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1.
During the second half of August 1992 polar bears were observed feeding intensively in the little auk Alle alle colony on Rubini Rock, Hooker Island, Frans Josef Land. They dug out nests eating eggs, chicks and adult birds. Their activity results in both worsening the breeding conditions and decreasing the breeding success of the little auks. The polar bear has not earlier been known as a little auk predator.  相似文献   

2.
Breeding biology, nestling growth and development, and biometry of the little auk Alle alle polaris were studied in Franz Josef Land. A total of 103 adult birds were measured, 60 in the field and 43 in the St. Petersburg Museum. The development of 16 chicks was compared with that of Alle a. alle chicks from Spitsbergen. At particular stages of development, both adults and nestlings of A. a. polaris are larger than those of A. a. alle .
In Franz Josef Land the breeding season is more extended and less synchronised than that of Svalbard. The majority of the little auks in the studied colonies in Franz Josef Land nested on steep rocky cliffs, possibly as an adaptation to the severe climatic conditions and heavy mammalian predation in subcolonies located on accessible mountain slopes. Glaucous gulls Larus hyperboreus exerted negligible predatory pressure. This study confirms the existence of morphologically distinguishable populations of the little auk on Franz Josef Land and Svalbard, supported by recent studies of climatic and oceanographic conditions in the two areas that parallel the morphological differentiation.  相似文献   

3.
食草动物处理和消耗食物受单位时间内饲料质量和数量有效性的不同影响。异速反应理论被认为是食草动物觅食栖息地选择的重要决定因素,并已经被广泛应用于不同体型的食草动物研究。但其在解释不同消化生理和体型的食草动物如何利用生境斑块方面尚不明确。本研究通过整合河马(河马科,大型非反刍动物)和牛(反刍动物)的觅食关系,揭示了不同消化生理和体型的食草动物对生境斑块的应用。整个雨季和旱季,通过在加纳的Bui国家公园布设的48块100 m×100 m的样方来分析物种密度降低与环境变量之间的显著关系。结果表明,雨季河马和牛更倾向于利用靠近河流的区域,但河马在旱季会选择远离河流的地区觅食。草地的高度也决定了这两个物种对草地的利用,河马选择使用更矮的草地。分析食物的质量可知,食物氮含量对反刍动物(牛)的斑块选择有显著影响。然而,酸性清洁纤维含量则与非反刍动物(河马)呈正相关。在Bui国家公园,草地高度和食物质量对斑块使用的高季节性影响主要是由河马和牛的消化生理和体型不同所决定。  相似文献   

4.
In 1988, first-year Herring Clupea harengus were the dominant prey fed to Puffin chicks on Hernyken, Røst. Puffins carrying food loads were observed at least 137 km from the colonies in July. In early August, two major feeding areas were located about 20 and 85-105 km off Røst. These long foraging ranges and an insufficient availability of food are thought to be the main reasons for the poor chick growth this year. No relationships were found between the distribution of Puffins observed at sea and survey station data on prey distribution, sea temperature or salinity, but this may have been due to inadequate sampling of these parameters. A recorded seasonal change in flight direction of adults returning to colony is discussed in relation to food quality and chick growth.  相似文献   

5.
王自磐 《极地研究》2002,14(2):83-92
对南极长城站和中山站两地的贼鸥种群进行包括营巢行为、觅食习性、种群变化、繁殖生态 ,以及贼鸥栖息地的地理和生态环境等的比较研究 ,结果表明两地贼鸥种群存在明显的生态学差异。这种差异不仅反映了贼鸥的生态习性与栖息地自然环境和生态结构的密切相关性 ,更体现了该种海鸟对南极不同生存环境极强的适应能力。人类活动以及贼鸥对人类废弃食物的依赖 ,在一定程度上改变动物食物结构 ,并对贼鸥生态习性乃至种群数量变化均产生一定影响。两地贼鸥种群通过改变觅食对策和调整产卵、孵化时间和延长育雏期等 ,达到对不同地理纬度和气候条件的适应 ,确保物种的延续  相似文献   

6.
In 1984, kittiwakes at Hopen laid eggs ca. 14 days later than previously found in North Norway and on the Kola Peninsula. The mean clutch size, egg volume, and hatching success were otherwise very similar to those documented on the mainland. Although feeding trips were very long, a rapid chick growth and high rate of chick survival suggested that food availability was not a limiting factor in 1984. In contrast to other sites at Svalbard where polar cod Boreogadus saida and crustaceans dominate kittiwake diets, the diets of chicks at Hopen consisted mainly of capelin Mallotus villosus which the adults probably collected at or beyond the polar front southeast of the island.  相似文献   

