米草属植物入侵的生态后果及管理对策

生物入侵是全球变化的重要组成部分,可能对入侵地造成严重的经济和生态后果,所以评价外来种入侵的生态后果是入侵生态学研究的核心问题之一。本文以米草属(Spartina)植物为例,综述了其对入侵地区自然环境、生物种群、群落和生态系统的影响;结合国际上对米草属入侵种的管理策略,讨论了我国米草属植物管理中的一些重要问题。     

Drivers of future alien species impacts: An expert‐based assessment

Understanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio‐economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid‐21st century. Based on responses from 36 experts in biological invasions, moderate (20%–30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions—transport, climate change and socio‐economic change—were predicted to significantly affect future impacts of alien species on biodiversity even under a best‐case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best‐case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post‐2020 Framework of the Convention on Biological Diversity.     

火与外来植物相互关系的研究进展

入侵种对本地的生态系统和生物多样性均有不良的影响,严重的会造成物种的灭绝和生态系统的崩溃,这已在全球范围引起广泛关注.在植物外来种与火生态因子的作用研究中发现,火与外来种的关系随物种生物学特性、火作用的时间、频度、强度不同而不同,火有时会有效地抑制外来种的生长和入侵,有时会促进一些外来种的生长和入侵.反之,一些外来种会对火的产生起到积极的作用,一些外来种又会抑制火的发生.火作为控制入侵种的一种方法,经科学地运用,可对某些入侵种起到有效的控制作用.     

Dispersal in the course of an invasion

Invasive species receive attention as manifestations of global ecological change and because of the effects that they may have on other organisms. They are commonly discussed in the context of the ecological perturbations or the human activities that permitted the invasion. There is also evidence, that there is an intrinsic component to biological invasions in that evolutionary changes of the invaders themselves can facilitate or limit invasions (Lee 2002; Urban et al. 2007; Van Bocxlaer et al. 2010). Hence, teasing apart whether environmental change or changes of the organism foster invasions is an interesting field of research. Ample evidence for plants and animals documents that ecological change and human activities trigger range expansions and invasions, but questions regarding evolutionary change of invaders remain less explored although there are several reasons to believe it matters. Firstly, rapid evolutionary change is possible in time-frames relevant for contemporary biological invasions(Hendry et al. 2007). Furthermore, population genetic modelling suggests that there are circumstances where the range expansion and colonization of empty spaces in the course of an invasion can induce evolutionary change in a way that is specific to invaders: the process of repeated founding out of marginal populations in the course of a range expansion can shift allele frequencies and has been referred to as allele surfing, which not only affects neutral genetic variance, but also fitness relevant traits (Klopfstein et al. 2006; Travis et al. 2007; Burton & Travis 2008). Importantly, this process poses a null model for evolutionary inference in invasive populations. It predicts conspicuous allele frequency changes in an expanding metapopulation unless migration homogenizes the gene pool. Despite this relevance, ideas about allele surfing rely heavily on modelling although some experimental evidence comes from studies that document the segregation of genetic variants in growing plaques of bacteria (Hallatschek et al. 2007). To date, little empirical data is available that would reveal the migration processes that affect the establishment of gene pools at invasion fronts in natural systems. This aspect sets the study of Bronnenhuber et al. (2011) apart. They quantify migration behind the expansion front of an invading fish and thus provide important baseline data for the interpretation of the emerging patterns of genetic differentiation.     

Introduced species: A significant component of human-caused global change

Biological invasions are a widespread and significant component of human-caused global environmental change. The extent of invasions of oceanic islands, and their consequences for native biological diversity, have long been recognized. However, invasions of continental regions also are substantial. For example, more than 2,000 species of alien plants are established in the continental United States. These invasions represent a human-caused breakdown of the regional distinctiveness of Earth's flora and fauna—a substantial global change in and of itself. Moreover, there are well- documented examples of invading species that degrade human health and wealth, alter the structure and functioning of otherwise undisturbed ecosystems, and/or threaten native biological diversity. Invasions also interact synergistically with other components of global change. notably land use change. People and institutions working to understand, prevent, and control invasions are carrying out some of the most important—and potentially most effective—work on global environmental change.     

