应用环境筛与生殖力和种群增长模型研究钟萼木致濒因子

通过调查钟萼木天然分布种群的结实情况、种子更新能力、不同龄级小树分布以及影响小树不同时期生长的环境因子,采用分株编制种群静态生命表,应用环境筛分析种群在群落竞争中的生存情况;应用种子更新编制生殖力表,应用种子生殖与生殖生态分析种群增长力与影响种群增长的主要因素;应用因子变量的线性回归模型分析与筛选环境影响种群增长过程主要因子.结果 表明,该树种种子安全岛的缺失,种子深休眠抑制种子萌发,第1、2年生幼苗抗病虫害能力较弱,导致该树种生殖增长力差,使种群在自然竞争中处于弱势状态.种群动态增长模式研究表明,影响该树种种群增长因子作用强度表现为种群年龄＞郁闭度＞土壤湿度＞植被盖度＞种群密度＞坡度.在自然更新过程,幼树生长期长,30多年个体还不能进入生殖阶段,且具有生殖母树结果大小年明显,间隔期通常在3～4年,显著影响天然更新.

Study on the endangering factor of Bretschneidera sinensis with environmental sieve and fecundity and population increasing model

In order to investigate the fruiting situation of the natural distribution population of Bretschneidera sinensis, the distribution of young trees with different age grades and the environmental factors that affected the growth of young trees in different periods, the static life table of the population was prepared by using ramet, and the survival situation of the population in the community competition was analyzed by using environmental sieve. Seed regeneration was used to compile fertility table, and seed reproduction and reproductive ecology were used to analyze population growth force and main factors affecting population growth. The linear regression model of factor variables was used to analyze and screen the main factors affecting the population growth process. The results showed that the deficiency of seed safety island and the deep dormancy of seed for inhibiting sprout of seed, the first and second year seedlings had weak resistance to pests and diseases, which leaded to poor reproductive growth of the species and maked the population in a vulnerable state in natural competition. The model research of population dynamic increasing indicated that the effects of influencing population increasing put up the population age>crown density>soil humidity>vegetation density>population density>slop. The growth period of sapling was longer during the natural renewal and the individual over 30 years could not enter into the engender condition, the seed of engender mother-tree was of the abundant year and the deficient year, the interval period was between 3 to 4 years, which observably influenced the natural regeneration.