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1.
白尾地鸦(Podoces biddulphi)仅分布于新疆塔克拉玛干沙漠沙漠之中,为中国特有物种.目前有关这个种的现状和生态报道较少.自1988年以来,作者在塔克拉玛干沙漠腹地对白尾地鸦种群状况、分布、繁殖生态等进行了系统的研究.并对沙漠化造成白尾地鸦"东扩"进行了分析和讨论.  相似文献   

2.
There is a possibility that classical swine fever (CSF) virus outbreak has negative impacts on wild boar. To adequately manage native wild boar populations, wildlife managers need to gather the field data on wild boar and implement population management practices. We aimed to report the relative abundance index of wild boar before and after this outbreak. Our results showed that relative abundance index declined from 2017 (8.88 wild boars/100 trap days) to 2019 (2.03 wild boars/100 trap days), because of the negative impact of this virus and continuous culling programs. Although the eradication risk from the synergistic effect is low, wildlife managers need to consider the relationship between the trade-off between the risk of CSF and the conservation ecology risk of native species eradication.  相似文献   

3.
中国生态环境变迁的原因、影响及对策初探   总被引:3,自引:2,他引:1  
探讨了中国历史时期生态环境变迁的原因和影响,利用社会学、现代农业科技及恢复生态学的原理和方法提出应当采取的措施。  相似文献   

4.
Fossil evidence indicates an association between human beings and animals dating back at least half a million years. Today, this relationship remains strong, as evidenced by millions of visits to zoos annually, high rates of pet ownership, and the economic prosperity of the pet industry. A review of the literature indicates that human-animal interactions can remarkably enhance human physical health and psychological well-being. Yet despite reported benefits and public enthusiasm for animal-related activities, human affiliation with animals and nature is rapidly on the decline largely owing to a shift toward industrialized city living. Future research should not only continue to examine the mental and physical health implications of companion animal ownership, but also the ways to most successfully incorporate them into modern lifestyles and communities.  相似文献   

5.
6.
Juan J.SOLER 《中国鸟类》2012,3(4):259-273
协同进化理论的中心思想,包括巢寄生者与其宿主之间共进化关系的理论,认为时间和空间模式可揭示一些关于生态和进化动态方面的重要信息。例如,关于遗传方式和基因流在决定由寄生导致的宿主所受选择的局域模式(如拒绝卵)以及因宿主的选择压力导致的寄生者所受选择模式(如模拟卵)中所起的作用,种群的遗传结构水平为此提供了重要信息。此外,随空间变化的非生物(如气候条件)和生物(动物的表型特征)因素可能还会直接或间接影响宿主和寄生者的种群及其相互作用。通过查阅文献,我们发现大量的证据支持时间及空间上的非生物环境对寄生者和宿主卵的形态及模拟程度有重要影响。而且,有研究表明,随地理和(或)时间而变化的特殊的宿主生活史特征可能会影响新宿主最初被利用的概率以及宿主与寄生者间共进化的方向和速度。本文全面总结了以往研究中关于寄生者和宿主之间相互作用的时空模式。该时空趋势以及拒卵行为的遗传学依据和基因流的显著作用,与协同进化的动态特征相一致。然而,基因流和寄生者宿主丰富度的时空格局变化可能会导致宿主和寄生者频繁产生在形态上与直觉相反的关系(如极少或者没有模拟),这或许说明了适应的局限性。我们列举了未来需要解决的一系列科学问题,认为关于寄生者和宿主的研究在检测协同进化的地理学理论以及其它一些假说中扮演着关键角色。  相似文献   

7.
地下啮齿动物种群生态学研究经常需要对动物个体进行标记,而传统的剪耳、剪趾标记法会造成动物伤害、影响动物行为等,与动物福利相悖。利用PIT标签于2014年秋季在祁连山东段标记高原鼢鼠30只,研究高原鼢鼠种群密度及越冬后体重、体长和尾长变化。结果表明,样地内高原鼢鼠估算种群密度为44只/hm2;越冬后高原鼢鼠平均体重为222.07g,显著高于越冬前平均体重193.74g,平均体长为19.4cm,显著高于越冬前平均体长18cm;雌性与雄性的体重增长率无显著性差异(P0.05)。被动式电子标签同时可适用于地下啮齿动物的种群生态学研究,是地下啮齿动物种群生态学研究中的一项新型技术手段。  相似文献   

8.
龙须草种群增长和产量形成的年际比较研究   总被引:2,自引:1,他引:1  
通过对不同移栽密度龙须草种群茎蘖数量年际变化、绿叶数量年际变化、产量年际变化的研究,结果表明不同移栽密度对龙须草种群速生丰产群体的建立影响极大.合理的移栽密度对龙须草种群增长和产量形成具有重大意义.  相似文献   

