岷江上游高山林线附近优势树种土壤种子库和幼苗更新特征的研究

岷江上游地区高山/亚高山植被分布的坡向性分异显著，阴阳坡高山林线不仅物种组成差异明显，并且分布海拔呈现出阴坡高阳坡低的格局．阳坡林线树种主要是圆柏属乔木，林线类型多为渐变型，海拔高度大约在3 400m~3 800m；阴坡林线树种主要是冷杉，林线类型多为骤变型，海拔高度约在3 800m~4 400m．本研究采用土壤种子库物理筛选、室内萌发实验及野外群落调查等方法，对岷江上游地区阴坡岷江冷杉和阳坡祁连圆柏两类林线树种不同海拔梯度上土壤种子库以及幼苗库特征进行了调查，从土壤种子库和幼苗更新特征的角度对林线乔木树种种群更新特征进行了分析，进而对该地区高山林线在阴阳坡分布差异的原因进行了探讨，结果显示： 1．土壤种子库 阴坡：阴坡高山林线附近岷江冷杉土壤种子的平均密度大约为50.96粒/m2，其中树线以上10m处土壤种子密度为1.00粒/m2，树线处大约19.33粒/m2，林线交错带内土壤种子密度最高为136.83粒/m2，郁闭林内种子密度小于林线交错带，只有30.50粒/m2，种子平均空壳率为52％，霉变率达34%，完好种子只有6%．土壤种子库垂直分布特征为地被物层含种子比重最大，大约在67.50%左右；其次为0~2cm层，约18.84%左右；2~5cm层所占种子比例最小，约13.66%左右．霉变种子数量与土壤深度呈负相关． 阳坡：阳坡祁连圆柏土壤种子的平均密度为60.16粒/m2．树线以上10m处密度为1.92粒/m2，树线位置大约108.16粒/m2，林线交错带内平均为75.80粒/m2，郁闭林内种子密度小于林线交错带，只有20.00粒/m2．种子平均空壳率为36％，完好种子占49%，霉变率较低，大约为10%．阴阳坡林线树种土壤种子库垂直分布特征为：地被物层含种子最多，其次为0~4cm层，4~10cm层所占种子比例最小，霉变种子数量与土壤深度也呈负相关． 2． 幼苗库调查 阳坡：在树线以上区域没有发现幼苗，林线交错带内幼苗密度平均达3 250株/hm2，郁闭林内仅2 750株/ hm2．整个样地内1～2a幼苗很少甚至没有出现，3～10a的幼苗相对较多．空间分布上，祁连圆柏幼苗在林线交错带内接近随机分布，郁闭林内则介于随机分布和均匀分布之间． 阴坡：在树线以上幼苗密度为1 250株/ hm2，全部为1~2a幼苗，林线交错带内幼苗密度平均达7 000株/ hm2，郁闭林内达6 250株/ hm2．林线附近岷江冷杉幼苗丰富度以及幼苗的出现频率明显高于祁连圆柏，年龄结构也较祁连圆柏完整．岷江冷杉幼苗空间分布除了树线处幼苗的分布为随机分布，其他海拔则为集群分布． 3．从不同土壤深度的种子总量和幼苗数量的相关性检验发现，当年生幼苗数量跟表层种子总量相关性极显著, 但是两年生幼苗的数量与底层种子数量相关性显著．土壤种子在土壤中的垂直分布格局从一定程度上可以反映种子库的年际特征．岷江冷杉土壤种子库较丰富，种子散布后的存活力随着时间的变化逐渐下降，属于季节性瞬时种子库；祁连圆柏土壤种子散布格局为集群型分布，成熟种子大部分散布在母株冠幅内，属于永久性土壤种子库． 4．在阴坡林线交错带及以上区域还存在较为丰富的乔木土壤种子，并且在树线以上区域还发现了少量的岷江冷杉幼苗．从样地乔木的年龄结构发现，在林线交错带内上部到树线位置主要以幼龄林为主，且年龄结构完整，基本符合入侵性林线特征；阳坡林线交错带内幼苗出现频率很低，树线以上区域虽然存在种子库，但是没有幼苗出现，在林线交错带内乔木径级差距很大，年龄结构异常不完整，这种特征的林线将会面临两个可能结果：一种是维持现有状态，保持平衡；另外一种就是退化，但阳坡林线的实际动态趋势还有待长期定点研究． Treelines on the upper region of Minjiang River differ between the north aspect and the south aspect in their appearances, altitudes and tree species. On the north aspect, trees of Abies form a sharp and abrupt treeline ranging from 3800m to 4400m, while on the south the treeline is generally lower(3 400~3 800m), more open and gradual and mostly composed of Sabina. In this study, we examined the altitudinal gradients of soil seed banks and seedling recruitments at the treeline ecotones of a N-aspect and a S-aspect by using soil sieving, germination experiment and field investigations, analyzed the characteristics of population regeneration of tree species at the transitional zone and presented a analysis of the causes to the aspect-related difference in treeline patterns in the study area. Major results of our study include: 1． Soil seed bank N-aspect: Of the 50 plots investigated, the average density of soil seeds is 50.96/m2, in which well-formed seeds account for 6%, empty seeds 52%, parasitized seeds34%, and seeds damaged by animals 8%. The size of soil seed bank varies along altitude, being 1.00 seeds /m2 at the 10m above the treeline and ca.19.33 seeds/m2 at the upper limit of treeline. The highest density (136.83 seeds/m2) occurs at the treeline ecotone. By contrast, the density of soil seed for the closed forest is only 30.50 seeds/m2. In terms of vertical strata, 67.50% of the total seeds are at the surface layer, 18.84% at the middle layer (0~2cm) and 13.66% at deeper layer (2~5cm). The number of parasitized seeds is negatively correlated to soil depth. S-aspect: Of the 50 plots investigated, the average density of soil seeds is 60.16 seeds/m2, and the well-formed