Potential impacts from the release of transgenic plants into the environment

Transformation techniques are making it possible to produce novel and unusual plant phenotypes. When considering the environmental impact of these, it is important to do so in the context of what is known about conventional plant breeding and the thousands of varieties that have been produced during this century and earlier. There has now been over ten years of experience of environmental impact assessment with transgenic plants, and research has enabled that assessment process to be better informed scientifically. There are, however, important challenges for the future. Fundamental changes in plant biology, including enhanced tolerance to stressful environments, may create a class of plants that are different from those that have been produced so far, and there may be lessons to be learnt from the experience worldwide of the release of exotic species into different countries. Scale-dependent effects of transgenic plants in agriculture can only effectively be measured by large scale production and monitoring. The monitoring process presents a number of challenges to provide oversight that is meaningful and helpful in assessing environmental impact. The international transboundary movement of transgenic plants is already a reality, and it is important that our environmental impact assessments take this possibility into account. This includes both intentional transboundary movement, through trade of commodity crops, but also unintentional transboundary movement, including the possibility of seeds being moved by animals, by transportation and by humans across the world. There are some major challenges in devising agricultural strategies for the transgenic crops that will become available in the future. The responsibility for developing agricultural strategy rests at a number of levels. To achieve this, it will be necessary to have effective dialogue between the regulatory authorities, the plant breeding and agrochemical industries, and the farming industry. There are already encouraging moves in this direction and hopefully this will continue.     

四种与福寿螺(Ampullaria gigas)同源地入侵植物的杀螺效果

实验室内观察了福寿螺在其主要危害对象水稻,及与其同源地的入侵植物五爪金龙、马缨丹、胜红蓟和蟛蜞菊5种植物新鲜叶片间聚集数量差异,结果显示:15min后福寿螺在距离其约75cm的5种植物叶片聚集数产生了显著的差异,但75min内福寿螺在5种植物叶片间聚集的数量不稳定,75min后的聚集数趋于稳定,5种植物叶片上聚集福寿螺数由多到少顺序为蟛蜞菊、马缨丹、水稻、胜红蓟和五爪金龙.福寿螺取食水稻幼苗的量较大,显著高于取食另4种植物新鲜叶片的量,福寿螺取食4种与其同源地植物叶片量由小到大的顺序为:五爪金龙、蟛蜞菊、胜红蓟和马缨丹.不同浓度4植物乙醇提取物水溶液对福寿螺毒杀作用差异显著,乙醇提取物饱和水溶液致福寿螺100%死亡的时间由短到长的顺序为:五爪金龙48h,蟛蜞菊72h,胜红蓟和马缨丹均为96h,按常规施用量化学农药密达100%毒杀福寿螺的时间为118h.综合结果表明五爪金龙具有开发出既能有效防治福寿螺又不影响水稻生长和稻田环境材料的潜力.     

Biological control of invasive plants through collaboration between China and the United States of America: a perspective

For more than 100 years, classical biological control of invasive plants through screening, introducing and releasing of host-specific natural enemies from native regions has been regarded as one of the promising approaches to the management of invasive plants. Many invasive plants in the United States of America are native to China, and vice versa. China and the USA also share a number of invasive plant species, including water hyacinth (Eichhornia crassipes), alligator weed (Alternanthera philoxeroides) and cordgrass (Spartina spp.). Collaboration between the two countries on biological control benefits both the nations by reciprocal opportunities to research and exchange natural enemies, by exchanging information on common invasive species, and by providing training for students and professionals. Here we review the history of collaboration between China and the US on biological control of more than 20 invasive plants. Current collaborative projects associated with four plant species, Polygonum perfoliatum L., Trapa natans L. Pueraria montana (Lour.) Merr. var. lobata and Ailanthus altissima (Mill.) Swingle, are also covered. We prioritize 14 invasive plants as targets for future collaborative biological control based on information on their importance in introduced areas, natural enemy records, and their potential biocontrol risk to introduced ecosystems. They are: Ampelopsis brevipendunculata, Celastrus orbiculatus, Dioscorea oppositifolia, Euonymus alata, Euonymus fortunei, Ligustrum sinense, Melia azedarach, Paulownia tomentosa, Sapium sebiferum and Ulmus pumila for the US, as well as Spartina alterniflora, Ambrosia artemisiifolia, Ambrosia trifida and Solidago canadensis for China. In addition, we emphasize that we must very carefully consider any potential non-target effect when we intend to introduce and release new natural enemies. We anticipate that the high priority both countries have placed on control of invasive plants will stimulate increasing collaboration on biological control.     

