Article

Estimating the financial costs of freshwater invasive species in Great Britain: A standardized approach to invasive species costing

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Abstract

Both ecological and economic impacts factor into invasive alien species (IAS) management considerations; however, economic impacts are often difficult to assess, much less quantify. Studies frequently aggregate identified financial costs as a proxy for IAS economic impacts, but these aggregate figures are often generated in an ad hoc fashion. Such estimates typically sum disparate costs, which might vary with respect to precision, accuracy, and scope. A standardized approach for IAS costing would better enable the comparison of cost estimates between taxa and across studies by controlling for surveying and scaling inconsistencies. This study develops a simple, survey-based approach to generate economic cost estimates for non-native freshwater invasive species (FIS) in Great Britain. The approach scales an average cost for each species by a ratio of management effort, thereby estimating the actual, annual expenditures incurred by a variety of stakeholders. The Great Britain-wide cost of controlling FIS is estimated to be approximately £26.5 million year−1; however, the costs of control could total £43.5 million year−1 if management efforts were undertaken at all FIS infested locations. Cost estimates are highest for Canadian pondweed (Elodea canadensis), a particularly widespread species, and for the zebra mussel (Dreissena polymorpha), which adversely impacts both industrial water users and boaters. This assessment of the relative economic impacts between species provides policy-makers with a monetary basis for rank-ordering species’ economic impacts and prioritizing management efforts. In addition, the cost assessment approach developed in this study could serve as a model for IAS economic impact assessments elsewhere. KeywordsInvasive alien species–Nonindigenous species–Economic impacts–Environmental management–Zebra mussel

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... Other UK studies have focused on specific environments and cost types. For freshwater invasions in Great Britain, costs of controlling invasive species have been projected at £43.5 million per year in the case of management being undertaken at all invaded locations (Oreska and Aldridge 2011). That pioneering study also highlighted aquatic macrophytes and zebra mussels as two particularly expensive species for management. ...
... Contrastingly, there were comparatively few studies documenting economic impacts of aquatic and semi-aquatic invasions, despite the presence of multiple aquatic invaders that are recognised as a high management priority in the UK (e.g. Oreska and Aldridge 2011;Booy et al. 2020) and high global aquatic invasion costs (Cuthbert et al. 2021a). This trend might also reflect broader research biases within ecology towards terrestrial over aquatic environments (Menge et al. 2009;Cuthbert et al. 2021a) or perhaps re-flect that aquatic invasion costs are more difficult to be observed empirically and thus likely to be predicted (and therefore excluded from our data subset). ...
... Aquatic and semi-aquatic invaders were more likely to incur management costs than direct damage, but the converse was true for terrestrial species. A study by Oreska and Aldridge (2011) found that aquatic invaders cost Great Britain £26.5-£43.5 million per year; like our study, most costs were attributed to macrophytes and bivalves. This suggests that observed management cost totals for aquatic systems ($258.5 million since 1976; £200.9 million) in our study may be underestimated. ...
Article
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Although the high costs of invasion are frequently cited and are a key motivation for environmental management and policy, synthesised data on invasion costs are scarce. Here, we quantify and examine the monetary costs of biological invasions in the United Kingdom (UK) using a global synthesis of reported invasion costs. Invasive alien species have cost the UK economy between US$6.9 billion and $17.6 billion (£5.4 – £13.7 billion) in reported losses and expenses since 1976. Most costs were reported for the entire UK or Great Britain (97%); country-scale cost reporting for the UK's four constituent countries was scarce. Reports of animal invasions were the costliest ($4.7 billion), then plant ($1.3 billion) and fungal ($206.7 million) invasions. Reported damage costs (i.e. excluding management costs) were higher in terrestrial ($4.8 billion) than aquatic or semi-aquatic environments ($29.8 million), and primarily impacted agriculture ($4.2 billion). Invaders with earlier introduction years accrued significantly higher total invasion costs. Invasion costs have been increasing rapidly since 1976, and have cost the UK economy $157.1 million (£122.1 million) per annum, on average. Published information on specific economic costs included only 42 of 520 invaders reported in the UK and was generally available only for the most intensively studied taxa, with just four species contributing 90% of species-specific costs. Given that many of the invasive species lacking cost data are actively managed and have well-recognised impacts, this suggests that cost information is incomplete and that totals presented here are vast underestimates owing to knowledge gaps. Financial expenditure on managing invasions is a fraction (37%) of the costs incurred through damage from invaders; greater investments in UK invasive species research and management are, therefore, urgently required.
... There is a wide range of risk posed by the global aquarium trade nexus and in the context of northern Australia this includes risk to subsistence fishing by indigenous people, recreational fishing including for local community recreation and tourism purposes, biodiversity loss, human heath (liver flukes, mosquitos) and agricultural impacts. However, there are several reasons why relevant estimates of economic impacts of aquatic biosecurity are rarely available (Lovell et al. 2006, Oreska andAldridge 2011). To some extent the technical challenges and resources required to perform such valuations are stumbling blocks (Oreska and Aldridge 2011) and partly the complexity of responses by naïve ecosystems to alien species is unpredictable and requires resourcing for economic analyses to have a meaningful basis. ...
... However, there are several reasons why relevant estimates of economic impacts of aquatic biosecurity are rarely available (Lovell et al. 2006, Oreska andAldridge 2011). To some extent the technical challenges and resources required to perform such valuations are stumbling blocks (Oreska and Aldridge 2011) and partly the complexity of responses by naïve ecosystems to alien species is unpredictable and requires resourcing for economic analyses to have a meaningful basis. Economic analyses are also often associated with cases of single pest species, or industries that deal with one or few commodities, whereas the aquarium trade comprises a myriad of biota and products often each of small economic value but many of which with potential to have far reaching environmental impact (i.e. the global aquarium trade nexus). ...
... Estimation of the order of magnitude of economic costs of environmental management and loss of economic revenue including ecotourism impacts is required to justify spending on biosecurity (e.g. Lovell et al. 2006, Oreska andAldridge 2011) and this may be achieved by estimating biosecurity needs associated with individual invasive species (e.g. Oreska and Aldridge 2011). ...
Technical Report
The global aquarium trade nexus is the human-mediated connection of aquatic biota between biogeographically separate ecosystems as a function of the ornamental trade industry. It is arguably the greatest biosecurity threat to freshwater ecosystems. It is not just a potential source of single invasive species in isolation, rather it is a constant supplier of harmful and potentially harmful species and pathogens from evolutionarily distinct biogeographic waterways. Understanding and dealing with this continual threat from a biological, ecological, economic and societal (including cultural) perspective has major ramifications for the planet. The global aquarium trade nexus is especially relevant to those receiving tropical biogeographic provinces and sub-tropical provinces in northern Australia, where many unique aquatic ecosystems are currently devoid of alien species. On a certain level, the ornamental industry serves as a beneficial societal endeavour with multiple economic, human health and lifestyle values. The hyper-diverse tropical communities of biota from multiple continents, islands and oceans provide spectacular resources for recreation, as pets and exhibits, and trade. However, there are many examples whereby the transfer of these biotas has had catastrophic environmental consequences for receiving ecosystems, and the potential threat for further and continued incursions is high. Aesthetically pleasing fauna and flora, particularly fishes, invertebrates and plants, are transported on a global scale to wholesaler, retailer, private and public aquaria, and ornamental ponds. The global aquarium trade includes the legal, illegal and incidental transport of biota and biological agents including large-bodied species that are familiar to the public, and microscopic size material including diseases and pathogens which are often the working domain of a small subset of specialists (e.g. plankton biologists, microbiologists, pathologists, veterinarians). The global aquarium trade nexus also encompasses the overharvest of endemic species and impacts to receiving ecosystems. Most notably, the global aquarium trade nexus refers to the transport of substantial components of fauna and flora from one biogeographic province to another, creating challenges far beyond the more tangible single-species pest problems that are traditionally grappled with at a local scale and for that matter as single pest species issues from local through to international scales of biosecurity. The global trade comprises both marine and freshwater biota, with the freshwater trade and the receiving tropical freshwater ecosystems in northern Australia the focus of the current report. To summarise, global aquarium trade nexus refers to an extensive and complex human driven transport network for biosecurity risk that involves the transport of species, assemblages and essentially an entire spectrum of biota. Its global biosecurity risk and relevance to native northern Australian waterways is substantial and remarkably it has been unaddressed. The current scoping study provides for a preliminary understanding of the numerous existing and potential pathways for incursions from the aquarium trade into freshwater ecosystems in tropical Australia, encompassing the lands and waterways north of the Tropic of Capricorn. Climatic conditions including water temperature play a major role in sustaining species in tropical regions and therefore much of the biota from the tropics do not threaten temperate climates (e.g. Bomford et al. 2010). From an Australian perspective, where European settlement has been most intense in the temperate (southern) parts of the country, there are major ramifications for the global aquarium trade nexus in northern Australia as human developments unfold. A finding of this desktop project is the lack of consolidated information relevant to tropical Australia in terms of biotic incursion of even the better documented taxa (e.g. freshwater fishes) and a lack of information on most taxa in the aquarium trade (e.g. shrimps, molluscs, diseases in the wild). This is the consequence of the extent and scale of the aquatic biosecurity task as well as ad hoc biological 5 sampling, under-resourcing of ecological surveys, monitoring and reporting in the grey or published literature, all of which is compounded by the remoteness of much of tropical northern Australia. Major knowledge gaps exist in terms of: a) the knowledge of the social and biophysical processes and agents including institutional networks in tropical Australia in regard to the aquarium trade, b) unbiased survey data of propagule and colonisation pressure from the aquarium trade, and c) risks and composition of aquatic fauna particularly at the modified habitat level. In terms of the latter, ecological data, let alone unbiased and independent ecological data, is severely lacking in relation to farm dams, public dams and water transfer schemes across much of tropical Australia. This is pertinent to private and public management of land and water not the least because such dams have the capability of acting as footholds for propagule production and entry to catchments. Biosecurity is very much a human endeavour. It involves the management of biotic materials dispersed by human and non-human agents. At a fundamental level there are single species problems that become the focus of management. In contrast, the global aquarium trade represents a source of a myriad of such single species problems, not to mention their interactions. For instance, an aquarium plant can be a potentially invasive species while also acting as a host to snails and their embryos and associated parasites and pathogens. Not surprisingly, best practice in such ecologically and societally complex circumstances is likely to require multijurisdictional responses inclusive of governmental, societal and industry participation and practice. It is emphasised that the term industry is used here to refer to the aquarium trade (including internet trading of products and biota) and importantly extended further to industries that are not necessarily intuitively thought of being relevant to the aquarium industry. The latter includes major industry and recreational practices in northern Australia (e.g. agricultural practices including water storage and transfer, recreational angling sector, and the fly in fly out workforce more generally). There is also considerable informal trade of aquarium biota not yet well documented or understood. Using translational ecology principles to engage tropical communities of people is the key to ensuring that the general public is being made aware of the risks, is informed of best practice methods, and can be involved in aquatic biosecurity. By definition, translational ecology draws on a cross section of representation from local council, government, non-government organisations (NGOs) and community groups. Federal and state agencies, the Commonwealth Science and Industry Research Organisation (CSIRO), universities and NGO’s all have roles to play in this process, however, attention needs to be paid to local societal ownership and responsibility for aspects of the biosecurity process. Given two of the relevant states have administrative capitals (Perth, Western Australia (WA); Brisbane, Queensland (Qld)) well south of the tropical region and this presents real challenges for resourcing and informed decision making associated with biosecurity and biodiversity value, whereas, the Northern Territory has its capital positioned in the tropics.
