Threats and benefits of invasive alien plant species on pollinators

Invasive alien plant species are usually disliked due to their high pressure on native communities. However, their ecological effects on pollinators are complex: some species provide abundant floral resources, boosting the number of pollinators, while they often disrupt plant-pollinator interactions by outcompeting native plants. Our direct knowledge is mainly based on single-species studies, while understanding the mechanism of these complex ecological interactions needs multi-species field-based approaches. It is also imperative to clarify the pros and cons of invasive plants and drivers of invasion from the perspective of pollinators. We conducted a standard protocol-driven regional study in Central and Eastern Europe, comparing 6-7 invaded and non-invaded sites of 12 herbaceous invasive plant species. We sampled floral resources, bees, and hoverflies before and during the flowering of the invasive plants. We analysed the effects of plant invasion at the invasive plant species level and in combined analyses, and tested whether the life span (perennial vs. annual) and flowering time (early-, middle-, and late-flowering) of invasive plants affect the abundance, species richness, diversity and species composition of native plants and pollinators. The combined analyses showed lower abundance and species richness of flowering plants and pollinators before, and higher abundance of both during the flowering of invasive plants in invaded sites. However, invasive plants had significant species-specific effects. Perennial invasive plants had a stronger negative impact on floral resources and pollinators already before their flowering compared to annuals. Flowering time of invasive plants affected the pollinator guilds differently. We suggest that in certain critical time periods of the year, invasive plants might provide the dominant foraging resources for pollinators in an invaded ecosystem. But, they also often cause significant losses in native floral resources over the year. Instead of simple eradication, careful preparation and consideration might be needed during removal of invasive plants.     

Temperature-dependent performance of competitive native and alien invasive plant species

To assess the likely impacts of environmental change, the responses of two well-known invasive plant species, native Pueraria lobata and alien Humulus japonicus, to differences in growth temperature were studied in South Korea. Habitat preferences, physiological responses such as photosynthetic rates and chlorophyll contents, growth rates, and nutrient contents were quantified for each species. A competition experiment was conducted to evaluate the temperature preferences of the two species. All results indicated that the alien species H. japonicus can take advantage of elevated temperatures (35 °C) to enhance its competitive advantage against the native species P. lobata. While H. japonicus took advantage of elevated temperatures and preferred high-temperature areas, P. lobata showed reduced performance and dominance in high-temperature areas. Therefore, in future, due to global warming and urbanization, there are possibilities that H. japonicus takes advantage of elevated temperature against P. lobata that could lead to increased H. japonicus coverage over time. Therefore, consistent monitoring of both species especially where P. lobata is dominated are required because both species are found in every continents in the world. Controlling P. lobata requires thorough inspection of H. japonicus presence of the habitat in advance to prevent post P. lobata management invasion of H. japonicus.     

The status quo of invasive alien insect species and plant quarantine in Korea

The recent increase in agricultural commodities from abroad and travelers due to the economic growth and globalization in Korea has resulted in an increase in invasive alien insect species establishing in Korea. When “alien” is defined as species introduced after the beginning of the Greater Korean Empire Era (1897), 171 insect species are considered invasive alien species. On average, 0.85 alien insect species have become established each year for the last 40 years, and 76.6% of the alien insect species are economic agricultural pests. The annual invasion rate and the pest interceptions from imported cut flowers, planting material, and vegetables have been increasing rapidly. Traveler's baggage is an important pathway for fruit flies. Most of the alien pests that were first found in Japan were confirmed in Korea at least 3 years later until the 1990s, but the pattern has been reversed since the 2000s. Thus, continuous information sharing with neighboring countries such as Japan and China is needed to develop a system for early detection and prompt action against invading insect species. Thus, we introduce and summarize the present status of invasive alien insect species in Korea.     