协同分布式实验2.0 (CDE 2.0):生态学野外研究新方法

全球野外实验网络是近年来兴起的生态学实验方法,产生了“协同分布式实验”(CDE)、“分布式协作实验”(DCE)的野外实验网络和英国生物学记录中心(BRC)的野外观察网络等具体方法,但均存在尺度小、周期短或数据偏差问题.野外实验网络的协议设计应秉持实验优于观察测量、数据数量优于数据质量和尺度优于操作的原则.综合上述方法,本研究提出利用公众科学(citizen science)获得大范围、多尺度和长周期的数据,采用环境因子作为协变量对公众参与者的实验数据集进行验证后,将其作为后验概率与作为主观概率的生态学家实验数据集进行比对,以完成数据有效性验证,克服公众参与者数据质量瑕疵,并提出了相应的统计学模型.讨论了生态学实验数据中应用先验概率、先验与后验概率的逻辑关系以及后验概率发现演化过程新关系的可能性.这种方法更符合统计学采样规范,并增加了大尺度时空的样本量.该方法有望为生态学研究所寻找的一般性理论提供方法支持,新方法可称之为“协同分布式实验2.0”(CDE 2.0).     

利用昆虫携带的花粉初探西藏入侵植物印加孔雀草在当地传粉网络中的地位

入侵植物在新生境中成功定殖后, 通过利用当地传粉昆虫促进繁殖可以更好地保证种群的扩张, 但是入侵植物在当地传粉网络中的角色和地位仍不是很清楚。本文利用西藏近年发现的入侵植物印加孔雀草(Tagetes minuta), 分析其访花昆虫所携带的植物花粉种类, 构建了植物花粉-传粉者网络, 探讨印加孔雀草快速入侵和扩张的可能机制。结果表明印加孔雀草为泛化传粉系统, 共有13种昆虫访花, 其中12种携带有印加孔雀草花粉, 所有花粉中印加孔雀草花粉数量占比为89.89%。12种印加孔雀草传粉昆虫中, 4种泛化传粉昆虫(1种蜂、2种食蚜蝇和1种蝇)是其主要传粉昆虫。本研究揭示印加孔雀草在较短时间内已经成功利用多种当地泛化传粉昆虫为其授粉, 已顺利融入当地的传粉网络, 今后需要更加重视对印加孔雀草的防控。     

四种与福寿螺(Ampullaria gigas)同源地入侵植物的杀螺效果

实验室内观察了福寿螺在其主要危害对象水稻,及与其同源地的入侵植物五爪金龙、马缨丹、胜红蓟和蟛蜞菊５种植物新鲜叶片间聚集数量差异,结果显示:15min后福寿螺在距离其约75cm 的5种植物叶片聚集数产生了显著的差异,但75min内福寿螺在5种植物叶片间聚集的数量不稳定,75min后的聚集数趋于稳定,5种植物叶片上聚集福寿螺数由多到少顺序为蟛蜞菊、马缨丹、水稻、胜红蓟和五爪金龙。福寿螺取食水稻幼苗的量较大,显著高于取食另4种植物新鲜叶片的量,福寿螺取食4种与其同源地植物叶片量由小到大的顺序为：五爪金龙、蟛蜞菊、胜红蓟和马缨丹。不同浓度4植物乙醇提取物水溶液对福寿螺毒杀作用差异显著,乙醇提取物饱和水溶液致福寿螺100%死亡的时间由短到长的顺序为：五爪金龙48h, 蟛蜞菊72h, 胜红蓟和马缨丹均为96h,按常规施用量化学农药密达100%毒杀福寿螺的时间为118h。综合结果表明五爪金龙具有开发出既能有效防治福寿螺又不影响水稻生长和稻田环境材料的潜力。     

Callosciurus squirrels: worldwide introductions,ecological impacts and recommendations to prevent the establishment of new invasive populations

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Ecological and socio‐economic impacts of invasive water hyacinth (Eichhornia crassipes): a review

