptome assembly and differential gene expression analyses. We analysed our results in conjunction with infection intensity data, and the results of a large clinical survival experiment run concurrently with in iduals from the same clutches. Here, we show that frogs from an evolutionarily long-exposed and phenotypically more resistant population of the highly susceptible alpine tree frog demonstrate a more robust innate and adaptive immune response at the critical early subclinical stage of infection when compared with two more susceptible populations. These results are consistent with the occurrence of evolution of resistance against chytridiomycosis, help to explain underlying resistance mechanisms, and provide genes of potential interest and sequence data for future research. We recommend further investigation of cell-mediated immunity pathways, the role of interferons and mechanisms of lymphocyte suppression.
Publisher: Springer Science and Business Media LLC
Date: 2005
DOI: 10.1038/NATURE03051
Abstract: Evolutionary theory predicts that local population ergence will depend on the balance between the ersifying effect of selection and the homogenizing effect of gene flow. However, spatial variation in the expression of genetic variation will also generate differential evolutionary responses. Furthermore, if dispersal is non-random it may actually reinforce, rather than counteract, evolutionary differentiation. Here we document the evolution of differences in body mass within a population of great tits, Parus major, inhabiting a single continuous woodland, over a 36-year period. We show that genetic variance for nestling body mass is spatially variable, that this generates different potential responses to selection, and that this ersifying effect is reinforced by non-random dispersal. Matching the patterns of variation, selection and evolution with population ecological data, we argue that the small-scale differentiation is driven by density-related differences in habitat quality affecting settlement decisions. Our data show that when gene flow is not homogeneous, evolutionary differentiation can be rapid and can occur over surprisingly small spatial scales. Our findings have important implications for questions of the scale of adaptation and speciation, and challenge the usual treatment of dispersal as a force opposing evolutionary differentiation.
Publisher: Wiley
Date: 29-02-2016
Abstract: Pathogens can be critical drivers of the abundance and distribution of wild animal populations. The presence of an overdispersed pathogen load distribution between hosts (where few hosts harbour heavy parasite burdens and light infections are common) can have an important stabilizing effect on host-pathogen dynamics where infection intensity determines pathogenicity. This may potentially lead to endemicity of an introduced pathogen rather than extirpation of the host and/or pathogen. Overdispersed pathogen load distributions have rarely been considered in wild animal populations as an important component of the infection dynamics of microparasites such as bacteria, viruses, protozoa and fungi. Here we examined the abundance, distribution and transmission of the model fungal pathogen Batrachochytrium dendrobatidis (Bd, cause of hibian chytridiomycosis) between wild-caught Litoria rheocola (common mist frogs) to investigate the effects of an overdispersed pathogen load distribution on the host population in the wild. We quantified host survival, infection incidence and recovery probabilities relative to infectious burden, and compared the results of models where pathogen overdispersion either was or was not considered an important feature of host-pathogen dynamics. We found the distribution of Bd load between hosts to be highly overdispersed. We found that host survival was related to infection burden and that accounting for pathogen overdispersion allowed us to better understand infection dynamics and their implications for disease control. In addition, we found that the pattern of host infections and recoveries varied markedly with season whereby (i) infections established more in winter, consistent with temperature-dependent effects on fungal growth, and (ii) recoveries (loss of infection) occurred frequently in the field throughout the year but were less likely in winter. Our results suggest that pathogen overdispersion is an important feature of endemic chytridiomycosis and that intensity of infection determines disease impact. These findings have important implications for our understanding of chytridiomycosis dynamics and the application of management strategies for disease mitigation. We recommend quantifying in idual infectious burdens rather than infection state where possible in microparasitic diseases.
Publisher: Wiley
Date: 07-2007
DOI: 10.1111/J.1558-5646.2007.00128.X
Abstract: Describing natural selection on phenotypic traits under varying environmental conditions is essential for a quantitative assessment of the scale at which adaptation might occur and of the impact of environmental variability on evolution. Here we analyzed patterns of multivariate selection via fecundity and viability on three reproductive traits (laying date, clutch size, and egg weight) in a population of great tits (Parus major). We quantified selection under different environmental conditions using (1) local variation in breeding density and (2) distinct areas of the population's habitat. We found that selection gradients were generally stronger for fecundity than for viability selection. We also found correlational selection acting on the combination of laying date and clutch size this is the first documented evidence of such selection acting on these two traits in a passerine bird. Our analyses showed that both local breeding density and habitat significantly influenced selection patterns, hence favoring different patterns of reproductive investment at a small-scale relative to typical dispersal distances in this species. Canonical rotation of the nonlinear selection matrices yielded similar conclusions as traditional nonlinear selection analyses, and also showed that the main axes of selection and fitness surfaces varied over space within the population. Our results emphasize the importance of quantifying different forms of selection, and of including variation in environmental conditions at small scales to gain a better understanding of potential evolutionary dynamics in wild populations. This study suggests that the fitness landscape for this species is relatively rugged at scales relevant to the life histories of in idual birds and their close relatives.
