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1.
Ecol Appl ; 33(8): e2913, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37615222

RESUMEN

Integrated pest management (IPM) leverages our understanding of ecological interactions to mitigate the impact of pest species on economically and/or ecologically important assets. It has primarily been applied in terrestrial settings (e.g., agriculture), but has rarely been attempted for marine ecosystems. The crown-of-thorns starfish (CoTS), Acanthaster spp., is a voracious coral predator throughout the Indo-Pacific where it undergoes large population increases (irruptions), termed outbreaks. During outbreaks CoTS act as a pest species and can result in substantial coral loss. Contemporary management of CoTS on the Great Barrier Reef (GBR) adopts facets of the IPM paradigm to manage these outbreaks through strategic use of direct manual control (culling) of individuals in response to ecologically based target thresholds. There has, however, been limited quantitative analysis of how to optimize the implementation of such thresholds. Here we use a multispecies modeling approach to assess the performance of alternative CoTS management scenarios for improving coral cover trajectories. The scenarios examined varied in terms of their ecological threshold target, the sensitivity of the threshold, and the level of management resourcing. Our approach illustrates how to quantify multidimensional trade-offs in resourcing constraints, concurrent CoTS and coral population dynamics, the stringency of target thresholds, and the geographical scale of management outcomes (number of sites). We found strategies with low target density thresholds for CoTS (≤0.03 CoTS min-1 ) could act as "Effort Sinks" and limit the number of sites that could be effectively controlled, particularly under CoTS population outbreaks. This was because a handful of sites took longer to control, which meant other sites were not controlled. Higher density thresholds (e.g., 0.04-0.08 CoTS min-1 ), tuned to levels of coral cover, diluted resources among sites but were more robust to resourcing constraints and pest population dynamics. Our study highlights trade-off decisions when using an IPM framework and informs the implementation of threshold-based strategies on the GBR.


Asunto(s)
Antozoos , Humanos , Animales , Arrecifes de Coral , Ecosistema , Estrellas de Mar/fisiología , Control de Plagas
2.
Sci Rep ; 13(1): 12512, 2023 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-37532795

RESUMEN

Reliable information on population size is fundamental to the management of threatened species. For wild species, mark-recapture methods are a cornerstone of abundance estimation. Here, we show the first application of the close-kin mark-recapture (CKMR) method to a terrestrial species of high conservation value; the Christmas Island flying-fox (CIFF). The CIFF is the island's last remaining native terrestrial mammal and was recently listed as critically endangered. CKMR is a powerful tool for estimating the demographic parameters central to CIFF management and circumvents the complications arising from the species' cryptic nature, mobility, and difficult-to-survey habitat. To this end, we used genetic data from 450 CIFFs captured between 2015 and 2019 to detect kin pairs. We implemented a novel CKMR model that estimates sex-specific abundance, trend, and mortality and accommodates observations from the kin-pair distribution of male reproductive skew and mate persistence. CKMR estimated CIFF total adult female abundance to be approximately 2050 individuals (95% CI (950, 4300)). We showed that on average only 23% of the adult male population contributed to annual reproduction and strong evidence for between-year mate fidelity, an observation not previously quantified for a Pteropus species in the wild. Critically, our population estimates provide the most robust understanding of the status of this critically endangered population, informing immediate and future conservation initiatives.


Asunto(s)
Quirópteros , Conservación de los Recursos Naturales , Humanos , Animales , Masculino , Femenino , Especies en Peligro de Extinción , Densidad de Población , Ecosistema , Mamíferos
3.
Evol Appl ; 16(4): 911-935, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37124084

