6 resultados para ASL R1781

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Data on sleeping site selection were collected for a group of black-and-white snub-nosed monkeys (Rhinopithecus bieti; around 80) at Mt. Fuhe, Yunnan, China (99degrees20'E, 26degrees25'N, about 3,000 m asl) from November 2000 to January 2002. At the site mainly three vegetation types were present in an elevation-ascending order: deciduous broad leaf forest, mixed coniferous and broad leaf forest, and dark coniferous forest. In addition, bamboo forest presented in areas burned in 1958. Sleeping sites (n = 10) were located in the coniferous forest, where trees were the tallest, bottommost branches were the highest, the diameter of crowns was the second largest, and the gradient of the ground was the steepest. Monkeys usually kept quiet during entering and staying at a sleeping site. The site choice and the quietness may be tactics to avoid potential predators. In the coniferous forest, however, monkeys did not sleep in the valley bottom where trees were the largest, but frequently slept in the middle of the slope towards the east/southeast, in the shadow of ridges in three other directions, to avoid strong wind and to access sunshine; in winter-spring, they ranged in a more southern and lower area than in summer-autumn. These may be behavioral strategies to minimize energy stress in the cold habitat. Monkeys often slept in the same sleeping site on consecutive nights, which reflected a reduced pressure of predation probably due to either the effectiveness of anti-predation through sleeping site selection, or the population decline of predators with increasing human activities in the habitat. The group's behavioral responses to interactive and sometimes conflicting traits of the habitat are site-specific and conform to expectations for a temperate zone primate.

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We collected data on diet and activity budget in a group of Rhinopithecus bieti at Tacheng (99degrees 18'E, 27degrees 36' N, between 2,700 - 3,700 m asl), Yunnan, from March 1999 to December 2000. We mainly recorded species-parts eaten with feeding scores from scanning state behaviors of one-male units in tree-crowns. We also conducted microscopic analysis of feces collected monthly. The subjects consumed 59 plant species, belonging to 42 genera in 28 families, of which 90 species-parts were distributed as follows: 21 in Winter, 38 in spring, 39 in Summer, 47 in autumn. Conversely, the group annually spent, on average, 35% of daytime feeding, 33% resting, 15% moving, and 13% in social activities. Seasonal changes are apparent in daytime budget and food item-related feeding time in tree-crowns, food remains in feces, and the number of species-parts eaten. Correlations within and between food items and time budget clearly indicate maximization of foraging effectiveness and minimization of energy expenditure. In consideration of reports from northern and southern groups, that which underlay the specific adaptation to the habitat appeared to be similar to those of other colobines. Thus, the ultimate factors for survival of the species are more hopeful than expected.

