基于GIS和RS的兰州新区生态安全评价

以兰州新区为例,基于GIS和RS技术,以2004年Landsat7 ETM遥感影像为主要数据源,借助于GIS空间分析功能,并选用熵权法来计算各指标的权重,对兰州新区进行生态安全综合评价。结果表明:兰州新区生态安全分布不均匀,地区生态安全差异明显,生态安全分区的空间分布规律呈现由新区核心区域向新区四周依次增加。建议对生态安全指数较低区域进行生态规划和建设,并对指数较高区域进行生态修复,使其成为兰州新区的天然保障。     

基于ANN的洞庭湖区生态承载力预警研究

生态承载力预警是判定生态系统可持续承载的重要依据。利用状态空间法和人工神经网络模型对洞庭湖区生态承载力进行预警分析,结果表明:(1)景气预警上,洞庭湖区2001~2010生态承载力整体上处于中警状态,反映出湖区生态、资源、环境与社会经济发展的协调性较差,生态系统可持续性较弱。洞庭湖区17个区域单元生态承载力出现了重警、中警和轻警三种状态,2001年、2005年和2010年3个年份的区域差异及变化相当明显。(2)景兆预警上,2015年洞庭湖区生态承载力接近轻警状态,可持续承载能力由弱可持续向可持续转变;相比2010年,17个区域单元的重警和中警比重分别下降了33.3%和18.2%,轻警比重上升了100%,体现了洞庭湖区国民经济和社会发展"十二五"规划纲要和环境保护"十二五"发展规划合理,生态环境保护和修复计划有效,生态调控措施得力。(3)利用BP神经网络模型可以科学地预测预报生态承载力未来发展趋势,判定区域经济、社会和生态的可持续性;模型的应用可靠可行,预警结果可以为区域生态系统的可持续发展提供科学依据。     

洱源西湖湿地生态环境脆弱性评价

指出了湿地生态环境的脆弱性评价能够为区域生态持续发展规划提供建议、指导和科学依据,是当前社会经济发展、城市建设、区域生态环境发展过程中需要关注的重要问题之一。以大理市洱源县西湖湿地为研究区域,从影响湿地生态脆弱性的自然因素和社会经济因素两个方面选取了8个评价指标,利用生态脆弱性指数评价法对洱源西湖湿地的脆弱性进行了评价,针对造成洱源西湖湿地生态环境破坏的几种自然因素和人为因素提出了一些保护建议。     

湖南省森林生态安全预警研究

以湖南省森林生态系统作为研究对象,综合考虑区域特点及发展现状,结合生态安全评价、生态安全预警等理论,借助PSR模型建立了预警体系,分析结果得出:经济、社会、科技教育水平、环境和资源是影响湖南省森林生态系统的主要因素。利用模糊指数评价法,通过最大隶属度原则得到湖南省森林生态安全水平逐年提升的结论并提出了相应的治理措施。     

基于GM(1,1)模型的阜平县土地生态安全预警与分析

基于2012—2017年阜平县土地生态安全的相关统计数据,通过PSR模型构建土地生态安全预警指标体系,采用GM(1,1)灰色系统理论模型对2018—2022年的土地生态安全变化进行预警,结合预警指数及评判标准对2012—2022年的土地生态安全状况做出预警分析,为阜平县的土地生态安全调控提出政策参考。研究结果如下:(1)阜平县土地生态安全综合预警指数从2012年0.336 1(重警)上升到2017年0.555 6(中警),土地生态安全状况不断好转;(2)2012—2017年阜平县土地生态系统的压力层预警指数、状态层预警指数及响应层预警指数均呈上升趋势;(3)2018—2022年土地生态安全预警值分别为0.576 9(中警)、0.626 0(轻警)、0.679 3(轻警)、0.737 1(轻警)、0.799 8(轻警),表明未来5年阜平县土地生态安全的状况将持续改善。     

