Comparison of traditional wild plant knowledge between aboriginal communities inhabiting arid and forest environments in Patagonia, Argentina     

A. Ladio  M. Lozada  M. Weigandt 《Journal of Arid Environments》2007,69(4):695-715

The Mapuche people have a deeply rooted tradition of wild plant use for their subsistence. In this study we evaluated whether plant selection by the Mapuche is influenced by environmental constraints. Selection patterns of wild plant richness were compared in two Mapuche communities sharing the same traditions and beliefs but inhabiting different environments. Similarities and differences in the use patterns of wild medicinal and edible plants were quantitatively analyzed by using concepts derived from ecological theory. The Cayulef community is settled in the NW Patagonian (herbaceous) steppe while the Curruhuinca community is established near the Andean temperate forest, 100 km away from each other. Free-listing and semi-structured interviews were conducted with 32 families in Cayulef and 39 in Curruhuinca corresponding to 80% and 40% of each population, respectively. Data were analyzed by means of the Jaccard similarity index and statistical tests. The main results of this study showed that the home environment is a determinant factor that influences which plant species are utilized, as is the anthropic environment (with its high exotic species richness) in each community. However, similar patterns were found with respect to plant families, ways of utilization, plant parts and life forms utilized irrespective of where the communities are settled. In addition, in both populations, wild plant richness was significantly higher for medicinal than for edible species. Our results showed that the use of wild plants is primarily based on the utilization of species belonging to the nearest ecological environments that have both therapeutic and dietary functions.  相似文献   

Soil erosion along a long slope in the gentle hilly areas of black soil region in Northeast China     

CUI Ming  CAI Qiangguo  ZHU Axing  FAN Haoming 《地理学报》2007,17(3):375-383

Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on seg-ments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm, Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation, rill cannot happen within the top 50 m, while in a year with large and inten-sive precipitation, rill can be formed starting even at 15 m from the top of the slope.  相似文献   

区域经济一体化的动力机制及组织类型     

赵媛  诸嘉 《世界地理研究》2007,16(3):1-7

区域经济一体化在二战后得到迅速发展，并已成为当今世界经济发展的主要趋势之一。其载体区域经济一体化组织的内容也更加丰富、层次更加多样。从发展的角度看，区域经济一体化是全球范围内市场经济发展到一定阶段的结果，促使其发展的动力机制为“推、拉、压、支”四力驱动和“传统经济利益、非传统收益、政治利益”三大取向。在组织类型上，根据区域经济一体化内容和发展程度的不同分为优惠贸易安排、自由贸易区、关税同盟、共同市场、经济同盟和完全的经济一体化六种类型。  相似文献   

2D magnetic resonance tomography applied to karstic conduit imaging   总被引：1，自引：1，他引：1  

J.-F. Girard  M. Boucher  A. Legchenko  J.-M. Baltassat 《Journal of Applied Geophysics》2007,63(3-4):103-116

Karstic conduits play a crucial role for water supply in many parts of the world. However, the imaging of such targets is generally a difficult task for most geophysical methods. Magnetic Resonance Sounding (MRS) is a geophysical method designed for imaging of water bearing structures. Initially, MRS was developed for characterizing horizontally stratified aquifers. However, when applying a 1D MRS measuring setup to the imaging of 2D–3D targets, the size of which may be much smaller than the loop, the accuracy and the lateral resolution may not be sufficient. We have studied the possibility of simultaneously processing several MRS aligned along a profile to perform a Magnetic Resonance Tomography (MRT). This work emphasizes the gain of resolution for 2D–3D imagery of MRT versus the interpolation of 1D inversion results of MRS along the same profile. Numerical modelling results show that the MRT response is sensitive to the size and location of the 2D target in the subsurface. Sensitivity studies reveal that by using the coincident transmitting/receiving (TX/RX) setup and shifting the loop around the anomaly area, the depth, section and position of a single karstic conduit with a size smaller than the MRS loop size can be resolved. The accuracy of the results depends on the noise level and signal level, the latter parameter being linked to the depth and volume of the karstic conduit and the water content in the limestone matrix. It was shown that when applying MRT to the localization of 2D anomalies such as karstic conduits, the inclination of the geomagnetic field, the orientation of the MRT profile and the angle of crossover of the conduit by the MRT profile must be taken into account. Otherwise additional errors in interpretation should be expected. A 2D inversion scheme was developed and tested. Both numerical and experimental results confirm the efficiency of the developed approach.  相似文献   

