Alien invasive species in Siberia:current status and problem

Although alien and invasive plant species have been researched extensively in the European part of Russia,the situation in Siberia is another matter.Hitherto,alien and invasive species in Siberia have not received much attention because this problem was not especially acute in Siberia.The lack of attention on alien and invasive species in Siberia is attributed to three major reasons:1) Low vegetative productivity and sparse human populations in the Siberian territory have limited botanical research interest in the area.2) Severe Siberian climate likely prevents many alien and invasive species from increasing their distribution into Siberia.3) Most Siberian plant communities have not been human-transformed and thus may be resistant to newcomers.Nevertheless,recent increased economic activities have resulted in increasing plant migration to Siberia,and this process should be monitored.Furthermore,global environmental changes may also have made Siberia more favorable for more alien and invasive species.Currently,research on alien and invasive species has begun in the Altai-Sayan region(Western Siberia) and the Magadan region(Northeastern Asia).     

Vegetation composition and distribution on the northern slope of Karlik Mountain to Naomaohu basin, East Tianshan Mountains

This paper reports the characteristics of plant flora in the region of the northern slope of Karlik Mountain to Naomaohu basin,based on field investigation of the vegetation and referring to relevant literature. The results show that the flora of the study area mainly consists of communities of single species or a limited number of species,genera and families. The flora composition is marked by the phenomenon of dominant families and genera;the temperate element occupies a dominant position,while in terms of the genera the Tethys element is an important component. Areal-types of the species are dominated by the floral element of Asian Central-part with xerophytic characteristic,and the life-forms of plants are mainly perennial and herbaceous. These characteristics reflect that the compositions of the species in this region possess both ancient and young elements. Analysis of the relationship between the species composition,plant community diversity and altitude gradient,we found that the structure of the vegetation has an obvious vertical distribution. The lower and higher altitude areas,where the climate conditions are relative inclement,are mainly occupied by the plant communities with simple structure and single dominant population,while the species richness in the mid-altitude area increases with favorable temperature and precipitation. Consequently,the species diversity and evenness indices show single-peak distribution with increasing elevation(about < 2500 m) ,while the dominance indices decrease in elevation from 500 m to 2500 m and increase in elevation of > 2500m.     

Fluctuating resources, disturbance and plant strategies:diverse mechanisms underlying plant invasions

This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al.(2000).I measured relative functional responses of both invasive and native plants to changed resource availability due to nutrient enrichment and rainfall,and to increased disturbance.Data are presented from studies in two contrasting ecosystems.First is a series of glasshouse and field experiments on the invader Hieracium lepidulum and associated invasive and native species in subalpine temperate New Zealand.Second is a field study of invasive and native plant responses to altered disturbance regimes and rainfall from tropical savannas of north eastern Australia.Invaders responded differently from native species to changes in resource availability in both subalpine and tropical studies.However,invaders differed among themselves showing that different species exploit different functional niches to invade their respective habitats.These findings contribute to the contention that the fluctuating resource hypothesis does not provide a universal explanation for plant invasions.The diverse functional responses to increased resource availability among invaders in this and previous studies suggest that the cause of invasion depends on unique combinations of habitat and functional attributes of invaders and native assemblages.Such findings imply that universal predictions of what will happen under climate change scenarios across the globe will be difficult to make.     

Soil characteristics and plant distribution in saline wetlands of Oued Righ,northeastern Algeria

