外来植物入侵机制研究进展

探讨了外来种的概念及外来植物入侵的过程 ,并由入侵过程的影响因素出发 ,从外来植物本身的特性、外来种与土著种的相互作用、初始入侵种群参数以及新栖息地环境的可入侵力等方面综述了近年来有关外来植物入侵机制的研究进展。指出外来植物入侵机制极为复杂 ,早期推测中的一般通用模式已不适用 ;深入研究外来植物的入侵机制 。

河北省外来入侵植物的调查分析

通过对河北外来入侵植物的调查,报道外来入侵植物种类并对外来入侵植物的原产地、引入途径、危害程度等进行分析,结果表明:河北目前有63种外来入侵植物,隶属于20科46属。其中①菊科和禾本科为优势科,所含种数分别为17种和9种,占外来入侵植物总种数的41.27%;②来自美洲的植物31种,占外来入侵植物总种数的49.2%;来自于欧洲的外来入侵植物有10种,占总种数的15.87%;③34种是人为有意引进,占外来入侵植物总种数的53.97%;26种是属于无意引进造成的,占总种数的41.27%;④52种是一般性杂草,占外来入侵植物总种数的82.54%;恶性杂草9种,占总种数的14.29%。

衡山县外来入侵生物危害现状与防控对策

衡山县已发现空心莲子草、福寿螺等8种外来入侵生物。在分析衡山县外来入侵生物发生、危害及防控现状的基础上,提出强化宣传与监督执法、开展封锁与定点铲除、加强防控技术研究与推广、变害为益、综合利用等防控对策与建议。

成都市外来入侵物种调查研究

对成都市外来入侵物种的种类、数量、分布和危害进行了调查,初步发现有蔗扁蛾(香蕉蛾)Opogona sacchari(Bojer)、大瓶螺(福寿螺、苹果螺、雪螺)Pomacea canaliculataSpix、空心莲子草(水花生、喜旱莲子草)Alternan-thera philoxeroides(Mart.)Griseb、凤眼莲(水葫芦、凤眼蓝)Eichhornia crassipes(Mart.)Solms、牛蛙Rana catesbei-anaShaw等。提出了引入扩散原因及危害分析、防除方法,近期可能入侵成都市的外来物种,防治外来入侵物种工作存在的问题。

紫茎泽兰入侵对土壤肥力特征的影响及其动态研究

采用室内分析方法,测定了紫茎泽兰入侵不同年份的种群根际土壤N、P、K养分状况及其季节动态,比较分析了紫茎泽兰入侵对土壤养分影响在其入侵过程中的意义。结果表明,紫茎泽兰的入侵显著提高了根际土壤NH4+-N、NO3--N、全钾和有效钾的含量,降低了土壤全磷和有效磷的含量,而对土壤全氮含量没有明显影响。不同入侵种群根际土壤养分含量随季节变化的趋势为:土壤NH4+-N上升,NO3--N降低,有效磷和全钾先升后降,而全氮和全磷无明显季节变化,这可能是在年内生长过程中,紫茎泽兰能够通过活化土壤含磷化合物来满足自身生长的需求,对土壤NO3--N和有效钾的吸收利用较多,而对土壤NH4+-N的需求较少所致。紫茎泽兰入侵对根际土壤不同肥力特征的正负影响及其自身的适应特性可能是其能够入侵成功和快速扩张蔓延的生态机制之一;应用不同功能型植物建立生态群落以充分利用土壤养分资源,将在紫茎泽兰的生态控制和其入侵地的生态修复中起到较好的效果。

紫茎泽兰与黑麦草苗期相对竞争力和生长特征的研究

为探究替代物种黑麦草(Lolium perenne)抑制外来入侵杂草紫茎泽兰(Eupatorium adenophorum)的潜力,采用de Wit取代系列设计,在野外小区内设置3水平多年生黑麦草栽植时间、4水平种植密度以及3水平混种比例等不同种植处理,于12周后收获,分别测量黑麦草与紫茎泽兰的地上生物量和地下生物量,用单株相对产量分析其竞争力。结果表明,种植密度、混种比例和黑麦草栽植时间显著影响紫茎泽兰的地上生物量,紫茎泽兰的竞争力在低种植比例情况下,随黑麦草栽植时间的推迟而明显增强,随种植密度的降低而增强。种植密度、混种比例、黑麦草栽植时间以及这些因素的互作等对黑麦草的地上生物量与地下生物量均具有显著影响;栽植时间越晚、密度越大,黑麦草的竞争力就越弱(尽管不存在直线关系)。在大多数种植处理条件下,紫茎泽兰经历的种间竞争明显大于种内竞争,表现出较弱的竞争力;而黑麦草在与紫茎泽兰同时栽植的情况下,经历的种内竞争大于种间竞争,表现出较强的竞争力。

