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 770 毫秒
1.
Quantitative data of winter bird censuses in forest habitats of the Ilmen Nature Reserve (1986–2010) have been analyzed with regard to changes in the monthly average, maximum, and minimum temperatures and precipitation in the period from December to February. No warming trend has been revealed in the reserve over the study period, The dynamics of bird population structure in winter has proved to be independent of weather conditions, despite significant interannual fluctuations. The most significant factors of long-term dynamics of abundance of wintering birds include population density in the previous nesting period, the seed yield of the main food plants, and local migration of wintering species.  相似文献   

2.
升金湖湿地是安徽省内的唯一以越冬鹤类为保护对象的国家级自然保护区。研究湿地景观格局变化对越冬鹤类地理分布的影响在恢复湿地生态系统、保护鹤类种群等方面具有重要参考价值。该文对升金湖湿地的白头鹤、白鹤、灰鹤及白枕鹤越冬鹤类的地理分布特征进行了分析,结合升金湖湿地1986~2017年间的8期遥感影像分析景观格局变化特征,并探讨了景观格局变化对越冬鹤类地理分布特征的影响。结果表明:1986~2017年间,升金湖湿地景观格局变化显著,斑块数量增加,景观破碎化严重。泥滩地、草滩地、建设用地、水田面积总体呈增加态势,旱地、林地、芦苇滩地及水域面积总体呈减少态势;4种鹤类数量总体呈减少趋势。鹤类主要地理分布区域为水域、水田、芦苇滩地、泥滩地及草滩地;升金湖湿地景观破碎化不断加剧,鹤类地理分布区域面积整体上在逐渐减少,适宜鹤类生境面积减少,直接导致近30年来鹤类数量逐渐减少。  相似文献   

3.
The Macrolepidoptera fauna of the Urals, from the southern to the northern boundary of the forest zone (i.e., from the forest–steppe of the Southern Urals to the forest–tundra of the Polar Urals) has been analyzed. It has been demonstrated that the proportion of Lepidoptera feeding on woody plants, including evergreens, increases in this direction. Among the Heterocera, the proportion of species feeding on graminoids decreases; in the Polar Urals, none of these species is specialized. The food spectrum is particularly variable in noctuids and almost invariable in geometrids and Rhopalocera. It is assumed that foods with a low nutrient value (grasses, mosses, lichens, plant debris, wood, and roots of various plants) prevent Macrolepidoptera species from spreading in the Subarctic region. In the Polar Urals, multiyear developmental cycles and wintering at the larval stage are related to feeding on these types of food.  相似文献   

4.
升金湖自然湿地越冬鹤类生境适宜性变化研究   总被引:2,自引:0,他引:2  
升金湖湿地位于安徽省长江中下游区域,是鹤类重要的越冬地之一,湿地景观的变化影响越冬鹤类的生境质量。研究湿地内越冬鹤类生境变化地对湿地生态恢复有着重要的研究意义。以升金湖国家级自然保护区为研究对象,利用ERDAS软件将1986年到2015年间8个年份冬季的TM影像数据将景观类型分为8种类型,用FRAGSTATS软件计算出各个年份的景观指标。选取干扰程度、食物丰富度、植被覆盖和水文条件4种因子作为影响越冬鹤类生境的主要因子。建立越冬鹤类生境适宜性评价模型,用ArcGIS生成鹤类生境适宜性评价图。用皮尔逊相关分析研究鹤类数量与生境适宜性的相关性。结果表明:升金湖保护区的景观格局变化明显,湿地斑块数量增加,景观的破碎度程度增加,景观斑块差异在逐渐变小,多样性指数和均匀度指数逐渐变大。越冬鹤类生境适宜性综合指数从0.845下降到0.465,总体的生境明显恶化。越冬鹤类的生境适宜性面积从1986年的 13 577.11 hm2 下降到2015年的 7 424.42 hm2,进而导致越冬鹤类数量在1986年到2015年总体呈下降趋势。鹤类数量与生境适宜性呈正相关。 关键词: 生境影响因子;生境适宜性评价模;越冬鹤类;景观格局  相似文献   