7.
This year is a kind of anniversary for the Norwegian Polar Institute: its establishment can be traced back to Svalbard expeditions sponsored by Prince Albert I of Monaco in 1906 and 1907. In this unreviewed biographical article, biologist Eva Fuglei, who has spent many seasons on Spitsbergen (where her research has focused on Arctic foxes), and the editor describe part of the uncommon life of botanist Hanna Marie Resvoll-Holmsen, who participated in the 1907 expedition.  相似文献   

8.
北京航空旅客出行特征及新机场旅客分担   总被引:1,自引:0,他引:1  
本文基于北京市大样本航空旅客问卷调查, 采用结构相似系数和序数逻辑回归模型对398 份普通旅客问卷和3942 份航空旅客问卷定量分析发现:北京地区的旅客出行具有“近谷远峰”的空间性, 其对交通方式的选择具有“航进陆退”的发展趋势和“近汽远飞”的空间特征;基于票价、时间、舒适和自由等4 大因素, 旅客按照供需结构相似决策机制, 选择出行交通方式;年龄和性别对航空旅客出行的影响不显著, 教育程度和月收入水平对航空旅客的“时间价值”、“乘机比例”和“乘机频率”均有正向影响, 其中月收入水平影响最大;公商务旅客主要选择飞机和动车出行, 度假旅游者主要选择动车和飞机出行, 探亲访友者主要选择长途汽车和自驾车出行, 学生主要选择火车和长途汽车出行。基于时间价值和效用函数, 采用logit 模型计算出北京新机场对北京市航空旅客的分担率为41.2%。  相似文献   

9.
福建省县域可持续发展水平空间格局与动态变化研究   总被引:2,自引:0,他引:2  
通过构建福建省县域可持续发展水平的评价指标体系并收集相关数据,采用主成分分析、方差分析与加权移动平均等方法对2003-2008年福建省县域可持续发展水平空间格局与动态变化进行分析。结果表明:1)福建省县域可持续发展水平整体两极分化明显,且两级差距扩大;高发展水平的县域间差异显著,而低发展水平的县域间差异不明显。2)福建省可持续发展空间格局由"沿海一级长轴"、"西部二级短轴"及广大低水平区域构成。"沿海一级长轴"范围稳定,等级结构优化;"西部二级短轴"范围变小,等级稳定,可持续发展水平空间不平衡有所减弱。3)在海峡西岸经济区建设过程中,应基于福建省可持续发展水平和空间特征,促进闽台多层次和全方位的分工与合作。  相似文献   

10.
The practice of gathering and harvesting wild foods has seen renewed interest in recent decades. In addition to contributing to food security and food sovereignty, foraging plays a role in promoting socioecological resilience and creating communities of belonging. However, foraging is generally prohibited by regulations governing public lands in the United States and elsewhere. The growth in food forests suggests public policymakers and land managers’ may be interested in reconsidering this broad prohibition of foraging but require an information base to do so. While a body of research on foraging exists, news media coverage of foraging represents an additional, readily available source of input. As a consequence, framings of foraging in media coverage likely influence managers’ deliberations on this practice. The current paper uses automated content analysis to understand how the practice of gathering and consuming wild foods is framed in print and digital news media, and how these depictions have varied in a 15-year period that includes the Great Recession. Our results show that prevalent framings of foraging represent it variously as a self-provisioning practice or a source of luxury commodities and experiences, with economic uncertainty appearing to affect the frequency of each framing by news media sources. Given managers’ ease of access to them, these distinct framings may influence future regulatory landscapes of foraging.  相似文献   

11.
In combination with observations in spring staging and wintering grounds in western Europe, a detailed etho-ecological study of nesting dark-bellied brent geese Branta b. bernicla in western Taimyr, Krasnoyarsk, Russia, was made in 1990. Most brent geese arrived on the breeding grounds from 14–19 June and started nesting within a few days. In the study area 264 nests of breeding brent geese were found, mainly on islands but also along small rivers on the mainland. The mean clutch size was 3.0 and 80% of the eggs hatched. Time budget studies showed that incubating females spent on average 138 minutes per 24 hours on feeding. Despite favourable weather conditions and a low density of arctic foxes, only about one-third of the mature birds in the study area bred. In the autumn an intermediate breeding success of 20% juveniles was recorded in the wintering areas. This was probably due to the relatively poor condition in which the brent geese left their spring staging areas.  相似文献   