9.
啮齿动物是草地生态系统中的重要成分.监测啮齿动物种群动态对于草地生态系统小型哺乳动物的生态学研究及草地鼠害控制均具有重要的意义.目前国内外对啮齿动物的种群监测主要以铗捕法、笼捕法为主,既费时又费力.红外相机技术的应用可弥补这一缺点,然而关于红外相机技术测度荒漠小型啮齿动物种群数量的研究并不多见.本研究采用红外相机陷阱法...  相似文献   

10.
鸭茅生理生态及育种学研究进展   总被引:5,自引:2,他引:5  
彭燕  张新全 《草业学报》2005,14(4):8-14
对鸭茅生理、生态及育种的国内外研究进展进行综述.结果显示,鸭茅适宜于气候凉爽(日均温低于25℃)、土壤水分充足(田间持水量78%~84%)、土壤肥力较高(含氮量为60~80 mg/kg土,N、P、K比率为6∶1∶2)的生境,且短日照和低温条件有利于诱导开花.鸭茅的耐盐性较差,抗寒性及抗病性则因原产地不同而差异显著,对夏季干旱表现为半休眠和不适应.但鸭茅竞争适应能力较强,可与部分豆科草和禾本科草形成稳定、高产的混生群落,适宜放牧、刈割,且通过人工摘顶可提高人工草地中鸭茅种群的适应性.近20年来,通过抗性选育、组织培养及转基因技术等方法已经获得大量优良的品种.我国鸭茅栽培应用日益广泛,但严重缺乏相应配套技术和满足生产不同需求的品种.  相似文献   

11.
The lesser pouched rat, Beamys hindei, is a small rodent that is patchily distributed in the Eastern Arc Mountains and coastal forests in East Africa. The ecology of this species and its current distribution in coastal forests is not well known. Therefore, we conducted a study in selected coastal forests to assess the current distribution of the species and to investigate the population ecology in terms of abundance fluctuations and demographic patterns. Assessments of the species distribution were conducted in 5 forests through trapping with Sherman live traps. Data on ecology were obtained from monthly capture–mark–recapture studies conducted for 5 consecutive nights per month in two 1 ha grids set in Zaraninge Forest over a 2‐year period. The results indicate the presence of B. hindei in 3 forests where it was not previously recorded. The population abundance estimates ranged from 1 to 40 animals per month, with high numbers recorded during rainy seasons. Reproduction patterns and sex ratios did not differ between months. Survival estimates were not influenced by season, and recruitment was low, with growth rate estimates of 1 animal per month. These estimates suggest a stable population of B. hindei in Zaraninge Forest. Further studies are recommended to establish the home range, diet and burrowing behavior of the species in coastal forests in East Africa.  相似文献   

12.
1. Poultry keeping in the UK hardly existed as an industry of any sort prior to the 1890s. Annual consumption per capita was 100 eggs and around 1000 M eggs were imported from countries all over the world.

2. The Utility Poultry Club was formed in 1897 and shortly afterwards the first laying trial was held near Northallerton.

3. Until 1920 little was done in the way of giving advice or training to poultry keepers or farmers, but in that year the National Institute of Poultry Husbandry was set up at Harper Adams College.

4. Egg marketing was a haphazard affair until in 1929 a National Mark Scheme was devised in an attempt to streamline distribution, so that UK eggs could compete with foreign imports, some of which were marketed here fresh, clean and graded. This could not be said for the bulk of home produced eggs until that time.

5. With the practical application of the science of genetics to poultry breeding the concept of the simple laying trial gave way to progeny test trials. By 1986 these have become international rather than national—a reflection of the international nature of the breeding industry.

6. The pattern of poultry diseases has changed radically in the 40 years since 1945. The growth of intensive and controlled environment housing produced its own problems, which the industry has largely learned to control.

7. The pre‐war table poultry industry was largely based on a premium product specially bred from such birds as Light Sussex, Dorkings and Faverolles and, at the lower end of the market, surplus cockerels from the commercial layer trade were used. The broiler industry was born around 1954 with the end of feedings tuff rationing.

8. The illustrations trace the development of extensive housing and also some early cage units which, until the early 1950s, were always single bird cages.