seeds account for 49%, empty seeds 36%, parasitized seeds10%, and seeds damaged by animals 1%. The size of soil seed bank varies along altitude, with 1.92 seeds/m2 recorded at the10m above the treeline，108.16 seeds/m2 at the upper limit of treeline, and 75.80 seeds/m2 at the treeline ecotone, while that for the closed forest is 20.00 seeds/m2. The number of seeds decreases with the depth of soil. As is on the N-aspect, the size of soil bank, from large to small, follows the order of the surface layer, the middle layer (0~4cm) and the bottom layer (4~10cm). The number of parasitized seeds is also negatively correlated to the depth of the soil. 2． Seedling bank N-aspect: A mean maximum seedling abundance of 31 000 seedlings/hm2 was recorded near alpine treeline at growing season. The density of seedlings is 1 250 seedlings/ha (all being 1 or 2 years old) at the alpine meadow 10m away above treeline, 7 000 seedlings/ha at treeline ecotone and 6 250 seedlings/ha for closed forest．The spatial distribution of Abies faxoniana seedlings is random at the upper limit of the treeline but clumped at other altitudes． S-aspect: No seedlings were found at the alpine meadow 10m away from the treeline. The density of seedlings was 3 250 seedlings/ha at treeline ecotone and 2 750 seedlings/ha for the closed forest．Hardly any 1 year current and 2 year-old seedlings appeared at the plots. The spatial distribution of Sabina przewalskii seedlings is random at treeline ecotone and between “random” and “even” forest closed forest． 3．Correlation tests of seedling population and seed bank at different soil layers indicated that the emergents were strongly correlated to seed bank at surface layer while the number of two-year seedlings was significantly correlated to the seed bank at the bottom of soil layer, indicating that germination mainly occurs at the soil surface while the middle or bottom layer was the reserve for non-germination or dead seeds. It can thus be postulated that Abies faxoniana soil seed bank is of seasonal transient type. By contrast, the soil seed bank of Sabina przewalskii is of persistent type and the soil seeds and seedlings of this species occurred more frequently near the islands of adult trees. 4．A good many soil seeds of both tree species were found near the treeline ecotone and above at N- and S-aspects. A few young seedlings were found above the Abies treeline. Investigation of five altitudinal transects respectively on N- and S-aspects indicated that Abies faxoniana has a more complete age structure than the stands of Sabina przewalskii. The age of firs decreased from closed forest to the upper limit of treeline, which suggests that the Abies treeline is advancing to higher altitude. While on the south aspect, only few Sabina przewalskii soil seeds and nearly no seedlings were found above the treeline ecotone. The stands exhibit extremely great difference in diameter classes with significantly incomplete age structure. This would lead to two possible results for the treelines: maintaining an equilibrium state at the current position or degenerating. But more studies should be carried out at longer time scales or larger spatial scales to understand whether the Sabina treeline is degenerating.