... There is a wide range of risk posed by the global aquarium trade nexus and in the context of northern Australia this includes risk to subsistence fishing by indigenous people, recreational fishing including for local community recreation and tourism purposes, biodiversity loss, human heath (liver flukes, mosquitos) and agricultural impacts. However, there are several reasons why relevant estimates of economic impacts of aquatic biosecurity are rarely available (Lovell et al. 2006, Oreska andAldridge 2011). To some extent the technical challenges and resources required to perform such valuations are stumbling blocks (Oreska and Aldridge 2011) and partly the complexity of responses by naïve ecosystems to alien species is unpredictable and requires resourcing for economic analyses to have a meaningful basis. ...
... However, there are several reasons why relevant estimates of economic impacts of aquatic biosecurity are rarely available (Lovell et al. 2006, Oreska andAldridge 2011). To some extent the technical challenges and resources required to perform such valuations are stumbling blocks (Oreska and Aldridge 2011) and partly the complexity of responses by naïve ecosystems to alien species is unpredictable and requires resourcing for economic analyses to have a meaningful basis. Economic analyses are also often associated with cases of single pest species, or industries that deal with one or few commodities, whereas the aquarium trade comprises a myriad of biota and products often each of small economic value but many of which with potential to have far reaching environmental impact (i.e. the global aquarium trade nexus). ...
... Estimation of the order of magnitude of economic costs of environmental management and loss of economic revenue including ecotourism impacts is required to justify spending on biosecurity (e.g. Lovell et al. 2006, Oreska andAldridge 2011) and this may be achieved by estimating biosecurity needs associated with individual invasive species (e.g. Oreska and Aldridge 2011). ...
Technical Report
Full-text available
The current scoping study provides for a preliminary understanding of the numerous existing and potential pathways for incursions from the aquarium trade into freshwater ecosystems in tropical Australia, encompassing the lands and waterways north of the Tropic of Capricorn. A finding of this desktop project is the lack of consolidated nformation relevant to tropical Australia in terms of biotic incursion of even the better documented taxa (e.g. freshwater fishes) and a lack of information on most taxa in the aquarium trade (e.g. shrimps, molluscs, diseases in the wild). This is the consequence of the extent and scale of the aquatic biosecurity task as well as ad hoc biological sampling, under-resourcing of ecological surveys, monitoring and reporting in the grey or published literature, all of which is compounded by the remoteness of much of tropical northern Australia.
... Where reported, economic impacts associated with IAS are burgeoning (e.g., Pimentel et al. 2001;Oreska and Aldridge 2011;Hoffman and Boradhurst 2016;Bradshaw et al. 2016). Although these earlier studies provided awareness and powerful incentives to increase expenditure on the management of IAS, they all focused on particular regions, habitat types and taxonomic groups. ...
... Nevertheless, the underrepresentation of aquatic and semi-aquatic ecosystems in studies on biological invasions is not unique to India, as these ecosystems are less represented in ecological literature than terrestrial ecosystems (Menge et al. 2009). More specifically, in the context of IAS, aquatic ecosystems, and in particular marine ones, might be underrepresented as well because these invasions might be less perceptible or costs are challenging to measure, thus, more likely to be predicted than observed (Oreska and Aldridge 2011;Cuthbert et al. 2021b). ...
Article
Full-text available
Biological invasions are one of the top drivers of the ongoing biodiversity crisis. An underestimated consequence of invasions is the enormity of their economic impacts. Knowledge gaps regarding economic costs produced by invasive alien species (IAS) are pervasive, particularly for emerging economies such as India—the fastest growing economy worldwide. To investigate, highlight and bridge this gap, we synthesised data on the economic costs of IAS in India. Specifically, we examine how IAS costs are distributed spatially, environmentally, sectorally, taxonomically, temporally, and across introduction pathways; and discuss how Indian IAS costs vary with socioeconomic indicators. We found that IAS have cost the Indian economy between at least US$ 127.3 billion to 182.6 billion (Indian Rupees ₹ 8.3 trillion to 11.9 trillion) over 1960–2020, and these costs have increased with time. Despite these massive recorded costs, most were not assigned to specific regions, environments, sectors, cost types and causal IAS, and these knowledge gaps are more pronounced in India than in the rest of the world. When costs were specifically assigned, maximum costs were incurred in West, South and North India, by invasive alien insects in semi-aquatic ecosystems; they were incurred mainly by the public and social welfare sector, and were associated with damages and losses rather than management expenses. Our findings indicate that the reported economic costs grossly underestimate the actual costs, especially considering the expected costs given India’s population size, gross domestic product and high numbers of IAS without reported costs. This cost analysis improves our knowledge of the negative economic impacts of biological invasions in India and the burden they can represent for its development. We hope this study motivates policymakers to address socio-ecological issues in India and launch a national biological invasion research programme, especially since economic growth will be accompanied by greater impacts of global change.
... In Great Britain, direct management costs for freshwater INNS have been estimated at £26.0 million per year (Oreska and Aldridge 2011), of which at least £4.6 million are borne by the water industry (Williams et al., 2010). As these figures are only direct costs, and do not include direct damage to infrastructures and service losses resulting from infestations they are likely to be conservative. ...
... Those for Northern Ireland have been estimated at over £46.0 million (Kelly, 2014). For the UK, the direct market impacts of signal crayfish on angling have been estimated as £1.0 million and the annual control costs as £8.8 million, while for zebra mussels, market-based damages and control costs are estimated as £18.7 million (Oreska and Aldridge 2011;Williams et al., 2010). Also, it is expected that climate change will lead to more INNS and to those present expanding their range. ...
Technical Report
Full-text available
The CCRA is a comprehensive assessment of the risks to the UK from climate change, as required by Act of Parliament every 5 years (Climate Change Act)
... Where reported, economic impacts associated with IAS are burgeoning (e.g., Pimentel et al. 2001;Oreska and Aldridge 2011;Hoffman and Boradhurst 2016;Bradshaw et al. 2016). Although these earlier studies provided awareness and powerful incentives to increase expenditure on the management of IAS, they all focused on particular regions, habitat types and taxonomic groups. ...
... Nevertheless, the underrepresentation of aquatic and semi-aquatic ecosystems in studies on biological invasions is not unique to India, as these ecosystems are less represented in ecological literature than terrestrial ecosystems (Menge et al. 2009). More speci cally, in the context of IAS, aquatic ecosystems, and in particular marine ones, might be underrepresented as well because these invasions might be less perceptible or costs are challenging to measure, thus, more likely to be predicted than observed (Oreska and Aldridge 2011;Cuthbert et al. 2021). ...
Preprint
Full-text available
Biological invasions are one of the top drivers of the ongoing biodiversity crisis. An underestimated consequence of invasions is the enormity of their economic impacts. Knowledge gaps regarding economic costs produced by invasive alien species (IAS) are pervasive, particularly for emerging economies such as India — the fastest growing economy worldwide. To bridge this gap, we synthesised data on economic costs of IAS in India. Specifically, we examine how IAS costs are distributed spatially, environmentally, sectorally, taxonomically, temporally and across introduction pathways; and discuss globally how IAS costs vary with socioeconomic indicators. We found that IAS have cost the Indian economy between at least US$ 127.3 billion to 182.6 billion (Indian Rupees ₹ 8.3 trillion to 11.9 trillion) over 1960–2020, and these costs have increased with time. Most recorded costs were not assigned to specific regions, environments, sectors, cost types and causal IAS. When costs were specifically assigned, maximum costs were incurred in west, south and north India, by invasive alien insects in semi-aquatic ecosystems, incurred mainly by the public and social welfare sector, and were associated with damages and losses rather than management expenses. Our findings indicate that the reported economic costs grossly underestimate the actual costs, especially when considering the expected costs given India's population size and gross domestic product (GDP). This cost analysis improves our knowledge of the negative economic impacts associated with biological invasions in India and the burden they can represent for its development. We hope that this study motivates policymakers to address socio-ecological issues, especially since economic growth will be accompanied by greater impacts of global change.
... We did not employ valuation techniques to generate new data. Several estimates of the economic impact of IAS on Great Britain or the UK exist (Williamson, 2002;White and Harris, 2002;Pimentel et al., 2005;Oreska and Aldridge, 2010), but these mostly lack detail for sectors of the economy. We investigated the current annual cost of IAS to eleven sectors of the economies of England, Scotland and Wales. ...
... As with previous studies (e.g. Oreska and Aldridge, 2010), this study has shown the lack of knowledge of conservationists of the monetary value of ecosystems and the cost of biodiversity loss. Most of the respondents to our questionnaire were active in the biodiver- ...
... In Europe alone, it is estimated that more than ten thousand nonnative species have become invasive, with a total estimated monetary damage of 12 billion euros per year (EEA, 2012). 1 The impacts of invasive species on economic activities, as well as their impacts on ecosystems and native biodiversity, justify meaningful management efforts. However, budgets allocated to biological invasions management are limited and both the implementation costs and the benefits of management programs vary greatly (Scalera, 2010;Oreska and Aldridge, 2011;Hoffmann and Broadhurst, 2016). We are faced with an uncomfortable choice: which management strategies should we employ? ...
... These constraints are implicitly incorporated in our model framework as we only compare a feasible set of control strategies. 20 seeScalera (2010),Oreska and Aldridge (2011) andHoffmann and Broadhurst (2016) for reviews on management costs of biological invasions in Europe, in the UK and in Australia. ...
Article
Full-text available
Biological invasions entail massive biodiversity losses and tremendouseconomic impacts that justify significant management efforts. Because thefunds available to control biological invasions are limited, there is a need toidentify priority species. This paper first review current invasive species pri-oritization methods and explicitly highlights their pitfalls. We then constructa cost-benefit optimization framework that incorporates species utility, eco-logical value, distinctiveness, and species interactions. This framework offersthe theoretical foundations of a simple and operational method for the man-agement of invasive species under a limited budget constraint. It takes theform of an algorithm for the prioritization of multiple biological invasions.
... The spread of invasive species has been a major driver of biodiversity losses across the globe [6,7] and continue to put increasing pressures on biodiversity [8]. Additionally their introductions can result in threats to agricultural resources [9], alterations to hydrology [10], and economic impacts [11][12][13]. Haubrock et al. [14] note that invasive freshwater bivalves, in particular, have had substantial economic impacts globally with an estimated cost of $63.7 billion USD from 1980-2020. ...