5.
The impact of succession stage on the share of clonal plants in the plant cover, seed rain and seedling pool has been studied in the years 2014 and 2015. The investigations were carried out in abandoned Molinion caeruleae meadows dominated by small-statured species (Patch I), tall growing large-tussock grasses (Patch II) and shrub-willows (Patch III). Although the clonal taxa dominated in the plant cover, seed rain and seedling pool, their share in subsequent study sites was quite different. The spectra of life-history traits relevant to clonality in the plant cover and seed rain were similar and did not vary significantly among subsequent locations, while they mostly differed as observed in the seedling pool. The various spectra observed in seedling pool in subsequent study sites might be due to fact that the seed germination and recruitment of offspring are strongly influenced by habitat conditions which varied remarkably in the successive Patches.  相似文献   

6.
Trends in adaptation to new habitats of orphaned bear cubs in the period of rearing and after release into the wild have been revealed. The pattern of their distribution in a biotope is contingent on its exploration in search for food, with the intensity and scale of this process increasing as the animals grow. The results indicate that the methods of rearing used in the Ussuri Nature Reserve are effective and promising.  相似文献   

7.
A mechanism of the formation of biological rhythms in hibernators at cold temperatures is proposed. Certain ecophysiological characteristics have been studied in three hibernating species: the ground squirrels Citellus undulatus Pallas, 1778 and C. parryi Richardson, 1825 and the chipmunk Tamias sibiricus Laxmann, 1769. The changes in body temperature and the temperature of litter in wintering nests during hibernation seasons have been studied. The dependences of metabolic rate on ambient temperature and the size and species of animals have been studied.  相似文献   

8.
In Yakutia, the brown bear inhabits the forest and forest-tundra zones. Compared to bears from other regions of Russia, Yakutian bears have slightly smaller body and skull sizes and are mainly herbivorous, with their wood spectrum being relatively narrow. Their fecundity averages 1.68 cubs per parous female. The bears make their dens at a depth reaching 2.5–3 m. The denning period begins early and is 195–210 days long. An electroencephalographic analysis of the effect of a 1–10 kDa peptide fraction from the bear brain on Wistar rats has shown that wintering bears are in the state of sleep, or “superficial hibernation.”  相似文献   

9.
Average and summary values of five paired meristic characters of the head seismosensory system have been estimated in roach from 11 ponds and medium-size reservoirs in Udmurtia. It has been found that the level of fluctuation variance in the summary character values is significantly correlated with the values of water mineralization and total dry solids in the water bodies, and the average summary values, with the absolute and relative contents of magnesium ions in the water. A possible role of magnesium in determining the quantitative indices of seismosensory characters, which are formed during early fish ontogeny, is discussed with regard to the results of a pilot laboratory experiment on rearing roach juveniles under different hydrochemical conditions.  相似文献   

10.
The results of regression and correlation analyses of long-term data (1971–2005) on the dates of arrival of 16 bird species to the Il’men State Nature Reserve (the Southern Urals) show that they have not changed in most of these birds, unlike in many countries of Europe and North America. This is explained primarily by the absence of any significant trends in the dynamics of spring air temperatures in the study region. Only the herring gull Larus argentatus and the lapwing Vanellus vanellus have shown a significant tendency to arrive earlier, while the garganey Anas querquedula has shown a tendency to arrive on later dates in the past two decades. Nevertheless, interannual fluctuations in the dates of arrival are well manifested in both early arriving species wintering in Europe and late-arriving species wintering in Africa. These fluctuations largely depend on temperature conditions in spring. As a rule, almost all species studied—from waterbirds to passerines—appear in the Il’men Reserve earlier in years with early and warm springs than in cold years. Hence, spring weather is the key factor determining the dates of arrival of migratory birds to the study region.  相似文献   

