首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
种群密度是生物种群最基本的数量特征.标志重捕法是估算动物种群密度的常用方法.在野生动物保护、农林业害虫、害兽的监控与防治、渔业资源的评估、利用与保护上有重要应用。鉴于在中学现有条件下。对兽鸟鱼虫进行实际的标志重捕实验难以展开,在新课程教学实践中,我们反复研究了几种版本中标志重捕法的说明,设计并实施了如下标志重捕法的模拟实验,教学效果反馈很好。  相似文献   

2.
根据2010年3月—11月在千岛湖地区2个岛屿上社鼠(Niviventer confucianus)的标志重捕数据,分别用Jolly-Seber法、修正Lincoln指数法、Schnabel法和MNA法计算两个岛屿上社鼠种群数量,并深入探讨在陆桥岛屿环境下估算社鼠种群数量的适用方法。研究结果显示,在满足Jolly-Seber法的条件下,通过该方法计算的结果与修正Lincoln指数法无显著差异。但在野外实验中,并不是所有的重捕数据都满足Jolly-Seber法的条件,而且该方法不能估算头尾两月的数量。因此,修正Lincoln指数法更适于估算陆桥岛屿环境下社鼠的种群数量。可为今后开展陆桥岛屿环境下鼠类种群生态学研究奠定基础。  相似文献   

3.
李月辉 《生物多样性》2021,29(12):1700-640
大中型兽类种群数量的估算是动物生态学中重要的基本问题, 受到研究者、管理者和公众的共同关注。国际上从20世纪中期开始研究该问题, 已出现了多种研究方法和相应案例, 且还在快速发展, 但世界各地仍有很多物种的种群数量尚未知晓。在我国, 从20世纪80年代开始调查大中型兽类种群数量, 取得了重要进展, 也还有很多物种的种群数量尚不清楚。因此, 有必要归纳国际上种群数量估算的研究进展, 同时, 总结国内研究的现状、优势和趋势, 供研究者参考。本文首先选择估算大中型兽类种群数量的原理、数据来源和模型这3个要素归纳出简明的研究框架, 将现有的多种方法置于其中予以阐述。在该框架下, 根据估算原理分为4大类方法, 为距离取样法、标志重捕法、基于遇见率法和遥感影像直接计数法。针对每一大类方法, 论述其基本原理模型和模型假设, 说明能实现该原理的相应数据来源(视觉观测、红外相机拍摄、DNA微卫星识别、卫星定位跟踪、声音监测或遥感影像)的特点及如何实现该原理, 评价其适用性及优缺点, 并选择其中具有可比性的方法予以比较评价。其次, 参照该研究框架, 总结我国的研究现状, 分析未来发展的优势和趋势: 我国的红外相机数据积累充分, 可以发展以此为数据源的距离取样法、标志重捕法和基于遇见率法; 发展以粪便样品为数据来源的距离取样法和粪便DNA标志重捕法; 相比地面调查数据, 获取高分辨率遥感影像数据更容易, 尽量以此估算符合适用条件的大中型兽类的种群数量。最后, 本文提出了适用于我国大中型兽类种群数量的估算方法的选择流程, 供研究者参考。  相似文献   

4.
Jolly - Seber 法估算长爪沙鼠种群参数的适用性探讨   总被引:5,自引:3,他引:2  
以2000 年6 月~10 月群居性长爪沙鼠野生种群的标志重捕资料为依据, 采用Jolly - Seber 模型估算了该鼠种群参数, 结果表明, 长爪沙鼠个体间具等捕性(Leslie 法检验) , 研究期间取样个体的重捕率平均为89.7 %(77.4 % ~ 100 %) ; 参数估计结果具有合理的生物学意义, 认为采用该模型估算长爪沙鼠种群参数是适用的。  相似文献   

5.
Jolly—Seber法中种群存活率估算的探讨   总被引:2,自引:1,他引:2  
在Jolly-Seber法中,存活率为其核心参数之一。一些作者指出,采用Jolly-Seber法估算标志重捕数据有时候会出现存活率大于1的情形。本文就这一情形做了相应的分析,认为产生这一现象的原因为标志个体间不具有等捕性或等存活率所致。在设计标志重捕取样的野外调查中,应设法提高重捕率以增加估计精度。  相似文献   

