Invasive alien species are a major problem for managers of protected areas (PAs) worldwide. Until the 1980s biological invasions were widely considered to be largely confined to anthropogenically ...disturbed sites and the widespread disruption of ecosystems in PAs by invasive species was not globally perceived as a major threat. A working group of the SCOPE program on biological invasions in the 1980s showed that PAs are not spared from major disruptive effects of invasions. Early research focused on descriptive studies of the extent to which PAs were invaded. More recent research explored drivers of invasion, and in the last decade much work has focused on understanding the impacts of invasions. We review the current understanding of alien plant invasions in PAs, focusing on four themes: (1) the status and macroecological patterns of alien plant invasions; (2) the threats that invasive alien plants (IAPs) pose and the impacts detected to date; (3) the current focus of invasion science in PAs; and (4) research priorities for advancing science-based management and policy. Of a sample of 59 widespread IAP species from a representative sample of 135 PAs globally, trees make up the largest proportion (32%), followed by perennial herbs (17%) and shrubs (15%). About 1857 papers have been published on alien species in PAs; 45% have focused on alien plants. Some textbook examples of impacts by IAPs originate from PAs, illustrating the severe threat to the core function of PAs. Impacts have been quantified at the species and community levels through the displacement and alteration of habitats. In some cases, native species abundance, diversity and estimated species richness have been altered, but reversed following control. At an ecosystem level, invasive plants have radically altered fire regimes in several PAs, in some cases causing regime shifts and transforming woodlands or savannas to grasslands. Invasions have also had a major impact on nutrient cycles. Protected areas are performing an increasingly important part of the global response to stem the rate of environmental change. Despite this, integrated efforts involving science, management and policy that are sufficiently resourced to generate insights on the status and dynamics of IAPs in PAs are insufficient or even lacking. Such efforts are needed to pave the way for monitoring trends, revising legislation and policies, and improving management interventions to reduce the extent and magnitude of impacts of invasive plants in PAs. While policy instruments to support management of non-native species date back to the 1930s, there has been a substantial increase in legislative support and general awareness since the early 2000s. Still, opportunities to improve research for PAs need to be created. Towards this goal, the establishment of a global PA research network could provide a unique vehicle to explore questions across species or functional groups and systems, at a scale currently beyond existing abilities. Developing an integrated global database with standardized, quantitative information could form part of such a networks function.
Scientists' warning on invasive alien species Pyšek, Petr; Hulme, Philip E.; Simberloff, Dan ...
Biological reviews of the Cambridge Philosophical Society,
December 2020, Letnik:
95, Številka:
6
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ABSTRACT
Biological invasions are a global consequence of an increasingly connected world and the rise in human population size. The numbers of invasive alien species – the subset of alien species ...that spread widely in areas where they are not native, affecting the environment or human livelihoods – are increasing. Synergies with other global changes are exacerbating current invasions and facilitating new ones, thereby escalating the extent and impacts of invaders. Invasions have complex and often immense long‐term direct and indirect impacts. In many cases, such impacts become apparent or problematic only when invaders are well established and have large ranges. Invasive alien species break down biogeographic realms, affect native species richness and abundance, increase the risk of native species extinction, affect the genetic composition of native populations, change native animal behaviour, alter phylogenetic diversity across communities, and modify trophic networks. Many invasive alien species also change ecosystem functioning and the delivery of ecosystem services by altering nutrient and contaminant cycling, hydrology, habitat structure, and disturbance regimes. These biodiversity and ecosystem impacts are accelerating and will increase further in the future. Scientific evidence has identified policy strategies to reduce future invasions, but these strategies are often insufficiently implemented. For some nations, notably Australia and New Zealand, biosecurity has become a national priority. There have been long‐term successes, such as eradication of rats and cats on increasingly large islands and biological control of weeds across continental areas. However, in many countries, invasions receive little attention. Improved international cooperation is crucial to reduce the impacts of invasive alien species on biodiversity, ecosystem services, and human livelihoods. Countries can strengthen their biosecurity regulations to implement and enforce more effective management strategies that should also address other global changes that interact with invasions.