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从 1999 年4 月至2002 年六月间,对黑白仰鼻猴种群(Rhinopithecus bieti ) 的分布和生境状况进行了调查。与十年前的调查结果相比,本次调查新发现了4 个亚种群(指存在生境走廊的若干群体),但有5 个以前存在的群已经消失,现 存猴群数量为13 群,总体数量约为1200-1700 只。从西藏的芒康到云龙的龙马 山,随着海拔的降低,猴群可利用的植被类型也随之多样化。但由于砍伐、放牧、 开矿等因素的影响,猴群生境破碎化程度较高,连接猴群的生境走廊状况极差, 多数猴群孤立分布,并且存在小种群问题,生境走廊的维护和恢复已成为该物种 保护成功与否的关键。种群的总体数量下降了32%(不含4 个新发现的亚种群), 其中4 群数量下降,4 群持平,1 群有所增长,5 群消失,这不容乐观的状况给 我们保护敲响了警钟。此外,基于以前的研究结果,暗针叶林、针阔混交林和栎 树林均为其适宜生境,夏季高山牧场则是由当地居民为放牧而砍伐、焚烧高海拔 带的暗针叶林而形成的林间空地。我们使用了1997 年的卫星影像和1958 年的航 拍地图来估算适宜生境和夏季高山牧场的面积。结果表明;1)在1997 年,黑白 仰鼻猴的适宜生境面积为4169 km2,夏季高山牧场的面积为1923 km2。2)在近 40 年中,黑白仰鼻猴的适宜生境面积下降了31%(约1887 km2),而夏季高山牧 场的面积则增加了204%(约1291 km2)。3)森林斑块的平均面积从15.6 km2 下降到5.4 km2。此外,夏季高山牧场的面积与当地居民的人口数量增长之间呈 正相关关系 (R2 ≥ 0.53,p < 0.05)。除非当地居民的人口数量增长模式或者传统 的生产生活方式发生改变,这种破碎化趋势将继续下去。 从1999 年三月至2000 年十二月对云南塔城(99o18’E, 27 o36’N, 活动范围在 2,700 – 3700 m asl)的一群黑白仰鼻猴收集了食性和时间预算的数据。通过状态 行为扫描的方式,主要记录了树冠中单雄组食用植物种类—部位。同时用显微镜对每个月的粪便样本进行了显微分析,以此作为食性的补充数据。仰鼻猴食用属 于28 科、42 属的59 种植物,共计90 个食用的植物种类—部位,其中冬季利用 21 个植物种类—部位,春季38 个,夏季39 个,秋季47 个。另一方面,该群年 平均花费日活动时间的35%进食,33%休息,15%移动,13%社会行为。日活 动时间预算分配、摄食不同食物类别的时间、粪便中食物残留物及食用植物种 类―部位的数目存在着季节性变化。食物种类与时间分配之间和之内的相关显然 是为了最大化觅食效率与最小化能量消耗。考虑到来自北面与南面的群的相关报 道,这个种对生境的适应性似乎与其他疣猴没什么区别,并无特化之处。因此, 这个种的最终生存预期要比以前乐观。 我们利用整个塔城猴群沿地面通过开阔地或喝水的机会,使我们能记录野外 种群的大小和组成(如性比等)以及通过分析依次经过个体间的时间间隔以量化 反映社会组织单元之间和之内的空间距离,用统计分析的方式来量化描述社会组 织的模式,发现塔城猴群由9 个单雄单元(OMUs)、5 个多雄单元(MMUs)和2 个全雄单元(AMUs)组成, 单雄单元、多雄单元和全雄单元内的个体分别约占 总数的58%、34%和8%,无论在开阔峡谷地域或水潭旁,单元内的时间间隔显 著短于单元间的时间间隔(开阔峡谷地域:非配对 t 检验,df = 49; p < 0.01, 水潭:非配对t 检验,df = 35; p < 0.01)。 在单雄单元的成年不等性比和成 年雌性与婴猴的比例显著大于多雄单元(开阔峡谷地域:非配对t 检验,df = 40; p < 0.05,水潭:非配对t 检验,df = 16; p < 0.05)。在全雄单元中有大量的 性别不明的未成年个体。此外,加之某些个案描述,论述了多雄单元存在的可能 性及与全雄单元和单雄单元之间的关系。

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Plant traits and individual plant biomass allocation of 57 perennial herbaceous species, belonging to three common functional groups (forbs, grasses and sedges) at subalpine (3700 m ASL), alpine (4300 m ASL) and subnival (>= 5000 m ASL) sites were examined to test the hypothesis that at high altitudes, plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts, especially storage organs, as altitude increases, so as to geminate and resist environmental stress. However, results indicate that some divergence in biomass allocation exists among organs. With increasing altitude, the mean fractions of total biomass allocated to aboveground parts decreased. The mean fractions of total biomass allocation to storage organs at the subalpine site (7%+/- 2% S.E.) were distinct from those at the alpine (23%+/- 6%) and subnival (21%+/- 6%) sites, while the proportions of green leaves at all altitudes remained almost constant. At 4300 m and 5000 m, the mean fractions of flower stems decreased by 45% and 41%, respectively, while fine roots increased by 86% and 102%, respectively. Specific leaf areas and leaf areas of forbs and grasses deceased with rising elevation, while sedges showed opposite trends. For all three functional groups, leaf area ratio and leaf area root mass ratio decreased, while fine root biomass increased at higher altitudes. Biomass allocation patterns of alpine plants were characterized by a reduction in aboveground reproductive organs and enlargement of fine roots, while the proportion of leaves remained stable. It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots. In contrast to forbs and grasses that had high mycorrhizal infection, sedges had higher single leaf area and more root fraction, especially fine roots.

