Stochasticity can play an important role in the dynamics of biologically relevant populations. These span a broad range of scales: from intra-cellular populations of molecules to population of cells ...and then to groups of plants, animals and people. Large deviations in stochastic population dynamics-such as those determining population extinction, fixation or switching between different states-are presently in a focus of attention of statistical physicists. We review recent progress in applying different variants of dissipative WKB approximation (after Wentzel, Kramers and Brillouin) to this class of problems. The WKB approximation allows one to evaluate the mean time and/or probability of population extinction, fixation and switches resulting from either intrinsic (demographic) noise, or a combination of the demographic noise and environmental variations, deterministic or random. We mostly cover well-mixed populations, single and multiple, but also briefly consider populations on heterogeneous networks and spatial populations. The spatial setting also allows one to study large fluctuations of the speed of biological invasions. Finally, we briefly discuss possible directions of future work.
Invasive plant species that have the potential to alter fire regimes have significant impacts on native ecosystems. Concern that pine invasions in the Southern Hemisphere will increase fire activity ...and severity and subsequently promote further pine invasion prompted us to examine the potential for feedbacks between Pinus contorta invasions and fire in Patagonia and New Zealand. We determined how fuel loads and fire effects were altered by P. contorta invasion. We also examined post-fire plant communities across invasion gradients at a subset of sites to assess how invasion alters the post-fire vegetation trajectory. We found that fuel loads and soil heating during simulated fire increase with increasing P. contorta invasion age or density at all sites. However, P. contorta density did not always increase post-fire. In the largest fire, P. contorta density only increased significantly post-fire where the pre-fire P. contorta density was above an invasion threshold. Below this threshold, P. contorta did not dominate after fire and plant communities responded to fire in a similar manner as uninvaded communities. The positive feedback observed at high densities is caused by the accumulation of fuel that in turn results in greater soil heating during fires and high P. contorta density post-fire. Therefore, a positive feedback may form between P. contorta invasions and fire, but only above an invasion density threshold. These results suggest that management of pine invasions before they reach the invasion density threshold is important for reducing fire risk and preventing a transition to an alternate ecosystem state dominated by pines and novel understory plant communities.
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BFBNIB, FZAB, GIS, IJS, INZLJ, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Conserving biodiversity in the face of ever-increasing human pressure is hampered by our lack of basic information on species occurrence, distribution, abundance, habitat requirements, and threats. ...Obtaining this information requires efficient and sensitive methods capable of detecting and quantifying true occurrence and diversity, including rare, cryptic and elusive species. Environmental DNA (eDNA) is an emerging technique that can increase our ability to detect and quantify biodiversity, by overcoming some of the challenges of labor-intensive traditional surveys. The application of eDNA in ecology and conservation has grown enormously in recent years, but without a concurrent growth in appreciation of its strengths and limitations. In many situations, eDNA may either not work, or it may work but not provide the information needed. Problems with (1) imperfect detection, (2) abundance quantification, (3) taxonomic assignment, (4) eDNA spatial and temporal dynamics, (5) data analysis and interpretation, and (6) assessing ecological status have all been significant. The technique has often been used without a careful evaluation of the technical challenges and complexities involved, and a determination made that eDNA is the appropriate method for the species or environment of interest. It is therefore important to evaluate the scope and relevance of eDNA-based studies, and to identify critical considerations that need to be taken into account before using the approach. We review and synthesize eDNA studies published to date to highlight the opportunities and limitations of utilizing eDNA in ecology and conservation. We identify potential ways of reducing limitations in eDNA analysis, and demonstrate how eDNA and traditional surveys can complement each other.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
To reduce the impact of biological invasions, we need to understand the behavioural mechanisms that enable some species to be successful invaders. Testing differences in behaviour between sympatric ...congeneric species with different invasive potential is an opportunity to study specific behavioural traits associated with invasion success. Using the invasive Italian wall lizard, Podarcis sicula, and a noninvasive congeneric, the green Iberian wall lizard, Podarcis virescens, which live in sympatry in a location that is novel for P. sicula, we tested their exploratory behaviour, neophobia and boldness: all traits that should promote invasion success. The invasive P. sicula was more exploratory, bold and neophilic than the sympatric native P. virescens. Native lizards had highly repeatable behaviour, whereas in P. sicula boldness was the only behavioural trait that was repeatable. The behavioural traits of the native species, but not the invasive species, were correlated. A lack of correlation between behavioural traits, as well as a lack of repeatability in two of the three behavioural traits, suggests higher levels of behavioural plasticity in P. sicula, which may also explain the success of this lizard during invasions. Our experiment highlights the potential importance of behavioural traits in invasions and provides insight into why P. sicula is such a successful invader.
