福建省农田生态系统外来入侵植物种类及其分布

为掌握福建省农田生态系统的外来入侵植物种类和分布情况,采用实地调查的方式,对福建省9市农田生态系统中的入侵植物进行调查,并分析了其种类组成、原产地、生活型、分布格局和分布类型及其入侵性等。结果表明,福建省农田生态系统有外来入侵植物30科65属共79种;其中以菊科（Asteraceae）物种数最多,为22种,占总种数的27.85%,其次是苋科（Amaranthaceae）有7种,豆科（Leguminosae）、禾本科（Gramineae）、旋花科（Convolvulaceae）和大戟科（Euphorbiaceae）各有5种。生活型以草本植物为主,占总种数的86.08%;原产于美洲的种类最多,占总种数的70.24%;入侵等级为恶性入侵（1级）的物种有10科22种,严重入侵（2级）有13科22种,局部入侵（3级）、一般入侵（4级）和有待观察类（5级）分别有9、18和8种;恶性入侵和严重入侵的植物种类占入侵植物总数的55.70%。从分布格局和分布类型来看,以福州市的农田生态系统入侵植物种类最多,为52种;不同农田类型中,以旱地中的入侵植物种数最多,有74种;按分布区域划分的全域分布种共13种,按农田类型划分的全域分布种有11种。因此,福建省农田生态系统入侵植物种类繁多,分布广泛,原产地多元化,且恶性和严重入侵植物占比较高,入侵形势严峻,应加强入侵植物的动态监控与防范,以保护生物多样性和生态安全。     

Optimal conservation strategy in fluctuating environments with species interactions: resource-enhancement of the native species versus extermination of the alien species

Alien species are often a major threat to native species. We consider optimal conservation strategies for a population whose viability is affected both by an alien species (such as a competitor, a predator, or a pathogen) and by random fluctuations of the environment (e.g. precipitation, temperature). We assume that the survivorship of the native population can be improved by providing resources such as food and shelter, and also by an extermination effort that decreases the abundance of the alien species. These efforts decrease the extinction probability of the native population, but they are accompanied by economic costs. We search for the optimal strategy that minimizes the weighted sum of the extinction probability and the economic costs over a single year. We derive conditions under which investment should be made in both resource-enhancement and extermination, and examine how the optimal effort levels change with parameters. When the optimal strategy includes both types of efforts, the optimal extermination effort level turns out to be independent of the density and economic value of the native species, or the variance of the environmental fluctuation. Furthermore, the optimal resource-enhancement effort is then independent of the density of the alien species. However, the parameter dependencies greatly change if one of the efforts becomes zero. We also examine the situation in which the impact of the alien species is uncertain. The optimal extermination effort increases with the uncertainty of this impact except when the cost of extermination is very high.     

Alien vascular plants in Iceland: Diversity,spatial patterns,temporal trends,and the impact of climate change

The present study provides first comprehensive and up-to-date results on alien plant taxa in Iceland since 1967. We evidenced the presence of 336 alien vascular plant taxa, including 277 casuals and 59 naturalised taxa, two being invasive. The distribution of the alien flora exhibits a clear spatial pattern showing hotspots of occurrence and diversity within areas of major settlement centres. Altitude above sea level and temperature-related variables proved to be the most important factors shaping alien plant distribution in Iceland. Predictive modelling evidenced that arctic areas of Iceland and the Central Highlands are under serious risk of alien plant invasion due to climate change. The results provide crucial information for alien and invasive plant management and contribute data for meta-analyses of invasion processes worldwide.     

