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121.
Quantitative analysis of the response of ecosystem health to rural land use change is required to comprehend the human-nature coupling mechanism and to explore the process of global environmental change, which can interpret the ecological effects of regional land use and land cover change comprehensively. However, the existing regional ecosystem health assessment largely ignored either the internal connection of ecosystem health to land use patterns or the internal representation of ecosystem services to ecosystem health. Using Lijiang City of China as a study area, the average normalized difference vegetation index (NDVI), landscape metrics, and ecosystem elasticity coefficient based on different land use types were used as quantitative indicators. Then the coefficient of spatial neighboring effect was introduced to characterize the adjacency effect on ecosystem services, and to generate the index of integrated ecosystem health. The results showed the change of land use was close to 30% at county level from 1986 to 2006, and forest land was the primary land use type. With respect to the declining physical health of ecosystems in all the four counties, the integrated health experienced a slight increase in Lijiang County. The vast majority of towns’ ecosystem physical health and integrated health declined, while more than 70% of towns did not change distinctly. Ecosystem physical health had distinct influence on the integrated ecosystem health, and ecosystem vitality was the main factor affecting the condition of physical health. Emphasized in the interconnection of pattern and process, this study provided an ecosystem health approach to assessing the integrated ecological effects of regional land use change.  相似文献   
122.
Statistical modelling of biological survey data in relation to remotely mapped environmental variables is a powerful technique for making more effective use of sparse data in regional conservation planning. Application of such modelling to planning in the northeast New South Wales (NSW) region of Australia represents one of the most extensive and longest running case studies of this approach anywhere in the world. Since the early 1980s, statistical modelling has been used to extrapolate distributions of over 2300 species of plants and animals, and a wide variety of higher-level communities and assemblages. These modelled distributions have played a pivotal role in a series of major land-use planning processes, culminating in extensive additions to the region's protected area system. This paper provides an overview of the analytical methodology used to model distributions of individual species in northeast NSW, including approaches to: (1) developing a basic integrated statistical and geographical information system (GIS) framework to facilitate automated fitting and extrapolation of species models; (2) extending this basic approach to incorporate consideration of spatial autocorrelation, land-cover mapping and expert knowledge; and (3) evaluating the performance of species modelling, both in terms of predictive accuracy and in terms of the effectiveness with which such models function as general surrogates for biodiversity.  相似文献   
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124.
本文研究了我国东南沿海七省中15种土类60科植物根区278份土样中908个种次AM真菌的地域分布规律。本区土壤区带和气候区域的分带基本一致,共分为五个土壤气候带。AM真菌5个属中球囊霉属在所有区带均为优势属,其出现率由北至南稍呈下降趋势;硬囊霉属则与之相反,由北向南总体上呈上升趋势;无梗囊霉属、巨囊霉属和盾巨囊霉属无明显地域规律。AM真菌某些种也有不同的分布规律。  相似文献   
125.
基于甘肃产区党参(Codonopsis pilosula(Franch.)Nannf.)中4种代表性组分(党参炔苷、苍术内酯Ⅲ、多糖和醇溶性浸出物)的含量变化与相应地域气候因子的分析, 探明甘肃境内区域条件、气候因子对党参化学成分的影响及关联性.运用高效液相色谱法测定党参中这4种化学成分含量, 分析区域性、年-季-月不...  相似文献   
126.
我国自然保护区地区分布特征及影响因素   总被引:5,自引:0,他引:5  
闫颜  王智  高军  徐网谷  蒋明康 《生态学报》2010,30(18):5091-5097
自然保护区的建立与发展受自然和社会经济条件等诸多因素的影响,目前我国自然保护区的地区分布差异极大,为寻找影响我国自然保护区的地区分布特征及影响因素,采用主成分分析法(PCA)和回归分析法对影响我国自然保护区地区分布特征的因素进行了提取。结果表明,我国自然保护区的地区分布主要受城市发展状况综合因子、资源禀赋综合因子和农村发展状况综合因子的影响,农村发展状况对我国自然保护区数量分布的影响达到显著水平,而城市发展状况和资源禀赋对自然保护区面积和覆盖率的影响达到显著水平,据此对我国自然保护区发展趋势做出预测,并提出相关对策建议。  相似文献   
127.
