关键词： 动物园   事业   实践活动   解放思想  

摘要： 根据石园党字[2008]10号文《关于围绕三年大变样开展双创双树主题实践活动的实施意见》,结合我园边建设,边开放的实际,紧紧围绕突出创新,突出实践,突出标准,突出解决实际问题这四

关键词： 动物   肝炎病毒   模型   树胸  

摘要： 肝炎的的大范围流行已成为国内外关注的重要公共卫生问题之一。甲肝、乙肝虽已有疫苗,但不能忽视未来由于病毒变异所带来的威胁。丙肝目前尚未发现非常有效的疫苗,且丙肝的病理学机制也尚未完全清晰,主要原因是缺乏理想的动物模型。树胸属于低等灵长类动物。研究发现,他对很多人类疾病易感,所以建立肝炎树胸动物模型成为现在肝炎研究的一个热点。本文介绍了各型肝炎主要是甲、乙、丙型肝炎研究中建立树胸动物模型的自内外进展情况及存在的问题。

关键词： 株树桥水库   浮游动物   群落生态   水质评价   环境保护  

摘要： 对株树桥水库进行为期一周年的浮游动物群落结构特征研究,以期利用浮游动物群落结构变化,并结合理化指标对株树桥水库进行水质综合评价,进而为水库的合理、有效地利用提供基础资料。2007年5月至2001年4月,在水库的主要干道设置10个采样点,对浮游动物进行定性和定量的采集,同步进行温度、PH值和电导率三项物理指标以及氨氮、总磷、总氮、COD和溶解氧五项化学指标的测定。　　 通过浮游动物的种类鉴定,确定了常见种和优势种,同时分析研究了浮游动物群落变化以及温度、pH值、溶解氧和氨氮对浮游动物群落的影响。主要结果如下:　　 株树桥水库共鉴定出浮游动物184种。其中原生动物95种,轮虫71种,枝角类10种,桡足类8种。夏季和秋季的种类数较多,分别达120和138种;春季和冬季次之,种类数分别为72种和64种;而全年均出现的种类有36种。　　 株树桥水库10个采样点的浮游动物数量和生物量的年际变化趋势基本一致,全年浮游动物数量的变动幅度为712-4190ind./L,生物量变动幅度为0.347-2.783mg/L。　　 在水平分布上,上游入口的年均数量最多,生物量最多在升平口,数量和生物量大坝1均最少;在季节分布上,株树桥水库浮游动物数量和生物量在不同季节波动较大,数量表现为秋季>夏季>春季>冬季。生物量表现为夏季>秋季>春季>冬季。　　 浮游动物多样性指数、丰富度指数、均匀度指数大致都是9月,11月较高,1月份最低,优势集中性指数则相反。　　 浮游动物种类数有随着温度的升高而增加的趋势;种类数的年际变化与水体PH的变化关系不明显;浮游动物数量在夏、秋季节与溶解氧含量有显著的相关性;氨氮量高的冬春季,浮游动物种类较少,氨氮量低的夏秋季,浮游动物种类反而较高。　　 通过理化指标的测定,采用化学评价指数(Pb/n)和评分法对内河水质进行评价。同时利用浮游生物现存量、指示生物法、三种多样性指数即Simpson多样性指数、Shannon-Wearer多样性指数和Margalef多样性指数,分别对水库进行水质生物学评价。最后,结合理化指标,对水库进行了营养型评价。　　 综合各种评价方法,测定水库的水质大多处于寡污至乙型中污之间,营养型主要为中营养型。最后结合目前水库水质状况,提出合理开发利用的意见和建议。