Delving into the dark ecology: A continent-wide assessment of patterns of composition in soil fungal communities from Australian tussock grasslands

Soil fungi play essential roles in many terrestrial processes, but our knowledge of the forces governing fungal distribution and community composition along broad-scale environmental gradients is still limited. In this study, we explored biogeographic distribution and composition of soil fungal communities associated with 62 tussock grasslands across different regions of Australia. Climatic parameters had only a limited correlation with fungal community structure, while edaphic variables and spatial distance were significantly associated with changes in fungal community composition. We also observed high variations in composition among fungal assemblages from different ecological regions, suggesting some regional endemism in these communities. The discrete distribution of fungi in soil was further confirmed by indicator analysis, which identified distinct indicator operational taxonomic units associated with grasslands from different climatic regions. Finally, fungi with flexible trophic interactions had a central role in the network architecture of both arid and temperate communities. Taken together, the results from our study confirm the prominent role of soil physico-chemical status and geographic location in determining fungal biogeographic patterns over large scales in Australia.     

上海外来植物及其入侵等级划分

汇总分析了上海外来植物75科232属357种(和种下类群)基础资料,并对其入侵危害进行等级划分;其中入侵植物64种,一般或偶见外来植物293种;报道了9种上海新纪录逸生植物。上海外来植物总体呈现种类繁多、国产种类较多、分布密度大、严重危害种类较多且分布广、入侵途径集中等特征。同时对上海外来入侵植物的管理与防治提出具体措施。     

Land use history, hurricane disturbance, and the fate of introduced species in a subtropical wet forest in Puerto Rico

Tropical forests are suffering from increasing intensities and frequency of disturbances. As a result, non-native species accidentally introduced or intentionally planted for farming, plantations, and ornamental purposes may spread and potentially invade undisturbed native forest. It is not known if these introduced species will become invasive, as a result of recurrent natural disturbances such as hurricanes. Using data from three censuses (spanning 15 years) of a 16-ha subtropical wet forest plot, we investigated the impact of two hurricanes on populations of plant species that were planted in farms and plantations that were then abandoned and from the natural spread of species introduced into Puerto Rico in the past. The populations of four species (Citrus paradis, Mangifera indica, Musa sp., and Simarouba glauca) changed little over time. Six species (Artocarpus altilis, Calophyllum calaba, Genipa americana, Hibiscus pernambucensis, Syzygium jambos, and Swietenia macrophylla) declined between the first two censuses after Hurricane Hugo, then increased again in Census 3 after Hurricane Georges. Spathodea campanulata gradually increased from census to census, while Coffea arabica declined. These introduced species represent only a small part of the forest basal area and few show signs of increasing over time. The number of stems per plant, new recruits, and the growth rates of these introduced species were within the ranges of those for native plant species. The mortality rates over both census intervals were significantly lower for introduced species (<5% year⁻¹) than for native ones (15% year⁻¹). Many new recruits established after Hurricane Hugo (prior to this study) had opened the forest canopy and these high mortality rates reflect their death as the canopy recovered. Only Swietenia macrophylla and Syzygium jambos showed an increase in stem numbers in the closed canopy area of forest that had suffered limited human disturbance in the past. A future increase in frequency of disturbance may enable greater stem numbers of introduced species to establish, while lower-mortality rates compared to native species, may allow them to persist during inter-hurricane intervals. An increase in the population of introduced species, especially for those that grow into large trees, may have an impact on this tropical forest in the future.     

Invasive alien plant control: The priority to save one of the most rapidly declining island-endemic plant species worldwide

