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莫莫格保护区的迁徙白鹤 总被引:1,自引:0,他引:1
吉林省莫莫格保护区位于嫩江下游,界于北纬45°42′—46°19′、东经122°27′—124°4′之间。该区面积144000公顷,其中三分之二以上为沼泽湿地是白鹤(Grus leucogeranus)迁徙途中重要停歇地之一。在1983年秋—1986年春,我们对保护区境内停歇白鹤的迁徙期与数量,分布与生境,种群组成进行了连续三年考察,发现并查清了该区的白鹤资源,为进步观察研究该区白鹤迁徙习性提供了基础资料。 相似文献
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红碱淖湿地遗鸥及水鸟的种群和分布研究 总被引:2,自引:0,他引:2
红碱淖湿地位于中国候鸟迁徙的主要路线上,水鸟分布较为集中,是遗鸥、大天鹅等珍稀水鸟的重要迁徙停歇地和繁殖地。通过对红碱淖湿地遗鸥及水鸟的种群和分布进行了8 a的实地调查和研究,统计分析了红碱淖2001~2007年的遗鸥和水鸟的种群数量动态变化。研究结果表明2007年红碱淖湿地的遗鸥繁殖巢数达5 036巢,种群数量10 072只,已成为全球最大遗鸥种群,在此基础上,还总结了红碱淖湿地7目14科55种水鸟的分布和保护价值,为水鸟的保护和管理提供了依据,对红碱淖湿地遗鸥及水鸟的保护具有重要意义。 相似文献
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2009年3月,采用样线法、样点法对辽宁双台河口自然保护区内迁徙停歇的丹顶鹤进行观察监测,确认并用GPS定位其停歇地;通过样方法、因子测定法进行对其停歇生境进行实地测量与分析。结果表明:(1)芦苇沼泽是丹顶鹤主选的停歇生境,占到96.4%;(2)丹顶鹤停歇地与火烧地的距离小于25 m,在火烧地边缘活动,或者停在火烧地中;(3)丹顶鹤一般会选择油井距离大于1 km处作为停歇地(100%);(4)丹顶鹤距明水面的距离较近,便于获取食物与水等;(5)频繁区对丹顶鹤影响明显。影响丹顶鹤的停歇地选择的因素既有自然因素如植被环境和明水面,也有人为因素如火烧和油井乃至道路。针对不同因素的空间分布,丹顶鹤的迁徙停歇地选择也具有一定的选择性。 相似文献
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在意大利中部的观察点,我们对秋季向非洲迁徙的白头鹞(Circus aeruginosus)和鹃头蜂鹰(Pernis apivorus)的跨海迁飞行为进行了研究.其中白头鹞大部分为成鸟,鹃头蜂鹰大部分是亚成鸟.研究内容包括跨海迁徙行为与风向、昼间迁徙时间、集群和年龄的关系.尽管鹃头蜂鹰不如白头鹞适合长距离跨海飞行,但它们集群迁徙时多远离海岸.两种鸟中只有很少个体选择沿海岸飞行.在无风天气,白头鹞像单独迁徙的鹃头蜂鹰一样,选择跨海飞行,而不是中途停歇或飞回陆地的断续迁徙,在逆风情况下则相反.而鹃头蜂鹰集群迁徙时的飞行策略不受风向影响.两种鸟在上午均选择跨海飞行而不是断续迁徙,下午则相反.鹃头蜂鹰的跨海迁飞行为与年龄相关,其成鸟很少跨海飞行.本研究证实鹃头蜂鹰迁徙过程中集群行为对其跨海迁飞的影响极为显著.不同年龄鹃头蜂鹰的跨海迁飞倾向不同,缺乏经验的亚成鸟和年轻成鸟选择高能量消耗的长途(跨海)飞行,而不是具中途停歇地的短距离断续迁徙. 相似文献
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甘肃盐池湾国家级A然保护区黑颈鹤繁殖习性的观察 总被引:6,自引:0,他引:6
2007年4月-2009年10月,在甘肃盐池湾国家级自然保护区对黑颈鹤繁殖习性进行了观察.结果表明,黑颈鹤每年4月迁徙至甘肃盐池湾国家级自然保护区进行繁殖,常活动于沼泽、湖泊、湿地一带,每年迁徙至保护区的黑颈鹤约30~40只,至10月中旬离去.通常一雄一雌制,迁徙时集中后成群离去.在甘肃盐池湾国家级自然保护区居留期约为180d左右. 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献