关键词： 株树桥水库   浮游动物   群落生态   水质评价   环境保护  

摘要： 对株树桥水库进行为期一周年的浮游动物群落结构特征研究,以期利用浮游动物群落结构变化,并结合理化指标对株树桥水库进行水质综合评价,进而为水库的合理、有效地利用提供基础资料。2007年5月至2001年4月,在水库的主要干道设置10个采样点,对浮游动物进行定性和定量的采集,同步进行温度、PH值和电导率三项物理指标以及氨氮、总磷、总氮、COD和溶解氧五项化学指标的测定。 通过浮游动物的种类鉴定,确定了常见种和优势种,同时分析研究了浮游动物群落变化以及温度、pH值、溶解氧和氨氮对浮游动物群落的影响。主要结果如下： 株树桥水库共鉴定出浮游动物184种。其中原生动物95种,轮虫71种,枝角类10种,桡足类8种。夏季和秋季的种类数较多,分别达120和138种;春季和冬季次之,种类数分别为72种和64种;而全年均出现的种类有36种。 株树桥水库10个采样点的浮游动物数量和生物量的年际变化趋势基本一致,全年浮游动物数量的变动幅度为712-4190ind./L,生物量变动幅度为0.347-2.783mg/L。 在水平分布上,上游入口的年均数量最多,生物量最多在升平口,数量和生物量大坝1均最少;在季节分布上‘,株树桥水库浮游动物数量和生物量在不同季节波动较大,数量表现为秋季>夏季>春季>冬季。生物量表现为夏季>秋季>春季>冬季。 浮游动物多样性指数、,丰富度指数、均匀度指数大致都是9月,11月较高,1月份最低,优势集中性指数则相反。 浮游动物种类数有随着温度的升高而增加的趋势;种类数的年际变化与水体PH的变化关系不明显;浮游动物数量在夏、秋季节与溶解氧含量有显著的相关性;氨氮量高的冬春季,浮游动物种类较少,氨氮量低的夏秋季,浮游动物种类反而较高。 通过理化指标的测定,采用化学评价指数(Pb/n)和评分法对内河水质进行评价。同时利用浮游生物现存量、指示生物法、三种多样性指数即Simpson多样性指数、Shannon-Wearer多样性指数和Margalef多样性指数,分别对水库进行水质生物学评价。最后,结合理化指标,对水库进行了营养型评价。 综合各种评价方法,测定水库的水质大多处于寡污至乙型中污之间,营养型主要为中营养型。最后结合目前水库水质状况,提出合理开发利用的意见和建议。

关键词： Saplings   Herbivores   Regrowth   Browsing   Savannas   Applied ecology   Ungulates   Animal social behavior   Forest ecology  

摘要： Suppressed growth forms of woody species are common where fire and herbivory are major ecosystem drivers, such as in African savannas. Nevertheless, despite their importance in maintaining plant population viability, woody plants in suppressed growth forms have received little attention in ecological studies. We measured a set of morpho-functional traits and investigated plant density variation in suppressed growth forms (hereafter we refer to them as saplings) of two common species, Acacia nigrescens and Acacia tortilis, across sites that had undergone very different histories of attack from large herbivores while fire had been absent for at least 13 y. We show that heavily browsed saplings have higher regrowth abilities, twice the number of stems produced by the main root crown and twice the root diameter at 5 cm soil depth, than lightly browsed saplings. This suggests that Acacia saplings are resilient to chronic herbivory and show high morphological plasticity. However, we show that mammalian herbivores can strongly limit sapling recruitment to mature size classes and possibly affect variation in sapling density between heavily and lightly browsed sites. Further studies should investigate whether the persistence of the sapling bank can be ascribed to the "storage effect" by which a plant's reproductive potential is "stored" in a suppressed growth form until a window of opportunity allows rapid maturity. Des formes réduites de croissance d'espèces ligneuses sont communes lorsque le feu et les herbivores sont des forces majeures de l'écosystème comme dans les savanes africaines. Néanmoins les formes réduites de croissance d'espèces ligneuses ont reçues peu d'attention dans les études écologiques et ce malgré leur importance dans le maintien de la viabilité des populations. Nous avons mesuré une série de traits morpho-fonctionnels et examiné les variations de la densité de plants de formes réduites de croissance (référés ci-dessous en tant que gaules) de deux espèc

关键词： yellow mongoose   rangeland   individual-based model   shrub encroachment   spatial explicit   structural diversity  

