4 resultados para stepping stones
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
揭示水体中繁殖的两栖动物在异质性景观中的空间扩散特点,探讨景观面积丧失和破碎化对于两栖动物的影响,为两栖动物的保护提供理论依据。本文以四川西北部若尔盖湿地自然保护区的高原林蛙(Rana kukunoris)为研究对象,通过运用地理信息系统及建立景观模型等方法,在分析若尔盖湿地自然保护区范围内现有景观格局的基础上,建立了高原林蛙的景观扩散模型,并模拟了“沼泽→草甸”的湿地逆演化过程下高原林蛙的空间分布与景观连接的变化特点。主要结果是: 1.若尔盖湿地自然保护区呈典型的沼泽—草甸式斑块—基质景观格局。草甸面积占整个景观面积的79.42%,景观蔓延度指数(CONTAG)为79.00远离最小值0而更趋向于最大值100,面积和景观蔓延度指数表明草甸是整个景观中面积占绝对优势且景观连接好的类型,构成了景观的基质,对景观的动态格局演变起主导作用。沼泽面积仅占整个景观面积的18.08%,但却是整个景观中斑块数目最多的单元,占所有斑块数的82.9%。因此沼泽斑块与草甸基质之间的动态结构对高原林蛙的扩散起着决定性的作用。 2.空间扩散模型表明,其它类型的景观不但扩展了高原林蛙的活动范围,而且也为高原林蛙在不同沼泽斑块间的连接提供了通道。高原林蛙的空间扩散区域使得彼此间成斑块化隔离状分布的沼泽形成了潜在景观功能连接,促进了不同斑块间物种的交流。小型沼泽作为垫脚石(stepping-stone),使得整个景观中的相隔距离较远的大型斑块联结为一个功能整体,促进了高原林蛙在整个景观中的相互动态联系。 3.模拟“沼泽→草甸”的湿地逆演化过程表明,大量小型沼泽湿地的消失将会 对在沼泽中繁殖并扩散到其它景观类型中去的高原林蛙造成潜在影响。逆演化过程不仅使沼泽斑块的分布范围,沼泽源斑块的面积和空间扩散面积减少,而且对景观连接也有很大影响。小型沼泽的消失,将使得景观斑块的功能连接变小,使得依靠小型沼泽作为跳板的动物在沼泽斑块之间的移动将变得更加困难。 本文是对生境丧失与破碎化影响下两栖动物的行为反应的一种尝试。影响模型的因素很多,包括动物对各种类型景观的偏好程度,地理数据的精度,及模型的可靠程度都是制约模型准确度的因素。 The spatial diffusion of water—breeding amphibian through heterogeneous landscape and the effects of landscape losing and fragmentation to amphibian were the core theory of the landscape ecology of amphibian. Geographical information system (GIS) and landscape model were used to model the diffused area of Rana kukunoris in Zoige Wetland Natural Reserve. Model was also used to analysis the spatial distribution variation of R. kukunoris and the change of landscape connectivity when simulated the retrogressive succession of landscape. The main results are below: 1. There was peatland—meadow pattern which was typical patch—matrix landscape pattern in Zoige Natural Reserve. The meadow area occupied 79.42% of the entire landscape area, contagion index (CONTAG) was 79.00 which was far away the minimum value (0) but tend to the maximum value (100). Both of these showed that meadow was the largest part and the most continue units. It was shown that meadow was matrix of the landscape, which evolved the leading role to the landscape dynamic pattern. Though their area only occupies 18.08% of entire landscape area, peatlands were according to 82.9% of the total patches. Dynamic of the pattern between peatlands and meadows decided the spatial diffusion of R. kukunoris. 2.The model indicated that the other types of landscape not only expanded diffusion of R. kukunoris, but also have provided the potential channels for frog's connections among different peatlands. The spatial diffusion zone of R. kukunoris forced isolated patch peatlands to be potential landscape functional connectivity. The small peatlands, as stepping-stone, made the large peatlands connect as a functional one and promoted the integrated and dynamic connectivity of R. kukunoris in the whole landscape. 3. The simulation of “peatlands→meadows”retrogressive succession process indicated that the decrease of small peatlands will have potential effect to R. kukunoris because they must bred in peatlands and diffuse to other type of the landscape. Retrogressive succession process not only made the decrease of distribution of peatlands, patches number of peatlands and diffused area of R. kukunoris, but also reduced the connectivity among source patches. As stepping-stone, the disappearance of small peatlands will made the migration of R. kukunoris among patches more difficult. The model was an experiment of the amphibian behavior reaction to habitat losing and fragmentation. There were many factors that could influence the accuracy of model, such as the preference of animals to each type of landscape, the geographical data precision, reliable degree of model.
