露天采矿形成的人工湖中的水鸟建群(英文)

1999-2003年,在捷克共和国特布盆地生物圈保护区(Tebo Basin Biosphere Reserve)内,我们对13个采矿后形成的人工湖中水鸟群落的形成过程进行了研究.我们假定生活在邻近鱼塘中的水鸟会逐渐向这些人工湖迁移和聚集.在这些人工湖中共记录到42种水鸟,隶属于10个目,其中17种典型的海滨鸟类是该群落的重要组成部分.这些水鸟的季节动态过程与各物种自身的生活史阶段有关(如筑巢、迁徙),同时也被人类的采矿活动所影响.环境因素和人类干扰影响了绿头鸭(Anas platyrhynchos)、疣鼻天鹅(Cygnus olor)和凤头鸊鷉(Podiceps cristatus) 等优势种的分布.沙坑湖作为一种独特的生境为本保护区的濒危物种提供了栖息地,如:小苇(开鸟)(Ixobrychus minutus)、大苇莺(Acrocephalus arundinaceus)及其它潜在分布的鸟类.对南波西米亚地区沙坑湖鸟类的研究,可为其它相似地区水鸟群落演替研究提供了重要经验     

Characterization of microsatellite loci from the Japanese eel Anguilla japonica

The Japenese eel, Anguilla japonica, is generally assumed to be composed of a single population with wide distribution range, and some genetic studies using allozyme or mitochondrial DNA methods supported this population model. However, one genetic study suggested the existence of multiple populations in this species, and thus, more detailed studies on the population structure is needed. Here we characterized a total of 11 microsatellite markers of the Japanese eel. These will serve as powerful tools for detailed population study for the Japanese eel, though two of them showed the significant departure from the Hardy–Weinberg expectations.     

The use of fish parasites as bioindicators of heavy metals in aquatic ecosystems: a review

Parasites are attracting increasing interest from parasite ecologists as potential indicators of environmental quality due to the variety of ways in which they respond to anthropogenic pollution. In environmental impact studies certain organisms provide valuable information about the chemical state of their environment not through their presence or absence but instead through their ability to concentrate environmental toxins within their tissues. Free living invertebrates, notably bivalve molluscs, are commonly employed in this role as `sentinel organisms' to monitor the concentrations of bioavailable metals in aquatic ecosystems. Also certain parasites, particularly intestinal acanthocephalans of fish, can accumulate heavy metals to concentrations orders of magnitude higher than those in the host tissues or the environment. The comparison of metal accumulation capacities between acanthocephalans and established free living sentinel organisms revealed significantly higher concentrations of several elements in Acanthocephalus lucii (Müller) than in the Zebra mussel Dreissena polymorpha (Pallas) which is a commonly used bioindicating organism in Europe. In contrast to the high heavy metal concentrations recorded in adult acanthocephalans, the larval stages in their respective crustacean intermediate hosts show little tendency to accumulate metals. A number of experimental studies demonstrate a clear time dependent accumulation of lead for acanthocephalans in their final hosts. These investigations provide evidence that the extremely high metal concentrations in intestinal acanthocephalans of fish are not the result of a slow process of accumulation but instead a relatively rapid uptake to a steady-state level. Thus, metal concentrations in adult acanthocephalans respond rapidly to changes in environmental exposure of their hosts. The value of parasites for environmental monitoring will be discussed in detail in the present article.     

The effects of shredding invertebrates on the transfer of organic carbon from littoral leaf litter to water-column bacteria

Leaf litter can be of great importance for the productivity of small oligotrophic lakes surrounded by deciduous forests. Feeding invertebrate shredders produce particulate organic leftovers, but their feeding also enhances the release of dissolved organic carbon (DOC). We tested whether invertebrate-mediated DOC release affects the production of heterotrophic water-column bacteria. Submersed leaves were incubated in microcosms with and without shredders; and DOC, absorbance, bacterial abundance and bacterial production in the water column were monitored. We also measured dry weight of the organic particles (FPOC, fine particulate organic carbon, leaf residues and shredders). Total leaf-litter carbon decreased by nearly 80% in the presence of shredders, and on average 56% of the initial leaf carbon ended up as FPOC after 126 days of incubation. Without shredders FPOC production was almost zero, and 72% of the added leaf carbon could be retrieved as leaves when the experiment ended. Both these figures include the rapid release of DOC during the first week of leaf incubation in the lake water (equivalent to 16–19% of total added leaf carbon). Although bacterial production in the water was several times higher in treatments with shredders, bacterial consumption of leaf-derived DOC from shredding was obviously of minor importance in the total carbon budget. This result suggests, although shredders have a strong impact on transformation of leaves to FPOC, they do not greatly enhance the initial rate of mineralization of the leaf-derived detritus.     

