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1.
Nat Ecol Evol ; 4(1): 148-155, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31659308

RESUMO

The survival of a bird's developing embryo depends on the egg's ability to stay within strict thermal limits. How eggshell colours help maintain thermal balance is a long-standing and contested question. Using data spanning a wide phylogenetic diversity of birds on a global spatial scale, we find evidence that eggshell pigmentation may have been shaped by thermoregulatory needs. Birds living in cold habitats, particularly those with nests exposed to incident solar radiation, have darker eggs. We show evidence that darker eggs heat more rapidly than lighter ones when exposed to solar radiation. This evidence suggests that egg pigmentation could play an important role in thermoregulation in cold climates, while a range of competing selective pressures further influence eggshell colours in warmer climates. These findings advance our understanding of thermoregulation in the distribution of natural colours.

2.
Sci Rep ; 9(1): 15892, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31664048

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

3.
Curr Biol ; 29(19): R977-R982, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31593680

RESUMO

The last decade has transformed the field of artificial intelligence, with deep learning at the forefront of this development. With its ability to 'self-learn' discriminative patterns directly from data, deep learning is a promising computational approach for automating the classification of visual, spatial and acoustic information in the context of environmental conservation. Here, we first highlight the current and future applications of supervised deep learning in environmental conservation. Next, we describe a number of technical and implementation-related challenges that can potentially impede the real-world adoption of this technology in conservation programmes. Lastly, to mitigate these pitfalls, we discuss priorities for guiding future research and hope that these recommendations will help make this technology more accessible to environmental scientists and conservation practitioners.

4.
Mar Environ Res ; 151: 104777, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31548093

RESUMO

Global warming and ocean acidification alter a wide range of animal behaviours, yet the effect on resource competition among species is poorly understood. We tested whether the combination of moderate levels of ocean acidification and warming altered the feeding success of co-occurring native, alien, and range-extending crab species, and how these changes affected their hierarchical dominance. Under contemporary conditions the range-extending species spent more time feeding, than the alien and the native species. Under conditions simulating future climate there was no difference in the proportion of time spent feeding among the three species. These behavioural changes translated to alterations in their dominance hierarchy (based on feeding success) with the most dominant species under present day conditions becoming less dominant under future conditions, and vice versa for the least dominant species. While empirical studies have predicted either reversal or strengthening of hierarchical dominance in animal species, we suggest that even moderate increases in ocean temperature and acidification can drive a homogenisation in behavioural competitiveness, eroding dominance differences among species that are linked to fitness-related traits in nature and hence important for their population persistence.

5.
Elife ; 82019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30767891

RESUMO

Self-replicating gene drives that modify sex ratios or infer a fitness cost could be used to control populations of invasive alien species. The targeted deletion of Y sex chromosomes using CRISPR technology offers a new approach for sex bias that could be incorporated within gene-drive designs. We introduce a novel gene-drive strategy termed Y-CHromosome deletion using Orthogonal Programmable Endonucleases (Y-CHOPE), incorporating a programmable endonuclease that 'shreds' the Y chromosome, thereby converting XY males into fertile XO females. Firstly, we demonstrate that the CRISPR/Cas12a system can eliminate the Y chromosome in embryonic stem cells with high efficiency (c. 90%). Next, using stochastic, individual-based models of a pest mouse population, we show that a Y-shredding drive that progressively depletes the pool of XY males could effect population eradication through mate limitation. Our molecular and modeling data suggest that a Y-CHOPE gene drive could be a viable tool for vertebrate pest control.

6.
Risk Anal ; 39(1): 35-53, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-28796311

RESUMO

Understanding the risk of biological invasions associated with particular transport pathways and source regions is critical for implementing effective biosecurity management. This may require both a model for physical connectedness between regions, and a measure of environmental similarity, so as to quantify the potential for a species to be transported from a given region and to survive at a destination region. We present an analysis of integrated biosecurity risk into Australia, based on flights and shipping data from each global geopolitical region, and an adaptation of the "range bagging" method to determine environmental matching between regions. Here, we describe global patterns of environmental matching and highlight those regions with many physical connections. We classify patterns of global invasion risk (high to low) into Australian states and territories. We validate our analysis by comparison with global presence data for 844 phytophagous insect pest species, and produce a list of high-risk species not previously known to be present in Australia. We determined that, of the insect pest species used for validation, the species most likely to be present in Australia were those also present in geopolitical regions with high transport connectivity to Australia, and those regions that were geographically close, and had similar environments.