Article
Full-text available
Although Corbicula fluminea has been one of the more prolific freshwater invasive species in the world, previous studies have suggested a low probability for overwinter survival in northern latitudes without an artificially created thermal refuge. The discovery of live C . fluminea in a central Minnesota lake absent any known thermal refuge in 2020 presented an opportunity to further evaluate the overwinter survival and population structure of C . fluminea at the presumed edge of their potential range. The population was monitored from December 2020 through September 2021 alongside water temperature to better understand at which temperatures C . fluminea survived and if the population structure suggested reproduction occurring in the lake. We documented live C . fluminea in temperatures as low as 0.3°C. Shell size of recovered individuals suggested multiple cohorts, and the appearance of a new cohort at the end of the study, indicating active reproduction in the lake and suggesting the population had likely been present in the lake for at least two winters by the conclusion of the study period. Our findings provide evidence of the survival below historically documented lower lethal temperature limits and suggests adaptations to modeling predicting suitable habitat, both present and in a changing climate, are necessary to better assess risk of invasion by this species.
... Invasive aquatic macrophytes often are recorded to be ecologically and economically damaging, for example, through increased flood risk, devaluation of property, the disruption of navigation, water abstraction, irrigation and recreational activities (Hussner et al., 2017;Oreska & Aldridge, 2011). Studies typically have focused on a small number of variables to explain invasion success, including the relationships between macrophytes and spatiotemporal patterns in water quality and the surrounding land use (Lougheed et al., 2001;Sass et al., 2010). ...
Article
Full-text available
1. Biological invasions, especially invasive alien aquatic plants, are a major and growing ecological and socioeconomic problem worldwide. Freshwater systems are particularly vulnerable to invasion, where impacts of invasive alien species can damage ecological structure and function. Identifying abiotic and biotic factors that mediate successful invasions is a management priority. Our aim was to determine the environmental correlates of Elodea nuttallii; a globally significant invasive aquatic species. 2. Elodea nuttallii presence/absence (occurrence), extent (patch area) and percentage cover (density) was visually assessed from a boat throughout Lough Erne (approximately 144 km 2), County Fermanagh, Northern Ireland during the active summer growth season (July-September). In addition, substrate type and zebra mussel Dreissena polymorpha occurrence was recorded. Fourteen water chemistry variables were collected monthly from 12 recording stations throughout the lake during the 9 years before the survey to spatially interpolate values and establish temporal trajectories in their change. Shoreline land use was derived from CORINE land cover maps. Environmental associations between E. nuttallii, substrate, D. polymorpha, water chemistry and land use were assessed. 3. Elodea nuttallii occurrence was positively associated with water conductivity, al-kalinity, suspended solids, phosphorus (both total and soluble) and chlorophyll-a concentrations, but negatively associated with pH and total oxidised nitrogen. E. nuttallii patch extent and proportional cover were positively associated, to varying degrees, with the presence of D. polymorpha, biological oxygen demand, water clarity and soft substrate, but negatively associated with urban development and ammonium. 4. Elodea nuttallii displayed high levels of phenotypic plasticity in response to environmental variation, allowing it to adapt to a wide range of conditions and potentially gain competitive advantage over native or other invasive macrophytes.
... Dreissenids in shallow area are predated heavily by waterbirds which contributes to an increase in numbers of overwintering waterbirds and nutrient flows from waterbirds' feeding areas to resting areas (Werner et al. 2005). Furthermore, dreissenid mussels are also a source of major economic impact due to biofouling of water pipes and other infrastructure (Marsden and Lansky 2000;Connelly et al. 2007), damage to recreational and commercial boats, and overall negative effects on fisheries (Oreska and Aldridge 2011;Rudstam et al. 2016). ...
Article
Full-text available
The dreissenids, quagga mussel Dreissena bugensis and zebra mussel D. polymorpha, are invasive freshwater mussels in Europe and North America. These species strongly impact aquatic ecosystems, such as the food web through their high abundance and filtration rate. They spread quickly within and between waterbodies, and have the ability to colonize various substrates and depths. The zebra mussel invaded and established in Swiss lakes in the 1960s, whereas the quagga mussel was not detected until 2014. We collected all available data from cantonal as well as local authorities and other institutions to describe the colonization pattern of quagga mussels in perialpine lakes north of the Alps. We also collected data regarding the distribution of larval stages of the mussels, the so-called veliger larvae. We observed that in lakes colonized by the quagga mussel, veligers are present the whole year round, whereas they are absent in winter in lakes with only zebra mussels. Additionally, we present detailed information about the invasion and colonization pattern of quagga mussels in Lake Constance. Quagga mussels colonized the lakeshore within a few years (~ 2016-2018), outcompeted zebra mussels, and have reached densities > 5000 ind. m-2 in the littoral zone, even at 80 m densities above 1000 ind. m-2 were found at some locations. At the end of the article, we discussed possibilities on how the spread of quagga mussels within and among northern perialpine lakes should be monitored and prevented in the future.
... The associated economic impact is even greater when considering that machine shutdown for maintenance and cleaning are always greater than 24 h (Flemming, 2002;Grohmann, 2008a;Pucherelli et al., 2018). Therefore, identifying the most suitable periods for machine shutdowns for maintenance and cleaning would allow the optimization of efforts and costs in the mid-and long-term, given that it would allow for maintenance efforts to be more effective and concentrated in time, which in turn would minimize control efforts in the intervening months (Grohmann, 2008c;Venkatesan & Murthy, 2008;Oreska & Aldridge, 2011;Frota et al., 2014;Boltovskoy et al., 2015b;Latombe et al., 2017). ...
Article
Full-text available
In this study, we investigate the main ecological interactions between fouling aquatic organisms (both invasive and native) present in the reservoir of the Governador José Richa hydroelectric plant, located in southern Brazil, and to identify the most suitable period for the interruption of machinery operation for cleaning and maintenance of the hydraulic systems of this plant. A total of 32 experimental plates were fixed to a metallic structure positioned close to the plant's water intake. Three species of invasive fouling were identified in our samples (Limnoperna fortunei [Mollusca], Cordylophora sp., and Hydra sp. [Cnidaria]) and six native taxa belonging to the phyla Protozoa, Ciliophora, Amoebozoa, and Arthropoda. Spring and summer were the seasons with the highest fouling rates, as well as densities of fouling organisms. The highest levels of diversity were recorded during the colder seasons. Several interactions between the organisms were identified, such as mutualism, commensalism, competition, epibiosis, cannibalism, and predation. The data obtained suggest that, from the biological point of view, the most suitable period for machine shutdown destined for the removal of biological fouling in the hydraulic systems of the studied plant is between the end of spring and the beginning of summer.
... A range of supporting methods are widely used to guide active management, but do not in themselves involve any form of intervention. These include informing the public and raising awareness (Eiswerth et al., 2011); early detection and monitoring (Trebitz et al., 2017); risk analysis, which includes risk assessment (Mandrak and Cudmore, 2015), risk management and risk communication (Verbrugge et al., 2014); contingency planning (Wittenberg and Cock, 2005); and analysis of costs (Oreska and Aldridge, 2011). All of these support active management and help ensure that it is well targeted, feasible and costeffective. ...
Chapter
a.Aim Outline of how the impact of non-native species can be defined and assessed, and how harmful non-native species can be managed across the different stages of the invasion process. b.Main concepts covered Impact as a concept in invasion biology; impact scales, levels and mechanisms; management categories c.Main methods covered EICAT and SEICAT schemes to assess the impacts of non-native species on biodiversity and socio-economics, respectively; framework for the management of non-native species d.Conclusions Efforts are needed to improve communication and understanding of researchers, policy-makers, practitioners and other stakeholders involved in the impact assessment and management of non-native species.
... Once alien species are introduced accidentally or intentionally may become invasive and can cause considerable harm to natural ecosystems, biodiversity, human health and economy (Pimentel et al. 2005, Oreska and Aldridge 2011). Nyman (1991 also highlighted that alien fish introduction may lead to irreversible changes in the aquatic ecosystems, habitat loss which could result in extinction of indigenous species. ...
Article
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The diverse germplasms pool already available in the vast and varied water resources of India has the potential to cater to the need of the fisheries and aquaculture sector, but the introduction of fish species for different purposes is still continuing. The exotic fishes introduced into India for different purposes covers nearly 13.6% of total fish diversity. Due to wider tolerance limits and generalist nature, some alien fish species have acclimatized to diverse eco-climatic conditions. Some of these introduced fishes are now established in the open water bodies including rivers, wetlands, and reservoirs and some others are in the process of establishment. Degraded open waters and wanton destruction of fishery resources in the rivers have resulted in the depletion of the sensitive fish species and the appearance of exotic fishes. The potential risk areas for the appearance of the alien species are mushrooming fish culture units in different parts of the country, porous boundaries, farming of alien fishes in flood-prone areas, the rapid expansion of aquaculture, and ornamental fish trade. Eradication of an introduced species is usually difficult or impossible once it is established in open water bodies. Therefore, there is an urgent need to regulate the import of alien fish species, based on their merit and likely impacts on open waters.
... we did not extrapolate or predict cost estimates independently here, and simply compiled reported costs). For example, potential costs may include estimated reductions in fisheries income because of an invasion (Scheibel et al., 2016), known local costs that are extrapolated to a larger system than the one they occur in (Oreska and Aldridge, 2011), and costs extrapolated over several years based on estimates from a shorter period (Leigh, 1998). ...
Article
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Invasive alien fishes have had pernicious ecological and economic impacts on both aquatic ecosystems and human societies. However, a comprehensive and collective assessment of their monetary costs is still lacking. In this study, we collected and reviewed reported data on the economic impacts of invasive alien fishes using InvaCost, the most comprehensive global database of invasion costs. We analysed how total (i.e. both observed and potential/predicted) and observed (i.e. empirically incurred only) costs of fish invasions are distributed geographically and temporally and assessed which socioeconomic sectors are most affected. Fish invasions have potentially caused the economic loss of at least US$37.08 billion (US2017 value) globally, from just 27 reported species. North America reported the highest costs (>85% of the total economic loss), followed by Europe, Oceania and Asia, with no costs yet reported from Africa or South America. Only 6.6% of the total reported costs were from invasive alien marine fish. The costs that were observed amounted to US$2.28 billion (6.1% of total costs), indicating that the costs of damage caused by invasive alien fishes are often extrapolated and/or difficult to quantify. Most of the observed costs were related to damage and resource losses (89%). Observed costs mainly affected public and social welfare (63%), with the remainder borne by fisheries, authorities and stakeholders through management actions, environmental, and mixed sectors. Total costs related to fish invasions have increased significantly over time, from <US$0.01 million/year in the 1960s to over US$1 billion/year in the 2000s, while observed costs have followed a similar trajectory. Despite the growing body of work on fish invasions, information on costs has been much less than expected, given the overall number of invasive alien fish species documented and the high costs of the few cases reported. Both invasions and their economic costs are increasing, exacerbating the need for improved cost reporting across socioeconomic sectors and geographic regions, for more effective invasive alien fish management.
... Invasive species demonstrate both ecological and economic impacts in both marine and freshwater ecosystems (Oreska & Aldridge, 2011;Birkan & Öndes, 2020). As a result of deliberate attempts to improve fisheries, this threat is further exacerbated by uncontrolled studies for aquaculture, or for biological control (Gaygusuz et al., 2015). ...
... Substantial variation in estimations of management and damage costs of IAS and the methodologies used, due to many sources being somewhat scattered and providing only anecdotal information at local, regional and national scales, have limited the estimation of IAS costs so far (e.g. Britton et al. 2010;Oreska and Aldridge 2011). Importantly, in several cases, data reporting the costs of IAS are often found in the grey literature (IUCN 2018), not easily accessible, sometimes not publicly available and not written in English (Angulo et al. 2021b). ...
