尼罗罗非鱼早期发育形态及其在珠江水系的空间分布

【背景】罗非鱼作为联合国粮农组织（FAO）向全世界推广养殖的优良品种之一,有多个品系,其养殖范围已遍布85个国家和地区。1956年我国从越南引进莫桑比克罗非鱼,经过养殖及推广,2006年我国罗非鱼产量达到100万t。但是,该外来物种在给我国带来良好经济价值的同时,对土著种类及水环境造成了极大的影响。【方法】对近几年珠江水系渔获物的调查数据进行整理,并观察尼罗罗非鱼早期发育形态,统计尼罗罗非鱼苗对其他鱼苗的最大捕食量及捕食规格,以分析罗非鱼生物学特性及其在珠江水系的入侵现状。【结果】尼罗罗非鱼早期发育快,卵黄营养非常丰富,比珠江水系土著种类更有竞争性;罗非鱼苗呈现很强的攻击性与捕食性;尼罗罗非鱼已经扩散到珠江水系各主要河流,并在部分江段形成优势种群。【结论与意义】尼罗罗非鱼种群快速扩张,对土著种已构成严重威胁,有必要将其列为珠江水系高危入侵种。     

Control of invasive marine invertebrates: an experimental evaluation of the use of low salinity for managing pest corals (Tubastraea spp.)

This study investigated the use of low salinity as a killing agent for the invasive pest corals Tubastraea coccinea and Tubastraea tagusensis (Dendrophylliidae). Experiments investigated the efficacy of different salinities, the effect of colony size on susceptibility and the influence of length of exposure. Experimental treatments of colonies were carried out in aquaria. Colonies were then fixed onto experimental plates and monitored in the field periodically over a period of four weeks. The killing effectiveness of low salinity depended on the test salinity and the target species, but was independent of colony size. Low salinity was fast acting and prejudicial to survival: discoloration, necrosis, fragmenting and sloughing, exposure of the skeleton and cover by biofoulers occurred post treatment. For T. tagusensis, 50% mortality (LC₅₀) after three days occurred at eight practical salinity units (PSU); for T. coccinea the LC₅₀ was 2?PSU. Exposure to freshwater for 45–120?min resulted in 100% mortality for T. tagusensis, but only the 120?min period was 100% effective in killing T. coccinea. Freshwater is now routinely used for the post-border management of Tubastraea spp. This study also provides insights as to how freshwater may be used as a routine biosecurity management tool when applied pre-border to shipping vectors potentially transporting non-indigenous marine biofouling species.     

微卫星位点BEM06与BEM23鉴别烟粉虱B型与Q型的有效性

烟粉虱Bemisia tabaci (Gennadius) B型与Q型是烟粉虱复合种中入侵性较强、分布较广的2种生物型, 当前在许多地区混合发生。这2种生物型的快速鉴别对其种群动态调查及入侵生态学研究具有重要价值。为了验证微卫星位点BEM06与BEM23鉴别B型与Q型烟粉虱的有效性, 本研究分析了这2个微卫星位点的等位基因在国内外17个B型、4个Q型、3个非B/Q型烟粉虱种群的分布特点。结果表明: 这2个微卫星位点的联合使用可鉴别B型与Q型烟粉虱, 但是无法有效地将B型、Q型与一些非B/Q型烟粉虱某些个体区分开来。结果提示: 利用微卫星位点BEM06与BEM23鉴别B型与Q型烟粉虱具有一定的局限性, 尤其是田间烟粉虱存在其他生物型时需要慎重使用这种鉴别方法。     

生物入侵的危害及防治措施

阐述了什么是生物入侵、入侵途径、入侵危害、影响入侵的因素和防治措施,提出对生物入侵要引起高度的重视和警觉井严加防范,尽快建立生物入侵的风险评价制度和预警机制。     

外来生物入侵防控体系建设研究

近年来随着我国经济的持续快速发展和进出口贸易量的增加,外来物种的引入和入侵的风险持续升高,外来入侵生物已对我国的自然生态系统、经济和社会发展造成了严重危害。如何建立一套完善的外来入侵生物防控体系是摆在相关从业者面前的一个重大研究命题。本研究系统梳理和分析了近年来国内外外来生物入侵现状以及防控措施,讨论了外来生物入侵防控体系功能特点,建议应从如下方面着手建设外来入侵生物防控体系:建立外来入侵生物防控工作协调机制,完善相关法律法规,及时建立、完善外来入侵生物数据库,建立外来入侵生物安全性风险评估和预警体系,加强海关检验检疫体系建设以及科学研究体系建设,借助大数据开展智能监测与绿色防控,并大力开展大众自然教育,提高全民对外来生物入侵危害的认识和防范意识,群策群防,提高防控和治理效率。通过以上建议以期能为我国生物入侵及其相关行业的发展和管理提供参考依据,早日建立并完善以政府为主导的一套外来生物入侵防控体系,将外来入侵生物带来的危害降到最低。     