RESUMEN

Effective management of protected species requires information on appropriate evolutionary and geographic population boundaries and knowledge of how the physical environment and life-history traits combine to shape the population structure and connectivity. Saltwater crocodiles (Crocodylus porosus) are the largest and most widely distributed of living crocodilians, extending from Sri Lanka to Southeast Asia and down to northern Australia. Given the long-distance movement capabilities reported for C. porosus, management units are hypothesised to be highly connected by migration. However, the magnitude, scale, and consistency of connection across managed populations are not fully understood. Here we used an efficient genotyping method that combines DArTseq and sequence capture to survey ≈ 3000 high-quality genome-wide single nucleotide polymorphisms from 1176 C. porosus sampled across nearly the entire range of the species in Queensland, Australia. We investigated historical and present-day connectivity patterns using fixation and diversity indices coupled with clustering methods and the spatial distribution of kin pairs. We inferred kinship using forward simulation coupled with a kinship estimation method that is robust to unspecified population structure. The results demonstrated that the C. porosus population has substantial genetic structure with six broad populations correlated with geographical location. The rate of gene flow was highly correlated with spatial distance, with greater differentiation along the east coast compared to the west. Kinship analyses revealed evidence of reproductive philopatry and limited dispersal, with approximately 90% of reported first and second-degree relatives showing a pairwise distance of <50 km between sampling locations. Given the limited dispersal, lack of suitable habitat, low densities of crocodiles and the high proportion of immature animals in the population, future management and conservation interventions should be considered at regional and state-wide scales.

4.
Sci Total Environ ; 841: 156699, 2022 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-35710009

RESUMEN

Urban-living wildlife can be exposed to metal contaminants dispersed into the environment through industrial, residential, and agricultural applications. Metal exposure carries lethal and sublethal consequences for animals; in particular, heavy metals (e.g. arsenic, lead, mercury) can damage organs and act as carcinogens. Many bat species reside and forage in human-modified habitats and could be exposed to contaminants in air, water, and food. We quantified metal concentrations in fur samples from three flying fox species (Pteropus fruit bats) captured at eight sites in eastern Australia. For subsets of bats, we assessed ectoparasite burden, haemoparasite infection, and viral infection, and performed white blood cell differential counts. We examined relationships among metal concentrations, environmental predictors (season, land use surrounding capture site), and individual predictors (species, sex, age, body condition, parasitism, neutrophil:lymphocyte ratio). As expected, bats captured at sites with greater human impact had higher metal loads. At one site with seasonal sampling, bats had higher metal concentrations in winter than in summer, possibly owing to changes in food availability and foraging. Relationships between ectoparasites and metal concentrations were mixed, suggesting multiple causal mechanisms. There was no association between overall metal load and neutrophil:lymphocyte ratio, but mercury concentrations were positively correlated with this ratio, which is associated with stress in other vertebrate taxa. Comparison of our findings to those of previous flying fox studies revealed potentially harmful levels of several metals; in particular, endangered spectacled flying foxes (P. conspicillatus) exhibited high concentrations of cadmium and lead. Because some bats harbor pathogens transmissible to humans and animals, future research should explore interactions between metal exposure, immunity, and infection to assess consequences for bat and human health.


Asunto(s)
Quirópteros , Mercurio , Animales , Australia , Metales , Estaciones del Año
5.
Mov Ecol ; 10(1): 19, 2022 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-35410304

RESUMEN

BACKGROUND: Animals are important vectors for the dispersal of a wide variety of plant species, and thus play a key role in maintaining the health and biodiversity of natural ecosystems. On oceanic islands, flying-foxes are often the only seed dispersers or pollinators. However, many flying-fox populations are currently in decline, particularly those of insular species, and this has consequences for the ecological services they provide. Knowledge of the drivers and the scale of flying-fox movements is important in determining the ecological roles that flying-foxes play on islands. This information is also useful for understanding the potential long-term consequences for forest dynamics resulting from population declines or extinction, and so can aid in the development of evidence-based ecological management strategies. To these ends, we examined the foraging movements, floral resource use, and social interactions of the Critically Endangered Christmas Island flying-fox (Pteropus natalis). METHODS: Utilization distributions, using movement-based kernel estimates (MBKE) were generated to determine nightly foraging movements of GPS-tracked P. natalis (n = 24). Generalized linear models (GLMs), linear mixed-effect models (LMMs), and Generalized linear mixed-effects model (GLMMs) were constructed to explain how intrinsic factors (body mass, skeletal size, and sex) affected the extent of foraging movements. In addition, we identified pollen collected from facial and body swabs of P. natalis (n = 216) to determine foraging resource use. Direct observations (n = 272) of foraging P. natalis enabled us to assess the various behaviors used to defend foraging resources. RESULTS: Larger P. natalis individuals spent more time foraging and less time traveling between foraging patches, traveled shorter nightly distances, and had smaller overall foraging ranges than smaller conspecifics. Additionally, larger individuals visited a lower diversity of floral resources. CONCLUSIONS: Our findings suggest that smaller P. natalis individuals are the primary vectors of long-distance dispersal of pollen and digested seeds in this species, providing a vital mechanism for maintaining the flow of plant genetic diversity across Christmas Island. Overall, our study highlights the need for more holistic research approaches that incorporate population demographics when assessing a species' ecological services.