1. Water hyacinth (Eichhornia crassipes) is one of the world’s most invasive aquatic plants and is known to cause significant ecological and socio‐economic effects. 2. Water hyacinth can alter water clarity and decrease phytoplankton production, dissolved oxygen, nitrogen, phosphorous, heavy metals and concentrations of other contaminants. 3. The effects of water hyacinth on ecological communities appear to be largely nonlinear. Abundance and diversity of aquatic invertebrates generally increase in response to increased habitat heterogeneity and structural complexity provided by water hyacinth but decrease due to decreased phytoplankton (food) availability. 4. Effects of water hyacinth on fish are largely dependent on original community composition and food‐web structure. A more diverse and abundant epiphytic invertebrate community may increase fish abundance and diversity, but a decrease in phytoplankton may decrease dissolved oxygen concentrations and planktivorous fish abundance, subsequently affecting higher trophic levels. 5. Little is known about the effects of water hyacinth on waterbird communities; however, increases in macroinvertebrate and fish abundance and diversity suggest a potentially positive interaction with waterbirds when water hyacinth is at moderate density. 6. The socio‐economic effects of water hyacinth are dependent on the extent of the invasion, the uses of the impacted waterbody, control methods and the response to control efforts. Ecosystem‐level research programmes that simultaneously monitor the effects of water hyacinth on multiple trophic‐levels are needed to further our understanding of invasive species.     

外来种刺槐叶瘿蚊的重要寄生性天敌——刺槐叶瘿蚊广腹细蜂在中国的地理分布

刺槐叶瘿蚊广腹细蜂Platygaster robiniae Buhl and Duso(膜翅目:细蜂科)是我国外来有害生物刺槐叶瘿蚊Obolodiplosis robiniae(Haldeman)(双翅目:瘿蚊科)十分重要的寄生性天敌,为卵-幼虫跨期寄生蜂,专化性强,在自然抑制害虫虫口密度中起着非常重要的作用。为摸清刺槐叶瘿蚊广腹细蜂在我国的地理分布,探讨其与刺槐叶瘿蚊的相互关系,本文根据寄主刺槐叶瘿蚊在我国的分布范围,采用踏查的方法,对全国17个省、市、自治区的29个地区进行了调查。结果显示,刺槐叶瘿蚊广腹细蜂在其寄主分布区都有分布,分布范围在26°35.451′-43°53.482′N,103°51.816′-125°15.969′E,海拔4-1 097 m。     

Vulnerability of an Australian anuran tadpole assemblage to the toxic eggs of the invasive cane toad (Bufo marinus)

The invasion of cane toads (Bufo marinus) across tropical Australia has fatally poisoned many native predators; the most frequent victims may be tadpoles of native frogs, which die when they consume the toxic eggs of the toads. Field studies have documented high and species‐specific mortality of tadpoles following toad spawning. To clarify the determinants of tadpole vulnerability, we conducted 1593 laboratory trials in which single tadpoles were exposed to 10 toad eggs, either with or without an alternative food source (lettuce). At least some tadpoles within all 15 species tested consumed toad eggs. Interspecific variance in survival rates (from 0 to >70%) was driven by feeding responses not by physiological tolerance to toxins: almost all native tadpoles that consumed eggs died rapidly. Tadpole mortality was decreased by the presence of an alternative food source in four species, increased in two species, and not affected in seven species. In three of four taxa where we tested both small (early‐stage) and large (late‐stage) tadpoles, both mean survival rates and the effects of alternative food on survival shifted with tadpole body size. Trials with one species (Limnodynastes convexiusculus) showed no significant inter‐clutch variation in feeding responses or tolerance to toxins. Overall, our data show that cane toad eggs are highly toxic to native anuran tadpoles, but that whether or not a tadpole is killed by encountering toad eggs depends upon a complex interaction between the native anuran's species, its body size, and whether or not alternative food was present. In nature, larval vulnerability also depends upon the seasonal timing and location of spawning events, and habitat selection and foraging patterns of the tadpoles. Our results highlight the complexity of vulnerability determinants, and identify ecological factors (rather than physiology or feeding behaviour) as the primary determinants of cane toad impact on native tadpoles.     

