Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape

An important factor that hinders the management of non‐native species is a general lack of information regarding the biogeography of non‐natives, and, in particular, their rates of turnover. Here, we address this research gap by analysing differences in temporal beta‐diversity (using both pairwise and multiple‐time dissimilarity metrics) between native and non‐native species, using a novel time‐series dataset of arthropods sampled in native forest fragments in the Azores. We use a null model approach to determine whether temporal beta‐diversity was due to deterministic processes or stochastic colonisation and extinction events, and linear modelling selection to assess the factors driving variation in temporal beta‐diversity between plots. In accordance with our predictions, we found that the temporal beta‐diversity was much greater for non‐native species than for native species, and the null model analyses indicated that the turnover of non‐native species was due to stochastic events. No predictor variables were found to explain the turnover of native or non‐native species. We attribute the greater turnover of non‐native species to source‐sink processes and the close proximity of anthropogenic habitats to the fragmented native forest plots sampled in our study. Thus, our findings point to ways in which the study of turnover can be adapted for future applications in habitat island systems. The implications of this for biodiversity conservation and management are significant. The high rate of stochastic turnover of non‐native species indicates that attempts to simply reduce the populations of non‐native species in situ within native habitats may not be successful. A more efficient management strategy would be to interrupt source‐sink dynamics by improving the harsh boundaries between native and adjacent anthropogenic habitats.Portuguese FCT‐NETBIOME – ISLANDBIODIV grant 0003/2011.info:eu-repo/semantics/publishedVersio

The UK risk assessment scheme for all non-native species

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere

Is the number of non-native species in the European Union saturating?

Background Non-native species can have significant negative impacts on the environment, economies, and amongst others, also human Non-native species can have significant negative impacts on the environment, economies, and human Non-native species can have significant negative impacts on the environment, economies, and human well-being, among other factors. Globalisation and economic incentives have substantially facilitated the growth in the numbers of newly recorded non-native species in the European Union. The European Union’s diversity in terms of political and socio-economic differences across member states may have contributed to the introduction of non-native species. Results Data reported in the Alien Species First Record Database, however, suggests a decreasing trend in the number of non-native species recorded over the past three decades. InvaCost, a database of non-native species with economic impacts, similarly shows increasing numbers of reported non-native species with costs until the 2010s, which were, however, followed by a plateauing and ultimately decline. Although the recent trends in non-native species reports may be affected by a lag time in reporting and data allocation as well as possibly a disparity in research efforts, their impacts persist, leading to a growing ecological but also economic burden. We further identified substantial spatial differences as western European member states generally reported higher numbers of non-native species and non-native species with monetary impacts. Conclusions Without improved actions, biological invasions and their associated impacts will continue to rise, degrading natural capital and hampering sustainable development and sustainability targets. Therefore, improved coordinated efforts across the European Union are necessary to improve reporting of non-native species and a centralized collation of data through accessible databases should be considered

European Non-native Species in Aquaculture Risk Analysis Scheme - a summary of assessment protocols and decision support tools for use of alien species in aquaculture

The European Non-native Species in Aquaculture Risk Analysis Scheme (ENSARS) was developed in response to European 'Council Regulation No. 708/2007 of 11 June 2007 concerning use of alien and locally absent species in aquaculture' to provide protocols for identifying and evaluating the potential risks of using non-native species in aquaculture. ENSARS is modular in structure and adapted from non-native species risk assessment schemes developed by the European and Mediterranean Plant Protection Organisation and for the UK. Seven of the eight ENSARS modules contain protocols for evaluating the risks of escape, introduction to and establishment in open waters, of any non-native aquatic organism being used (or associated with those used) in aquaculture, that is, transport pathways, rearing facilities, infectious agents, and the potential organism, ecosystem and socio-economic impacts. A concluding module is designed to summarise the risks and consider management options. During the assessments, each question requires the assessor to provide a response and confidence ranking for that response based on expert opinion. Each module can also be used individually, and each requires a specific form of expertise. Therefore, a multidisciplinary assessment team is recommended for its completion

Understanding the threats posed by non-native species: public vs. conservation managers.

Public perception is a key factor influencing current conservation policy. Therefore, it is important to determine the influence of the public, end-users and scientists on the prioritisation of conservation issues and the direct implications for policy makers. Here, we assessed public attitudes and the perception of conservation managers to five non-native species in the UK, with these supplemented by those of an ecosystem user, freshwater anglers. We found that threat perception was not influenced by the volume of scientific research or by the actual threats posed by the specific non-native species. Media interest also reflected public perception and vice versa. Anglers were most concerned with perceived threats to their recreational activities but their concerns did not correspond to the greatest demonstrated ecological threat. The perception of conservation managers was an amalgamation of public and angler opinions but was mismatched to quantified ecological risks of the species. As this suggests that invasive species management in the UK is vulnerable to a knowledge gap, researchers must consider the intrinsic characteristics of their study species to determine whether raising public perception will be effective. The case study of the topmouth gudgeon Pseudorasbora parva reveals that media pressure and political debate has greater capacity to ignite policy changes and impact studies on non-native species than scientific evidence alone