6.
R Soc Open Sci ; 8(4): 201296, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-34007456

RESUMEN

On the iconic Great Barrier Reef (GBR), the cumulative impacts of tropical cyclones, marine heatwaves and regular outbreaks of coral-eating crown-of-thorns starfish (CoTS) have severely depleted coral cover. Climate change will further exacerbate this situation over the coming decades unless effective interventions are implemented. Evaluating the efficacy of alternative interventions in a complex system experiencing major cumulative impacts can only be achieved through a systems modelling approach. We have evaluated combinations of interventions using a coral reef meta-community model. The model consisted of a dynamic network of 3753 reefs supporting communities of corals and CoTS connected through ocean larval dispersal, and exposed to changing regimes of tropical cyclones, flood plumes, marine heatwaves and ocean acidification. Interventions included reducing flood plume impacts, expanding control of CoTS populations, stabilizing coral rubble, managing solar radiation and introducing heat-tolerant coral strains. Without intervention, all climate scenarios resulted in precipitous declines in GBR coral cover over the next 50 years. The most effective strategies in delaying decline were combinations that protected coral from both predation (CoTS control) and thermal stress (solar radiation management) deployed at large scale. Successful implementation could expand opportunities for climate action, natural adaptation and socioeconomic adjustment by at least one to two decades.

8.
Sci Rep ; 10(1): 12594, 2020 07 28.
Artículo en Inglés | MEDLINE | ID: mdl-32724152

RESUMEN

Population outbreaks of Crown-of-Thorns Starfish (COTS; Acanthaster spp.) are a major contributor to loss of hard coral throughout the Indo-Pacific. On Australia's Great Barrier Reef (GBR), management interventions have evolved over four COTS outbreaks to include: (1) manual COTS control, (2) Marine Protected Area (MPA) zoning, and, (3) water quality improvement. Here we evaluate the contribution of these three approaches to managing population outbreaks of COTS to minimize coral loss. Strategic manual control at sites reduced COTS numbers, including larger, more fecund and damaging individuals. Sustained reduction in COTS densities and improvements in hard coral cover at a site were achieved through repeated control visits. MPAs influenced initial COTS densities but only marginally influenced final hard coral cover following COTS control. Water quality improvement programs have achieved only marginal reductions in river nutrient loads delivered to the GBR and the study region. This, a subsequent COTS outbreak, and declining coral cover across the region suggest their contributions are negligible. These findings support manual control as the most direct, and only effective, means of reducing COTS densities and improving hard coral cover currently available at a site. We provide recommendations for improving control program effectiveness with application to supporting reef resilience across the Indo-Pacific.


Asunto(s)
Arrecifes de Coral , Estrellas de Mar/crecimiento & desarrollo , Animales , Australia , Conservación de los Recursos Naturales/métodos , Dinámica Poblacional , Conducta Predatoria , Estrellas de Mar/fisiología
9.
Sci Rep ; 10(1): 8184, 2020 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-32424321

RESUMEN

The corallivorous Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) has been linked with the widespread loss of scleractinian coral cover on Indo-Pacific reefs during periodic population outbreaks. Here, we re-examine CoTS consumption by coral reef fish species by using new DNA technologies to detect Pacific Crown-of-Thorns Starfish (Acanthaster cf. solaris) in fish faecal and gut content samples. CoTS DNA was detected in samples from 18 different coral reef fish species collected on reefs at various stages of CoTS outbreaks in the Great Barrier Reef Marine Park, nine of which had not been previously reported to feed on CoTS. A comprehensive set of negative and positive control samples confirmed that our collection, processing and analysis procedures were robust, although food web transfer of CoTS DNA cannot be ruled out for some fish species. Our results, combined with the (i) presence of CoTS spines in some samples, (ii) reported predation on CoTS gametes, larvae and settled individuals, and (iii) known diet information for fish species examined, strongly indicate that direct fish predation on CoTS may well be more common than is currently appreciated. We provide recommendations for specific management approaches to enhance predation on CoTS by coral reef fishes, and to support the mitigation of CoTS outbreaks and reverse declines in hard coral cover.