Efficacy of physical removal of a marine pest: the introduced kelp <Emphasis Type="Italic">Undaria pinnatifida</Emphasis> in a Tasmanian Marine Reserve

The tools available for incursion response in the marine environment are limited, both in number and in situations where they can be appropriately applied. The ability to make decisions as to when and where a response should occur is limited by knowledge of the efficacy and costs. We undertook an evaluation of manual removal of Undaria pinnatifida sporophytes in a new incursion in the Tinderbox Marine Reserve in Tasmania over a 2.5 year study period. Plants were removed, from a 800 m² area, on a monthly basis to minimise the likelihood of maturation of sporophytes and subsequent release of zoospores. While manual removal appears to have significantly reduced the number of developing sporophytes, the persistence of hot spots through time suggests that either microscopic stages (zoospores, gametophytes or sporelings) create a seed bank that persists for longer than 2.5years or selective gametophyte survival in microhabitats occurs. In order for manual removal of Undaria to be effective a long-term commitment to a removal activity needs to be coupled with vector management and education initiatives to reduce the chances of re-inoculation and spread, with monitoring (and response) on a larger spatial scale for the early detection of other incursion sites, and with a treatment to remove persistent microscopic stages.     

Comparison of traditional and molecular analytical methods for detecting biological agents in raw and drinking water following ultrafiltration

Aims:  To compare the performance of traditional methods to quantitative polymerase chain reaction (qPCR) for detecting five biological agents in large-volume drinking-water samples concentrated by ultrafiltration (UF).
Methods and Results:  Drinking-water samples (100 l) were seeded with Bacillus anthracis , Cryptospordium parvum , Francisella tularensis , Salmonella Typhi , and Vibrio cholerae and concentrated by UF. Recoveries by traditional methods were variable between samples and between some replicates; recoveries were not determined by qPCR. Francisella tularensis and V. cholerae were detected in all 14 samples after UF, B. anthracis was detected in 13, and C. parvum was detected in 9 out of 14 samples. Numbers found by qPCR after UF were significantly or nearly related to those found by traditional methods for all organisms except for C. parvum . A qPCR assay for S. Typhi was not available.
Conclusions:  qPCR can be used to rapidly detect biological agents after UF as well as traditional methods, but additional work is needed to improve qPCR assays for several biological agents, determine recoveries by qPCR, and expand the study to other areas.
Significance and Impact of the Study:  To our knowledge, this is the first study to compare the use of traditional and qPCR methods to detect biological agents in large-volume drinking-water samples.     

Simulating control strategies for a spatially structured weed invasion: <Emphasis Type="Italic">Spartina alterniflora</Emphasis> (Loisel) in Pacific Coast estuaries

Patterns in the spatial arrangement of invasive plant populations can provide opportunity for strategic placement of control efforts. Smooth cordgrass (Spartina alterniflora) is rapidly invading the intertidal mudflats of Pacific Coast estuaries. Its pattern of spread is distinctive. Seedlings establish in open mud and then grow vegetatively to form expanding circular patches, which dot the mudflats and eventually coalesce into a contiguous monospecific meadow. The invasion typically begins in the upper tide zone and then moves down the tidal gradient. A spatially explicit model was used to simulate the spread of S. alterniflora and compare various strategies for control in a situation where only a fraction of the total infestation could be controlled each year. A strategy of killing outlying patches first and then attacking the dense meadows (moving up the tidal gradient) led to eradication with up to 44% less time and effort than a strategy of attacking the dense meadows first and outlying patches second (moving down the tidal gradient). In the control of contiguous meadows located adjacent to the shoreline, the best strategy was to approach one end of the infestation, moving across the meadow to the other end. Suppression of seeds was not an effective control strategy. In general, effective control strategies were those that first eliminate the plant in areas where current or future vegetative growth is greatest. Application of these results in control programs for S. alterniflora and similar invasive species could greatly reduce the costs of control work and improve the likelihood of local or complete eradication.     

