贵州3处保护区生物廊道景观格局与连通性浅析

以黔东武陵山至苗岭山系间的梵净山国家级自然保护区、佛顶山省级自然保护区及雷公山国家级自然保护区为研究对象,选定生物廊道宽度为2 km,以3个自然保护区现有的边界为基础,向外扩展平均约50 km为缓冲区并彼此相连形成可供成为生物廊道的互通区域,对这一区域景观特征及廊道连通性进行研究。结果表明:1三者景观多样性指数(SHDI)为0.97,景观斑块分布较均匀;2在景观尺度水平上,三者间不同类型斑块与不同因子斑块结合度(COHESION)均较高,达99以上,表明三者间连通性良好;3根据连通性路径分析结果,佛顶山北段至梵净山区域连通性良好,连通因子占廊道面积达88.90%,佛顶山南段至雷公山区域,连通因子占86.12%,生物廊道连通因子主要为林地构成,阻隔因子主要为耕地及建设用地。研究结果揭示了3个保护区内及其之间生物廊道的景观斑块特征与生物物种扩散的景观连通性,可为构建科学有效的生物廊道与区域自然保护区群提供参考。     

基于景观连通性的森林保护与恢复优先区域识别——以丁青县为例

保护和提升景观连通性被广泛认为是森林景观管理的主要目标之一。基于景观连通性原理,采用连通概率及斑块重要值,对研究区森林斑块重要性进行分析,确定现有森林斑块的保护优先级和潜在森林斑块的恢复优先级。结果显示：森林斑块重要值总体上与距离阈值呈正相关,且小斑块森林重要性随着距离阈值的增加而逐渐提高;森林斑块重要性被划分为“非常高”“高”“中等”“低”“非常低”5个等级,其中具有“非常高”和“高”等级的3个现有森林斑块和4个潜在森林斑块对于保障和提高森林连通性起重要作用,应优先加强对这些重点斑块的保护与恢复力度;对于扩散距离较大的林栖物种,应因地制宜保护和恢复“中等”“低”“非常低”等级的现有森林斑块和潜在森林斑块。研究方法能够精准识别重要森林斑块,从而为区域森林保护与恢复规划提供参考。     

北京城市扩展轴上的绿地景观格局梯度分析

应用梯度分析与景观指数相结合的方法,分析了2004年北京城市绿地系统沿东西和南北两条城市扩展轴分布的空间格局。结果表明:城市绿地整体上破碎化程度高,连通性好,边缘效应较强;从城市中心到边缘,绿化覆盖率不随距城市中心远近而变化,小型斑块数量比例、斑块数量、形状指数、破碎度、平均最近邻体距离等指标则表现出明显的梯度变化;影响绿化覆盖率和斑块面积频率分布的主要因素是公园性质大型斑块的分布状况。研究结果说明:在目前城市绿化覆盖率较难提高的情况下,通过应用梯度分析与景观指数相结合的方法对现有绿地空间结构进行分析调整,不仅能优化城市绿地的景观格局,还能更好地发挥出城市绿地缓解环境问题的功能。     

基于空间绩效的城镇绿地生态网络构建——以安徽宣城狸桥为例

根据景观生态学相关理论,不同景观要素组成的空间格局是影响其空间绩效的主要因素之一。在综合分析生态系统服务、景观空间结构、生态敏感性及其累计耗费距离表面水文功能等空间绩效的基础上,分析研究狸桥镇绿地生态网络空间布局。结果表明:研究区生态系统服务价值为37 538万元/a,其空间绩效较优;在其平原地区,建设用地和耕地广布,生态斑块较小且连接度较低,景观呈现破碎化;在中西部山区,生态斑块较大,但对其周边生态服务能力较弱;研究区生态敏感性划分为极度敏感区、高度敏感区、中度敏感区、低度敏感区和非敏感区5个等级,分别占研究区36%、18%、17%、19%和10%;以生态敏感性综合评价值作为费用表面,确定具有一定生态系统服务价值的生态用地作为生态源,进而构建累计耗费距离模型。并通过Arc GIS水文分析,规划了境域潜在生态廊道和生态节点;结合狸桥镇河流、道路及空间特征现状,综合构建了城镇绿地生态网络,为今后城镇生态建设和发展提供科学依据。     

基于遥感和GIS的城市绿地景观格局分析

运用景观生态学原理,借助遥感和GIS技术,选取了绿地景观构成、景观多样性、优势度、廊道密度和分维数等指数,分析了深圳特区城市绿地景观的空间格局。结果表明:整个研究区内的绿地类型以公园绿地和风景名胜区绿地为主,城市绿地廊道主要是道路交通绿地廊道,特区内绿地景观多样性相对丰富,所占比例相对均匀,分维数居于中等水平。     

