51 research outputs found

    Evaluation of the likelihood of establishing false codling moth (Thaumatotibia leucotreta) in Australia via the international cut flower market

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    Kenya and some other African countries are threatened by a serious pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), the false codling moth. The detection of T. leucotreta is quite difficult due to the cryptic nature of the larvae during transportation and is therefore a concern for Australia. This insect is a known pest of agriculturally important crops. Here, Maxent was used to assess the biosecurity threat of T. leucotreta to Australia. Habitat suitability and risk assessment of T. leucotreta in Australia were identified based on threatened areas under suitable climatic conditions and the presence of hosts in a given habitat. Modeling indicated that Australia is vulnerable to invasion and establishment by T. leucotreta in some states and territories, particularly areas of western and southern Australia. Within these locations, the risk is associated with specific cropping areas. As such, invasion and establishment by T. leucotreta may have serious implications for Australia’s agricultural and horticultural industries e.g., the fruit and vegetable industries. This study will be used to inform the government and industry of the threat posed by T. leucotreta imported via the cut flower industry. Targeted preventative measures and trade policy could be introduced to protect Australia from invasion by this pest

    Use of mixed-type data clustering algorithm for characterizing temporal and spatial distribution of biosecurity border detections of terrestrial non-indigenous species

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    Appropriate inspection protocols and mitigation strategies are a critical component of effective biosecurity measures, enabling implementation of sound management decisions. Statistical models to analyze biosecurity surveillance data are integral to this decision-making process. Our research focuses on analyzing border interception biosecurity data collected from a Class A Nature Reserve, Barrow Island, in Western Australia and the associated covariates describing both spatial and temporal interception patterns. A clustering analysis approach was adopted using a generalization of the popular k-means algorithm appropriate for mixed-type data. The analysis approach compared the efficiency of clustering using only the numerical data, then subsequently including covariates to the clustering. Based on numerical data only, three clusters gave an acceptable fit and provided information about the underlying data characteristics. Incorporation of covariates into the model suggested four distinct clusters dominated by physical location and type of detection. Clustering increases interpretability of complex models and is useful in data mining to highlight patterns to describe underlying processes in biosecurity and other research areas. Availability of more relevant data would greatly improve the model. Based on outcomes from our research we recommend broader use of cluster models in biosecurity data, with testing of these models on more datasets to validate the model choice and identify important explanatory variables

    Biosecurity risks posed by a large sea-going passenger vessel: Challenges of terrestrial arthropod species detection and eradication

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    Large sea-going passenger vessels can pose a high biosecurity risk. The risk posed by marine species is well documented, but rarely the risk posed by terrestrial arthropods. We conducted the longest running, most extensive monitoring program of terrestrial arthropods undertaken on board a passenger vessel. Surveillance was conducted over a 19-month period on a large passenger (cruise) vessel that originated in the Baltic Sea (Estonia). The vessel was used as an accommodation facility to house workers at Barrow Island (Australia) for 15 months, during which 73,061 terrestrial arthropods (222 species - four non-indigenous (NIS) to Australia) were collected and identified on board. Detection of Tribolium destructor Uytt., a high-risk NIS to Australia, triggered an eradication effort on the vessel. This effort totalled more than 13,700 human hours and included strict biosecurity protocols to ensure that this and other non-indigenous species (NIS) were not spread from the vessel to Barrow Island or mainland Australia. Our data demonstrate that despite the difficulties of biosecurity on large vessels, stringent protocols can stop NIS spreading from vessels, even where vessel-wide eradication is not possible. We highlight the difficulties associated with detecting and eradicating NIS on large vessels and provide the first detailed list of species that inhabit a vessel of this kind

    A united front against marine invaders: Developing a cost‐effective marine biosecurity surveillance partnership between government and industry