Publisher: MDPI AG
Date: 19-10-2020
DOI: 10.3390/JOF6040234
Abstract: Amphibians are currently the most threatened vertebrate class, with the disease chytridiomycosis being a major contributor to their global declines. Chytridiomycosis is a frequently fatal skin disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). The severity and extent of the impact of the infection caused by these pathogens across modern Amphibia are unprecedented in the history of vertebrate infectious diseases. The immune system of hibians is thought to be largely similar to that of other jawed vertebrates, such as mammals. However, hibian hosts are both ectothermic and water-dependent, which are characteristics favouring fungal proliferation. Although hibians possess robust constitutive host defences, Bd/Bsal replicate within host cells once these defences have been breached. Intracellular fungal localisation may contribute to evasion of the induced innate immune response. Increasing evidence suggests that once the innate defences are surpassed, fungal virulence factors suppress the targeted adaptive immune responses whilst promoting an ineffectual inflammatory cascade, resulting in immunopathology and systemic metabolic disruption. Thus, although infections are contained within the integument, crucial homeostatic processes become compromised, leading to mortality. In this paper, we present an integrated synthesis of hibian post-metamorphic immunological responses and the corresponding outcomes of infection with Bd, focusing on recent developments within the field and highlighting future directions.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 26-01-2018
Abstract: The comment by Myers-Smith and Myers focuses on three main points: (i) the lack of a mechanistic explanation for climate-selection relationships, (ii) the appropriateness of the climate data used in our analysis, and (iii) our focus on estimating climate-selection relationships across (rather than within) taxonomic groups. We address these critiques in our response.
Publisher: Springer Science and Business Media LLC
Date: 28-06-2007
DOI: 10.1038/NATURE05912
Abstract: Evolutionary theory predicts the depletion of genetic variation in natural populations as a result of the effects of selection, but genetic variation is nevertheless abundant for many traits that are under directional or stabilizing selection. Evolutionary geneticists commonly try to explain this paradox with mechanisms that lead to a balance between mutation and selection. However, theoretical predictions of equilibrium genetic variance under mutation-selection balance are usually lower than the observed values, and the reason for this is unknown. The potential role of sexually antagonistic selection in maintaining genetic variation has received little attention in this debate, surprisingly given its potential ubiquity in dioecious organisms. At fitness-related loci, a given genotype may be selected in opposite directions in the two sexes. Such sexually antagonistic selection will reduce the otherwise-expected positive genetic correlation between male and female fitness. Both theory and experimental data suggest that males and females of the same species may have ergent genetic optima, but supporting data from wild populations are still scarce. Here we present evidence for sexually antagonistic fitness variation in a natural population, using data from a long-term study of red deer (Cervus elaphus). We show that male red deer with relatively high fitness fathered, on average, daughters with relatively low fitness. This was due to a negative genetic correlation between estimates of fitness in males and females. In particular, we show that selection favours males that carry low breeding values for female fitness. Our results demonstrate that sexually antagonistic selection can lead to a trade-off between the optimal genotypes for males and females this mechanism will have profound effects on the operation of selection and the maintenance of genetic variation in natural populations.
Publisher: Springer Science and Business Media LLC
Date: 06-03-2018
Abstract: The fungal skin disease chytridiomycosis has caused the devastating decline and extinction of hundreds of hibian species globally, yet the potential for evolving resistance, and the underlying pathophysiological mechanisms remain poorly understood. We exposed 406 naïve, captive-raised alpine tree frogs ( Litoria verreauxii alpina ) from multiple populations (one evolutionarily naïve to chytridiomycosis) to the aetiological agent Batrachochytrium dendrobatidis in two concurrent and controlled infection experiments. We investigated (A) survival outcomes and clinical pathogen burdens between populations and clutches, and (B) in idual host tissue responses to chytridiomycosis. Here we present multiple interrelated datasets associated with these exposure experiments, including animal signalment, survival and pathogen burden of 355 animals from Experiment A, and the following datasets related to 61 animals from Experiment B: animal signalment and pathogen burden raw RNA-Seq reads from skin, liver and spleen tissues de novo assembled transcriptomes for each tissue type raw gene expression data annotation data for each gene and raw metabolite expression data from skin and liver tissues. These data provide an extensive baseline for future analyses.
Publisher: Springer Science and Business Media LLC
Date: 04-2015
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 02-2017
Publisher: Wiley
Date: 24-08-2021
DOI: 10.1111/EVO.14327
Abstract: The devastating infectious disease chytridiomycosis has caused declines of hibians across the globe, yet some populations are persisting and even recovering. One understudied effect of wildlife disease is changes in reproductive effort. Here, we aimed to understand if the disease has plastic effects on reproduction and if reproductive effort could evolve with disease endemism. We compared the effects of experimental pathogen exposure (trait plasticity) and population-level disease history (evolution in trait baseline) on reproductive effort using gametogenesis as a proxy in the declining and endangered frog Litoria verreauxii alpina. We found that unexposed males from disease-endemic populations had higher reproductive effort, which is consistent with an evolutionary response to chytridiomycosis. We also found evidence of trait plasticity, where males and females were affected differently by infection: pathogen exposed males had higher reproductive effort (larger testes), whereas females had reduced reproductive effort (smaller and fewer developed eggs) regardless of the population of origin. Infectious diseases can cause plastic changes in the reproductive effort at an in idual level, and population-level disease exposure can result in changes to baseline reproductive effort therefore, in idual- and population-level effects of disease should be considered when designing management and conservation programs for threatened and declining species.
