摘要： The availability of natural cavities for cavity-nesting waterfowl, especially wood ducks (Aix sponsa), was unknown for the regenerating forest of Sunkhaze Meadows National Wildlife Refuge, ME. An assessment of cavity availability was needed to determine if the existing nesting box program should be increased. During November to March, 1996-97 and 1997-98, I sampled 56 one-half ha random plots, stratified into 5 types (upland hardwood, upland conifer, upland mixwood, wetland conifer, and wetland hardwood) to assess availability of trees with cavities. The predominant tree species with cavities were red maple (Acer rubrum; 39%) and aspen (Populus sp.; 31%); 72% of all trees with cavities were alive. Density of nest-cavity trees/plot averaged from 1.0 plus or minus 0.4 (x plus or minus SE) in wetland softwoods to 1.9 plus or minus 0.4 in upland hardwoods. This low density of potential cavity trees and the small mean dbh (39.4 plus or minus 1.6 cm ) indicate a young forest with few suitable cavities. Forested areas, especially hardwoods near canopy openings, need to be allowed to mature to increase the number and quality of future cavities. An expanded nest box program seems justified.

关键词： Mitochondrial DNA   Phylogeny   Maximum parsimony   Taxa   Topology   Animals   Plant morphology   Nucleotide sequences  

摘要： Nuclear and mtDNA sequences from selected short-looped terebratuloid (terebratulacean) articulate brachiopods yield congruent and genetically independent phylogenetic reconstructions by parsimony, neighbour-joining and maximum likelihood methods, suggesting that both sources of data are reliable guides to brachiopod species phylogeny. The present-day genealogical relationships and geographical distributions of the tested terebratuloid brachiopods are consistent with a tethyan dispersal and subsequent radiation. Concordance of nuclear and mitochondrial gene phylogenies reinforces previous indications that articulate brachiopods, inarticulate brachiopods, phoronids and ectoprocts cluster with other organisms generally regarded as protostomes. Since ontogeny and morphology in brachiopods, ectoprocts and phoronids depart in important respects from those features supposedly diagnostic of protostomes, this demonstrates that the operational definition of protostomy by the usual ontological characters must be misleading or unreliable. New, molecular, operational definitions are proposed to replace the traditional criteria for the recognition of protostomes and deuterostomes, and the clade-based terms 'Protostomozoa' and 'Deuterostomozoa' are proposed to replace the existing terms 'Protostomia' and 'Deuterostomia'.

关键词： Elephants   Habitat quality   Kenya   Land use changes   Savanna   Wildlife  

摘要： Land use changes have been shown to have significant effects on wildlife species. Sixty three percent of the national Parks and Reserves in Kenya are located in the savannas. Because of the seasonality associated with savanna ecosystems, 75% of the wildlife species and numbers in Kenya occur in savanna nonpark areas. Therefore, conservation of wildlife in Kenya has to address the changes that are taking place in savanna areas outside parks. I studied land use changes and their effects on elephant habitat quality in Amboseli Basin, Kenya. I used visual interpretation to analyze land use changes from satellite images for 1975, 1988, and 1993. I determined that during the evaluation period, conversion of areas to agricultural land has been unidirectional. The hectarage under cultivation was 2,937, 10,950, and 24,476 for 1975, 1988, and 1993 respectively. Trend analysis seems to suggest that during the evaluation period, conversion of areas to agricultural land has followed an exponential function (R2 = 0.99) in Amboseli Basin. The area under cultivation was 6.9% of the total area studied. This is small but significant considering that agricultural land was almost exclusively located in areas that form the dry season fall back areas. Such areas are important for the survival of elephants and other species during critical periods. I developed a dry season habitat suitability index (HSI) model for the African elephant based on the density of acacia trees (# of trees > 5 cm dbh/ha) and distance (km) to natural sources of water in the basin. The amount of good quality habitat (i.e., HSI > 0.6) declined from 74,666 ha in 1975 to 54,890 ha in 1988, to 23,208 ha in 1993. This is a drop of 51,890 ha (65.5%) of good quality habitat in the basin. On the other hand, low quality habitat (HSI < 0.2) increased by 272% between 1975 and 1993. The weighted HSI values in the basin showed a decline, as did the habitat units for the 3 evaluation years. The weighted HSI declined by 0.13 bet