•Invasive lizards are more exploratory, bold and neophilic than a noninvasive species.•Behaviour of native lizards was repeatable for all three behavioural traits.•Only boldness was repeatable for the invasive lizard.•Suggests greater plasticity in invasive species, important for invasion success.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims ...to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta‐analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat alteration). Considering the strong trophic links that characterize aquatic ecosystems, this framework is relevant to anticipate the far‐reaching consequences of biological invasions on the structure and functionality of aquatic ecosystems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Alien species can have major ecological and socioeconomic impacts in their novel ranges and so effective management actions are needed. However, management can be contentious and create conflicts, ...especially when stakeholders who benefit from alien species are different from those who incur costs. Such conflicts of interests mean that management strategies can often not be implemented. There is, therefore, increasing interest in engaging stakeholders affected by alien species or by their management. Through a facilitated workshop and consultation process including academics and managers working on a variety of organisms and in different areas (urban and rural) and ecosystems (terrestrial and aquatic), we developed a framework for engaging stakeholders in the management of alien species. The proposed framework for stakeholder engagement consists of 12 steps: (1) identify stakeholders; (2) select key stakeholders for engagement; (3) explore key stakeholders' perceptions and develop initial aims for management; (4) engage key stakeholders in the development of a draft management strategy; (5) re-explore key stakeholders' perceptions and revise the aims of the strategy; (6) co-design general aims, management objectives and time frames with key stakeholders; (7) co-design a management strategy; (8) facilitate stakeholders' ownership of the strategy and adapt as required; and (9) implement the strategy and monitor management actions to evaluate the need for additional or future actions. In case additional management is needed after these actions take place, some extra steps should be taken: (10) identify any new stakeholders, benefits, and costs; (11) monitor engagement; and (12) revise management strategy. Overall, we believe that our framework provides an effective approach to minimize the impact of conflicts created by alien species management.
•Conflicts of interest can prevent the success of invasive species management actions.•Stakeholder engagement may avoid conflicts on interests.•A 12-step framework for stakeholder engagement is discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Aim: Niche-based species distribution models (SDMs) are commonly used to predict impacts of global change on biodiversity, but the reliability of these predictions in space and time depends on their ...transferability. We tested how the strategy used to choose predictors impacts the transferability of SDMs at a cross-continental scale. Location: North America, Eurasia and Australia. Method: We used a systematic approach including 50 Holarctic plant invaders and 27 initial predictorvariables, considering 10 different strategies for variable selection, accounting for the proximality, multicollinearity and climate analogy of predictors. We compared the average performance of each strategy, some of which used a large number of predictor combinations. Next, we looked for the single best model for each species across all the predictor combinations retained in the analysis. Transferability was considered as the predictive success of SDMs calibrated in the native range and projected onto the invaded range. Results: Two strategies showed better SDM transferability on average: a set of predictors known for their ecologically meaningful effects on plant distribution, and the two first axes of a principal component analysis calibrated on all predictor variables (Spc2). From the more than 2000 combinations of predictors per species across strategies, the best set of predictors yielded SDMs with good transferability for 45 species (90%). These best combinations consisted of eight randomly assembled (39 species) or uncorrelated predictors (6 species) and Spc2 (5 species). We also found that internal cross-validation was not sufficient to give full information about the transferability of a SDM to a distinct range. Main conclusion: Transferring SDMs at the macroclimatic scale, and thus anticipating invasions, is possible for the large majority of invasive plants considered in this study, but the accuracy of the predictions relies strongly on the choice of predictors. From our results, we recommend including either proximal and state-of-the-art variables or a reduced and orthogonalized set to obtain robust SDM projections.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
As part of national biosecurity programs, cargo imports, passenger baggage, and international mail are inspected at ports of entry to verify compliance with phytosanitary regulations and to intercept ...potentially damaging nonnative species to prevent their introduction. Detection of organisms during inspections may also provide crucial information about the species composition and relative arrival rates in invasion pathways that can inform the implementation of other biosecurity practices such as quarantines and surveillance. In most regions, insects are the main taxonomic group encountered during inspections. We gathered insect interception data from nine world regions collected from 1995 to 2019 to compare the composition of species arriving at ports in these regions. Collectively, 8,716 insect species were intercepted in these regions over the last 25 yr, with the combined international data set comprising 1,899,573 interception events, of which 863,972 were identified to species level. Rarefaction analysis indicated that interceptions comprise only a small fraction of species present in invasion pathways. Despite differences in inspection methodologies, as well as differences in the composition of import source regions and imported commodities, we found strong positive correlations in species interception frequencies between regions, particularly within the Hemiptera and Thysanoptera. There were also significant differences in species frequencies among insects intercepted in different regions. Nevertheless, integrating interception data among multiple regions would be valuable for estimating invasion risks for insect species with high likelihoods of introduction as well as for identifying rare but potentially damaging species.