Assuntos
Insetos , Medição de Risco/métodos , Viagem Aérea , Animais , Austrália , Meio Ambiente , Geografia , Espécies Introduzidas , Modelos Biológicos , Reprodutibilidade dos Testes , Navios
8.
J Exp Biol ; 221(Pt 23)2018 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-30322979

RESUMO

Accelerometers are a valuable tool for studying animal behaviour and physiology where direct observation is unfeasible. However, giving biological meaning to multivariate acceleration data is challenging. Here, we describe a method that reliably classifies a large number of behaviours using tri-axial accelerometer data collected at the low sampling frequency of 1 Hz, using the dingo (Canis dingo) as an example. We used out-of-sample validation to compare the predictive performance of four commonly used classification models (random forest, k-nearest neighbour, support vector machine, and naïve Bayes). We tested the importance of predictor variable selection and moving window size for the classification of each behaviour and overall model performance. Random forests produced the highest out-of-sample classification accuracy, with our best-performing model predicting 14 behaviours with a mean accuracy of 87%. We also investigated the relationship between overall dynamic body acceleration (ODBA) and the activity level of each behaviour, given the increasing use of ODBA in ecophysiology as a proxy for energy expenditure. ODBA values for our four 'high activity' behaviours were significantly greater than all other behaviours, with an overall positive trend between ODBA and intensity of movement. We show that a random forest model of relatively low complexity can mitigate some major challenges associated with establishing meaningful ecological conclusions from acceleration data. Our approach has broad applicability to free-ranging terrestrial quadrupeds of comparable size. Our use of a low sampling frequency shows potential for deploying accelerometers over extended time periods, enabling the capture of invaluable behavioural and physiological data across different ontogenies.


Assuntos
Acelerometria/métodos , Comportamento Animal , Canidae/fisiologia , Animais , Teorema de Bayes , Masculino , Tecnologia de Sensoriamento Remoto , Máquina de Vetores de Suporte , Gravação em Vídeo
9.
Math Biosci ; 305: 160-169, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30219282

RESUMO

Synthetic gene drives offer a novel solution for the control of invasive alien species. CRISPR-based gene drives can positively bias their own inheritance, and comprise a DNA sequence that is replicated by homologous recombination. Since gene drives can be positioned to silence fertility or developmental genes, they could be used for population suppression. However, the production of resistant alleles following self-replication errors threatens the technology's viability for pest eradication in real-world applications. Further, a robust assessment of how pest demography impacts the expected progression of gene drives through populations is currently lacking. We used a deterministic, two-sex, birth-death model to investigate how demographic assumptions affect the efficiency of suppression drives for controlling invasive rodents on islands, for two different gene-drive strategies. We show that mass-action reproduction results in overly optimistic eradication outcomes when compared to the more realistic assumption of polygynous breeding. When polygyny was assumed, both gene-strategies failed due to the evolution of resistance unless a reproductive Allee effect (reduced reproductive rates at low population density) was also included; although model outcomes were highly sensitive to the strength of this effect. Increasing the size of the initial gene-drive introduction (up to 10% of carrying capacity) had little impact on population outcomes. Understanding the demography of a population targeted for eradication is critical before the viability of gene-drive suppression can be adequately assessed.


Assuntos
Genes Sintéticos , Espécies Introduzidas , Modelos Genéticos , Animais , Biodiversidade , Simulação por Computador , Feminino , Genética Populacional , Masculino , Conceitos Matemáticos , Camundongos , Controle Biológico de Vetores/métodos , Controle Biológico de Vetores/estatística & dados numéricos , Controle da População/métodos , Controle da População/estatística & dados numéricos , Densidade Demográfica , Gravidez , Reprodução
10.
Proc Natl Acad Sci U S A ; 115(37): 9270-9275, 2018 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-30158167

RESUMO

One of the best-known general patterns in island biogeography is the species-isolation relationship (SIR), a decrease in the number of native species with increasing island isolation that is linked to lower rates of natural dispersal and colonization on remote oceanic islands. However, during recent centuries, the anthropogenic introduction of alien species has increasingly gained importance and altered the composition and richness of island species pools. We analyzed a large dataset for alien and native plants, ants, reptiles, mammals, and birds on 257 (sub) tropical islands, and showed that, except for birds, the number of naturalized alien species increases with isolation for all taxa, a pattern that is opposite to the negative SIR of native species. We argue that the reversal of the SIR for alien species is driven by an increase in island invasibility due to reduced diversity and increased ecological naiveté of native biota on the more remote islands.