高密度电法在电力工程勘测中的应用   总被引：4，自引：0，他引：4  

严文根  方军 《上海国土资源》2002,(1):57-60

该文通过工程实例，分析了高密度电法在电力工程勘测中的应用前景、应用效果及发展方向。  相似文献   

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   

根据构造环境剪应力值水平区分地震和核爆炸   总被引：5，自引：1，他引：5       下载免费PDF全文

陈培善  成瑾  白彤霞 《地震学报》2001,23(3):246-249

根据地震破裂的断裂力学模式，导出了震源参数与地震发生处的构造环境剪应力值t0之间的函数关系．据此，可以大量计算震源处的构造环境剪应力值或背景应力值．若把核爆炸当作地震来计算，发现核爆炸的t0值平均在20MPa左右，明显地高于同震级地震的t0值．其结果可以作为区分地震与核爆炸的依据．   相似文献   

Discrimination between nuclear explosions and earthquakes based on consideration of tectonic ambient shear stress values     

陈培善  成瑾  白彤霞 《地震学报(英文版)》2001,14(3):259-262

IntroductionFor the need of a nuclear test ban treaty, international society must make great efforts to find effective methods for discrimination between earthquake and nuclear explosion. Thereupon, many methods of discrimination of nuclear explosion appeared. But, at present, there is some uncertainty to discriminate middle or small nuclear explosion (Peppin, McEvilly, 1974; Richards, Zarales, 1990). When we study tectonic ambient shear stress field of Southern California, we find that str…  相似文献   

通海地磁台(L=1.03)Pc3地磁脉动的出现率     

韩德胜  高玉芬  张福  P.J.Chi 《地震地磁观测与研究》2001,22(5):16-21

利用通海地磁台(L=1．03)1999年SMALL磁通门磁力仪记录资料，对Pc3脉动出现率的统计结果表明，日出现频次有两个峰值，即清晨06：00-07：00LT(地方时)出现频次最高，午后14：00～15：00LT为次峰值。Pc3脉动月出现频率最高的是4月和12月，其次是8月和9月；最少的是6月和7月。按季节统计结果为春秋季出现频次最高，冬季次之，夏季最低。  相似文献   

Predicting channel patterns   总被引：1，自引：0，他引：1  

John Lewin  Paul A. Brewer   《Geomorphology》2001,40(3-4)

The proposed distinction between meandering and braided river channel patterns, on the basis of bankfull specific stream power and bed material size, is analysed and rejected. Only by using regime-based estimates of channel widths (rather than actual widths) has discrimination been achieved, and it is argued that this procedure is unacceptable.An alternative is to explore the patterning processes underlying the marked pattern scatter on bankfull stream power/bed material size plots. Of the five sets of patterning processes, large-scale bedform development and stability is seen as especially important for meandering and braiding. For gravel-bed rivers, bedforms developed at around or above bankfull stage appear important for pattern generation, with braiding relating to higher excess shear stress and Froude number. There seems to be an upper threshold to both meandering and braiding which is achieved at extreme discharges and steep gradients, as on steep alluvial fans, rather than for the rivers with available flow data here considered. For sand-bed rivers with greater excess shear stress, the equivalent upper plane bed threshold may occur below bankfull, with bed material mobility and bedform modification occurring over a wider range of sub-bankfull discharges. Sand-bed channel margin outlines appear to be less perturbed by bedform effects than gravel bed planforms, and they may have naturally straight or sinuous planforms. Bedform relief may nevertheless lead to some being designated as braided when viewed at low flows.It is concluded that the use of a single-stage stream power measure and bed material size alone is unlikely to achieve meandering/braiding discrimination.  相似文献