岷江干旱河谷三种蔷薇植物繁殖更新研究

繁殖更新是植物生活史的重要阶段，在退化生态系统中，植物繁殖更新能力往往较差，是植被恢复的限制环节，因而也成为恢复研究重点和核心。本研究选择岷江干旱河谷广泛分布的三种蔷薇：多苞蔷薇（R. multibracteata）、黄蔷薇（R. hugonis）和川滇蔷薇（R. soulieana）为研究对象，通过野外调查，在查明其生长、繁殖更新状况的基础上，采用控制和模拟实验，对种子和幼苗阶段进行了深入研究，综合分析更新潜力，并提出相对应的促进更新和植被恢复措施。主要结论如下： 1）三种蔷薇在岷江干旱河谷广泛分布，生长和繁殖状况良好，结实量大。各生长指标：株高、基径和冠幅，繁殖指标：结实数量、重量和单果重量都具有显著的空间差异性。基径对多苞蔷薇结实量影响最大；而冠幅对黄蔷薇结实量影响最大。海拔和纬度是对蔷薇生长和繁殖影响最大的环境因素，随着海拔和纬度的升高，植株生长更高大，结实量增加；坡度和坡向对其生长和繁殖也有一定影响，随着坡度 和坡向增加，蔷薇生长和结实受到抑制。 2）三种蔷薇在岷江干旱河谷更新现状不佳, 但更新潜力大。活力种子比率低，动物取食以及两年生幼苗的大量死亡是蔷薇更新的主要限制因素。多苞蔷薇和黄蔷薇的结实率低，川滇蔷薇较高。三种蔷薇种子产量大，但种子质量较差，更新具有充足的种源。三种蔷薇都能形成持久种子库，种子库中种子总量大，但有效种子少，黄蔷薇被动物啃食的比例很高，多苞蔷薇和川滇蔷薇也有一部分种子受到动物破坏。三种蔷薇幼苗库组成特征表现为，当年生幼苗所占比例很高，年龄较大幼苗所占比例小。 3）三种蔷薇都具有不同程度休眠，未经处理种子的发芽率极低。黄蔷薇休眠程度最深，为深度生理休眠；多苞蔷薇为中度生理休眠；川滇蔷薇为非深度生理休眠。三种蔷薇种子在形态上发育成熟，种皮具有透水性。蔷薇果果肉和瘦果中含有抑制物质，其浸泡液抑制了油菜种子萌发，果肉抑制作用更强，果肉和瘦果浸泡液的抑制程度分别为：川滇蔷薇>黄蔷薇>多苞蔷薇。切割和硫酸腐蚀提高了川滇蔷薇种子的发芽能力，而对多苞蔷薇和黄蔷薇没有影响。完全去除瘦果果皮和种皮提高了多苞蔷薇种子发芽率，但对黄蔷薇没有影响。赤霉素和烟水对蔷薇种子萌发没有促进作用。三种蔷薇打破休眠所需低温层积时间分别为：黄蔷薇>多苞蔷薇>川滇蔷薇。对于多苞蔷薇和川滇蔷薇，层积前对种子进行硫酸腐蚀或暖温层积能缩短低温层积时间，提高发芽率。对于多苞蔷薇，变温层积中暖温层积和低温层积具有一定的负补性，即延长暖温层积可以缩短种子萌发对低温层积的需要。 4）多苞蔷薇种子形态特征和种子休眠与萌发在不同海拔梯度间存在较大差异。种子采集时间、采集季节和干藏影响多苞蔷薇和川滇蔷薇的种子休眠。多苞蔷薇果实大小、种子大小和千粒重、种皮厚度随海拔升高而增加，而种子饱满率和活力随海拔升高而降低，种子休眠程度也随海拔升高而增加。种皮厚度与种子大小、千粒重成正相关关系，硫酸腐蚀后的种子经过不同时间的低温层积后，种子发芽率与种皮厚度、种子大小、千粒重、海拔成正相关关系。2006 年采集川滇蔷薇和多苞蔷薇种子休眠程度较2005 年低。种子休眠随种子年龄增加而减弱。高温和干旱能减轻多苞蔷薇和川滇蔷薇种子休眠。 5）三种蔷薇的生长和生物量积累在干旱胁迫条件下受到抑制，而生物量分配、叶片形态特征和水分利用特征等都发生了变化。三种蔷薇的根、茎、叶各器官生物量以及总生物量等在干旱胁迫下明显减小，叶片脱落数量增加。在干旱胁迫条件下，较多的生物量分配到地下部分，从而这使R/S 明显增加。比叶面积（SLA）和冠层面积比（LAR）对干旱胁迫的反应不敏感，仅有部分物种在干旱胁迫条件下发生了变化，并且其变化特点在不同年龄幼苗之间有一定差异。干旱胁迫对WUE 的影响在不同物种间存在差异。多苞蔷薇和黄蔷薇的WUE 随着干旱胁迫的增加而增大， 而川滇蔷薇的WUE 则随干旱胁迫增加而减小。在干旱胁迫条件下，多苞蔷薇和黄蔷薇叶片脱落量和生物量减小幅度较川滇蔷薇大，表明其抗旱能力较强。在干旱胁迫条件，三种蔷薇两年生幼苗的生物量减小幅度较当年生幼苗小，表明两年生幼苗的抗旱能力更强。 6）两种植被恢复措施中，幼苗移栽比播种具有更好的植被恢复效果。播种后，蔷薇种子的发芽率较高，但出苗率都很低，即使出苗，幼苗也几乎在一月内全部死亡。 三种微生境条件下（灌木、半灌木和裸地），种子出苗和幼苗成活没有差异。移栽幼苗总体死亡率都比较低，小于20％。特别是两年生幼苗死亡率更低，小于2％。移栽后的幼苗生长状况良好，在整个生长季中，各生长指标不断增加。生境对幼苗的存活率没有显著影响，但对于幼苗的生长和生物量积累有一定影响，裸地更有利于幼苗生长和生物量积累。与当年生幼苗相比，两年生幼苗具有更高的成活率。总之，三种蔷薇在干旱河谷分布广泛、生长繁殖状况良好，结实量大，具有丰富种源，繁殖更新潜力大，但繁殖更新状况不佳；种子散布后动物对种子的取食、种子的深度休眠过程、种子出苗以及当年生幼苗的存活和定居是更新的主要限制环节。水分是影响结实、种子休眠解除和萌发，幼苗存活和定居的最主要的限制因素。在植被恢复中，应在种子成熟季节大量采集种子，在室内打破休眠后进行人工播种，培育两年生幼苗，通过幼苗移栽方式进行植被恢复。川滇蔷薇应栽种在相对湿润的过渡区，而多苞蔷薇和黄蔷薇可以应用于核心区植被恢复。 Regeneration is an important phase in plant life cycle. It has been a key component of ecological restoration in degradation ecosystem in which plants commonly has poor regeneration. In this paper, we investigated the natural growth, propagation and regeneration status of native three rose species, Rosa multibracteata, R. hugonis and R. soulieana, and analysis the limitation in seed germination and seedling establishment stages. Advice on facilitating the use of these plants in restoration based on the results has been proposed. The results were as follows: 1) Three rose plants widely distributed in the dry valley of the Minjiang River, and made a good performance in growth and propagation. There were significant spatial differences in each growth parameter, such as ramet height, basal diameter, crown diameter and propagation parameters including hip number of a clump, hip mass of a clump and a hip mass. Basa diameter was the most important growth parameter influencing fruit number for R. multibracteata and crown diameter was for R. hugoni. Altitude and latitude had the greatest effect on the growth and propagation of rose plants among environmental conditions. Each parameter of growth and propagation increased with the increase of altitude and latitude. In addition, the increase of slope and aspect limited the growth and propagation. 2) Three rose plants had poor natural regeneration, but great regeneration potential. Low seed viability, predation and higher mortality of current year old seedlings were the limitation in regeneration. R. multibracteata and R. hugonis had higher fruiting rates than R. souliean. All three plants produced a great number of seeds, while their viability was poor. Three rose plants had persistent seed banks, with high total seed number but very low viable seed density. Predation was most severe in R. hugonis, and it also existed to some degree in R. multibracteata and R. soulieana. The seedling age-structure was characteristic of current-year seedlings predominating and few older seedlings were observed. 