Publisher: Wiley
Date: 2008
Publisher: Elsevier BV
Date: 04-2019
Publisher: Routledge
Date: 20-06-2017
Publisher: The Royal Society
Date: 04-2015
DOI: 10.1098/RSOS.150057
Abstract: Both social and ecological factors influence population process and structure, with resultant consequences for phenotypic selection on in iduals. Understanding the scale and relative contribution of these two factors is thus a central aim in evolutionary ecology. In this study, we develop a framework using null models to identify the social and spatial patterns that contribute to phenotypic structure in a wild population of songbirds. We used automated technologies to track 1053 in iduals that formed 73 737 groups from which we inferred a social network. Our framework identified that both social and spatial drivers contributed to assortment in the network. In particular, groups had a more even sex ratio than expected and exhibited a consistent age structure that suggested local association preferences, such as preferential attachment or avoidance. By contrast, recent immigrants were spatially partitioned from locally born in iduals, suggesting differential dispersal strategies by phenotype. Our results highlight how different scales of social decision-making, ranging from post-natal dispersal settlement to fission–fusion dynamics, can interact to drive phenotypic structure in animal populations.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.DCI.2022.104510
Abstract: Amphibians are among the vertebrate groups suffering great losses of bio ersity due to a variety of causes including diseases, such as chytridiomycosis (caused by the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans). The hibian metamorphic period has been identified as being particularly vulnerable to chytridiomycosis, with dramatic physiological and immunological reorganisation likely contributing to this vulnerability. Here, we overview the processes behind these changes at metamorphosis and then perform a systematic literature review to capture the breadth of empirical research performed over the last two decades on the metamorphic immune response. We found that few studies focused specifically on the immune response during the peri-metamorphic stages of hibian development and fewer still on the implications of their findings with respect to chytridiomycosis. We recommend future studies consider components of the immune system that are currently under-represented in the literature on hibian metamorphosis, particularly pathogen recognition pathways. Although logistically challenging, we suggest varying the timing of exposure to Bd across metamorphosis to examine the relative importance of pathogen evasion, suppression or dysregulation of the immune system. We also suggest elucidating the underlying mechanisms of the increased susceptibility to chytridiomycosis at metamorphosis and the associated implications for population persistence. For species that overlap a distribution where Bd/Bsal are now endemic, we recommend a greater focus on management strategies that consider the important peri-metamorphic period.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.AQUATOX.2022.106326
Abstract: Global wildfire events are projected to become more frequent and severe due to the continual threat of climate change, resulting in increasing demand for effective fire mitigation methods. Firefighting chemicals (FFCs), including retardants, foams and water enhancers, are often used to prevent the spread of wildfires. However, the impact of FFCs on wildlife and ecosystems is poorly understood. We investigated the effects of two common FFC formulations, Phos-Chek LC95W and BlazeTamer380, on tadpole survival, growth, development and swimming behaviour. Tadpoles of the striped marsh frog (Limnodynastes peronii) were exposed to two concentrations of either Phos-Chek (0.25 and 1 g/L) or BlazeTamer (0.05 and 0.2 g/L) for 16 days. The highest concentration of Phos-Chek was lethal to tadpoles, with mortalities gradually increasing over time and only 8% of animals surviving to day 16. Both FFCs influenced the growth and development of tadpoles, though effects were more severe in tadpoles exposed to the Phos-Chek formulation. Phos-Chek was found to completely stop tadpole growth and development over the 16-day exposure, whereas BlazeTamer significantly delayed growth and development in comparison to controls. Nevertheless, treatments had no apparent effect on tadpole movement patterns and swimming activity. Greater toxicity caused by the Phos-Chek treatment likely relates to the increased ammonia and altered water quality parameters. Runoff or accidental application of commonly used FFCs into small waterways may therefore have important ramifications for aquatic biota.
Publisher: Springer International Publishing
Date: 2018
Publisher: BMJ
Date: 02-2018
DOI: 10.1136/BMJOPEN-2017-016633
Abstract: Humans are by nature a social species, with much of human experience spent in social interaction. Unsurprisingly, social functioning is crucial to well-being and quality of life across the lifespan. While early intervention for social problems appears promising, our ability to identify the specific impairments underlying their social problems (eg, social communication) is restricted by a dearth of accurate, ecologically valid and comprehensive child-direct assessment tools. Current tools are largely limited to parent and teacher ratings scales, which may identify social dysfunction, but not its underlying cause, or adult-based experimental tools, which lack age-appropriate norms. The present study describes the development and standardisation of Paediatric Evaluation of Emotions, Relationships, and Socialisation ( PEERS®), an iPad-based social skills assessment tool. The PEERS project is a cross-sectional study involving two groups: (1) a normative group, recruited from early childhood, primary and secondary schools across metropolitan and regional Victoria, Australia and (2) a clinical group, ascertained from outpatient services at The Royal Children’s Hospital Melbourne (RCH). The project aims to establish normative data for PEERS®, a novel and comprehensive app-delivered child-direct measure of social skills for children and youth. The project involves recruiting and assessing 1000 children aged 4.0–17.11 years. Assessments consist of an intellectual screen, PEERS® subtests, and PEERS-Q, a self-report questionnaire of social skills. Parents and teachers also complete questionnaires relating to participants’ social skills. Main analyses will comprise regression-based continuous norming, factor analysis and psychometric analysis of PEERS® and PEERS-Q. Ethics approval has been obtained through the RCH Human Research Ethics Committee (34046), the Victorian Government Department of Education and Early Childhood Development (002318), and Catholic Education Melbourne (2166). Findings will be disseminated through international conferences and peer-reviewed journals. Following standardisation of PEERS®, the tool will be made commercially available.
Publisher: Wiley
Date: 04-12-2020
Abstract: The integration and synthesis of the data in different areas of science is drastically slowed and hindered by a lack of standards and networking programmes. Long‐term studies of in idually marked animals are not an exception. These studies are especially important as instrumental for understanding evolutionary and ecological processes in the wild. Furthermore, their number and global distribution provides a unique opportunity to assess the generality of patterns and to address broad‐scale global issues (e.g. climate change). To solve data integration issues and enable a new scale of ecological and evolutionary research based on long‐term studies of birds, we have created the SPI‐Birds Network and Database ( www.spibirds.org )—a large‐scale initiative that connects data from, and researchers working on, studies of wild populations of in idually recognizable (usually ringed) birds. Within year and a half since the establishment, SPI‐Birds has recruited over 120 members, and currently hosts data on almost 1.5 million in idual birds collected in 80 populations over 2,000 cumulative years, and counting. SPI‐Birds acts as a data hub and a catalogue of studied populations. It prevents data loss, secures easy data finding, use and integration and thus facilitates collaboration and synthesis. We provide community‐derived data and meta‐data standards and improve data integrity guided by the principles of Findable, Accessible, Interoperable and Reusable (FAIR), and aligned with the existing metadata languages (e.g. ecological meta‐data language). The encouraging community involvement stems from SPI‐Bird's decentralized approach: research groups retain full control over data use and their way of data management, while SPI‐Birds creates tailored pipelines to convert each unique data format into a standard format. We outline the lessons learned, so that other communities (e.g. those working on other taxa) can adapt our successful model. Creating community‐specific hubs (such as ours, COMADRE for animal demography, etc.) will aid much‐needed large‐scale ecological data integration.