The risk of invasion by angiosperms peaks at intermediate levels of human influence

Biological invasions are a growing threat to biodiversity. The control and eradication of exotic species established in earnest are of limited success despite high financial investments. Anticipating biological invasions based on species’ suitabilities is a cost-effective strategy given it helps identifying areas where exotic species can prosper, which can then translate in improving management and conservation efforts. Based on information from 191 invasive angiosperm species worldwide, we used ecological niche models to identify areas at high risk of invasion (cumulative predicted distribution of invasive species) in Mexico. Further, we explored the importance of bioclimatic and human influence variables as drivers of the distribution of invasive species and analyzed the status of the currently recognized priority conservation sites in Mexico. We found that areas with intermediate human activity scores had a high risk of invasion. Additionally, we found that many of the current priority conservation sites in Mexico had a high risk of invasion. Our findings contribute to disentangling the factors that drive environment susceptibility to invasions and urge management strategies to minimize the impacts of biological invasions in priority conservation sites.     

生物入侵的危害与防治对策

生物入侵是一个世界范围的生态学现象。入侵种通过竞争、捕食、改变生境和传播疾病等方式对本地种及其系统产生影响。生物入侵的危害表现为：造成巨大的经济损失,仅美国每年因外来种入侵造成的经济损失近1370亿美元;威胁到人类的健康和生存。成千上万的人被外来种传染疾病以致死亡;引起严重的社会恐慌和动荡,人们寝食不安;改变了生态系统的结构和功能,全球自然灾害频频爆发;导致生物多样性的急剧下降,威胁到子孙后代的生存和发展。防治生物入侵有3条途径：实行全面检疫,阻止外来种的偶然入侵;采取全面的生态评估和监测,防范引进品种的入侵灾难;对已入侵的外来种采用机械法、化学法和生物防治法进行根除和控制,应用生物防治法、筛选天敌和对其进行危害评估时要特别慎重。     

丛枝菌根真菌在外来植物入侵演替中的作用与机制

外来植物入侵不仅是环境、经济和社会问题,也是一个生理学和生态学问题,尤其是入侵植物与本地植物、入侵植物和本地土壤生物之间的相互作用决定外来植物入侵程度。丛枝菌根真菌（AMF）作为土壤中一类极为重要的功能生物,在外来植物入侵演替过程中发挥多种不同作用。文章系统总结了AMF对入侵植物个体和群体的影响,入侵植物与本地植物竞争中AMF发挥的促进和抑制作用;探讨了AMF与入侵植物的相互作用关系,以及环境因子对AMF一入侵植物关系的影响：对AMF在外来植物入侵演替中的作用机制进行了讨论。旨在为探索控制生物入侵的新途径、为我国开展外来植物入侵研究与防控实践提供新思路。     

海洋外来物种入侵生态学研究

海洋外来物种入侵已成为最为严重的全球性环境问题之一。海洋生态系统类型多样、环境复杂,其生物入侵的监测、控制与管理难度相对较大。我国对陆地外来生物的入侵已开展了较为深入的研究,但对于海洋外来生物的入侵研究仍处于起步阶段,对其入侵监测、入侵机制、入侵危害的程度以及防治等问题缺乏基础数据。本文在分析国内外海洋外来生物入侵现状的基础上,概述其入侵生态学研究形势及相关成果,包括海洋外来物种的入侵途径、入侵过程、入侵生态效应以及全球变化对入侵的影响等。海洋外来生物的入侵可能对海洋生态系统造成直接或间接的影响,如种间竞争破坏生态环境、与土著种杂交造成遗传污染、病原生物及有毒藻类导致海洋生态灾害加剧等。此外,从政策和法规、入侵风险评估、监测和公共宣传教育、生物信息系统和有效管理机制等方面提出对我国海洋外来物种入侵的防治策略。本研究为我国海洋外来物种的进一步研究提供了参考。     

Logging,exotic plant invasions,and native plant reassembly in a lowland tropical rain forest

Habitat modification and biological invasions are key drivers of global environmental change. However, the extent and impact of exotic plant invasions in modified tropical landscapes remain poorly understood. We examined whether logging drives exotic plant invasions and whether their combined influences alter understory plant community composition in lowland rain forests in Borneo. We tested the relationship between understory communities and local‐ and landscape‐scale logging intensity, using leaf area index (LAI) and aboveground biomass (AGB) data from 192 plots across a logging‐intensity gradient from primary to repeatedly logged forests. Overall, we found relatively low levels of exotic plant invasions, despite an intensive logging history. Exotic species were more speciose, had greater cover, and more biomass in sites with more local‐scale canopy loss. Surprisingly, though, exotic species invasion was not related to either landscape‐scale canopy loss or road configuration. Moreover, logging and invasion did not seem to be acting synergistically on native plant composition, except that seedlings of the canopy‐dominant Dipterocarpaceae family were less abundant in areas with higher exotic plant biomass. Current low levels of invasion, and limited association with native understory community change, suggest there is a window of opportunity to manage invasive impacts. We caution about potential lag effects and the possibly severe negative impacts of exotic plant invasions on the long‐term quality of tropical forest, particularly where agricultural plantations function as permanent seed sources for recurrent dispersal along logging roads. We therefore urge prioritization of strategic management plans to counter the growing threat of exotic plant invasions in modified tropical landscapes.     