3) Three rose seeds were dormant and untreated seeds germinated with very low germination percentages. The rose seeds had morphological mature embryos, and achenes were permeable. Some inhabit substances existed in hips and achenes for the extracts of hips and achenes inhibited germination of Brassica campestris. The inhibition effect of the extracts of three rose hip and achenes was R. soulieana>R. hugonis>R. multibracteata. Mechanical and H2SO4 scarification increased R. soulieana germination but had no effect on germination of R. hugonis and R. multibracteata seeds. Full removal of pericarp and testa improved the germination of R. multibracteata but did not affect R. hugonis germination. GA3 and smoke water had no positive effect on rose seed germination. The periods of cold stratification required to released seed dormancy was R. hugonis > R. soulieana >R. multibracteata. H2SO4 scarification and warm stratification shortened cold stratification to release dormancy for R. soulieana and R. multibracteata. Warm stratification had complementary effect for cold stratification, i.e. the longer warm stratification seeds received, the shorter cold stratification were required to obtain the same germination percentage. Three rose seeds had different kinds of dormancy; R. hugonis has deep physiological dormancy, R. multibracteata with intermediate physiological dormancy and R. souliean non-deep physiological dormancy. 4）The seeds traits and dormancy of R. multibracteata showed significant difference across altitudes. Year and season of seed collection had significant effect on seed dormancy for both R. souliean and R. multibracteata. Hip size, seed size, seed weight, seed coat thickness and seed dormancy level increased with the increase of the altitude. There were positive relations between seed coat thickness with seed size and seed weight. Germination percentage of seeds treated with H2SO4 scarification following different periods of cold stratification showed positive relation with seed coat thickness, seed size, seed weight and altitude. Seeds of R. souliean and R. multibracteata collected in 2006 had low dormancy level than those collected in 2005. Seed dormancy decreased with increasing seeds age. High temperature and drought were associated with low dormancy level. 5) Seedling growth, the total dry mass and their components of seedlings were reduced, while leaf senescence accelerated under drought stress. More biomass allocation to root system resulted in higher R/S ratio under drought. Water-use efficiency (WUE) of R. multibracteata and R. hugonis increased, while it declined for R. soulieana under drought stress. R. soulieana seedlings had poor drought-resistance capacity it had more senescent leaves, and its reduction of biomass was stronger than two other rose plants under drought. The reduction degree of one year old seedlings under drought stress was slighter than that of current year seedlings. Therefore, one year old seedling was more drought-resistent compared to current year seedlings. 6）Planting seedlings may have better effect in comparison with direct seeding. Most seeds germinated after seeding, but seedling emergence was very low. More than 80 % seedlings from direct seeding died within a months after emergence. Seedling emergence and survival rate did not show difference among microhabitats. Mortality rates of seedlings artificially planted in microhabitats were general lower than 20 %, and the mortality rate of one year old seedlings was lower than 2 %. Each grow parameter including plant height, leaf number and branch number continually increased after planting. Microhabitat type had effect on the growth parameter and biomass production, but it did not influence the seedling survival. Bare land tended to facilitate seedling growth. One year old seedlings had higher survival rate than current year seedlings. In conculsion, the three rose had wide distribution in the dry valley of the Minjiang River. They produced many seeds and had tolerance to drought stress to some degree. But they had poor regeneration in habitats may be caused by predation, seed dormancy，and high mortality in current year seedlings. We recommend that rose plants should be utilized in restoration by planting two-year old seedlings in spring. A large quantity of seeds should be collected artificially in autumn, release seed dormancy in room, and then cultivate two-year old seedlings by seeding in particular container. R. soulieana seedling probably be planted in transition area, and R. multibracteata and R. hugonis can be used in core area of the dry valley of the Minjiang River.