Asunto(s)
Código de Barras del ADN Taxonómico , Heces , Intestinos , Estrellas de Mar/clasificación , Estrellas de Mar/genética , Animales , Arrecifes de Coral , Conducta Predatoria
10.
Sci Rep ; 9(1): 10222, 2019 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-31308411

RESUMEN

Knowledge of species' population trends is crucial when planning for conservation and management; however, this information can be difficult to obtain for extremely mobile species such as flying-foxes (Pteropus spp.; Chiroptera, Pteropodidae). In mainland Australia, flying-foxes are of particular management concern due their involvement in human-wildlife conflict, and their role as vectors of zoonotic diseases; and two species, the grey-headed flying-fox (Pteropus poliocephalus) and the spectacled flying-fox (P. conspicillatus), are currently threatened with extinction. Here we demonstrate that archival weather radar data over a period of ten years can be used to monitor a large colony of grey-headed flying-foxes near Melbourne. We show that radar estimates of colony size closely match those derived from traditional counting methods. Moreover, we show that radar data can be used to determine the timing and departure direction of flying-foxes emerging from the roost. Finally, we show that radar observations of flying-foxes can be used to identify signals of important ecological events, such as mass flowering and extreme heat events, and can inform human activities, e.g. the safe operation of airports and windfarms. As such, radar represents an extremely promising tool for the conservation and management of vulnerable flying-fox populations and for managing human interactions with these ecologically-important mammals.


Asunto(s)
Quirópteros/clasificación , Demografía/métodos , Seguimiento de Parámetros Ecológicos/métodos , Animales , Australia/epidemiología , Radar , Tiempo (Meteorología) , Zoonosis/prevención & control
11.
Infect Genet Evol ; 75: 103978, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31352147

RESUMEN

Phylogenetic inference of Hepatocystis, a haemosporidian parasite of diverse primate and bat hosts, revealed that the parasites from Australasian Pteropus bat species form a distinct clade to all other Hepatocystis parasites from Africa and Asia. Here, we investigate the phylogenetic placement of Hepatocystis in the Australian bat Pteropus poliocephalus for the first time and examine parasite morphology and prevalence from selected points across its range. Hepatocystis infections were detected in low prevalences in P. poliocephalus in contrast to high numbers in P. alecto and P. scapulatus. The prevalence in P. poliocephalus varied across its distribution range with 15% in the central biogeographic areas (central Queensland and New South Wales) and 1% in the southern-most edge (South Australia) of its range. Sequencing of five genes revealed high genetic similarity in Hepatocystis of P. poliocephalus independent of sampling location. Phylogenetic analysis placed these parasites with Hepatocystis from other Pteropus species from Australia and Asia. While numerous haplotypes were identified among sequences from the Pteropus hosts, no patterns of host specificity were recovered within the Pteropus-specific parasite group.


Asunto(s)
Quirópteros/parasitología , Haemosporida/clasificación , Proteínas Protozoarias/genética , Análisis de Secuencia de ADN/métodos , Animales , Asia , Australia , Haemosporida/genética , Nueva Gales del Sur , Filogenia , Filogeografía , Queensland
12.
J Mammal ; 99(6): 1510-1521, 2018 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-30538341

RESUMEN

Flying foxes (family Pteropodidae) have distinct life histories given their size, characterized by longevity, low reproductive output, and long gestation. However, they tend to decouple the age at which sexual maturity is reached from the age at which they reach adult dimensions. We examined growth, maturation, and reproduction in the Critically Endangered Christmas Island flying fox (Pteropus natalis) to determine the timing of sex-specific life cycle events and patterns of growth. We estimated that juvenile growth in forearm length and body mass increased at a mean rate of 0.029 ± 0.005 mm/day and 0.33 ± 0.07 g/day for both males and females alike. Using these growth rates, we determined that the birth of pups occurs between December and March, with young becoming volant between June and August. The age at maturation for P. natalis is one of the oldest among all bat species. Juvenile males began to mature 15 months after birth and reached maturity 27 months after birth. Females reached maturity 24 months after birth at a significantly smaller body mass (3.6%) and forearm length (1.4%) than males. Significant sexual dimorphism and bimaturation was observed, with juvenile males being 1.5% and adult males being 1.9% larger on average than females for skeletal dimensions only. Growth and maturation are even slower in P. natalis than in the few other Pteropus species studied to date. The slow growth and delayed maturation of P. natalis imply slower potential population growth rates, further complicating the recovery of this Critically Endangered single-island endemic.