Detecting the impact of invasive species on native fauna: Cane toads (Bufo marinus), frillneck lizards (Chlamydosaurus kingii) and the importance of spatial replication

An understanding of which native species are severely impacted by an anthropogenic change (such as the arrival of an invasive species) and which are not is critical to prioritizing conservation efforts. However, it is difficult to detect such impacts if the native taxa exhibit strong stochastic variations in abundance; a ‘natural’ population decline might be wrongly interpreted as an impact of the invader. Frillneck lizards (Chlamydosaurus kingii) are large iconic Australian agamids, and have been reported to decline following the invasion of toxic cane toads. We monitored three populations of the species in the savanna woodland of tropical Australia over a 7‐year period bracketing toad arrival. One population crashed, one remained stable and one increased. Hence, studies on any single population might have inferred that cane toads have negative, negligible or positive effects on frillneck lizards. With the benefit of spatial replication, and in combination with observations of prey choice by captive lizards, our data suggest that invasive cane toads have had little or no effect on frillneck abundance.     

Impacts of eggs and tadpoles of the invasive cane toad (Bufo marinus) on aquatic predators in tropical Australia

Invasive species affect native ecosystems in a variety of ways, and the magnitude of impact may depend upon many factors. In an invading species such as the cane toad (Bufo marinus), the multiphasic life history creates a potential for impact to differ between life history stages. Previous research on the impact of cane toads in Australia has focused on fatal poisoning of predators that ingest terrestrial stages of the toad, but aquatic stages (eggs, larvae) are toxic also. We exposed nine native Australian fish species and one native Australian turtle species to the eggs and larvae of toads. Strong species differences were evident, both in palatability (propensity to attack the egg or larva), and in subsequent responses (e.g. taste and reject the item, vs. ingest it). Toad eggs were less likely than toad tadpoles to be attacked, but also less likely to be rejected before ingestion (probably because the non‐toxic jelly coat masks the presence of toxins in the ovum). As a result, predators were far more likely to be killed by ingesting toad eggs than toad tadpoles. Fortuitously, the spatial and temporal availability of toad egg masses restricts encounter rates with predators, so that overall ecological impact may be low despite the high vulnerability of a fish or turtle that encounters such an egg mass. Understanding such ontogenetic shifts in the nature of interactions and magnitude of impact is crucial if we are to understand the overall ecological impact of invasive species.     

异色瓢虫生物生态学研究进展

原产于亚洲的异色瓢虫[Harmonia axyridis Pallas(Coleoptera:Coccinellidae)]是最重要的捕食性瓢虫种类之一,被广泛应用于农林业害虫的生物防治.本文综合分析了国内外近几十年对异色瓢虫的研究成果,对其重要的生物学及生态学特性进行了归纳,主要涉及生活史、繁殖行为及策略、捕食行为和自残行为等,分析了相关研究对其应用前景的影响.基于异色瓢虫的人工饲养、农药交互作用以及入侵生态影响等的总结,提出了预防异色瓢虫造成生态不平衡的具体措施.     

