We developed two risk models to investigate the movement of introduced marine species into High-value areas (HVAs), using Undaria pinnatifida invasions in New Zealand as a model system. This process focussed on the secondary transfer of Undaria into the HVAs, as it is already introduced to New Zealand. The first model was a qualitative, theoretical risk assessment based on expert opinion, and was used by management to re-assess the potential impacts of Undaria on values associated with a set of six, expert identified, HVAs. The risk re-assessment process identified that Undaria posed an extreme risk to a majority of values in all evaluated HVAs. Based on this outcome, a realised risk assessment model was developed and is described that uses quantitative vessel and propagule strength data to examine secondary transfers of Undaria into HVAs. The realised risk assessment is the next stage in the process of delineating the risk Undaria poses to New Zealand HVAs. The intent of this process was to provide salient, credible and legitimate information to decision-makers in a transparent manner because direct impact data is limited and uncertain. Both models presented are readily applicable to Undaria invasions in different regions and countries, with the original re-assessment model having been used by biosecurity managers.

In this review, we (i) describe smallmouth bass (Micropterus dolomieu Lacepède, 1802) invasions past, present, and future; (ii) summarize the impact that this species can have on native communities; and (iii) describe and discuss various options for control. M. dolomieu are invasive throughout much of the United States, southern portions of Canada, and in countries in Europe, Asia, and Africa. Historically, this species spread via stocking programs intended to improve sport fisheries. Currently, their spread is facilitated by anglers and global climate change. Models predict that M. dolomieu will continue to spread with consequences for native prey fish, sport fish, and food webs through predation, competition, and hybridization. Effective control methods are necessary to mitigate these impacts. Options for M. dolomieu control include biological control, chemical control, environmental manipulation, and physical removal. However, our review of the literature suggests that only a handful of the possible control options have been explored (usually in isolation and with limited success), and that there is a clear need for focused research and informed management. For example, our elasticity analysis of published M. dolomieu matrix population models suggests that M. dolomieu control will be most effective when it targets eggs, larvae, and juveniles. We recommend targeting these life stages by using nest failure as part of an adaptive and integrated pest management approaches that incorporate existing and emerging technologies. However, we also emphasize that M. dolomieu control, where necessary and possible, is more likely to take the form of suppression rather than permanent eradication. Therefore, we also recommend efforts to prevent M. dolomieu (re)introduction.

Due to the challenges of managing invasive species, new technologies to assist in monitoring for the early detection of early life stages of invasive species is critical for many regions of the world. Invasive tunicates have been causing challenges to the shellfish aquaculture industry in Atlantic Canada, with Ciona intestinalis causing the most significant challenges to date. While existing early detection systems for this species depend on morphological screening of preserved water samples or DNA based assay screening of fresh/preserved water samples, these methods are limited as they do not have the ability to evaluate the viability of propagules present, and they are also not able to distinguish between different life stages of C. intestinalis that may be present in water samples. These factors are important since non-viable propagules are not a risk to shellfish regions and unfertilized eggs have a different risk factor than viable free swimming larvae. It is most important for shellfish aquaculture growers to know when free swimming larvae life stages are present in the water so that they can appropriately time their mitigation treatments. This study successfully used RT-qPCR to screen temporally expressed genes for exclusively expressed mRNA transcripts at target life stages of C. intestinalis. In addition, this study identified mRNA transcripts that are quickly degraded post-mortem which makes them excellent candidate markers for larval viability assays. Based on the results of this study, HOX2 or TPM1 markers can be used in RT-qPCR assays to determine whether the C. intestinalis material present in a water samples is an egg or a larvae. Finally the TPM2 marker can be used to evaluate whether the larvae are viable or non-viable. Such an assay would be beneficial in screening water samples around mussel processing plant effluent outflows as well as water samples from ballast water, thereby reducing the potential further spread of the invasive species.

Invasive species are currently considered one of the most important threats to global biodiversity. Established invaders are difficult to eradicate and management requires biosecurity measures to prevent secondary spread. Corbicula fluminea (Müller, 1774; Asian clam) has a worldwide invasive distribution and, as an ecosystem engineer, can have dramatic impacts on recipient systems, displacing native species and altering trophic structure. This study tested the efficacy of biosecurity methods for cleansing angling equipment (such as nets and waders) and other gear used in freshwater that may harbour C. fluminea and contribute to their secondary spread. C. fluminea of varying size were treated either with Virkon® Aquatic, common household bleach or salt at a variety of concentrations for a range of immersion times. Virkon® emerged as the most effective of the three treatment types and achieved 93.3% mortality when used at 2% for 5 minutes. With the bleach trials, there was no significant effect of immersion time on clam mortality, but 10% bleach for 60 minutes induced an average mortality of 76.7%. Further, maximum mortality in saltwater was only 13.3% with 60 minutes immersion. There was no significant difference in mortality among clam sizes. Virkon® is, therefore, recommended as the most effective product for treating angling and other gear that could potentially harbour and spread C. fluminea. We also assessed the effect of ‘drying times’ post-treatment and this was demonstrated to have no significant effect on clam mortality. Virkon® again gave the highest mortality of the three treatments, with 68.9% mortality achieved at 2% for 10 minutes. Overall, Virkon® emerges as an effective biosecurity measure, but further research is required to attain 100% mortality. Bleach may be useful when Virkon® is not available, but salt is relatively ineffective.