Summary We undertook a literature review of the impacts of horse riding in conservation areas, and used it to guide management of horse riding in Canberra Nature Park (CNP), a large, fragmented semi‐natural park in and around the city of Canberra in the Australian Capital Territory. The literature review established that, because of their relatively large weight and small area in contact with the ground, horses have a relatively high potential for doing environmental damage. Impacts tend to be generally lowest for hikers, followed by motorcycles, horses and four‐wheeled vehicles. One study showed horse traffic caused more damage on established trails than motorcycles, off‐road bicycles or hikers. Most published studies of horse‐riding impacts in Australia have been conducted in alpine and subalpine environments, and in temperate woodlands and forests on sandstone near Sydney. They have shown that impacts are generally highest in previously untracked areas. Impacts on established trails are generally most marked on sections of trail that are wet, boggy or steep, and on unplanned and unmaintained trails. Impacts are lowest on constructed and maintained trails. Trail proliferation, associated with avoidance of untrafficable sections and short‐cutting, can be a major problem. Horses also have potential to spread weeds, because pastures and dried stock feeds contain large numbers of weed seeds that retain high levels of viability in horse manure. The risk of weed establishment is highest when manure is deposited in disturbed, damp sites, particularly when riding off‐track. Much less weed establishment is apparent when horse riders remain on‐track. Horse riding is a popular activity, but one that is relatively expensive to provide for, and one that may reduce opportunities for lower‐impact recreational park users. For all these reasons it appears socially equitable that provision is made for lower numbers of horse riders compared to numbers of park users involved in lower impact, more passive, recreational activities. We conclude by describing how this information was used to develop principles to guide management of horse riding and assess risk at individual sites in Canberra Nature Park.  相似文献   
128.
The synchrony of Siberian lemming (Lemmus sibiricus L.) population dynamics was investigated during a ship-borne expedition along the Palaearctic tundra coast in the summer of 1994. On 12 sites along the coast from the Kola Peninsula to Wrangel Island, relative densities of lemmings were recorded using a standardised snap-trapping programme. The phase position of the lemming cycle in each of the studied populations was determined based on current density estimates, signs of previous density and the age profile of each population (ageing based on eye lens mass). In addition, dendrochronological methods were used to determine when the last peak in the density of microtine populations occurred at each site. The examined lemming populations were in different phases of the lemming cycle. Some populations were in the peak phase, as indicated by high current densities, an age profile in which older individuals were well represented, and signs of high previous density (abundant old lemming faeces). Other populations were in the decline phase, as reflected in a moderate current density, a predominance of older individuals and signs of high previous density. Populations in the low phase had an extremely low current density and showed signs of high previous density, while populations in the increase phase had a moderate current density, a predominance of younger individuals and showed signs of low previous density. The results of phase determinations based on dendrochronological methods support the findings based on lemming demography. Recent Russian studies carried out on some of the sites also agreed with our phase determination results. Thus, on a regional scale (across the whole Palaearctic tundra), the population dynamics of Siberian lemmings can be considered asynchronous. However, sites situated adjacent to each other were often phase synchronous, suggesting a more fine-grained pattern of dynamics with synchrony over distances as long as 1000 km or so, e.g. the Yamal and Taymyr Peninsulas. Received: 19 August 1998 / Accepted: 1 March 1999  相似文献   
129.
Energy-Metabolising Enzymes in Brain Regions of Adult and Aging Rats   总被引:3,自引:5,他引:3  
Abstract: The regional enzyme activities of glucose metabolism in the rat brain were investigated. Hexokinase (EC 2.7.1.1) and pyruvate dehydrogenase (EC 1.2.4.1), key enzymes for glucose metabolism, showed no changes in activity in all the regions studied of the aging brain as compared with the adult brain. However, the activity of d -3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) is low throughout the adult brain and, in contrast with hexokinase and pyruvate dehydrogenase, its activity decreases significantly during aging. Other enzymes that showed significant decreases during aging are aldolase (EC 4.1.2.13), lactate dehydrogenase (EC 1.1.1.27), citrate synthase (EC 4.1.3.7), and NAD+-linked isocitrate dehydrogenase (EC 1.1.1.41). The catabolic enzyme in cholinergic metabolism, acetylcholinesterase (EC 3.1.1.7), selected as an example of a non-energy-metabolising enzyme, also showed significant decreases in all regions of the brain in aging, although its highest activity remained in the striatum. These results are discussed with respect to the energy metabolism in various brain regions and their status with aging.  相似文献   
130.
作物区域试验点区辨力估算方法的比较研究   总被引:17,自引:0,他引:17  
对三种估算作物区域试验点区辨力方法(变异系数指标法、回归系数指标法和AMMI模型Dj值法)进行了比较研究,研究表明,三种方法的结论总体上相近,但AMMI模型Dj值法相对较科学准确。  相似文献   
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