Lignoid chemical defenses in the freshwater macrophyte Saururus cernuus

Summary. Chemical defense against herbivores has rarely been investigated for freshwater plants, possibly due to the common misconception that herbivory on aquatic macrophytes is low and would not select for chemical defenses. In previous work, the freshwater angiosperm Saururus cernuus was shown to be a low preference food for omnivorous crayfish despite its high nutrient value and relatively soft texture. We used feeding by the crayfish Procambarus clarkii to guide fractionation of the deterrent lipid-soluble extract of this plant, leading to the identification of seven deterrent lignoid metabolites, (–)-licarin A, (+)-saucernetin, (–)-dihydroguaiaretic acid, (–)-sauriols A and B, (–)-saucerneol, and (–)-saucerneol methyl ether. Lignans have been implicated in terrestrial plant chemical defenses as insect growth inhibitors, insect toxins, nematocides, antibacterial, and antifungal agents. However, these activities have rarely been demonstrated using ecologically relevant methodologies in terrestrial systems, and never before in freshwater systems. The widespread nature of lignans amongst very distantly related plants, along with their rich diversity of molecular structure, suggests that they could play a large role in mediating plant-herbivore interactions. In addition to the lignoid compounds we identified, there were other compounds present in low concentration or unstable compounds that were deterrent, that did not appear to be lignans, but that we were unable to identify. This plant thus appears to be defended by a complex mixture of natural products. Received 6 June 2000; revised 23 August 2000; accepted 2 September 2000     

Biotransformation of 4-nerolidylcatechol by Heraclides brasiliensis (Lepidoptera: Papilionidae) reduces the toxicity of Piper umbellata (Piperaceae)

Heraclides brasiliensis (Lepidoptera: Papilionidae) larvae feed preferably on Piperaceae, foraging successfully on leaf tissues even though species of this contain high levels of secondary metabolites such as amides and lignans, associated with diverse biological activities including insecticidal properties. Studies examining the metabolism of chemical constituents in Piperaceae by insects are rare. In this study, we characterized the metabolites of 4-nerolidylcatechol (4-NC), the major constituent of Piper umbellata (Piperaceae), and E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, compounds from fecal material of H. brasiliensis larvae fed a diet containing only P. umbellata leaves. The biotransformed product was also detected in larval and pupal tissues. Moreover, we observed deactivation of the toxicity of P. umbellata leaves against brine shrimp after their metabolism in H. brasiliensis larvae from a LC₅₀ of 523.3 to 3,460.7 μg/mL. This deactivation is closely associated with the biotransformation of 4-NC to E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, which showed LC₅₀ of 8.0 and >1,000 μg/mL, respectively.     

Higher education in urban environmental management: a new programme at the Asian Institute of Technology,Bangkok

Environmental management and planning is now considered as a new field of professional expertise. There are even professional associations for interested professionals. To date, urban environmental management has been regarded as a subdiscipline of environmental management, but since the Rio Conference in 1992, with the new focus of urban management on environmental problems, it can itself be considered as a professional field. This paper traces the emergence of the field and tries to identify the new skills required for it. The question of formal training, in higher education, for a new type of professional is raised and discussed. It refers at length to an initiative taken by the Asian Institute of Technology (Bangkok) to propose and offer a new graduate programme in this discipline, and draws on the author's experience of an Asian workshop (Bangkok, May 1993) aimed at defining the need for such a new profession in Asia.     

New birds on the block: new neighbors increase defensive costs for territorial male willow ptarmigan

Previous researchers have hypothesized that site-faithful animals may benefit from the presence of familiar neighbors. This study compares the relative costs of territorial defense against new and former neighbors by male willow ptarmigan (Lagopus lagopus). Territorial defense against new neighbors appeared to require a greater expenditure of both time and effort than did defense against former neighbors. Territorial males that had several new neighbors spent a higher proportion of time fighting than did males with fewer new neighbors, and males with both new and former neighbors spent a greater amount of time fighting with their new neighbors, on average, than with their former neighbors. In addition, fights with new neighbors occurred relatively more frequently and were longer than fights with former neighbors. Finally, fights involving new neighbors tended to escalate to higher levels than fights between former neighbors. Reduced defensive costs for site-faithful, territorial males may provide one explanation for the tendency of males to be more site-faithful than females in many species.     