Resumo:
沙蜥属Phrynocephalus Kaup,1825隶属于爬行纲(Reptilia)有鳞目(Squamata)蜥蜴亚目(Lacertilia)鬣蜥科(Agamidae),是欧亚大陆荒漠和稀疏草原常见蜥蜴。沙蜥属的分类及系统演化关系、地理分布格局与新生代第三纪以来古地中海的变迁、青藏高原的抬升及亚洲内陆干旱荒漠化的过程有密切的关系,长期以来有关沙蜥属的研究一直受到中外学者们的关注。由于沙蜥属地理分布广、形态变异大、体色和斑纹变化复杂,虽然前人使用过许多形态性状来描述和分类沙蜥属物种,但是仍然存在许多问题。性状的分类学意义不明确是造成这些问题的主要原因之一,因此本研究针对沙蜥属常用的鉴别性状进行分类意义的分析,希望能对沙蜥属物种鉴定及分类学其它研究有所裨益。 中国沙蜥属物种主要分布于西北的干旱荒漠区域及青藏高原的大部分地区,大约为18种。 本文研究了中国境内12种沙蜥:青海沙蜥(Phrynocephalus vlangalii)、西藏沙蜥(P. theobaldi)、南疆沙蜥(P. forsythii)、变色沙蜥(P. versicolor)、旱地沙蜥(P. helioscopus)、荒漠沙蜥(P. przewalskii)、乌拉尔沙蜥(P. guttatus)、草原沙蜥(P. frontalis)、叶城沙蜥(P. axillaris)、白稍沙蜥(P. koslowi)、无斑沙蜥(P. immaculatus)和白条沙蜥(P. albolineatus),对它们的65项外部形态性状进行了观察和测量,其中数量性状29项、质量性状36项。评价了这些性状的序级性、间断性和代表性,结论如下: 1. 对于数量性状,得出了适合各级分类的数值区间; 2. 给出了在不同序级上适合分类的质量性状。 并利用各性状评价的结果,给出12种沙蜥的检索表,以及对中国沙蜥物种某些尚存在争议的问题进行了探讨。 详细记录了青海沙蜥红原亚种的骨骼系统,首次发现并命名了肘骨(elbow bone)和垫骨(stepping bone),为沙蜥属系统学研究补充了骨骼方面的证据;解剖了乌拉尔沙蜥、旱地沙蜥、荒漠沙蜥的雌体和雄体的骨骼系统,并在14项骨骼形态性状上对这3种沙蜥进行了比较。 Phrynocephalus (Squamata,Agamidae) is a familiar genus of lizards inhabited desert and sparse steppes in Eurasia. The taxonomics, phylogenetics and distribution pattern of Phrynocephalus are relative intensely to these events: the vicissitudes of the archaic Mediterranean sea since the Cainozoic, the uplift of Qingzang Plateau and the expending arid areas in the inland of Asia. Owing to the wide distribution, the large variability of the morphology and the different colors in Phrynocephalus, it is difficult to identify them. Tough many morphological characters are used to describe and discriminate them,a lot of questions still exist. One of the most important reasons is the confusion in the morphological characters. In this study, we demonstrate the validity and the invalidity of the familiar characters. There are about 18 species of the genus Phrynocephalus in China, which exist in arid desert in Northwest China and Qingzang Plateau. Twelve Chinese species was analyzed in this paper. They are P. vlangalii,P. theobaldi,P. forsythia,P. versicolor,P. helioscopus,P. przewalskii,P. guttatus,P. frontalis,P. axillaris,P. koslowi,P. immaculatus,P. albolineatus. We measure 29 quantitative characters and observe 36 qualitative characters in each individual. Through analyzing these characters, we made some conclusions as follows: 1. to every quantitative character, we get a clear numeric area to discriminate the different operational taxonomic units. 2. we chose the valid qualitative characters in these operational taxonomic units. This paper is the first to describe the “elbow bone”, which is a bone in pectoral appendage equivalent to patella,and “stepping bone”, which is a bone under carpal. A detailed description of the skeletal system of female Phrynocephalus vlangalii hongyuanensis was conducted. We also anatomise the skeletal systems of three species: P. guttatus,P. przewalskii,P. helioscopus, and compare or contrast 14 skeletal characters in them. What’s more,this paper offers some suggestions to the questions of Chinese Phrynocephalus species and keys to 12 species of Phrynocephalus basing on our conclusions on the evaluation of the morphological characters.
