【作者】 熊彪；

【导师】 艾训儒；

【作者基本信息】 湖北民族学院 ， 野生动植物保护与利用， 2010， 硕士

【摘要】 水杉(Metasequoia glyptostroboides Hu & Cheng)是中国著名的杉科孑遗植物。水杉原生种群只局限于鄂西(湖北利川)、渝东(重庆石柱)、湘西(湖南龙山)所形成的极狭窄三角形分布区内。目前对水杉的保护工作还做得很不够。本课题运用种群生态学、群落生态学、数量生态学的基本原理、基本方法,以水杉原生母树种群、群落及其生境为研究对象,在全面调查的基础上,对水杉原生种群的分布格局、年龄结构,水杉群落的类型、结构特征、数量特征、区系成分、物种多样性以及物种生态位等作定量研究。为分析水杉群落的演替规律,探讨外部影响对水杉原生种群及生境的扰动响应机制,提出其生物多样性保护与恢复的科学模式作参考。主要研究结论如下:(1)5746株水杉原生母树分布在湖北省利川市建南、谋道、汪营和忠路以及福宝山森林管护区的5个乡镇。(2)用偏离系数进行水杉原生母树种群聚集强度的测定,结果呈明显的集群分布。(3)现存水杉原生母树种群径级结构呈瓮型金字塔,为衰退种群。胸径在40～99cm的母树个体数多,为5 221株。胸径在60～99cm时,胸径生长速率最大;胸径在40cm以下时,树高生长速率最大;胸径在80～99cm时,是水杉旺盛生长期。胸径在120cm以上的母树,仍然生长良好。(4)水杉原生母树的生境类型大致可分为住宅旁、路旁、水旁、田旁、山坡等5种。东坡分布多,下坡分布多,0～20度的缓坡和斜坡多,集中分布在海拔高度1 100～1 300m的范围内。生长势最强的是南坡和东南坡。坡位和坡度都与水杉树高、胸径呈显著负相关。海拔高度与树高呈显著正相关,与胸径没有相关性。(5)影响水杉原生母树生长的干扰因子主要有砍伐、病虫害、耕作、雷击、大风、水蚀、社区影响和科研、考察等其它因子。这些因子的空间分布、发生频率、面积大小和规模强度等性质各不相同。近二十年来,已经有83株水杉原生母树因为各种原因死亡。(6)水杉原生母树群落植物属的地理分布共有173属,缺乏地中海区、西亚至中亚分布和中亚分布两种类型。群落乔木层植物共有64属77种,上层以枫香、柳杉、青冈栎、杉木、香椿、银杏、核桃、黑壳楠等优势种构成。灌木层有124属147种。(7)按照群落优势种丰富度指数和重要值可将群落划分为13类典型水杉原生母树群落。优势种分属14科18种,其中常绿4科5种。群落分层现象明显,乔木层树种偏少,灌木层发育完善。不同类型群落物种多样性指数不同。干扰较小的群落多样性高。海拔高度在1 000～1 200m时,物种多样性指数和均匀度指数最大。多样性指数在坡位上的数量分布呈现上坡>下坡>中坡的趋势。坡度在20度以上的群落物种多样性最大,在坡向上的变化趋势不明显。(8)在水杉原生母树群落中,生态位宽度较大的种群顺序是水杉、柳杉、杉木、香椿、枫香、锥栗、板栗。主要种群生态位相似性的所有组对中相似比例大于0.6的没有,只有14对相似性比例大于0.3;主要种群生态位重叠值集中在0～0.01之间,各种群对资源的共享趋势不明显。(9)自水杉被发现以来,原生生境不断被破坏,群落树种大大减少,林相逐渐单一。母树群落演替指数在4.12至7.86之间,已经完成针叶林先锋群落马尾松群落向针阔混交林的过渡,并将最终演替到顶极常绿阔叶林。如果环境保护好,干扰程度低,在沼泽湿地上、河谷旁完成从次生水杉林到水杉针阔混交林,然后到预顶极湿地水杉林这种发展演替过程是可能的。(10)水杉母树生境恶化、生长受到严重干扰的原因主要有人类活动、农业耕作、经费缺乏和自然灾害等。当前要做好资金筹措、资料普查等基础性工作。在此基础上,建立水杉母树数据库,封山育林,运用现代方法和技术努力恢复生境,改善水杉种群结构和群落结构。更多还原

