干旱沙区生物土壤结皮对红砂种子定居的影响及作用机制  

Effect of biological soil crusts on seed settlement of Reaumuria soongorica and its mechanism in arid desert area

作　　者：何芳兰 赵赫然[1,3] 王忠文 汪媛艳[3] 李雪娇[1,3] 金红喜 HE Fanglan;ZHAO Heran;WANG Zhongwen;WANG Yuanyan;LI Xuejiao;JIN Hongxi(Gansu Hexi Corridor Forest Ecosystem National Research Station,Wuwei 733000,China;Gansu Linze Desert Ecosystem National Research Station,Linze 734200,China;Gansu Desert Control Research Institute,Lanzhou 730070,China)

机构地区：[1]甘肃河西走廊森林生态系统国家定位研究站,武威733000 [2]甘肃临泽荒漠生态系统国家定位观测研究站,临泽734200 [3]甘肃省治沙研究所,兰州730070

出　　处：《生态学报》2023年第1期304-312,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31860175);中央财政林业科技推广示范项目(2019ZYTG07);甘肃省基础研究创新群体项目(20JR5RA098)。

摘　　要：为了探清干旱荒漠区生物土壤结皮对易漂移性植物种子定居影响及作用机制,以巴丹吉林沙漠南缘结皮前期以及藻类、地衣、藓类阶段结皮为场所,通过人工补充种子与野外长期监测的方法对红砂种子在生物结皮上流失动态、种子宿存微区特征以及种子宿存量与微区面积间的关系等进行研究。结果表明:(1)生物土壤结皮发育过程中,地表枯落物、微坑、龟裂缝、长藓的面积百分比均发生了显著变化,即:枯落物呈现出增大(藻类阶段)—稳定不变(地衣阶段)—减小(藓类阶段)的趋势,微坑、龟裂缝均先增大后减小(峰值在地衣阶段),长藓持续增大。(2)4个阶段的种子流失速度或定居率两两之间存在显著差异,流失速度大小依次为:结皮前期>藻类阶段>藓类阶段>地衣阶段,定居率大小为:地衣阶段>藓类阶段>藻类阶段>结皮前期。(3)生物土壤结皮上定居的种子仅宿存于枯落物、微坑、龟裂缝、长藓上,这4种微区上定居种子数与其面积之间均存在显著正相关关系,其关系均可用二次项y=ax^(2)+bx+c(a≠0)表示,等面积微区内的定居种子数大小依次为:龟裂缝>枯落物>微坑>长藓。因此认为,生物土壤结皮对红砂种子定居的影响主要是单位面积上枯落物、龟裂缝、微坑、长藓等微区面积改变引起的。Biological soil crusts(biocrusts),including the microscopic(algae,cyanobacteria,bacteria,and fungi)and macroscopic(lichen,moss,and microarthropod)organisms,are a common and wide-spread feature of arid and semiarid landscapes throughout the world.They are considered to be essential components of healthy desert ecosystems,of which succession goes mainly from no crust stage(NCS)to algal crust stage(ACS),lichen crust stage(LCS),and moss crust stage(MCS).In order to ascertain how biocrusts influence settlement of seeds drifting easily in arid desert region,the seed dispersal process of Reaumuria soongorica,surface features of some microsites in fixed quadrats deployed on the NCS,ACS,LCS and MCS at the southern edge of Badain Jaran Desert,and relationships of persistence seeds to the above microsites were studied with the method of artificial supplying seeds and long-term monitoring.The results showed that:(1)in comparison with the NCS,the area percentages of litter,micro pit,crack and moss distributing on the dunes changed significantly during the development from ACS to MCS,where the litter showed a trend of increasing(ACS)—stabilizing(LCS)—decreasing(MCS),the pit and crack firstly increased and then decreased(their peak values were at LCS),and long moss increased continuously.(2)A significant difference in the loss speed or settlement rate of R.soongorica seeds on the above quadrats of NCS,ACS,LCS and MCS was observed,in which the loss speed and settlement rate declined in the orders of NCS>ACS>MCS>LCS and LCS>MCS>ACS>NCS,respectively.(3)It was found that seeds settled on the biocrustst only existed in litter,micro pit,crack and long moss;Meanwhile,there was a significantly positive correlation between the number of settled seeds on the four microsites and their area,and their relationships might be expressed by the formula of y=ax^(2)+bx+c(a≠0).Moreover,an obvious difference in the settled seeds on the litter,micro pit,crack and long moss under unit area condition was surveyed,and the seed quantity settled on

关 键 词：生物土壤结皮 红砂 种子扩散 定居过程 

分 类 号：Q948[生物学—植物学]