石臼湖湿地生态系统健康评价

湿地是地球上水陆相互作用形成的独特生态系统,对湿地生态系统健康评价,将为生态系统健康诊断和生态修复提供决策依据。充分考虑石臼湖湿地的实际情况,从湿地生态特征,功能整合性和社会经济环境等三方面共选取24项评价指标,建立评价指标体系;分别对石臼湖湿地的生态特征(湿地土壤、植被、水环境质量、生物多样性等)、生态功能(物质生产与生物多样性维持功能、水调节及水质净化功能等)进行了逐项具体分析与评价;然后运用模糊综合评价法及对数模型分别对石臼湖湿地生态系统健康状况进行了综合分析,并对两种评价方法进行了比较分析。最后,在评价分析的基础上,针对石臼湖湿地生态系统存在的问题提出了湿地恢复的对策及恢复方案。     

沼泽湿地生态系统氮素循环研究综述

沼泽湿地是湿地生态系统的重要组成部分,在我国天然湿地面积中占有很大比重,作为氮素的源、汇和转换器,其结构和功能对生态系统氮素循环具有显著影响。本文从沼泽湿地氮素的存在形式、输入与固定、迁移转化及影响因素等方面综述了沼泽湿地氮素循环的过程,并对氮素循环过程造成的生态环境效应进行了分析,最后对沼泽湿地氮循环的进一步深化研究进行了展望。     

中国滨海湿地及其生态系统服务功能研究概述

滨海湿地是海陆交界的生态过渡带,具有特殊的水文、植被、土壤特征。滨海湿地在我国滨海的9个省、2个直辖市、2个特别行政区均有分布。第二次全国湿地资源调查结果显示,全国滨海湿地面积579.59万hm2,占全国湿地面积的12.42%。由于人为开垦与改造、污染物排放、泥沙淤积和水资源不合理利用等原因,中国滨海湿地生态系统服务功能面临诸多挑战。文章从滨海湿地的科学定义及分类入手,分析了现有滨海湿地生态系统服务功能评价方法。从静态评价和动态评价2方面分别阐述了滨海湿地生态系统服务功能的价值评估。针对现有滨海湿地生态系统服务功能研究中存在的问题,提出了今后应从构建滨海湿地生态系统服务功能评估体系、滨海湿地生态特征与生态系统服务功能内在机制研究、滨海湿地生态系统服务功能评估重复性计算、制图与管理等方面进行研究。     

湿地生态系统管理:热点领域与研究方法

湿地生态系统管理以湿地生态系统功能和产品的长期可持续为核心目标,强调基于生态系统完整性的湿地保护和修复,是人类应对湿地退化的重要工具。通过梳理湿地生态系统管理相关研究,文中对其热点领域和方法采用文献列举方式进行分析,概述当前的研究热点,包括湿地生态系统评价、湿地生态系统时空演化及驱动因素、湿地水文过程调控、湿地保护修复的策略与规划、湿地生态系统服务及其权衡与协同、湿地利益相关者需求与协调、湿地综合生态系统管理等;归纳了主要研究方法,包括情景分析法,统计学、数学分析法,模型模拟法,社会、经济协同分析法,统一框架综合决策法等;指出未来研究可能向跨学科交叉与融合持续深化,湿地生态系统服务测量、评价和价值实现,多尺度研究的协同,案例研究进一步丰富和接续等方向发展。     

森林土壤动物生态功能研究进展

森林土壤动物是森林土壤生态系统中不可分割的重要组成部分,对森林土壤生态系统的物质循环和能量流动起着重要作用。文中综述了近10年森林土壤动物生态功能的相关研究进展,包括森林土壤动物对土壤理化性质、微生物、植物的影响以及外来土壤动物入侵对土壤生态系统的影响等;展望了我国森林土壤动物的未来研究方向,未来研究应多关注森林土壤动物生态功能的作用机制、森林土壤动物对全球变化的响应、外来土壤动物入侵对森林生态系统的影响、森林土壤动物种类的研究范围以及新技术的应用,以期为我国森林土壤动物生态功能、土壤动物与生态系统、可持续利用土壤动物等领域研究提供科学参考。     

土壤微生物多样性及其影响因素

土壤微生物多样性是指土壤微生物在自然界中的种类多样性,包括功能多样性、遗传多样性、物种多样性。通过对已有的研究成果进行总结归纳,综述了影响土壤微生物多样性的因素,围绕土壤水分、土壤温度、土壤pH值、土壤覆盖植被类型、种植制度、施肥等方面对土壤微生物多样性影响因素进行了探讨。由于土壤微生物多样性对土壤生态系统以及农业生产有显著影响,因此,对土壤微生物多样性的研究至关重要。为此,主要从土壤微生物多样性出发,分析了影响土壤微生物多样性的因素。     

溱湖湿地现状及修复措施分析

江苏省姜堰市溱湖湿地具有水分调节、净化水源、提供动物栖息地、调节局部小气候等多种生态功能。在阐述了该区湿地资源现状的基础上,分析湿地面临天然湿地面积减少、生境丧失、水质下降、林木虫害、控期空气污染、试验区人为干扰严重、环境监测滞后等6个问题,并对溱湖湿地公园已完成的水利、生物和旅游等3大重点工程对湿地生态系统的影响进行综合分析,最后针对溱湖湿地生态系统存在的问题和已完成的3大重点工程的负面影响,提出了以遵循修复为先与适度开发原则,加大流域管理原则,维持自我设计和自然恢复原则,坚持恢复湿地的生态完整性、自然结构和自然功能原则,遵循水环境治理优先性和群落和种稀缺性优先保育原则加强溱湖湿地修复和开发的建议,以期对湿地的保护提供借鉴。     

洱海湿地生态系统及其保护措施探讨

分析洱海湖泊湿地资源与功能价值;从水利建设、围湖造田、旅游业、农业面源污染、渔业生产、工矿企业等方面探讨了人类活动对湿地生态系统的影响;全方位地提出了保护洱海湖泊湿地资源与环境的对策和建议。     

黄河中游(龙门—汾河入黄口)土壤含盐量与湿地植物多样性的相关关系研究

以黄河中游(龙门—汾河入黄口)河漫滩湿地生态系统为研究对象,采用系统取样法设置了13个样地,并对各样地内土壤环境因子进行了调查。同时引用课题组对以上样地内植物的α多样性和功能多样性的测度结果,分析了各个多样性指数和土壤因子之间的相关关系,并用回归分析的方法进行验证。结果表明:(1)黄河中游湿地植物的物种丰富度受到土壤pH值和土壤含盐量的影响,物种均匀度与各土壤因子之间不存在显著相关性;(2)黄河中游湿地植物的功能丰富度和功能离散度受到土壤pH值、土壤含盐量的影响,功能均匀度与各土壤因子之间均不存在显著相关性。     

国外湿地公园保护与管理研究综述

建设湿地公园是保护和利用湿地资源的重要手段,梳理国外相关研究成果能够指导我国湿地公园研究与实践。文中对20世纪90年代以来国外相关文献进行综述,探究国外对湿地公园生态系统三个子系统保护与管理的研究现状与热点。对于湿地生态系统恢复,国外研究由整体生境保护向各个生态要素的管理与利用转变;对于生态游憩系统引导,国外研究主要探讨大众湿地审美偏好与湿地生态功能间的内在关系;对于园外影响系统监测,国外研究聚焦于3S技术与数字建模技术对湿地影响因素的模拟与评估。     

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.