Development of new dunes in the Dutch Delta: nature compensation and ‘building with nature’

A new dune area was constructed by beach and foreshore nourishments along the Delfland Coast in the southwestern Netherlands. The new area is intended to be a compensation for losses of existing high quality dunes in nearby areas, due to the use/construction of Maasvlakte 2, the new harbour extension of Rotterdam opening in 2013. The target habitats for compensation include dry grey dunes and moist dune valley grassland. Due to the habitat type, the nourished material had to have a special character. The nourishment was carried out according to a special design and initial development of the new area had to follow certain pathways. In order to meet the compensation requirements in time. Careful monitoring is done to assess whether development of the new habitat is taking place in the direction of the desired target habitats. This paper reports on the construction of the new area and on the first years of development and monitoring. The monitoring mainly concerns development of the abiotic landscape elements, geomorphology, groundwater and soils. The lessons learned from this area are discussed in the light of the development of other recent young nature areas in the sandy Dutch delta coast. This gives new insights for coastal management in general in the context of building with nature.     

Predaceous gastropods regulate new-shell supply to salt marsh hermit crabs

Marsh hermit crabsPagurus longicarpus Say directly acquire new shells as the predatory gastropodMelongena corona Gmelin consumes marsh periwinkles,Littorina irrorata Say. The influx rate of new shells into a salt marsh hermit crab population was measured by marking live periwinkles and daily recovering the shells from hermit crabs over periods of 3 to 6 d. Average rates of new shell acquisition ranged from 4.0 to 23.3 new shells per day from salt marsh areas of 4×10 m. Such consistently high rates contrast with the negligible rates generally assumed for new shell entry into hermit crab populations. The number of new shells acquired each day varied directly with the number of the predatory gastropod,M. corona, present in each study area at both natural and manipulated predator densities. Empty shells on the substrate are usually considered as the primary source of new shells to hermit crabs. However, over 500 empty shells had to be placed on the substrate in a 4×10 m area to provide a daily rate of 20 new shells to the hermit crab population.This is the first in a new contribution series from the Florida State University Marine Laboratory No. 1001     

Territorial fidelity of willow warbler (Phylloscopus trochilus) males and success in competition over territories

Summary Territorial fidelity and competition between males was studied in a population of individually marked willow warblers (Phylloscopus trochilus). After spending the winter in Africa males arrive in the study area in late April or the beginning of May. They can be separated into two categories, old colour-banded males that return for a new breeding attempt, and birds that are new to the study area. These new birds could either be birds that had bred the previous year returning to a different site, or more likely 1-year-old birds returning for their first breeding attempt. Old males show high site fidelity and are successful in retaining their territories from the preceding year. The few old males that switched territories between years seemed to do so in response to reduced breeding success in the preceding year. However, in 13 out of 14 cases when a new resident was already established on the previous resident's territory, the old male was successful in evicting the new resident. In a removal experiment both old and new birds were removed from their territories and then released when a replacement male had been established. All old males successfully managed to reclaim their original territories after escalated contests. None of the new males were successful and no fights were observed.     

A model for measuring leaf growth rate of vegetative shoot in the seagrass, Zostera marina