Publisher: University of Chicago Press
Date: 2010
DOI: 10.1086/648604
Abstract: Best linear unbiased prediction (BLUP) is a method for obtaining point estimates of a random effect in a mixed effect model. Over the past decade it has been used extensively in ecology and evolutionary biology to predict in idual breeding values and reaction norms. These predictions have been used to infer natural selection, evolutionary change, spatial-genetic patterns, in idual reaction norms, and frailties. In this article we show analytically and through simulation and ex le why BLUP often gives anticonservative and biased estimates of evolutionary and ecological parameters. Although some concerns with BLUP methodology have been voiced before, the scale and breadth of the problems have probably not been widely appreciated. Bias arises because BLUPs are often used to estimate effects that are not explicitly accounted for in the model used to make the predictions. In these cases, predicted breeding values will often say more about phenotypic patterns than the genetic patterns of interest. An additional problem is that BLUPs are point estimates of quantities that are usually known with little certainty. Failure to account for this uncertainty in subsequent tests can lead to both bias and extreme anticonservatism. We demonstrate that restricted maximum likelihood and Bayesian solutions exist for these problems and show how unbiased and powerful tests can be derived that adequately quantify uncertainty. Of particular utility is a new test for detecting evolutionary change that not only accounts for prediction error in breeding values but also accounts for drift. To illustrate the problem, we apply these tests to long-term data on the Soay sheep (Ovis aries) and the great tit (Parus major) and show that previously reported temporal trends in breeding values are not supported.
Publisher: Springer Science and Business Media LLC
Date: 07-2001
DOI: 10.1038/35083580
Publisher: The Royal Society
Date: 17-05-2017
Abstract: Understanding the consequences of losing in iduals from wild populations is a current and pressing issue, yet how such loss influences the social behaviour of the remaining animals is largely unexplored. Through combining the automated tracking of winter flocks of over 500 wild great tits ( Parus major ) with removal experiments, we assessed how in iduals' social network positions responded to the loss of their social associates. We found that the extent of flockmate loss that in iduals experienced correlated positively with subsequent increases in the number of their social associations, the average strength of their bonds and their overall connectedness within the social network (defined as summed edge weights). Increased social connectivity was not driven by general disturbance or changes in foraging behaviour, but by modifications to fine-scale social network connections in response to losing their associates. Therefore, the reduction in social connectedness expected by in idual loss may be mitigated by increases in social associations between remaining in iduals. Given that these findings demonstrate rapid adjustment of social network associations in response to the loss of previous social ties, future research should examine the generality of the compensatory adjustment of social relations in ways that maintain the structure of social organization.
Publisher: The Royal Society
Date: 22-04-2015
Abstract: The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its hibian hosts. Responses of in iduals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected hibians. We found that Bd-resistant hibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine hibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing hibian bio ersity will depend on our understanding of hibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal.
Publisher: Public Library of Science (PLoS)
Date: 20-12-2018
Publisher: Wiley
Date: 06-02-2015
DOI: 10.1111/JEB.12587
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CUB.2015.09.075
Abstract: Social relationships are fundamental to animals living in complex societies. The extent to which in iduals base their decisions around their key social relationships, and the consequences this has on their behavior and broader population level processes, remains unknown. Using a novel experiment that controlled where in idual wild birds (great tits, Parus major) could access food, we restricted mated pairs from being allowed to forage at the same locations. This introduced a conflict for pair members between maintaining social relationships and accessing resources. We show that in iduals reduce their own access to food in order to sustain their relationships and that in idual foraging activity was strongly influenced by their key social counterparts. By affecting where in iduals go, social relationships determined which conspecifics they encountered and consequently shaped their other social associations. Hence, while resource distribution can determine in iduals' spatial and social environment, we illustrate how key social relationships themselves can govern broader social structure. Finally, social relationships also influenced the development of social foraging strategies. In response to forgoing access to resources, maintaining pair bonds led in iduals to develop a flexible "scrounging" strategy, particularly by scrounging from their pair mate. This suggests that behavioral plasticity can develop to ameliorate conflicts between social relationships and other demands. Together, these results illustrate the importance of considering social relationships for explaining behavioral variation due to their significant impact on in idual behavior and demonstrate the consequences of key relationships for wider processes.
Publisher: The Royal Society
Date: 06-2016
Abstract: Animals regularly use information from others to shape their decisions. Yet, determining how changes in social structure affect information flow and social learning strategies has remained challenging. We manipulated the social structure of a large community of wild songbirds by controlling which in iduals could feed together at automated feeding stations (selective feeders). We then provided novel ephemeral food patches freely accessible to all birds and recorded the spread of this new information. We demonstrate that the discovery of new food patches followed the experimentally imposed social structure and that birds disproportionately learnt from those whom they could forage with at the selective feeders. The selective feeders reduced the number of conspecific information sources available and birds subsequently increased their use of information provided by heterospecifics. Our study demonstrates that changes to social systems carry over into pathways of information transfer and that in iduals learn from tutors that provide relevant information in other contexts.