Conceptualising the interactive effects of climate change and biological invasions on subarctic freshwater fish

Climate change and species invasions represent key threats to global biodiversity. Subarctic freshwaters are sentinels for understanding both stressors because the effects of climate change are disproportionately strong at high latitudes and invasion of temperate species is prevalent. Here, we summarize the environmental effects of climate change and illustrate the ecological responses of freshwater fishes to these effects, spanning individual, population, community and ecosystem levels. Climate change is modifying hydrological cycles across atmospheric, terrestrial and aquatic components of subarctic ecosystems, causing increases in ambient water temperature and nutrient availability. These changes affect the individual behavior, habitat use, growth and metabolism, alter population spawning and recruitment dynamics, leading to changes in species abundance and distribution, modify food web structure, trophic interactions and energy flow within communities and change the sources, quantity and quality of energy and nutrients in ecosystems. Increases in temperature and its variability in aquatic environments underpin many ecological responses; however, altered hydrological regimes, increasing nutrient inputs and shortened ice cover are also important drivers of climate change effects and likely contribute to context‐dependent responses. Species invasions are a complex aspect of the ecology of climate change because the phenomena of invasion are both an effect and a driver of the ecological consequences of climate change. Using subarctic freshwaters as an example, we illustrate how climate change can alter three distinct aspects of species invasions: (1) the vulnerability of ecosystems to be invaded, (2) the potential for species to spread and invade new habitats, and (3) the subsequent ecological effects of invaders. We identify three fundamental knowledge gaps focused on the need to determine (1) how environmental and landscape characteristics influence the ecological impact of climate change, (2) the separate and combined effects of climate and non‐native invading species and (3) the underlying ecological processes or mechanisms responsible for changes in patterns of biodiversity.     

Micronutrient input into a mangrove ecosystem in Jobos Bay,Puerto Rico, by the exotic green iguana Iguana iguana

Biological invasions are an important and growing component of global environmental change (Vitousek et al., 1996). Hundreds of billions of dollars are lost each year to invasive species damage and management(Pimentel et al., 2001).     

气候变化背景下生物入侵研究态势的文献计量分析

生物入侵严重威胁生物多样性与生态系统健康,对全球环境、经济造成极大损失,而快速的气候变化显著影响外来生物的扩散和入侵进程。探讨气候变化背景下生物入侵研究态势能够从宏观上把握该领域的国际研究现状与热点,为深入理解外来种入侵机制和制定合理的防治策略提供参考。该文基于最近27 a间(1990—2016年)科学文献数据库Web of Science中科学引文索引扩展版(SCI-E)数据,利用TDA等统计工具对气候变化下生物入侵方面的研究进行了文献计量分析。结果表明:27 a间共发表论文1 736篇,论文数量整体保持增长态势,2009年开始进入快速发展阶段;该领域的研究涉及环境科学与生态学、生物多样性保护、植物学等多个学科;澳大利亚莫纳什大学Chown SL教授发文量最高(35篇);美国的总发文量(708篇)和高被引、高影响因子论文数量均居世界首位;发文量最多的研究机构是加利福尼亚大学(93篇),中国科学院发文量居世界第10位(27篇);Biological Invasions是刊文量最大的学术杂志;物种分布模型、生物多样性、全球变暖、风险评估等是近年来该领域的研究热点;中国共发表论文52篇,中国科学院是国内最大的发文机构,其中,动物研究所、武汉植物园、植物研究所的发文量居中科院科研系统前三名;中国在气候变化下生物入侵领域的高被引、高影响因子论文数量及国际合作强度亟待提升。未来需重点关注气候变化下生物入侵的预测与风险评估、生物入侵与生物多样性关系、入侵物种的系统进化、入侵生态系统的多营养级关系、海洋生物入侵、生物入侵与人类健康等问题。     