6.
Jolly-Seber法中种群存活率估算的探讨   总被引:1,自引:0,他引:1  
在Jolly Seber法中 ,存活率为其核心参数之一。一些作者指出 ,采用Jolly Seber法估算标志重捕数据有时候会出现存活率大于 1的情形。本文就这一情形做了相应的分析 ,认为产生这一现象的原因为标志个体间不具有等捕性或等存活率所致。在设计标志重捕取样的野外调查中 ,应设法提高重捕率以增加估计精度  相似文献   

7.
韦怡  姜广顺 《生物多样性》2022,30(9):21551-242
虎(Panthera tigris)和豹(P. pardus)及有蹄类猎物的种群数量监测是虎豹保护的核心任务, 也是制定有效管理、保护和恢复措施的基础。近年来, 国内外用于虎豹种群数量监测的方法主要有: 信息网络收集法、基于标志重捕模型的红外相机调查法和非损伤采样粪便DNA分析技术; 有蹄类猎物的监测方法主要有: 样线法、样带法、大样方法、红外相机调查技术和非损伤性遗传标志重捕法。每种监测方法基于的假设前提和生态学原理不同, 监测结果的准确度也不同。由于监测物种的生物学特征、种群分布状况、监测目标和空间尺度或环境因素各异, 每种方法的适用性也不同。本文从野外调查设计、数据收集、处理分析等方面对虎豹及其有蹄类猎物数量监测方法的应用过程和统计原理进行了介绍, 分析了各种监测方法的优缺点, 并针对在虎豹监测中相机布设密度过大可能造成的伪重复抽样, 以及应用虎豹监测设计的自动相机监测替代猎物种群监测数量的评估等不科学的方面进行了探讨和建议。  相似文献   

8.
为了获得天山马鹿Cervuselaphus songaricus喀拉乌成山种群数量,并评估不同种群数量统计方法之间的差异。2010~2012年利用样线法、粪堆计数法以及非损伤性标记重捕法对喀拉乌成山的天山马鹿种群数量进行研究,发现样线法估计的种群数量最低,仅为1.316~1.656头/km2;而非损伤性标记重捕法获得的种群数量最高,为2.075~3.11头/km2;粪堆计数法获得的数据居中,为1.422~2.844头/km2,说明不同的方法之间很难具有可比性。  相似文献   

9.
1980—1982年在青海省海北高寒金露梅(Potentilla fruticosa)灌丛地区,用标志重捕法(CMR)对自然栖息地中的根田鼠(Microtus oeconomus)进行了野外调查。本文主要分析了根田鼠种群数量变动特点和繁殖、存活及年龄结构与种群动态的关系,并试图探讨根田鼠种群的稳定机制。  相似文献   

10.
布氏田鼠种群生态研究   总被引:10,自引:5,他引:10  
武晓东 《兽类学报》1990,10(1):54-59
1985年5-l0月用标志重捕法对布氏田鼠(Microtus brandti)的种群年龄组成、幼鼠生长率和季节迁移等进行研究,共标志2786只,重捕576只,822只次。发现布氏田鼠种群的年龄组成有较明显的季节变化。其幼鼠体重的日平均生长率随年龄增加而减慢。布氏田鼠还有季节迁移现象。  相似文献   

11.
A new polynitro cage compound 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptcyclo [5.5.1.1(3,11).1(5,9)] pentadecane (NNNAHP) was designed in the present work. Its molecular structure was optimized at the B3LYP/6-31 G(d,p) level of density functional theory (DFT) and crystal structure was predicted using the Compass and Dreiding force fields and refined by DFT GGA-RPBE method. The obtained crystal structure of NNNAHP belongs to the P-1 space group and the lattice parameters are a = 9.99 ?, b = 10.78 ?, c = 9.99 ?, α = 90.01°, β = 120.01°, γ = 90.00°, and Z = 2, respectively. Based on the optimized crystal structure, the band gap, density of state, thermodynamic properties, infrared spectrum, strain energy, detonation characteristics, and thermal stability were predicted. Calculation results show that NNNAHP has detonation properties close to those of CL-20 and is a high energy density compound with moderate stability.  相似文献   