镇海棘螈和大凉疣螈年龄结构研究

通过趾骨切片可以准确鉴定年龄，了解一个物种的最长寿命，也为我们研究确定一个物种的生长特点、性成熟期,以及一个地区一个物种的年龄结构、种群生态(Marnell，1998)和群落生态提供重要信息(Morrison，et a1.，2004)。 本论文使用骨骼鉴龄法对中国浙江省宁波市北仑瑞岩寺林场的镇海棘螈（Echinotriton chinhaiensis）雌性繁群进行了年龄结构研究。结果显示：第一次参加繁殖的年龄为3龄；繁群中数量占优势的是5龄、6龄。而在6龄以后参加繁殖的雌性个体数便开始随着年龄的增大而逐渐减少。参加繁殖的雌性年龄最大个体为8龄。平均年龄为5.13龄。同时对其年龄和头体长、体全长的相关性检验,发现其年龄与头体长和体全长不相关,镇海棘螈雌性的生长方式表现为性成熟后能量主要用于繁殖。 另外,对李子坪大凉疣螈(Tylototriton taliangensis) 雄性繁群进行了年龄结构研究。结果显示：大凉疣螈雄性第一次参加繁殖的年龄为4龄；繁群中数量占优势的是5龄、6龄、7龄。而在7龄以后参加繁殖的雄性个体数便开始随着年龄的增大而逐渐减少。参加繁殖的雄性中年龄最大的个体为10龄。平均年龄为6.7龄。对其年龄和头体长、体全长的相关性检验,发现其年龄与头体长和体全长不相关,大凉疣螈雄性生长特点也表现为性成熟后生长缓慢的特点。 研究材料方面，本文采用野外采样与标本馆标本相结合的方式获得了中国蝾螈科2个重要保护物种繁殖群体的剪（指）趾材料，使得建立于其上的年龄结构工作更加可靠、更加具有代表性。 此外,本论文讨论了镇海棘螈瑞岩寺种群繁殖总量年度间的差异及其产生原因。将1998、1999、2000、2008、2009年镇海棘螈（Echinotriton chinhaiensis） 瑞岩寺种群的繁殖量进行比较，发现虽然雌性平均窝卵数比较稳定，但繁殖总量小于1998、1999、2000年任何一年总产卵量的50%。对2008年镇海棘螈繁殖量大幅下降的原因分析发现, 2007年9、10月影响严重台风的两次强台风、瑞岩寺景区开发等因素可能是造成近年该种群繁殖量大幅下降的原因。而2008年初50年不遇的低温是否影响镇海棘螈的繁殖值得进一步追踪研究。2009年繁殖量较2008年没有明显的增长，可能是由于2007年的台风影响了其繁殖营养的积累。台风的影响可能存在滞后现象,对此有待进一步监测证明。 本研究首次对中国蝾螈科物种进行的年龄结构鉴定，为进一步了解中国蝾螈科动物的种群生态打下了坚实的基础。 Using skeletochronology, we can know the life span of a species, age of reaching sexual mature, and of course age structure, which are vital(Morrison，et a1.，2004). Skeletochronology was performed on Echinotriton chinhaiensis Ruiyansi female population. The result shows that: The oldest individuals were 8 years old and the youngest ones were 3 years old. Individuals of age class 5(39.13%) and 6(21.74%) were most numerous. The number of individuals participated in reproduction decreased with the increase of age after the sixth year. Average age is 5.13 years. There is no correlation between age and body size (SVL and TL). For female chinhai salamander, energy is devoted to reproduction after reaching sexual maturation. While using skeletochronology to study Tylototriton taliangensis Liziping male population, the oldest individuals is 10 years old, and the youngest ones is 4 years old. Individuals of the age class 5, 6, and 7 dominat this population. The number of individuals decrease with the increase of age also after the seventh year. Average age is 6.7 years old in this population. there is also no correlation between age and body size (SVL and TL).It turned out that T. taliangensis tend to grow slowly after reaching sexual maturation. In this thesis, specimens from both wild and museum were used to gain enough toe clipping samples. A big sample size guarantees the reliability of this study. In the meantime, E. chinhaiensis’s annual reproduction of the year 1998, 1999, 2000 ,2008,and 2009 was compared. The result shows there is a huge decline in E. chinhaiensis’s annual reproduction in 2008,even the egg clutch is very stable. After analyzing, it turned out the huge decline in 2008 was probably caused by typhoon in 2007, besides the effect of tourism development and cash crop planting. While the impact of extreme weather of 2008 on reproduction needs further investigation. In the year 2009, there is no obvious increase in annual reproduction. It maybe due to lasting impact of typhoon in 2007. It is the first age-structure study on these two Chinese salamanders. A solid foundation was laid for further population ecology study of these two species.