Evolutionary responses of native plants to novel community members

Both ecological and evolutionary processes can influence community assembly and stability, and native community members may respond both ecologically and evolutionarily as additional species enter established communities. Biological invasions provide a unique opportunity to examine these responses of native community members to novel species additions. Here, I use reciprocal transplant experiments among naturally invaded and uninvaded environments, along with experimental removals of exotic species, to determine whether exotic plant competitors and exotic insect herbivores evoke evolutionary changes in native plants. Specifically, I address whether the common native plant species Lotus wrangelianus has responded evolutionarily to a series of biological invasions by adapting to the presence of the exotic plant Medicago polymorpha and the exotic insect herbivore Hypera brunneipennis. Despite differences in selection regimes between invaded and uninvaded environments and the presence of genetic variation for traits relevant to the novel competitive and plant-herbivore interactions, these experiments failed to reveal evidence that Lotus has responded evolutionarily to the double invasion of Medicago followed by H. brunneipennis. However, when herbivory from H. brunneipennis was experimentally reduced, Lotus plants from source populations invaded by Medicago outperformed plants from uninvaded source populations when transplanted into heavily invaded destination environments. Therefore, Lotus showed evidence of adaptation to Medicago invasion but not to the newer invasion of an exotic shared herbivore. The presence of this exotic insect herbivore alters the outcome of evolutionary responses in this system and counteracts adaptation by the native Lotus to invasion by the exotic plant Medicago. This result has broad implications for the conservation of native communities. While native species may be able to adapt to the presence of one or a few exotics, a multitude of invasions may limit the ability of natives to respond evolutionarily to the novel and frequently changing selection pressures that arise with subsequent invasions.     

Community-level consequences of invasion: impacts of exotic clonal plants on riparian vegetation

Biological invasions by exotic species are occurring at exceptional rates and spatial scales worldwide and are increasingly recognized as key forms of global environmental change. Despite this growing prominence, surprisingly few ecological studies have quantified the impacts of exotic taxa on the plant communities they invade, and this is especially evident in riparian ecosystems. Along the Russian River in northern California, we used both comparative and experimental studies to investigate the influence of two exotic clonal plant species—giant reed (Arundo donax) and blue periwinkle (Vinca major)—on the composition of riparian plant communities. Our results indicate that Arundo invasion was associated with significantly lower richness of native perennial plant species on stream banks and floodplains, whereas there was no relationship on gravel bars. Additional research showed that plots invaded by Arundo and Vinca, both individually and collectively, exhibited significantly lower native and exotic species richness and abundance of both established plants and seedlings than uninvaded plots. Finally, after 2 years, experimental reductions of Arundo biomass via cutting and herbicide resulted in significantly increased native plant species richness and abundances of both established plants and seedlings, while having no effects on other exotics. In summary, our results indicate that Arundo and Vinca have strongly negative effects on diverse components of a riparian plant community, which must be addressed via effective control and restoration efforts.     

淡水鱼类入侵种的分布、入侵途径、机制与后果

生物入侵已经成为全球面临的三大环境问题之一。鱼类入侵现象也随全球经济一体化的进程日益严重。本文综述了全球淡水鱼类入侵的现状和研究进展, 包括鱼类入侵的定义及分布、入侵途径和机制、产生的生态和社会经济影响以及预防措施等。据统计, 目前全球外来鱼类达624种, 该数量超过30年前的两倍。外来鱼类主要通过水产养殖(51%)、观赏渔业(21%)、休闲垂钓(12%)、渔业捕捞运输(7%)等多种途径被引进。入侵鱼类对本地种产生了捕食、种内种间竞争、杂交和疾病传播等负面影响, 破坏本地生态系统, 但是其正面的生态及社会经济影响也不可忽略。近20年来全球鱼类入侵日益受到重视, 相关论文发表数量翻了8倍。值得提出的是, 近10年来全球鱼类入侵风险评价系统的研究显著增加, 一些鱼类入侵模型已应用于五大洲的多个国家。我国淡水外来鱼类共计439种。然而, 我国关于鱼类入侵的研究起步较晚, 发表文献数仅占全球的3.7%, 且主要研究方向仍集中在入侵物种的分布及生物学特性等基础研究上, 缺乏对于鱼类入侵机制及风险评价预测的研究。因此, 我们建议: (1)开展全国范围的本底调查并建立数据库, 实现数据共享, 明确鱼类入侵的历史与分布现状; (2)联合多个政府部门和机构, 对鱼类入侵进行长期观测, 从整个水生生态系统的角度出发, 深入了解其入侵机制及其产生的正面和负面生态和社会经济影响; (3)加强增殖放流的科学研究和管理; (4)构建区域性外来鱼类入侵风险评价系统, 有效预测鱼类入侵活动, 评价入侵种的危害, 并为相关政府部门的决策提供科学依据。     