我国入侵植物多样性的区域分异及其影响因素——以74个地区数据为基础

以我国74个地理单位282种外来入侵植物的分布和环境数据为基础,应用除趋势对应分析、典范对应分析和回归分析方法,探讨了我国境内入侵植物区系组成、地理分布格局及其影响因素。主要结果如下:(1)我国74个地区共有282种外来入侵种,出现频率相对较高的外来入侵种是小飞蓬(Conyza canadensis)、刺苋(Amaranthus spinosus)、一年蓬(Erigeron annuus)、空心莲子草(Alternathera philoxeroides)、土荆芥(Chenopodium ambrosioides)、圆叶牵牛(Pharbitis purpurea)、曼陀罗(Datura stramonium)、皱果苋(Amaranthus viridis)、裂叶牵牛(Pharbitis nil)、反枝苋(Amaranthus retroflexus)、三叶鬼针草(Bidens pilosa)、凤眼莲(Eichhornia crassipes)等;(2)菊科(Compositae,67,种数)、禾本科(Gramineae,32)、豆科(Leguminosae,29)、苋科(Amaranthaceae,23)、旋花科(Convolvulaceae,13)是我国境内含入侵种最丰富的5个科,共计有164种,占我国入侵植物总数的58.16%;(3)我国外来入侵植物主要源自于热带美洲、北美洲、欧洲、地中海-西亚和中亚、非洲和南亚;(4)外来入侵植物多样性在我国的区域分异明显,热带-南亚热带、中(北)亚热带和温带三大区域的入侵种组成有较大差异:马缨丹(Lantana camara)、含羞草(Mimosapudica)、胜红蓟(Ageratum conyzoides)、刺苋、小飞蓬、飞扬草(Euphorbia hirta)、五爪金龙(Ipomoea cairica)、空心莲子草、三叶鬼针草和金腰箭(Synedrella nodiflora)是热带-南亚热带区域中出现频率最高的前10种入侵植物;中亚热带和北亚热带区域出现频率最高的入侵种分别是一年蓬、小飞蓬、刺苋、土荆芥、北美独行菜(Lepidium virginicum)、美洲商陆(Phytolacca americana)、牛筋草(Eleusine indica)、紫茉莉(Mirabilis jalapa)、空心莲子草和三叶鬼针草;温带区域出现频率最高的是反枝苋、小飞蓬、圆叶牵牛、一年蓬、野西瓜苗(Hibiscus trionum)、杂配藜(Chenopodium hybridum)、苦苣菜(Sonchus oleraceus)、野燕麦(Avena fatua)、曼陀罗和皱果苋;(5)年降雨量、年均温度、年极端低温、无霜期和年均积温是影响我国外来入侵种空间分布格局的主要气象因素,年极端高温和年日照时数的影响相对较小;人口密度和交通密度对入侵种的地理分布也均有很大的影响;(6)随着年均温度、无霜期、人口密度、交通密度、年极端低温、年均降雨量和年积温的增加,外来入侵植物的种数呈线性增加,随着纬度的增加,种数则呈线性递减,种数与这8个环境因素间的关系达到极显著的水平;(7)不同地理来源的外来入侵种在我国的分布主要受纬度、年降雨量、年均无霜期、年均温度、交通密度、年极端低温和年均积温的影响。由于外来入侵种在我国分布呈现明显的区域分化,因此,应用建立具有区域特点的外来植物入侵风险评估系统。     

Predicting socio‐economic and biodiversity impacts of invasive species: Red Imported Fire Ant in the developing western Pacific

Effective biosecurity and pest management are fundamental to sustainable development. Invasive ants pose significant risks to the environment and economy, which are well‐managed by biosecurity agencies in developed countries. However, a comprehensive view of the potential impacts of invasive ants in developing Pacific Island Countries and Territories (PICTs) is lacking. We quantified the potential costs of the Red Imported Fire Ant (Solenopsis invicta Buren) across multiple sectors using an extrapolation analysis. Overall, we estimated that the impacts of Red Imported Fire Ant on developing PICTs could amount to over USD 329 million annually, corresponding to approximately 0.7% of combined GDP. Over half of the costs were predicted to result from impacts on the agriculture sector, a major source of employment and subsistence. We found that over 350 highly threatened species could be at risk from Red Imported Fire Ant. We would expect countries with Least Developed Country status and relatively low GDP to be least able to respond to an incursion of these ants, and as a result the costs could be higher than we have extrapolated. Red Imported Fire Ant could therefore potentially have considerable impact on the on‐going development of the region.     

Impact of the invasive ant Wasmannia auropunctata (Formicidae: Myrmicinae) on local ant diversity in southern Cameroon

The little fire ant, Wasmannia auropunctata Roger, is one of the world's most destructive invasive ants. It has been present in Cameroon for more than four decades, but its impact on local ant diversity is not known. We studied impact of W. auropunctata in three disturbed habitats located in rural and urban areas. We monitored ant diversity in both invaded and noninvaded zones in each area using a combination of three sampling methods: bait, pitfall traps and visual catch in quadrat. We collected 28 species in urban area and 64 in rural area. In invaded zone, W. auropunctata made up 97.72% and 99.96% of all ant fauna and ant species richness decreased to 7 and 2 in urban and rural area, respectively. In accordance with others findings in introduced environments, the presence of W. auropunctata has severely reduced abundance and richness of local ant species in both urban and rural environments in Cameroon. Measures should therefore be put in place to prevent its introduction in natural environment as forest reserves and natural parks.