不同森林管理预案下友好林业局森林景观的动态变化

Knowledge about cumulative effects of forest management alternatives on forest landscape is required to make forest management decision. In this paper,a spatially explicit landscape model,LANDIS,was applied to simulate forest landscape changes in 200 years under four management alternatives (no cutting,clearcutting,selective cutting I and II) in Youhao Forestry Bureau located in Small Khingan Mountains. APACK was used to calculate distribution area of the representative species and species age cohort for six species. The results showed:1) timber harvest decreased area percentage of representative conifer species,Pinus koraiensis,Picea koraiensis and Picea jezoensis,Larix gmelinii to some extent compared to no cutting. The most influencing cutting mode for the area percentage of Tilia amurensis and Quercus mongolica was selective cutting II,followed by selective cutting I and clearcutting. To the contrast,the change of area percentage of Betula phatyphylla was contrary to the management alternatives; 2) As to species age cohort composition,timber harvest significantly changed age structure,that is,it decreased over-matured age cohort of representative species,and increased seedling and middle-age cohort (B. phatyphylla was not included,because its area percentage of over-mature age cohort was the highest under clearcutting than other three scenarios).

Wybiórczość siedliskowa dzięcioła średniego Dendrocopos medius w zróżnicowanych ekosystemach leśnych

Wydział Biologii

A perceção de qualidade de vida do idoso institucionalizado

A institucionalização do idoso é cada vez mais uma realidade constante, o que faz com que a população idosa tenha um peso maior na estrutura etária, quer por necessidades próprias quer por necessidades sentidas pelos seus cuidadores. A fim de darmos resposta aos objetivos delineados; saber qual a perceção dos idosos sobre a Qualidade de vida; conhecer o quão satisfeitos estão os idosos com a sua saúde e conhecer a qualidade de vida dos idosos no domínio físico, psicológico, nas relações sociais e no meio ambiente. Como instrumento de recolha de dados, utilizamos a escala Whoqol-Bref e recolhemos os dados através de uma entrevista a 28 idosos com uma média de idades de 85,5 anos, institucionalizados na Residence Grande Fontaine, na Suíça. Após a colheita de dados, estes foram analisados através do programa informático Microsoft Office Excel 2010 e organizados em gráficos e tabelas. Tendo em conta os parâmetros utilizados pela escala supra referida para avaliação da qualidade de vida, conclui-se que os idosos inquiridos apresentam uma qualidade de vida no nível "Boa". Relativamente à satisfação com a sua saúde os idosos inquiridos apresentavam-se no nível "nem satisfeitos nem insatisfeitos com a mesma". Em relação a avaliação da qualidade de vida no que se refere aos quatro domínios da escala, o domínio com melhor percentagem é do meio ambiente e o domínio com menor classificação refere-se ao domínio das relações sociais.

Ecological And Metabolic Studies On Free-Living Nematodes From An Estuarine Mud-Flat

Nematodes from a mud-flat in the river Lynher estuary, Cornwall, U.K., have a population density ranging between 8 and 9 × 106 m−2 in the winter months, corresponding to a dry weight of 1·4 and 1·6 g m−2. They reach a peak abundance of 22·86 × 106 m−2 (3·4 g) in May. About 40 species are present, and the species composition remained seasonally stable over the period of study. Analysis of age-structure suggests that the major species have continuous asynchronous reproduction. Respiration rates of 16 species have been determined at 20 °C using Cartesian diver respirometry. For five species, respiration/body size regressions were obtained in the form log10R = log10a+b log10V, where R = respiration in nl O2 ind−1 h−1 and V = body volume in nl: Mesotheristus setosus (log10a = −0·04,b = 0·74), Sphaerolaimus hirsutus (log10a = 0·11, b = 0·68), Axonolaimus paraspinosus (log10a = 0·00, b = 0·79), Metachromadora vivipara (log10a = −0·59, b = 1·07), Praeacanthonchus punctatus (log10a = 0·00, b = 0·55). For the remaining 11 species, several animals were used in each diver and, by assuming b = 0·75, log10a′ values were calculated: Viscosia viscosa (log10a′ = 0·188), Innocuonema tentabundum (−0·012), Ptycholaimellus ponticus (−0·081), Odontophora setosa (−0·092), Sphaerolaimus balticus (−0·112), Dichromadora cephalata (−0·133), Atrochromadora microlaima (−0·142), Cylindrotheristus normandicus (−0·150), Terschellingialongicaudata (−0·170), Sabatieria pulchra (−0·197), Terschellingia communis (−0·277). These values are compared with recalculated values for other species from the literature. Annual respiration of the nematode community is 28·01 O2 m−2, equivalent to 11·2 g carbon metabolised. Community respiration is compared with figures from N. American saltmarshes. At 20 °C, a respiration of about 61 O2 m−2 year−1 g−1 wet weight of nematodes appears to be typical. Annual production is estimated to be 6·6 g C m−2. The correlation between feeding-group, body-size, habitat and the repiration rate of individual species is discussed.