Saline wetlands are rare ecosystems in Saharan areas,which are important for conservation of many endemic and rare plant species.In this study,we investigated five saline wetland sites of the Oued Righ region,located in the northeastern Algeria,to determine the environmental factors controlling the composition and distribution of plant communities.We established a total of 20 transects to measure the vegetation parameters(density and cover) and soil characteristics(electrical conductivity,moisture,pH,CaSO_4,CaCO_3,organic matter,Na~+,K~+,Mg~(2+),Ca~(2+),SO_4~(2–),Cl~–,NO_3~– and HCO_3~–).A total of 17 plant species belonging to seven families were identified.The natural vegetation was composed of halophytic and hydro-halophytic plant communities,presented specially by the species of Amaranthaceae family.Soils in the studied wetlands were moist,gypsiferous,alkaline,salty to very salty with dominance of chloride and calcium.Results of the Canonical Correspondence Analysis(CCA) showed that community structure and species distribution patterns of vegetation were mainly dependent on soil characteristics,mainly being soil salinity(CaSO_4,K~+,Ca~(2+) and Cl~–) and moisture.The distribution of plant species was found to follow a specific zonal pattern.Halocnemum strobilaceum was observed to grow in highly salt-affected soils,thus being the more salt-tolerant species.Phragmites communis plants were widely distributed in the study area with a high density at the edges of accumulated water body.Juncus maritimus,Tamarix gallica and Salicornia fructicosa grew in soils that are partially or completely flooded in winter.Suaeda fructicosa,Traganum nudatum,Arthrocnemum glaucum,Aeluropus littoralis,Cressa cretica and Cynodon dactylon were distributed in salty and moist soils away from the open water body.Plants of Zygophyllum album,Limonastrirum guyonianum,Cornulaca monacantha,Cistanche tinctoria,Mollugo nudicaulis and Sonchus maritimus were found in soils with less salty and moisture.They constituted the outermost belt of vegetation in the studied wetlands.This study will provide a reference on introducing the salt-tolerant plant species as a fodder resource in saline habitats and regenerating the degraded saline wetlands.     

Effects of parasitic plant Cistanche deserticola on chlorophyll a fluorescence and nutrient accumulation of host plant Haloxylon ammodendron in the Taklimakan Desert

The parasitic plant Cistanche deserticola attaches to Haloxylon ammodendron, a perennial shrub with high tolerance to salinity and drought. However, little was known about the parasite-host relation between the two species. Effects of the parasite on chlorophyll a fluorescence and nutrient accumulation in the host plant (H. ammodendron) were investigated in the Taklimakan Desert. Some photosynthetic parameters of both host and non-host H. ammodendron plants were measured by in vivo chlorophyll a fluorescence technology in the field. The assimilating branches of host and non-host plants were collected and nutrient and inorganic ion contents were analyzed. The results from field experiments showed that the infection of C. deserticola reduced the non-photochemical quenching of the variable chlorophyll fluorescence (NPQ) and the potential maximum quantum yield for primary photochemistry (F v /F m ) of the host. Compared with non-host plants, the host H. ammodendron had low nutrient, low inorganic ion contents (Na + and K + ) and low K + /Na + ratios in the assimilating branches. It suggested that C. deserticola infection reduced the nutrient acquisition and caused damage to the photoprotection through thermal dissipation of the energy of the photosystem II in the host, resulting in a decrease in the tolerance to salinity and high radiation. It was concluded that the attachment of the parasite plant (C. deserticola) had negative effects on the growth of its host.     

Growth and sustainability of Suaeda salsa in the Lop Nur,China

Extremely saline soils are very harsh environments for the growth and survival of most plant species, however, halophytes can grow well. The underlying mechanism of halophyte to resist high saline is not well understood by us. This study was conducted at the potash mine near the Lop Nur, China, where the effects of the halophyte Suaeda salsa L. on the saline-alkaline soils and its growth and sustainability were investigated. Four plots(in which the salt encrustation layers were removed), with different soil treatments were evaluated:(1) undisturbed soil, with no additional treatment(T1);(2) the slag soil zone, in which a 40-cm layer of slag was placed on the undisturbed soil surface(T2);(3) slag+sandy soil, in which a 20-cm layer of slag was placed in the lower layer and 20 cm of sandy soil, taken from an area about 70 km away from Lop Nur potash mine, where Tamarix species were growing, was placed in the upper layer(T3); and(4) a 40-cm sandy soil layer taken from the area where Tamarix species were growing was placed on undisturbed soil(T4). Soil nutrient contents increased in the four treatments, but salt content only decreased in the T1 treatment. Salt content in the T4 treatment increased over the two-year period, which may be partly attributed to salt deposition from wind-blown dust within the mine and salt accumulation within the surface soil(0–20 cm) in response to high evaporative demands. The S. salsa plants exhibited greater improvements in growth under the T4 treatment than under the T1, T2, and T3 treatments, which demonstrated that low levels of salinity are beneficial for the growth of this species. The T1 treatment was sustainable because of its low cost and superior soil improvement characteristics. Therefore, S. salsa plants not only reduced soil salinity and increased soil nutrient levels, but also ameliorated the plant growth environment, which would be beneficial for both the ecological restoration of the Lop Nur area and similar areas throughout the world.     