12.
Metabolic rates and Q10 values were determined for three species of Spitsbergen Coleoptera, Amara quenseli, Simplocaria metallica and Rhynchaenus flagellum . The beetles had metabolic rates which were elevated compared to values of Coleoptera from other regions. This is interpreted as an adaptation to the prevailing low temperatures and short activity period on Spitsbergen.
A. quenseli had rates of water loss comparable to values of beetles in temperate and tropical xeric habitats, indicating that the habitat of the beetles on Spitsbergen at least occasionally is xeric.
Determination of cold-hardiness parameters such as supercooling point and haemolymph melting point of A. quenseli beetles revealed that the beetles had values corresponding to those of active insects in the temperate and tropical region. They had no thermal hysteresis factors. Thus, during summer they show no physiological adaptations to cold.  相似文献   

13.
Time budgets and activity patterns of sandgrouse were studied in semi-arid agricultural land in Spain (Black-bellied and Pin-tailed Sandgrouse) and in more desertic conditions in Israel (Black-bellied and Spotted Sandgrouse). During c. 75% of daylight hours, all four species were either foraging or inactive. The birds in Israel spent more time foraging than those in Spain, despite having lower thermoregulatory costs, reflecting a likely difference in the productivity of the sites. Partitioning of foraging habitat was evident at both sites and, contrary to expectation, it was the larger Black-bellied Sandgrouse which spent the most time foraging. In Israel, Spotted Sandgrouse became inactive at high temperatures whereas the Black-bellied continued to forage, utilizing the shade available in its dwarf shrub foraging habitat. The range of Black-bellied Sandgrouse may be limited by its thermoregulatory ability in hot conditions and its need to forage for long periods.  相似文献   

14.
Skuamounds are peaty hillocks up to 70 cm high used by Arctic Skuas (Stercorarius parasiticus (L.)) for surveying their breeding territory. Well-developed skua-mounds in Svalbard can be considered as small guanogenic bogs', because the peat formation depends on manuring by birds and the water-table in the mound is higher than the surrounding tundra. Peat sections measuring 34 cm and 40 cm from two skuamounds from Edgeøya and Spitsbergen were radiocarbon dated and studied for pollen and spores. Peat formation on the two skua-mounds started c. 4500 calendar years ago. Concentration values of longdistance transported pollen were used to detect time gaps in the records. The time gap in the skua-mound from Spitsbergen was found to be considerably greater than in the skuamound from Edgeøya. Erosion has progressed considerably further on the Edgeøya skua-mound than on the skua-mound from Spitsbergen due to differences in hydrology: the peat of the former mound is dry and unfrozen in summer, whereas in the latter mound it is wet and frozen. Time gaps and erosion are probably associated with phases of decreased manuring by birds. At two levels in the Edgeøya skua-mound there is evidence of a climatic change towards cooler conditions, one being an early major climatic shift and the other a later minor climatic shift. A similar major climatic shift is associated with one level in the skuamound from Spitsbergen.  相似文献   

15.
Ants of the speciesMessor arenariusandM. ebeninusare known as common granivores in the deserts of the Middle East and North Africa. The relationship between the spatial distribution of nests of these ant species and the distribution of vegetation was examined in the Negev highlands. Using the method of nearest neighbour analysis, it was found that nests ofM. arenariusare evenly dispersed while the dispersion of nests ofM. ebeninusdoes not differ from a random distribution. It is suggested that in desert surroundings there is a connection between the distribution pattern of nests of harvester ants and their foraging type. It seems that nests of individually foraging ants are usually evenly dispersed while nests of trunk-trail foraging ants are usually distributed in a random or aggregated dispersion.  相似文献   

16.
Aristoptychites kolymensis (Kiparisova) is investigated and described in detail from collections made at Botneheia, Spitsbergen, where it occurs at the top of the Botneheia Formation (Daonella Shale). It is a rather small species and the stratigraphically highest representative of the genus in Spitsbergen. Its suture line is remarkable by its possession of the additional U.-lobes between the internal lobe and the first umbilical lobe. A lobe of this kind has so far been described only once, with Arcestes (Proarcestes) bicarinatus by Schindewolf (1968), which suggests affinities between Ptychitidae and Arcestidae.  相似文献   