9. A brief paragraph is included on the history and development of the turkey industry; it is included to demonstrate its parallel development with the broiler industry, but would merit a paper of its own.  相似文献   


13.
Haemaphysalis longicornis is the only tick in New Zealand that infests livestock. Throughout its range H. longicornis is exposed to and exhibits tolerance to a wide range of environmental conditions, although it flourishes more in moist, warm-temperate environments. This review examines aspects of the biology, physiology and ecology of H. longicornis that determine its distribution and seasonal activity in New Zealand, based on laboratory and field studies. Examples are also drawn from studies outside New Zealand for comparative purposes, especially in the context of seasonal activity as seen in less temperate latitudes. The tick is able to withstand a wide range of temperature, from its developmental threshold of ~12°C to nearly 40°C at its lethal limit, but its tolerance of dehydration is less wide, especially in the larva and adult, the former especially being the stage that largely determines suitable biotopes for the tick and its present distributional limits.

The importance of H. longicornis to the New Zealand livestock industry has recently increased through the establishment and spread of Theileria orientalis Ikeda among dairy and beef cattle, although the tick has always posed production-limiting problems for cattle, deer and to a lesser extent, sheep. The tick's role as a vector of theileriosis and how aspects of the tick's biology affect the spread and maintenance of this disease are discussed. It is proposed that, of available wildlife hosts, the brown hare with its wide-ranging habits, is an important disseminator of ticks.

Currently control of ticks is difficult partly because of their wide host range, overlapping activity periods of stadia, and also because the greater part of their annual cycle is spent on pasture. This means that acaricides alone do not satisfactorily reduce tick populations or provide comprehensive protection to stock, so integrated management combining pasture management with good husbandry and chemical prophylaxis is advocated.  相似文献   


14.
黄河首曲流域草地生态与自然环境退化成因及对策研究   总被引:3,自引:3,他引:3  
近50年来黄河首曲流域草场退化、沙化,水土流失,生物多样性减少,生态系统功能弱化.分析了黄河首曲流域气候、生态观测资料及统计资料,结果表明:造成生态与自然环境退化的主要原因是气候变化和环境蠕变.黄河首曲大部分区域降水量年际变化呈下降趋势,气温年际变化呈上升趋势,增温速度均大于全国增温速度.草地年干燥指数呈显著上升趋势,20世纪80年代末至2004年明显趋于干旱化,气候变化是草地生态退化的自然诱发因素.超载过牧、滥采乱挖、人为破坏、生物链失衡等环境蠕变是造成生态退化的人为因素.二者共同作用导致黄河首曲流域草地与湿地生态与自然环境退化.控制放牧、防止滥采乱挖、建立自然生态保护区是维护该区域生态系统平衡的措施.  相似文献   

15.
16.
江河源区退化天然草地的恢复及其生态效益分析   总被引:16,自引:6,他引:16  
根据天然草地退化程度的差异,采用松耙 补播 施肥 封育(退化较严重的草地)、封育 施肥(轻度退化草地)等措施,植物群落物种组成、多样性等特征值及其植被盖度发生明显变化.研究第2年结果表明,物种数封育 施肥处理最高(32种),对照居中(26种),补播 施肥处理最低(13种);多样性指数大小依次为封育 施肥(3.126)、对照(2.819)、补播 施肥(1.494);均匀度指数大小依次为封育 施肥(0.902)、对照(0.865)、补播 施肥(0.582);群落总盖度大小依次为封育 施肥(85.9%)、补播 施肥(79.7%)、对照(72.9%);补播 施肥 封育处理后地上生物量最大(460.65 g/m2),原生植被 封育 施肥处理居中(310.14 g/m2),对照最低(178.96 g/m2);地下生物量大小依次为封育 施肥(6 920.37 g/m2)、补播 施肥(1 458.96 g/m2)、对照(828.91 g/m2);补播 施肥 封育处理优良牧草较对照提高近50倍,杂草类减少82.81%,封育 施肥处理较对照良牧草比例提高48倍,杂草类比例减少80.46%.半人工草地通过灭除杂草和施肥相结合的示范试验表明:单纯进行灭杂,地上生物量减少,灭杂和施肥相结合不仅可提高地上生物量,而且可提高优良牧草的比例;不同处理区土壤养分含量各不相同,其中封育 施肥处理全氮、全碳、有机碳最高,对照居中,补播 施肥较低.  相似文献   