Assuntos
Espécies Introduzidas , Ilhas , Modelos Biológicos , Clima Tropical
11.
J Anim Ecol ; 87(5): 1418-1428, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30133819

RESUMO

European rabbits (Oryctolagus cuniculus) have been exposed to rabbit haemorrhagic disease virus (RHDV) and myxoma virus (MYXV) in their native and invasive ranges for decades. Yet, the long-term effects of these viruses on rabbit population dynamics remain poorly understood. In this context, we analysed 17 years of detailed capture-mark-recapture data (2000-2016) from Turretfield, South Australia, using a probabilistic state-space hierarchical modelling framework to estimate rabbit survival and epidemiological dynamics. While RHDV infection and disease-induced death were most prominent during annual epidemics in winter and spring, we found evidence for continuous infection of susceptible individuals with RHDV throughout the year. RHDV-susceptible rabbits had, on average, 25% lower monthly survival rates compared to immune individuals, while the average monthly force of infection in winter and spring was ~38%. These combined to result in an average infection-induced mortality rate of 69% in winter and spring. Individuals susceptible to MYXV and immune to RHDV had similar survival probabilities to those having survived infections from both viruses, whereas individuals susceptible to both RHDV and MYXV had higher survival probabilities than those susceptible to RHDV and immune to MYXV. This suggests that MYXV may reduce the future survival rates of individuals that endure initial MYXV infection. There was no evidence for long-term changes in disease-induced mortality and infection rates for either RHDV or MYXV. We conclude that continuous, year-round virus perpetuation (and perhaps heterogeneity in modes of transmission and infectious doses during and after epidemics) acts to reduce the efficiency of RHDV and MYXV as biocontrol agents of rabbits in their invasive range. However, if virulence can be maintained as relatively constant through time, RHDV and MYXV will likely continue realizing strong benefits as biocontrol agents.


Assuntos
Infecções por Caliciviridae , Vírus da Doença Hemorrágica de Coelhos , Myxoma virus , Animais , Coelhos , Austrália do Sul , Virulência
12.
Sci Rep ; 8(1): 8843, 2018 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-29891968

RESUMO

Environmental DNA (eDNA) metabarcoding can greatly enhance our understanding of global biodiversity and our ability to detect rare or cryptic species. However, sampling effort must be considered when interpreting results from these surveys. We explored how sampling effort influenced biodiversity patterns and nonindigenous species (NIS) detection in an eDNA metabarcoding survey of four commercial ports. Overall, we captured sequences from 18 metazoan phyla with minimal differences in taxonomic coverage between 18 S and COI primer sets. While community dissimilarity patterns were consistent across primers and sampling effort, richness patterns were not, suggesting that richness estimates are extremely sensitive to primer choice and sampling effort. The survey detected 64 potential NIS, with COI identifying more known NIS from port checklists but 18 S identifying more operational taxonomic units shared between three or more ports that represent un-recorded potential NIS. Overall, we conclude that eDNA metabarcoding surveys can reveal global similarity patterns among ports across a broad array of taxa and can also detect potential NIS in these key habitats. However, richness estimates and species assignments require caution. Based on results of this study, we make several recommendations for port eDNA sampling design and suggest several areas for future research.


Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico/métodos , DNA/genética , DNA/isolamento & purificação , Meio Ambiente , Metagenômica/métodos , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , RNA Ribossômico 18S/genética
13.
PLoS Biol ; 16(4): e2005987, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29684017

RESUMO

A consistent determinant of the establishment success of alien species appears to be the number of individuals that are introduced to found a population (propagule pressure), yet variation in the form of this relationship has been largely unexplored. Here, we present the first quantitative systematic review of this form, using Bayesian meta-analytical methods. The relationship between propagule pressure and establishment success has been evaluated for a broad range of taxa and life histories, including invertebrates, herbaceous plants and long-lived trees, and terrestrial and aquatic vertebrates. We found a positive mean effect of propagule pressure on establishment success to be a feature of every hypothesis we tested. However, establishment success most critically depended on propagule pressures in the range of 10-100 individuals. Heterogeneity in effect size was associated primarily with different analytical approaches, with some evidence of larger effect sizes in animal rather than plant introductions. Conversely, no variation was accounted for in any analysis by the scale of study (field to global) or methodology (observational, experimental, or proxy) used. Our analyses reveal remarkable consistency in the form of the relationship between propagule pressure and alien population establishment success.