Article
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Biological invasions continue to threaten the stability of ecosystems and societies that are dependent on their services. Whilst the ecological impacts of invasive alien species (IAS) have been widely reported in recent decades, there remains a paucity of information concerning their economic impacts. Europe has strong trade and transport links with the rest of the world, facilitating hundreds of IAS incursions, and largely centralised decision-making frameworks. The present study is the first comprehensive and detailed effort that quantifies the costs of IAS collectively across European countries and examines temporal trends in these data. In addition, the distributions of costs across countries, socioeconomic sectors and taxonomic groups are examined, as are socio-economic correlates of management and damage costs. Total costs of IAS in Europe summed to US$140.20 billion (or €116.61 billion) between 1960 and 2020, with the majority (60%) being damage-related and impacting multiple sectors. Costs were also geographically widespread but dominated by impacts in large western and central European countries, i.e. the UK, Spain, France, and Germany. Human population size, land area, GDP, and tourism were significant predictors of invasion costs, with management costs additionally predicted by numbers of introduced species, research effort and trade. Temporally, invasion costs have increased exponentially through time, with up to US$23.58 billion (€19.64 billion) in 2013, and US$139.56 billion (€116.24 billion) in impacts extrapolated in 2020. Importantly, although these costs are substantial, there remain knowledge gaps on several geographic and taxonomic scales, indicating that these costs are severely underestimated. We, thus, urge increased and improved cost reporting for economic impacts of IAS and coordinated international action to prevent further spread and mitigate impacts of IAS populations.
... These species can alter ecosystems that they colonise (Charles and Dukes 2008), for example by impeding ecosystem function and by reducing biodiversity (Powell et al. 2013). Also, as a result of colonisation, invasive alien species can impact on the local economy (Oreska and Aldridge 2011). Global trade and travel cause unprecedented propagule-pressure, the impacts of which are compounded by climate change. ...
Article
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Invasive alien species can negatively impact on newly colonised ecosystems. Thus, it is important to understand factors that facilitate invasiveness. Genetic diversity will enable a species to exploit a variety of environmental conditions. Yet, the process of dispersal to a new ecosystem will commonly create a genetic bottleneck and, hence, result in low diversity. Here we explored variability at genetic and morpho-physiological level of island of Ireland populations of alien, invasive Lemna minuta. A comparison of nine clones of L. minuta with nine clones of co-generic, native Lemna minor shows similar levels of genetic diversity across both species. Thus, the successful invasion of Ireland by L. minuta is associated with substantial, intraspecific diversity. It is hypothesised that increased biodiversity is due to repeated invasions from continental Europe, which occurred despite the geographic barriers separating the island from mainland Europe.
... Dikerogammarus villosus is recognised as a priority species for the UK water industry due to its negative impacts on threatened species, native biodiversity and UK anglers (Gallardo et al. 2012, Gallardo andAldridge 2020). Management costs associated with aquatic invasive NIS management in the UK are extensive at around £26 million a year in 2010, with £4.6 million spent by water companies alone (Oreska and Aldridge 2011). Given its restricted extent, eradication of D. villosus, defined as "the complete and permanent removal of all wild populations from a defined area by a time-limited campaign" (Bomford and O'Brien 1995) could be considered a possibility. ...
Article
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Aquatic invasions are a major ecological and socioeconomic concern. Management of invasive aquatic populations requires a robust understanding of the effectiveness and suitability of control methods. In this review, we consider multiple control options for the management of invasive aquatic amphipods, exploring their efficacy and application constraints. Technological opportunities (pheromone, RNAi, biotechnologies) and gaps in our understanding around control mechanisms are identified, with the aim to improve management success of this order. Within this review, the UK invasion of the killer shrimp, Dikerogammarus villosus (Sowinsky, 1894) is used as a case study of the best explored example of invasive amphipod control. This species has had a range of ecological, physiological, pathological, and experimental research conducted upon it, which is highlighted from a management perspective. This same data, where available, has been synthesised for 46 other invasive amphipods, to probe for weaknesses that future management methods can exploit and be developed around. Successful management examples for invasive amphipod species remain rare. A lack of currently available tested options severely limits the possibility for amphipod management, post establishment. For future management to be successful, further work is needed to develop targeted and specific control methods, which ideally, are cost effective, have no/little associated ecological impacts, and can be broadly applied in closed and open water systems. Our synthesis presents opportunities for the further, informed development of control systems for invasive amphipods.
... (ii)Implementation: referring to whether the cost estimate was actually realised in the invaded habitat (observed) or whether it was extrapolated (potential). For example, potential costs can include estimated reductions in shery income (Scheibel et al., 2016), known local costs that are extrapolated to a larger system in which they occur (Oreska and Aldridge, 2011), and costs extrapolated over multiple years based on estimates from a shorter period (Leigh, 1998); ...
Preprint
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Invasive alien fishes have caused pernicious ecological impacts on aquatic ecosystems. However, there has not been a global appraisal of associated economic impacts. Here, we compiled reported economic impacts of invasive alien fishes using the most comprehensive global database of invasion costs (InvaCost). We analyze how fish invasion costs are distributed geographically and temporally, as well as which socioeconomic sectors are most impacted. Fish invasions have caused the economic loss of at least US$32.8 billion globally (2017 value), from only 26 reported species (of 128 known invasive alien fish species). North America had the highest costs (> 99%), followed by Europe and Asia, with no costs reported in Africa, Oceania nor South America. Very few costs from invasive fish in the marine realm were reported (0.1%). Most costs are related to resource damages and losses (97%), with relatively little spent on management; mainly impacting the fisheries sector (93%). However, when only considering empirically observed costs (without predictions), most costs were incurred by authorities and stakeholders through management, indicating that damage costs from invasive fishes are often extrapolated and/or difficult to quantify. Fish invasion costs increase markedly over time, from US$0.57 billion/year in the 1980s to US$1 billion/year in the 2000s. Fish invasions have been relatively well studied; however, economic costs have been lower than expected based on overall numbers of alien species. Accordingly, although costs are increasing, improved reporting is required to better understand how fish invasion costs are distributed across time, space and economic sectors.
... However, studies of economic aspects of IAS have been limited to certain taxonomic groups (Bradshaw et al., 2016), communities, or regions (Pimentel et al., 2000;2005;Kettunen et al., 2009;Cuthbert et al., 2021;Haubrock et al., 2021). In particular, costs of aquatic IAS are generally less well understood than costs of terrestrial IAS, despite some estimates indicating high costs (Lovell et al., 2006;Aldridge and Oreska, 2011). Comprehensive and systematically-assembled data on the costs of aquatic IAS would greatly help planning and prioritisation for their management, in the context of limited resources (McGeoch et al., 2015). ...
Article
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Much research effort has been invested in understanding ecological impacts of invasive alien species (IAS) across ecosystems and taxonomic groups, but empirical studies about economic effects lack synthesis. Using a comprehensive global database, we determine patterns and trends in economic costs of aquatic IAS by examining: (i) the distribution of these costs across taxa, geographic regions and cost types; (ii) the temporal dynamics of global costs; and (iii) knowledge gaps, especially compared to terrestrial IAS. Based on the costs recorded from the existing literature, the global cost of aquatic IAS conservatively summed to US$345 billion, with the majority attributed to invertebrates (62%), followed by vertebrates (28%), then plants (6%). The largest costs were reported in North America (48%) and Asia (13%), and were principally a result of resource damages (74%); only 6% of recorded costs were from management. The magnitude and number of reported costs were highest in the United States of America and for semi-aquatic taxa. Many countries and known aquatic alien species had no reported costs, especially in Africa and Asia. Accordingly, a network analysis revealed limited connectivity among countries, indicating disparate cost reporting. Aquatic IAS costs have increased in recent decades by several orders of magnitude, reaching at least US$23 billion in 2020. Costs are likely considerably underrepresented compared to terrestrial IAS; only 5% of reported costs were from aquatic species, despite 26% of known invaders being aquatic. Additionally, only 1% of aquatic invasion costs were from marine species. Costs of aquatic IAS are thus substantial, but likely underreported. Costs have increased over time and are expected to continue rising with future invasions. We urge increased and improved cost reporting by managers, practitioners and researchers to reduce knowledge gaps. Few costs are proactive investments; increased management spending is urgently needed to prevent and limit current and future aquatic IAS damages
... Thus, our study shows that in lake-outlet streams dense populations of unionid mussels can reduce the numbers of D. polymorpha to no-impact levels over the time-scale of decades, and it provides evidence for a long-term biotic resistance of a natural native community. As invasion of D. polymorpha has devastating ecological and economic effects (Higgins and Vander Zanden, 2010;Oreska and Aldridge, 2011;Strayer and Malcom, 2018;Ożgo et al., 2020), our finding underscores the importance of functional lake-outlet streams for the self-sustaining integrity of freshwater ecosystems. ...
Article
Securing adequate supply of high-quality water is of increasing global importance and relies in large part on ecosystem services provided by freshwater biota. Unionid mussels are important keystone species and habitat engineers that shape freshwater ecosystems through water filtration, nutrient cycling and provision of habitats; their rapid global declines result in dramatic losses of ecosystem functions. Maintenance and enhancement of the services they provide depend on the identification of their crucial habitats. Following theoretical assumptions, this study analyses the importance of lake-stream transition zones for unionid mussels, based on data collected in 1984 and 2019 from an undisturbed stream flowing through five consecutive lakes. Mussel distribution matched the distribution of host fish and was strongly influenced by lakes: densities were highest near lake outlets, reaching 290 ind. m⁻² (14.7 kg m⁻²) in 2019, and declined with downstream distance following a negative power function. This pattern was spatially consistent and sustained over time. All six unionid species native to north-central Europe were present, but common species (Anodonta anatina, Unio pictorum, U. tumidus) contributed about 80% of individuals and were responsible for most of the ecosystem services provided by unionid mussels. Estimated 1.9 x 10⁶ mussel individuals inhabiting 3.2 km of stream length filtered a water volume equivalent to the total stream discharge approximately 2.5 times daily. Aggregations of spent shells, up to 17 kg m⁻², accumulated downstream of lakes, forming extensive shell and mussel beds, providing habitats and contributing shell hash that improved stream-bed conditions. Globally invasive Dreissena polymorpha was present at low densities and did not spread or increase in abundance, indicating a long-term biotic resistance of the natural native community. Our study underscores the importance of undisturbed lake outlets, longitudinal connectivity of riverine ecosystems, and of common mussel species in maintaining freshwater ecosystem functionality and provision of vital services.
... The zebra mussel (Dreissena polymorpha) is one of the most damaging invasive bivalves due to its wide niche, rapid population growth and negative impacts on the economy (Lowe et al. 2000). For example, in Great Britain £5 million are lost each year due to pipe fouling and damage to water infrastructures, while in North America $800,000 are spent yearly in each power plant infested by zebra mussels (Oreska and Aldridge 2011) which poses a significant biosecurity risk and a safety hazard (Meyerson and Reaser 2003). ...
