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1.
    
Aim To determine relative effects of habitat type, climate and spatial pattern on species richness and composition of native and alien plant assemblages in central European cities. Location Central Europe, Belgium and the Netherlands. Methods The diversity of native and alien flora was analysed in 32 cities. In each city, plant species were recorded in seven 1‐ha plots that represented seven urban habitat types with specific disturbance regimes. Plants were classified into native species, archaeophytes (introduced before ad 1500) and neophytes (introduced later). Two sets of explanatory variables were obtained for each city: climatic data and all‐scale spatial variables generated by analysis of principal coordinates of neighbour matrices. For each group of species, the effect of habitat type, climate and spatial variables on variation in species composition was determined by variation partitioning. Responses of individual plant species to climatic variables were tested using a set of binomial regression models. Effects of climatic variables on the proportion of alien species were determined by linear regression. Results In all cities, 562 native plant species, 188 archaeophytes and 386 neophytes were recorded. Proportions of alien species varied among urban habitats. The proportion of native species decreased with increasing range and mean annual temperature, and increased with increasing precipitation. In contrast, proportions of archaeophytes and neophytes increased with mean annual temperature. However, spatial pattern explained a larger proportion of variation in species composition of the urban flora than climate. Archaeophytes were more uniformly distributed across the studied cities than the native species and neophytes. Urban habitats rich in native species also tended to be rich in archaeophytes and neophytes. Main conclusions Species richness and composition of central European urban floras are significantly affected by urban habitat types, climate and spatial pattern. Native species, archaeophytes and neophytes differ in their response to these factors.  相似文献   

2.
    
Manipulating plant order of arrival, a process that creates priority effects, may be an unexplored powerful tool to hinder the establishment of invasive non‐native plants in sites under restoration. Knowledge and experimental studies on priority effects in the neotropics are scarce. Here, we propose a research agenda that investigates whether manipulating plant order of arrival can create priority effects in the neotropics, and if this strategy can be used to avoid the spread of undesired species in restoration projects. We also describe our view on expanding existing knowledge on priority effects to the neotropics and identifying key questions for future research.  相似文献   

3.
    
  • 1 Throughout Europe, the range of many deer species is expanding. We provide current distribution maps for red deer Cervus elaphus, sika Cervus nippon, fallow deer Dama dama and muntjac deer Muntiacus sp. in Ireland, and estimates of range expansion rates for red deer, sika and fallow deer.
  • 2 There was a considerable expansion in the ranges of red deer, sika and fallow deer between 1978 and 2008. The compound annual rate of expansion was 7% for red deer, 5% for sika and 3% for fallow deer. The total range increase was 565% for red deer, 353% for sika and 174% for fallow deer. The potential implications of these expansions are discussed.
  • 3 There are unknown numbers of red‐sika hybrid deer in some parts of Ireland. Range expansion is likely to lead to further hybridizations with implications for the genetic integrity of deer stocks.
  • 4 Sightings of free‐roaming muntjac deer were first recorded in 2007. The distribution of confirmed sightings of single and multiple animals in the eastern region of Ireland suggests multiple releases.
  • 5 Deer are already impacting on both the economic and biodiversity values of habitats in Ireland, where, at present, no sustainable deer management policy exists.
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4.
    
  1. We report the results of the first systematic assessment of global patterns and research priorities emerging in the field of rodent pest management. We carried out an extensive literature review targeted towards identifying the most relevant rodent pests, their impacts and the most common methods used to control them.
  2. We identified three disproportionally important pest species that are characterized by severe, generalist and geographically widespread impacts: the black rat Rattus rattus, the Norway rat Rattus norvegicus and the house mouse Mus musculus. Overall, only 7% of known rodent species may be considered pests. Scansorial (i.e. terrestrial and semi‐arboreal) and fossorial species are generally important as pests, while aquatic and arboreal species have only specific impacts.
  3. Impacts of rodent pests on arable crops were studied most, followed by impacts on ecosystems. Studies on arable crops were typical in countries with low net income and health expenditure, while the opposite was observed for studies on ecosystems. Poisons were the most commonly used control method, followed by traps and habitat management. The need to control rodent species is expanding, especially to protect ecosystems and public health. Unlike in other fields of pest management (e.g. insect control), in rodent control we are approaching new problems with old solutions; control strategies and methods have not kept pace with emerging impacts.
  4. The need to control a rodent pest species is higher when it is non‐native than within its original geographical range. The impact of a rodent species in its native range is a good predictor of the impact it may have in areas of introduction.
  5. Our review will contribute towards guiding researchers and stakeholders to focus research efforts and investments on a subset of species, and on new, less hazardous control techniques.
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5.
    