Eradication of alien species is a key conservation tool to mitigate the impacts caused by biologic invasions. The aim of the present paper is to review the eradications successfully completed in ...Europe and to discuss the main limits to a wider application of this management option in the region. On the basis of the available literature - including conference proceedings, national reports to the Bern Convention, etc. - a total of 37 eradication programmes have been recorded. Thirty-three eradications were carried out on islands and four on the mainland. The rat (Rattus spp.) has been the most common target (n = 25, 67%), followed by the rabbit (n = 4). In many cases, these eradications determined a significant recovery of native biodiversity. Differently to other regions of the world, no eradications of alien invertebrates and marine organisms have been recorded; regarding invasive alien plants, it appears that only some very localized removals have been completed so far in Europe. The limited number of eradications carried out in Europe so far is probably due to the limited awareness of the public and the decision makers, the inadequacy of the legal framework, and the scarcity of resources. Synthetic guidelines for improving the ability of European states to respond to aliens incursions are presented.PUBLICATION ABSTRACT
Prioritization is indispensable for the management of biological invasions, as recognized by the Convention on Biological Diversity, its current strategic plan, and specifically Aichi Target 9 that ...concerns invasive alien species. Here we provide an overview of the process, approaches and the data needs for prioritization for invasion policy and management, with the intention of informing and guiding efforts to address this target. Many prioritization schemes quantify impact and risk, from the pragmatic and action-focused to the data-demanding and science-based. Effective prioritization must consider not only invasive species and pathways (as mentioned in Aichi Target 9), but also which sites are most sensitive and susceptible to invasion (not made explicit in Aichi Target 9). Integrated prioritization across these foci may lead to future efficiencies in resource allocation for invasion management. Many countries face the challenge of prioritizing with little capacity and poor baseline data. We recommend a consultative, science-based process for prioritizing impacts based on species, pathways and sites, and outline the information needed by countries to achieve this. This should be integrated into a national process that incorporates a broad suite of social and economic criteria. Such a process is likely to be feasible for most countries.
Impacts of biological invasions: what's what and the way forward Simberloff, Daniel; Martin, Jean-Louis; Genovesi, Piero ...
Trends in ecology & evolution (Amsterdam),
January 2013, 2013, 2013-Jan, 2013-01-00, 20130101, 2013-01-01, Letnik:
28, Številka:
1
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Study of the impacts of biological invasions, a pervasive component of global change, has generated remarkable understanding of the mechanisms and consequences of the spread of introduced ...populations. The growing field of invasion science, poised at a crossroads where ecology, social sciences, resource management, and public perception meet, is increasingly exposed to critical scrutiny from several perspectives. Although the rate of biological invasions, elucidation of their consequences, and knowledge about mitigation are growing rapidly, the very need for invasion science is disputed. Here, we highlight recent progress in understanding invasion impacts and management, and discuss the challenges that the discipline faces in its science and interactions with society.
Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to ...recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact-ranging from Minimal to Massive-with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions.
Biological invasions are among the greatest threats to global biodiversity, but in contrast to most other global threats, they suffer from specific communication issues. Our paper presents the first ...new addition to the widely cited IUCN list of “100 of the world’s worst invasive species”, a list created a decade ago in response to these communication issues. We briefly present this list, the recent removal of one species from that list, and the rationale to include a novel, 100th species to replace it. The new species of this list, giant salvinia (
Salvinia molesta
), was chosen by the community of invasion biologists (over 650 experts from over 60 countries). This new addition to the list will draw public attention to the damage caused by invasive alien species and it will help stimulate the necessary discussion of this critical issue in science and policy circles.
More than US$21 billion is spent annually on biodiversity conservation. Despite their importance for preventing or slowing extinctions and preserving biodiversity, conservation interventions are ...rarely assessed systematically for their global impact. Islands house a disproportionately higher amount of biodiversity compared with mainlands, much of which is highly threatened with extinction. Indeed, island species make up nearly two-thirds of recent extinctions. Islands therefore are critical targets of conservation. We used an extensive literature and database review paired with expert interviews to estimate the global benefits of an increasingly used conservation action to stem biodiversity loss: eradication of invasive mammals on islands. We found 236 native terrestrial insular faunal species (596 populations) that benefitted through positive demographic and/or distributional responses from 251 eradications of invasive mammals on 181 islands. Seven native species (eight populations) were negatively impacted by invasive mammal eradication. Four threatened species had their International Union for the Conservation of Nature (IUCN) Red List extinction-risk categories reduced as a direct result of invasive mammal eradication, and no species moved to a higher extinction-risk category. We predict that 107 highly threatened birds, mammals, and reptiles on the IUCN Red List—6% of all these highly threatened species—likely have benefitted from invasive mammal eradications on islands. Because monitoring of eradication outcomes is sporadic and limited, the impacts of global eradications are likely greater than we report here. Our results highlight the importance of invasive mammal eradication on islands for protecting the world’s most imperiled fauna.
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.
Our ability to predict invasions has been hindered by the seemingly idiosyncratic context-dependency of individual invasions. However, we argue that robust and useful generalisations in invasion ...science can be made by considering “invasion syndromes” which we define as “a combination of pathways, alien species traits, and characteristics of the recipient ecosystem which collectively result in predictable dynamics and impacts, and that can be managed effectively using specific policy and management actions”. We describe this approach and outline examples that highlight its utility, including: cacti with clonal fragmentation in arid ecosystems; small aquatic organisms introduced through ballast water in harbours; large ranid frogs with frequent secondary transfers; piscivorous freshwater fishes in connected aquatic ecosystems; plant invasions in high-elevation areas; tall-statured grasses; and tree-feeding insects in forests with suitable hosts. We propose a systematic method for identifying and delimiting invasion syndromes. We argue that invasion syndromes can account for the context-dependency of biological invasions while incorporating insights from comparative studies. Adopting this approach will help to structure thinking, identify transferrable risk assessment and management lessons, and highlight similarities among events that were previously considered disparate invasion phenomena.
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