The exoskeleton of gastropods provides a convenient surface for carrying marks, and in the interest of improving future marking methods our laboratory assessed the performance of an enamel paint. The endurance of the paint was also compared to other marking methods assessed in the past. We marked the shells of 30 adult Chinese mystery snails Bellamya chinensis and held them in an aquarium for 181 days. We observed no complete degradation of any enamel-paint mark during the 181 days. The enamel-paint mark was superior to a nail-polish mark, which lasted a median of 100 days. Enamel-paint marks also have a lower rate of loss (0.00 month-1 181 days) than plastic bee tags (0.01 month-1, 57 days), gouache paint (0.07 month-1, 18.5 days), or car body paint from studies found in scientific literature. Legibility of enamel-paint marks had a median lifetime of 102 days. The use of enamel paint on the shells of gastropods is a viable option for studies lasting up to 6 months. Furthermore, visits to a capture-mark-recapture site 1 year after application of enamel-paint marks on B. chinensis shells produced several individuals on which the enamel paint was still visible, although further testing is required to clarify durability over longer periods.

Piedmont granite rock outcrops in the southeastern United States support a plant community rich in endemic and rare plant species. The ecotones of the granite outcrop and Piedmont oak hickory forest communities are under increasing pressure from exotic invasion and the potential impacts of this invasion on the native plants in these communities are unclear. We conducted an experimental removal of invasive plant species at the ecotone of two granite rock outcrops and monitored species richness and plant occurrence along random belt transects in invaded, uninvaded, and removal plots for three years. These transects captured a representative sample of the plant community from the rock edge 20 m into the forest interior. Hemispherical photographs and soil samples were used to monitor changes in light availability and soil nutrients. Vegetation classes demonstrated spatial distribution patterns related to proximity to rock edge and depth of soil, but removal of invasive species had no apparent effect on percent cover or native plant richness. Sodium, calcium, and magnesium were all found to be significant predictors of invasive species occurrence and sodium and calcium were correlated with soil depth. This research effort suggests that the occurrence of invasive species are not significantly impacting overall species richness in the ecotone of outcrop plant communities, however changes to the species richness of this plant community in response to invasive species removal may take longer to detect.

Invasive species pose a critical risk to wildlife habitat, ecosystem processes, and agricultural productivity. This risk is exemplified by the spread of Yellowtuft (Alyssum murale and Alyssum corsicum), in Josephine County, Oregon. Both species have spread into protected botanical areas, which are home to a number of endemic and endangered species. ArcGIS 10 software suite, a comprehensive system used to collect, analyze and distribute geographic information, provided the platform for spatial analysis of infestation sites. The advanced statistical model, MaxEnt, was used to project the likely distribution and suitable habitat for Yellowtuft across 208,513 hectares of southern Oregon and northern California, and identify patterns of spread and habitat suitability. 12 environmental characteristics representing topography, climate, soil characteristics and vegetation cover were used to project distribution across the study area. Current infestations were not found to exclusively reside along spread pathways - roads and streams – or require serpentine soils to establish. The single most important variable related to habitat suitability was elevation, followed by slope, soil depth and vegetation cover class. The suitable map identifies 10,729 hectares as suitable habitat for both Alyssum species, with the vast majority residing within the Illinois River Valley. The final results were overlaid with the 2011 surveyed areas to identify areas that were of high suitability but not yet surveyed to identify survey gaps and possible areas to focus treatment effort for the 2012 and 2013 field season. The results were also overlaid with a prospective aerial survey flight plan to examine if the survey incorporates all areas of high suitability. With limited resources, and costly efforts like aerial surveying, species modeling and spatial analysis provided information that assisted managers to streamline efforts and identify areas of higher suitability that were not actively surveyed.

EASIN-Lit is an initiative of the Joint Research Centre of the European Commission, aiming to facilitate access to spatial data published in the literature through the EASIN (European Alien Species Information Network) portal. Currently, information from 227 publications has been included, covering geo-referenced records for 236 species (1655 single records) and country-level occurrences for 3105 species. Systematic and harmonized access to such kind of data, otherwise dispersed in scientific libraries and archives, can be crucial for alien species distribution modeling and the implementation of early warning systems.