Harbouring Aliens: Ports as Habitats for Non-native Species

Non-native species are widely regarded as a significant environmental threat and have been associated with biodiversity loss, species extinctions and the altering of ecosystem services. Shipping is the largest transport vector for aquatic species worldwide and ports, being central to this industry, are considered potential ‘hotspots’ for non-native species introductions. Ports are often heavily industrialised areas which can hinder access and the use of standard survey methods. As such, our knowledge of non-native species within UK ports is poor. As the foundation for this research I developed two different settlement surveys designed specifically to overcome some of the obstacles associated with working within active port environments. Surveys were deployed across five ports in South Wales, UK. I detected 13 non-native species and described the wider fouling communities present within each studied port. Whole community structure and their succession varied highly between ports, with salinity being the primary driver of differences between port communities. Significant differences in the observed non-native species between ports, independent of geographic proximity, highlighted the need to monitor individual ports with a view to implementing bespoke, effective management strategies. Colonisation of different material substrates was quantified and revealed that whilst the community structure varied between material types, non-native species would readily colonise all studied materials. These findings have particular importance for the management of non-native species within ports and have been used to inform port biosecurity procedures within the studied region. The successful deployment of the tailored survey methods within active ports will encourage regular monitoring for non-native species within UK ports. This research also showed that collaborations between researchers and port authorities can be highly effective for both parties and may indeed be necessary if we are to successfully manage aquatic non-native species within the UK

Show me the numbers: what data currently exist for non‐native species in the USA?

Non‐native species continue to be introduced to the United States from other countries via trade and transportation, creating a growing need for early detection and rapid response to new invaders. It is therefore increasingly important to synthesize existing data on non‐native species abundance and distributions. However, no comprehensive analysis of existing data has been undertaken for non‐native species, and there have been few efforts to improve collaboration. We therefore conducted a survey to determine what datasets currently exist for non‐native species in the US from county, state, multi‐state region, national, and global scales. We identified 319 datasets and collected metadata for 79% of these. Through this study, we provide a better understanding of extant non‐native species datasets and identify data gaps (ie taxonomic, spatial, and temporal) to help guide future survey, research, and predictive modeling efforts

Advancing impact assessments of non-native species: strategies for strengthening the evidence-base

The numbers and impacts of non-native species (NNS) continue to grow. Multiple ranking protocols have been developed to identify and manage the most damaging species. However, existing protocols differ considerably in the type of impact they consider, the way evidence of impacts is included and scored, and in the way the precautionary principle is applied. These differences may lead to inconsistent impact assessments. Since these protocols are considered a main policy tool to promote mitigation efforts, such inconsistencies are undesirable, as they can affect our ability to reliably identify the most damaging NNS, and can erode public support for NNS management. Here we propose a broadly applicable framework for building a transparent NNS impact evidence base. First, we advise to separate the collection of evidence of impacts from the act of scoring the severity of these impacts. Second, we propose to map the collected evidence along a set of distinguishing criteria: where it is published, which methodological approach was used to obtain it, the relevance of the geographical area from which it originates, and the direction of the impact. This procedure produces a transparent and reproducible evidence base which can subsequently be used for different scoring protocols, and which should be made public. Finally, we argue that the precautionary principle should only be used at the risk management stage. Conditional upon the evidence presented in an impact assessment, decision-makers may use the precautionary principle for NNS management under scientific uncertainty regarding the likelihood and magnitude of NNS impacts. Our framework paves the way for an improved application of impact assessments protocols, reducing inconsistencies and ultimately enabling more effective NNS management

The Role of Tourism and Recreation in the Spread of Non-Native Species: A Systematic Review and Meta-Analysis

Managing the pathways by which non-native species are introduced and spread is considered the most effective way of preventing species invasions. Tourism and outdoor recreation involve the frequent congregation of people, vehicles and vessels from geographically diverse areas. They are therefore perceived to be major pathways for the movement of non-native species, and ones that will become increasingly important with the continued growth of these sectors. However, a global assessment of the relationship between tourism activities and the introduction of non-native species–particularly in freshwater and marine environments–is lacking. We conducted a systematic review and meta-analysis to determine the impact of tourism and outdoor recreation on non-native species in terrestrial, marine and freshwater environments. Our results provide quantitative evidence that the abundance and richness of non-native species are significantly higher in sites where tourist activities take place than in control sites. The pattern was consistent across terrestrial, freshwater and marine environments; across a variety of vectors (e.g. horses, hikers, yachts); and across a range of taxonomic groups. These results highlight the need for widespread biosecurity interventions to prevent the inadvertent introduction of invasive non-native species (INNS) as the tourism and outdoor recreation sectors grow