Article
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Invasive bivalves can cause widespread ecological damage, but eradication has proved difficult. Identifying the pathways of dispersal is crucial to implementing more effective biocontainment measures. We examined the distribution of the highly invasive zebra mussel (Dreissena polymorpha) in Great Britain through Species Distribution Modelling to determine the drivers of distribution and generated suitability maps to predict future dispersal. Distance to boat ramps was the most important predictor of zebra mussel establishment, accounting for 27% of variation in occurrence. Probability of occurrence was highest within 3 km upstream of boat ramps, probably due to boating activity and the impounded waters typically associated with boat ramps. Our results highlight the need for implementing stringent control measures around boat ramps, and demonstrate the value of spatially modelling species distribution to create risk maps for targeting monitoring efforts at those locations most vulnerable to invasion.
... Sites of cargo importation such as ports are often colonised by shipping stowaways, as is the case with the European yellow-tailed scorpion (Euscorpius flavicaudis) in England (Kent) (Wanless, 1977). Some stowaway species such as the zebra mussel (Dreissena polymorpha) have both ecological and financial impacts, with costs incurred for their removal from water pipes and treatment works (Oreska & Aldridge, 2011). Whilst it is unlikely that stowaway reptiles and amphibians from the tropics will become established in Britain, those from temperate regions may have a greater chance of success. ...
... Accordingly, there is an urgent requirement to enhance public knowledge of IAS issues and relevant national and international IAS policy. Traditionally, conventional media have facilitated the dissemination of knowledge to the general public (Nisbet and Scheufele 2009). In recent years, however, online resources in the form of network-based databases have become an increasingly popular method of IAS information sharing and as a mechanism to bolster community-based environmental monitoring, especially concerning the cataloguing of species occurrence, distribution and impact records (Gatto et al., 2013). ...
Article
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Since 2016, the European Union (EU) has required Member States to prevent, control and eradicate selected invasive alien species (IAS) designated as Species of Union Concern. To improve these conservation efforts, online information systems are used to convey IAS information to the wider public, often as a means to bolster community-based environmental monitoring. Despite this, both the conformity and quality of information presented amongst online databases remain poorly understood. Here, we assess the harmonisation and educational potential of four major IAS databases (i.e., conformity of information and information quality, respectively): CABI, EASIN, GISD and NOBANIS. All databases were interrogated for information concerning 49 IAS of Union Concern. For each species, information presented within the evaluated databases was scored in relation to several key topics: morphological identification; EU distribution; detrimental impacts; control options ; and the use of source material citations. Overall, scores differed significantly among databases and thus lacked harmonisation, whereby CABI ranked significantly highest based on the combined scores for all topics. In addition, CABI ranked highest for the individual topics of species identification, impacts, control options, and for the use of citations. EASIN ranked highest for species distribution data. NOBANIS consistently ranked as the lowest scoring database across all topics. For each topic, the highest scoring databases achieved scores indicative of detailed or highly detailed information, which suggests a high educational potential for the information portrayed. Nevertheless, the extent of harmo-nisation and quality of information presented amongst online databases should be improved. This is especially pertinent if online databases are to contribute to public participatory monitoring initiatives for IAS detection.
... They may threaten human health by providing habitats for mosquitoes (O'Meara et al., 2003;Chandra et al., 2006). They also hamper recreational activities and disrupt agricultural production, causing great economic losses (Oreska and Aldridge, 2010;Rumlerova et al., 2016;Keller et al., 2018;Tanveer et al., 2018). Alien aquatic plants often compete for space, nutrients, and sediment fertilities with native macrophytes, thus hindering their reestablishment and decreasing diversity (Michelan et al., 2018;Silveira et al., 2018). ...
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I am glad to announce that the special issue “Multiple Roles of Alien Plants in Aquatic Ecosystems: from Processes to Modelling” of Frontiers in Plant Science is now available and freely accessible. A warm thank goes to my co-editors Lorenzo Lastrucci, Giuseppe Brundu and Andreas Hussner that helped me to manage this "editorial enterprise". Thanks a lot to all the Authors and Reviewers that made it possible.
... Potential measures that intervene in the spread of IAAPs at different stages of the invasion process are proposed ( Figure 1). As ongoing management incurs high costs (Oreska & Aldridge, 2011;Hussner et al., 2017) and prevention is generally more desirable (Vander Zanden et al., 2010;Caplat & Coutts, 2011), special emphasis is placed on preventing IAAPs from further spread within stream ecosystems and overland dispersal to isolated water bodies. The containment of detected infestations of IAAPs characterized by high fragment dispersal capacities (e.g. ...
Thesis
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Aquatic plant invasions pose a major threat to the biodiversity and functionality of freshwater ecosystems and harm human well-being and the economy. Most invasive alien aquatic plants predominantly reproduce through vegetative means in their introduced range, with unspecialized plant fragments being considered as the most important propagules. However, there is still a lack of knowledge about the species-specific dispersal capacity by plant fragments and the underlying dynamics in streams. According to the new EU Regulation 1143/2014 on the prevention and management of the introduction and spread of invasive alien species, information on a species’ reproduction and its spread patterns is mandatory. Thus, in order to comply with the EU Regulation, laboratory and field studies in lowland streams were conducted to assess the fragment dispersal capacity of native and invasive alien aquatic plants based on four key traits, comprising (i) fragmentation rate, (ii) drift distance, (iii) desiccation resistance relevant for overland dispersal to isolated waters and (iv) the regeneration and colonization potential of fragments. The findings of this thesis emphasize that fragment dispersal capacity is a major driving force behind the successful and rapid spread of many aquatic plant invaders worldwide. While the dispersal and invasion success of submerged species such as Myriophyllum spicatum, Potamogeton crispus, Elodea canadensis, Elodea nuttallii and Hydrilla verticillata can largely be attributed to a high fragment dispersal capacity, fragment dispersal seems to play only a minor role for the invasiveness of Lagarosiphon major and Myriophyllum heterophyllum. However, it was documented that fragment dispersal is strongly controlled by the hydrological and hydraulic stream properties and generally enhanced in streams characterized by high discharge and turbulent flow conditions. The spread of invasive alien aquatic plants therefore deserves particular attention in larger streams, as long as the degree of flow disturbance does not prevent the establishment and persistence of aquatic plants.
... Freshwater ecosystems are increasingly invaded by alien species introduced accidentally or deliberately (Dudgeon et al. 2006;Ricciardi 2006;Seebens et al. 2017). Once established, alien species can impact biodiversity and alter key ecosystem functions such as productivity, nutrient cycling and hydrology (Dudgeon et al. 2006;Oreska and Aldridge 2011;Piria et al. 2017;Crane et al. 2020). For example, invasive macrophytes can form dense monotypic stands that alter physical habitat and biotic (vegetation, macroinvertebrates and fish) communities, as well as the interactions within and between these communities (Dibble et al. 1996). ...
Article
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In aquatic systems, invasive submerged macrophytes considerably alter the structure and functioning of communities, thus potentially compromising ecosystem services. The prolific spread of invasive macrophytes is often aided by vegetative fragment propagation, yet the contributions of various commonly occurring invertebrates to such fragmentation are often unquantified. In the present study, we examine fragmentary spread of invasive macrophytes by a group of shredder-herbivores, larval caddisflies. Through novel application of the comparative functional response (FR; resource use as a function of density) approach to the native case-building species Limnephilus lunatus, we compared utilisation of non-native waterweeds Elodea canadensis and E. nuttallii in mono-and polycultures. Furthermore, we quantified de-cased and cased caddisfly-induced fragment production and length changes among non-native E. canadensis, E. nuttallii, Crassula helmsii and La-garosiphon major under two different plant orienta-tions: horizontal (floating) versus vertical (upright) growth forms. Larval caddisflies exhibited Type II (hyperbolic) FRs towards both Elodea species, and utilised each plant at similar rates when plants were provided separately. When plant species were presented in combination horizontally, E. canadensis was significantly less utilised compared to E. nuttallii, Kate Crane and Ross N. Cuthbert have contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.().,-volV) (01234567 89().,-volV) corroborating observations in the field. De-cased larvae produced new plant fragments for all four aquatic macrophytes, whereas cased larvae fragmented plants significantly less. Elodea nuttalii and C. helmsii were fragmented the most overall. Crassula helmsii was utilised to the greatest extent when plants were horizontally orientated, and Elodea species when vertically orientated. This study identifies and quantifies a mechanism from a novel species group that may contribute to the spread of invasive macrophytes in aquatic systems. Whilst exploititative interactions are thought to impede invasion success, here we demonstrate how resource utilisation by a resident species may exacerbate propagule pressure from an invasive species.
... Direct management costs for freshwater IAS in Great Britain have been estimated at £26 million each year (Oreska and Aldridge, 2011), of which at least £4.6 million are borne by the water industry (Williams et al., 2010). These cost estimates are conservative and do not include direct damage to infrastructures and service losses resulting from infestations. ...
Article
The expansion of Invasive Alien Species (IAS) is a growing concern to the UK water industry because of their diverse impacts on water quality, infrastructure and eradication costs. New regulations reinforcing the industry's responsibilities beyond operational costs, coupled with continued range expansion and establishment of new IAS will increase damages. To tackle IAS effectively, the water industry requires reliable information about which species pose the greatest risk to operations and which areas are most vulnerable to invasion. Here we assess potential biosecurity threats for the 24 water companies in the UK using well-established modelling research techniques such as risk assessment and distribution modelling. Using a consensus approach with environmental managers and water companies, we identified 11 IAS of concern for the UK water industry, including five plants, three crustaceans, two molluscs and one fish. These invaders pose important hazards in terms of water quality, flood protection, human health, integrity of infrastructures, recreational and aesthetic values, amongst others. We used distribution models to predict their potential expansion under current and future 2050 climate scenarios within each of the 24 water companies in the UK. Water companies in the South East of England (Cambridge Water, Anglian Water, Affinity Water and Thames Water) are under the highest risk of invasional meltdown from multiple IAS, both now and under future scenarios. The quagga mussel poses the most serious risk of immediate spread and may exacerbate the impacts of the widespread zebra mussel for the water industry. The information generated in this study can support the prioritization of species and regions at risk, so that funds for prevention and eradication of invasions are well allocated. Ultimately, this study demonstrates that scientific risk assessments, usually restricted to the academic and public sectors, can be extremely useful to guide decision-making by the private sector.
... The continued spread of invasive species across the globe is contributing to biodiversity loss in many ecosystems (Meyerson et al. 2019). As a consequence, invasive species confer substantial economic cost due to the necessity of constant management and mitigation protocols in order to reduce their vast potential ecological effects (Pimental et al. 2005;Oreska and Aldridge 2011;Meyerson et al. 2019). The burden of this makes management somewhat prohibitive, especially within developing countries. ...
Article
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Predicting and understanding the impact of biological invaders is a global ecological imperative. Progress has been made through the application of phenomenological analysis via comparative functional response analysis. However, little is known about the mechanisms which drive high-magnitude functional responses of invasive species, especially when compared to trophically analogous natives. Largemouth bass Micropterus salmoides is a freshwater invasive species evaluated as a more efficient predator, with a higher-magnitude functional response, compared to a native analogue, the Cape kurper Sandelia capensis. In order to determine what traits drive this difference we quantified handling time behaviours (detection time, catch time, processing time) of both predator species and prey/predator size ratio, and employ an ecomorphological approach to determine whether largemouth bass is a more specialised predator than Cape kurper. There was no difference in detection time between the species, but largemouth bass were significantly and on average five times faster at catching prey than Cape kurper. Both species’ processing time was positively related to prey size, but Cape kurper was on average 4.5 times faster than largemouth bass. Ecomorphological data indicate that largemouth bass was the more specialised pursuit hunter for fish, whereas Cape kurper was better at ambush hunting. This suggests that the ecological impact of largemouth bass may be exacerbated in areas where there is habitat simplification which can lead to the extirpation of local small-bodied fish. In addition, there may be non-consumptive detrimental effects on trophically analogous natives through competitive exclusion.
