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1.
The breeding habitat selection by houbara bustards in Mori, Xinjiang, China during the breeding seasons from April to June 1998–2000 was studied. Most of habitats chosen for breeding were short sub-shrubby and open areas close to high bushy patches. The nesting females clearly prefer low covered areas and avoid densely covered and high vegetation sites. The number of herb species was significantly smaller at nest sites than at randomly selected sites. Only the distance to the closest fox den contributed the most to discrimination between successful and predated nests. The average distance to the closest fox den was significantly longer at successful nests than at depredated nests. Vegetative density, plant species richness, topography and distance to the closest fox den are possibly the most important factors that determined the nest sites selection of houbara bustard. The displaying males clearly prefer low covered areas and avoid densely covered and high vegetation sites. The vegetation density and number of plant species at display sites was significantly lower than that at randomly selected sites. The average distance to the closest bushy patch was significantly shorter at display sites than at random sites. Plant species richness, vegetative density, vegetative cover and distance to the bushy patches are possibly the most important factors for the display sites selection of houbara bustard 相似文献
2.
The breeding habitat selection by houbara bustards in Mori, Xinjiang, China duringthe breeding seasons from April to June 1998-2000 was studied. Most of habitats chosen forbreeding were short sub-shrubby and open areas close to high bushy patches. The nesting re-males clearly prefer Iow covered areas and avoid densely covered and high vegetation sites. Thenumber of herb species was significantly smaller at nest sites than at randomly selected sites.Only the distance to the closest fox den contributed the most to discrimination between successfuland predated nests. The average distance to the closest fox den was significantly longer at suc-cessful nests than at depredated nests. Vegetative density, plant species richness, topography anddistance to the closest fox den are possibly the most important factors that determined the nestsites selection of houbara bustard. The displaying males clearly prefer Iow covered areas andavoid densely covered and high vegetation sites. The vegetation density and number of plant spe-cies at display sites was significantly lower than that at randomly selected sites. The average dis-tance to the closest bushy patch was significantly shorter at display sites than at random sites.Plant species richness, vegetative density, vegetative cover and distance to the bushy patches arepossibly the most important factors for the display sites selection of houbara bustard. 相似文献
3.
The protoliths of mafic-ultramafic plutons in the northern Dabie Mts. (NDM) (Hubei) include pyroxenite and gabbro. The zircon
U-Pb dating for a gabbro suggests that emplacement of mafic magma took place in the post-collisional setting at the age of
122.9±0.6 Ma. It is difficult to obtain a reliable Sm-Nd isochron age, due to disequilibrium of the Sm-Nd isotopic system.
Two hornblende 40Ar/ 39Ar ages of 116.1±1.1 Ma and 106.6±0.8 Ma may record cooling of metamorphism in the mafic-ultramafic plutons in Hubei below
500°C. The hornblende 40Ar/ 39Ar ages for the mafic-ultramafic rocks in Hubei are evidently 15–25 Ma younger than those for the same rocks in Anhui, indicating
that there is a diversity of the cooling rates for the mafic-ultramafic rocks in Hubei and Anhui. The difference in their
cooling rates may be controlled by the north-dipping normal faults in the NDM. The intense metamorphism occurring in the mafic-ultramafic
rocks in Hubei may result from the Yanshanian magmatic reheating and thermal fluid action induced by the Cretaceous migmatization.
The geochemical similarity of these mafic-ultramafic rocks wherever in Hubei and Anhui may be attributed to the same tectonic
setting via an identical genetic mechanism. 相似文献
4.
Short sediment cores retrieved from Bosten Lake, the largest inland freshwater lake in China, were used to explore humidity and precipitation variations in arid central Asia during the past millennium. The chronology of the cores was established using 137Cs, 210Pb and AMS 14C dating re- sults. Multi-proxy high-resolution analysis, including pollen ratios of Artemisia and Chenopodiaceae (A/C), carbonate content and grain size, indicates that the climate during the past millennium can be divided into three stages: a dry climate between 1000―1500 AD, a humid climate during the Little Ice Age (LIA) (c. 1500―1900 AD), and a warm dry period after 1900 AD. On centennial timescales, the climate change in northwestern China during the past 1000 years is characterized by oscillations between warm-dry and cold-humid climate conditions. All the proxies changed significantly and indi- cate increased precipitation during the LIA, including increased pollen A/C ratios and pollen concen- trations, decreased carbonate content and increased grain size. The humid period during the LIA re- corded by the Bosten Lake sediments is representative of arid central Asia and is supported by nu- merous records from other sites. During the LIA, the water runoff into the Keriya River and Tarim River in the Tarim Basin increased, while the ice accumulation in the Guliya ice core increased. Additionally, the lake levels of the Aral and Caspian Sea also rose, while tree-ring analysis indicates that precipita- tion increased. We hypothesize that both the lower temperature within China and the negative anomalies of North Atlantic Oscillation (NAO) during this period may have contributed to the humid climate within this area during LIA. 相似文献
5.