Assuntos
Distribuição Animal/fisiologia , Espécies Introduzidas/tendências , Modelos Estatísticos , Dispersão Vegetal/fisiologia , Animais , Teorema de Bayes , Ecossistema , Espécies Introduzidas/estatística & dados numéricos , Invertebrados/fisiologia , Plantas , Poaceae/fisiologia , Dinâmica Populacional , Tamanho da Amostra , Especificidade da Espécie , Árvores/fisiologia , Vertebrados/fisiologia
14.
Sci Rep ; 8(1): 1469, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29362389

RESUMO

Understanding the spatial distribution of human impacts on marine environments is necessary for maintaining healthy ecosystems and supporting 'blue economies'. Realistic assessments of impact must consider the cumulative impacts of multiple, coincident threats and the differing vulnerabilities of ecosystems to these threats. Expert knowledge is often used to assess impact in marine ecosystems because empirical data are lacking; however, this introduces uncertainty into the results. As part of a spatial cumulative impact assessment for Spencer Gulf, South Australia, we asked experts to estimate score ranges (best-case, most-likely and worst-case), which accounted for their uncertainty about the effect of 32 threats on eight ecosystems. Expert scores were combined with data on the spatial pattern and intensity of threats to generate cumulative impact maps based on each of the three scoring scenarios, as well as simulations and maps of uncertainty. We compared our method, which explicitly accounts for the experts' knowledge-based uncertainty, with other approaches and found that it provides smaller uncertainty bounds, leading to more constrained assessment results. Collecting these additional data on experts' knowledge-based uncertainty provides transparency and simplifies interpretation of the outputs from spatial cumulative impact assessments, facilitating their application for sustainable resource management and conservation.

15.
Proc Biol Sci ; 284(1860)2017 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-28794219

RESUMO

Self-replicating gene drives that can spread deleterious alleles through animal populations have been promoted as a much needed but controversial 'silver bullet' for controlling invasive alien species. Homing-based drives comprise an endonuclease and a guide RNA (gRNA) that are replicated during meiosis via homologous recombination. However, their efficacy for controlling wild populations is threatened by inherent polymorphic resistance and the creation of resistance alleles via non-homologous end-joining (NHEJ)-mediated DNA repair. We used stochastic individual-based models to identify realistic gene-drive strategies capable of eradicating vertebrate pest populations (mice, rats and rabbits) on islands. One popular strategy, a sex-reversing drive that converts heterozygous females into sterile males, failed to spread and required the ongoing deployment of gene-drive carriers to achieve eradication. Under alternative strategies, multiplexed gRNAs could overcome inherent polymorphic resistance and were required for eradication success even when the probability of NHEJ was low. Strategies causing homozygotic embryonic non-viability or homozygotic female sterility produced high probabilities of eradication and were robust to NHEJ-mediated deletion of the DNA sequence between multiplexed endonuclease recognition sites. The latter two strategies also purged the gene drive when eradication failed, therefore posing lower long-term risk should animals escape beyond target islands. Multiplexing gRNAs will be necessary if this technology is to be useful for insular extirpation attempts; however, precise knowledge of homing rates will be required to design low-risk gene drives with high probabilities of eradication success.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Espécies Introduzidas , Controle de Pragas/métodos , Animais , Feminino , Ilhas , Masculino , Camundongos , Coelhos , Ratos
16.
PLoS One ; 12(2): e0172851, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28235000

RESUMO

The international pet trade is a major source of emerging invasive vertebrate species. We used online resources as a novel source of information for accidental bird escapes, and we investigated the factors that influence the frequency and distribution of bird escapes at a continental scale. We collected information on over 5,000 pet birds reported to be missing on animal websites during the last 15 years in Australia. We investigated whether variables linked to pet ownership successfully predicted bird escapes, and we assessed the potential distribution of these escapes. Most of the reported birds were parrots (> 90%), thus, we analysed factors associated with the frequency of parrot escapes. We found that bird escapes in Australia are much more frequent than previously acknowledged. Bird escapes were reported more frequently within, or around, large Australian capital cities. Socio-economic factors, such as the average personal income level of the community, and the level of human modification to the environment were the best predictors of bird escapes. Cheaper parrot species, Australian natives, and parrot species regarded as peaceful or playful were the most frequently reported escapees. Accidental introductions have been overlooked as an important source of animal incursions. Information on bird escapes is available online in many higher income countries and, in Australia, this is particularly apparent for parrot species. We believe that online resources may provide useful tools for passive surveillance for non-native pet species. Online surveillance will be particularly relevant for species that are highly reported, such as parrots, and species that are either valuable or highly commensal.