Origin and circulation of saline springs in the Kuqa Basin of the Tarim Basin,Northwest China

It is widely accepted that hydrogeochemistry of saline springs is extremely important to understand the water circulation and evolution of saline basins and to evaluate the potential of potassium-rich evaporites.The Kuqa Basin,located in the northern part of the Tarim Basin in Northwest China,is a saline basin regarded as the most potential potash-seeking area.However,the origin and water circulation processes of saline springs have yet to be fully characterized in this saline basin.In this study,a total of 30 saline spring samples and 11 river water samples were collected from the Qiulitage Structural Belt(QSB)of the Kuqa Basin.They were analyzed for major(K^+,Ca2^+,Na^+,Mg2^+,SO42-,Cl-and HCO3-)and trace(Sr2^+and Br-)ion concentrations,stable H-O-Sr isotopes and tritium concentrations in combination with previously published hydrogeochemical and isotopic(H-O)data in the same area.It is found that the water chemical type of saline springs in the study area belonged to the Na-Cl type,and that of river water belonged to the Ca-Mg-HCO3-SO4 type.The total dissolved solid(TDS)of saline springs in the QSB ranged from 117.77 to 314.92 g/L,reaching the brine level.On the basis of the general chemical compositions and the characteristics of the stable H-O-Sr isotopes of saline springs,we infer that those saline springs mainly originated from precipitation following river water recharging.In addition,we found that saline springs were not formed by evapo-concentration because it is unlikely that the high chloride concentration of saline springs resulted in evapo-concentration and high salinity.Therefore,we conclude that saline spring water may have experienced intense evapo-concentration before dissolving the salty minerals or after returning to the surface.The results show that the origin of salinity was mainly dominated by dissolving salty minerals due to the river water and/or precipitation that passed through the halite-rich stratum.Moreover,there are two possible origins of saline springs in the QSB:one is the infiltration of the meteoric water(river water),which then circulates deep into the earth,wherein it dissolves salty minerals,travels along the fault and returns to the surface;another is the mixture of formation water,or the mixture of seawater or marine evaporate sources and its subsequent discharge to the surface under fault conditions.Our findings provide new insight into the possible saltwater circulation and evolution of saline basins in the Tarim Basin.     

Profiling soil free-living nematodes in the Namib Desert,Namibia

Functional structure and diversity of soil free-living nematodes in a desert environment depend on plant gender and sampling site.The objective of this study was to compare the composition,abundance and tropic group of soil free-living nematodes in the upper 0–10 cm soil layer under the male and female Acanthosicyos horridus Welw.ex Hook.f.plants and in the inter-shrub open areas(control)in the Namib Desert,Namibia in April 2015.Soil moisture,organic matter(OM)and pH was also analyzed.Free-living nematodes were extracted from 100 g soil using the Baermann funnel procedure,and total number of nematodes was counted under a microscope.Community composition and diversity of soil free-living nematodes were analyzed using 18S rDNA sequences.Results indicated that a total of 67 groups,including 64 species,2 genera and 1 family were identified.Feeding behavior of 58 species were identified as follows:15 bacteria-feeding species,12 fungi-feeding species,10 plant-parasite species,5 omnivorous-predator species,8 animal-parasite species,5 invertebrate-parasite species and 3 non-free-living nematodes,known as marine species.Moreover,soil free-living nematodes were found to be affected by sampling locations and plant gender,and community composition and density of these nematodes were strongly influenced by soil OM content.Result confirmed that spatial location and plant cover were main factors influencing the diversity of soil free-living nematodes.Moreover,molecular tools were found to be very useful in defining the richness of soil non-free-living nematodes.In conclusion,the results elucidated the importance of biotic variables in determining the composition and abundance of soil free-living nematodes in the Namib Desert,Namibia.     

