The ‘grand scheme of things’: biological invasions, their detection, impacts and management

Editorial of Management of Biological Invasions: International Journal of Applied Research on Biological Invasions, Volume 5, Issues 3

A vision for global monitoring of biological invasions

Managing biological invasions relies on good global coverage of species distributions. Accurate information on alien species distributions, obtained from international policy and cross-border co-operation, is required to evaluate trans-boundary and trading partnership risks. However, a standardized approach for systematically monitoring alien species and tracking biological invasions is still lacking. This Perspective presents a vision for global observation and monitoring of biological invasions. We show how the architecture for tracking biological invasions is provided by a minimum information set of Essential Variables, global collaboration on data sharing and infrastructure, and strategic contributions by countries. We show how this novel, synthetic approach to an observation system for alien species provides a tangible and attainable solution to delivering the information needed to slow the rate of new incursions and reduce the impacts of invaders. We identify three Essential Variables for Invasion Monitoring; alien species occurrence, species alien status and alien species impact. We outline how delivery of this minimum information set by joint, complementary contributions from countries and global community initiatives is possible. Country contributions are made feasible using a modular approach where all countries are able to participate and strategically build their contributions to a global information set over time. The vision we outline will deliver wide-ranging benefits to countries and international efforts to slow the rate of biological invasions and minimize their environmental impacts. These benefits will accrue over time as global coverage and information on alien species increases

Integrated assessment of biological invasions

An assessment of the consequences of biological invasions and of the measures taken against must be at the base of each social decision in this field. Three forms of uncertainty can be distinguished that make such a decision difficult to take: (1) factual uncertainty, which encompasses not only risk, but also unknown probabilities of known consequences, and unknown consequences, (2) individual uncertainty, i.e. insecurity about the values to consider, and about the form how to consider them, and (3) social actor uncertainty, i.e. uncertainty about the social actors to consider and how to do it. This paper furnishes axiomatic reflections about the difficulties of assessments integrating these three uncertainties. Using this analytical separation, it restructures two main assessment techniques, and herewith shows the main differences between cost-benefit-analysis and multi-criteria decision aid in supporting public decisions about biological invasions. It is shown that the main difference between cost-benefit-analysis, the classical economic decision support, and multi-criteria decision analysis is less its mono- vs. multi-criteria approach, but its facility to be embedded in a social decision context. With multicriteria decision aid it is more facile to lay open the uncertainties in all three dimensions and to make them an explicit topic for public discourse. Therefore, it seems more suitable as an assessment method for biological invasions. --Biodiversity,Multi-criteria analysis,Uncertainty,Integrated Assessment,Biological Invasion,Cost-benefit analysis

The economics of biological invasions

Biological invasions are an economic problem. Invasions are typically the intended or unintended consequence of economic activity. They impose real costs on society, and the risk of invasion depends on human behaviour. Effective control of invasions depends on using the right economic instruments and developing the right institutions. The problem has two special features. The first is that the risks of invasions may be very low, but the potential costs are high. Since they are not reflected in market prices, they are typically ignored. The second is that the control of potentially invasive species is a public good of the "weakest link" variety. Both features indicate a precautionary approach. To deal with the first, I recommend the use of environmental assurance bonds to cover society against the risks of invasive species whilst providing importers with an incentive to research the consequences of their actions. To deal with the second I recommend the development of an institution similar to the Atlanta Centre for Disease Control to provide the information and technical advice required if governments are to act, and a central organisation (involving UNEP, UNDP and the World Bank) to strengthen eradication, control of mitigation campaigns in those countries least able to deal with invasive species.Resource /Energy Economics and Policy,

Economic evaluation of biological invasions: A survey

Invasive species are one of the main reasons for the loss of biodiversity. Therefore, national strategies are developed to deal with biological invasions. Economic evaluation as a tool of policy advice has to take into account three challenges: (1) reflecting ecological knowledge, which is characterised by high uncertainty, (2) taking into account the political framework shaped by the Convention on Biological Diversity (CBD), and (3) being methodologically sound, e.g. considering all types of values and avoiding general flaws. In this paper we survey and critically analyse economic studies on biological invasions. We test with an evaluation grid whether the studies meet the challenges. We analysed 23 studies generally and 10 in more detail in order to assess their suitability as a policy advice and their methodical quality. As a result we note three main gaps: (1) current studies mostly have methodological shortcomings compared to their theoretical basis; (2) they do not take into account the politically formulated needs of the CBD; and (3) they hardly reflect the high degree of uncertainty associated with biological invasions. --Biological invasions,economic evaluation,policy advice,Convention on Biological Diversity

Maritime Trade, Biological Invasions, and the Properties of Alternate Inspection Regimes

We analyze the problem of preventing biological invasions caused by ships transporting internationally traded goods between countries and continents. Specifically, we ask the following question: Should a port manager have a small number of inspectors inspect arriving ships less stringently or should this manager have a large number of inspectors inspect the same ships more stringently? We use a simple queuing-theoretic framework and show that if decreasing the economic cost of regulation is very important then it makes more sense for the port manager to choose the less stringent inspection regime. In contrast, if reducing the damage from biological invasions is more salient then the port manager ought to pick the more stringent inspection regime.