12.
Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.  相似文献   

13.
14.
The variation with age of the 18 trace element mass fractions and some histological characteristics of intact prostate glands of 50 subjects aged 0–30 years was investigated by instrumental neutron activation analysis, inductively coupled plasma atomic emission spectrometry, and a quantitative morphometric analysis. Mean values ± standard error of the mean (M ± SΕΜ) for the mass fractions (in milligrams per kilogram wet tissue) of these trace elements in pre-puberty were: Al 28.5 ± 9.0, B 0.40 ± 0.11, Ba 1.48 ± 0.44, Br 10.5 ± 1.5, Ca 241 ± 30, Cl 3,203 ± 278, Cu 3.51 ± 0.89, Fe 33.7 ± 4.1, K 2,364 ± 145, Li 0.020 ± 0.004, Mg 153 ± 23, Mn 0.46 ± 0.06, Na 2,286 ± 130, P 1,391 ± 100, S 1,698 ± 132, Si 62 ± 11, Sr 0.38 ± 0.08, and Zn 27.6 ± 2.3. During puberty and postpuberty, when there is a significant increase in circulating androgens, the mean values were: Al 7.2 ± 1.4, B 0.21 ± 0.05, Ba 0.25 ± 0.06, Br 5.8 ± 1.0, Ca 433 ± 81, Cl 2,314 ± 201, Cu 1.77 ± 0.13, Fe 20.9 ± 1.6, K 2,585 ± 118, Li 0.0088 ± 0.0014, Mg 232 ± 27, Mn 0.34 ± 0.04, Na 1,875 ± 107, P 1,403 ± 98, S 1,673 ± 73, Si 22.2 ± 3.1, Sr 0.22 ± 0.03, and Zn 93.3 ± 8.9. Mean values (M ± SΕΜ) of percent volumes (%) of the stroma, epithelium and lumen in the prostate before puberty were 73.4 ± 2.6, 20.4 ± 1.7, and 4.45 ± 0.94, respectively, versus 46.5 ± 2.5, 38.5 ± 1.9, and 14.9 ± 1.2 during puberty and postpuberty. This work’s results confirm that the Zn mass fraction in prostate tissue is an androgen-dependent parameter. For the first time it has been demonstrated that the glandular lumen is a main pool of Ca, Mg, and Zn accumulation and that the stroma is a main pool of Al, B, Ba, Br, Cl, Cu, Fe, Mn, Na, and Si accumulation in the normal human prostate, for the age range 0–30 years. It was concluded that the Ca, Mg, and Zn binds tightly within the prostatic fluid, because the volume of glandular lumen reflects the volume of prostatic fluid.  相似文献   

15.
The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.  相似文献   

16.
This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.  相似文献   

17.
The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15–55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M?±?SΕΜ) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54?±?0.16, 171,400?±?4,050, 1.35?±?0.22, 140?±?11, 1,874?±?71, 0.049?±?0.011, 2,139?±?38, 5,378?±?88, 75,140?±?1,660, 1,881?±?51, 291?±?20, and 92.8?±?1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.  相似文献   

18.
《Ibis》1894,36(3):447-460
  相似文献   

19.
20.
Oral cancer is one of the main causes of cancer-related deaths in South-Asian countries. There are very limited treatment options available for oral cancer. Research endeavors focused on discovery and development of novel therapies for oral cancer, is necessary to control the ever rising oral cancer related mortalities. We mined the large pool of compounds from the publicly available compound databases, to identify potential therapeutic compounds for oral cancer. Over 84 million compounds were screened for the possible anti-cancer activity by custom build SVM classifier. The molecular targets of the predicted anti-cancer compounds were mined from reliable sources like experimental bioassays studies associated with the compound, and from protein-compound interaction databases. Therapeutic compounds from DrugBank, and a list of natural anti-cancer compounds derived from literature mining of published studies, were used for building partial least squares regression model. The regression model thus built, was used for the estimation of oral cancer specific weights based on the molecular targets. These weights were used to compute scores for screening the predicted anti-cancer compounds for their potential to treat oral cancer. The list of potential compounds was annotated with corresponding physicochemical properties, cancer specific bioactivity evidences, and literature evidences. In all, 288 compounds with the potential to treat oral cancer were identified in the current study. The majority of the compounds in this list are natural products, which are well-tolerated and have minimal side-effects compared to the synthetic counterparts. Some of the potential therapeutic compounds identified in the current study are resveratrol, nimbolide, lovastatin, bortezomib, vorinostat, berberine, pterostilbene, deguelin, andrographolide, and colchicine.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号