Up to 6,800 plant species endemic to oceanic islands are highly threatened with extinction. Although habitat destruction and fragmentation have greatly contributed to this, it is generally recognised that invasive alien species currently pose the single most important threat to island plants. Most studies exploring the role of novel interspecific interactions in driving declines of island plants, focus on threats mediated by animals, be it direct (e.g. browsing, seed predation, mutualism disruption) or indirect (e.g. extinction of seed dispersal or pollination mutualists). Relatively few studies have investigated the specific role of plant-plant interactions, particularly in-situ. We studied a threatened island endemic plant in rapid decline to evaluate the short (1–2 years) and medium-term (about 1–2 decades) influence of invasive alien plants (IAPs) on individuals and a variety of proxies of plant fitness. We compared mortality of traceable individuals that were recorded 12–20 years previously between habitats that are invaded with IAPs and habitats where IAPs are absent, or have been removed decades ago. We also carried out an in-situ manipulative experiment using 14 randomly chosen plants from around which IAPs were removed, paired with controls, at two sites. Canopy cover change before and after IAPs’ removal was quantified along with above ground biomass of IAPs removed for use as potential explanatory variables of change in proxies of plant fitness. Ten branches were randomly selected per plant and branch dynamics, leaves’ sizes and reproductive structure production were monitored quarterly for two years. Over the medium term, plant mortality was recorded only in presence of IAPs (X² = 4.80, df = 1, p < 0.05). Over the short term, at the plant level, IAPs’ removal triggered overall weak to moderate improvements in the number of surviving and new branches as well as change in number of branches at one of the sites. At the leaf and branch levels, we found weak evidence for positive effects of IAPs removal on surviving leaves, flower buds produced and difference in leaf surface area per branch in one site. We therefore provide some experimental evidence of negative effects of alien plants on overall fitness of the threatened species in-situ presumably through competitive interactions. We posit that these effects were found to be weak to moderate due to the short experimental period over which they could develop (1–2 years). Overall, IAPs stand out as the most severe threat from among all documented threats to the species, for being the only one capable of causing mortality of adult plants. Results hence highlight island plants’ vulnerability to IAPs, and how their timely control would improve the survival and fitness of threatened plants, even at the scale of single individuals. Such a strategy could be more often employed. Our study stresses on prioritising IAPs’ control for rescuing long-lived threatened plants that grow in habitats invaded by alien plants (itself a very common situation on oceanic islands) before addressing other subtler, slower-acting threats, like disrupted pollination or seed dispersal mutualisms, florivory or seed predation.     

湛江红树林滩涂可培养真菌种群多样性分析

【目的】明确湛江地区红树林滩涂海洋真菌的种类及其分布,为海洋真菌的开发利用研究奠定基础。【方法】运用稀释平板法从湛江市高桥及特呈岛红树林滩涂不同的潮位带(低、中、高)和不同树种(白骨壤、桐花树、木榄、红海榄)采集淤泥样品550份,采用真菌形态学和ITS序列分析技术进行多样性研究【。结果】分离获得海洋真菌274株,共鉴定出19属39种真菌,以曲霉属Aspergillus、青霉属Penicillium和木霉属Trichoderma真菌分离频率高,为湛江红树林滩涂优势真菌种类,尤其在中潮位带真菌种类最多。此外,分离获得真菌Talaromyces helicus,为中国新记录种。【结论】湛江红树林滩涂海洋真菌的种类十分丰富,具有潜在的开发和利用前景。     

The status and causes of alien species invasion in China

Data of classification, origin, pathway and environmental impacts of invasive alien micro-organisms, invertebrates, amphibians and reptiles, fish, birds, mammals, weeds, trees, and marine organisms in terrestrial, aquatic and marine ecosystems of China, were analyzed, based on literature retrieval, field survey and consultation. Some 283 invasive alien species were recorded in China, including 19 invasive alien micro-organisms, 18 aquatic plants, 170 terrestrial plants, 25 aquatic invertebrates, 33 terrestrial invertebrates, 3 amphibians and reptiles, 10 fish, and 5 mammals. Of the invasive alien species, 55.1% originated from North and South America, 21.7% from Europe, 9.9% from Asia, 8.1% from Africa and 0.6% from Oceania. Many institutions and individuals in China lack adequate knowledge of ecological and environmental consequences caused by invasive alien species, with some ignorance of the dangerous invasion in the introduction of alien species. For instance, 50.0% of invasive alien plants were intentionally introduced as pasture, feedingstuff, ornamental plants, textile plants, medicinal plants, vegetables, or lawn plants, 25% of alien invasive animals were intentionally introduced for cultivation, ornament, or biological control, In addition, more efforts are being made in the introduction of alien species, and little attention is paid on the management of introduced alien species, which may cause their escape into natural environment and potential threats to the environment. There were also gaps in quarantine system in China. All microorganisms were unintentionally introduced, through timber, seedling, flowerpot, or soil; 76.3% of alien invasive animals invaded through commodity or transportation facility because of the failure of quarantine. Therefore, quarantine measures should be strictly implemented; and meanwhile the intentional introduction of alien species should be strictly managed and a system of risk assessment should be implemented.     

