The relative exploitation of annuals as larval host plants by European butterflies

Theoretically, Lepidoptera should be able to adapt to using annuals as larval host plants through increased development rates and migration capacity. Even so, we show that annuals are used less frequently as host plants than expected among British and continental European butterflies. In particular, no example has been found of a European butterfly monophagous on an annual plant over its entire range. Use of annuals is proportionately greater among species that exploit increasing numbers of host plants and among subsidiary host plants than among primary (main) host plants. Annuals as host plants change status as habitat components with changes in species' spatial dynamics. The statistical findings point to perennials as providing host plant refuges, whereas the few case examples of site monophagy suggest that annuals can become valuable complementary resources during range extensions such as those currently associated with climatic warming. Annuals are more likely to be used in highly restricted circumstances, when environmental conditions allow the plants to persist over prolonged periods (i.e. when they are behaving like biennials) or when their spatial predictability is high because of low seed dispersal.     

基于最小费用模型的辽河三角洲水禽生境绿道构建

生境破碎化会造成种群面临局地灭绝风险,而生境绿道的构建有利于增强生境之间的连接.以绿翅鸭为研究对象,采用最小费用模型构建的分析方法,解析了生境绿道构建的思路,形成了辽河三角洲水禽生境绿道构建的方案,分析了辽河三角洲生境绿道现状存在的问题,提出了相应的生态解决措施.     

不同生境拟穴青蟹螯足肌肉营养品质评价

为探究不同生境、不同食物源拟穴青蟹(Scylla paramamosain，以下简称“青蟹”)的螯足肌肉营养品质的差异，本研究通过采集5种不同生境青蟹(生态青蟹、藤壶青蟹、天然青蟹、混饵养殖青蟹和单饵养殖青蟹)，取其螯足肌肉组织测定基本营养成分、氨基酸含量和脂肪酸含量，并通过必需氨基酸指数(EAAI)、支链氨基酸与芳香族氨基酸含量的比值(F)进行分析。结果表明，生态青蟹的蛋白质含量略高于天然青蟹和混饵养殖青蟹；藤壶青蟹的含水率最高，蛋白质含量最低；5种青蟹的粗脂肪和总灰分含量差异均不显著。生态青蟹的总氨基酸含量和必需氨基酸含量均最高，藤壶青蟹的鲜味氨基酸含量最高；藤壶青蟹的EAAI (112.48)和F (2.36)最高，生态青蟹的EAAI (95.35)和F (1.95)分别与天然青蟹的EAAI (96.15)和F (1.90)基本一致；单饵养殖青蟹的EAAI (72.00)和F (1.53)均最低。生态青蟹的单不饱和脂肪酸、多不饱和脂肪酸含量最高，其二十二碳五烯酸+二十二碳六烯酸(EPA+DHA)显著高于天然青蟹，且部分不饱和脂肪酸含量显著高于天然青蟹、混饵养殖青蟹和单饵养殖青蟹。从蛋白质、总氨基酸、必需氨基酸和不饱和脂肪酸的含量来看，生态青蟹的含量最高；从EAAI和F来看，藤壶青蟹的评价最高，说明2种红树林生态修复产出的青蟹品质较好。     

极权场域中的极权主义者——论《一九八四》中的主人公温斯顿

运用法国社会学家皮埃尔.布迪厄（Pierre Bourdieu）的场域理论来对小说《一九八四》中的主人公温斯顿进行分析研究。认为温斯顿虽然是极权主义的一个受害者,但他所做出的种种＂反惯习＂的行为却恰恰符合了极权社会统治者的＂真惯习＂,温斯顿本质上是一个地地道道的极权主义追随者。     

Anuran assemblage composition and distribution at a modified environment in Três Marias reservoir,south-eastern Brazil

We assessed the influence of environmental features on anuran species distribution in Pirapitinga, an island formed by the filling of a reservoir in south-eastern Brazil. We investigated whether the species exhibited preferences towards certain habitat types and the existence of niche partitioning. We recorded 474 individuals from seven species. Although considered as generalists, these species were not distributed randomly, but according to specific habitat preferences that happened to be fulfilled by the shores of the reservoir. Niche overlaps were higher than expected by chance during the wet season, when most species were active, but not different from random during the dry season. Environmental variables seemed to be important and promote aggregation of several anuran species at the same habitats. Interspecific signals may be used for this purpose, and competition is probably small or less important than the benefits provided by choosing the most suitable habitats in this impacted environment.     

