The role of landuse and natural determinants for grassland vegetation composition in the Swiss Alps

The Alps provide a high habitat diversity for plant species, structured by broad- and fine-scale abiotic site conditions. In man-made grasslands, vegetation composition is additionally affected by the type of landuse. We recorded vegetation composition in 216 parcels of grassland in 12 municipalities representing an area of 170 x 70 km in the south-eastern part of the Swiss Alps. Each parcel was characterized by a combination of altitudinal level (valley, intermediate, alp). traditional landuse (mown. grazed), current management (mown, grazed, abandoned). and Fertilization (unfertilized, fertilized). For each parcel we also assessed the abiotic factors aspect, slope, pH value, and geographic coordinates, and for each municipality annual precipitation and its cultural tradition. We analysed vegetation composition using (i) variation partitioning in RDA. (ii) cover of graminoids. non-legume forbs, and legumes, and (iii) dominance and frequency of species. Species composition was determined by, in decreasing order of variation explained. landuse, broad-scale abiotic factors, fine-scale abiotic factors. and cultural tradition. Current socio-economically motivated landuse changes, such as grazing of unfertilized former meadows or their abandonment, strongly affect vegetation composition. In our study, the frequency of characteristic meadow species was significantly smaller in grazed and even smaller in abandoned parcels than in still mown ones, suggesting less severe consequences of grazing for vegetation composition than of abandonment. Therefore. low-intensity grazing and mowing every few years should be considered valuable conservation alternatives to abandonment. Furthermore. because each landuse type was characterized by different species. a high variety of landuse types should be promoted to preserve plant species diversity in Alpine grasslands. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

Mapping of shallow coastal groundwaters, their hydrology and environmental geochemistry : Pumicestone catchment, Southeast Queensland

Blooms of the toxic cyanobacterium majuscula Lyngbya in the coastal waters of southeast Queensland have caused adverse impacts on both environmental health and human health, and on local economies such as fishing and tourism. A number of studies have confirmed that the main limiting nutrients (“nutrients of concern”) that contribute to these blooms area Fe, DOC, N, P and also pH. This study is conducted to establish the distribution of these parameters in a typical southeast Queensland coastal setting. The study maps the geochemistry of shallow groundwater in the mainland Pumicestone catchment with an emphasis on the nutrients of concern to understand how these nutrients relate to aquifer materials, landuse and anthropogenic activities. The results of the study form a GIS information layer which will be incorporated into a larger GIS model being produced by Queensland Department of Environment and Resource Management (DERM) to support landuse management to avoid/minimize blooms of Lyngbya in Moreton Bay, southeast Queensland, and other similar settings. A total of 38 boreholes were established in the mainland Pumicestone region and four sampling rounds of groundwater carried out in both dry and wet conditions. These groundwater samples were measured in the field for physico-chemical parameters, and in the laboratory analyses for the nutrients of concern, and other major and minor ions. Aquifer materials were confirmed using the Geological Survey of Queensland digital geology map, and geomaterials were assigned to seven categories which are A (sands), B (silts, sandy silts), C (estuarine mud, silts), D (humid soils), E (alluvium), F (sandstone) and G (other bedrock). The results of the water chemistry were examined by use of the software package AquaChem/AqQA, and divided into six groundwater groups, based on groundwater chemical types and location of boreholes. The type of aquifer material and location, and proximity to waterways was found to be important because they affected physico-chemical properties and concentrations of nutrients of concern and dissolved ions. The analytical results showed that iron concentrations of shallow groundwaters were high due to acid sulfate soils, and also mud and silt, but were lower in sand materials. DOC concentrations of these shallow groundwaters in the sand material were high probably due to rapid infiltration. In addition, DOC concentrations in some boreholes were high because they were installed in organic rich wetlands. The pH values of boreholes were from acidic to near neutral; some boreholes with pH values were low (< 4), showing acid sulfate soils in these boreholes. Concentrations of total nitrogen and total phosphorus of groundwaters were generally low, and the main causes of elevated concentrations of total nitrogen and total phosphorus are largely due to animal and human wastes and tend to be found in localized source areas. Comparison of the relative percentage of nitrogen species (NH3/NH4< Org-N, NO3-N and NO2-N) demonstrated that they could be related to sources such as animal waste, residential and agricultural fertilizers, forest and vegetation, mixed residents and farms, and variable setting and vegetation covers. Total concentrations of dissolved ions in sampling round 3 (dry period) were higher than those in sampling round 2 (wet period) due to both evaporation of groundwater in the dry period and the dilution of rainfall in the wet period. This showed that the highest concentrations of nutrients of concern were due to acid sulfate soils, aquifer materials, landuse and anthropogenic activities and were typically in aquifer materials of E (alluvium) and C (estuarine muds) and locations of Burpengary, Caboolture, and Glass Mountain catchments.