Distribution and management of invasive alien plant species in protected areas in Central Europe

Protected areas play a key role in biodiversity conservation, yet they face numerous pressures including the spread of invasive alien species (IAS). We designed a structured online survey to investigate the distribution and management of 53 invasive alien plant species in large protected areas, i.e. national parks and biosphere reserves, in eight Central European countries. We contacted 93 protected areas management authorities, of which 46 replied. In 44 protected areas (96% of those responding), at least one IAS was present, and in 37 protected areas (80%) IAS were managed. On average, 11.2 ± 6.9 IAS were present per protected area and 4.3 ± 3.4 (41%) of these were managed. A one-way ANOVA showed no significant difference in the number of IAS present or managed between the different protected area designations (national parks, biosphere reserves). Similarly, neither the size nor the founding year of the protected area influenced the number of IAS present or managed. Thirty-one species (58%) were managed in at least one protected area. The most widely managed species were Fallopia japonica (23 protected areas), Heracleum mantegazzianum (20), and Impatiens glandulifera (16). The amount of financial resources devoted to IAS management was rather low, corresponding to 3.1 ± 4.4% of the total budget for natural resources management of the protected areas. We conclude that a lack of dedicated funding for IAS management in most protected areas and a lack of coordinated response between protected areas currently limit the effectiveness of the IAS management. In particular, an increased exchange of expertise between protected areas, and the development of minimum standards for IAS surveillance and management are pivotal. In addition, documenting best practice examples and synthesizing lessons learned in IAS management are urgently needed.     

广州的外来植物

该文分析了127种广州外来植物的种类及其生长型、原产地、现状、生境和季节变化。结果表明:具有较强繁殖能力的草本、灌木和藤本植物以及一些世界广布或热带性科属的植物和原产美洲、非洲的一些植物具有较强的入侵能力;受人为干扰较强的路边、荒地、池塘、果园、菜园和人工林容易为外来植物入侵,而人为干扰较少的自然生境则不易为外来植物入侵。此外,文章对物种的入侵性和生境的入侵性问题进行了讨论,认为这实际上是一个问题的两个方面,物种的入侵性总是与被入侵的生境联系在一起并相互影响的。     

Flowering phenology of invasive alien plant species compared with native species in three Mediterranean-type ecosystems

Background and Aims

Flowering phenology is a potentially important component of success of alien species, since elevated fecundity may enhance invasiveness. The flowering patterns of invasive alien plant species and related natives were studied in three regions with Mediterranean-type climate: California, Spain and South Africa''s Cape region.

Methods

A total of 227 invasive–native pairs were compared for seven character types across the regions, with each pair selected on the basis that they shared the same habitat type within a region, had a common growth form and pollination type, and belonged to the same family or genus.

Key Results

Invasive alien plant species have different patterns of flowering phenology from native species in the three regions. Whether the alien species flower earlier, later or at the same time as natives depends on the climatic regime in the native range of the aliens and the proportion of species in the invasive floras originating from different regions. Species invading at least two of the regions displayed the same flowering pattern, showing that flowering phenology is a conservative trait. Invasive species with native ranges in temperate climates flower earlier than natives, those from Mediterranean-type climates at the same time, and species from tropical climates flower later. In California, where the proportion of invaders from the Mediterranean Basin is high, the flowering pattern did not differ between invasive and native species, whereas in Spain the high proportion of tropical species results in a later flowering than natives, and in the Cape region early flowering than natives was the result of a high proportion of temperate invaders.

Conclusions

Observed patterns are due to the human-induced sympatry of species with different evolutionary histories whose flowering phenology evolved under different climatic regimes. The severity of the main abiotic filters imposed by the invaded regions (e.g. summer drought) has not been strong enough (yet) to shift the flowering pattern of invasive species to correspond with that of native relatives. It does, however, determine the length of the flowering season and the type of habitat invaded by summer-flowering aliens. Results suggest different implications for impacts at evolutionary time scales among the three regions.Key words: Biological invasions, flowering phenology, genetic inertia, Cape Floristic Region, California, Spain, Mediterranean-type ecosystems, water availability, climatic origin     

全球外来入侵生物与植物有害生物数据库的比较评价

[目的]为了明确全球生物安全与植物保护领域内数据库建设进展和我国数据库的建设成效,对全球重要的外来入侵生物与植物有害生物数据库进行分类介绍和比较评价研究.[方法]根据数据库收录物种的地理范围、类群及数据库特色功能,对数据库进行分类.对重要数据库的主要功能进行简要介绍,设立多指标评价体系将我国数据库与国际优质数据库进行比...     