The failure of the introduction of wild boar Sus scrofa in the island of Cyprus: a case study

Wild boar (Sus scrofa L.) were introduced in the island of Cyprus in 1990, when five animals were imported from Greece for game farming. In 1994, wild boars were illegally released in Lemesos (Limassol) Forest and in 1996 in the Troodos National Forest Park. Soon the population increased and dispersed throughout the park. In 1997, the government of Cyprus decided to eradicate wild boar because of the danger of transmitting diseases to livestock and to prevent possible environmental destruction. To control the wild boar, hunting was permitted and game wardens were instructed to eliminate the free-ranging animals. In 2004, no animals were observed in localities where they had been seen before. Surveys in September 2004 (Troodos National Park) and January/February 2005 (Troodos Forest, Pafos Forest, and Lemesos Forest) revealed no signs of recent wild boar presence. The reasons for the possible failure of wild boar to establish in Cyprus are discussed.     

Modelling the global distribution of fungal species: new insights into microbial cosmopolitanism

Microbes are usually believed to have cosmopolitan distributions. However, for estimating the global distributions of microorganisms, discriminating among cryptic species and eliminating undersampling biases are important challenges. We used a novel approach to address these problems and infer the global distribution of a given fungal ecological guild. We collected mushroom‐forming fungi from Yakushima, Japan. We sequenced the internal transcribed spacer 2 (ITS2) from these samples and queried their sequences against GenBank. After identifying similar sequences, we tracked down the geographical origins of samples that yielded those sequences. We used Bayesian zero‐inflated models to allow for species whose DNA sequences have not yet been deposited in GenBank. Results indicated that the geographical distribution of ectomycorrhizal (ECM) fungi was strongly constrained by host specificity, resulting in the occurrence of these fungi intensively in the neighbouring regions. On the other hand, saprotrophic (SAP) fungi were less constrained by climatic conditions, resulting in a much broader distribution range. We inferred that differences in constraints during colonization between ECM and SAP fungi were responsible for the different geographical distribution ranges. We hypothesize that the degree of host/habitat specificity and the degree of isolation of potentially suitable habitats determine microbial biogeographic patterns.     

Latitudinal variation of life-history traits of an exotic and a native impatiens species in Europe

Understanding the responses of invasive and native populations to environmental change is crucial for reliable predictions of invasions in the face of global change. While comparisons of responses across invasive species with different life histories have been performed before, comparing functional traits of congeneric native and invasive species may help to reveal driving factors associated with invasion. Here we compared morphological functional trait patterns of an invasive species (Impatiens parviflora) with its congeneric native species (I. noli-tangere) along an approximately 1600 km European latitudinal gradient from France (49°34′N) to Norway (63°40′N). Soil nitrogen was recorded during six weeks of the growing season, and light, soil moisture, and nutrient availability were estimated for each sampled population using community weighted means of indicator values for co-occurring species. Temperature data were gathered from nearby weather stations.Both the native and invasive species are taller at higher latitudes and this response is strongest in the invasive species. Seed mass and number of seeds per capsule increase in I. noli-tangere but decrease in I. parviflora towards higher latitudes. Surprisingly, plant height in the invasive I. parviflora decreases with increasing soil nitrogen availability. The latitudinal pattern in seed mass is positively related to temperature in I. noli-tangere and negatively in I. parviflora. Leaf area of both species decreases with increasing Ellenberg indicator values for nitrogen and light but increases with increasing soil moisture. Soil nitrogen concentrations and Ellenberg indicator values for nitrogen have significant positive (I. noli-tangere) and negative (I. parviflora) effects on the number of seeds per capsule. Our results show that the native I. noli-tangere has efficient reproduction at its range edge while the invasive I. parviflora shows a marked decrease in seed size and seed number per capsule. These patterns are unrelated to the growth and obtained size of the plants: even low soil nitrogen availability in the north seemed not to limit plant growth and size. Our results suggest that the invasive I. parviflora tends to become more invasive at lower latitudes by producing heavier seeds and more seeds per capsule.     

Morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex (Chrysophyceae,Stramenopiles)

The Synura petersenii species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (S. borealis, S. heteropora, S. hibernica and S. laticarina) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the S. petersenii complex. Two of these newly described species (S. hibernica and S. borealis) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in S. hibernica could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, S. borealis possesses an exceptionally high degree of genetic diversity, possibly indicating recent speciation and evolutionary diversification within this taxon. Three of the four newly described species exhibit restricted biogeographic distribution. The evolutionarily related S. borealis and S. laticarina occur only in Northern Europe, and seem to be adapted to colder areas. The most remarkable distribution pattern was observed for S. hibernica, which has a geographic distribution that is restricted to western Ireland.     

Juvenile Chinese mitten crabs (<Emphasis Type="Italic">Eriocheir sinensis</Emphasis>) in the Thames estuary: distribution,movement and possible interactions with the native crab <Emphasis Type="Italic">Carcinus maenas</Emphasis>

The Chinese mitten crab, Eriocheir sinensis is a successful invader. Whilst non-breeding adult E. sinensis have been associated with the destruction of riverbanks, little is known about the ecology of this species in its invaded areas. This is especially true of the juveniles which are a key migratory stage. Intertidal surveys along the Thames estuary indicated an increase in the population since the 1990s. Juvenile E. sinensis were abundant in the sampled upper tidal region of the Thames, refuging under boulders in the intertidal at low tide. Seasonal differences in sampled populations were observed, with a significantly lower abundance of crabs found during winter compared to summer. Mark-recaptures indicated movement in the intertidal occurring during high tide, with an influx of new crabs evident after a single tidal cycle. Endogenous rhythms were also apparent, with peaks in activity occurring corresponding with night-time high tide conditions. E. sinensis juveniles can successfully exclude similar sized native Carcinus maenas from shelters in the laboratory, regardless of which species originally inhabited the shelter. This may have implications for native estuarine Carcinus populations, which can rely on such intertidal shelters for refuges.     

Big troubles are already here: risk assessment protocol shows high risk of many alien plants present in Portugal

Invasion by alien plants results in serious adverse impacts on biodiversity, ecosystem services, economy and social welfare, and is an ever-increasing challenge for nature conservation. Control of established invasive species is frequently very difficult and costly. Therefore, predicting which species have risk of becoming invasive is crucial both to prevent introduction of new invaders and to target high risk species already present in order to avoid their spread, particularly to areas with high conservation value. In Portugal more than 600 alien plant species are present as casuals or naturalized, and decision support tools are needed to discriminate which of these have higher probability of becoming invasive. We aimed to assess the effectiveness of the Australian Weed Risk Assessment, adapted to the Portuguese conditions (P-WRA), by evaluating 172 plant species: 49 considered as invasive; and, 123 as non-invasive species. The results showed that the P-WRA correctly identified all invasive species. As for non-invasive species, 17% were accepted, 78% rejected and 5% required further evaluation. Receiver Operating Characteristic (ROC) curve reflected high accuracy of predictions despite lower than that found in other regions. The best cutoff level for P-WRA score, maximizing the ability for classification of the protocol, was 13 resulting in more non-invasive species accepted (46%). In the end, this assessment informed that in addition to the 49 species already invasive, a high number (66) of alien plant species have invasive risk. Amongst these, a list of 20 species is proposed for targeted priority management aiming to prevent their spread. Comparison of the scores obtained with A-WRA for other regions with Mediterranean climate revealed that 17% of the species compared (78) reached different outcomes, signaling the need to be careful when extrapolating the use of previous scores. The P-WRA can be a promising screening system post-border for predicting invasive species already present in Portugal and contribute to the targeting of species for priority intervention, particularly in natural areas with high conservation value.     