A new model for determining leaf growth in vegetative shoots of the seagrass Zostera marina (eelgrass) is described. This model requires the weights of individual mature and immature whole leaves and leaf plastochrone interval (P_L) as parameters, differing from the conventional leaf marking technique (CLM) that requires cutting and separation between new and old tissue of leaves. The techniques required for the model are the same as for the plastochrone method, but the parameters differ between both methods in use of the weight of individual immature leaves. In a mesocosm study, eelgrass growth was examined, and parameters for the new model and plastochrone method (the weights of individual mature and immature leaves and P_L) were measured. Leaf growth rate was measured using the CLM and determined by the new method and the plastochrone method. The results were then compared between the CLM, the new model, and the plastochrone method. The results obtained with the new model were similar to those obtained with the CLM. However, the results of the plastochrone method differed from those of the CLM, while the weight of immature leaves varied seasonally. The new model was also used to determine leaf growth in a natural eelgrass bed in Mikawa Bay, Japan, and revealed the growth rates in all shoots and those of different ages. This method would be advantageous as an accurate means of direct measurement in fieldwork, and should therefore be a useful tool for monitoring seagrass growth.     

OECD鱼类生物蓄积测试的优化策略研究

作为化学品风险管理中的重要环境行为参数,生物蓄积性不仅是分类、标签、评价和控制环境风险的基本指标,也是鉴别化学物质持久性和环境危害性的重要标准。2012年OECD颁布了新的生物蓄积测试方法,由此给生物蓄积优化策略带来了全新的挑战,原有的判别优化策略的方法需要作出新的发展与调整。针对新生物蓄积测试方法引发的优化策略挑战,通过层次研究及文献分析,归纳了基于OECD新305生物蓄积测试标准的优化测试策略,为优化、简化测试及化学品安全管理提供了科学基础。     

衡阳市企业执行新企业会计准则情况的调查与分析

目前,新会计准则在我国上市公司中实施已有六年多时间,然而在我们衡阳市企业中的运用情况如何,企业的反映如何,在实施过程中有哪些问题和难题,这些都是普遍关注的问题.因此,为进一步了解新会计准则的实施情况,发现并解决实施过程中存在的问题和难题,课题组对衡阳市相关企业的新会计准则实施情况进行了调查和分析.参8.     

中国土壤科学战略发展研究的新思路——土壤学战略发展研究的顶层设计与路线图

土壤科学在国家农业可持续发展和生态环境建设中具有重要的战略地位。文章论述了当前新形势下,土壤科学战略发展的新思路和新目标,从科学目标和国家需求方面阐述了未来土壤科学战略发展的新方向,构建了土壤科学战略发展的顶层设计图,提出了我国2020-2050年土壤科学战略发展总思路,并对此进行了综合提示与深入思考。     

Follicovitellosum indicum,a new trematode,found in the fish Belone belone

A new trematode, collected in 1971 from Ratnagiri, India, is described as Follicovitellosum indicum sp. nov. A new subfamily, Follicovitellotrematinae is created within the family Zoogonidae Odhner, 1911, to receive the new genus Follicovitellosum, with its genotype F. indicum. The new species is characterized by the follicularized nature of its ovary; the ovarian follicles are posttesticular. The vitellarium is further divided into several follicles which are largely in the pre-ovarian zone, but post-acetabular and posttesticular in location.     

天津滨海新区湿地环境演化与景观格局动态

从历史演化和景观格局动态变化两个方面对天津滨海新区湿地生态系统的演变进行了研究。历史上天津地区为海洋,自滨海新区成陆以来,经历了多次的海浸和洪水淹没,海浸期间发生陆地湿地化,海退和洪水退却时发生水体湿地化。本文总结了自地质时期以来的历史演化模型。同时在GIS和RS技术支持下,运用FRAG-STATS软件,研究了1979-2008年滨海新区湿地景观格局动态变化特征。结果表明,随着滨海新区的发展和土地利用强度的增大,研究区景观斑块数量增加、平均斑块面积减少的趋势比较明显,景观呈现破碎化的趋势;总体上,近30年中,滨海新区湿地总面积变化不大,并没有大面积持续减少。景观破碎程度从1979年开始持续上升,中间略有波动,但总体上升较快。     