Assuntos
Aves , Conservação dos Recursos Naturais , Animais de Estimação , Migração Animal , Animais , Animais Selvagens , Austrália , Cidades , Internet , Espécies Introduzidas , Papagaios , Dinâmica Populacional , Classe Social
17.
PLoS Biol ; 15(1): e2000942, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28081142

RESUMO

Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist there. However, global spatial and temporal variation in the drivers of alien introduction and species richness remain poorly understood. Here, we analyse an extensive new database of alien birds to explore what determines the global distribution of alien species richness for an entire taxonomic class. We demonstrate that the locations of origin and introduction of alien birds, and their identities, were initially driven largely by European (mainly British) colonialism. However, recent introductions are a wider phenomenon, involving more species and countries, and driven in part by increasing economic activity. We find that, globally, alien bird species richness is currently highest at midlatitudes and is strongly determined by anthropogenic effects, most notably the number of species introduced (i.e., "colonisation pressure"). Nevertheless, environmental drivers are also important, with native and alien species richness being strongly and consistently positively associated. Our results demonstrate that colonisation pressure is key to understanding alien species richness, show that areas of high native species richness are not resistant to colonisation by alien species at the global scale, and emphasise the likely ongoing threats to global environments from introductions of species.


Assuntos
Biodiversidade , Aves/fisiologia , Internacionalidade , Espécies Introduzidas , Animais , Produto Interno Bruto , Especificidade da Espécie , Fatores de Tempo
18.
PLoS One ; 11(12): e0168789, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27992568

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0161929.].

19.
PLoS One ; 11(10): e0161929, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27736884

RESUMO

Avian influenza viruses are able to persist in the environment, in-between the transmission of the virus among its natural hosts. Quantifying the environmental factors that affect the persistence of avian influenza virus is important for influencing our ability to predict future outbreaks and target surveillance and control methods. We conducted a systematic review and quantitative meta-analysis of the environmental factors that affect the decay of low pathogenic avian influenza virus (LPAIV) in water. Abiotic factors affecting the persistence of LPAIV have been investigated for nearly 40 years, yet published data was produced by only 26 quantitative studies. These studies have been conducted by a small number of principal authors (n = 17) and have investigated a narrow range of environmental conditions, all of which were based in laboratories with limited reflection of natural conditions. The use of quantitative meta-analytic techniques provided the opportunity to assess persistence across a greater range of conditions than each individual study can achieve, through the estimation of mean effect-sizes and relationships among multiple variables. Temperature was the most influential variable, for both the strength and magnitude of the effect-size. Moderator variables explained a large proportion of the heterogeneity among effect-sizes. Salinity and pH were important factors, although future work is required to broaden the range of abiotic factors examined, as well as including further diurnal variation and greater environmental realism generally. We were unable to extract a quantitative effect-size estimate for approximately half (50.4%) of the reported experimental outcomes and we strongly recommend a minimum set of quantitative reporting to be included in all studies, which will allow robust assimilation and analysis of future findings. In addition we suggest possible means of increasing the applicability of future studies to the natural environment, and evaluating the biological content of natural waterbodies.


Assuntos
Aves/virologia , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Microbiologia da Água , Animais , Surtos de Doenças , Salinidade , Temperatura Ambiente
20.
Ecohealth ; 13(2): 410-4, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27174429

RESUMO

Pigs carry receptors for both avian- and human-adapted influenza viruses and have previously been proposed as a mixing and amplification vessel for influenza. Until now, there has been no investigation of influenza A viruses within feral pigs in Australia. We collected samples from feral pigs in Ramsar listed wetlands of South Australia and demonstrated positive antibodies to influenza A viruses. We propose feral pigs, and their control programs, as an available resource for future surveillance for influenza A viruses.


Assuntos
Vírus da Influenza A/isolamento & purificação , Infecções por Orthomyxoviridae/veterinária , Sus scrofa , Animais , Austrália , Humanos , Influenza Humana , Suínos , Doenças dos Suínos , Zoonoses
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