Publisher: Wiley
Date: 27-10-2023
DOI: 10.1002/EAP.2724
Abstract: Novel infectious diseases, particularly those caused by fungal pathogens, pose considerable risks to global bio ersity. The hibian chytrid fungus ( Batrachochytrium dendrobatidis , Bd ) has demonstrated the scale of the threat, having caused the greatest recorded loss of vertebrate bio ersity attributable to a pathogen. Despite catastrophic declines on several continents, many affected species have experienced population recoveries after epidemics. However, the potential ongoing threat of endemic Bd in these recovered or recovering populations is still poorly understood. We investigated the threat of endemic Bd to frog populations that recovered after initial precipitous declines, focusing on the endangered rainforest frog Mixophyes fleayi . We conducted extensive field surveys over 4 years at three independent sites in eastern Australia. First, we compared Bd infection prevalence and infection intensities within frog communities to reveal species‐specific infection patterns. Then, we analyzed mark‐recapture data of M. fleayi to estimate the impact of Bd infection intensity on apparent mortality rates and Bd infection dynamics. We found that M. fleayi had lower infection intensities than sympatric frogs across the three sites, and cleared infections at higher rates than they gained infections throughout the study period. By incorporating time‐varying in idual infection intensities, we show that healthy M. fleayi populations persist despite increased apparent mortality associated with infrequent high Bd loads. Infection dynamics were influenced by environmental conditions, with Bd prevalence, infection intensity, and rates of gaining infection associated with lower temperatures and increased rainfall. However, mortality remained constant year‐round despite these fluctuations in Bd infections, suggesting major mortality events did not occur over the study period. Together, our results demonstrate that while Bd is still a potential threat to recovered populations of M. fleayi , high rates of clearing infections and generally low average infection loads likely minimize mortality caused by Bd . Our results are consistent with pathogen resistance contributing to the coexistence of M. fleayi with endemic Bd . We emphasize the importance of incorporating infection intensity into disease models rather than infection status alone. Similar population and infection dynamics likely exist within other recovered hibian‐ Bd systems around the globe, promising longer‐term persistence in the face of endemic chytridiomycosis.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-05-2022
Abstract: The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in in idual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.
Publisher: Frontiers Media SA
Date: 09-11-2018
Publisher: Springer Science and Business Media LLC
Date: 03-12-2014
DOI: 10.1038/NATURE13998
Publisher: Hindawi Limited
Date: 13-08-2019
DOI: 10.1111/CMI.13089
Abstract: Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a skin disease responsible for the global decline of hibians. Frog species and populations can vary in susceptibility, but this phenomenon remains poorly understood. Here, we investigated serotonin in the skin of infected and uninfected frogs. In more susceptible frog populations, skin serotonin rose with increasing infection intensity, but decreased in later stages of the disease. The more resistant population maintained a basal level of skin serotonin. Serotonin inhibited both Bd sporangial growth and Jurkat lymphocyte proliferation in vitro. However, serotonin accumulates in skin granular glands, and this compartmentalisation may prevent inhibition of Bd growth in vivo. We suggest that skin serotonin increases in susceptible frogs due to pathogen excretion of precursor tryptophan, but that resistant frogs are able to control the levels of serotonin. Overall, the immunosuppressive effects of serotonin may contribute to the susceptibility of frogs to chytridiomycosis.
Publisher: Elsevier BV
Date: 11-2017
Publisher: The Royal Society
Date: 27-02-2019
Abstract: Wintering songbirds have been widely shown to make economic foraging decisions to manage the changing balance of risks from predation and starvation over the course of the day. In this study, we ask whether the communication and use of information about food availability differ throughout the day. First, we assessed temporal variation in food-related vocal information produced in foraging flocks of tits ( Paridae ) using audio recordings at radio-frequency identification-equipped feeding stations. Vocal activity was highest in the morning and decreased into the afternoon. This pattern was not explained by there being fewer birds present, as we found that group sizes increased over the course of the day. Next, we experimentally tested the underlying causes for this diurnal calling pattern. We set up bird feeders with or without playback of calls from tits, either in the morning or in the afternoon, and compared latency to feeder discovery, accumulation of flock members, and total number of birds visiting the feeder. Irrespective of time of day, playbacks had a strong effect on all three response measures when compared to silent control trials, demonstrating that tits will readily use vocal information to improve food detection throughout the day. Thus, the diurnal pattern of foraging behaviour did not appear to affect use and production of food-related vocalizations. Instead, we suggest that, as the day progresses and foraging group sizes increase, the costs of producing calls at the food source (e.g. competition and attraction of predators) outweigh the benefits of recruiting group members (i.e. adding in iduals to large groups only marginally increases safety in numbers), causing the observed decrease in vocal activity into the afternoon. Our findings imply that in iduals make economic social adjustments based on conditions of their social environment when deciding to vocally recruit group members.
Publisher: The Royal Society
Date: 22-03-2015
Abstract: Understanding the functional links between social structure and population processes is a central aim of evolutionary ecology. Multiple types of interactions can be represented by networks drawn for the same population, such as kinship, dominance or affiliative networks, but the relative importance of alternative networks in modulating population processes may not be clear. We illustrate this problem, and a solution, by developing a framework for testing the importance of different types of association in facilitating the transmission of information. We apply this framework to experimental data from wild songbirds that form mixed-species flocks, recording the arrival (patch discovery) of in iduals to novel foraging sites. We tested whether intraspecific and interspecific social networks predicted the spread of information about novel food sites, and found that both contributed to transmission. The likelihood of acquiring information per unit of connection to knowledgeable in iduals increased 22-fold for conspecifics, and 12-fold for heterospecifics. We also found that species varied in how much information they produced, suggesting that some species play a keystone role in winter foraging flocks. More generally, these analyses demonstrate that this method provides a powerful approach, using social networks to quantify the relative transmission rates across different social relationships.