11.
上海浦东东滩鸟类栖息地生态修复区的水鸟群落变化   总被引:1,自引:0,他引:1  
河口和海岸带自然湿地的大量退化与丧失导致了迁徙路线上水鸟栖息地的大量减少,从而加剧了迁徙水鸟种群数量的下降,一般认为,栖息地修复能够缓解上述过程。于2010年、2012年对位于上海浦东东滩的鸟类栖息地生态修复区和自然退化区(对照样地)进行调查,比较两个区域的水鸟群落结构差异与年际变化,研究生态修复区的水鸟群落变化并评价其在水鸟保育方面的作用。结果表明:生态修复区的水鸟种类、数量和物种多样性均极显著高于自然退化区,而均匀度与自然退化区无显著差异;生态修复区2012年水鸟种类显著低于2010年,而水鸟数量、物种多样性和均匀度均无显著差异;自然退化区2012年水鸟种类、数量和物种多样性均极显著低于2010年,而均匀度无显著差异。生态修复区通过营造浅滩、浅水区、深水区等多样化生境,为迁徙水鸟提供了重要的补充栖息地,对水鸟保育工作起到了积极作用  相似文献   

12.
目前为止缺少对鄱阳湖全湖冬候鸟的种群动态和群落方面的研究分析,拟通过对鄱阳湖冬候鸟群落多样性和种群动态的分析,为该地区冬候鸟及其栖息地保护提出建设性建议。2010~2012年冬季,通过采用直接计数法和样线法调查鄱阳湖湿地冬季碟形湖内的越冬鸟类群落结构。总共记录到越冬鸟类88种,另有29种属于文献报道但本次调查中未发现的种类。总共117种鸟类分别属于目、鹈形目、鹳形目、雁形目、鹤形目、鸻行目和佛法僧目。在鄱阳湖,种类和数量分布最多的是冬候鸟,达到78种。小天鹅、鸿雁、豆雁、白额雁、绿翅鸭和斑嘴鸭是鄱阳湖湿地越冬鸟类中的绝对优势种,鸟类个体数量最多的冬季蝶形湖泊主要包括鄱阳湖自然保护区的蚌湖、大湖池、沙湖和大汊湖,都昌县的黄金嘴,南矶山湿地自然保护区的白沙湖,余干县的林充湖和南湖,以及鄱阳县的珠湖。各种越冬鸟类在鄱阳湖湿地的种群数量分布差异主要是与各碟形湖水位的高低和食物的分布密切相关。只有在冬季开始后,使碟形湖洼地的水位逐渐降低,越冬鸟类才能够更有效的利用湖泊中的食物  相似文献   

13.
The effect of rise in spring air temperature on the breeding phenology and reproductive success of the Song Thrush in the Voronezh Nature Reserve have been studied over the periods of 1987 to 1990 and 2008 to 2012. The results show that relatively high air temperatures provide for earlier arrival of the birds from wintering grounds, earlier and more synchronous breeding of the majority of nesting pairs, and an increase in clutch size and proportion of pairs producing two broods per season. Predation pressure on bird nests decreases under such conditions, which markedly improves reproductive success. Climate warming is conducive to increasing breeding productivity of the Song Thrush population as a whole.  相似文献   

14.
丹江口水库对汉江中下游影响的生态学分析   总被引:1,自引:0,他引:1  
基于黄家港水文站1954~2000年的日径流量资料,以1967年为节点,将47年水文序列划分为节点前的“近自然状态河流”和节点后的“人工干扰状态河流”两种水文情势。采用Richter提出的变动范围法,基于包含32个水文参数的水文改变指标体系,定量评估了黄家港水文站1967年前后水文情势的变化。根据分析,把1967年之前的各个水文参数的第1至第3四分位数间的数值范围设为管理目标。进一步分析了丹江口水库的修建对汉江中下游生态水文的影响。结果表明,1967年以后,丹江口水库的修建对汉江中下游水文情势的影响较为显著:极大地改变了径流的年内分配,使流量过程均化,使极值流量出现日期提前、历时缩短等等。在此基础上,结合汉江中下游河道生态系统的特点,以鱼类为指示生物,初步探讨了上述水文情势的变化对汉江中下游鱼类的生长、繁殖和越冬等带来的影响,并对如何降低不利影响提出了相应的改进措施.  相似文献   