Pinus and Prostomis: a dendrochronological and palaeoentomological study of a study of a mid-Holocene woodland in Eastern England

Tree-ring analysis of sub-fossil Pinus sylvestris L. and Quercus sp. and their associated sub-fossil insect assemblages from tree rot holes have been used to study a prehistoric forest buried in the basal peats at Tyrham Hall Quarry, Hatfield Moors SSSI, in the Humberhead Levels, eastern England. The site provided a rare opportunity to examine the date, composition, age structure and entomological biodiversity of a mid-Holocene Pinus-dominated forest. The combined approaches of dendrochronology and palaeoentomology have enabled a detailed picture of the forest to be reconstructed, within a precise time frame. The Pinus chronology has been precisely dated to 2921- 2445 BC against the English Quercus master curve and represents the first English Pinus chronology to be dendrochronologically dated. A suite of important xylophilous (wood-loving) beetles that are today very rare and four species that no longer live within the British Isles were also recovered, their disappearance associated with the decline in woodland habitats as well as possible climate change. The sub-fossil insects indicate that the characteristic species of the site's modern-day fauna were already in place 4000 years ago. These findings have important implications in terms of maintaining long-term invertebrate biodiversity of mire sites.

An assessment of the earth pressure coefficient in overconsolidated clays

The determination of the earth pressure coefficient K 0 in a natural clay deposit is a problem of considerable significance in geotechnical engineering. While the methods for evaluation of K 0 are reliable for normally consolidated soils, significant difficulties still exist in evaluating K 0 in overconsolidated clays, given that it is influenced by the stress history of the material, together with the age, structure, mineralogical composition and depositional environment. Indeed, some of these factors are responsible for the soil becoming anisotropic. The existing framework for prediction of K 0 in overconsolidated soils does not account for any influences caused by anisotropy. The work reported in this paper evaluates the validity of a revised relationship between K 0oc and OCR (overconsolidation ratio) using data obtained from laboratory investigations. The tests were performed on reconstituted and undisturbed samples of Belfast Upper Boulder Clay, London Clay and Gault Clay. Tests were also performed on reconstituted samples of kaolin. The values of K 0oc were determined using various approaches, including on-sample measurements. The results have confirmed that reliable predictions of K 0oc can be made using the proposed relationship.

Hunting in a Tropical Rainforest:Evidence from the Terminal Pleistocene at Lobang Hangus, Niah Caves, Sarawak

The Terminal Pleistocene zooarchaeological evidence from Lobang Hangus, an east-facing entrance to the Niah Cave complex, provides unique insights into the hunting habits of the human inhabitants of this cave. The composition and structure of the vertebrate accumulation indicates that a variety of locally available terrestrial, arboreal and aquatic taxa were being exploited, The age structure of the principal predated species, the presence of bone points and evidence from modern rainforest hunting combine to suggest that some form of projectile weaponry as well as trapping technologies were probably being employed by the hunters at Niah before the end of the Pleistocene. Copyright (C) 2009 John Wiley & Sons, Ltd.

Climatic signals in the life histories of insects:the distribution and abundance of heather psyllids (Strophingia spp.) in the UK

1. The population density and age structure of two species of heather psyllid Strophingia ericae and Strophingia cinereae, feeding on Calluna vulgaris and Erica cinerea, respectively, were sampled using standardized methods at locations throughout Britain. Locations were chosen to represent the full latitudinal and altitudinal range of the host plants.

2. The paper explains how spatial variation in thermal environment, insect life-history characteristics and physiology, and plant distribution, interact to provide the mechanisms that determine the range and abundance of Strophingia spp.

3. Strophingia ericae and S. cinereae, despite the similarity in the spatial distribution patterns of their host plants within Britain, display strongly contrasting geographical ranges and corresponding life-history strategies. Strophingia ericae is found on its host plant throughout Britain but S. cinereae is restricted to low elevation sites south of the Mersey-Humber line and occupies only part of the latitudinal and altitudinal range of its host plant. There is no evidence to suggest that S. ericae has reached its potential altitudinal or latitudinal limit in the UK, even though its host plant appears to reach its altitudinal limit.