基于净初级生产力的生态足迹模型及其与传统模型的对比分析

生态足迹模型因其可以定量度量生态可持续发展、计算简单、结论易懂、全球可比等特点,提出之后得到了大量的关注和应用,同时也面临着一些质疑和争论。文章介绍了一种基于净初级生产力的生态足迹理论和计算方法,并以该方法和传统生态足迹模型分别计算了中国1961—2007年的生态足迹,对计算结果进行了对比分析。结果表明,两种生态足迹模型的计算结果具有较高的相关性,表明基于净初级生产力的生态足迹模型结果可信。该种方法能够克服传统生态足迹模型的部分缺陷,在均衡因子选取、土地生态功能假设、CO2吸收等方面有了较大改进,能够较好地反映不同生态系统在生产力上的差异;在时间序列分析方面也更加合理。但该方法本身同时存在着计算方法不完善、对生态系统变化不敏感等问题,如何更紧密地结合生态足迹和净初级生产力是需要进一步研究的内容。     

中国崖爬藤属（TETRASTIGMA（MIQ．）PLANCH．）植物系统分类研究

崖爬藤属在中国物种分化特别多样。文中列出的国产种类是在对中国、印度支那半岛、印度半岛和喜马拉雅地区等植物种类的研究基础之上确定的。通过对上述不同地区存放在中国和法国巴黎自然历史博物馆（Ｐ）、英国邱园（Ｋ）及爱丁堡（Ｅ）皇家植物园等标本馆藏植物种类的比较研究，提出了本属植物的一个新分类系统，发表了国产的一些新分类群，也作了一些新组合。     

Understanding conservationists’ perspectives on the new‐conservation debate

A vibrant debate about the future direction of biodiversity conservation centers on the merits of the so‐called new conservation. Proponents of the new conservation advocate a series of positions on key conservation ideas, such as the importance of human‐dominated landscapes and conservation's engagement with capitalism. These have been fiercely contested in a debate dominated by a few high‐profile individuals, and so far there has been no empirical exploration of existing perspectives on these issues among a wider community of conservationists. We used Q methodology to examine empirically perspectives on the new conservation held by attendees at the 2015 International Congress for Conservation Biology (ICCB). Although we identified a consensus on several key issues, 3 distinct positions emerged: in favor of conservation to benefit people but opposed to links with capitalism and corporations, in favor of biocentric approaches but with less emphasis on wilderness protection than prominent opponents of new conservation, and in favor of the published new conservation perspective but with less emphasis on increasing human well‐being as a goal of conservation. Our results revealed differences between the debate on the new conservation in the literature and views held within a wider, but still limited, conservation community and demonstrated the existence of at least one viewpoint (in favor of conservation to benefit people but opposed to links with capitalism and corporations) that is almost absent from the published debate. We hope the fuller understanding we present of the variety of views that exist but have not yet been heard, will improve the quality and tone of debates on the subject.     

Mating by pregnant water voles (Arvicola terrestris): a strategy to counter infanticide by males?

Summary Pregnant water voles (Arvicola terrestris) shift nest location, with the result that some females may move into the home range of a new male. These females were found to have a vaginal plug while still pregnant, indicating a recent mating with the new male. No vaginal plugs were found in pregnant females that stayed within their original male's home range. No indications of pregnancy termination were observed in females that encountered a new male. This suggests that pregnant female water voles mate with the new male to prevent infanticide by confusing paternity.     

浅析我国青少年犯罪的原因及对策

进入新世纪后,我国青少年犯罪出现许多新情况,表现出许多新的特点,究其原因不外乎两个方面:一是客观原因,二是主观原因,因此为了减少和遏止青少年犯罪,必须采取对策进行有效的预防和治理.     

Fuel prices and new vehicle fuel economy—Comparing the United States and Western Europe

Several recent papers have documented an effect of fuel prices on new vehicle fuel economy in the United States. This paper estimates the effect of fuel prices on average new vehicle fuel economy for the eight largest European markets. The analysis spans the years 2002–2007 and uses detailed vehicle registration and specification data to control for policies, consumer preferences, and other potentially confounding factors. We find fuel prices to have a statistically significant effect on average new vehicle fuel economy in Europe. The effect estimated for Europe is much smaller than comparable estimates for the United States.