天山中部天山云杉林土壤种子库年际变化

Abstract

Species composition,inter-annual variations of seed density,similarities at different intervals of the species composition in soil seed bank were examined using germination method in the P.schrenkiana near mature forest(101—120a) and mature forest(121—160a) from 2004 to 2011.Total 87 species which belonged to 29 families and 70 genera were identified from soil seed bank.Among them,2 kinds of tree plants,2 kinds of shrub plants,and 83 kinds of herb plants were concluded.Additionally,the density of herb seeds in soil seed bank was far greater than that of woody.There were only 6 constant species among 8 sampling years of soil seed bank.There was a huge inter-annual variation which was not synchronous in the seed density of soil seed bank and the seed density of P.schrenkiana.The maximum value of density of soil seed bank which appearing in 2009 was(953.75 ± 66.12) seeds/m2,and the minimum value in 2008 was(186.50±20.37) seeds/m2.The highest value of seed density of P.schrenkiana reached to(584.50±53.58) seeds/m2 in 2006,while the lowest was only(0.25±0.26) seeds/m2 in 2005.Inter-annual variations of species composition in soil seed bank of P.schrenkiana forest had not the similarity.The average of Czekanowski similarity coefficient was 0.344,which showed decrease-increase-decrease trend with the increase of the year's intervals.Species composition and seed density in soil seed bank of P.schrenkiana was not consistency,the differences between inter-annuals were significant,the similarity of species composition was not high.The seed density of P.schrenkiana in soil seed bank which changed in discontinuous was mainly influenced by the production of seed harvests at the year before.The research of inter-annual variation of the soil seed bank could provide scientific basis for forest regeneration,restoration and sustainable management in the Tianshan Mountains.