What makes Haloxylon persicum grow on sand dunes while H. ammodendron grow on interdune lowlands： a proof from reciprocal transplant experiments

Determining the mechanisms underlying the spatial distribution of plant species is one of the central themes in biogeography and ecology. However, we are still far from gaining a full understanding of the autecological processes needed to unravel species distribution patterns. In the current study, by comparing seedling recruitment, seedling morphological performance and biomass allocation of two Haloxylon species, we try to identify the causes of the dune/interdune distribution pattern of these two species. Our results show the soil on the dune had less nutrients but was less saline than that of the interdune; with prolonged summer drought, soil water availability was lower on the dune than on the interdune. Both species had higher densities of seedlings at every stage of recruitment in their native habitat than the adjacent habitat. The contrasting different adaptation to nutrients, salinity and soil water conditions in the seedling recruitment stage strongly determined the distribution patterns of the two species on the dune/interdune. Haloxylon persicum on the dunes had lower total dry biomass, shoot and root dry biomass, but allocated a higher percentage of its biomass to roots and possessed a higher specific root length and specific root area by phenotypic traits specialization than that of Haloxylon ammodendron on the interdune. All of these allowed H. persicum to be more adapted to water stress and nutrient shortage. The differences in morphology and allocation facilitated the ability of these two species to persist in their own environments.     

Changes in sediment discharge in a sediment-rich region of the Yellow River from 1955 to 2010： implications for further soil erosion control

The well-documented decrease in the discharge of sediment into the Yellow River has attracted considerable attention in recent years. The present study analyzed the spatial and temporal variation of sediment yield based on data from 46 hydrological stations in the sediment-rich region of the Yellow River from 1955 to 2010. The results showed that since 1970 sediment yield in the region has clearly decreased at different rates in the 45 sub-areas controlled by hydrological stations. The decrease in sediment yield was closely related to the intensity and extent of soil erosion control measures and rainstorms that occurred in different periods and sub-areas. The average sediment delivery modulus(SDM) in the study area decreased from 7,767.4 t/(km2?a) in 1951–1969 to 980.5 t/(km2?a) in 2000–2010. Our study suggested that 65.5% of the study area with the SDM below 1,000 t/(km2?a) is still necessary to control soil deterioration caused by erosion, and soil erosion control measures should be further strengthened in the areas with the SDM above 1,000 t/(km2?a).     

北京市湿地入侵植物群落与本地植物群落的生物多样性比较

为明确外来入侵植物对本地湿地植物多样性的影响，在北京市湿地选择23个样地共245个样方进行物种多样性调查，并从不同植物性状数据库获取样方中所有植物的株高、叶长、叶宽、叶面积和比叶面积等10个功能性状数据，对比分析入侵群落与本地群落的物种多样性、系统发育多样性和功能多样性特征。结果显示，在北京市湿地共记录到26种外来入侵草本植物，隶属10科19属，其中，菊科外来入侵植物种类最多，有10种。除比叶面积、叶片碳含量和株高的系统发育信号显著外，其余7种植物功能性状的系统发育信号均不显著，表明大多数功能性状未表现出系统发育保守性。入侵群落所有物种的物种多样性指标Shannon-Wiener多样性指数、物种丰富度指数和Simpson优势度指数以及系统发育多样性指标谱系多样性和平均最近谱系发育距离均显著高于本地群落和入侵群落本地物种，而入侵群落本地物种的功能分散指数和Rao''Q二次熵指数均显著高于本地群落，表明外来物种入侵改变了湿地植物的生物多样性，且外来物种入侵后群落谱系多样性趋于发散，说明与本地植物亲缘关系越远的入侵物种越容易在湿地群落中建立种群，符合达尔文归化假说。     