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract Global biodiversity is under substantial threat due to biological invasions, a problem exacerbated by climate change. Such invasions have detrimental effects on the environment, economy, and ...human health, resulting in significant financial burdens. Recently, understanding these challenges has become a highlighted priority within the scientific community. This study focuses on the evaluation of Schinus terebinthifolia, native to South America, and its invasive spread into North and Central America, which has resulted in wide distribution and considerable impact. The primary objectives of this study include analyzing the potential distribution of the species under current and future climate scenarios, identifying the areas where its climatic niche is changing. Data collection encompassed a vast dataset of over 30,000 occurrence records of this species, from the following databases: (1) The Global Biodiversity Information Facility provided 22,163 records (GBIF), (2) The virtual Herbarium Reflora contributed 1,438 records, and NeoTropTree made available 6,591 records. Following a rigorous filtering process, 992 occurrences were considered for modeling. In this process, we utilized climate data and climate projections, employing various algorithms, with an emphasis on the consensus model methodology. The research results reveal a clear trend of reduced habitat suitability for S. terebinthifolia, especially under scenarios of high global warming. This accentuates the urgency of implementing emission control measures and mitigation strategies. Additionally, the study underscores the crucial importance of continuous monitoring, as well as actions for controlling and restoring affected ecosystems. The significant role played by S. terebinthifolia in both its native and invaded areas highlights the need for comprehensive management approaches. In the face of climate change and biodiversity threats, this study provides insightful observations on the dynamics of biological invasions. Success in addressing these issues relies on close cooperation between the scientific community, policymakers, land managers, and local communities. This collaboration is essential for guiding and conducting conservation and biodiversity management efforts in an ever-evolving world.
Resumo A biodiversidade global encontra-se sob ameaça substancial devido às invasões biológicas, um problema agravado pelas mudanças climáticas. Tais invasões têm efeitos prejudiciais sobre o meio ambiente, economia e saúde humana, resultando em encargos financeiros significativos. Recentemente, a compreensão desses desafios se tornou prioridade destacada na comunidade científica. Este estudo se concentra na avaliação do Schinus terebinthifolia, nativa da América do Sul, e sua disseminação invasiva para a América do Norte e Central, o que resultou em ampla distribuição e impacto considerável. Os principais objetivos deste estudo consistem em analisar a distribuição potencial da espécie sob cenários climáticos atuais e futuros, identificando as áreas onde seu nicho climático está se alterando. A coleta abrangeu um vasto conjunto de mais de 30.000 registros de ocorrências da espécie, nas bases de bados (1) Global Biodiversity Information Facility com 22.163 registros (GBIF), (2) O Herbário virtual Reflora com 1.438 registros e o NeoTropTree com 6.591 registros e após um processo de filtragem, 992 ocorrências foram consideradas para modelagem. Nesse processo, empregamos dados climáticos e projeções climáticas, recorrendo a diversos algoritmos, com destaque para a metodologia do modelo de consenso. Os resultados da pesquisa revelam uma clara tendência de redução na adequação do habitat da S. terebinthifolia, especialmente sob cenários de elevado aquecimento global. Isso acentua a urgência da implementação de medidas de controle de emissões e estratégias de mitigação. Adicionalmente, o estudo ressalta a importância crucial da vigilância contínua, bem como das ações de controle e restauração de ecossistemas afetados. O papel relevante desempenhado por S. terebinthifolia em suas áreas nativas e invadidas chama a atenção para a necessidade de adotar abordagens de manejo abrangentes. Diante do cenário de mudanças climáticas e das ameaças à biodiversidade, este estudo contribui com perspicazes observações sobre a dinâmica das invasões biológicas. O sucesso na abordagem dessas questões depende de uma cooperação estreita entre a comunidade científica, legisladores, gestores de terras e as comunidades locais. Essa colaboração é essencial para orientar e conduzir os esforços de conservação e gestão da biodiversidade em um mundo em constante evolução.
The economic and environmental threats posed by non-native forest insects are ever increasing with the continuing globalization of trade and travel; thus, the need for mitigation through effective ...biosecurity is greater than ever. However, despite decades of research and implementation of preborder, border, and postborder preventative measures, insect invasions continue to occur, with no evidence of saturation, and are even predicted to accelerate. In this article, we review biosecurity measures used to mitigate the arrival, establishment, spread, and impacts of non-native forest insects and possible impediments to the successful implementation of these measures. Biosecurity successes are likely under-recognized because they are difficult to detect and quantify, whereas failures are more evident in the continued establishment of additional non-native species. There are limitations in existing biosecurity systems at global and country scales (for example, inspecting all imports is impossible, no phytosanitary measures are perfect, knownunknowns cannot be regulated against, and noncompliance is an ongoing problem). Biosecurity should be a shared responsibility across countries, governments, stakeholders, and individuals.
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