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我国有分布的天鹅属所有种(Cygnusspp.)均为国家Ⅱ级重点保护野生动物,根据中华人民共和国刑法,非法猎捕、杀害珍贵濒危野生动物构成刑事犯罪。然而,天鹅死亡案件仍时有发生。本文分析2000至2016年有统计的我国天鹅死亡案件发现,每年11月至翌年1月是涉天鹅案件的高发时期;毒杀为致死主因;案件多发生于我国行政区划交界处。因此,应于迁徙越冬季节重点加强高案发地点的侦查监管;加强克百威(呋喃丹)为代表的高毒农药管控;建立迁徙季节多地区执法联动机制。  相似文献   
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为查清内蒙古乌梁素海湖泊湿地疣鼻天鹅(Cygnus olor)繁殖期和秋季迁徙前期种群数量,2014至2017年采用路线统计法和样点统计法对其进行精确计数统计,结合近十余年来的文献数据和监测记录,探讨了种群数量的变化及原因。结果显示,2015至2017年春季繁殖成鸟数量依次为84只、92只、80只,基本稳定;2014至2017年,秋季种群数量依次为411只、302只、281只、153只,逐年减少;近几年适宜繁殖地和觅食地面积不断缩小、天敌偷袭、捡蛋和投毒等因素影响亚成鸟和幼鸟的生存。根据文献和保护区监测数据,1996至2004年种群数量逐年增多,与自然保护区的建立、严禁捡蛋和没收猎枪有关,而2005至2013年因干旱缺水、水域被开发利用、芦苇(Phragmites australis)和宽叶香蒲(Typhalatifolia)面积扩增、水质恶化、富营养化加重等原因种群数量下降。研究表明,近几年乌梁素海被过度开发利用,人为干扰频繁,影响疣鼻天鹅正常繁殖栖息;栖息地的科学管理和严禁捡蛋及投毒行为,对该种群的生存及增长至关重要。  相似文献   
4.
荣成天鹅湖湿地越冬大天鹅食性分析   总被引:7,自引:2,他引:7       下载免费PDF全文
2005年12月~2006年3月以大天鹅(Cygnus cygnus)为对象,研究其越冬期间的食性,利用粪便显微组织分析法定量调查其食物组成。结果表明,大天鹅的越冬食物主要为小麦(Triticum aestivum)、海带(Laminaria japonica)和大叶藻(Zostera marina),其中,小麦的比例最大,分别占冬季食物组成的99.67%和早春的90.17%。对冬季与早春的食物组成的差异进行分析,发现大天鹅在天鹅湖保护区发生了食物替代现象。结合以往资料,认为生态污染和湿地结构性破坏导致大天鹅传统食物减少,致使食物替代现象的发生。  相似文献   
5.
Measuring the food left in experimental trays when study organisms cease feeding on them [so‐called giving‐up densities (GUDs)] is an accepted technique for assessing predation risk and disturbance. However, in natural settings, accessibility and energetic harvest costs may vary spatially, and GUDs may be confounded. In this study, we assessed whether at a heterogeneous site, non‐experimental GUDs could reveal the effect of disturbance. We measured initial and GUDs of tubers of Fennel Pondweed Potamogeton pectinatus, which form here the exclusive food source of Bewick's Swans Cygnus columbianus bewickii during their migratory stopover. We calculated giving‐up net energy intake rates (GUNs) by correcting for biomass accessibility and foraging costs. The study area was a shallow lake consisting of nine creeks, three of which were open to the public (i.e. disturbed). GUDs in creeks open or closed to the public were not significantly different. In contrast, GUNs were generally higher in creeks open to the public, after correcting for initial net energy intake rate. The results suggest that natural GUDs may not reflect the effects of disturbance in heterogeneous habitats. When environmental differences are large within a site, GUNs may be a useful alternative as a behavioural indicator.  相似文献   
6.
L. Gao  Q. Wei  F. Fu 《Plant biosystems》2013,147(4):1175-1183
Macroalgal blooms have occurred worldwide frequently in coastal areas in recent decades, which dramatically modify phosphorus (P) cycle in water column and the sediments. Rongcheng Swan Lake Wetland, a coastal wetland in China, is suffering from extensive macroalgal blooms. In order to verify the influence of macroalgal growth on sediment P release, the sediments and filamentous Chaetomorpha spp. were incubated in the laboratory to investigate the changes of water quality parameters, P levels in overlying water, and sediments during the growth period. In addition, algal biomass and tissue P concentration were determined. In general, Chaetomorpha biomasses were much higher in high P treatments than in low P treatments. Compared with algae+low P water treatment, the addition of sediments increased the algal growth rate and P accumulation amount. During the algal growth, water pH increased greatly, which showed significant correlation with algal biomass in treatments with high P (P < 0.05). P fractions in the sediments showed that Fe/Al–P and organic P concentrations declined during the algal growth, and great changes were observed in algae+low P water+sediment treatment for both. As a whole, the sediments can supply P for Chaetomorpha growth when water P level was low, and the probable mechanism was the release of Fe/Al–P at high pH condition induced by intensive Chaetomorpha blooms.  相似文献   
7.