17.
The proportion of individuals age sixty-five and over is growing at an astronomical rate in the United States, and some estimate that this demographic age group will double by the year 2025. Older adults and adults nearing retirement age tend to reside in suburban neighborhoods and rely heavily on personal vehicles. This study uses travel diary data on automobile trips to construct activity spaces to explore whether or not travel patterns across age groups result in differential access to particular goods and services in the Orlando Metropolitan Statistical Area (MSA). Using an approach based on time geographic density estimation, this research identifies activity spaces across different age cohorts to identify differences in the automobility of different age groups. Results indicate that the geographic dispersion of activities with the Orlando MSA currently favors younger adults. Adults age fifty to sixty-four had the lowest accessibility scores compared to other age cohorts. If this preretirement group has poor access now, holding other effects constant, their access might only get worse as they get older and stop commuting. Transportation is an important consideration in planning for aging populations, and analyzing differences in how older adults travel compared to their younger counterparts can offer insight into the diverse needs of this group. Key Words: accessibility, aging populations, mobility, time geography, transportation.  相似文献   

18.
Analysis of benthic foraminiferal assemblages was performed in Bathonian to Kimmeridgian deposits through a section covering the lower half of the Agardhfjellet Formation in central Spitsbergen. The section consists mainly of organic-rich shales, which contain low-diversity agglutinated assemblages. In this foraminiferal succession five morphogroups were differentiated according to shell architecture (general shape, mode of coiling and number of chambers), integrated with the supposed microhabitat (epifaunal, shallow infaunal and deep infaunal) and feeding strategy (suspension-feeder, herbivore, bacterivore, etc.). The environmental evolution of the analysed section is interpreted by using the stratigraphic distribution of morphogroups, combined with species diversities and sedimentary data, in a sequence stratigraphic framework. The section comprises two depositional sequences, which demonstrate that species diversity and relative frequency of morphogroups are correlative with transgressive–regressive trends controlling depth and oxygenation of the water column. In both sequences, the maximum flooding interval is characterized by increased organic carbon content, dominance of the epifaunal morphogroups and reduced species diversity: features reflecting the increased degree of stagnation separating the transgressive phase from the regressive phase.  相似文献   

19.
蒙古野驴(Equus hemionus)昼间行为时间分配初探   总被引:1,自引:0,他引:1  
于2007 年和2010 年采用焦点动物取样法研究了新疆卡拉麦里山有蹄类野生动物保护区蒙古野驴昼间行为时间分配和活动节律,共采集行为数据460 h,观察蒙古野驴2 760 头次,将蒙古野驴昼间行为分为采食、移动、警戒、休息和“其他”5 类。采用卡方检验分析不同季节各种行为时间分配,结果表明:季节因素对蒙古野驴行为时间分配存在极显著影响(χ2=79.06,df=12,P<0.01)。采用ANOVA分析同季节不同行为间差异,结果表明,春季:移动、警戒、“其他”两两间无显著差异([WTBX]P>0.05),其余两两间差异显著(P<0.05);夏季:仅移动与“其他”间无显著差异(P>0.05);秋冬季:仅警戒与“其他”间无显著差异(P>0.05)。对蒙古野驴昼间活动节律研究结果表明,蒙古野驴采食时间比例在春季各时段均较高(>45%),仅中午(14:00~15:00)有1个低谷(27.62%),夏秋季则为晨昏采食模式,冬季采食峰值(87.85%)在中午时段(13:00~14:00)。休息和采食高峰在各季节交叉出现,呈现此消彼长的趋势。各季节移动主要发生在晨昏时段。蒙古野驴以特定的行为时间分配模式和活动节律适应环境条件季节性变化,如气候条件、食物资源、人为干扰、生理期、昼间长度、捕食风险等。  相似文献   

20.
This study investigates whether women's short commutes should be interpreted as constrained or convenient work trips by examining how race, gender, travel mode, occupation, residential location, workplace location, and Inc.ome affect commuting time. The analysis is restricted to a sample of European American and African American male and female workers residing in Buffalo, New York, and the surrounding county using data drawn from the Public Use Microdata Samples of the 1990 U.S. census. Given the pervasive gender wage gap, women unsurprisingly have more compromised (short commutes to low-Inc.ome jobs) work trips than do men. Multivariate analysis reveals that among those who reverse commute to suburban locations, African American women have the longest work trips.  相似文献   

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