Investigation and Risk Assessment of Alien Invasive Plants in Riparian Zone of Dongjiang River

[Objective] The aim was to conduct investigation and risk assessment of the alien invasive plants in riparian zone of Dongjiang River.[Method] The field survey was carried out by the combination methods of sampling plots investigation and route survey,and the whole Dongjiang River was covered.52 sampling points were set in the main streams,and 87 sampling points in tributaries streams,624 quadrats were set in total;multi-index comprehensive evaluation method was adopted for the risk assessment with 6 first-level indexes and 25 second-level indexes.[Result] Through the investigation on the riparian zone of Dongjiang River for 2 years,51 species of alien invasive plants were found,belonging to 17 families and 38 genera.The risk level assessment results of these 51 species showed that 18 species,such as Ageratum conyzoides,belonged to high-level risk with over 60 points;26 species,such as Chenopodium ambrosioides,were between 30 and 60 points which belonged to middle-level risk;7 species,such as Paspalum dilatatum,with less than 30 points belonged to low-level risk.[Conclusion] Basic data on the protection,water environmental management and functional zoning of riparian zone of Dongjiang River were provided.

A Study on Alien Invasive Plants from the Interactive Mechanism between Species Niche and Material/Energy Flow

[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic mechanism of alien plants invasion.[Result]Most of the invasive plants have not been explicitly defined and their effective control methods not brought forward.[Conclusion]Overrun of alien invasive plants depends on whether the niche of a species could be continuously met at spatial level.Based on this we put forward corresponding control measures,proposed an assumption to establish a cylinder-network model and discussed the definition of alien invasive plants.

Study on the Allelopathic Effects of Alien Invasive Species Cenchrus echinatus on Seed Germination and Seedling Growth of Solanaceae Crops

[Objective] This study aimed to investigate the potential ecological dam- ages of alien invasive species Cenchrus echinatus. [Method] By using seed germi- nation method, the effects of different concentrations of C. echinatus aqueous extracts on seed germination and seedling growth of three Solanaceae crops were investigated. [Result] After incubated for 5 d, no significant differences were observed in germination speed indices of Lycopersicum esculentum seeds between aqueous extract groups and control groups; germination speed indices of Solarium melongena seeds were significantly reduced with the increasing concentration of Cenchrus echinatus aqueous extracts; however, Capsicum frutescens seeds in various groups were not germinated. After incubated for 7 d, root lengths of Lycopersicum esculentum seedlings were inhibited with the increasing concentration of Cenchrus echinatus aqueous extracts, while stem lengths and comprehensive allelopathic effects were promoted; germination rates of Solanum melongena seeds in various groups were all significantly lower than control groups; root length, stem length and comprehen- sive allelopathic effects in higher concentration groups were inhibited; germination rates of Capsicum frutescens seeds were significantly inhibited, and those in the highest concentration group were not generated. After incubated for 14 d, all indica- tors of Solanum melongena were significantly inhibited; various indicators of Capsicum frutescens in the highest concentration group were significantly inhibited. [Conclusion] The sensitivity of three Solanaceae crops to Cenchrus echinatus aqueous extracts presented an overall order of Solanum melongena 〉 Capsicum frutescens 〉 Lycopersicum esculentum, suggesting that Cenchrus echinatus can to some extent inhibit the growth of several crops, which should be strictly prevented and controlled in agricultural production.

Biodiversity and Invasibility: Distribution Patterns of Invasive Plant Species in the Himalayas, Nepal

Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low native diversity' vs. ‘high native diversity', is supported by the regional distribution patterns of invasive plant species in the Himalayas,Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high.Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend.Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that ‘high native diversity' supports or facilitates invasive plant species. Further, it indicates that nativeand invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors.

Zoospore-derived monoecious gametophytes in Undaria pinnatifida(Phaeophyceae)

The annual life cycle of the brown seaweed Undariapinnatifida （Harvey） Suringer comprises a macroscopic diploid sporophyte stage and a microscopic haploid gametophyte stage. In 2011, an unusual zoospore-derived monoecious gametophyte isolate （designated as line 10-5-3） of U. pinnatifida was observed. To understand this phenomenon, a comprehensive screening of eighty-two previously identified male gametophyte cultures, isolated from three randomly selected cultivars （lines 10, 7, and 5） was performed. Thirty-six of the isolates developed both antheridia and oogonia on the same filamentous fragment in a standard gametogenesis test （SGT： 18℃, 60 umol photons/（m2.s））. Selfing of the monoecious gametophyte or crossing it with a normal male gametophyte both gave rise to morphologically normal sporophytic offspring. However, crossing resulted in a much higher fertilization rate （89.7%）. The hybrid and selfed sporophytic offspring were grown to maturity in flow tanks at an ambient temperature of 10-18℃ over a period of 69 days. Active zoospores were released from both types of mature sporophylls. The majority of these developed into male gametophytes, while 15%-20% developed into the observed monoecious structures on the same filament. Using PCR amplification it was found that all the monoecious gametophyte isolates and the sporophytic offspring resulting from the selfing and crossing lacked the femalelinked microsatellite sequence （a part of the locus Up-AC-2A8, GenBank accession No. AY738602.1）, indicating their male nature. U.pinnatifida is an invasive species in some regions and the implications of the above findings for this species in nature are briefly discussed.

