贵州习水杜鹃群落结构和种群动态分析

Studies on Community Structure and Population Dynamics of Rhododendron xishuiense in Guizhou

摘要:

为了探究贵州习水国家级自然保护区特有植物习水杜鹃(Rhododendron xishuiense)种群现状，揭示该种群动态及濒危原因，加强对该种群的保护，在该保护区设置了13条样线，调查习水杜鹃在保护区的分布情况。对现存习水杜鹃分布地开展样地调查，采用4个多样性指数和Raunkiear生活型系统分析习水杜鹃分布群落的结构，通过空间代替时间得到种群年龄结构，据此编制静态生命表，并绘制存活曲线及4个生存函数曲线分析习水杜鹃种群的动态特征。结果表明，共有维管植物27科42属65种，其中种子植物24科39属62种，蕨类植物3科3属3种。以高位芽的物种数最多，有56种，占物种总数的86.15%，其次是地上芽植物、地面芽植物、地下芽植物。群落的多样性指数均表现为乔木层 > 灌木层 > 草本层，乔木层占有绝对的优势地位。种群年龄结构呈“金字塔”型，种群幼苗个体相对于整个种群数量较多；种群存活曲线属于Deevey Ⅱ型，个体数量随着年龄的增加而不断减少；种群生存率持续下降，尤以中后期减少速度较快，种群衰退。习水杜鹃种群分布范围狭窄，分布群落物种多样性高，幼苗相对较多表现为增长型，但种群总量极少，且遭受较强的竞争，建议采取适当措施促进幼苗幼树生长，使中年个体得到有效补充，以保障种群持续增长。

Abstract:

In order to explore the population status of Rhododendron xishuiense, an endemic plant in Xishui National Nature Reserve, Guizhou, reveal the dynamics and endangered causes of its population and strengthen its protection, the distribution of R. xishuiense was investigated along 13 transects in the reserve. The population structure of R. xishuiense distribution community was analyzed by using four diversity indexes and Raunkiear life form, the population age structure was obtained by replacing time with space. Thus, the static life table was compiled, and the survival curve and four survival function curves were drawn to analyze the dynamic characteristics of R. xishuiense population. The results showed that there were 65 species of vascular plants in 27 families, 42 genera, in which 62 species of seed plants in 24 families, 39 genera and 3 species of ferns in 3 families and 3 genera. The number of phanerophyte was the largest with 56 species in total, accounting for 86.15% to all species, followed by chamaephyte, hemicryptophyte, and geophyte. All of diversity indexes of the community was in the order of tree layer > shrub layer > herb layer, indicating that tree layer had an absolute dominant position. The age structure of the population was pyramidal, and the number of seedlings in population was large in whole population; the population survival curve was Deevey II type, and the number of individuals decreased along age, the population survival rate continued to decline, especially in the middle and late period of rapid decline, population decline. Therefore, with its narrow distribution range and high diversity, the number of seedlings showed an increasing pattern, but due to the suffering of intense competition, the R. xishuiense had a very small population of species. It was suggested to take appropriate measures to promote the growth of seedlings and young trees, so that middle-aged individuals can be effectively supplemented, so as to ensure the sustainable growth of the population.