摘要： In arid and semi-arid savannas, species diversity is strongly influenced by structural diversity, which in these systems is characteristically formed by woody vegetation. Shrub encroachment, associated with overgrazing by domestic livestock, changes the structural diversity and hence affects biodiversity. Many investigations have been carried out with focus on the structure building trees, but little is known about the importance of shrubs. Here, we present a spatially explicit and individual-based population model for analysing the influence of shrub encroachment on the occurrence of yellow mongooses (Cynictis penicillata) in the Southern Kalahari, South Africa. This analysis is based on field investigations in Southern Africa. The results of the modelling study are in line with the results of a field study, in which the same unimodal relationship between shrub cover and yellow mongoose abundance was found. The model could explain this relationship by the need of shrubs as protective structures on the one hand, and the need of foraging habitat in the grass matrix on the other hand. To evaluate the factors influencing the population dynamics at different levels of shrub encroachment we carried out an extensive sensitivity analysis. Finally, we determined a range of existence of the yellow mongoose for various shrub covers. Model results indicate a lower and an upper limit of critical shrub densities at 1% and 38%, respectively. These limits indicate the range in shrub cover allowing the persistence of the yellow mongoose in the Southern Kalahari. (C) 2007 Elsevier B.V. All rights reserved.

关键词： 哺乳动物   进化树   进化论   南美洲   博物学   袋鼠   袋狼  

摘要： 在方舟子先生的《进化论简史》一书中，有这样一段表述：当博物学家在澳洲和南美洲见到袋鼠、袋狼、袋熊、袋鼬、袋貂、袋獾等等闻所未闻的动物，就不免奇怪为什么上帝只在这里创造出有袋类哺乳动物。这并非那里的环境是为有袋类而设的，因为当移民们给这些地方带去高等哺乳动物后，

关键词： 完全基因组   系统发育树   组合向量   熵密度分布   对数关联距离  

摘要： 线粒体完全基因组是一种构建脊椎动物系统发育树的非常重要的数据资源.该文中我们应用基于非序列比对的熵密度分布方法结合对数关联距离对64种脊椎动物的线粒体完全基因组进行分析处理并构建系统发育树,产生的树将所选择的生物体分为三个大类:哺乳类(Mammalia)、鱼类(Fish)和初龙下纲(包括鸟类(Birds)和爬行类(Reptiles)),其拓扑结构与当前已知的用传统方法产生的树相似.

关键词： body size   carbon quality   ecological stoichiometry   herbivory   leaf chemistry   nitrogen   phosphorus   plant-insect interactions   Quercus  

摘要： 1. Environmental heterogeneity created by prescribed burning provided the context for testing whether the distribution of an oak specialist (the lace bug, Corythuca arcuata) could be explained by stoichiometric mismatches between herbivore and host plant composition. 2. Field observations showed that lace bug density was seven-fold higher in frequently burned than in unburned units. 3. Lace bug density did not increase with leaf nutrient concentrations, but was instead associated with higher light levels, higher concentrations of leaf carbon (C), lignin and total phenolics, and lower levels of cellulose. In addition, lace bugs reared on high-light leaves had higher levels of survivorship than those fed on low-light leaves. 4. Sampling restricted to full-sun leaves was used to test whether fire-related changes in leaf nitrogen (N) and phosphorus (P) concentrations have a secondary influence on lace bug success. This sampling provided only limited evidence for nutrient limitation, as decreases in leaf N and P were associated with an increase in lace bug mass but a decrease in density. 5. It is concluded that burning probably promotes lace bug population growth by increasing canopy openness, light penetration, and the availability of C-based metabolites, and thus simple stoichoimetric mismatches between herbivores and host plants are not of primary importance in this system.

关键词： key resource   population regulation   rainfall   savanna   waterholes  

摘要： In arid and semiarid environments surface-water strongly constrains the distribution and abundance of large herbivores during the dry season. Surprisingly, we know very little about its variability in natural ecosystems. Here we used long-term data on the dry-season occurrence of water at individual waterholes to model the surface-water availability across Hwange National Park, Zimbabwe, under contrasted climatic and management scenarios. Without artificial pumping only 19.6% of the park occurred within 5 km of water under average climatic conditions. However surface-water availability was strongly influenced by annual rainfall, and over 20 years the variability of the surface area of the park occurring within 5 km of water was slightly larger than the variability of rainfall. This contrasts with the usual buffered response of vegetation production to rainfall fluctuations, and suggests that the variability in dry-season foraging range determined by surface-water availability could be the main mechanism regulating the population dynamics of large herbivores in this environment. Artificial pumping increased surface-water availability and reduced its variability over time. Because changes in surface-water availability could cause the greatest changes in forage availability for large herbivores, we urge ecologists to investigate and report on the variability of surface-water in natural ecosystems, particularly where rapid climate changes are expected.