Publisher: CSIRO Publishing
Date: 18-07-2022
DOI: 10.1071/WR21181
Abstract: Context Records collected when sick, injured or dead animals arrive at wildlife care facilities have potential to offer insights into population declines and identify key threatening processes for conservation and management intervention. Aims Records compiled from a centralised Queensland Government database of koala (Phascolarctus cinereus) arrivals to care facilities across South East Queensland were analysed to explore long- and short-term trends in arrivals in terms of seasonality, causes, outcomes and spatial distribution, with a particular focus on insights hospital records could provide into the potential role of disease in koala population declines. Methods Analysis was conducted on over 22 years of records of koalas arriving at care facilities collated by the Queensland Government. We summarised causes of hospital arrivals and outcomes. We utilised time-series methods to explore short-term cyclic dynamics in the data, and spatial tools to document changes in the distribution of koala arrivals. Key results In the long term, koala hospital arrivals increased modestly from 1997 to 2014, before falling into decline by 2018. Long-term changes are dwarfed by short-term fluctuations, including clear annual cyclic dynamics associated with car strike and dog attack, which peak from August to October each year, likely coinciding with the onset of the koala breeding season. Seasonality is also detected in disease-associated arrivals. Known severe declines in wild koala populations in South East Queensland, an area of intensive urbanisation and associated loss of koala habitat, are not reflected in the overall koala hospital arrival numbers. Our analysis suggests that severe local declines in wild koala abundance have been obscured by increases in the catchment areas from which koalas are entering the hospital network. Conclusions Koala hospital records provide an extensive dataset that can be mined for insights into koala population dynamics and threatening processes. However, interpretation of our findings must consider limitations and biases inherent in data collection. Implications Despite acknowledged shortcomings in terms of bias and data quality, retrospective analysis of records from care facilities can provide important insights for guiding conservation efforts. For ex le, our findings with respect to seasonality in koala hospital arrivals mirror results reported for other locales, suggesting that cyclic dynamics are not a local phenomenon, but occur more broadly across the species range, with implications for seasonal delivery of conservation actions.
Publisher: Public Library of Science (PLoS)
Date: 29-05-2014
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-07-2020
Abstract: Integrating comparative immunology can improve human, animal, and ecosystem health
Publisher: American Physiological Society
Date: 03-2010
DOI: 10.1152/AJPREGU.00729.2009
Abstract: Transepithelial fluid secretion across the renal (Malpighian) tubule epithelium of the mosquito ( Aedes aegypti ) is energized by the vacuolar-type (V-type) H + -ATPase and not the Na + -K + -ATPase. Located at the apical membrane of principal cells, the V-type H + -ATPase translocates protons from the cytoplasm to the tubule lumen. Secreted protons are likely to derive from metabolic H 2 CO 3 , which raises questions about the handling of HCO 3 − by principal cells. Accordingly, we tested the hypothesis that a Cl/HCO 3 anion exchanger (AE) related to the solute-linked carrier 4 (SLC4) superfamily mediates the extrusion of HCO 3 − across the basal membrane of principal cells. We began by cloning from Aedes Malpighian tubules a full-length cDNA encoding an SLC4-like AE, termed AeAE. When expressed heterologously in Xenopus oocytes, AeAE is both N- and O-glycosylated and mediates Na + -independent intracellular pH changes that are sensitive to extracellular Cl − concentration and to DIDS. In Aedes Malpighian tubules, AeAE is expressed as two distinct forms: one is O-glycosylated, and the other is N-glycosylated. Significantly, AeAE immunoreactivity localizes to the basal regions of stellate cells but not principal cells. Concentrations of DIDS that inhibit AeAE activity in Xenopus oocytes have no effects on the unstimulated rates of fluid secretion mediated by Malpighian tubules as measured by the Ramsay assay. However, in Malpighian tubules stimulated with kinin or calcitonin-like diuretic peptides, DIDS reduces the diuretic rates of fluid secretion to basal levels. In conclusion, Aedes Malpighian tubules express AeAE in the basal region of stellate cells, where this transporter may participate in producing diuretic rates of transepithelial fluid secretion.
Publisher: Elsevier BV
Date: 09-2014
Publisher: The Royal Society
Date: 07-08-2002
Publisher: Cold Spring Harbor Laboratory
Date: 28-09-2019
DOI: 10.1101/784777
Abstract: Animals use behavioural cues from others to make decisions in a variety of contexts. There is growing evidence, from a range of taxa, that information about the locations of food patches can spread through a population via social connections. However, it is not known whether information about the quality of potential food sources transmits similarly. We studied foraging behaviour in a population of wild songbirds with known social associations, and tested whether flock members use social information about the profitability of patches to inform their foraging decisions. We provided artificial patches (ephemeral bird feeders) that appeared identical but were either profitable (contained food) or unprofitable (contained no food). If information about patch profitability spreads via social associations, we predicted that empty feeders would only be s led by in iduals that are less connected to each other than expected by chance. In contrast, we found that in iduals recorded at empty feeders were more closely associated with each other than predicted by a null model simulating random arrival of in iduals, mirroring pattern of increased connectedness among in iduals recorded at full feeders. We then simulated arrival under network-based diffusion of information, and demonstrate that the observed pattern at both full and empty feeders matches predictions derived from this post-hoc model. Our results suggest that foraging songbirds only use social cues about the location of potential food sources, but not their profitability. These findings agree with the hypothesis that in iduals balance the relative economic costs of using different information, where the costs of personally s ling a patch upon arrival is low relative to the cost of searching for patches. This study extends previous work on information spread through avian social networks, by suggesting important links between how animals use information at different stages of the acquisition process and the emerging population-level patterns of patch use.