A method for mapping the distribution and density of rabbits and other vertebrate pests in Australia

The European wild rabbit has been considered Australia’s worst vertebrate pest and yet little effort appears to have gone into producing maps of rabbit distribution and density. Mapping the distribution and density of pests is an important step in effective management. A map is essential for estimating the extent of damage caused and for efficiently planning and monitoring the success of pest control operations. This paper describes the use of soil type and point data to prepare a map showing the distribution and density of rabbits in Australia. The potential for the method to be used for mapping other vertebrate pests is explored. The approach used to prepare the map is based on that used for rabbits in Queensland (Berman et al. 1998). An index of rabbit density was determined using the number of Spanish rabbit fleas released per square kilometre for each Soil Map Unit (Atlas of Australian Soils). Spanish rabbit fleas were released into active rabbit warrens at 1606 sites in the early 1990s as an additional vector for myxoma virus and the locations of the releases were recorded using a Global Positioning System (GPS). Releases were predominantly in arid areas but some fleas were released in south east Queensland and the New England Tablelands of New South Wales. The map produced appears to reflect well the distribution and density of rabbits, at least in the areas where Spanish fleas were released. Rabbit pellet counts conducted in 2007 at 54 sites across an area of south east South Australia, south eastern Queensland, and parts of New South Wales (New England Tablelands and south west) in soil Map Units where Spanish fleas were released, provided a preliminary means to ground truth the map. There was a good relationship between mean pellet count score and the index of abundance for soil Map Units. Rabbit pellet counts may allow extension of the map into other parts of Australia where there were no Spanish rabbit fleas released and where there may be no other consistent information on rabbit location and density. The recent Equine Influenza outbreak provided a further test of the value of this mapping method. The distribution and density of domestic horses were mapped to provide estimates of the number of horses in various regions. These estimates were close to the actual numbers of horses subsequently determined from vaccination records and registrations. The soil Map Units are not simply soil types they contain information on landuse and vegetation and the soil classification is relatively localised. These properties make this mapping method useful, not only for rabbits, but also for other species that are not so dependent on soil type for survival.

Spatial Variation of Physico-Chemical and hydrological Parameters with land-use in Venkatapura Catchment,Karnataka

Social, economic and political development of a region is dependent on the health and quantity of the natural resources. Integrated approaches in the management of natural resources would ensure sustainability, which demands inventorying, mapping and monitoring of resources considering all components of an ecosystem. The monitoring of hydrological and catchment landscape of river resources have a vital role in the conservation and management of aquatic resources. This paper presents a case study Venkatapura river basin in Uttara Kannada district of Karnataka State, India based on stream hydrology and landuse analyses. The results revealed variations in dissolved oxygen and free carbon dioxide according to the flow nature of the water, and increased amount of phosphates and coliform contamination in streams closer to anthropogenic activities.

Socio-cultural protection of endemic trees in humanised landscape

Culturally protected forest patches or sacred groves have been the integral part of many traditional societies. This age old tradition is a classic instance of community driven nature conservation sheltering native biodiversity and supporting various ecosystem functions particularly hydrology. The current work in Central Western Ghats of Karnataka, India, highlights that even small sacred groves amidst humanised landscapes serve as tiny islands of biodiversity, especially of rare and endemic species. Temporal analysis of landuse dynamics reveals the changing pattern of the studied landscape. There is fast reduction of forest cover (15.14-11.02 %) in last 20 years to meet up the demand of agricultural land and plantation programs. A thorough survey and assessment of woody endemic species distribution in the 25 km(2) study area documented presence of 19 endemic species. The distribution of these species is highly skewed towards the culturally protected patches in comparison to other land use elements. It is found that, among the 19 woody endemic species, those with greater ecological amplitude are widely distributed in the studied landscape in groves as well as other land use forms whereas, natural population of the sensitive endemics are very much restricted in the sacred grove fragments. The recent degradation in the sacred grove system is perhaps, due to weakening of traditional belief systems and associated laxity in grove protection leading to biotic disturbances. Revitalisation of traditional practices related to conservation of sacred groves can go a long way in strengthening natural ecological systems of fragile humid tropical landscape.