A total of 1504 larval and 31 pupal Simuliidae were caught from March 2000 to February 2001 at the Weidlingbach, a fourth order tributary of the Danube near Vienna, Austria, using a modified box sampler (sampling area = 2116 cm 2) at 12 sampling stations from source to mouth. From the six species collected, Prosimulium tomosvaryi (Enderlein) and two species of the Simulium ornatum-group ( S. trifasciatum Curtis and S. ornatum Meigen) accounted for 97.5% of the total. Based on head width, instars 1–7 were collected in the S. ornatum-group and instars 2–7 in P. tomosvaryi; from two of the remaining species [ Simulium ( Nevermannia) cryophilum (Rubzov) and S. ( N.) vernum Macquart], only pupae were sampled. The S. ornatum-group was most abundant on coarse substrates (median = 55.9 mm) exposed to high water velocity (median = 55.9 cm/s; range = 9–83 cm/s); the latter was also true for P. tomosvaryi although it favoured smaller sediment grain sizes (median = 32.4 mm). Species richness and population density increased from source to mouth. At sampling sites near the source Simuliidae were completely lacking. In headwaters only P. tomosvaryi was present, whereas the S. ornatum-group and Simulium ( Simulium) argyreatum Meigen was collected exclusively near the mouth. 相似文献
6.
2017年5月11日,新疆喀什地区塔什库尔干县发生5.5级地震。地震造成8人死亡、31人受伤以及财产损失,属于典型的“小震大灾”。按照一般的地震灾害损失快速评估方法,得到的评估结果与实际结果差别较大。为探讨评估结果偏离的原因,本文对不同地震损失评估方案进行比较分析,探讨了地震致灾性(地震影响场分布)、承灾体(人口)分布等因素对地震损失评估结果的影响。结果表明在此次地震快速评估中,基于宏观震中确定的地震影响场较微观震中更接近实际分布;地震烈度衰减的平均估计模型给出的地震烈度区面积明显小于实际面积;极震区存在抗震能力相对低的土木、砖木结构房屋,是造成该地震震级相对小而生命损失相对大的“小震大灾”的重要原因。对比分析结果表明,提高人口、房屋建筑等风险暴露数据的空间精准性,改善地震震中定位与地震影响场估计的准确性,将有助于提高地震应急损失评估的准确性。 相似文献
7.
Shaly sands reservoir is one of the most distributive types of the oil(gas)-bearing reservoirs discovered in China, and low resistivity oil(gas)-bearing reservoirs are mostly shaly sands reservoirs. Therefore, shaly sands reservoir conductive model is the key to evaluate low resistivity oil(gas)-bearing reservoirs using logging information. Some defects were found when we studied the clay distribution type conductive model, dual-water conductive model, conductive rock matrix model, etc. Some models could not distinguish the conductive path and nature of microporosity water and clay water and some models did not consider the clay distribution type and the mount of clay volume. So, we utilize the merits,overcome the defects of the above models, and put forward a new shaly sands conductive model-dual water clay matrix conductive model (DWCMCM) in which dual water is the free water and the microporosity water in shaly sands and the clay matrix(wet clay) is the clay grain containing water. DWCMCM is presented here, the advantages of which can tell the nature and conductive path from different water (microporosity water and freewater), in consid-eration of the clay distribution type and the mount of clay volume in shaly sands. So, the results of logging interpretation in the oil(gas)-bearing reservoirs in the north of Tarim Basin area, China with DWCMCM are better than those interpreted by the above models. 相似文献
9.
No .1FaultActivitiesandPaleoearthquakeEventsalongthePiedmontFault (Wujumengkou_DongfengcunSegment)ofMt.Serteng ,InnerMongoliaYangXiaoping ,RanYongkang ,HuBoandGuoWensheng ( 1 )……………………………StudyontheHorizontalDeformationStrainFieldintheCentralandNorthernPartsofYunnanProvinceLiYanxing ,GuoLiangqianandZhangZhongfu ( 1 4 )………………………………………ActivityTendencyandDynamicCharacteristicsofShanxiFaultZoneYangGuohua ,WangMin ,HanYueping ,ZhouXiaoyan ,ZhangZhongfu ,… 相似文献
11.
2005年8月26日新疆墨玉县发生了MS5.4地震,震区附近强烈有感,并造成了一定程度的破坏。本文从地震基本参数、震群监测、震源机制解、发震构造、地震序列等方面概述了这次地震序列。 相似文献
12.
艾比湖流域是西北地区重要的生态屏障,维持着该地区乃至整个新疆北部的生态平衡.艾比湖流域水环境的好坏关系着当地经济和流域的可持续发展.然而,针对艾比湖流域长期水质变化、营养状况和健康风险的研究较少,故基于艾比湖流域2005-2020年12个断面长时间序列的监测数据,利用加拿大水质指数(Canadian water qua... 相似文献
14.
No.1Characteristics of Energy Accumulation and Release of Seismogenic Tectonics and Seismic RiskAnalysis in Some Areas inthe Tianshan Mountains,Xinjiang Shen Jun,Li Yingzhen and Wang Yipeng…………………………………………(1)Regional Tectonic Deformation B 相似文献
17.
No .1Study onthe Determination of the Significant National Seismic Monitoring and Protection Regions Zhang Guomin,Fu Zhengxiang,Wang Xiaoqing,and Liu Guiping……………(1)Reviewof Research Progresses on the Science of Earthquake Underground Fluid in China During theLast 40 Years Liu Yaowei………………………………………………………………………(16)Study onthe Triggering Effect of the October ,2005 PakistanMW7 .6 Earthquake onIts Aftershocks Wan Yongge,Shen Zhengkang,and Shang Dan… 相似文献
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