Resumo:
随着移动机器人应用范围的日益扩展,在动态、非结构环境下提高自主行为能力已经成为移动机器人研究领域的首要问题。本文以“863”高技术计划资助项目“复合机构移动机器人构型在线优化及控制共性技术研究”为依托,以沈阳自动化研究所自主研发的“模块化便携式履带式移动机器人”为实验平台,针对实时非线性在线估计共性方法及其在移动机器人行为环境的自主建模及环境适应运动控制等方面的引用,展开深入研究,旨在提高移动机器人对动态、非结构环境的适应能力。本论文的主要内容如下:首先,研究了二维环境下移动机器人的滑动效应建模问题。将滑动效应表达为三个时变的滑动参数,建立起带滑动参数的移动机器人运动学和动力学模型,探讨了运动模型的能控性和能观性,并结合动力学分析对侧滑参数的深层机制进行了分析。本研究内容为后续估计和控制问题的验证提供了仿真对象。其次,介绍了四种非线性在线估计共性方法,即基于线性化理论的EKF估计方法、基于无色变换的UKF估计方法、基于UKF重要性采样的UPF估计方法和基于未知但有界噪声假设的ESMF估计方法,建立了具有一般性的移动机器人在线建模结构;针对上述四种估计方法在移动机器人在线建模方面的应用进行了分析和比较研究,重点强调了保边界集员估计方法独有的优势。第三,针对ESMF估计方法本身存在的数值稳定性差、时间复杂度高以及滤波器参数难于选择的缺点,提出了基于UD分解的自适应扩展集员估计方法,将包络矩阵UD分解、观测序列更新和选择更新、滤波器参数的次优自适应选择三种策略结合起来,以提高ESMF的实时性和鲁棒性,针对滑动参数估计的仿真结果表明了所提方法的有效性。第四,针对两类带有参数不确定性的移动机器人控制问题,提出了在线估计与控制相结合的方法。其一是带未知时变滑动参数的移动机器人跟踪控制问题,采用非线性估计方法对未知参数进行在线估计,并结合动态反馈线性化和PD控制律两种控制策略,以达到全局指数跟踪的收敛结果。其二是带滑动参数和几何参数等混合不确定性的移动机器人点镇定控制问题,采用state scaling和back-stepping方法,对参数未知但有界的情形获得了全局指数收敛的点镇定结果。最后,对三维情况下移动机器人周边地形环境的在线建模问题进行了研究。采用数字高程网格地图表达地形环境,介绍了基于高斯和模型的地形估计方法。针对高斯和模型本身近似条件所引起的应用困难和精度较差的缺点,提出了基于区间集员估计理论的地形环境模型估计方法,避免了高斯和估计方法中存在的大量近似条件,改善了地形估计性能,并可获得地形的保证边界估计信息,为机器人的运动控制和构型调整提供必需的先验知识。仿真和实验研究均证明了集员地形估计方法相对于高斯和地形估计方法的优越性。
Resumo:
The Grove Mountains, including 64 nunataks, is situated on an area about 3200km2 in the inland ice cap of east Antarctica in Princess Elizabeth land (72o20'-73°101S, 73°50'-75o40'E), between Zhongshan station and Dome A, about 450km away from Zhongshan station (69°22'S, 76°22'E). Many workers thought there was no pedogenesis in the areas because of the less precipitation and extreme lower temperature. However, during the austral summer in 1999-2000, the Chinaer 16 Antarctic expedition teams entered the inland East Antarctica and found three soil spots in the Southern Mount Harding, Grove Mountains, East Antarctica. It is the first case that soils are discovered in the inland in East Antarctica. Interestingly, the soils in this area show clay fraction migration, which is different from other cold desert soils. In addition, several moraine banks are discovered around the Mount Harding. The soil properties are discussed as below. Desert pavement commonly occurs on the three soil site surfaces, which is composed of pebbles and fragments formed slowly in typical desert zone. Many pebbles are subround and variegated. These pebbles are formed by abrasion caused by not only wind and wind selective transportation, but also salt weathering and thaw-freezing action on rocks. The wind blows the boulders and bedrocks with snow grains and small sands. This results in rock disintegration, paved on the soil surface, forming desert pavement, which protects the underground soil from wind-blow. The desert pavement is the typical feature in ice free zone in Antarctica. There developed desert varnish and ventifacts in this area. Rubification is a dominant process in cold desert Antarctic soils. In cold desert soils, rubification results in relatively high concentrations of Fed in soil profile. Stained depth increases progressively with time. The content of Fed is increasing up to surface in each profile. The reddish thin film is observed around the margin of mafic minerals such as biotite, hornblende, and