... In recent years, an increasing effort to study public attitudes toward non-native species have been observed, but most of the studies employed either quantitative (Andreu, Vilà, & Hulme, 2009;Bremner & Park, 2007;García-Llorente, Martín-López, González, Alcorlo, & Montes, 2008) or economic (Marshall, Friedel, van Klinken, & Grice, 2011;Oreska & Aldridge, 2011) approaches. Moreover, studies on perception of non-native species have been largely animal-oriented (Aguirre-Muñoz et al., 2011;Cerri, Ferretti, & Tricarico, 2016;Fleming & Bateman, 2016;Kapitza, Zimmermann, Martín-López, & von Wehrden, 2019;Schüttler, Rozzi, & Jax, 2011). ...
Article
Humans are the main drivers of the introduction, establishment and spread of non-native species worldwide but they have traditionally been excluded from management. Nowadays, the social component of non-native species is increasingly considered. In this paper, we investigated understanding, perceptions and attitudes towards management of non-native herbaceous plant species on Navarino, a remote Chilean sub-Antarctic island. Overall, our study showed a general understanding of the non-native species concept among the interviewees but revealed a lack of consciousness regarding non-native plants species in the local context. Interestingly, our study also revealed many positive values associated with non-native plants species on Navarino, particularly the esthetic value. Whilst some non-native plants were strictly associated with positive values, such as common daisy (Bellis perennis) and white clover (Trifolium repens), most species were associated with conflicting values. As a key result, our study lastly showed that most interviewees were indifferent about the management of the non-native herbaceous plant species. We, therefore, suggest (i) increasing the awareness of stakeholders with respect to non-native plants, (ii) incorporating stakeholder’s values into future management decisions and (iii) considering the strategic location of Navarino Island as a potential stepping stone for the dispersion of non-native plants species towards the Antarctic.
... Alien species associated with introductions and climateassociated range shifts present major ecological and economical concerns worldwide (Cheung et al. 2009;Simberloff et al. 2013). The "ecosystem services" perspective, which evaluates alien species in monetary terms (Vilà et al. 2010), often highlights the high economic costs of alien establishment in the invaded ecosystem (Oreska and Aldridge 2011). These costs have been associated with the introduction of pests (El-Sayed et al. 2009), damage to infrastructure (Connelly et al. 2007), and health risks (Medlock et al. 2012). ...
Article
Alien species may be a valuable resource for marine fisheries, yet their contribution to the catch might be balanced by negative effects on indigenous species. In this study, we explored a unique high-resolution time series of catch data from a highly invaded ecosystem in the eastern Mediterranean. We analyzed over 5000 fishing hauls digitalizing from fishers’ logbooks. We found that the catch per unit effort (CPUE) of alien species increased over time, while for indigenous species, CPUE remained relatively stable between 1996 and 2013. This suggests a lack of competitive exclusion of indigenous target species due to the proliferation of alien species. From the perspective of the fishers’ revenues, alien species gradually became a more important part of the catch, while overall fishers’ revenues showed temporal stability. This was the combined result of alien species increasing CPUE and fishers shifting their effort toward shallower water where alien species were dominant. Our findings demonstrate that alien species can become a valuable resource for a local fishing industry with little effect on indigenous species, which is highly relevant to worldwide fisheries experiencing range redistribution of commercial species.
... Invasive species have extensive negative impacts on the ecosystems they invade, such as losses in both taxonomic and functional diversity [3], resulting in severe economic consequences. For example, in the USA invasive insects cost the agricultural sector USD 13 billion per year due to crop loss and damage [4], routine activities to control Aedes mosquitoes in Cuba cost USD 16.80 per household [5], and Great Britain spends USD 34.6 million per year on the control of invasive fresh-water species [6]. The stakes are even higher when invasive species can vector pathogens that cause disease in humans, animals, or plants. ...
Article
Full-text available
We currently live in an era of major global change that has led to the introduction and range expansion of numerous invasive species worldwide. In addition to the ecological and economic consequences associated with most invasive species, invasive arthropods that vector pathogens (IAVPs) to humans and animals pose substantial health risks. Species distribution models that are informed using environmental Earth data are frequently employed to predict the distribution of invasive species, and to advise targeted mitigation strategies. However, there are currently substantial mismatches in the temporal and spatial resolution of these data and the environmental contexts which affect IAVPs. Consequently, targeted actions to control invasive species or to prepare the population for possible disease outbreaks may lack efficacy. Here, we identify and discuss how the currently available environmental Earth data are lacking with respect to their applications in species distribution modeling, particularly when predicting the potential distribution of IAVPs at meaningful space-time scales. For example, we examine the issues related to interpolation of weather station data and the lack of microclimatic data relevant to the environment experienced by IAVPs. In addition, we suggest how these data gaps can be filled, including through the possible development of a dedicated open access database, where data from both remotely- and proximally-sensed sources can be stored, shared, and accessed.
... IAS can alter ecosystem functioning by replacing, competing, or directly preying upon native species [1][2][3][4]. IAS can have a detrimental impact on agriculture, livestock farming, and, sometimes, human health [5][6][7], with significant impacts in terms of both social and economic costs for managing strategies [8][9][10][11][12]. ...
Article
Full-text available
The common ragweed Ambrosia artemisiifolia has spread throughout Europe since the 1800s, infesting croplands and causing severe allergic reactions. Recently, the ragweed leaf beetle Ophraella communa was found in Italy and Switzerland; considering that it feeds primarily on A. artemisiifolia in its invaded ranges, some projects started biological control of this invasive plant through the adventive beetle. In this context of a 'double' invasion, we assessed the influence of climate change on the spread of these alien species through ecological niche modelling. Considering that A. artemisiifolia mainly lives in agricultural and urbanized areas, we refined the models using satellite remote-sensing data; we also assessed the co-occurrence of the two species in these patches. A. artemisiifolia is predicted to expand more than O. communa in the future, with the medium and high classes of suitability of the former increasing more than the latter, resulting in lower efficacy for O. communa to potentially control A. artemisiifolia in agricultural and urbanized patches. Although a future assessment was performed through the 2018 land-cover data, the predictions we propose are intended to be a starting point for future assessments, considering that the possibility of a shrinkage of target patches is unlikely to occur.
... The spread of non-native invasive species is a globally important driver of ecosystem service and biodiversity loss. Freshwater ecosystems are often strongly impacted, with effects including reduced fisheries, reduced water availability for irrigation and municipal use, impeded navigation, and increased habitat for vectors of human disease (Pimental et al. 2005;Pejchar and Mooney 2009;Oreska and Aldridge 2011;Keller et al. 2018). Invasive freshwater crayfishes can have particularly large ecological and economic impacts. ...
Article
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Non-native crayfishes can have large impacts on biodiversity and the provisioning of ecosystem services in freshwaters. In 2015 we discovered an established population of the globally widespread red swamp crayfish (Procambarus clarkii) in the North Shore Channel of the Chicago Area Waterway System. This population overlaps with a population of rusty crayfish (Faxonius rusticus), a previous invader that is widely distributed and usually the dominant crayfish species across the Great Lakes region. If P. clarkii continues to spread in the Great Lakes region it will frequently encounter F. rusticus. Factors such as water clarity, competition for food when limited, and susceptibility to predation may alter P. clarkii’s ability to become established and spread. We sampled the overlapping populations and found that P. clarkii are significantly larger than F. rusticus. Next, we conducted lab experiments to examine the outcomes of competition between these species for shelter and food. F. rusticus were significantly more likely to seek shelter when threatened, while P. clarkii were significantly more likely to respond aggressively. P. clarkii won more competitions for food. Finally, we conducted field experiments to investigate rates of predation on each species and found that P. clarkii are predated significantly more often. Our results suggest that P. clarkii is dominant in interactions with F. rusticus but that higher rates of predation, likely occurring because P. clarkii is less likely to flee from threats, mitigate these benefits. We suggest that P. clarkii will dominate crayfish communities in water with low clarity, but not in clear-water habitats where visual predators are more effective.
... They may threaten human health by providing habitats for mosquitoes (O'Meara et al., 2003;Chandra et al., 2006). They also hamper recreational activities and disrupt agricultural production, causing great economic losses (Oreska and Aldridge, 2010;Rumlerova et al., 2016;Keller et al., 2018;Tanveer et al., 2018). Alien aquatic plants often compete for space, nutrients, and sediment fertilities with native macrophytes, thus hindering their reestablishment and decreasing diversity (Michelan et al., 2018;Silveira et al., 2018). ...
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Many alien aquatic plants are deliberately introduced because they have economic, ornamental, or environmental values; however, they may also negatively affect aquatic ecosystems, by blocking rivers, restricting aquatic animals and plants by decreasing dissolved oxygen, and reducing native biodiversity. These positive and/or negative ecological effects may be enhanced under global change. Here, we examine the impacts of global change on aquatic alien plant introduction and/or invasions by reviewing their introduction pathways, distributions, and ecological effects. We focus on how climate change, aquatic environmental pollution, and China’s rapid economic growth in recent decades affect their uses and invasiveness in China. Among 55 species of alien aquatic plants in China, 10 species are invasive, such as Eichhornia crassipes, Alternanthera philoxeroides, and Pistia stratiotes. Most of these invaders were intentionally introduced and dispersed across the country but are now widely distributed and invasive. Under climate warming, many species have expanded their distributions to areas where it was originally too cold for their survival. Thus, these species are (and will be) considered to be beneficial plants in aquaculture and for the restoration of aquatic ecosystems (for water purification) across larger areas. However, for potential invasive species, climate warming is (and will be) increasing their invasion risk in more areas. In addition, nitrogen deposition and phosphorus inputs may also alter the status of some alien species. Furthermore, climate warming has shifted the interactions between alien aquatic plants and herbivores, thus impacting their future spreads. Under climate change, more precipitation in North China and more frequent flooding in South China will increase the uncertainties of ecological effects of alien aquatic plants in these regions. We also predict that, under the continuing booming economy in China, more and more alien aquatic plants will be used for aquatic landscaping and water purification. In conclusion, our study indicates that both human activities under rapid economic growth and climate change can either increase the potential uses of alien aquatic plants or make the aquatic invaders worse in China and other areas in the world. These findings are critical for future risk assessment of aquatic plant introduction and aquatic ecosystem restoration.
... Management of Biological Invasions 10 (in press) native species and ecosystem services, with the associated management problems and economic costs (e.g. Oreska and Aldridge 2011;Caffrey et al. 2014;Gilioli et al. 2017) observed during recent decades. ...
