四川江油让水河国家湿地公园湿地资源现状及其湿地系统的评价

本文分析了让水河国家湿地公园的湿地类型及面积、湿地生物多样性、湿地景观及文化资源,对湿地公园的湿地资源及湿地系统做出了评价,评价结果为优秀,表明:(1)湿地公园具有完整、良好的生态系统;(2)湿地公园生态系统原始、类型多样;(3)湿地生物多样性资源丰富,具有极高的观赏性和保护价值;(4)人文景观价值很高,历史文化氛围浓厚。     

天池自然保护区湿地的六大功能

天池是中外闻名的风景名胜，同时，作为湿地生态系统，天池自然保护区湿地生态系统不仅为人们提供了丰富的社会和经济效益，更具有极高的生态功能，对维持生态平衡，改善生态环境，保护生物多样性和珍稀物种资源等方面起到了重要的作用。     

浅析城市湿地公园建设问题及对策

湿地是地球水陆系统相互作用形成的独特生态系统,是人类重要的生态环境,也是自然界生物多样性最丰富的生态系统之一.湿地公园的建设和资源保护有助于丰富生物多样性、展示生态系统服务功能以及生态旅游和生态教育的开发建设.因此,要做好湿地资源的保护工作,就要系统地分析湿地公园建设中存在的问题,寻求合理的保护途径,最终实现湿地公园的可持续发展.     

营造可持续发展的湿地景观--浙江富阳鹿山滨江景观规划设计理念

介绍了湿地生态系统的概念及定义。湿地具有丰富的生物多样性,在减缓自然灾害、净化环境、精神文化、教学科研等方面为人类提供了服务,指出湿地生态系统恢复的重要意义,并以浙江富阳鹿山滨江景观规划设计为例,提出了保护和恢复湿地生态系统的手段和湿地生态旅游资源的开发模式。     

论大兴安岭林区湿地资源的保护

内蒙古大兴安岭林区湿地资源较为丰富，保护其独特的生态系统，对林区生态环境建设、社会经济发展及生态系统的恢复都有着十分重要的影响。     

浅谈云南丽江拉市海高原湿地生态旅游开发

云南丽江拉市海湿地省级自然保护区是“中国湿地保护行动计划”173个重要湿地之一，主要以高原湿地、野生动物和湿地植物群落为保护对象，保护区面积6523hm^2。水域、沼泽、草地皆备，是云南省高原湿地保护区中湿地生态系统保存较为完整、湿地植物较为丰富的保护区。在分析保护区丰富的旅游资源等优势与现阶段旅游发展现状的反差基础上，提出了开展宣传、加强湿地保护与管理、加强旅游基础设施建设等今后开发对策。     

云南普洱五湖国家湿地公园现状及保护对策探讨

我国湿地公园发展较快,湿地公园已成为我国湿地保护和合理利用的重要组成部分,也是湿地保护和合理利用的一种新模式。普洱五湖国家公园湿地具有典型的森林——湿地复合生态系统,孕育了丰富多样的生物多样性,为当地生产生活以及澜沧江流域提供了丰富的水资源,也为普洱市社会经济发展提供了重要的物质基础和环境保障。文章对普洱五湖湿地的资源现状、生态系统作了分析并提出五湖受威胁的问题所在,同时,也提出了解决对策和措施,对普洱五湖今后的建设、保护与合理利用具有重要意义。     

怀宁县湿地现状与保护初探

指出了湿地与森林、海洋并称为全球三大生态系统,是具有多种服务功能的宝贵自然资源。从怀宁县湿地资源概况、湿地分布及特点入手,阐述了怀宁县湿地资源丰富,湿地生态功能和价值显著,并提出了采取不同的保护和恢复措施进行适度地开发,尽量做到因地制宜、普遍保护、突出重点等方面的建议。以期为湿地保护工作提供借鉴。     

金寨县湿地与森林资源现状及保护利用

湿地，是地球上生物多样性丰富的、生产力较高的生态系统，也是人类最重要的环境资源之一，我国于1992年加入国际《湿地公约》，每年的2月2日被定为“世界湿地日”，湿地资源越来越受到人们的重视，保护程度也在不断提高。     

珍宝岛国家级自然保护区湿地资源现状与保护对策

珍宝岛自然保护区保存完好的天然湿地生态系统,是我国北方地区最具原始性、典型性和代表性的天然湿地,是东北亚地区鸟类的重要栖息地,具有丰富的生物多样性。文章通过对珍宝湿地资源现状的调查,对自然保护区内的资源现状进行了详细论述,结合实际现状对湿地资源提出了保护对策。     

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.