中国外来入侵生物的空间分布格局及其影响因素

不同地理区域影响生物分布格局的因子不同,对外来入侵物种也是如此。在区域尺度上分析外来入侵生物的空间分布格局及其影响因子对预测生物入侵的影响及入侵种的控制管理具有重要意义。本研究应用中国外来入侵物种数据库、自然环境数据库和社会人文环境数据库,分析了我国外来入侵动植物的空间格局;并运用主成分分析（PCA）和典范对应分析（CCA）探讨了自然环境和人类活动等因素对外来入侵动植物分布格局的影响;同时研究了外来入侵物种多样性与本地物种多样性之间的关系。结果表明,我国现有外来入侵动物138种、入侵植物384种,其数量和密度都呈现出由东南沿海向西北内陆减少的趋势,且入侵动物和入侵植物空间格局基本一致;降水（MAP）是决定我国外来入侵动植物分布格局的主要自然环境因子,国民生产总值（GDP）是主要社会经济影响因子。在全国尺度上,外来入侵物种多样性与本地物种多样性之间呈显著的正相关关系,但地域间存在较大差异。不同区域外来入侵物种与本土物种多样性的相关关系表现出不同,与研究尺度有密切关系。     

外来入侵植物对环境梯度和天敌逃逸的适应进化

进化假说认为, 在入侵地外来种能发生遗传变化, 以适应新的环境, 最终成功定殖和扩散。种内或种间杂交、遗传漂变、新环境带来的新的选择压力等是促使外来种发生进化的重要原因。在入侵地, 响应来自非生物和生物因素的选择压力是外来种发生适应进化的主要原因。本文主要介绍外来植物如何通过进化适应入侵地的纬度、海拔等非生物环境和天敌逃逸等生物环境。关于外来入侵植物对纬度和海拔等环境梯度的适应进化, 本文在强调表型进化研究应与分子标记研究相结合的基础上, 介绍了一些同质种植园实验和交互移植实验。关于外来入侵植物对天敌逃逸的适应进化, 本文主要介绍增强竞争能力的进化假说和修正的增强竞争能力的进化假说, 及其在理论上和验证方法上存在的问题。最后, 本文介绍了氮分配的进化假说, 该假说认为天敌逃逸可使外来入侵植物降低叶氮向防御的分配, 同时增加氮向光合的分配。     

Ecological genetics of invasive alien species

There is growing realisation that integrating genetics and ecology is critical in the context of biological invasions, since the two are explicitly linked. So far, the focus of ecological genetics of invasive alien species (IAS) has been on determining the sources and routes of invasions, and the genetic make-up of founding populations, which is critical for defining and testing ecological and evolutionary hypotheses. However an ecological genetics approach can be extended to investigate questions about invasion success and impacts on native, recipient species. Here, we discuss recent progress in the field, provide overviews of recent methodological advances, and highlight areas that we believe are of particular interest for future research. First, we discuss the main insights from studies that have inferred source populations and invasion routes using molecular genetic data, with particular focus on the role of genetic diversity, adaptation and admixture in invasion success. Second, we consider how genetic tools can lead to a better understanding of patterns of dispersal, which is critical to predicting the spread of invasive species, and how studying invasions can shed light on the evolution of dispersal. Finally, we explore the potential for combining molecular genetic data and ecological network modelling to investigate community interactions such as those between predator and prey, and host and parasite. We conclude that invasions are excellent model systems for understanding the role of natural selection in shaping phenotypes and that an ecological genetics approach offers great potential for addressing fundamental questions in invasion biology.     

中国外来入侵种的类群、原产地及变化趋势

随着我国对外开放范围的不断扩大,无意引进的入侵种对我国农林生产和生态安全的威胁进一步加大,但至今鲜有关于我国外来入侵种的类群组成、原产地结构及其变化趋势的系统报道。因此,本文对我国234种无意引进的外来入侵种进行研究,以期为口岸检疫与监测提供参考。结果发现,这些物种属于7界16门27纲65目122科。昆虫纲和木兰纲的入侵种分别占总数的28.2%和33.3%。原产于美洲和欧洲的入侵种分别占总数的51.7%和24.4%。1969～2008年,昆虫纲的入侵种每10年的增加数量及其在每10年新增的所有入侵种中所占的比例均呈明显的上升趋势,分别从1969～1978年的2种和12.5%增加到1999～2008年的17种和77.3%。1899～2008年,原产于美洲的入侵种在每10年新增的所有入侵种中所占的比例基本稳定在55%～65%。1959～2008年,每10年新增的原产于美洲的入侵种中,昆虫所占的比例明显增加,从1959～1969年的0增加到1999～2008年的81.8%。这表明昆虫已成为我国外来入侵种中最主要的类群之一,美洲仍是其最主要的原产地之一。     