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The European pond turtle Emys orbicularis is seriously threatened across Europe by the non-native common slider, Trachemys scripta, which is included among the 100 most invasive species worldwide. Using ensemble forecast techniques, we analysed the influence of climatic factors on the current distribution of these two species, subsequently projecting the obtained models under two Representative Concentration Pathways (RCPs) to 2050 and 2070, to investigate if global warming would boost direct competition within our study region. We implemented a gap analysis in GIS environment to assess how protected areas (PAs) may be affected by a loss of suitable area for E. orbicularis and by an expansion of T. scripta. An analysis of altitudinal range shift was evaluated, based on obtained projections. We found that both species may gain suitable area in the future, possibly because of the positive effect of increasing temperatures, and are predicted to shift from plain-to-hilly areas towards higher altitudes. These trends result in an increasing overlap of potentially suitable areas for both species, particularly within PAs; moreover, a niche analysis highlights that the results obtained are linked to the environmental niches of the two species. Our findings suggest the necessity, particularly for PAs' authorities, of field monitoring of T. scripta and further research to more comprehensively assess biotic and abiotic factors influencing the invasiveness of this species.
... Sessile Ponto-Caspian dreissenids, the zebra (Dreissena polymorpha (Pallas, 1771)) and quagga (Dreissena rostriformis bugensis Andrusov, 1897) mussels share similar habitats and food requirements (Quinn et al., 2013). They are invasive in Europe and North America, causing habitat changes and economic losses (Pimentel et al., 2005;Oreska and Aldridge, 2010;Ricciardi and MacIsaac, 2011). While in North America both species appeared within a few years, in Europe (apart from their native area) only the zebra mussel has occurred since the 19th century (Bidwell, 2010) until the recent spread of the quagga mussel in the second half of the 20th century ( Van der Velde et al., 2010). ...
Article
In invasive dreissenid communities, the zebra mussel usually appears earlier and then is displaced by the quagga mussel. We analysed length-weight allometric relationships, attachment strength (2 days, 1 week and 1 month of exposure), shell crushing resistance and glycogen content across the entire size range of both species in large shallow European lakes where this displacement has recently occurred. In Lake Balaton (Hungary) and Ijsselmeer (The Netherlands), the soft tissue dry weight increment of zebra mussels per unit length decreased after the quagga mussel invasion and became lower than that of quagga mussels. In Lake Markermeer (the Netherlands), having relatively worse environmental conditions, dry weight increment per unit length was always higher in quagga mussels than in zebra mussels, but no negative change in dry weight increment occurred in zebra mussels during the quagga mussel invasion. Small zebra mussels had more resistant shells and stronger attachment than quagga mussels. These differences were reduced (shell hardness) or reversed (long-term attachment) in larger individuals. Zebra mussels had lower glycogen content than quagga mussels across the entire size range. Thus, the quagga mussel advantage over zebra mussel likely consists in the faster dry weight increment per unit length and higher storage product contents of the former, due to its lower investments in attachment strength and shell crushing resistance.
... The impacts of invasive species are associated with a range of costs and benefits, with many species having both positive and negative values depending on the context (Goodenough, 2010;Oreska & Aldridge, 2011;Shackleton, Shackleton, & Kull, 2018). Impacts vary through space and through time. ...
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Invasive species are known to cause significant negative impacts to ecosystems and to people. In this paper, we outline the nature of these economic impacts, and then present a range of approaches for estimating the economic costs of invasive species (including impacts on biodiversity), and thus the benefits of management programmes. The importance of thinking clearly about the most appropriate context for valuation is stressed. We provide examples of the application of non‐market valuation approaches to invasive species management, and show how such methods can be used to measure public preferences over how control is undertaken. We discuss some important problems in applying economic valuation methods in this context.
... Alien and adventive species are major threats to many natural and human-managed ecosystems, in terms of biodiversity conservation (Crowl et al., 2008;Bellard et al., 2016;Gilioli et al., 2017), socio-economic costs and management efforts (Williams et al., 2010;Oreska and Aldridge, 2011;Early et al., 2016). The successful establishment of an invasive alien species depends on many environmental variables, which can be summarized in the BAM diagram (Soberon and Peterson, 2005); the research in this field is very active, and many analytical approaches are used. ...
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New records for the adventive species Monoxia obesula Blake (Coleoptera Chrysomelidae Galerucinae) in the Mediterranean region are reported. An Ecological Niche Modeling (ENM) analysis to estimate the potential distribution of this leaf beetle in the secondary range, through the assessment of the habitat suitability, was performed. The expected distribution, as predicted by the ENM analysis, is rather limited in the Mediterranean region, with high suitability areas only in southern Spain, Sardinia, Sicily, southern peninsular Italy, Tunisia and Egypt. Nevertheless, the Ensemble Models for future climatic conditions predict an expansion from all the currently suitable territories of the Mediterranean region, especially in coastal areas.
... The spread of invasive macrophyte species is considered to be one of the most detrimental human impacts on inland waters across the globe (Strayer, 2010;Reid A. J. et al., 2018) Invasive macrophyte species are alien species living outside their natural range. They create self-replacing populations over several life cycles, reducing freshwater biodiversity (Boylen et al., 1999;Ailstock et al., 2001;Houlahan and Findlay, 2004), stimulating plant biomass production (Farnsworth and Ellis, 2001;Kelly and Hawes, 2005), altering biogeochemical cycles (Templer et al., 1998;Angeloni et al., 2006) and causing millions of dollars (e.g., > US$30 million year−1 in the UK; Oreska and Aldridge, 2011) in damages and ecosystem remediation (Strayer and Dudgeon, 2010). The distinctive plant structure and high biomass of most invasive macrophytes can further cause strong and varied ecosystem engineering effects (Crooks, 2002;Yarrow et al., 2009). ...
Article
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The spread of invasive macrophyte species is a pressing threat to neotropical shallow lakes. Yet there are few studies addressing the full extent of biotic and abiotic changes that may occur in response to invasive species. Less is known of how other human-induced stressors such as eutrophication and lake draining may interact over time with invasive macrophytes to influence biodiversity. We combined limnological observations with paleoecological data from Fúquene Lake, Colombia, a eutrophic neotropical shallow lake, to provide information on the current and long-term (decades-centuries) dynamics of the spread of two well-established invasive plants Eichhornia crassipes and Egeria densa. We found a unique in macrophyte species composition in areas currently dominated by Egeria and Eichhornia. Eichhornia-dominated areas had 14 macrophyte species, turbid (secchi=19 ± 6 cm) and poorly oxygenated (3.94 ± 2.61 ppm) waters whereas Egeria-rich areas supported 5 species and had clearer (secchi=51 ± 12 cm) and better-oxygenated (6.06 ± 2.4 ppm) waters. Historical macrophyte community shifts were linked to eutrophication and lake level variation and characterized by the loss of charophytes and bryophytes before 1500 CE and subsequent reductions in Nymphaea sp., Potamogeton illinoensis and Najas guadalupensis in the early 1900s (lake draining). Eichhornia crassipes (since 1500 CE) and E. densa (early 1900s) occurred well before proposed dates of introduction (1950s and 1990 respectively). Both species have rapidly expanded since the 1990s along with Azolla filiculoides in response to an inflow water diversion scheme and heavy nutrient loads. Our results suggest that the spread of Eichhornia and Egeria was not responsible for native macrophyte species loss, but that their current dominance is exerting synergistic and antagonistic secondary effects on plant assemblages through habitat modification, competitive exclusion and promotion of habitat heterogeneity across the lake. It could therefore be misleading to suggest that invasive plants causes macrophyte species loss in degraded lakes. We suggest that aggressive species like Eichhornia, Azolla, and Egeria require hydrologically stable and eutrophic environments to spread; thus, management actions should focus on controlling these two factors. Our study demonstrates the need to use a long-term approach to fully-understand the effects of invasive macrophytes.
... Well known invaders of SWBs include Himalayan balsam Impatiens glandulifera, Japanese knotweed Fallopia japonica, Canadian pondweed Elodea canadensis and goldfish Carassius auratus. The estimated cost to control invasive pondweeds in Great Britain is over £11.6 m y −1 (Oreska and Aldridge, 2011). ...
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Small, 1st and 2nd-order, headwater streams and ponds play essential roles in providing natural flood control, trapping sediments and contaminants, retaining nutrients, and maintaining biological diversity, which extend into downstream reaches, lakes and estuaries. However, the large geographic extent and high connectivity of these small water bodies with the surrounding terrestrial ecosystem makes them particularly vulnerable to growing land-use pressures and environmental change. The greatest pressure on the physical processes in these waters has been their extension and modification for agricultural and forestry drainage, resulting in highly modified discharge and temperature regimes that have implications for flood and drought control further downstream. The extensive length of the small stream network exposes rivers to a wide range of inputs, including nutrients, pesticides, heavy metals, sediment and emerging contaminants. Small water bodies have also been affected by invasions of non-native species, which along with the physical and chemical pressures, have affected most groups of organisms with consequent implications for the wider biodiversity within the catchment. Reducing the impacts and restoring the natural ecosystem function of these water bodies requires a three-tiered approach based on: restoration of channel hydromorphological dynamics; restoration and management of the riparian zone; and management of activities in the wider catchment that have both point-source and diffuse impacts. Such activities are expensive and so emphasis must be placed on integrated programmes that provide multiple benefits. Practical options need to be promoted through legislative regulation, financial incentives, markets for resource services and voluntary codes and actions.
... These include horizon scanning and monitoring of the most likely future invaders to help prevent introductions, the actual prevention of future introductions by reducing pathways, intercepting movements at borders and assessing risk for intentional imports, and early warning, eradication and long-term control measures when prevention fails (Simberloff et al. 2013). As eradication of established INNS in natural habitats has proved impossible or extremely costly in most cases (Myers et al. 2000;Zavaleta et al. 2001;Mack and Lonsdale 2002;Britton et al. 2011;Oreska and Aldridge 2011;Pluess et al. 2012), implementation of proactive approaches that focus efforts on preventing introductions has been shown to provide considerable conservation and economic benefits (Simberloff et al. 2013). This approach has manifested in several recent trans-national legislations, including the Convention on Biological Diversity's Aichi biodiversity target for 2020 (Secretariat of the Convention on Biological Diversity 2011) listing the management of introduction pathways in the key target #9 (Anderson et al. 2014), and the European Union Regulation No 1143/2014 on the prevention and management of the introduction and spread of INNS (European Commission 2014; Genovesi et al. 2015). ...
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We assessed how establishment patterns of non-native freshwater, marine and terrestrial species into Northwest Europe (using Great Britain, France, Belgium and the Netherlands as the study countries) have changed over time, and identified the prevalent pathways and vectors of recent arrivals. Data were extracted from 33 sources on (a) presence/absence and (b) first year of observation in the wild in each country, and (c) continent(s) of origin, (d) invasion pathway(s), (e) invasion vector(s) and (f) environment(s) for 359 species, comprising all non-native Mollusca, Osteichthyes (bony fish), Anseriformes (wildfowl) and Mammalia, and non-native invasive Angiospermae present in the area. Molluscs, fish and wildfowl, particularly those originating from South America, arrived more recently into Northwest Europe than other groups, particularly mammals, invasive plants and species originating from North America. Non-deliberate introductions, those of aquatic species and those from elsewhere in Europe and/or Asia increased strongly in importance after the year 2000 and were responsible for 69, 83 and 89 % of new introductions between 2001 and 2015, respectively. Non-deliberate introductions and those from Asia and North America contributed significantly more to introductions of invasive species in comparison to other non-native species. From the 1960s, ornamental trade has increased in importance relative to other vectors and was responsible for all deliberate introductions of study groups since 2001. Non-deliberate introductions of freshwater and marine species originating from Southeast Europe and Asia represent an increasingly important ecological and economic threat to Northwest Europe. Invertebrates such as molluscs may be particularly dangerous due to their small size and difficulties in detection. Prevention of future invasions in this respect will require intensive screening of stowaways on boats and raising of public awareness.