  1. Two dominant drivers of species distributions are climate and habitat, both of which are changing rapidly. Understanding the relative importance of variables that can control distributions is critical, especially for invasive species that may spread rapidly and have strong effects on ecosystems.
  2. Here, we examine the relative importance of climate and habitat variables in controlling the distribution of the widespread invasive freshwater clam Corbicula fluminea, and we model its future distribution under a suite of climate scenarios using logistic regression and maximum entropy modelling (MaxEnt).
  3. Logistic regression identified climate variables as more important than habitat variables in controlling Corbicula distribution. MaxEnt modelling predicted Corbicula's range expansion westward and northward to occupy half of the contiguous United States. By 2080, Corbicula's potential range will expand 25–32%, with more than half of the continental United States being climatically suitable.
  4. Our combination of multiple approaches has revealed the importance of climate over habitat in controlling Corbicula's distribution and validates the climate‐only MaxEnt model, which can readily examine the consequences of future climate projections.
  5. Given the strong influence of climate variables on Corbicula's distribution, as well as Corbicula's ability to disperse quickly and over long distances, Corbicula is poised to expand into New England and the northern Midwest of the United States. Thus, the direct effects of climate change will probably be compounded by the addition of Corbicula and its own influences on ecosystem function.
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6.
    
  1. Rodents are traded as pet species, a practice that frequently results in new introduced populations. This is particularly true for tree squirrels where, often, only a few founders can establish viable colonies.
  2. Here, we review the worldwide introductions, ecology and impacts of two tree squirrel species, Callosciurus erythraeus and Callosciurus finlaysonii, and discuss the elements of a strategy to reduce squirrel introductions and settlements.
  3. C. erythraeus has established viable populations in Argentina, France, The Netherlands, Hong Kong and Japan. An introduction to Belgium may have been stopped successfully. C. finlaysonii has been introduced to Italy, Singapore and Japan. After 1950, the mean number of introduction events was one every two years.
  4. The most evident damage caused by these species is bark stripping that can be severe and may significantly impact trees and timber plantations. Data on negative impacts to native species are reported but have not yet been formally quantified. Both squirrel species carried with them parasites from the native range into the new habitats, leading to the introduction of other species.
  5. The ability of tree squirrels to establish themselves successfully, often from only a few founders, combined with their human appeal make them high‐risk species, and the pet trade should be considered as a high‐risk pathway for new introductions. A proactive approach to preventing new introductions should therefore include trade restrictions, and should be combined with public education initiatives at national and European scales.
  6. Tree squirrels represent an ‘alien species conundrum’. Experience from the UK and Italy has shown that if action is delayed until introductions are recognized as a problem, it is generally too late to control populations effectively, due to logistic, legal or economic reasons, or due to lack of public support. In the case of new populations, a rapid response mechanism is therefore critical. Once established, populations may become invasive and difficult or impossible to control.
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7.
    
Risk analyses are predictive systems designed to detect the risk of invasion by non‐native species. Although eucalypts are often considered moderately invasive given the extent of cultivation on a global scale, some species are widely recognized as invasive for transforming and impacting natural areas in several countries. These problems may be due to propagule pressure derived from human interest in forest production and aesthetic values. Risk analyses were carried out for 16 eucalypt species cultivated in Brazil using a protocol adapted from an Australian model to Brazilian conditions. The species were: Corymbia citriodora, Corymbia maculata, Corymbia torelliana, Eucalyptus benthamii, Eucalyptus brassiana, Eucalyptus camaldulensis, Eucalyptus cloeziana, Eucalyptus dunnii, Eucalyptus globulus, Eucalyptus grandis, Eucalyptus pellita, Eucalyptus robusta, Eucalyptus saligna, Eucalyptus tereticornis, Eucalyptus urophylla and Eucalyptus viminalis. Results indicate high risk for seven species, moderate risk for eight species and low risk for one species. The only low risk species is E. dunnii, while the highest risk scores refer to C. torelliana, E. tereticornis and E. grandis. These results are consistent with the history of invasion of the species around the world and should be considered for plantations especially when investment capacity to prevent and permanently control spread is low or not associated with forest certification standards. Risk analysis is a valid tool for discriminating between species and making decisions on species to be introduced or cultivated. The results of this study show that there are many species that can be cultivated without incurring biological invasions.  相似文献   