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In this work, crystallization and melting behavior of metallocene ethylene/alpha-olefin copolymers were investigated by differential scanning calorimetry (DSC) and atomic force microscopy (AFM). The results indicated that the crystallization and melting temperatures for all the samples were directly related to the long ethylene sequences instead of the average sequence length (ASL), whereas the crystallization enthalpy and crystallinity were directly related to ASL, that is, both parameters decreased with a decreasing ASL. Multiple melting peaks were analyzed by thermal analysis. Three phenomena contributed to the multiple melting behaviors after isothermal crystallization, that is, the melting of crystals formed during quenching, the melting-recrystallization process, and the coexistence of different crystal morphologies. Two types of crystal morphologies could coexist in samples having a high comonomer content after isothermal crystallization. They were the chain-folded lamellae formed by long ethylene sequences and the bundlelike crystals formed by short ethylene sequences. The coexistence phenomenon was further proved by the AFM morphological observation.

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The Tianshan Mountains is located about 1000-2000 km north of the India-Asia suture and is the most outstanding topography in central Asia, with transmeridional length of nearly 2500 km, north-southern wideness of ~ 300-500 km, peaks exceeding 7000 m above sea level (asl.), and average altitude of over 4000 m asl. Much of the modern relief of the Tianshan Range is a result of contraction driven by the collision of the India subcontinent with the southern margin of Asia, which began in early Tertiary and continues today. Understanding where, when and how the deformation of the Tianshan Mountains occurred is essential to decipher the mechanism of intracontinental tectonics, the process of foreland basin evolution and mountain building, and the history of climate change in central Asia. In order to better constrain the Cenozoic building history of the Tianshan Mountains and the climate change in the southern margin of the Junggar Basin, we carried out multiple studies of magnetostratigraphy, sedimentology, and stable isotopes of paleosol carbonate at the Jingou River section, which is located at the Huoerguosi anticline, the westernest one of the second folds and thrust faults zone in the northern piedmont of the Tianshan Mountains. The Jingou River section with a thickness of about 4160 m is continuous in deposits according to the observed gradual change in sedimentary environments and can be divided into five formations: Anjihaihe, Shawan, Taxihe, Dushanzi and Xiyu in upward sequence. Characteristic remamences were isolated by progressive thermal demagnetization, generally between 300 and 680℃. A total of 1133 out of 1607 samples yielded well-defined ChRMs and were used to establish the magnetostratigraphic column of a 3270-m-thick section from the exposed base of the Anjihaihe Formation to the middle of the Xiyu Formation. Two vertebrate fossil sites and a good correlation with the CK95 geomagnetic polarity time scale suggest that the section was deposited from ~30.5 to ~4.6 Ma and the age of the top of the Xiyu formation is ~2.6 Ma based on an extrapolation of the sedimentation rates. A plot of magnetostratigraphic age vs. height at the Jingou River section shows that significant increases in sedimentation rates as well as notable changes in depositional environments occurred at ~26-22.5 Ma, ~13-11 Ma and ~7 Ma, which represent the initial uplift of the Tianshan Mountains and two subsequent rapid uplift events. In addition, changes in sedimentation rates display characteristic alternations between increases and decreases, which probably indicate that the uplift of the Tianshan Mountains was episodic. We discussed the history of C4 biomass and climatic conditions in the southern margin of the Junggur Basin using the stable carbon and oxygen isotope composition of paleosol carbonates from the Jingou River section during ~17.5-6.5 Ma. The δ13C values indicate that the proportion of C4 biomass was uniform and moderate (15-20 %) during the interval of ~17.5-6.5 Ma. We proposed three hypotheses for this pattern of C4 biomass: (1) counteraction of two opposed factors (global cooling since ~15 Ma and thereafter increased dry and seasonality in central Asia) controlling the growth of C4 grasses, (2) variability in abundance of C3 grasses relative to C3 trees and shrubs if vegetation had ever changed in ecosystems, and (3) the higher latitude of the studied region. The δ18O values show a stepwise negative trend since ~13 Ma which may be attributed to three factors: (1) the temperature decreasing gradually after the middle Miocene (~15 Ma), (2) the increasing contribution of the moistures carried by the polar air masses from the Arctic Ocean to precipitation, and (3) the gradual retreat westward and disappearance of the Paratethys Ocean. Among them, which one played a more important role will need further study of the paleoclimate in central Asia.