... Biological invasion of our native ecosystems by nonindigenous alien invasive species is one of the most pertinent problems of the present era (McNeely 2001;Vilà et al. 2010). Invasive species may lead to ecosystem degradation and impairment of ecosystem services in non-native regions (Pysek and Richardson 2010) and inflict high negative ecological and economic impacts (Pimentel et al. 2005, Oreska andAldridge 2011).The problem of biological invasion is especially crucial for the tropical ecosystems of the world since the tropics are one of the richest biodiversity hotspots with about 13% of all plant diversity in just 0.2% of the total land area of the planet (Myers 1988, Mittermeier et al. 1998). Freshwater ecosystems, which cover approximately 0.8% of the earth's surface, but support almost 6% of all described species, are especially vulnerable to human activities (Dudgeon et al. 2006). ...
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Tropical freshwater ecosystems;an indispensible means of sustenance, food and livelihood for millions of poor people of the developing world;are prone to massive biodiversity declines due to huge pressures of over-exploitation and invasive species.Without mitigation of the problem of biological invasion of the tropics, half the world's population will be soon facing serious food shortages.In an attempt to bridge the gap between successful management of an invasive plant, and a sustainable source of supplementary food for the marginalized population, this pilot study investigated the potential utilizationof the widely prevalent invasive Alternanthera philoxeroides (Alligatorweed) as a leafy vegetable. Questionnaire-based field-surveys revealed a much higher section of rural populace utilized Alligatorweed as food/fodder as compared to the urban/semi-urban populace. ED-XRF analysis of young ‘edible’ shoots of Alligatorweed revealed it to have good concentration of essential elements likepotassium, calcium, iron, zinc and manganese. However, significant positive correlations of manganese (p<0.01) between Alligatorweed and its soil-substratum indicated its metal hyper-accumulative potential. Hence, Alligatorweed should be used for human-consumption only when it is harvested from non-polluted eco-regions. This study explores a positive utility of the invasive Alligatorweed and in turn indicates its possible managerial approach. In a country where a large populace is malnourished, consumption of Alligatorweed as supplementary-vegetable can not only help in controlling its invasion into our pristine aquatic/wetland ecosystems, but also help in generation of cheap and sustainable source of supplementary food for the marginalized section of our country.
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As strategic transport infrastructures, canals provide wide-ranging economic benefits as well as save energy and reduce CO2 emissions. At the same time, by connecting previously biogeographically-isolated systems, they serve as corridors for the introduction and spread of aquatic alien species, potentially leading to unforeseen ecological and economic impacts. To date, there has been no attempt to quantify the reported economic costs of these species. Here, we used the InvaCost database on the monetary impact of invasive alien species to identify the costs of species whose introduction and spread have been linked to the operation of three major canal systems: the European Inland Canals, Suez Canal and Panama Canal. While we identified a staggering number of alien species that have been spread via these systems, monetary costs have been reported only for a few of these known invasive aliens. A total of $33.6 million in costs have been reported from invasive species linked to European Inland Canals (the fishhook waterflea Cercopagis pengoi and the zebra mussel Dreissena polymorpha) and $8.6 million linked to the Suez Canal (the silver-cheeked toadfish Lagocephalus sceleratus, the lionfish Pterois miles, and the nomad jellyfish Rhopilema nomadica), but no recorded costs were yet recorded for species which invasion was facilitated by the Panama Canal. We thus identified a pervasive lack of information on the monetary costs of invasions facilitated by anthropogenically-created corridors, such as canals. In highlighting the uneven and lacking distribution of costs, we suggest those benefiting from the creation of canals are not necessarily the same as those paying the incurred costs, and urge greater recognition and reporting of impacts.
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The impacts of invasive alien species are well-known and are categorised as a leading contributor to biodiversity loss globally. However, relatively little is known about the monetary costs incurred from invasions on national economies, hampering management responses. In this study, we used published data to describe the economic cost of invasions in Southeast Asia, with a focus on Singapore – a biodiversity-rich, tropical island city state with small size, high human density and high trade volume, three factors likely to increase invasions. In this country, as well as in others in Southeast Asia, cost data were scarce, with recorded costs available for only a small fraction of the species known to be invasive. Yet, the overall available economic costs to Singapore were estimated to be ~ US$ 1.72 billion in total since 1975 (after accounting for inflation), which is approximately one tenth of the total cost recorded in all of Southeast Asia (US$ 16.9 billion). These costs, in Singapore and Southeast Asia, were mostly linked to insects in the family Culicidae (principally Aedes spp.) and associated with damage, resource loss, healthcare and control-related spending. Projections for 11 additional species known to be invasive in Singapore, but with recorded costs only from abroad, amounted to an additional US$ 893.13 million, showing the potential huge gap between recorded and actual costs (cost records remain missing for over 90% of invasive species). No costs within the database for Singapore – or for other Southeast Asian countries – were exclusively associated with proactive management, highlighting that a shortage of reporting on the costs of invasions is mirrored by a lack of investment in management. Moreover, invasion cost entries in Singapore were under-reported relative to import levels, but total costs exceeded expectations, based on land area and population size, and to a greater extent than in other Southeast Asian countries. Therefore, the evaluation and reporting of economic costs of invasions need to be improved in this region to provide efficient data-based support for mitigation and management of their impacts.
Technical Report
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In light of new legislation surrounding the control and management of Invasive Non-Native Species (INNS), this UKWIR project has assessed the potential new obligations for the UK water industry and explores its’ role in meeting legal and social requirements. In the context of the new legislation, the objectives of the research work were to: • Establish emergent threats from INNS for the period 2015 to 2030 (AMP 6 to AMP 8) • Quantify potential operational difficulties and cost liabilities to water companies • Codify water company responsibilities with regard to INNS; and • Recommend the most effective measures (for prevention, management, control and eradication) available to water companies bearing in mind constraints around drinking water safety and the health and safety of staff exercising such controls. Five key recommendations to the Industry are made for the future management of INNS: • The development of pathway management plans • The integration of companywide biosecurity policies into business as usual operations including supply chain management • Delivery of preventative surveillance monitoring programmes • Provision of appropriate wash down facilities; and • Continuation of targeted stakeholder engagement.
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Recent comprehensive data provided through the DAISIE project (www.europe-aliens.org) have facilitated the development of the first pan-European assessment of the impacts of alien plants, vertebrates, and invertebrates — in terrestrial, freshwater, and marine environments — on ecosystem services. There are 1094 species with documented ecological impacts and 1347 with economic impacts. The two taxonomic groups with the most species causing impacts are terrestrial invertebrates and terrestrial plants. The North Sea is the maritime region that suffers the most impacts. Across taxa and regions, ecological and economic impacts are highly correlated. Terrestrial invertebrates create greater economic impacts than ecological impacts, while the reverse is true for terrestrial plants. Alien species from all taxonomic groups affect "supporting", "provisioning", "regulating", and "cultural" services and interfere with human well-being. Terrestrial vertebrates are responsible for the greatest range of impacts, and these are widely distributed across Europe. Here, we present a review of the financial costs, as the first step toward calculating an estimate of the economic consequences of alien species in Europe.
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ABSTRACT Invading non-indigenous species in the United States cause major environmental damages,and losses adding up to more than $138 billion per year. There are approximately 50,000 foreign species and the number is increasing. About 42% of the species on the Threatened or Endangered species lists are at risk primarily because of non-indigenous species. In the history of the United States, approximately 50,000 non-indigenous (non-native)
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The fight against invasive alien plant species goes on largely unnoticed in the UK, though their impacts on native biodiversity, infrastructure and the economy are occasionally headline news. Traditional techniques such as manual and chemical control are often insufficient in suppressing large weed populations, or else not desirable or permitted in sensitive conservation areas. Current research into classical biological control of some of the UK's most pernicious weeds could offer a sustainable and ecologically-sensitive alternative tool for weed management.
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Over 120,000 non-native species of plants, animals and microbes have invaded the United States, United Kingdom, Australia, South Africa, India, and Brazil, and many have caused major economic losses in agriculture and forestry as well as negatively impacting ecological integrity. Some introduced species, like corn (Zea mays L.), wheat (Triticum spp.), rice (Oryza sativa L.), plantation forests, domestic chicken (Gallus spp.), cattle (Bos taurus), and others, are beneficial and provide more than 98% of the world’s food supply. Precise economic costs associated with some of the most ecologically damaging alien species are not available. Cats (Felis cattus) and pigs (Sus scrofa), for example, are responsible for the extinction of various animal species, however, it is impossible to assign monetary values to species forced to extinction. The estimate is that non-native species invasions in the six nations are causing more than US$ 314 billion per year in damages.
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Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with large effects in order to prioritize management efforts. This paper focuses on defining, evaluating, and comparing a variety of measures of impact drawn from empirical examples and theoretical reasoning. We begin by arguing that the total impact of an invader includes three fundamental dimensions: range, abundance, and the per-capita or per-biomass effect of the invader. Then we summarize previous approaches to measuring impact at different organizational levels, and suggest some new approaches. Reviewing mathematical models of impact, we argue that theoretical studies using community assembly models could act as a basis for better empirical studies and monitoring programs, as well as provide a clearer understanding of the relationship among different types of impact. We then discuss some of the particular challenges that come from the need to prioritize invasive species in a management or policy context. We end with recommendations about how the field of invasion biology might proceed in order to build a general framework for understanding and predicting impacts. In particular, we advocate studies designed to explore the correlations among different measures: Are the results of complex multivariate methods adequately captured by simple composite metrics such as species richness? How well are impacts on native populations correlated with impacts on ecosystem functions? Are there useful bioindicators for invasion impacts? To what extent does the impact of an invasive species depend on the system in which it is measured? Three approaches would provide new insights in this line of inquiry: (1) studies that measure impacts at multiple scales and multiple levels of organization, (2) studies that synthesize currently available data on different response variables, and (3) models designed to guide empirical work and explore generalities.
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The purpose of this paper is to present the economic analysis and research on invasive species management, which implies, in principle, a focus on two main questions: (i) how to set targets for species damage mitigation? and (ii) which policy instruments are best in achieving the target(s)? The results indicated that a majority of the studies recognize the need for addressing the links between economic and ecological systems and accounting for the uncertainty associated with predicting damages from invasive species. A common result is that strategies for prevention, control and damage reduction are complementary, and neglect of any of them may lead to unnecessary large social costs. Furthermore, unless economy-wide adjustments are accounted for when designing tariffs on imports, counter-active results may occur where the risk of invasive species damage increases. However, due to insufficient availability of data on the environmental impacts of alien invasive spe-cies, there is a lack of empirical applications.