8.
辽宁省是东北地区重要的“菜篮子”生产基地。蔬菜易受到潜叶蝇的为害,导致蔬菜产业的健康发展受到威胁。为了更好防控蔬菜上的潜叶蝇,本研究对辽宁省潜叶蝇和寄生蜂进行本底资源调查。以辽宁省潜叶蝇及其天敌寄生蜂的种类和多样性为切入点进行田间调查,采用随机取样法,于2016-2020年调查辽宁省蔬菜、花卉以及杂草上潜叶蝇及其寄生蜂的种类和多样性,并基于形态特征与COI基因序列对潜叶蝇和寄生蜂的种类进行鉴定。结果显示,辽宁省共鉴定出5种潜叶蝇,包括本地种豌豆彩潜蝇Phytomyza horticola和葱斑潜蝇Liriomyza chinensis,入侵种美洲斑潜蝇L. sativae、三叶草斑潜蝇L. trifolii和番茄斑潜蝇L. bryoniae;其中发生最为优势的种类为豌豆彩潜蝇,其嗜好十字花科和菊科植物;寄主谱最广的是美洲斑潜蝇,发现危害7科17种植物。共发现潜叶蝇的寄生蜂41种,从发生数量来看,以姬小蜂科最多(7 816头,占比78.84%),其次是金小蜂科(1 533头,占比15.46%)、茧蜂科(549头,占比5.54%)和瘿蜂科(16头,占比0.16%);姬小蜂科的多样性指数和丰富度指数均最高,瘿蜂科均匀度指数最高;豌豆潜蝇姬小蜂Diglyphus isaea(4 385头)是优势种,占寄生蜂总数的44.23%。本研究填补了辽宁省潜叶蝇及其天敌寄生蜂的种类及多度调查的空白,为该省份潜叶蝇的防治和天敌寄生蜂的深入研究奠定了理论基础,同时建议加强对辽宁省的豌豆彩潜蝇和美洲斑潜蝇的防治,发挥当地优势寄生蜂如豌豆潜蝇姬小蜂对潜叶蝇的生物防控作用。  相似文献   

9.
    
  1. A long‐standing goal of invasion biology is to identify factors driving highly variable impacts of non‐native species. Although hypotheses exist that emphasize the role of evolutionary history (e.g., enemy release hypothesis & defense‐free space hypothesis), predicting the impact of non‐native herbivorous insects has eluded scientists for over a century.
  2. Using a census of all 58 non‐native conifer‐specialist insects in North America, we quantified the contribution of over 25 factors that could affect the impact they have on their novel hosts, including insect traits (fecundity, voltinism, native range, etc.), host traits (shade tolerance, growth rate, wood density, etc.), and evolutionary relationships (between native and novel hosts and insects).
  3. We discovered that divergence times between native and novel hosts, the shade and drought tolerance of the novel host, and the presence of a coevolved congener on a shared host, were more predictive of impact than the traits of the invading insect. These factors built upon each other to strengthen our ability to predict the risk of a non‐native insect becoming invasive. This research is the first to empirically support historically assumed hypotheses about the importance of evolutionary history as a major driver of impact of non‐native herbivorous insects.
  4. Our novel, integrated model predicts whether a non‐native insect not yet present in North America will have a one in 6.5 to a one in 2,858 chance of causing widespread mortality of a conifer species if established (R2 = 0.91)
  5. Synthesis and applications. With this advancement, the risk to other conifer host species and regions can be assessed, and regulatory and pest management efforts can be more efficiently prioritized.
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10.
    