15.
1996~ 1998年 ,在北纬 30°15′~ 30°30′ ,东经 115°5 5′~ 117°15′之间的中国安徽升金湖 ,我们对来此越冬的白头鹤 (Grusmanacha)进行了越冬期环境容纳量研究 ,结果表明 :白头鹤在升金湖上湖越冬期的主要食物苦草及蚌类的储藏量 ,经初步测算两者共有 5 9.2t ,折算能量分别为 1.5 11×10 8kJ与 1.6 95× 10 8kJ ,折算总能量为 3.170× 10 8kJ按每只白头鹤在升金湖越冬期为 145d ,越冬期日粮为 6 95 g ,折算消耗能量72 2 1.7kJ计算 ,上湖可容纳白头鹤种群数量的理论值是 30 2只。同时 ,环境因子的变化 ,如降水量、湿度及人为活动是影响白头鹤在升金湖越冬种群数量发生变动的主要原因。控制人为活动 ,保护适合的水位是稳定白头鹤越冬种群的主要措施  相似文献   

16.
The effect of rearing conditions for gypsy moth larvae on parameters of their development (its duration and mortality) was studied in experiments with early instar larvae reared singly or in groups. The manifestation of the group effect was analyzed depending on the choice of experimental unit (the larva or the rearing container) and the amount of volume per larva. The observed effects were evaluated quantitatively.  相似文献   

17.
Analysis of the seasonal dynamics of body weight and steroid hormones (cortisol, progesterone, and testosterone), the pattern of hypothermia, and basic reproductive parameters has been performed in the Mongolian hamster (Allocricetulus curtatus), a poorly studied rodent species inhabiting areas with a sharply continental climate. The results show that torpor bouts take place in wintering animals. Changes in body weight during the autumn-winter season are insignificant. The pattern of fluctuations in the levels of sex steroids and cortisol is similar to that in dwarf hamsters of the genus Phodopus. Seasonal features in the dynamics of basal cortisol level differentiate A. curtatus from the closely related Eversmann’s hamster (A. eversmanni), which may be due to differences in the social structure of these species.  相似文献   

18.
The correlation between the timing of adult emergence and variation in morphophysiological parameters of males and females has been analyzed in the black-veined white Aporia crataegi L. In 2013 to 2015, black-veined white butterflies were collected from a natural population in the south of Sverdlovsk oblast throughout the emergence period; at the same time, adult insects were reared from pupae in individual cages. Comparison of the field observations in nature and the results of rearing preimaginal stages has shown that the largest adults are the first to emerge, while the smallest are the last to emerge. This pattern holds true both for the parameters varying throughout the adult insect life (body weight and relative abdomen weight) and for the permanent characteristic of the “structural” size (wing area). The influence of protandry and food availability to caterpillars on the variation in the size of adult A. crataegi during the period of generation emergence is discussed.  相似文献   

19.
The body size structure of carabid communities has been analyzed based on the 2009 and 2013 collections (with the use of pitfall traps) performed at 10 sites of a spruce–fir forest along the gradient of pollution with emissions from the Middle Ural Copper Smelter. A reduction in the unweighted mean body size of carabid individuals has been shown, as well as the heterogeneity of body sizes in the community (Gini coefficient) of the extremely polluted territory. It has been revealed that the weighted mean body size of individuals and the Lorentz asymmetry coefficient are not dependent on the level of pollution. Differences between the communities of carabids in the background and polluted territories are associated with the smaller number of large-sized species, while the similarity is explained by the dominance of medium- and small-sized species at all sites. The high interannual variability has been observed in the ratio of size groups of the analyzed communities at the background and moderate levels of pollution.  相似文献   

20.
Anthropogenically derived 14C has been used to trace recent carbon input in a study of carbon accumulation and turnover in Canadian soils. In order to do so, documentation of the undisturbed nature of the soil horizons sampled was of prime concern. Although all the sites chosen for coring were currently uncultivated, detailed information on long-term land usage was not available. To overcome this problem, 137Cs profiles were measured in all the cores used in the study. 210Pb measurements were also made in cases where total 137Cs deposition was lower than predicted. For some sample sites, the data obtained showed correlated losses of both radionuclides, indicating that land disturbance and/or erosion had indeed occurred in these areas over the past 50 years, hence invalidating the use of those cores for carbon cycling studies. In a few cases a marked lack of correlation between these two radionuclides has made it necessary to hypothesize that chemical, rather than physical, processes have been partially responsible for the observed anomalies. Since results of this nature raise doubts about the reliability of the 137Cs method for identification of land disturbance, further investigation is warranted.  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