17.
The harbour seal population in the Dutch Wadden Sea decreased significantly during the last decades. Calculations based on bounty data revealed that the population decreased from about 2700 in 1950 to about 900 in 1959. Annual aerial surveys--which were carried out since that time--showed a slight increase due to the stop of hunting. However, after 1964 a new decline occurred and since 1974 the population stays at a level of about 450 specimens. During 1974 to 1978 the population dynamics of the population have been studied Frequent aerial surveys provided data on the size of the population. These data have been used in a simulation model and the birth rate and the initial juvenile mortality were calculated. During boat trips an indication of the age composition was obtained by measuring track widths. By comparing these results with similar results from a stable population in Schleswig Holstein it appeared: (1) that juvenile mortality in the first weeks in the Dutch population is higher than that in Schleswig Holstein but the overall mortality of pups in both areas in their first three months of life is of the same order; (2) that pup production in the Dutch population is low compared to the population in Schleswig Holstein; (3) that apparently immigration from elsewhere occurs. To investigate the contribution of environmental pollution to the decline of the Dutch seal population tissues of dead, stranded animals originating from Schleswig Holstein, Denmark and the Netherlands were collected and analyzed for PCBs, o,p'-DDT, p,p'-(DDT, DDE, TDE), dieldrin, aldrin, endrin, endosulfan, alpha, beta, gamma,-HCH, HCB, QCB (pentachlorobenzene), HEPO, total mercury, methyl-mercury, selenium and bromium. Considering epidemiological and experimental data on the effects of PCBs on mammalian reproduction, strong support is obtained for the hypothesis that PCBs are responsible for the decreased reproduction in seals from the Dutch Wadden Sea. if PBCs are responsible for the decrease of the Dutch seal population, measure of all North Sea countries are urgently required because these PCBs may not only be a hazard to seals but also to other animals and even man. Production and use of PCBs should be limited and used PCBs should be collected and destroyed. However, even if an immediate ban on PCB's would be effected, the effects of PCBs because of their persistent character are likely to last many years. For that reason it may be assumed that the seal population in the western Wadden Sea still faces a difficult period in the years to come. In order to lead this population through this difficult period, all possible measures enhancing its continued existence should be taken. Since the seals in the Wadden Sea form one population maximum result may be expected from measures applying to all seals in the Wadden Sea. Thus international cooperation is necessary. The following measures are proposed: Continued interdiction of hunting in order to obtain a maximum number of animals taking part in reproduction. Establishment of seal reserves and, additionally supporting seal nursery stations in order to guarantee a maximum reproductive output. However, it has to be stressed that these measures are not effective if at the same time the main cause of the decrease is not found and brought under control.  相似文献   

18.
Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patches. The ROMPA hypothesis (ratio of optimal to marginal patch area) uniquely links vole population fluctuations to the composition of the landscape. It states that as ROMPA decreases (fragmentation increases), vole population fluctuations will increase (including the tendency to display multi‐annual cycles in abundance) because decreased proportions of optimal habitat result in greater population declines and longer recovery time after a harsh season. To date, only comparative observations in the field have supported the hypothesis. This paper reports the results of the first experimental test. I used prairie voles, Microtus ochrogaster, and mowed grassland to create model landscapes with 3 levels of ROMPA (high with 25% mowed, medium with 50% mowed and low with 75% mowed). As ROMPA decreased, distances between patches of favorable habitat (high cover) increased owing to a greater proportion of unfavorable (mowed) habitat. Results from the first year with intensive live trapping indicated that the preconditions for operation of the hypothesis existed (inversely density dependent emigration and, as ROMPA decreased, increased per capita mortality and decreased per capita movement between optimal patches). Nevertheless, contrary to the prediction of the hypothesis that populations in landscapes with high ROMPA should have the lowest variability, 5 years of trapping indicated that variability was lowest with medium ROMPA. The design of field experiments may never be perfect, but these results indicate that the ROMPA hypothesis needs further rigorous testing.  相似文献   

19.
The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis), a critically endangered species, is the only cetacean species in the Yangtze River following the functional extinction of baiji (Lipotes vexillifer). To inform conservation actions, two important questions need to be addressed: what is the threshold value of survival rate, and what is the threshold value of population size? We calculate the instantaneous rate of population increase () for the Yangtze finless porpoise for various combinations of the calf and the non-calf survival rates. We also test the probability of extinction for different minimum carrying capacities for 100 and 500 years using a stable population model. The threshold value of the non-calf survival rate is never lower than 0.869, but current estimates from field data have been far below this threshold. Our model based on extinction probability and carrying capacity suggests that the threshold for the population size to persist 100 years required 113 animals, and 472 animals are required to persist 500 years. Therefore, we recommend establishing an ex situ reserve network to guarantee the minimum 100-year carrying capacity. To ensure the long-term population viability, we suggest establishing two in situ reserve zones in two lakes and their surrounding reserves to meet a minimum 500-year carrying capacity. In addition, measures to avoid further habitat fragmentation should be priority.  相似文献   

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