Publisher: Wiley
Date: 16-05-2013
DOI: 10.1111/COBI.12073
Abstract: Assessing the effects of diseases on wildlife populations can be difficult in the absence of observed mortalities, but it is crucial for threat assessment and conservation. We performed an intensive capture-mark-recapture study across seasons and years to investigate the effect of chytridiomycosis on demographics in 2 populations of the threatened common mist frog (Litoria rheocola) in the lowland wet tropics of Queensland, Australia. Infection prevalence was the best predictor for apparent survival probability in adult males and varied widely with season (0-65%). Infection prevalence was highest in winter months when monthly survival probabilities were low (approximately 70%). Populations at both sites exhibited very low annual survival probabilities (12-15%) but high recruitment (71-91%), which resulted in population growth rates that fluctuated seasonally. Our results suggest that even in the absence of observed mortalities and continued declines, and despite host-pathogen co-existence for multiple host generations over almost 2 decades, chytridiomycosis continues to have substantial seasonally fluctuating population-level effects on hibian survival, which necessitates increased recruitment for population persistence. Similarly infected populations may thus be under continued threat from chytridiomycosis which may render them vulnerable to other threatening processes, particularly those affecting recruitment success.
Publisher: Wiley
Date: 21-12-2022
DOI: 10.1002/ECY.3908
Abstract: Identifying the environmental drivers of variation in fitness‐related traits is a central objective in ecology and evolutionary biology. Temporal fluctuations of these environmental drivers are often synchronized at large spatial scales. Yet, whether synchronous environmental conditions can generate spatial synchrony in fitness‐related trait values (i.e., correlated temporal trait fluctuations across populations) is poorly understood. Using data from long‐term monitored populations of blue tits ( Cyanistes caeruleus , n = 31), great tits ( Parus major , n = 35), and pied flycatchers ( Ficedula hypoleuca , n = 20) across Europe, we assessed the influence of two local climatic variables (mean temperature and mean precipitation in February–May) on spatial synchrony in three fitness‐related traits: laying date, clutch size, and fledgling number. We found a high degree of spatial synchrony in laying date but a lower degree in clutch size and fledgling number for each species. Temperature strongly influenced spatial synchrony in laying date for resident blue tits and great tits but not for migratory pied flycatchers. This is a relevant finding in the context of environmental impacts on populations because spatial synchrony in fitness‐related trait values among populations may influence fluctuations in vital rates or population abundances. If environmentally induced spatial synchrony in fitness‐related traits increases the spatial synchrony in vital rates or population abundances, this will ultimately increase the risk of extinction for populations and species. Assessing how environmental conditions influence spatiotemporal variation in trait values improves our mechanistic understanding of environmental impacts on populations.
Publisher: Wiley
Date: 17-09-2013
DOI: 10.1111/ELE.12181
Abstract: Social environments have an important effect on a range of ecological processes, and form a crucial component of selection. However, little is known of the link between personality, social behaviour and population structure. We combine a well-understood personality trait with large-scale social networks in wild songbirds, and show that personality underpins multiple aspects of social organisation. First, we demonstrate a relationship between network centrality and personality with 'proactive' (fast-exploring) in iduals associating weakly with greater numbers of conspecifics and moving between flocks. Second, temporal stability of associations relates to personality: 'reactive' (slow-exploring) birds form synergistically stable relationships. Finally, we show that personality influences social structure, with males non-randomly distributed across groups. These results provide strong evidence that songbirds follow alternative social strategies related to personality. This has implications not only for the causes of social network structure but also for the strength and direction of selection on personality in natural populations.
Publisher: Elsevier BV
Date: 05-2003
Publisher: Elsevier BV
Date: 10-2021
Publisher: Wiley
Date: 16-10-2020
DOI: 10.1111/ELE.13621
Publisher: Cold Spring Harbor Laboratory
Date: 24-08-2019
DOI: 10.1101/746545
Abstract: Natural populations and communities consist of in iduals that differ in their phenotypes. There is increasing evidence in community ecology that consistent intraspecific variation in behaviour changes the outcome of ecological interactions. Differences in intra- and inter-specific interactions are expected to play a major role in determining patterns of species coexistence and community structure. However, the question of whether in iduals vary in their propensity to associate with heterospecifics has been neglected. We used social network analysis to characterise pattern of heterospecific associations in wild mixed-species flocks of songbirds, and assessed whether in iduals adopt consistent social strategies in their broader, heterospecific, social environment. We quantified heterospecific foraging associations using data from a large automatically monitored PIT-tagged population of birds, involving more than 300 000 observations of flock membership, collected over three winters, for two tit species (Paridae), blue tits, Cyanistes caeruleus , and great tits, Parus major . We assessed in idual consistency in interspecific social preferences over both short-term (week-to-week) and longer-term (year-to-year) timescales for a total of 4610 in iduals, and found that blue tits and great tits exhibited marked and consistent intraspecific differences in heterospecific social phenotypes in terms of both absolute and relative number of associates. Further, we found that these consistent differences were significantly greater than expected from spatial and temporal differences in population densities. Heterospecific associations represent a major component of the social environment for many species, and our results show that in iduals vary consistently in their social decisions with respect to heterospecifics. These findings provide support for the notion that intraspecific trait variation contributes to patterns at community and ecosystem levels.