Oribatid mite (Acari) community structure in steppic habitats of Burgos Province,central northern Spain

This work is a study of the communities of oribatid mites in steppic areas of Burgos Province, central northern Spain, in relation to different habitat types belonging to natural or disturbed ecosystems. The primary objective was to find the relationship between anthropogenic use of land and several diversity indices. Parameters such as abundance, species richness, real diversity (H′) and equitability (J′) of the mite communities were calculated in 20 soil plots, sampled in spring and autumn 2000, belonging to the predominant habitat types of this area: (1) cultivated lands, (2) abandoned crop lands, (3) grasslands/pastures, and (4) natural oak forests or a pine plantation. The most widespread species in the area as well as the most abundant taxa overall are documented, together with the faunistic checklist of oribatid mites identified in the study. The results show a general decline in the composition of the oribatid community, in terms of species diversity and abundance, from non‐disturbed soils to cultivated lands. The number of species (richness) was usually higher in forest soils than in disturbed ecosystems, in which the most degraded soils showed the lowest number of species. The community analysis shows the differences due to habitat type and ubiquitous bioindicator species.     

厦门鹭类集群营巢地分布及其生境特性的研究

2003年厦门境内分布有10个鹭类集群营巢地,营巢地鹭类平均数量1 918±567只.其中,白鹭、夜鹭、池鹭和牛背鹭繁殖群的平均数量分别为1 721±518,99±25,87±31和11±9.9只.营巢地的鹭类营巢密度平均为0.98±0.14(巢/m2).鹭类营巢地形成的最早时间为2月,最迟为5月.厦门的鹭类营巢地数量存在着变化,近5年共丧失6个鹭类营巢地,其中,营巢地林区发生火灾和工程建设土地需要各占50%的诱因.关键因子分析结果表明,营巢地受保护程度、营巢地植被、人为干扰程度以及营巢地与湿地的距离是影响鹭类集群营巢地分布的主要环境因素.因此,在鹭类营巢地管理工作中,应当重点保护营巢地的上述环境特征,同时重视防火工作.     

蛇岛蝮蛇的选择与适应

蛇岛蝮蛇 (GloydiusshedaoensisZhao)之所以在一个孤岛上繁衍生息上万年间 ,首先是蝮属蛇类都具有捕食鸟类的精良武器———毒牙与颊窝 ,捕食时能选择有利地形并采取拟态伪装和“守株待鸟”的对策 ,当食物淡季来到时便以“夏眠”的方式渡过炎热的夏季 ,以减少能量消耗 .蛇岛蝮蛇的食物很有限 ,捕食季节也很短 ,可它的能量转化率很高 ,并能将剩余的能量以脂肪的形式储存在体内 .它们还有很强的耐饥力和耐渴力 ,即使错过了一个捕食期 ,只要在下一个捕食季节获得一定的食物就足够了 .在种群生殖上它们选择了降低生殖数量、提高生殖质量的策略 ,刚出生的小蛇就能捕食小鸟 ,使之长期保持一个健康的种群 ,这就是自然选择与适应的结果     

生态位构建通过修复破坏生境对集合种群动态的影响

基于具有生境破碎作用下的集合种群模型，建立了存均匀场假设下的微分方程模型，充分探讨了具有生态位构建效应的有机体活动对破碎斑块修复产生的生态结果．通过稳定性分析与元胞自动机方法模拟表明：集合种群的续存条件不仪依赖于侵占力与灭绝率之间的平衡，而且也包括集合种群的生态位构建能力与生境自然消耗率之间的平衡；当灭绝率大于侵占率时，集合种群也可以在低水平上续存，并且在该过程中集合种群依赖于两个阈值条件，分别是生态位构建能力和集合种群的初始状态．集合种群的大小与其生态位构建能力成正比，即构建能力强者，集合种群数量相应增加．因此，对环境具有较强的正效应的有机体或种群在维护牛境的有效性中起重要作用．     

野生扬子鳄栖息地土壤金属元素含量初步研究

2002年9—11月，作者在皖南地区对扬子鳄栖息地进行了质量评估，主要是对现有野生鳄的栖息地以及曾经有鳄分布的栖息地共20样点土壤中的Cd、Pb、Zn、Cu、Fe、Ca、Mg等7种金属元素含量进行测定，对重金属元素的数据分析，采用我国土壤元素背景值作为评价标准，每个样点的污染程度以多因子评价指数为指标，发现曾经有鳄分布的样地土壤中的重金属元素含量较其它样地的重金属元素含量高，野生扬子鳄对于栖息地的无机环境是有一定的依赖性的，人类的生产、生活不但影响了野生扬子鳄的生物环境，也影响和改变了野生扬子鳄的无机环境。