Evaluation of Extracts of Native and Non-Native Plant Species for the Suppression of Cogongrass （Imperata cylindrica L.）

Effects of the extracts of muhly grass （Muhlenbergia capillaries Lam.）, chenopodium （Chenopodium ambrosioides L.） and black walnut （Juglans nigra L.） on the growth of cogongrass （Imperata cylindrica L.） were studied. None purified extracts from these plant species were used to evaluate survival, shoot and root growth of cogongrass. Results of plant species extracts on the production of roots, shoot and rhizomes of cogongrass genets and ramets were determined on a weekly basis. The extracts significantly reduced the growth and survival of cogongrass when compared to the control. Results indicated that for the in vivo studies, chenopodium extracts, black walnut and muhly grass extracts reduced growth, root and shoot biomass of cogongrass by 50 %, 30 % and 41% respectively, compared to control at 8 weeks after planting. These studies indicated plant species with potential for the biological control of cogongrass, an invasive species in the Gulf Coast States.

Red Palm Weevil, Rhynchophorus ferrugineus （Olivier）： Economic Importance, Biology, Biogeography and Integrated Pest Management

The Red Palm Weevil （RPW）, Rhynchophorus ferrugineus （Olivier）, （Coleoptera, Curculionidae, Rhynchophorinae）, is an invasive species that is originated from Southeast Asia. It has.invaded Middle East and several countries of the Mediterranean Basin during the last three decades where it attacks palm trees. During the last three decades, multiple introductions of RPW to the Middle East, Europe and Caribbean （Island of Curacao, Netherland Antilles）, Lebanon and United States of America （Laguna Beach, Orange County, California） （USA） have occurred and the RPW is now a serious pest of many palm species. Duration of all life parameters varies significantly where the entire life cycle takes about 45 to 298 days. Different artificial diets were developed and were tested for mass rearing of RPW. Control of RPW is difficult due to the concealed nature of the life cycle of the pest. Integrated Pest Management （IPM） strategy has been applied successfully to deal with RPW problem. The IPM strategy consists of various preventive and curative methods; those methods were categorized in nine categories in this review. The main objective of this work was to review the existing knowledge on RPW＇s different aspects, with an ultimate aim of revealing the actual situation of the research on RPW.

Preliminary Study on Geographical Variation of Cytochrome b gene and ITS2-rDNA among Populations of Rhynchophorus ferrugineus

The Red Palm Weevil （RPW）, Rhynchophorus ferrugineus （Olivier）, （Coleoptera, Curculionidae, Rhynchophorinae）, is an invasive species that is originated from Southeast Asia. It has invaded Middle East, several countries of the Mediterranean Basin, Caribbean （Island of Curacao, Netherland Antilles）, Lebanon and United States of America （Laguna Beach, Orange County, California） during the last three decades where it attacks palm trees. This study investigated the geographical variation among geographic populations of RPW collected from twelve invaded countries using cytochrome b （Cytb） and ITS2 partial sequences. The comparison among the Cytb sequences resulted in three different haplotypes designated as HB 1 to HB3. The three haplotypes were subdivided into two phylogenetic groups according to their geographic positions： （1） the ＂Multi-Continent＂ group containing HB 1 haplotype detected in eight populations belonging to three different Continents such as Africa-Egypt, Asia-Kingdom of Saudi Arabia and Turkey and Europe-Spain, Italy, Greece, Cyprus and France, and （2） the ＂Asian＂ group includes four populations from Iran （harboring HB2 haplotype）, Pakistan, UAE, and Oman （harboring HB3 haplotype）. This mitochondrial pattern of genetic diversity suggests that the tested RPW populations subdivided genetically into different sub-populations under the influence of genetic drift. According to these results we concluded that the twelve studied RPW populations are originating from different source populations in the RPW area of origin.

