Use of high spectral resolution remote sensing to determine leaf palatability of eucalypt trees for folivorous marsupials     

Steve Dury  Brian Turner  Bill Foley  Ian Wallis 《International Journal of Applied Earth Observation and Geoinformation》2001,3(4):328

In this study we assess the feasibility of remotely measuring canopy biochemistry, and thus the potential for conducting large-scale mapping of habitat quality. A number of studies have found nutrient composition of eucalypt foliage to be a major determinant of the distribution of folivorous marsupials. More recently it has been demonstrated that a specific group of secondary plant chemicals, the diformylphloroglucinols (DFPs), are the most important feeding deterrents, and are thus vital determinants of habitat quality. We report on the use of laboratory spectroscopy to attempt to identify one such DFP, sideroxylonal-A, in the foliage of Eucalyptus melliodora, one of the few eucalypt species browsed by folivorous marsupials. Reflectance spectra were obtained for freeze-dried, ground leaves using near infrared spectroscopy (NIRS) and for both oven-dried and fresh whole leaves using a laboratory-based (FieldSpec) spectroradiometer. Modified partial least squares (MPLS) regression was used to develop calibration equations for sideroxylonal-A concentration based on the reflectance spectra transformed as both the first and second difference of absorbance (Log 1/R). The predictive ability of the calibration equations was assessed using the standard error of calibration statistic (SECV). Coefficients of determination (r²) were highest for the ground leaf spectra (0.98), followed by the fresh leaf and dry leaf spectra (0.94 and 0.87, respectively). When applied to independent validation sub-sets, sideroxylonal-A was most accurately predicted from the ground leaf spectra (r² = 0.94), followed by the dry leaf and fresh leaf spectra (0.72 and 0.53, respectively). Two spectral regions, centred on 674 nm and 1394 nm, were found to be highly correlated with sideroxylonal-A concentration for each of the three spectral data sets studied. Results from this study suggest that calibration equations derived from modified partial least squares regression may be used to predict sideroxylonal-A concentration, and hence leaf palatability, of Eucalyptus melliodora trees, thereby indicating that the remote estimation of habitat quality of eucalypt forests for marsupial folivores is feasible.  相似文献   

Smooth constraint inversion technique in genetic algorithms and its application to surface wave study in the Tibetan Plateau     

吴建平  明跃红  曾融生 《地震学报(英文版)》2001,14(1):49-57

IntroductionThe dispersion phenomena, which can be observed when surface wave travels through the Earth interior, has been extensively applied in investigating the velocity structure of the Earth interior. Usually, the dispersion curve is a nonlinear function of the thickness, S and P wave velocities and density of each layer. Because surface wave inversion is a multiple-minima problem, the result strongly depends on the initial model in traditional linear inversion. Genetic algorithm (GA) …  相似文献   

Comparing field and laboratory breakdown rates of coarse particulate organic matter: Sediment dynamics mask the impacts of dissolved nutrients on CPOM mass loss in streams     

Bernd Spänhoff  Clemens Augspurger  Kirsten Küsel 《Aquatic Sciences - Research Across Boundaries》2007,69(4):495-502

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Fossil nothofagaceous leaves from the Eocene of western Antarctica and their bearing on the origin, dispersal and systematics of Nothofagus     

Li HaoMin  Zhou ZheKun 《中国科学D辑(英文版)》2007,50(10):1525-1535

Fossil leaves resembling Nothofagaceae have been investigated from the Eocene of western Antarctica and a new form genus Nothofagofolia is proposed for these kinds of fossils. Some new specimens belonging to this form genus are described. They were collected from the Fossil Hill locality of Fildes Peninsula, King George Island, South Shetland Islands, western Antarctica. Two new species, two new combinations and an unnamed species are reported. A number of published Nothofagus leaf fossils from the same locality are discussed and revised. As a result of these studies of Nothofagus leaf morphology, we conclude that (1) Nothofagus probably originated in high latitudes of the Southern Hemisphere during the middle-late Late Cretaceous and diversified, dispersed gradually to the lower latitudes of the same hemisphere; (2) leaf morphological characters are significant for the systematics of the family Nothofagaceae, especially at the intrageneric level; and (3) extant species of Nothofagus known from southern temperate areas have more primitive leaf morphological characters and lower leaf ranks than those from tropical mountains as well as those of the Fagaceae and Betulaceae. Supported by the Foundation of State Key Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology and Palaoentology, Chinese Academy of Sciences (Grant No. 013106), the National Natural Science Foundation of China (Grant No. 30670159) and the Fund of Innovation Program by Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences  相似文献   

基于卫星遥感数据改进区域尺度的显热通量模型     

宋小宁  赵英时  冯晓明 《地理与地理信息科学》2007,23(1):36-38

以西北半干旱地区的内蒙古农牧交错地带锡林郭勒盟为研究区，以不同退化程度的草地为研究对象，通过叶面积指数计算各像元的动力传输粗糙度长度，以改进显热通量算法；并结合植被／土壤组分温度分别计算基于亚像元的植被／土壤的显热通量。由敏感性分析和模型验证表明，改进的显热通量算法能够提高区域尺度的能量平衡计算精度。  相似文献   