长沙市多层级绿色基础设施网络构建

绿色基础设施(GI)的网络化构建,是解决城市化进程中生态斑块破碎化的重要举措。文章以长沙市为研究对象,运用形态学空间格局分析(MSPA)识别现状绿色基础设施要素,依据景观连通性对GI网络中心分级;通过景观格局指数评价现状GI网络格局,结合自然、人类活动因素构建生态阻力面;采用最小累积阻力模型(MCR)与重力模型构建连接廊道,并提取生态节点。结果表明：一级网络中心分布于长沙市的西南部、北部;中部生态阻力较大,不利于网络中心的连接,通过多级连接廊道的构建有效地连接GI网络中心;生态节点可提高较长廊道、阻力值较大区域的连通性,从而构建起多层级的GI网络,为城市绿色空间的建设提供参考。     

吕梁市域生物多样性保护的生态安全格局

城市生物多样性保护是食物生产、人类健康和城市安全的必要保障,生态安全格局的构建能够维护自然生态平衡、保持生境稳定性和提高景观连通度,是生物多样性保护的重要空间途径。以吕梁市为例,采用形态学空间格局分析法和景观连通性指数法定量评估生态斑块重要性,辨别生态源地,利用最小累积阻力模型提取生态廊道和战略点,构建市域生物多样性保护的生态安全格局。结果表明:景观格局中核心区、桥接区、孤岛为林地和水域要素主要构成;沿吕梁山脉带状分布的生态源地景观连通性较大,西部生态源地面积较小且斑块重要性相对较低;"两纵,多横"的生态廊道布局和战略点布设,有效提高了市域生态结构的完整性。研究结果可以为市域尺度生物多样性保护规划提供思路和方法。     

面向蓝绿空间网络的青岛市南区绿地布局及绿道选线

为了进一步优化沿海地区的蓝绿空间网络,选取典型滨海山地区域(青岛市南区)为研究对象,提取308处自然资源和173处文化资源的代表性样点,运用ArcGIS空间模型对其绿地空间布局类型、空间分布格局、分布密度进行分析,并运用成本连通性模型确定市南区最低成本路径的优化网络,提出面向蓝绿空间网络连接的复合型游憩绿道选线方法和规划建议。结果表明：青岛市南区绿地空间布局呈凝聚型分布,且形成7个绿地集群;市南区绿地空间分布模式主要为依附型、支撑型、扩散型3类,且具有明显的绿地空间自相关性;识别出1条一级绿道、3条二级绿道、38条三级绿道构成理想的蓝绿空间网络图。研究结果将为识别我国沿海地区资源特征,形成完善的绿色基础设施和蓝色廊道的空间衔接提供参考。     

基于MSPA的福州市绿色基础设施网络构建与优化研究

指出了绿色基础设施网络的建设能够增加景观格局连通度,是应对快速城市化所导致的各类生态问题的重要途径。以福州市为例,在GIS技术的支持下,运用景观格局指数分析、形态学空间分析(MSPA)和景观连通度分析等方法获取研究区域GI源地,运用最小积累阻力模型(MCR)提取潜在廊道,构建并优化了GI网络。结果表明:福州市景观类型整体上较为丰富,以林地为主要用地类型的GI源地间缺乏连接,潜在生态廊道一定程度上增强了连接度,并通过适当增设源地的方法对GI网络进行了优化,改善了廊道过长、空间分布不均等问题,能为后续福州市城市绿地系统规划研究提供一定参考。     

成都市中心城区绿地景观格局时空演化:“城”与“郊”的比较

基于2000年与2018年的遥感数据,采用GIS、RS技术和Fragstats 4.2景观分析软件,研究成都市中心城区绿地景观格局的时空演变特征。结果表明:(1)数量上,2000-2018年,成都市绿地率由12.55%增为29.39%,新增绿地主要由耕地、建设用地转化而来,减少的绿地主要转为了建设用地、耕地;(2)空间布局上,2000-2018年,建设用地由三环向外围扩张,大斑块绿地和大量农田、菜园等生态绿地退到外围郊区,绿地空间分布不均,且主要向外围郊区的东北角和东南角集聚,东北角破碎度高于东南角,南部生态质量优于北部;(3)景观格局上,2018年,由市中心到中心城区边缘,绿地斑块个数增多、斑块破碎度下降、斑块形状指数和聚集度上升,"外围近郊区"景观格局优于"主城区",2000-2018年,二环到三环的斑块形状指数下降。为此本文提出以区域生态本底为基础,在外围郊区设置"禁建区"控制城市蔓延。同时,增加廊道绿地建设,促进"城"与"郊"绿地联系和均衡布局。     

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.