异龙湖流域生态安全格局构建与评价

高原湖泊是区域经济发展的重要载体，城镇化进程的推进和旅游业的发展对高原湖泊生态环境造成一定影响，高原湖泊流域的开发与其生态保护间的矛盾凸显，亟需开展高原湖泊流域生态安全研究。以异龙湖流域为研究区域，基于土地利用数据和DEM高程数据，运用综合指数法、熵值法和GIS空间分析技术，通过生态安全评价模型(ESI)对异龙湖流域生态安全进行评价，同时结合最小累积阻力模型(MCR)，以源地-廊道-节点的方式构建异龙湖流域生态安全格局。结果表明，异龙湖流域中度安全区域占流域总面积的33.03%，较低安全区域占32.45%，不安全区域占20.36%，高度安全区域占14.16%，平均生态安全指数为2.34，总体处于中度安全状态，流域生态系统健康状况一般；高度安全区域集中分布在异龙湖国家湿地公园；坝心镇的生态安全状况最好，其次为异龙镇，宝秀镇最差。异龙湖流域生态源地总面积为128.45km²，占流域总面积的36.03%，呈现以异龙湖为中心、流域四周集中连片的分布特征，其中异龙湖国家湿地公园在该流域生态安全保护中占主导地位。识别出18个生态节点，并提取出20条生态廊道；根据计算结果将异龙...     

基于GIS的临泽县土地生态适宜性评价

以甘肃省临泽县为研究区域,运用GIS技术,在该县行政区划和自然地理条件基础上,划分土地评价单元,运用特尔菲法对预选评价指标集进行筛选,建立评价指标体系并确定各评价因子的权重值,并通过指数加权求和法计算各评价单元的综合评价值,确立土地生态适宜性分级标准。划分临泽县土地生态适宜性分区,确定划分区域的土地用途,建立临泽县土地利用适宜生态发展的模式,以期为该县生态安全屏障建设提供科学依据。     

基于RS和GIS的江西省区域生态安全动态评价

应用RS和GIS技术,以栅格为评价单元,结合已有生态安全评价和森林生态系统健康评价研究,从生态环境状况、生态系统结构与稳定性、景观结构和外界干扰这4个方面选取指标,构建江西省生态安全评价体系。应用变异系数法、层次分析法确定权重,系统评价分析了江西省2000—2010年时间段内生态安全变化状况。评价结果显示:2000—2010年,江西省生态安全指数从63.0794升至63.2933,区域生态安全指数值较大,处于较安全等级,且整体生态状况有所好转。对江西省11个地级市2000—2010年的生态安全评价结果分析发现:总体上抚州市、景德镇市、吉安市、鹰潭市和宜春市生态安全水平相对较高,而萍乡市、南昌市、新余市、九江市、上饶市以及赣州市的生态安全水平则相对较低。     

侧柏林分质量与生态功能综合评价研究

为科学地进行林业生产活动和制定森林经理方案,选择准确的林分进行质量评价体系是非常重要的。以北京市十三陵林场400多个以侧柏为优势树种的小班作为研究对象,根据2004年和2009年十三陵林场的二类数据,建立模糊综合评价体系和生态功能综合指数评价体系两套评价体系,对林分质量进行评价分析,并对比两种评价体系的差别之处。模糊综合评价体系利用层次分析法和模糊综合评价法,确定各个指标的权重,再划分评价等级,建立隶属度R矩阵并计算,由"最大隶属度"原则判定林场的评价等级,进行森林质量评价;生态功能指数评价体系依据国家林业局制定的中国森林生态功能的指标等级和权重,并根据Y=8∑i=1W_iX_i,K=1/Y算出林地生态功能指数。模糊综合评价体系分析结果显示,2004年与2009年侧柏林的生态功能指数分别是"劣"和"中";生态功能指数评价体系分析结果显示,2004年与2009年的生态功能指数为0.47与0.60。两种不同的评价体系均说明了2009年林分质量较2004年有了很大提升,评价结果具有一致性,说明两种方法都适用于森林质量的评价分析。但从全面性、使用的方便性和精确度等方面比较来看,生态功能综合指数评价体系要优于模糊综合评价体系。     

罗平县万峰山自然保护区拟建科普馆项目对生物多样性影响评价

通过野外调查和查阅文献资料,在罗平县万峰山自然保护区拟建科普馆项目周边区域直线1 000 m范围内开展生物多样性影响评价区考察研究,并对影响区域内景观、群落、物种、主要保护对象、物种安全、社会因素6个指标进行影响评价分析。结果表明,影响评价区内生物多样性影响指数为51.4,对罗平县万峰山自然保护区生物多样性的影响程度为“中低度影响”。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.