4. There was little difference in the ability of the two Strophingia spp. to survive shortterm exposure to temperatures as low as - 15 degrees C and low winter temperatures probably do not limit distribution in S. cinereae.

5. Population density of S. ericae was not related to altitude but showed a weak correlation with latitude. The spread of larval instars present at a site, measured as an index of instar homogeneity, was significantly correlated with a range of temperature related variables, of which May mean temperature and length of growing season above 3 degrees C (calculated using the Lennon and Turner climatic model) were the most significant. Factor analysis did not improve the level of correlation significantly above those obtained for single climatic variables. The data confirmed that S. ericae has a I year life cycle at the lowest elevations and a 2 year life cycle at the higher elevations. However, there was no evidence, as previously suggested, for an abrupt change from a one to a 2 year life cycle in S. ericae with increasing altitudes or latitudes.

6. By contrast with S. ericae, S. cinereae had an obligatory 1 year life cycle, its population decreased with altitude and the index of instar homogeneity showed little correlation with single temperature variables. Moreover, it occupied only part of the range of its host plant and its spatial distribution in the UK could be predicted with 96% accuracy using selected variables in discriminant analysis.

7. The life histories of the congeneric heather psyllids reflect adaptations that allow them to exploit host plants with different distributions in climatic and thereby geographical space. Strophingia ericae has the flexible life history that enables it to exploit C. vulgaris throughout its European boreal temperate range. Strophingia cinereae has a less flexible life history and is adapted for living on an oceanic temperate host. While the geographic ranges of the two Strophingia spp. overlap within the UK, the psyllids appear to respond differently to variation in their thermal environment.

Aging policy: a case study of co-ordination in Canadian governments

ABSTRACT Canada is an aging society. The number of people aged sixty-five and over is rising, while the number of people under twenty is declining. These two concurrent changes in the age structure have produced a sh~ft in the demographic composition of Canada which is commonly referred to as the aging phenomenon. Regardless of whether or not the number of people under twenty continues to decline, the number of elderly in Canada will almost double over the next twenty years. This rapidly growing elderly clientele will doubtless have an impact on Canadian governments. Federal, provincial and municipal governments are presently providing a variety of programs that have a special bearing on the aged and most senior citizens are beneficiaries of one or more of these programs. The ramifications of a rapidly growing elderly clientele are obvious. In order to cope with the impact of a significant increase in the number of elderly persons, the development and implementation of aging policy must be co-ordinated at each level of government and between and among levels of government. If aging policy is not co-ordinated, the results are likely to be: inappropriate policy decisions; duplication and overlap; and, ineffective and irresponsive services. No one benefits from these results. The need for co-ordination is apparent. The purpose of this thesis is to examine existing governmental efforts to co-ordinate policy in the field of aging. These efforts are examined by focusing on interactions directed at co-ordination between and among major actors in aging policy. A framework is used to structure the description and analysis of these interactions. The variables of formalisation and intensity and the concept of power are instrumental in analysing interactions for co-ordination. The underlying intent of this thesis is to discover some of the main gaps in existing governmental efforts to co~ordinate aging policy. Gaps are, in fact, discovered. Several explanations for the existence of gaps in interactions for co-ordination are discussed. A major hypothesis involving a relationship between a bureaucratic form of organisation and interactions for coordination is suggested. Finally, three recommendations for improving co-ordination in aging policy are offered.

La "migration de remplacement" au Québec : à quel point peut-on compter sur l’immigration pour contrer les problèmes démographiques appréhendés?

Un document accompagne le mémoire et est disponible pour consultation au Centre de conservation des bibliothèques de l'Université de Montréal (http://www.bib.umontreal.ca/conservation/).

Implications of Government Sponsored Social Security and Welfare Schemes on Socioeconomic Status of Small Scale Marine Fisherfolk in Kerala

A socio-economic research is required as an attempt to address the socio-economic issues facing small-scale fisheries. A study of the socio economic conditions of small-scale fishermen is a prerequisite for good design and successful implementation of effective assistance Programmes. It will provide an overall pidure of the structure, activities and standards of living of small-scale fisherfolk The study is confined to the coastal districts of Ernakulam, Thrissur and Malappuram districts. It also gives a picture of socio-economic conditions of the fisher folk in the study area. The variables that may depict the standard of living of the small-scale fisherfolk are occupational structure, family size, age structure, income, expenditure, education, housing and other social amenities. It attempts to see the asset creation of the fisherfolk with the help of government agencies, and the nature of savings and expenditure pattern of the fisherfolk. It also provides a picture of the indebtedness of the fisherfolk in the study area. The study analyses the schemes implemented by the government through its agencies, like Fisheries Department, Matsyaboard, and Matsyafed; and the awareness of fisherfolk regarding these schemes, their attitude and reactions, the extent of accessibility, and the viability of the schemes.