Interference competition between alien invasive gammaridean species

The relative abundances of gammaridean species in the river Rhine have profoundly changed since the invasion of Dikerogammarus villosus in 1994/1995. This study tested whether these changes in gammaridean dominance could have been determined by interspecific competition and unequal mortality, for example by intraguild predation (IGP). Single and two species tests have been carried out in aquariums provided with all substrata present in the main channel of the Rhine. Changes in substratum choice, increased swimming activity and increased mortality of a species were used as indicators of interspecific competition during interaction between gammaridean species. Interspecific competition and mortality between the most abundant invasive gammaridean species in the Rhine, viz. Gammarus tigrinus, Echinogammarus ischnus and Dikerogammarus villosus were tested. In single-species experiments, G. tigrinus and D. villosus showed similar preferences for a stony substratum, whereas E. ischnus mostly occupied the water column. The two-species aquarium experiments indicated direct interference competition for substratum and unequal mortality between G. tigrinus and D. villosus, with D. villosus being the stronger competitor. Competitive stress was influenced by population density, was size-dependent and varied between the different types of substratum due to substratum choice. G. tigrinus did not show any behaviour indicative of interference competition in the presence of E. ischnus, and neither did E. ischnus or D. villosus in the presence of any of the other gammarideans. Swimming in the water layer may already enable E. ischnus to minimise its encounters with the stone-dwelling D. villosus and G. tigrinus. To maximise the encounters between E. ischnus and D. villosus, a fish (Lepomis gibbosus) was added to occupy the water layer during the aquarium experiments. E. ischnus showed a higher mortality in the presence of both D. villosus and fish, probably due to increased stress, as shelter opportunities to escape the predators had been minimised. The study shows that interference competition between gammaridean species can explain the replacement of the North American invader G. tigrinus by D. villosus in the river Rhine. E. ischnus and D. villosus both Ponto-Caspian invaders did not show interference competition in our experiments and co-exist in the Rhine.     

我国外来入侵生物防控现状、问题和对策

外来物种入侵已经威胁全球多个国家和地区,严重影响农林牧渔业生产,威胁生态系统稳定,是当前全球生物多样性丧失的主要原因之一,开展入侵物种防控已成为生物多样性保护与农业绿色发展的重点工作。我国已经成为全球遭受生物入侵威胁与损失最为严重的国家之一,截至2018年底,入侵我国的外来物种有近800种,已确认入侵农林生态系统的有638种,全国31个省（区、市）均有外来生物入侵发生并带来危害,半数以上县域都有入侵物种分布,几乎涉及所有类型的生态系统。本文对全球主要发达国家外来入侵物种发生情况及防控进行梳理发现,从国家层面立法开展外来入侵生物防控成为主流,制定长期防控战略并增加投入是入侵物种防控成功的关键。近些年,我国在外来入侵物种防控方面初步建立了工作机制,发布了重点管理外来入侵物种名录,完成了重点入侵物种的调查监测,开展了局部地区的防控措施,积极推动立法工作。根据国外生物入侵防治经验与我国实际情况,本研究提出我国外来入侵物种防控对策建议,包括加强法制建设、开展本底调查和启动重大防控工程等,为我国外来侵入生物的防控提供借鉴。     

中国大陆一新外来入侵种--刺桐姬小蜂

报道了最近发生在广东省深圳市、福建省厦门市等地刺桐等桐属植物上的一种新的外来人侵害虫——刺桐姬小蜂Quadrastichus erythrinae Kim。对其分类地位、形态特征、生物学特性、分布、寄主、为害症状等做了简要介绍,提出防治措施,并对其风险分析进行评估。     

Modelling the damage costs of invasive alien species

Biological Invasions - The rate of biological invasions is growing unprecedentedly, threatening ecological and socioeconomic systems worldwide. Quantitative understandings of invasion temporal...