The purpose of this study was to develop a model to predict electroshock‐induced mortality in embryos of freshwater fishes. Herein, electroshock‐induced mortality was evaluated for sauger Sander canadensis and rainbow trout Oncorhynchus mykiss, and results were combined with published results obtained for eight other species in studies that used consistent methodology. The model was based on embryo diameter (1·1–4·1 mm among species), the most sensitive stage of embryonic development (near completion of epiboly for all species), and mortality (to hatching or eyed stage) after exposure to a homogeneous electric field [direct current (DC) or 60 Hz pulsed DC (PDC)]. Embryo diameter was positively related to electroshock‐induced mortality for DC (P < 0·001) and 60 Hz PDC (P < 0·05). Results suggested that vulnerability to electroshock‐induced mortality was related to physical characteristics (i.e. size) of embryos rather than species differences, and indicated that prediction of vulnerability in untested species is possible. This is particularly important for protection of endangered species, and those species with larger embryo sizes may be at most risk from electroshock. Conversely, results also suggested that it may be possible to assist in removal of invasive non‐native fish species with large embryo diameters (e.g. O. mykiss) by application of electroshock to target and kill embryos of these species in some freshwater habitats.  相似文献   

11.
    
Aim To determine whether invasive and locally abundant non‐native species have a more homogenizing effect on plant communities than non‐invasive and less abundant non‐native species. Location California and Florida counties, conservation areas in the USA, and eight US cities. Methods Species lists among counties, conservation areas and cities were compared to see whether invasive and abundant non‐native species increased the Jaccard index of similarity between localities beyond any increases caused by non‐invasive and less abundant non‐native species. Results For all comparisons, we found that invasive non‐native species have a significantly greater homogenizing effect than non‐invasive non‐native species. For the US conservation areas, we found that locally abundant invasive species tend to be more widespread and more widely shared than less abundant invasive species. There is also a positive relationship between homogenization by invasive species and the magnitude of human disturbance. Main conclusions Invasive non‐native species tend to be disproportionately shared among communities relative to non‐invasive non‐native species. This effect is enhanced by human disturbance, as measured by the ratio of non‐native to native species. There is a synergism between abundance and geographical range which enhances the homogenizing effects of abundant species. Invasive species, with wide ecological niches, are more widely shared among communities and more locally abundant. Abundant invasive species are thus more spatially homogenizing, and more ecologically dominant (functionally homogenizing). Also, ‘perceived homogenization’ is probably greater than homogenization measured by the increase in shared species. The abundant species typically seen by the casual observer in a biological community are probably more commonly shared between communities than less common species. Studies that lack abundance data and measure homogenization only on the basis of shared species, which includes most homogenization studies to date, probably underestimate the homogenizing impacts of non‐native species as perceived by people.  相似文献   

12.
    
  1. The North American oak lace bug feeds on leaves of ‘white oaks” in its native range. In Europe, it was first discovered in northern Italy in 2000. In recent years, it has subsequently spread rapidly and population outbreaks have been observed in several European countries. In the present study, we summarize the steps of its expansion.
  2. To predict its potential host range, we checked 48 oak species in 20 sentinel gardens in seven countries between 2013 and 2018.
  3. In total, 27 oak species were recorded as suitable hosts; 13 of them are globally new ones, 23 out of the 29 in section Quercus (~ white oaks, an intrageneric taxonomic unit within genus Quercus), including Asian oaks, native to Japan, Korea and China, and four out of five in section Cerris (another intrageneric unit of the same genus), were accepted as hosts. None of the species in section Lobatae (red oaks) or in the Ilex group was accepted.
  4. Host records were also collected in forest stands of 10 countries. We found 11 oak species that were infested. Outbreak populations were most commonly found on Quercus robur, Quercus frainetto, Quercus petraea and Quercus cerris, comprising widespread and outstandingly important oaks species in Europe.
  5. Based on our findings, we conclude that suitable hosts for oak lace bug are present in most of Europe and Asia. This means that a lack of hosts will likely not restrict further range expansion.
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13.
14.
    
1. Harmonia axyridis was first recorded in Britain in 2004. Two subsequent earlier records were received from 2003. 2. The UK Ladybird Survey, a citizen science initiative involving online recording, was launched in 2005 to encourage people across Britain to track the spread of H. axyridis. Tens of thousands of people have provided records of H. axyridis and other species of ladybirds, creating an invaluable dataset for large‐scale and long‐term research. Declines in the distribution of seven (of eight assessed) native species of ladybird have been demonstrated, and correlated with the arrival of H. axyridis, using the records collated through the UK Ladybird Survey. 3. Experimental research and field surveys have also contributed to our understanding of the ecology of H. axyridis and particularly the process of invasion. Harmonia axyridis arrived in Britain through dispersal and introduction events from regions in which it was deliberately released as a biological control agent. The rapid spread of this species has been attributed to its high natural dispersal capability by means of both flight and anthropogenic transport. A number of factors have contributed to the successful establishment and indeed dominance of this polymorphic species within aphidophagous guilds, including high reproductive capacity, intra‐guild predation, eurytopic nature, high resistance to natural enemies within the invaded range, and potentially phenotypic plasticity. 4. The global invasion by H. axyridis and subsequent research on this species has contributed to the general understanding of biological invasions.  相似文献   

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16.
    