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    Successful detection of introduced marine pests (IMP) relies upon effective surveillance. However, the expedience of responding following IMP detection is often dependent upon the relationship between regulators and stakeholders. Effective detection of IMP in areas such as commercial ports requires a collaborative approach, as port environments can be highly complex both above and below the water. This complexity can encompass physical, logistical, safety and legislative issues. With this in mind, the aquatic pest biosecurity section within the Department of Primary Industries and Regional Development (DPIRD) developed the State‐Wide Array Surveillance Program (SWASP) in collaboration with Western Australian Port Authorities and port industry stakeholders. The SWASP is primarily based on passive settlement arrays for IMP detection. Arrays are deployed at strategic locations within Ports. Marine growth samples collected from the arrays are processed using Next‐Generation Sequencing (NGS) to identify the presence of IMP within a specific geographical location. Over 8 years, participation in SWASP has grown from 3 to 11 ports, spanning over 11,000 km, from the tropical north to temperate south of Western Australia. The programme has proven to be highly effective as a means of fostering stakeholder involvement and, importantly for IMP surveillance. The growth and success of SWASP has continued primarily because of the commitment and farsightedness of the ports involved. The regular presence of the biosecurity regulator as a partner in SWASP has provided a consistent face for biosecurity and fostered good stakeholder relationships, ensuring there is a reliable and effective ongoing marine surveillance programme for the state. Synthesis and applications. Through a united and collaborative approach to marine biosecurity surveillance, port authorities, industry and biosecurity regulators have developed the State‐Wide Array Surveillance Program (SWASP) and closed a major gap in biosecurity surveillance. The SWASP collaboration uses passive settlement arrays and molecular analyses to provide regular marine pest surveillance from the tropics to temperate regions of Western Australia. The continued commitment has embedded valuable relationships between stakeholder and regulator ensuring ongoing surveillance in marine biosecurity for the state. The Western Australian SWASP example has inspired other jurisdictions around Australia to develop similar collaborative approaches which will have far‐reaching marine biosecurity benefits

    Sea surface temperatures of the Leeuwin Current in the Capes region of Western Australia: Potential effects on the marine biota of shallow reefs

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    The Leeuwin and Capes Currents have been shown to influence marine assemblages along the W'estern Australian coast. In this study we examined potential relationships between the sea surface water temperature (SST), as a consequence of the Leeuwin and Capes Currents, and the distribution of fishes and algae. Data were collected from locations that spanned the temperate Capes coast (33°30' to 34°25'S). Fish assemblages were measured using diver operated stereo-video and stereo baited remote underwater video. Algae were harvested from quadrats. Mean SST at the most southerly region was 18.5°C while regions on the west coast of the Capes were generally one degree warmer. Seventy three species of fishes were recorded belonging to 36 families. Two species were classified as tropical and one species as sub-tropical (Cirrhilabrus temmincki, Plectorhinchus flauomaculatus and Choerodon mbescens respectively). Forty four percent of species from the Capes were classified as either tropical, subtropical or subtropical-temperate. The remainder were of temperate or widespread distributions. Two hundred and five species of algae were recorded belonging to 49 families. All species were regarded as temperate with the exception of the geniculate red alga, Rhodopeltis borealis. Eleven range extensions were recorded for algae: two were southward of the current known range (Champia compressa and Rhodopeltis borealis) and the remaining nine were northward or westward extensions. WTthin the 120 km of the Capes coast studied, regions with warmer waters did not have higher abundances of fishes of tropical, subtropical or subtropical-temperate origin than cooler waters. However, the most southerly region was different in terms of algal assemblage structure with water temperature the most influential of environmental variables, relative to exposure, substratum and depth. The large proportion of fish species with tropical, subtropical and particularly subtropical-temperate distributions recorded is consistent with other studies and may be due to the influence of the Leeuwin Current. The range extensions for algal species may be due to the effects of the Leeuwin and Capes Currents but may also be due to the paucity of algal collections from some parts of the Capes region. Other factors such as topographic complexity, depth and other habitat structure variables may also be influencing marine assemblages. The findings of the work support the notion that there is a large transition zone between biogeographic provinces within which the Capes region is positioned

    Vegetative and reproductive phenologies of four mangrove species from northern Australia