【Abstract】 The relict plant Metasequoia glyptostroboides Hu & Cheng is a rare Chinese species with a limited distribution around the borders of Hubei Province, Hunan Province and Chongqing Municipality. While the protection for this relict plant is not enough. In this investigation, the basic characteristics of the original Metasequoia glyptostroboides mother trees population such as pattern, age structure, habitat, disturbance and death, and some characteristics of the communities involve succession, niche, species diversity and floristic element will be studied by quantitative analysis, using the methods of the Population Ecology, Community Ecology and Quantitative Ecology. The study will be benefit to analyze the succession of the original Metasequoia glyptostroboides mother trees communities, to discuss the mechanism of reaction of the population and its habitat for exoteric disturbance. And will be useful to protect and renew the biological diversity.The main conclusions:1. The original Metasequoia glyptostroboides mother trees with a number of 5 746 distribute in 5 towns in the Lichuan city of Hubei province, which are Jiannan, Moudao, Wangying, Zhonglu and the Fubao mountain forest resource managing and protecting liability section.2. The pattern of the original Metasequoia glyptostroboides mother trees population is contagious distribution.3. It indicates the original Metasequoia glyptostroboides mother trees population began to wither away that the age pyramid likes an urn. The rejuvenescence of the population is difficult because more of them belong to the middle age class. There are 5 221 individual numbers with the diameter at breast height (DBH) between 40 and 99 centimeters. The growth rate of DBH will be the maximum when DBH is 60 to 99 centimeters. While DBH is less 40 centimeters, the growth rate of height will be the maximum. The fast increase of the tree will appear when DBH is within 80 to 99 centimeters. The original Metasequoia glyptostroboides mother trees still grow well after DBH reaches 120 centimeters.4. The original Metasequoia glyptostroboides mother trees distribute abroad, such as the side of house, road or field and on mountain. Most of them distribute in slopes with a gradient of 0 to 20 and the altitude is 1 100 to 1 300. The eastern slope or a downward slope has more distribution. The mother trees have the best growth vigor while in southern slope or south-eastern slope. The correlation between slope position and slope gradient to DBH or height is marked negative. It is marked positive between altitude and height, while having no correlative relationship for altitude and DBH.5. The factors of disturbance for the original Metasequoia glyptostroboides mother trees are felling, constructing, blight, cultivation, lightning strike, gale, erosion and so on. The characters of them involve distribution, frequency, interval, intensity, incidence etc are each not same. In the past 20 years, there are 83 original Metasequoia glyptostroboides mother trees died for various reasons.6. The total generic areal types in the original Metasequoia glyptostroboides mother trees communities are 173, as the Mediterranean, West Asia to Central Asia and Central Asia are absent. Liquidambar formosana Hance,Cryptomeria fortunei Hooibrenk,Cyclobalanopsis tuldoides,Cunninghamia lanceolata,Toona Sinensis,Ginkgo biloba,Juglans regia and Lindera megaphylla etc make the tree layer. There are 77 species in tree layer and belong to 64 genera, while 147 species in shrub layer and belong to 124 genera.7. Thirteen typical communities are distinguished by the abundance and importance value of the dominant populations, which are 18 species and belong to 14 families, including evergreen plants 5 species, 4 families. Stratifications of the community are apparent. The shrub layer is more perfect than the tree layer. Various communities have various diversities. The community has the highest diversity while the height is 1 000 to 1 200, or the slope gradient is bigger than 20. The diversity has a tendency which is in the order of up slope > downward slope > middle slope for slope position, while has no trend for slope aspect.8. In the original Metasequoia glyptostroboides mother trees communities, the niche breadth is in the order of Metasequoia glyptostroboides > Cryptomeria fortunei Hooibrenk >Cunninghamia lanceolata Hook > Toona Sinensis > Liquidambar formosana Hance > Castanea henryi > Castanea mollissima Blume. No coefficient of niche similarity in all the species contrast is more than 0.6, while only 14 couples more than 0.3. The coefficient of niche overlap distributes between 0 and 0.01. It indicates that the tendency to share resources is not naked for the dominant populations.9. The suited habitat was havoced after the discovery of Metasequoia glyptostroboides. Species in the community decreased sharply and the forest form goes into simple by the lasting destruction. The range of indexes of succession is from 4.12 to 7.86. As the evergreen broad-leaf forest is the climax phase, the coniferous and broad leaf forest has already taken the place of pioneer community. If the environment is protected well, it is possible that the succession is from the secondary Metasequoia glyptostroboides forest to the coniferous and broad leaf forest, then to the preclimax Metasequoia glyptostroboides forest on the swamp wetlands or riverside.10. The main reasons of aggravating circumstances are human impacts, cultivation, lack of money and natural disasters. A database about Metasequoia glyptostroboides should be established on the base of financing and survey. It is a practical method to try to renew the habitat of Metasequoia glyptostroboides and ameliorate its structure by the modern ways and techniques.更多还原