海三棱藨草种群的密度与生物量动态

STUDIES ON POPULATION DENSITY AND BIOMASS DYNANICS OF SCIRPUS MARIQUETER

本文研究了上海市南汇县东海农场海堤外侧滩涂上海三棱藨草种群的密度动态、高度生长动态、生物量动态以及它们之间及其与环境之间的相互关系。研究结果表明:在环境条件相对稳定的地带A和B内,海三棱藨草种群的高度、高度生长和生物量在生长期内符合Logisfis增长。种群生物量动态与密度动态可分为3个阶段,其中阶段Ⅱ符合Yoda等提出的-3/2自疏定律。地带B为海三棱藨草种群生长的最适地带。地带C内生境条件极不稳定,种群的数量动态变化亦相当剧烈。在不同环境条件下,密度制约因素和非密度制约因素对种群数量动态的相对作用是不同的。在环境条件较稳定的生境中(地带A和B),密度制约因素是决定种群数量动态的主要因素;在环境条件变化剧烈的生境中(地带C),非密度制约因素是决定种群数量动态的主要因素。

This study was carried out at a seabeach salt marsh in Donghai Farm, Nanhui county, Shanghai. Population density, height growth and biomass of Scipus mariquetep, as well as the interrelationships between them and with the environmental conditions, were described. The research results showed that at the relatively stable habitats(zone A and B), the population density, height growth and bi- omass dynamics during the growing season was in accodance with logistic growth. Three phases could be recognized for the population density and biomass dynamics, and the -3/2 power law of natu- ral thinning was applicable to the populations in phase Ⅱ. Zone B was the optimum area for population growth of Scirpus marzqueter. The habitat conditions at the zone C were quite unstable and the population density and biomass dynamics was fluctuated drastically. Under different environmental conditions, the relative roles of de- nsity-independent and density-dependent factors on population dy- namics differed greatly. At the relative stable habitats(zones A and B), the density-dependent factors were the major factors to deter- mine population dynamics, while at the unstable habitat (zone C), the density-independent factors were the major factors.