Analysis on Dynamic Life Table of Natural <I>Haloxylon ammodendron</I> at Seedling Stage in the Southeastern Marginal Zone of the Junggar Basin

Abstract

Haloxylon ammodendron inhabits along the southeastern marginal zone of the Junggar Basin in Xinjiang. In this paper,the developmental processes of natural population of H.ammodendron are studied with the means of the dynamic life table.The results show that there are separately two peak stages of rapid drop of survival rate and high mortality rate of H.ammodendron seedlings.In which the mortality rate of H.ammodendron seedlings at the first stage from April 1 to May 1 is as high as 69.9%.At the latter stage from June 15 to July 15,the high mortality rate is caused by disadvantageous climatic conditions and eating by animals in the early growth season, but it is caused by the decrease of moisture content in shallow soil layer.The survival curves of H.ammodendron seedlings belong to the pattern of DeeveyⅢ,which indicates that the mortality rate of H.ammodendron plants is high at the early seedling stage,but the early seedling stage is a key period for the natural regeneration of H.ammodendron seedlings.The study results of dynamic life table at the seedling stage can provide the scientific basis for the natural regeneration of H.ammodendron seedlings and working out the management measures.