13.
Sci Rep ; 8(1): 9555, 2018 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-29934514

RESUMEN

In the Australian subtropics, flying-foxes (family Pteropididae) play a fundamental ecological role as forest pollinators. Flying-foxes are also reservoirs of the fatal zoonosis, Hendra virus. Understanding flying fox foraging ecology, particularly in agricultural areas during winter, is critical to determine their role in transmitting Hendra virus to horses and humans. We developed a spatiotemporal model of flying-fox foraging intensity based on foraging patterns of 37 grey-headed flying-foxes (Pteropus poliocephalus) using GPS tracking devices and boosted regression trees. We validated the model with independent population counts and summarized temporal patterns in terms of spatial resource concentration. We found that spatial resource concentration was highest in late-summer and lowest in winter, with lowest values in winter 2011, the same year an unprecedented cluster of spillover events occurred in Queensland and New South Wales. Spatial resource concentration was positively correlated with El Niño Southern Oscillation at 3-8 month time lags. Based on shared foraging traits with the primary reservoir of Hendra virus (Pteropus alecto), we used our results to develop hypotheses on how regional climatic history, eucalypt phenology, and foraging behaviour may contribute to the predominance of winter spillovers, and how these phenomena connote foraging habitat conservation as a public health intervention.


Asunto(s)
Conducta Animal , Quirópteros/virología , Ambiente , Virus Hendra/fisiología , Modelos Estadísticos , Análisis Espacio-Temporal , Animales
14.
Sci Rep ; 8(1): 4038, 2018 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-29511249

RESUMEN

Monitoring flying-foxes is challenging as their extreme mobility produces highly dynamic population processes, considerable logistic difficulty, and variability in estimated population size. We report on methods for inferring population trend for the population of the spectacled flying-fox (Pteropus conspicillatus) in Australia. Monthly monitoring is conducted at all known roost sites across the species' range in the Wet Tropics Region. The proportion of animals in camps varies seasonally and stochastic environmental events appear to be influential. We develop a state-space model that incorporates these processes and enables inference on total population trends and uses early warning analysis to identify the causes of population dynamics. The model suggests that population growth rate is stable in the absence of cyclones, however, cyclones appear to impact on both survival and reproduction. The population recovered after two cyclones but declined after a third. The modelling estimates a population decline over 15 years of c. 75% (mean r = - 0.12yr-1 and belief of negative trend is c. 83%) suggesting that conservation action is warranted. Our work shows that a state-space modelling approach is a significant improvement on inference from raw counts from surveys and demonstrates that this approach is a workable alternative to other methods.


Asunto(s)
Quirópteros/crecimiento & desarrollo , Filogeografía , Dinámica Poblacional , Animales , Australia , Modelos Estadísticos , Análisis Espacio-Temporal , Clima Tropical
15.
PLoS One ; 12(9): e0180805, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28877193

RESUMEN

The movement capacity of the crown-of-thorns starfishes (Acanthaster spp.) is a primary determinant of both their distribution and impact on coral assemblages. We quantified individual movement rates for the Pacific crown-of-thorns starfish (Acanthaster solaris) ranging in size from 75-480 mm total diameter, across three different substrates (sand, flat consolidated pavement, and coral rubble) on the northern Great Barrier Reef. The mean (±SE) rate of movement for smaller (<150 mm total diameter) A. solaris was 23.99 ± 1.02 cm/ min and 33.41 ± 1.49 cm/ min for individuals >350 mm total diameter. Mean (±SE) rates of movement varied with substrate type, being much higher on sand (36.53 ± 1.31 cm/ min) compared to consolidated pavement (28.04 ± 1.15 cm/ min) and slowest across coral rubble (17.25 ± 0.63 cm/ min). If average rates of movement measured here can be sustained, in combination with strong directionality, displacement distances of adult A. solaris could range from 250-520 m/ day, depending on the prevailing substrate. Sustained movement of A. solaris is, however, likely to be highly constrained by habitat heterogeneity, energetic constraints, resource availability, and diurnal patterns of activity, thereby limiting their capacity to move between reefs or habitats.