长沙地区典型生境中外来入侵植物组成及入侵危害研究

为了全面摸清长沙地区典型生境中外来入侵植物的种类构成、区系组成,为保护长沙地区本地生态系统,防止外来植物的入侵危害提供决策依据,以长沙市9种土地利用类型、22种生境类型为调查对象,采取标准样地法、样方法、样线法进行外来入侵植物实地调查,通过文献资料对调查物种进行了补充。调查结果表明,长沙地区有外来入侵植物116种,隶属38科83属,其中菊科(29种)、豆科(12种)及苋科(11种)为优势科,占物种总数的44.83%;种类最多的属为苋属(5种)和大戟属(5种)。原产地分析结果表明,81种外来入侵植物来自美洲地区,占物种总数的69.83%。从入侵等级来看,处于恶性入侵种(1级)、严重入侵种(2级)、局部入侵种(3级)的物种数分别为21、24、14种。植物区系分析结果显示,长沙地区外来入侵植物科的主要分布类型为世界广布、泛热带分布;属的主要分布类型依次为泛热带分布、世界分布、东亚(热带、亚热带)及热带南美间断分布、北温带分布。     

The EPPO prioritization process for invasive alien plants

Although invasive alien plants are gaining increased attention within EPPO countries, there is no existing widely agreed method to identify those alien plants that are considered invasive and represent the highest priority for pest risk analysis. In the framework of the ad hoc Panel on Invasive Alien Species, EPPO proposes a prioritization process for invasive alien plants designed (i) to produce a list of invasive alien plants that are established or could potentially establish in the EPPO region and (ii) to determine which of these have the highest priority for an EPPO pest risk analysis. The process consists of compiling available information on alien plants according to pre‐determined criteria, and can be run at the EPPO region level, or at a country or local area level. These criteria examine whether the species is alien in the area under study, and whether it is established or not. The criteria used primarily rely on observations in the EPPO region but, if the species is not established, the invasive behaviour of the species in other countries should be investigated, as well as the suitability of the ecoclimatic conditions in the area under consideration. The spread potential, the potential negative impacts on native species, habitats and ecosystems, as well as on agriculture, horticulture or forestry are considered. If the species qualifies as an invasive alien plant of major concern through this first set of questions, the process then investigates the efficiency of international measures (to be justified through a pest risk analysis) to prevent the entry and spread of the species. The second set of questions are designed to determine whether the species is internationally traded or enters new countries through international pathways for which the risk of introduction is superior to natural spread, and whether the species still has a significant suitable area for further spread. If used by several EPPO countries, this prioritization process represents an opportunity to provide consistent country lists of invasive alien plant species, as well as a tool for dialogue and exchange of information.     

Status and trends in the alien flora of Corsica

This article summarizes and analyses some of the data published in Flora Corsica ( Jeanmonod & Gamisans, 2007 ) in order to characterize the alien vascular plant flora of the island. The data analysed focus on different aspects of the alien flora such as diversity (species richness), abundance, life‐forms, vegetation belts, habitats and biogeographical origins. The results show that the alien species richness is currently high, representing 16.5% of the total flora, amongst which 37.5% are naturalized. The penetration of this flora occurs mainly at lower altitudes, and is still weak or absent in the higher altitude vegetation belts whereas it has increased over time within natural closed habitats. Over the last 11 years, the species richness of xenophytes has increased by 18.1%, which corresponds to an increase of 23.0% of the naturalized plants. Moreover, 24.8% of the alien taxa have increased in abundance. A scenario highlighting the trends of the introduced flora, and that includes issues of native biodiversity conservation, is proposed based on the results. The special case of invasive species is also considered, and their exponential increase on Corsica is highlighted. Other aspects of the alien flora, such as its taxonomic spectrum and biogeographical origins, are also analysed and are, whenever possible, compared with those of other geographical regions, particularly from the Mediterranean (Sardinia, Balearic Islands) and Continental Europe.     

庐山外来植物调查研究

[目的]为进一步了解庐山地区现有外来植物现状,掌握庐山外来植物数据,为庐山外来植物管理提供参考依据.[方法]运用线路踏查法进行野外调查并结合相关文献、标本资料,对庐山外来植物种类、生活型、 原产地、引入途径以及外来入侵植物种类进行研究.[结果]庐山外来植物共有89科309属448种:(1)菊科植物种类最多,有69种,约...     