Lonicera maackii (Amur honeysuckle) is a non‐native species that has invaded forest stands throughout the eastern United States. This research examined using aerially applied glyphosate in autumn 2013 to control L. maackii in oak‐hickory forest stands in Missouri, U.S.A. We targeted the spraying time period when L. maackii was still green and most native plants were dormant. Across treatment units, the mean difference in L. maackii stem density significantly declined (p = 0.004) by 5.4 stems per plot from spring 2013 to summer 2014 when compared to control units which increased by 1.8 stems per plot. Treated units with a high initial infestation level of L. maackii (>50% cover) had a significant (p = 0.004) decline in the mean difference in L. maackii cover of ?50.0% per plot between spring 2013 and summer 2014 compared to an average increase of 9.2% in the controls. Similar results were found for treated units with a low initial infestation level of L. maackii (10–50% cover). Mortality of native overstory and understory trees post‐treatment was negligible. In the ground layer of forest stands with a low initial L. maackii infestation level, native non‐spray‐sensitive forb cover per plot significantly increased (p = 0.023) relative to controls between summer 2013 and summer 2014 while native spray‐sensitive species cover significantly decreased (p = 0.021) during the same period. These results suggest that an aerial application of glyphosate can provide an L. maackii control option, but with trade‐offs in compositional shifts in the native ground‐layer vegetation.  相似文献   

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The biotic resistance hypothesis predicts that diverse native communities are more resistant to invasion. However, past studies vary in their support for this hypothesis due to an apparent contradiction between experimental studies, which support biotic resistance, and observational studies, which find that native and non‐native species richness are positively related at broad scales (small‐scale studies are more variable). Here, we present a novel analysis of the biotic resistance hypothesis using 24 456 observations of plant richness spanning four community types and seven ecoregions of the United States. Non‐native plant occurrence was negatively related to native plant richness across all community types and ecoregions, although the strength of biotic resistance varied across different ecological, anthropogenic and climatic contexts. Our results strongly support the biotic resistance hypothesis, thus reconciling differences between experimental and observational studies and providing evidence for the shared benefits between invasive species management and native biodiversity conservation.  相似文献   

20.
【目的】明确严重危害甘肃省白银地区作物的潜叶蝇及天敌寄生蜂的多样性和种群组成。【方法】采用五点取样法田间调查潜叶蝇危害的蔬菜、花卉、杂草并采样,室内对潜叶蝇及其寄生蜂进行形态鉴定和分子鉴定。【结果】在2016-2020年在甘肃白银地区采集的样本中发现6种常见潜叶蝇,包括本地种豌豆彩潜蝇Chromatomyia horticola和葱斑潜蝇Liriomyza chinensis,入侵种南美斑潜蝇L. huidobrensis、三叶草斑潜蝇L. trifolii、番茄斑潜蝇L. bryoniae和美洲斑潜蝇L. sativae。其中,豌豆彩潜蝇为优势种,可危害多科寄主植物;葱斑潜蝇仅在大葱上发现危害;南美斑潜蝇在温室内的蔬菜上发生严重;三叶草斑潜蝇首次在白银市发现;番茄斑潜蝇与美洲斑潜蝇的危害相对较轻。此外,调查的潜叶蝇寄生蜂包括3科12属24种,优势种包括豌豆潜蝇姬小蜂Diglyphus isaea、芙新姬小蜂Neochrysocharis formosa、万氏潜蝇姬小蜂D. wani和西伯利亚离颚茧蜂Dacnusa sibirica。【结论】一方面白银市应加强监测和预警入侵性潜叶蝇的发生,另一方面白银市潜叶蝇的天敌寄生蜂种类丰富,对田间主要危害的潜叶蝇可能发挥着重要的自然防控作用,建议保护利用本地寄生蜂天敌。  相似文献   

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