magnetite in parent materials with the microscope analyzing on some soil profiles. So the Fed originates from the weathering of mafic minerals in soils. Accumulations of water-soluble salts, either as discrete horizons or dispersed within the soil, occur in the soil profiles, and the salt encrustations accumulate just beneath surface stones in this area. The results of X-ray diffraction analyses show that the crystalline salts consist of pentahydrite (MgSO4-5H2O), hexahydrite (MgSO4-6H2O), hurlbutite (CaBe2(PO4)2), bloedite (Na2Mg(S04)2-4H2O), et al., being mainly sulfate. The dominant cations in 1:5 soil-water extracts are Mg2+ and Na+, as well as Ca2+ and K+, while the dominant anion is SO42-, then NO3-, Cl- and HCO3-. There are white and yellowish sponge materials covered the stone underside surface, of which the main compounds are quartz (SiO2, 40.75%), rozenite (FeSOKkO, 37.39%), guyanaite (Cr2O3-1.5H2O, 9.30%), and starkeyite (MgSO4-4H2O, 12.56%). 4) The distribution of the clay fraction is related to the maximum content of moisture and salts. Clay fraction migration occurs in the soils, which is different from that of other cold desert soils. X-ray diffraction analyses show that the main clay minerals are illite, smectite, then illite-smectite, little kaolinite and veirniculite. Mica was changed to illite, even to vermiculite by hydration. Illite formed in the initial stage of weathering. The appearance of smectite suggests that it enriched in magnesium, but no strong eluviation, which belongs to cold and arid acid environment. 5) Three soil sites have different moisture. The effect moisture is in the form of little ice in site 1. There is no ice in site 2, and ice-cement horizon is 12 cm below the soil surface in site 3. Salt horizon is 5-10 cm up to the surface in Site 1 and Site 2, while about 26cm in site 3. The differentiation of the active layer and the permafrost are not distinct because of arid climate. The depth of active layer is about 10 cm in this area. Soils and Environment: On the basis of the characteristics of surface rocks, soil colors, horizon differentiation, salt in soils and soil depth, the soils age of the Grove Mountains is 0.5-3.5Ma. No remnants of glaciations are found on the soil sites of Mount Harding, which suggests that the Antarctic glaciations have not reached the soil sites since at least 0.5Ma, and the ice cap was not much higher than present, even during the Last Glacial Maximum. The average altitude of the contact line of level of blue ice and outcrop is 2050m, and the altitude of soil area is 2160m. The relative height deviation is about 110m, so the soils have developed and preserved until today. The parental material of the soils originated from alluvial sedimentary of baserocks nearby. Sporepollen were extracted from the soils, arbor pollen grains are dominant by Pinus and Betula, as well as a small amount Quercus, Juglans, Tilia and Artemisia etc. Judging from the shape and colour, the sporepollen group is likely attributed to Neogene or Pliocene in age. This indicates that there had been a warm period during the Neogene in the Grove Mountains, East Antarctica.