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1.
A set of about 25 diminutive sub-parallel scrapes in the Cretaceous Haman Formation of South Korea fit the morphology of the small theropod track Minisauripus which is also known from this formation. The scrapes are interpreted as evidence of display behavior, and suggest that the trace maker was an adult engaged in avian-like courtship behavior. Although avian theropods are also known from this formation, the scrapes are inconsistent with their foot morphology. Although large theropod scrapes have been interpreted as evidence of display behavior they are only known from North America. Thus, the scrapes described here are the first reported from Asia, and the first interpreted as evidence of display behavior in such a diminutive species. 相似文献
2.
Development of an Enzyme Immunoassay for the Detection of Mecoprop in Drinking Water and Groundwater Based on Antibodies Raised in Chicken Egg Yolk Antibodies against mecoprop were isolated from egg yolk of immunized hens and were used for the development of an enzyme-linked immunosorbent assay. We tested assay parameters (pH and concentration of buffer, incubation temperature, kind of enzyme tracer) to optimize the standard curve for mecoprop. By decreasing the pH, the detection limit was reached at a concentration of 0.35 μg/L mecoprop. The concentration for 50% inhibition (50% B/B0) was 2.8 μg/L. Dichlorprop and the methyl esters of both mecoprop and dichlorprop showed high crossreactivity (165%, 400% and 233%). Antibodies against mecoprop separated from egg yolk were compared to antibodies raised in rabbit for both sensitivity and specificity. Chicken immunoglobulins were found to be less sensitive and specific than the mammalian IgG's. 相似文献
3.
湿地生态旅游区以其生态多样性、景观多样性和物种多样性,成为许多珍稀濒危鸟类的主要栖息地和繁殖地。随着旅游开发的深入,鸟类栖息地保护及观鸟旅游已成为湿地旅游开发的两个重要方面。为确保湿地生态旅游区的可持续发展,选取盐城丹顶鹤湿地生态旅游区为研究对象,根据鸟类的栖息要求,营建相应的栖息生境,并对观鸟旅游方式做了初浅的探讨,以期对以鸟类栖息地保护为主的湿地规划提供借鉴。 相似文献
4.
S. I. Karchner S. W. Kennedy S. Trudeau M. E. Hahn 《Marine environmental research》2000,50(1-5):51-56
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related planar halogenated aromatic hydrocarbons (PHAHs) are highly toxic to most vertebrate animals, but there are dramatic species differences in sensitivity, both within and among vertebrate classes. For example, studies in cultured avian hepatocytes have revealed differential sensitivity of birds to PHAHs [Kennedy et al. (1996). Toxicol. Appl. Pharmacol., 141, 214-230]. Differences in the characteristics or expression of the aryl hydrocarbon receptor (AHR) could contribute to these species differences in PHAH responsiveness. To investigate the molecular mechanism of differential PHAH sensitivity, we have begun to characterize the AHR in white leghorn chicken (Gallus gallus), Pekin duck (Anas platyrhynchos), and common tern (Sterna hirundo), as well as an amphibian, mudpuppy (Necturus maculosus). Partial AHR cDNAs encompassing the helix-loop-helix and PAS domains were cloned and sequenced. Comparison of amino acid sequences in this region indicated a high degree of sequence conservation among the bird species (97% amino acid identity). The percent identity between bird sequences and either mouse or mudpuppy was lower (79%); the mudpuppy AHR was 74% identical to the mouse AHR. Phylogenetic analysis of these and other AHR amino acid sequences showed that the bird and mudpuppy AHRs were more closely related to mammalian and fish AHR1 forms than to fish AHR2. Future studies include the in vitro expression and functional characterization of AHRs from these and other non-mammalian vertebrates. 相似文献
5.
Joanna Burger 《Estuarine, Coastal and Shelf Science》1983,16(2):191-216
The distribution and abundance of gulls were examined at Jamaica Bay Wildlife Refuge (New York) from 31 May 1978 to 31 May 1979. Gulls were found to be affected by tidal, temporal and weather-related factors. The distribution of gulls was affected primarily by tidal factors on the bay, and by temporal (seasonal, circadian) and weather-related factors on the freshwater ponds. The most important weather-related factors were temperature, wind velocity and wind direction. Herring (L. argentatus), great black-backed (L. fuscus) and ring-billed gulls (L. delawarensis) fed on the bay at low tides, and used the ponds at high tide. Laughing gulls (L. atricilla) fed on the bay at low tide and on rising tides. Herring and great black-backed gulls were present all year, but were most abundant in the winter, ring-billed gulls were abundant in spring and early fall, and laughing gulls were present in the summer following the breeding season but were absent in winter. Gulls used the ponds during high velocity, north winds, when they usually rested or preened. Multiple regression models were used to determine the factors explaining the variability in the numbers of gulls. Temporal variables were important contributors to accounting for the variability in the numbers of great black-backed and herring gulls only; tidal variables were significant for great black-backed and herring gulls on the bay, and for ring-billed and laughing gulls on all areas; and weather variables were significant for all species. 相似文献
6.