全球变化不绿洲的演化趋势研究-以塔里木盆地北部渭干河绿洲为例

本文以全球变化对绿洲水文循环影响为主线，分析了地处干旱区的绿洲在全球变化下的演变趋势。以塔里木盆地北部渭干河绿洲为例，探讨了其水量平衡、非灌溉土壤积盐特性、隐域性盐化草甸植被NPP，以及绿洲土地利用／覆被变化对全球变化的响应。从不同时间尺度上分析了全球变化的两大驱动因子，气候变化和人类活动对绿洲演化的影响。运用系统动力学模型模拟了未来30年绿洲土地覆被变化在上述两驱动因子的作用下的动态演变过程。其主要结论如下： 1、从生态学的角度，绿洲可定义为：存在于干旱、半干旱区的依赖于水源而生存的隐域性绿色景观．地质时期，绿洲的演化由气候等自然因子起决定作用;人类历史时期，在气候等自然因素的大背景下，人类活动对绿洲演变的作用越来越大;近百年来，绿洲的演变则主要受人为活动干扰。 2、在不改变绿洲现有土地利用格局和水资源利用率的情况下，当年平均气温升高2.5℃，无论降水增加200%或不增加，绿洲的水资源量都将出现负平衡，全球变化将使绿洲面临更为严重的水资源短缺。 3、绿洲自然土壤0-5 0cm土层积盐速率对全球变化的响应程度依地下水埋深的大小而有所差异。地下水埋深较小，积盐速率随温度的升高增加较明显;地下水埋深较大时，积盐速率变化不明显。当地下水埋深>2m，地表积盐速率不再随气候变化而变化．地下水埋深h=2m为渭干河绿洲非灌溉土壤地表积盐速率对全球变化响应的临界深度。 4、根据绿洲地下水埋深与植被NPP的相关关系，推导出了估算盐化草甸植被NPP的模型： NPP=-O. 991+0. 0005Eo (h-0. 25h^2+0. 021h^3) +5. 276EXP (-0. 651h) 并分别估算了当前及全球变化下的NPP值。盐化草甸植被NPP随地下水埋深的增加呈指数下降。全球变化下，地下水埋深较大时，NPP的增加较明显;地下水埋深较小时，NPP的增加不明显。 5、灵敏度分析表明：NPP对地下水埋深h的变化比对地下水矿化度变化为更敏感。h=3. 3m为渭干河绿洲盐化草甸植被的胁迫深度。 6、系统动力学模型模拟表明，渭干河绿洲耕地面积的增减受水资源利用率和人口数量变化的制约。全球变化下，由于水文状况的改变，未来30年将导致绿洲耕地面积增幅下降4. 5-5.1%。绿洲水文状况和人口数量变化是决定土地利用格局变化的关键驱动因素。 7、绿洲灌溉土地的优化模式为，耕地：林地：改良草地=70: 23:7;种植业（耕地）内部的比例为，粮食作物：经济作物：人工草地=46: 31: 23。

