海南省东方市野生龙眼种群动态特征研究

野生龙眼是龙眼(Dimocarpus longan)的野生群体,是龙眼进行品种改良与创新的重要基因库。该研究对海南省东方市的野生龙眼资源进行实地调查,并从种群径级结构、静态生命表、存活曲线等方面进行了分析。结果表明:(1)东方市的野生龙眼所处群落的植被类型可以分为季雨林、热带雨林以及季雨林与热带雨林过渡带。(2)三种植被类型下野生龙眼种群大小依次为热带雨林过渡带季雨林。(3)三种植被类型下野生龙眼的存活曲线均趋于Deevey-Ⅱ型,种群各径级的死亡率基本接近。(4)数量变化动态指数表明季雨林、热带雨林区的野生龙眼种群为稳定型;过渡带的野生龙眼种群为增长型且趋于稳定。(5)时间序列预测分析表明,在未来的2、4个龄级后,季雨林下的野生龙眼种群从Ⅴ龄级之后的个体数呈现出增加的趋势,而热带雨林和过渡带是在Ⅳ级之后。从野生龙眼种群的整个发展阶段来看,目前三种植被类型下的野生龙眼幼年个体数相对丰富,种群维持有较充足的后备资源,中树、大树阶段的个体数能在现有基础上得到补充。继续保持现有野生龙眼种群分布的植株和生境斑块且采取有效保护措施,东方市的野生龙眼种群能有较好的恢复潜能。该研究的创新之处在于从不同植被类型下来分析东方市的种群动态结构,为处在不同植被类型的野生龙眼资源的种群特征提供了理论依据。

Structure and dynamic characteristics of wild longan population in Dongfang City, Hainan

Wild longan, the wild population of longan, is an important gene bank for the betterment and innovation of longan variety. In order to reveal the population distribution and the trend of population dynamics of wild longan, the population diameter structure, static life table, and survival curve of wild longan population were studied based on the field survey in Dongfang City, Hainan Province. The results were as followers:(1)Wild longan of communities of vegetation types which can be divided into monsoon forest, tropical rainforest and the transitional zone between monsoon forest and tropical rainforest.(2)The population size of wild longan was the largest in tropical rainforest, medium in the transitional zone and smallest in the monsoon forest.(3)The survival curve of the wild longan population showed that they approached a Deevey-II type, and the mortality rate in different size classes was similar.(4)A dynamic index of population size structure showed that their population are stabled in the monsoon forest and tropical rainforest, but its population of the transitional zone tended to be stabile.(5)Time-sequence models for wild longan population predicted that the number of different size classes will increase after two and four years. As a result, wild longan populations under monsoon forest tended to increase the number of individuals from the Age Class V later, while the rainforest and the transitional zone is after Age Class IV. From the entire stages of development of wild longan population, the number of the three vegetation types of wild longan were relatively abundant in young period, the population had a sufficient reserve resources, individual number of the medium tree and the big tree can be replenished in existing foundation. The wild longan population of Dongfang City can have a better recovery potential, as long as continue to maintain the current distribution of wild longan plants and habitat patches and take effective protective measures. The innovation of this paper is to analyze from different vegetation types of dynamic structure of wild longan population in Dongfang City, and this study provides information for population characteristics at different vegetation types of wild longan resources.