大山包越冬黑颈鹤觅食地选择的初步观察

在云南大山包黑颈鹤国家级自然保护区对越冬黑颈鹤(Grusnigricollis)的觅食地选择进行了观测,采用卡方检验和Bonferroni-Z分析法对观测结果进行分析,结果表明:越冬黑颈鹤对草地的利用为负选择,对草甸和农地的利用属于正选择,亚高山沼泽化草甸是越冬黑颈鹤主要选择和利用的生境.     

三江自然保护区丹顶鹤春季觅食生境初步研究

采用样方因子测定法对三江国家级自然保护区丹顶鹤春季觅食生境进行调查研究的结果表明:丹顶鹤春季主要在以苔草、小叶章为主的沼泽湿地中觅食;觅食地植被高度小于40 cm,植被密度低于400株/m2,植被盖度为0～25%,觅食地水深多为5～15 cm,人类干扰距离大于1 500m;人为活动严重影响着丹顶鹤的觅食;春季丹项鹤有在...     

大山包越冬黑颈鹤野外动态监测

大山包黑颈鹤国家级自然保护区位于云南省昭通市昭阳区西部，其主要保护对象是黑颈鹤及其越冬栖息的亚高山沼泽化草旬湿地生态系统。大山包保护区管理局结合越冬期水禽监测开展了大山包保护区越冬黑颈鹤动态监测研究，通过研究掌握了越冬黑颈鹤种群数量、种群结构、生活习性、觅食地等基本情况，对保护黑颈鹤及其越冬栖息的湿地生态环境起到积极的作用。     

流淌在大山包里的敬老情

正"来不过九月九,去不过三月三",这是大山包村民对当地黑颈鹤越冬生活的节令总结。的确,有"鸟类熊猫"之称的世界珍稀濒危物种、国家一级重点保护野生动物黑颈鹤,在每年重阳节来临之际,都会如约而至返回云南大山包黑颈鹤国家级自然保护区越冬。它们呼朋唤友、成群结队、热热闹闹地在这块高原净土上自由觅食、忘情嬉戏、纵情歌唱和舞蹈,     

大兴安岭猞猁冬季生境选择

采用机械布点法随机设置样线,对猞猁冬季生境选择进行了研究.包括海拔、植被类型、隐蔽度、坡度、坡位、坡向、距水源距离、距人为干扰距离等因素进行了调查,并利用栖息生境的偏爱指数进行计算分析.结果显示:猞猁冬季喜欢栖息在海拔800～1 000m,食物丰富度＞100 gDM/100 m2、隐蔽度≤0.3、水源距离＜1000m、人为干扰距离＞2 000 m的针阔混交林或针叶林中活动,喜欢活动于坡度较陡的生境,且多集中与上坡位.猞猁对坡向和雪深无明显的选择性.     

临安青山湖景区白鹭栖息地选择探析

以临安青山湖景区的白鹭为研究对象,采用样线法和样方法,对白鹭栖息地多个生态因子进行研究。结果表明,利用样方和对照样方中的水深度(t=-4.607,P=0.000)和距人工干扰距离(t=4.261,P=0.000)变量差异极显著;植被盖度(t=-2.474,P=0.017)变量差异显著;遮蔽度(t=-2.308,P=0.300)变量差异不显著。白鹭觅食地选择偏好为水深0～30 cm、距人工干扰距离50 m、植被盖度0～25%的区域。城市湿地中白鹭栖息生境选择的最大限制性因子为距人工干扰距离,因此,应尽量减少对白鹭的人为干扰,为其提供良好的栖息生境。     

呼伦贝尔草原黄羊春季采食生境的选择

本文采用数量化分析方法 ,对呼伦贝尔草原黄羊春季采食生境选择进行了研究。研究发现 ,影响呼伦贝尔草原黄羊春季采食生境选择的主要因子是放牧家畜干扰、水源、人为干扰 ,其次是坡度、坡位、坡向、植被类型、食物丰盛度 ,风向也有一定影响。其采食生境选择的倾向性依次为 :放牧家畜干扰距离 >2 0 0 0m ,水源距离≤ 10 0 0m ,坡度 5～ 2 5° ,人为干扰距离 >10 0 0m ,坡位在中坡 ,植被类型是针茅或针茅 羊草群落 ,食物丰盛度中等以上 ,阳坡或半阴半阳坡     

唐家河国家级自然保护区藏酋猴(Macaca thibetana)的生境选择

2013年3月至2014年2月,在唐家河国家级自然保护区毛香坝区域对对一群数量50只～60只的野生藏酋猴生境选择进行了研究.根据藏酋猴的活动位点,设置了96个20 m×20 m的植物样方,测定了植被类型、乔木密度、乔木胸径、乔木高度、郁闭度、灌丛盖度、地理性、海拔、坡向、坡度、坡位、水源距离、干扰距离等13个生态因子.对该群藏酋猴生境选择喜好程度分析表明,唐家河国家级自然保护区的藏酋猴偏好利用常绿落阔混交林、落叶阔叶林.猴群选择在乔木平均胸径20 cm ～30 cm和平均高度为11 rn～20 m的森林活动.它们不选择郁闭度＜20％的树林,主要位于海拔1 500m～2000m的地带活动.该群藏酋猴主要栖息于山坡面的森林,活动地点的坡度多介于20°～40°之间.该群藏酋猴对水源距离和干扰距离没有严格要求.     

瑞雪祥鹤

正贵州草海湿地与云南大山包一样,是云贵高原上黑颈鹤年复一年的越冬地。12月,一群黑颈鹤在这里觅食,一场小雪正轻轻地下着,雪花打在黑颈鹤黑白相间的羽毛上,宛如一幅中国水墨画。雪与鹤,都是祥瑞的象征。这一刻,气温应该在摄氏零度左右,但大自然呈现的,是一个宁静、祥和又温暖的瞬间。拍摄时间:2014年12月18日拍摄鸟名:黑颈鹤     

狗獾夏季生境选择

在黑龙江省方正林业局新风林场,通过痕迹检验法和洞穴辨别法对狗獾夏季生境选择进行研究的结果表明：狗獾夏季利用样方法和对照样方在乔木密度、乔木距离、灌木密度、植被盖度、距水源距离生态因子方面差异极显著（P〈0．001）,在乔木高度上差异显著（P〈0．05）,其余的生态因子无显著差异（P〉0．05）;相对于对照样方而言,狗獾夏季更偏爱在海拔322m左右、优势乔木为紫椴、乔木密度6．81左右、乔木高度在12m以上、乔木距离大于4．5m、乔木盖度小、灌木密度较高、植被盖度较低、距水源距离较近、坡位为中坡位的生境下活动;运用皮尔逊相关性检验模型的预测率达到97．2％,说明模型能够很好的反应狗獾夏季生境选择的基本情况。     

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.