鄂尔多斯植物遥感光谱及植被分布特征

本研究通过对鄂尔多斯（主要为毛乌素地区）植物遥感光谱和土壤结皮光谱的测定，通过专题资料搜集、野外踏查、植被样方调查和室内盆栽试验和实验室分析等工作，利用遥感和地理信息系统技术，测定了研究区主要植物光谱和土壤结皮光谱，建立了研究区生态环境本底数据库，在以上的基础上，进行了3方面的详细研究： （1） 通过野外样方调查，野外和室内培养的生物结皮的地面高光谱测定和野外典型地物（鄂尔多斯地区优势高等植物种和沙地土壤）的高光谱测定。采用人工模拟降雨，从苔藓休眠-正常代谢-休眠过程中，研究苔藓土壤结皮的光谱变化，得出苔藓结皮在夏季的生命活动期（正常代谢）的光谱曲线具有高等植物光谱曲线特征;不同地物的NDVI在降水前后变化：苔藓结皮NDVI的变化为0.3-0.35左右，藻类结皮变化为0.15左右，100%盖度的油蒿变化约为0.03左右，而土壤物理结皮的NDVI变化为0.06-0.08左右，可见降水对结皮的归一化植被指数的影响较土壤和高等植被大的多，对苔藓结皮的影响尤其显著。 通过线性模型研究了生物结皮对区域植被遥感解译的影响：模拟得出调查区域（11km样线）由于干湿结皮的变换， NDVI值平均变化0.03， 苔藓湿时的NDVI较苔藓干时相对提高9.3%。可见在研究区，由于苔藓结皮等土壤结皮的存在和干旱半干旱区降雨的不稳定性，必然造成该区域短时间内NDVI的不稳定性。研究结果可为如何结合苔藓结皮的高光谱特征及其变化规律选择和研究合适的生物结皮（苔藓）遥感解译方法提供借鉴。 （2）通过对1980S,1990s,2000s三个时期遥感图像解译，分析了毛乌素沙地沙漠化过程及其驱动机制，认为毛乌素沙地近20年来沙漠化程度有所减轻，植被覆盖有所增加。气候因素和人为因素是导致植被覆盖增加的决定因素，通过多元回归分析确定降水和温度是影响毛乌素沙地植被变化的关键气候因子，并建立了相应的回归方程;人为因素的影响表现在20年来农田和林地的大面积增加。 （3）在建立研究区生态环境本底数据库的基础上，利用遥感解译结果和地理信息系统的空间分析功能，分析了气候因素、地质水文因素、地形和地貌等对植被分布的影响，得出在不同尺度上，影响植被分布的关键因素不同。在鄂尔多斯研究区，区域年降水量对全区的植被分布有着重要影响，尽管地质水文条件的不同也影响了小区域的植被分布。在毛乌素沙地区，在宏观尺度上（旗县），植被分布与其所处的海拔高度关系不明显，在小尺度上，植被分布表现出趋向于相对低海拔分布;小尺度研究中发现，植被分布受地形和基质岩性的组合的综合影响。

东北3省人类活动与水土流失关系的演进

受人类对土地过度垦殖及不合理耕作利用的影响,水土流失正在成为制约我国东北地区耕地可持续利用和粮食生产的主要因素。在对历史资料甄别与整理的基础上,分析近代以来东北3省区人口、土地利用变化及其与水土流失关系的演变。结果表明:到20世纪中期,东北地区人口压力达到60~70人/km2,伴随着生活方式的转变,机械化技术的应用,林草湿地被垦殖,森林覆盖率降到30%,垦殖率达30%,使区域性水土流失问题日益严重。

黄土沟壑区小流域土壤pH值的空间分布及条件模拟

土壤pH值是影响土壤养分有效性和化学物质在土壤中行为的主要因素,研究土壤pH值的空间分布特征对于土壤养分管理和土壤污染预测具有重要意义。该文用地统计学方法研究了环境因素复杂的黄土高原小流域土壤pH值空间分布特征。结果表明,黄土沟壑区小流域土壤pH值具有球形—指数套合模型的空间结构特征,其空间异质性主要来源于流域内土地利用和土壤侵蚀等随机因素。与有机质协同的Kriging法能较好地对土壤pH值进行估值,其估值范围小于实测数据,估值误差来源于复杂的环境因素。序贯高斯条件模拟的土壤pH值范围与实测数据接近,模拟的平均值低于实测数据,模拟误差来源于模拟过程中独特的Kriging算法及高斯特性。

陕北黄土丘陵沟壑区城郊农村土地利用变化定量分析

以典型黄土丘陵沟壑区——延安市赵庄村为例,选取土地利用动态度、土地利用趋势状态指数、土地利用景观指数等指标,对村庄尺度上的土地利用变化进行了定量分析。结果表明,6 a来,研究区土地利用发生了较大的变化,主要以耕地的减少和未利用土地的增加等变化为主;未利用土地、居住及建设用地、林地、灌草地以不同程度增加,其动态度大小依次为43.92%,15.35%,0.33%,0.17%;而耕地、果园、水域则以不同程度减小,动态度大小依次为7.45%,3.79%,0.20%;耕地、果园、水域呈"落势"状态,而未利用土地、居住及建设用地、林地、灌草地呈"涨势",朝着规模增大的趋势发展;斑块数与斑块密度增加,优势度指数与偏离度指数减小,多样性指数、均匀度指数和破碎度指数都有不同程度的增大。