Some observations on the age and growth of thin-lipped grey mullet, Liza ramada Risso, 1826 (Pisces, Mugilidae) in three North African wetland lakes: Merja Zerga (Morocco), Garâat Ichkeul (Tunisia) and Edku Lake (Egypt)

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in three North African wetland lakes: Merja Zerga (Morocco), Garâat Ichkeul (Tunisia) and Edku Lake (Egypt). Age structure of the mullet populations was very similar in all three study lakes. Small differences in growth were indicated, especially for the Moroccan population, where growth tended to be slower than for the other two populations. The fastest growth was observed in the Edku population while the best condition was observed in the Ichkeul population. Compared with some European populations, the sampled North African populations have faster growth and better condition factors.     

The Wilderness Act and Fish Stocking: An Overview of Legislation, Judicial Interpretation, and Agency Implementation

Many high-elevation lakes in designated wilderness are stocked with native and nonnative fish by state fish and game agencies to provide recreational fishing opportunities. In several areas, this practice has become controversial with state wildlife managers who support historical recreational use of wilderness, federal wilderness managers who assert that stocking compromises some of the ecological and social values of wilderness, and different public groups that support one or the other position. Herein we examine this controversy from the perspective of the 1964 Wilderness Act, its judicial interpretation, the policies of the federal agencies, and formal agreements between federal and state agencies. Although some state stocking programs restore native fish populations, other programs may compromise some of the ecological and social values of wilderness areas. Further, although current federal regulations recognize state authority for fish stocking, judicial interpretation gives federal agencies the authority for direct involvement in decisions regarding fish stocking in wilderness. Where there are differences of opinion between state and federal managers, this judicial interpretation strongly points to the need for improved cooperation, communication, and coordination between state wildlife managers and federal wilderness managers to balance recreational fishing opportunities and other wildlife management activities with wilderness values. Received 28 March 2000; Accepted 16 August 2000.     

长江三峡库区及其邻近地区的残存稀有濒危植物群落

长江三峡库区及其邻近地区的残存稀有濒危植物群落属于中亚热带绿落叶阔叶混交林。群落所处自然环境少生境独特;群落中有数种至十余种稀有濒危植物群聚生长,且以其中的部分稀有濒危植物为优势种。独特的生增昨良好的群落结构被认为是该类群落得以保存的主要原因,应加强对该类群落的就地保护研究。     

生态群落物种共存的进化机制

本文概述了目前对生态群落的物种共存研究中存在的若干问题及动、植物群落物种共存机制的研究进展。植物群落的物种共存主要介绍与环境、种子再迁移、生态位分化、竞争平衡理论、种库假设、再生生态位等有关的几种假设、生态学上相似种的共存及“原”群落概念等。动物群落的物种共存机制主要从以下几方面叙述：（1）异质环境中的资源分割,主要指动物斑状滋养的不同利用;（2）避免竞争排斥的行为机制,如边缘效应、聚群效应、扩散行为、相互作用和干扰;（3）特化者和泛化者的共存,包括：竞争是物种向多功能进化的作用力、最佳觅食理论与生态学特化及特化概念的发展。最后指出进一步研究的方向。     

真菌发酵生产鱼油特征脂肪酸

DHA和EPA是鱼油的特征脂肪酸,具有调整血脂、改善大脑功能和维持正常视力等重要作用.一直以来,其来源主要是海产鱼油.近年研究发现许多微生物的脂质中也含有DHA和EPA,特别是一些低等真菌含量甚为丰富,利用其发酵生产DHA和EPA替代鱼油资源具有广阔的前景.阐述了能产生EPA,DHA的真菌及其合成途径和发酵影响因素.