乳化炸药线型切割器对薄壳弹药销毁效果的数值模拟研究

针对目前的弹药销毁状况,为了减轻直接爆破的环境压力,利用理论分析及数值模拟的方法,首先对设计的简易乳化炸药线型切割器的药型罩材料进行确定,数值模拟表明:铝质药型罩所形成的射流侵彻能力要比紫铜材质的提高28%,而后利用ANSYS数值模拟得出该切割器最佳炸高为15 mm。最后对乳化炸药线型切割器切割薄壳弹药的过程进行数值模拟,证明该切割器可以达到切去弹药外壳而不产生剧烈爆轰及高速破片的效果。

Mutagenic Effect of Three Invasive Species through Allium Cepa Bioassay

Invasive alien species are a global threat to biodiversity that affects protected areas around the world. The occupation of new environments by these plants is a problem to be solved and it is essential to investigate all the aspects that allow this successful to find solutions to this question, such as its mutagenic effects. Thus, this study aimed to evaluate the mutagenic effect of leaves extracts of Acacia mangium Willd, Artocarpus heterophyllus Lam and Eriobothrya japonica （Thunb.） Lindl through Allium cepa bioassay. For this, A. cepa seeds were submitted to continuous and discontinuous （acute and chronic） treatments in medium with water （negative control） or four concentration of each extract （1, 5, 10 and 50 mg/mL）. The mitotic index was affected at all concentrations of three extracts tested in all treatments, continuous and discontinuous. Aneugenic effects were not related to any treatment tested. E. japonica extract induced clastogenic effects at 1, 5 and 10 mg/mL in continuous treatment, 5 and 10 mg/mL in acute discontinuous treatment and at 10 mg/mL in chronic discontinuous treatment. Clastogenic effect was also observed at 10 mg/mL ofA. heterophyllus extract in continuous and acute discontinuous treatments.

Tests to evaluate the ecological impact of treated ballast water on three Chinese marine species

Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships' Ballast Water and Sediments, members of the International Maritime Organization(IMO) must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels: Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.

Invasion and Morphological Variation of the Non- Indigenous Barnacle Chthamalus challengeri(Hoek, 1883) in Yangshan Port and its Surrounding Areas

Invasive species generally possess unique characteristics that allow them to survive the invasion process in order to es- tablish and spread in new habitats. Successful invaders must resist both physical and physiological stresses associated with the changing environment. A common littoral barnacle, Chthamalus challengeri Hoek, 1883 （Crustacea, Cirripedia）, which is native to Japan, South Korea and northern China, has become established in the high-littoral zone adjacent to Yangshan Port, Shanghai, China. A comparison of the morphology of Chthamlus species from Zhoushan archipelago with previous description indicates the occur- rence of C. challengeri. The new immigrant becomes a dominant species in certain high-intertidal habitats of the adjacent area to of Yangshan Port. C. challengeri was found in part of sampling sites in Zhoushan in 2010; however, it dispersed to all the eleven sam- piing sites in 2012. Densities of C.challengeri had increased over 10 times in the last 2 years, with the highest mean value reaching 39533 ± 6243 ind. m-2 in the new habitat. The specific ratios of both operculum area （Sa） to base area （SA） and average height of pa- rietal plates （H） to length of base （L） revealed that C. challengeri displays morphological changes to resist stronger currents in the new habitats for invasion.

Status, Impact and Management of Certain Alien Plant Pests Proven to Be Invasive to Thailand＇s Ecology

Introduction of foreign plants and animals into Thailand＇s ecology has a long history, some arrived accidentally and others had a purpose. As global commerce increases, the issue of invasive alien species has become more urgent in Thailand. These agents are increasingly seen as a threat not only to biodiversity and ecosystem, but also to economic development and human well-being. They reduce yields of agricultural crops, forests and fisheries, decrease water availability, cause costly land degradation, block transport routes and contribute to the spread of disease. It is clear that since trade will not stop, dangerous alien species need to be controlled and managed and the strategies and control measures are to prevent, eradicate, contain, or effectively control the invaders. Implementation of these measures requires appropriate legislation, regulation and procedures. The impact of some invasive alien pests and their management on the agricultural sector of Thailand are presented.

Uses of Invasive Alien Plant Species in Rema-Kalenga Wildlife Sanctuary of Bangladesh

An exploratory survey was conducted on the uses and role of invasive alien species(IAS) to local livelihoods in the Rema-Kalenga Wildlife Sanctuary in the northeastern hilly region of Bangladesh.Vegetation was sampled in 50 quadrates,each 10 m×10 m,and 25 line transects,each 50 m×20 m,through a combination of random and systematic sampling.Group discussions were also arranged with fifty local inhabitants(17 % of the total inhabitants) to learn the various uses of IAS.A total of 17 alien plant species belonging to 10 different families,of which Leguminosae constitutes the highest number(5 species),include tree(53%) followed by herb(12%),shrub(12%) and others(weed,climber and palm).The majority of the identified species were found to be used for fuel,followed by timber production,medicinal or curative uses,fodder,and many others.In addition to providing various forest products,alien tree species planted in forest plantation help provide many vital ecosystem services such as soil amelioration through nitrogen fixation.It is true that the alien species have some negative impacts on local ecosystems,and not all of them are harmful.Therefore,a national programme must be initiated to distinguish the harmful from the harmless species and to identify the uses and impacts of the former and latter.