Asunto(s)
Tamaño Corporal , Movimiento , Estrellas de Mar/anatomía & histología , Estrellas de Mar/fisiología , Animales , Océano Pacífico
16.
Environ Toxicol Chem ; 36(1): 103-112, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27219023

RESUMEN

Most catchments discharging into the Great Barrier Reef lagoon have elevated loads of suspended sediment, nutrients, and pesticides, including photosystem II inhibiting herbicides, associated with upstream agricultural land use. To investigate potential impacts of declining water quality on fish physiology, RNA sequencing (RNASeq) was used to characterize and compare the hepatic transcriptomes of barramundi (Lates calcarifer) captured from 2 of these tropical river catchments in Queensland, Australia. The Daintree and Tully Rivers differ in upstream land uses, as well as sediment, nutrient, and pesticide loads, with the area of agricultural land use and contaminant loads lower in the Daintree. In fish collected from the Tully River, transcripts involved in fatty acid metabolism, amino acid metabolism, and citrate cycling were also more abundant, suggesting elevated circulating cortisol concentrations, whereas transcripts involved in immune responses were less abundant. Fish from the Tully also had an increased abundance of transcripts associated with xenobiotic metabolism. Previous laboratory-based studies observed similar patterns in fish and amphibians exposed to the agricultural herbicide atrazine. If these transcriptomic patterns are manifested at the whole organism level, the differences in water quality between the 2 rivers may alter fish growth and fitness. Environ Toxicol Chem 2017;36:103-112. © 2016 SETAC.


Asunto(s)
Monitoreo del Ambiente/métodos , Perciformes/genética , Plaguicidas/toxicidad , Ríos/química , Transcriptoma/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Agricultura , Animales , Perfilación de la Expresión Génica , Masculino , Plaguicidas/análisis , Queensland , Contaminantes Químicos del Agua/análisis
17.
J Appl Ecol ; 52(1): 59-68, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25678718

RESUMEN

Containment can be a viable strategy for managing invasive plants, but it is not always cheaper than eradication. In many cases, converting a failed eradication programme to a containment programme is not economically justified. Despite this, many contemporary invasive plant management strategies invoke containment as a fallback for failed eradication, often without detailing how containment would be implemented.We demonstrate a generalized analysis of the costs of eradication and containment, applicable to any plant invasion for which infestation size, dispersal distance, seed bank lifetime and the economic discount rate are specified. We estimate the costs of adapting eradication and containment in response to six types of breach and calculate under what conditions containment may provide a valid fallback to a breached eradication programme.We provide simple, general formulae and plots that can be applied to any invasion and show that containment will be cheaper than eradication only when the size of the occupied zone exceeds a multiple of the dispersal distance determined by seed bank longevity and the discount rate. Containment becomes proportionally cheaper than eradication for invaders with smaller dispersal distances, longer lived seed banks, or for larger discount rates.Both containment and eradication programmes are at risk of breach. Containment is less exposed to risk from reproduction in the 'occupied zone' and three types of breach that lead to a larger 'occupied zone', but more exposed to one type of breach that leads to a larger 'buffer zone'.For a well-specified eradication programme, only the three types of breach leading to reproduction in or just outside the buffer zone can justify falling back to containment, and only if the expected costs of eradication and containment were comparable before the breach.Synthesis and applications. Weed management plans must apply a consistent definition of containment and provide sufficient implementation detail to assess its feasibility. If the infestation extent, dispersal capacity, seed bank longevity and economic discount rate are specified, the general results presented here can be used to assess whether containment can outperform eradication, and under what conditions it would provide a valid fallback to a breached eradication programme.