Non-Indigenous Woody Invasive Plants in a Rural New England Town

We investigated the abundance of non-indigenous woody invasive plants in Farmington, Maine, a rural New England town in a forested landscape. We found 12 invasive species and more than 7 patches per km from surveys on 33 transects (54.3 km) along field edges, abandoned railroad right-of-ways, roadsides, and riparian zones. Invasive abundance was apparently lower than for more developed areas of the northeastern US, where, in contrast to western Maine, invasives have extensively penetrated forest interiors. Invasive abundance increased with the amount of landscaping and proximity to town, suggesting a close association between local horticulture and the spread of woody invasives. Invasive abundance and diversity were highest in riparian areas, probably due to relatively high levels of propagule pressure. Species differed in the extent of invasiveness, ranging from those still dependent on planted parent trees to fully invasive populations. The invasive species recorded in this study have caused environmental and economic damage elsewhere. The lower levels of invasiveness in Farmington are likely a result of the isolation, small human population, and forested landscape rather than low levels of invasibility. This suggests the potential for future risks, and the importance of intervention while populations can still be eradicated or controlled.     

Updated Models for the Effects of Temperature,Initial pH,NaCl, and NaNO2 on the Aerobic and Anaerobic Growth of Listeria monocytogenes

Data from several studies were appended to aerobic and anaerobic data sets that had been previously used to develop response surface models describing the growth kinetics of Listeria monocytogenes (Buchanan and Phillips, 1990). The expanded data sets included 709 aerobic and 358 anaerobic growth curves fitted with the Gompertz equation, and representing 189 and 150 unique combinations of four variables (temperature, pH, NaCl, NaNO₂), respectively. Response surface models were developed for (1) the Gompertz B and M terms and (2) lag phase durations (LPD) and generation times (GT). In addition to modeling NaCl as a variable, a second set of response surface models was developed by substituting calculated water activity as a variable. A number of data transformations were evaluated in an attempt to better utilize no-growth data. Full quadratic models of the natural logarithm transformation of the data (no-growth data excluded) predicted values that fit the observed data well. The assignment of GT=50[emsp4 ]h and LPD=600[emsp4 ]h (the approximate maximum duration of experiments) for the variable combinations that did not support growth proved to be the most effective means of making use of the no-growth data. However, this approach did not offer any clear advantage over quadratic models where the no-growth data were excluded. Error matrices were developed for the LPD and GT models to provide 95 % confidence intervals. The agreement between observed and predicted growth kinetics was excellent considering the number and ranges of the variables encompassed in the models. The models provide reasonable predictions of the growth of L. monocytogenes in foods. The full quadratic models of LPD and GT without inclusion of the no-growth data were selected for inclusion in the USDA Pathogen Modeling Program, release 5.1.     

扶桑绵粉蚧与长角立毛蚁的互惠关系及其对寄主棉花叶片叶绿素荧光特性的影响

【背景】草食动物对寄主植物的取食或损伤会诱导改变植物的光合作用,从而直接影响植株的健康生长。产蜜昆虫与蚂蚁的互惠关系是物种相互促进的一种重要的生态学现象,能够促进产蜜昆虫的种群数量,然而这种互惠关系及其对寄主植物光合生理的影响还知之甚少。【方法】在室内条件下,运用叶绿素荧光动力学技术研究了外来入侵害虫扶桑绵粉蚧与长角立毛蚁的互惠对寄主棉花叶片叶绿素荧光特性的影响。【结果】随着扶桑绵粉蚧危害时间的延续,寄主植物上蚂蚁和扶桑绵粉蚧的数量均呈现显著上升的趋势,而在危害后期,蚂蚁存在情况下扶桑绵粉蚧的数量要明显低于无蚂蚁处理;在扶桑绵粉蚧取食寄主棉花20 d后,有、无蚂蚁存在的棉花叶片的光合利用率α值较无虫处理分别下降了53.5%和37.0%;存在蚂蚁或扶桑绵粉蚧危害后期对棉花叶片最大相对电子传递效率r ETRmax有显著影响,然而扶桑绵粉蚧单独取食或与蚂蚁互作的情况下未显著影响棉花叶片对强光的耐受能力(Ek)。【结论与意义】研究明确了扶桑绵粉蚧与长角立毛蚁的互惠关系对寄主棉花叶片的光合生理产生了一定的负面效应,为进一步解释扶桑绵粉蚧入侵、扩散及暴发的生态学过程提供了科学依据。