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    Mangrove communities in the tropical north of Australia are some of the most species rich in the world, yet surprisingly little is known of their reproductive and vegetative phenology. This study investigated the phenology of four mangrove species: Avicennia marina (Forsk.) Vierh., Ceriops australis (C.T. White) Ballment, T.J.Sm & Stoddart, Rhizophora stylosa Griff. and Sonneratia alba J. Smith, in Darwin Harbour over 24 months. Investigations included documenting the flowering and fruiting phenology, periods of leaf flush and leaf longevity. Flowering in these mangroves generally occurred during the dry season (June-October), with the exception of R. stylosa in which flowering occurred in the middle of the wet (December-February). Fruits and propagules were released in the dry and 'build up' periods (August-November), with the exception of A. marina, which released propagules in the middle of the wet season. Fruit and/or propagule maturation took less than 2 months in A. marina and S. alba, whereas in C. australis and R. stylosa maturation took 12 and 11 months, respectively. Timing of new leaf production generally coincided with the wet season, after the flowering and fruiting periods of each of the four species. Periods of leaf flush and leaf fall were often closely linked, and species with longer-lived leaves produced fewer leaves at each period of leaf flush. Maximum leaf longevity varied considerably among mangroves, ranging from 8 months in the lower canopy of S. alba to more than 24 months in C. australis. There was also large variability in leaf longevity among different regions of the canopy, with shade leaves generally living longer than sun leaves, and leaves in the upper canopy (3-7 m) longer than those in the lower regions (0-3 m)

    Floral abortion and pollination in four species of tropical mangroves from northern Australia

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    We assessed natural rates of floral abortion in four common mangrove species from northern Australia and subsequently manipulated pollination experimentally. Sonneratia alba J. Smith exhibited the highest rate of fruit set of the four species (23%), indicating this mangrove was best able to utilise the natural pollination opportunities provided. Fruit set in S. alba appeared, however, to be pollinator limited, as large increases in fruit set occurred after manual cross-pollination of flowers. Avicennia marina (Forsk.) Vierh. had the highest rate of natural pollination, but fruit set was lower (15%) and appeared to be impeded by resource limitations. Although a range of insects visited Ceriops australis (C.T. White) Ballment, T.J. Sm & Stoddart, the rate of fruit set was low (3%) and the capacity for flower fertilisation limited, despite evidence of autogamy in this species. There was an indication of both resource and pollinator limitation in C. australis. Rhizophora stylosa Griff. exhibited limited fruit set (0.5%), possibly due to limiting maternal resources and the lack of adaptation of flowers to either animal or wind pollination. Large increases in fruit set were recorded after manual cross-pollination of R. stylosa flowers. R. stylosa and C. australis, characterised by resource rich propagules with long periods of development, both aborted a large proportion of propagules during the fruit maturation process

    Commercial trials evaluating the novel use of ethyl formate for in-transit fumigation of shipping containers

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    The use of shipping containers for cargo transportation has the potential to transport insect pests from infested to non-infested areas. Therefore, fumigation is required as an appropriate biosecurity measure to exterminate these pests. In-transit fumigation trials were conducted in two 20 ft shipping containers during a two-day journey in both September and December 2017. Ethyl formate (90 g m−3) was purged with nitrogen (EF + N2) into the containers. Ethyl formate concentration inside containers and the surrounding environment were monitored at timed intervals throughout the journey. Fumigation achieved sufficient concentration × time (Ct) products in the containers during the journey, which can exterminate all stages of most common insect pests. The Ct products in-transit were greater than those in a shipping container being fumigated in a stationary position at a dose rate of 90 g m-³ for 24 hours exposure. Levels of EF in the environment between 1-15 m downwind from the containers and driver’s cabin were less than 0.5 ppm at each of the timed intervals, 200 times below 100 ppm of EF Threshold Limit Value (TLV). Our study indicates that in-transit EF + N2 technology has the potential to deliver cost savings in the fumigation process through reduction of the Labor cost, elimination of the time a container and cargo must remain stationary in a fumigation yard and a significant decrease in total supply chain time (between container packing and receival)

    It is all in the looks: a rapid field-based visual assessment tool for evaluating the spawning likelihood of the Asian green mussel, Perna viridis (Linnaeus, 1758)

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    10.3391/mbi.2018.9.2.03Management of Biological Invasions9291-9
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