18.
Sci Total Environ ; 534: 79-84, 2015 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-25669144

RESUMEN

The presence and movements of organisms both reflect and influence the distribution of ecological resources in space and time. The monitoring of animal movement by telemetry devices is being increasingly used to inform management of marine, freshwater and terrestrial ecosystems. Here, we brought together academics, and environmental managers to determine the extent of animal movement research in the Australasian region, and assess the opportunities and challenges in the sharing and reuse of these data. This working group was formed under the Australian Centre for Ecological Analysis and Synthesis (ACEAS), whose overall aim was to facilitate trans-organisational and transdisciplinary synthesis. We discovered that between 2000 and 2012 at least 501 peer-reviewed scientific papers were published that report animal location data collected by telemetry devices from within the Australasian region. Collectively, this involved the capture and electronic tagging of 12 656 animals. The majority of studies were undertaken to address specific management questions; rarely were these data used beyond their original intent. We estimate that approximately half (~500) of all animal telemetry projects undertaken remained unpublished, a similar proportion were not discoverable via online resources, and less than 8.8% of all animals tagged and tracked had their data stored in a discoverable and accessible manner. Animal telemetry data contain a wealth of information about how animals and species interact with each other and the landscapes they inhabit. These data are expensive and difficult to collect and can reduce survivorship of the tagged individuals, which implies an ethical obligation to make the data available to the scientific community. This is the first study to quantify the gap between telemetry devices placed on animals and findings/data published, and presents methods for improvement. Instigation of these strategies will enhance the cost-effectiveness of the research and maximise its impact on the management of natural resources.


Asunto(s)
Biodiversidad , Monitoreo del Ambiente/métodos , Telemetría , Animales , Australasia , Ecosistema , Sistemas de Información Geográfica
19.
Mar Environ Res ; 104: 51-61, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25617679

RESUMEN

The Great Barrier Reef (GBR) is chronically exposed to agricultural run-off containing pesticides, many of which are known endocrine disrupting chemicals (EDCs). Here, we measure mRNA transcript abundance of two EDC biomarkers in wild populations of barramundi (Lates calcarifer) and coral trout (Plectropomus leopardus and Plectropomus maculatus). Transcription levels of liver vitellogenin (vtg) differed significantly in both species amongst sites with different exposures to agricultural run-off; brain aromatase (cyp19a1b) revealed some differences for barramundi only. Exposure to run-off from sugarcane that contains pesticides is a likely pathway given (i) significant associations between barramundi vtg transcription levels, catchment sugarcane land use, and river pesticide concentrations, and (ii) consistency between patterns of coral trout vtg transcription levels and pesticide distribution in the GBR lagoon. Given the potential consequences of such exposure for reproductive fitness and population dynamics, these results are cause for concern for the sustainability of fisheries resources downstream from agricultural land uses.


Asunto(s)
Peces/genética , Regulación de la Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , Plaguicidas/toxicidad , Trucha/genética , Vitelogeninas/genética , Contaminantes Químicos del Agua/toxicidad , Animales , Encéfalo/efectos de los fármacos , Femenino , Explotaciones Pesqueras , Masculino , Ríos
20.
Biol Rev Camb Philos Soc ; 90(1): 31-59, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24618017

RESUMEN

Seed persistence is the survival of seeds in the environment once they have reached maturity. Seed persistence allows a species, population or genotype to survive long after the death of parent plants, thus distributing genetic diversity through time. The ability to predict seed persistence accurately is critical to inform long-term weed management and flora rehabilitation programs, as well as to allow a greater understanding of plant community dynamics. Indeed, each of the 420000 seed-bearing plant species has a unique set of seed characteristics that determine its propensity to develop a persistent soil seed bank. The duration of seed persistence varies among species and populations, and depends on the physical and physiological characteristics of seeds and how they are affected by the biotic and abiotic environment. An integrated understanding of the ecophysiological mechanisms of seed persistence is essential if we are to improve our ability to predict how long seeds can survive in soils, both now and under future climatic conditions. In this review we present an holistic overview of the seed, species, climate, soil, and other site factors that contribute mechanistically to seed persistence, incorporating physiological, biochemical and ecological perspectives. We focus on current knowledge of the seed and species traits that influence seed longevity under ex situ controlled storage conditions, and explore how this inherent longevity is moderated by changeable biotic and abiotic conditions in situ, both before and after seeds are dispersed. We argue that the persistence of a given seed population in any environment depends on its resistance to exiting the seed bank via germination or death, and on its exposure to environmental conditions that are conducive to those fates. By synthesising knowledge of how the environment affects seeds to determine when and how they leave the soil seed bank into a resistance-exposure model, we provide a new framework for developing experimental and modelling approaches to predict how long seeds will persist in a range of environments.


Asunto(s)
Ecosistema , Germinación/fisiología , Plantas/clasificación , Semillas/fisiología , Plantas/genética , Suelo
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