Publisher: Springer Science and Business Media LLC
Date: 08-11-2022
Publisher: Springer Science and Business Media LLC
Date: 2001
Publisher: The Royal Society
Date: 12-06-2023
Abstract: Animal defences against infection involve two distinct but complementary mechanisms: tolerance and resistance. Tolerance measures the animal's ability to limit detrimental effects from a given infection, whereas resistance is the ability to limit the intensity of that infection. Tolerance is a valuable defence for highly prevalent, persistent or endemic infections where mitigation strategies based on traditional resistance mechanisms are less effective or evolutionarily stable. Selective breeding of hibians for enhanced tolerance to Batrachochytrium spp . has been suggested as a strategy for mitigating the impacts of the fungal disease, chytridiomycosis. Here, we define infection tolerance and resistance in the context of chytridiomycosis, present evidence for variation in tolerance to chytridiomycosis, and explore epidemiological, ecological and evolutionary implications of tolerance to chytridiomycosis. We found that exposure risk and environmental moderation of infection burdens are major confounders of resistance and tolerance, chytridiomycosis is primarily characterized by variation in constitutive rather than adaptive resistance, tolerance is epidemiologically important in driving pathogen spread and maintenance, heterogeneity of tolerance leads to ecological trade-offs, and natural selection for resistance and tolerance is likely to be dilute. Improving our understanding of infection tolerance broadens our capacity for mitigating the ongoing impacts of emerging infectious diseases such as chytridiomycosis. This article is part of the theme issue ‘Amphibian immunity: stress, disease and ecoimmunology’.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-03-2017
Abstract: Climate change will fundamentally alter many aspects of the natural world. To understand how species may adapt to this change, we must understand which aspects of the changing climate exert the most powerful selective forces. Siepielski et al. looked at studies of selection across species and regions and found that, across biomes, the strongest sources of selection were precipitation and transpiration changes. Importantly, local and regional climate change explained patterns of selection much more than did global change. Science , this issue p. 959
Publisher: University of Chicago Press
Date: 12-2001
DOI: 10.1086/323585
Abstract: One of evolutionary biology's most persistent puzzles is the fact that apparent directional selection on a heritable trait in a natural population often does not produce a selection response. We tested three possible explanations for this problem using data on body size of more than 23,000 in iduals, measured over 18 yr, in a collared flycatcher (Ficedula albicollis) population. Using a restricted maximum likelihood "animal model," we found a narrow-sense heritability for fledgling tarsus length of [Formula: see text] SE and substantial common environment effects ([Formula: see text] SE). For survival to adulthood, the selection differential on tarsus length was [Formula: see text] SE. There was, however, no response to this selection over the study period. One explanation for the lack of response might have been that selection was associated with only the environmental (nonheritable) component of phenotype, but we found significant selection on breeding values (the heritable component). There was also no evidence of fluctuating selection pressures or of antagonistic selection between the sexes in selection pressures. Thus, in contrast to earlier investigations in this same population, none of the potential explanations for the absence of a selection response was supported we discuss alternative hypotheses yet to be investigated.
Publisher: Cold Spring Harbor Laboratory
Date: 16-08-2020
DOI: 10.1101/2020.08.16.252379
Abstract: The phenology of many species shows strong sensitivity to climate change however, with few large scale intra-specific studies it is unclear how such sensitivity varies over a species’ range. We document large intra-specific variation in phenological sensitivity to temperature using laying date information from 67 populations of two European songbirds covering a large part of their breeding range. Populations inhabiting deciduous habitats showed stronger phenological sensitivity compared with those in evergreen and mixed habitats. Strikingly, however, the lowest sensitivity was seen in populations that had experienced the greatest change in climate. Therefore, we predict that the strongest phenological advancement will not occur in those populations with the highest sensitivity. Our results show that to effectively assess the impact of climate change on phenology across a species range it will be necessary to account for intra-specific variation in phenological sensitivity, climate change exposure, and the ecological characteristics of a population.
Publisher: Springer Science and Business Media LLC
Date: 19-04-2022
DOI: 10.1038/S41467-022-29635-4
Abstract: The phenology of many species shows strong sensitivity to climate change however, with few large scale intra-specific studies it is unclear how such sensitivity varies over a species’ range. We document large intra-specific variation in phenological sensitivity to temperature using laying date information from 67 populations of two co-familial European songbirds, the great tit ( Parus major ) and blue tit ( Cyanistes caeruleus ), covering a large part of their breeding range. Populations inhabiting deciduous habitats showed stronger phenological sensitivity than those in evergreen and mixed habitats. However, populations with higher sensitivity tended to have experienced less rapid change in climate over the past decades, such that populations with high phenological sensitivity will not necessarily exhibit the strongest phenological advancement. Our results show that to effectively assess the impact of climate change on phenology across a species’ range it will be necessary to account for intra-specific variation in phenological sensitivity, climate change exposure, and the ecological characteristics of a population.
Publisher: Springer Science and Business Media LLC
Date: 29-05-2018
DOI: 10.1038/S41598-018-26427-Z
Abstract: Chytridiomycosis is among several recently emerged fungal diseases of wildlife that have caused decline or extinction of naïve populations. Despite recent advances in understanding pathogenesis, host response to infection remains poorly understood. Here we modelled a total of 162 metabolites across skin and liver tissues of 61 frogs from four populations (three long-exposed and one naïve to the fungus) of the Australian alpine tree frog ( Litoria verreauxii alpina ) throughout a longitudinal exposure experiment involving both infected and negative control in iduals. We found that chytridiomycosis dramatically altered the organism-wide metabolism of clinically diseased frogs. Chytridiomycosis caused catastrophic failure of normal homeostatic mechanisms (interruption of biosynthetic and degradation metabolic pathways), and pronounced dysregulation of cellular energy metabolism. Key intermediates of the tricarboxylic acid cycle were markedly depleted, including in particular α-ketoglutarate and glutamate that together constitute a key nutrient pathway for immune processes. This study was the first to apply a non-targeted metabolomics approach to a fungal wildlife disease and specifically to dissect the host-pathogen interface of Bd-infected frogs. The patterns of metabolite accumulation we have identified reveal whole-body metabolic dysfunction induced by a fungal skin infection, and these findings have broad relevance for other fungal diseases.
Start Date: 12-2020
End Date: 12-2024
Amount: $426,742.00
Funder: Australian Research Council
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