关键词： 结核杆菌   毒力   动物模型   菌株   感染  

摘要： 采用标准毒力的Ｈ３７ＲＶ菌株和经Ｌ－Ｊ培基传代减毒的菌株，对Ｃ５７ＢＬ／６Ｎ小鼠进行尾静脉注射和腹腔注射感染，就树造动物各器官的结核菌实验模型进行了探讨。结果表明，树造胸腔器官（肺和心脏）的动物模型以尾静脉感染为好，树造肝、脾和腹股沟淋巴结结核的动物模型以腹腔注射感染为宜。如要成功地树造结核感染的动物模型，最好将所购回的标准菌株在实验动物体内恢复毒力后再使用。

关键词： 实验动物   动物模型  

摘要： 自从1981年吴小闲等人将我国的野生树(鼠包)(Tupaia belangeri chinensis)引进实验室饲养繁殖以来,许多研究者把这种新的实验动物用于医学科研,并取得进展。树(鼠包)为小型灵长类动物,其形态、生理机能和生化代谢方面与人相似,作为动物模型可能更接近于人类情况,实验结果容易推广到人。目前,树(鼠包)在甲、乙型肝炎和睡眠生理研究上有重要用途,树(鼠包)还被用作化学致癌、黄曲霉素致肝癌以及人疱疹病毒感染的实验研究,树(鼠包)还被广泛地应用于生态学、形态学、神经生理学、寄生虫学、

关键词： 濒危动物   驯养繁殖   国家一级保护   北京南郊   人工饲养   马来熊   野生鸟类   白眉长臂猿   雌鸟   兽医院  

摘要： 在北京南郊“万亩片林”公园,有一方19公顷的野生动物领地,存活着33个濒危珍稀物种,447只(头)飞禽走兽,属国家一级保护的就达15种,76只(头)。这儿便是中国野生动物保护协会与北京市农工商开发贸易公司于1986年9月共同建立的“北京濒危动物驯养繁殖中心”。

关键词： 树河组   二叠纪   盐源   动物化石   灰岩   早二叠世   石炭纪  

摘要： 1965年,丁蕴杰等在四川盐源测制剖面时,将下二叠统底部的一套砾状灰岩地层称为树河组,并以盐源树河牛厂甘沟梁子为其建组剖面,提出该区石炭纪与二叠纪的生物共生现象。1981年,四川攀西地质大队区调三队将此套含砾地层归于上石炭统一下二叠统,以盐源树河小槽梁子剖面为其代表。1982年,詹立培等将这套砾状灰岩层位与贵州龙吟组对比,将其中生物化石称为混生动物群。近年来,我所与成都地质学院师生在盐源西部及云南宁蒗泸沽湖等地测制剖面,在相同层位上见明显的生物混杂现象,乃构造破坏后再沉积的产物。

关键词： 动物学家   动物国   玛丽   规划处   斯科特   四年   博物学家   圆木   古生物学家   鸟鸣  

摘要： <正> 一走进“树厅”的大门,你就进入了一个奇妙的世界。在这里你会觉得自己变成了一只青蛙或一只蜜蜂:你可以钻出蛋壳或茧皮;也可以观察水底的游鱼或夜行动物的行迹;还可以让蟋蟀吟唱,让恐龙鸣吼。这一奇妙世界叫作“树厅”,建造在一所百年之久的建筑里,它是由建筑师、动物学家、雕塑家、美术师和发明家共同建造的,其设计和施工用了近四年时间。“树厅”是一个让孩子们通过游戏学习自然环境知识的场所。建造“树厅”的想法是费城动物园规划处主任玛丽一斯科特·西布尔提出的。她说:“我一直在琢磨创建一种场景,使孩子们在其中对大自然感到敬畏或融为一体。我想,