基于室内光谱测量的玉米单叶偏振与二向性反射关系研究     

宋开山  张柏  赵云升  王宗明  杜佳 《遥感学报》2007,11(5):632-640

本研究利用多角度光度计实测了玉米单叶的偏振反射比与二向反射比数据。该光度计能够在不同的观测天顶角、入射天顶角和方位角下测量目标物的偏振反射和二向反射,获得地物目标在2π空间的多角度观测数据。通过分析实测的偏振反射和二向反射数据,得出了玉米单叶的偏振反射与二向反射之间关系密切,最大与最小偏振反射比之和的平均数约等于同等观测条件下玉米叶片的二向反射比。该研究成果为植被遥感监测做出了一种新的尝试,并且对偏振光遥感、多角度遥感的深入研究与应用提供了依据。  相似文献   

科尔沁沙地30种植物叶凋落物CO₂释放量及释放速率的研究     

孟庆涛  李玉霖  赵学勇  李玉强  赵玉萍 《中国沙漠》2007,27(6):960-967

 采用可以有效控制环境因子的室内土壤培养试验，初步研究了科尔沁沙地30种植物叶凋落物的CO₂释放量及释放速率。结果表明：①在28 d培养期内，不同植物叶凋落物释放的CO₂量差异很大，其中，多年生植物叶凋落物CO₂释放量平均值大于一年生植物，但二者之间的差异不显著；禾本科植物叶凋落物CO₂释放量平均值明显小于其他植物，二者之间呈显著差异。②在28 d培养期内，不同植物叶凋落物每四天CO₂释放速率差异很大。一年生与多年生植物叶凋落物28 d内每四天释放CO₂的速率无显著差异；禾本科与其他植物叶凋落物每四天释放CO₂的速率在培养的前16 d差异呈显著，而后差异消失。③植物叶凋落物的全碳含量，氮含量，C／N，灰分/N及灰分含量不同造成CO₂释放量及释放速率的差异。叶凋落物28 d释放CO₂的量与叶凋落物初始碳含量及灰分含量均无相关关系，与叶凋落物初始氮含量呈显著正相关，与叶凋落物C／N及灰分／N呈显著负相关。叶凋落物培养期内每四天释放CO₂的速率与叶凋落物初始碳含量无相关关系；叶凋落物0\_20天释放CO₂的速率与叶凋落物初始氮含量呈显著正相关，与叶凋落物C／N呈显著负相关；叶凋落物9\_28天CO₂释放速率与灰分／N呈显著负相关；培养后期（17\_28天）的CO₂释放速率与灰分含量呈显著负相关。  相似文献   

基于植被信息遥感反演的东亚飞蝗监测研究     

吴彤  倪绍祥  李云梅  蒋建军  陈健 《地理与地理信息科学》2006,22(2):25-29

植被是东亚飞蝗发生和成灾的重要指示因子。运用遥感技术对植被生长进行监测,对东亚飞蝗的预测和防治具有重要意义。以河北省黄骅市为研究区,利用实地获取的植被冠层孔隙度数据反算的LAI数据以及Landsat-5 TM影像提取的各种VI数据,进行了LAI(LAI-2000改进型算法的反算结果)与TM影像上反演的VI之间的相关分析。结果表明,RDVI最适合反映研究区植被生长状况。分析RDVI与飞蝗发生面积的关系,发现两者呈负线性相关,即随着RDVI减小,飞蝗的发生面积呈线性增大。  相似文献   

喀斯特山区先锋植物叶片解剖特征及其生态适应性评价--以贵州花江峡谷区为例   总被引：13，自引：0，他引：13  

容丽  王世杰  刘宁  杨龙 《山地学报》2005,23(1):35-42

通过研究贵州西南部典型喀斯特植被退化区花江峡谷植被现状,选取具一定经济价值和推广价值的先锋植物,采用生物显微制片技术与数理统计方法相结合,报导了6科10种分属不同生活型的植物叶片的解剖结构特征,并进行了比较和解剖因子分析。结果表明研究区喀斯特先锋植物叶片在不同种类之间具有明显差异,这些差异除受遗传因子控制外,环境因子(主要为光照和水分)也有重要作用;生活型不同对先锋植物叶片特征有一定影响,但未表现出规律性。根据叶片适应特征的差异,10种先锋植物可分为3种类型,即旱生或阳生叶类型的构树(Broussonetia papyrifera)、火棘(pyracantha fortuneana)、刺槐(Robinia pseudoacacia)、白三叶(Trifolium repens);偏中生叶类型(香椿的Toona sirensis)、顶坛花椒(Zanthaxylum pinum var．dingtanensis)、黔滇木蓝(In-digofera esquirolii)、忍冬(Lomicera japonica)、紫云英(Astragalus sinicus);偏阴生叶类型的繁缕(Stellaria media)。  相似文献   

基于光谱信息的遥感图像空间域自适应滤波   总被引：5，自引：0，他引：5  

吴传庆  赵永超  童庆禧  郑兰芬 《遥感学报》2004,8(1):51-55

遥感图像往往由于内外因素的干扰含有各种噪声 ,为提高图像质量人们对其进行滤波。常规的滤波方式完全基于图像空间域 ,在消除异常点使图像平滑的同时使边界变得不清楚从而使图像模糊 ;或者正相反 ,在边缘信息得到增强时也放大了图像噪声而使图像变得粗糙。该文的自适应滤波方法充分利用多光谱和高光谱遥感图像的光谱维信息 ,滤波时不仅要使均匀的地块得到平滑 ,而且要使地块间的边缘、局部的异常点、线仍然得到保存、在光滑的同时尽量保持原有的数值特征  相似文献