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.     

Harmonia axyridis in Great Britain: analysis of the spread and distribution of a non-native coccinellid

Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is native to Asia, and was widely introduced as a biocontrol agent of aphids and coccids in Europe and North America. In Europe H. axyridis is considered to be an invasive alien species. Although not known to have been deliberately introduced to Great Britain, it was first recorded there in 2004, in south-east England. Harmonia axyridis arrived in Great Britain by various means, primarily from mainland Europe, but also from Canada. Extensive national and local media coverage, and a dedicated website (), facilitated public involvement in recording H. axyridis in Great Britain; in excess of 4,000 verified records of the species were received between 2004 and 2006. Through detailed mapping, the objective of our study was to quantify and analyse the spread of H. axyridis in its early stages of invasion in Great Britain. Our data shows that between 2004 and 2006, the species spread north through Great Britain at the rate of 58 km year^-1 and west at the rate of 144.5 km year^-1. In England H. axyridis spread north to Yorkshire and west to Cornwall by the end of 2006, and also reached Wales. Recorded occurrence (of one or more H. axyridis individuals at larval, pupal and/or adult stage) in 10 km squares in Great Britain was: 2004—51; 2005—149; 2006—447. Records of juvenile H. axyridis extend through most of the recorded British range of the species, and we present evidence of bi-voltinism in the population in 2006.     

Can we predict the effects of alien species? A case-history of the invasion of South Africa by Mytilus galloprovincialis (Lamarck)

The Mediterranean mussel Mytilus galloprovincialis invaded the shores of South Africa in about the mid-1970s. It was first detected at a harbour in Saldanha on the west coast and apparently arrived accidentally. From there, it spread at a rate of about 115 km·year⁻¹ and now occupies the whole of the west coast of South Africa and at least the southern half of Namibia. It was deliberately introduced from the west coast to the south coast for mariculture. In this case study, we record its effects on intertidal rocky shores, cast in terms of predictions based on (a) the history of its invasions elsewhere, (b) its mode of dispersal, (c) its physiological performance relative to indigenous mussels, (d) the role of wave action as a moderator of competition, (e) the influence of relative body sizes, (f) the projected effects of the mussel on infauna, (g) consumption by higher trophic levels, and (h) rates of parasitism.

Several properties of M. galloprovincialis itself, and of the recipient community, conspired to favour the spread and establishment of this alien mussel, including high productivity on the west coast of South Africa, prevalently strong wave action, a sparsity of predators, an absence of parasites, the mussel's fast growth and high reproductive output, and its possession of a planktotrophic larva. It competitively displaces several species because of its physiological performance. Some of the species gain a substitute substratum on the mussels themselves, but only if they are small enough to live and reproduce on the mussels. M. galloprovincialis has had little effect on infauna, but has provided an additional source of food for higher predators, including the rare and endangered African Black Oystercatcher (Haematopus moquini).

Nearly all these effects and conditions were forecasted (or, at the least, explainable with hindsight), but despite these successes in predicting the impacts of M. galloprovincialis, its spread was not only unavoidable but was encouraged by its transfer to the south coast for mariculture. Moreover, there was one completely unpredictable effect of M. galloprovincialis—which led to mass mortalities of a swimming crab. Given the failure of even quite detailed and accurate predictions to allow control of M. galloprovincialis once it arrived, prevention rather than cure must be the prime means of avoiding future unwanted introductions of invasive species.