Evolutionary dynamics of tree invasions: complementing the unified framework for biological invasions

Evolutionary processes greatly impact the outcomes of biological invasions. An extensive body of research suggests that invasive populations often undergo phenotypic and ecological divergence from their native sources. Evolution also operates at different and distinct stages during the invasion process. Thus, it is important to incorporate evolutionary change into frameworks of biological invasions because it allows us to conceptualize how these processes may facilitate or hinder invasion success. Here, we review such processes, with an emphasis on tree invasions, and place them in the context of the unified framework for biological invasions. The processes and mechanisms described are pre-introduction evolutionary history, sampling effect, founder effect, genotype-by-environment interactions, admixture, hybridization, polyploidization, rapid evolution, epigenetics and second-genomes. For the last, we propose that co-evolved symbionts, both beneficial and harmful, which are closely physiologically associated with invasive species, contain critical genetic traits that affect the evolutionary dynamics of biological invasions. By understanding the mechanisms underlying invasion success, researchers will be better equipped to predict, understand and manage biological invasions

Modelling biological invasions: individual to population scales at interfaces

Extracting the population level behaviour of biological systems from that of the individual is critical in understanding dynamics across multiple scales and thus has been the subject of numerous investigations. Here, the influence of spatial heterogeneity in such contexts is explored for interfaces with a separation of the length scales characterising the individual and the interface, a situation that can arise in applications involving cellular modelling. As an illustrative example, we consider cell movement between white and grey matter in the brain which may be relevant in considering the invasive dynamics of glioma. We show that while one can safely neglect intrinsic noise, at least when considering glioma cell invasion, profound differences in population behaviours emerge in the presence of interfaces with only subtle alterations in the dynamics at the individual level. Transport driven by local cell sensing generates predictions of cell accumulations along interfaces where cell motility changes. This behaviour is not predicted with the commonly used Fickian diffusion transport model, but can be extracted from preliminary observations of specific cell lines in recent, novel, cryo-imaging. Consequently, these findings suggest a need to consider the impact of individual behaviour, spatial heterogeneity and especially interfaces in experimental and modelling frameworks of cellular dynamics, for instance in the characterisation of glioma cell motility

Biological Invasions: The Case of Soybean Aphid Infestation

Soybeans, the second highest cash crop following corn in the U.S., have come under attack by invasive species, the soybean aphid from the North and soybean rust from the South. We estimated the economic losses resulting from soybean aphid infestation by using a dynamic equilibrium model. Results indicate that, first, the reduction of soybean production resulting from soybean aphid infestation is largely absorbed by reducing soybean exports, due to the higher price elasticity of export demand compared to the domestic demand. Second, the economic losses to U.S. soybean producers would grow on average annually between $12.8 million and$23.4 million during the first five years of infestation. In the longer-run, soybean producers would suffer greater economic losses as the dispersion rate of infested soybean acreage with soybean aphids rises. However, the successful discovery of the soybean aphid gene (TF04048) Rag-1 (which confers resistance) does not at this time warrant soybean growers and policy-makers becoming too seriously alarmed. Even so, time is an important factor in the eventual control of the soybean aphid.Crop Production/Industries,

Capacity of countries to reduce biological invasions

The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-economic and environmental indices (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain country-level (1) established alien species (EAS) richness of eight taxonomic groups, and (2) proactive or reactive capacity to prevent and manage biological invasions and their impacts. These indices underpin many aspects of the invasion process, including the introduction, establishment, spread and management of alien species. They are also general enough to enable a global comparison across countries, and are therefore essential for defining future scenarios for biological invasions. Models including Trade, Governance, Lifestyle and Education, or a combination of these, best explained EAS richness across taxonomic groups and national proactive or reactive capacity. Historical (1996 or averaged over 1996–2015) levels of Governance and Trade better explained both EAS richness and the capacity of countries to manage invasions than more recent (2015) levels, revealing a historical legacy with important implications for the future of biological invasions. Using Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions, we identified four main clusters of countries in 2015. Most countries had an increase in Trade over the past 25 years, but trajectories were more geographically heterogeneous for Governance. Declines in levels of Governance are concerning as they may be responsible for larger levels of invasions in the future. By identifying the factors influencing EAS richness and the regions most susceptible to changes in these factors, our results provide novel insights to integrate biological invasions into scenarios of biodiversity change to better inform decision-making for policy and the management of biological invasions