Following increases in numbers during the second half of the 20th century, several Arctic‐breeding migrant bird species are now undergoing sustained population declines. These include the northwest European population of Bewick's Swan Cygnus columbianus bewickii, which declined from c. 29 000 birds on the wintering grounds in 1995 to 18 000 in 2010. It is unclear whether this decrease reflects reduced survival, emigration to a different area, or a combination of both. Furthermore, the environmental drivers of any demographic changes are also unknown. We therefore used an information‐theoretic approach in RMark to analyse a dataset of 3929 individually marked and resighted Bewick's Swans to assess temporal trends and drivers of survival between the winters of 1970/71 and 2014/2015, while accounting for effects of age, sex and different marker types. The temporal trend in apparent survival rates over our study period was best explained by different survival rates for each decade, with geometric mean survival rates highest in the 1980s (leg‐ring marked birds = 0.853, 95% confidence interval (CI) 0.830–0.873) and lowest in the 2010s (leg‐ring = 0.773, 95% CI 0.738–0.805; neck‐collar = 0.725, 95% CI 0.681–0.764). Mean (±95% CI) resighting probabilities over the study period were higher for birds marked with neck‐collars (0.91 ± 0.01) than for those marked with leg‐rings (0.70 ± 0.02). Weather conditions in different areas across the flyway, food resources on the winter grounds, density‐dependence and the growth of numbers at a relatively new wintering site (the Evros Delta in Greece) all performed poorly as explanatory variables of apparent survival. None of our 18 covariates accounted for more than 7.2% of the deviance associated with our survival models, with a mean of only 2.2% of deviance explained. Our results provide long‐term demographic information needed to help conservationists understand the population dynamics of Bewick's Swans in northwest Europe.  相似文献   
8.
环境温度变化通过影响鸟类的行为进而使其活动区也发生变化,探讨三者之间的关联性有助于理解鸟类是如何通过行为调整以适应周围环境的变化,来满足自身的生理需求。本研究通过卫星跟踪的方法获得了在河南三门峡湿地越冬的31只大天鹅(Cygnus cygnus)详细位点数据,在ArcGIS和R语言中采用核密度估计法计算大天鹅的活动区面积,在SPSS中采用Spearman分析平均温度与活动区面积的相关性;并利用瞬时扫描法获得大天鹅越冬行为观察数据,采用非参数Kruskal Wallis检验对大天鹅行为的差异性进行分析,探讨了环境温度与大天鹅越冬行为和活动区三者之间相互作用的模式。研究表明,从越冬初期至后期,随着环境温度的先下降后升高,大天鹅的取食、运动、静息等主要行为发生了较大的变化,静息和取食行为先增加后减少,运动行为则先减少后增加。越冬不同时期的核心区和活动区面积与温度呈显著性正相关。大天鹅在不同时段的活动区面积大小整体上均呈现出先减少后增加的趋势。随着环境温度的变化,大天鹅的越冬行为也随之发生了调整,进而使活动区面积发生改变,主要体现在越冬初期大天鹅通过增加活动区面积及时补充能量增加体能,越冬中期减少活动保持能量需求,越冬后期增加盘旋飞行使得活动区面积增大等。大天鹅这一系列行为和活动区的调整都是为了更好地满足越冬不同时期的生理需求。  相似文献   
9.
湖北天鹅洲故道江豚的活动与行为   总被引:11,自引:3,他引:8  
本文对湖北天鹅洲故道中捕自长江的6头江豚(NeophocaenaphocaenoidesCuvier)之活动及行为进行了较为详细地研究,描述和分析了江豚的群体家域、活动能力、活动在各研究区的季节性变化及其与豚活动相关的一些环境因素和豚的一些行为。不但为保护和管理这种国家二类保护动物提供理论依据;更重要的是,为在此故道建设的白豚(LipotesvexilliferMiller)自然保护区作了进一步的生态评价,并提出了合理的建议。  相似文献   
10.
The role of aquatic macrophytes in stimulating biodiversity and maintaining clear waters is currently undisputed. The management of (eutrophic) shallow waters is therefore often directed at (re-)establishing macrophyte domination. In contrast, the role of water birds has long been considered of minor importance for the functioning of fresh water ecosystems. Indeed, in terms of biomass and production, water birds constitute only a minor part of these systems. However, water birds may graze heavily on water plants under certain circumstances, and the question arises whether herbivorous water birds have an important indirect effect on shallow fresh water systems. Mainly illustrated with the interaction between Bewick’s Swans and Fennel Pondweed, we present data on the role that water plants may play in the life of water birds and how water birds may impact water plants’ fitness in terms of survival, production, dispersal and competitive ability. It appears that water plants may be crucial for water birds during periods of high-energy requirements, such as migration. Despite the plants’ costs associated with water bird grazing, the interaction between water birds and water plants varies in nature from an apparent predator–prey relationship to a mutually beneficial interaction depending on the context and the perspective. For the case of the Bewick’s Swan–Fennel Pondweed interaction, regular bird grazing is sustainable and may actually favour the plant’s dispersal. Thus, Bewick’s Swans themselves may in fact play a crucial role in establishing and maintaining the Fennel Pondweed rich staging sites between the swans’ wintering and breeding grounds, which are vital for the swans’ successful migration.  相似文献   
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