Invasive alien plants in plant health: a review of the past ten years

The International Plant Protection Convention (IPPC) provides the background for National Plant Protection Organisations (NPPOs) to regulate and control invasive alien species that are harmful to plants. This subject was specifically discussed for the first time 10 years ago at IPPC level, and further explored by an IPPC open‐ended working group. The resulting concept was considered at EU level, and the EU Council supported the suitability of the plant health framework for these species, requesting the EU Commission to further analyse the needs for regulatory work in the EU plant health regime. Subsequently the European and Mediterranean Plant Protection Organization (EPPO) started a new working programme. The international conference ‘Invasive alien species and the IPPC’ set a signal for IPPC contracting parties to encourage their NPPOs to enforce actions on invasive alien species. IPPC standards on pest risk analysis (PRA) were adapted so as to include invasive alien species harmful to plants, and a memorandum of cooperation was adopted between the Secretariats of the IPPC and the Convention on Biological Diversity (CBD). At present, the EU Commission, DG Environment is developing a European strategy on invasive alien species. The EU Plant Health Regulatory System is currently subjected to a major evaluation process in which a clearer inclusion of invasive alien species into the system is one of the strategic discussions.     

基于Android和深度学习的外来入侵植物 智能识别系统

我国是遭受外来入侵生物危害最严重的国家之一?目前国内对外来入侵植物的鉴定主要依靠调查人员的经验和专家的人工识别, 存在费时费力和主观性强的问题?针对上述问题, 本文在Android环境下开发了一个实时便捷的外来入侵植物智能识别系统, 由移动客户端APP?云服务器和基于深度学习的外来入侵植物识别模型组成?调查者可以通过手机客户端APP拍摄植物图像, 上传至云服务器, 识别模型会自动识别图像上的植物, 识别结果和防治信息在1~2 s内反馈至用户客户端, 还可以远程请求专家鉴定?该系统对35科135种入侵植物的平均识别率达到85.3%?基于Android的外来入侵植物智能识别系统实现了中国常见入侵植物信息查询?自动识别?入侵植物采集点地图显示和专家远程鉴定等功能, 为野外调查人员提供了一个便捷准确的外来入侵植物自动识别和调查工具?     

Invasive aquatic plants in the aquarium and ornamental pond industries: a risk assessment for southern Ontario (Canada)

An assessment of the invasive risk associated with the establishment and dispersal of plants available in the aquarium and ornamental pond industries in the Greater Toronto area (Canada) was made. In the risk model, sales volumes of individual taxa were used as a proxy for propagule pressure, to assess pathway risk potential. Organism risk potential, the ability to become established and disperse associated with a release, was assessed using an analysis of the biological traits of the species. Discriminant correspondence analysis was used to predict which biological traits were useful in discriminating native plants from alien invasive plants and alien non‐invasive plants. Importantly, a relatively small number of biological traits appear to be useful in predicting whether an alien aquatic plant had the characteristics that would support establishment and/or dispersal in new environments. Aquatic plants distributed by the industries that are cold tolerant, able to propagate by fragments and use a number of dispersal methods are of particular concern as potential invaders. The model identified 11 alien plants in the trade that have a high risk of becoming invasive, and an additional 52 with moderately high risk.     

Is terrestrial plant import from East Asia into countries in the EPPO region a potential pathway for new emerging invasive alien plants?

Pathway analysis represents an effective means of identifying emerging invasive alien species. For plants, a significant number of invasions have been caused by plant species originally voluntary introduced as ornamentals. The pathway analysis for terrestrial ornamental plants imported from East Asia has been undertaken to provide information on the imports and to identify emerging terrestrial invasive alien plants. Data for terrestrial ornamental plants imported from East Asia into Austria, France, Italy, the Netherlands and Turkey was assembled at the genus level. Thousands of species of plants for planting are imported from East Asia in very large volumes. However, despite the fact that the data could only been analyzed at the genus level, it is considered that only a very limited number of taxa would become invasive. The potentially invasive alien species are already widely available in European nurseries and are principally produced within the European Union.