广东湛江红树林国家级自然保护区位于中国大陆最南端的湛江市,分布有全国最大面积的红树林。红树林生态系统生物多样性丰富,非常适宜鸟类生存,而保护区地处西伯利亚-澳大利亚候鸟迁徒路线,每年都有大量候鸟在红树林区内栖息繁衍。如何保护这些珍贵鸟类及红树林栖息地是保护区的主要工作之一。介绍了湛江红树林保护区鸟类资源特点及变化情况,并提出了一些可行的保护措施。 相似文献
7.
A. Si BachirF. Ferrah C. BarbraudR. Céréghino F. Santoul 《Journal of Arid Environments》2011,75(11):1232-1236
This study identifies new information on the recent distribution of an invasive bird species, the Cattle Egret Ardea ibis, in Algeria. Breeding and wintering distributions as well as breeding numbers were obtained from large-scale surveys in 1999 and 2007, and from historical data. Between 1999 and 2007, the total number of colonies found increased from 51 to 87, and most were located in the northern part of the country. The breeding distribution area, confined to the coastal areas in the 1970s, has shifted further south, and reached the northern part of the Sahara since the 2000s. Most colonies were established during the period 1980-1995. The oldest colonies were generally larger than the recent ones. The number of colonies increased by 83% between 1999 and 2007 in the 12 administrative units (wilayas) surveyed. The number of breeding pairs increased from 7765 in 1999 to 28544 in 2007, corresponding to an annual population growth rate of 17.7%. The changes in distribution and population dynamics since the 1970s and the potential factors affecting these changes are discussed. 相似文献
8.
我国鸟类资源丰富,但缺乏专业的鸟类救护机构,故缺乏成熟系统的鸟类救治经验。鄱阳湖是我国重要的鸟类栖息地,由于各种原因,很多鸟类会被救助。研究以鄱阳湖地区救护鸟类为对象,对2012-2014年期间救护档案进行归纳整理和统计分析。结果表明:救护鸟类总共有15只,其中13只为成年鸟,2只幼鸟。救护鸟类中雁属的数量最多,达到7只。救护鸟类的来源主要包括:鄱阳湖自然保护区管理局移送、鄱阳湖自然保护区监测站移送、林业局野生动物保护站移送和市民移送4个方面,其中管理局送过来的鸟类数量最多,达到了10只,占总数的66.7%。救护鸟类所受伤害症状主要有3类:骨折、中毒和外伤。造成伤害的危险源可分成4类:天网、投毒、天敌和其他。救治成活率达到了80%。通过本研究,为野生鸟类保护和救助提供了参考。 相似文献
9.
鸟类与环境变迁关系剖析 总被引：4，自引：0，他引：4
王直军 《云南地理环境研究》1991,3(2):82-89
本文所涉及的是将鸟类研究作为一种手段来认识生态环境问题。西双版纳勐仑地区原始森林面积减少以及人为活动对生态环境的影响,鸟种趋于减少,不同生态对策的鸟类情况各异。k-对策者受害最大,而极端r-对策鸟种在人为影响的环境中能获得优势地位。研究表明对环境的保护、自然资源的利用,必须从系统的观点全面考虑,西双版纳地区特别要着重保护好热带原生林。改善人工林层次结构,建立多层次人工生态群落可起到较好的环境保护作用,并能维持更多生物种类,发挥它们在生态环境中的有效功能。 相似文献
10.
Contamination and toxic effects of persistent endocrine disrupters in marine mammals and birds 总被引：9，自引：0，他引：9
Tanabe S 《Marine pollution bulletin》2002,45(1-12):69-77
In recent years, several species of marine mammals and birds have been affected by uncommon diseases and unusual mortalities. While several possible causative factors have been attributed for these events, a prominent suspect is exposure to man-made toxic contaminants. Particularly, some of these man-made chemicals can disrupt normal endocrine physiology in animals. At CMES, our studies focus on exposure and toxic effects of endocrine disrupting chemicals, particularly organochlorines, in higher trophic level wildlife. Endocrine disrupting chemicals, such as organochlorine insecticides, polychlorinated biphenyls, organotins etc. are found in tissues of a wide variety of wildlife. Extremely high concentrations have been found in animals afflicted with diseases and/or victims of mass mortalities. Elevated contamination by organochlorines has been found in open sea animals such as cetaceans and albatrosses, which seemed to be attributable to their low capacity to metabolize toxic persistent contaminants. Significant correlations between biochemical parameters (serum hormone concentrations and cytochrome P450 enzyme activities) and residues of endocrine disrupting chemicals were found in some species of marine animals, which indicates that these chemicals may impose toxic effects in animals even at the current levels of exposure. In general, water birds and marine mammals accumulated the dioxin-like compounds with much higher concentrations than humans, implying higher risk from exposure in wildlife. The future issues of endocrine disrupting chemicals in humans and wildlife will have to be focused in developing countries. 相似文献