植物外来种入侵及其对生态系统的影响

对植物外来种的入侵及生态系统的影响进行综述与分析，植物入侵多种因子的影响，可分为外因和内因两类，植物外来种对生态系统的影响主要体现在生产力，土壤营养，水分，干扰体制，群落的结构和动态等方面，在管理外来种时，需对外来种的特性和影响因子进行系统的观察研究，采用机械法，化学方法和生物控制法等综合办法控制植物的入侵，引进植物引来种时，要对引进种的行为特性进行了调查研究，注意其安全性。     

Global distribution,entry routes,mechanisms and consequences of invasive freshwater fish

Biological invasion is now considered one of the three major environmental issues worldwide. Freshwater fish invasion becomes more serious with globalization of the world economy. We reviewed the current status of global freshwater fish invasions and discussed the definitions, distributions, introduction pathways, mechanisms, ecological and economic impacts, and risk assessments of freshwater fish invasions. Non-native fish are mainly introduced through food aquaculture (51%), as ornamental fish (21%), or for sport fishing (12%) and fisheries (7%). The number of introduced fish has reached 624 species, doubled the number found thirty years ago. Successful invasions may bring many negative ecological consequences, such as predation, hybridization, structure and function alteration of local freshwater ecosystems, as well as diseases transmission. However, it also brings positive biological and economic values. The number of fish invasion studies has increased eight times over the last 20 years, with studies mainly focusing on biology and the biological impact of invasive fish species. Risk assessments of freshwater fish invasions were studied over the last 10 years, and fish invasiveness screening models have been applied in countries of five continents. The number of non-native freshwater fish in China totaled 439. However, research papers on freshwater fish invasions in China was only 3.7% of the global total, and these researches were mainly on the distribution and biology of invasive fish species, and very few studies included risk assessments. Therefore, we suggest investigating the history, distribution, and mechanisms of invasive species at the national level, evaluating both the positive and negative effects of freshwater fish invasions, and also reinforcing studies of risk assessments in China.     

入侵植物替代控制中土著种选择机制的研究

生物入侵对入侵地生态系统的稳定性及社会经济造成严重危害,成为全球三大环境问题之一。为有效治理入侵植物,结合常采用的物理、化学和生物防治等方法,从防治机制方面分析土著种替代控制入侵植物的有效性。通常土著种替代控制入侵植物是由于土著植物向环境中分泌化感物质,使得土壤中的微生物、动物以及化学成分相互作用,从而改变了入侵植物的生存环境。同时,土著植物利用自身的优势条件与入侵植物进行养分和光能等资源竞争,使入侵植物处于不利地位。通过对替代控制机理的概述,提出了替代植物的选择方法,讨论了需要进一步加强的领域,以期拓展替代控制这一领域的广度和深度,为入侵植物的生态防治提供理论依据。     

Effects of eutrophication and exotic crayfish on health status of two Spanish lakes: a joint application of ecological indicators

Lake Sentiz and Lake Chozas are two small water bodies in the Province of León (NW Spain). The former is mesotrophic and the latter went from oligotrophic to turbid in 1997, due to introduction of an invasive allochthonous crayfish Procambarus clarkii (Rodríguez et al., 2003, Rodríguez et al., 2005, Marchi et al., 2011a, Marchi et al., 2011b). We set out to study health status of the two ecosystems by the joint use of different but correlated ecological indicators, supplementing the values obtained by monitoring campaigns. We examine three scenarios: (1) Lake Sentiz, (2) Lake Chozas before and (3) Lake Chozas after the biological invasion. We evaluate eco-exergy, emergy and eco-exergy–empower ratio, three holistic ecological indicators based on the thermodynamics of far-from-equilibrium systems. When structural changes take place in ecosystems it is recommended to apply holistic thermodynamic indicators as presented in Jørgensen et al., 2010a, Jørgensen et al., 2010b. We propose their joint application for a complete overview of the monetary value of natural capital, because they provide information added to statistical analysis and direct measurement. The aim is to determine which of these indicators best represents the effects of eutrophication and perturbations caused by alien species in the two freshwater systems. The eco-exergy–empower ratio gives the best results, since it clearly indicates lake efficiency in transforming direct and indirect solar energy inputs into organization. The eco-exergy (work capacity) results are used to estimate ecosystem services and quantify the economic value of lake natural capital. Calculation of ecosystem services on an eco-exergy basis provides good indications of monetary gains or losses possible in perturbed systems, including eutrophic or invaded ecosystems. This is not surprising, because work capacities include all possible services offered by ecosystems, not only the services actually used by humans. Eco-exergy and the eco-exergy–empower ratio can be guidelines for the calculation of ecosystem services, although they give only a partial indication of the environmental costs and benefits of a given level of information. The present results suggest political and economic considerations and solutions, and are a useful example for organisations involved in environmental management of pollution and biological invasions by exotic species.