科尔沁沙地不同类型沙地植被恢复过程中地上生物量与凋落物量变化

Dynamics of Aboveground Biomass and Litters in Different Types of Dunes under Vegetation Restoration Processes in the Horqin Sandy Land

植物体生长、死亡及分解是沙地生态系统物质周转的重要环节。以科尔沁沙地流动沙丘、固定沙丘及草地为研究对象,通过对2009—2011年3个生长季各生境植被特征、地上生物量和凋落物的测定,分析了沙地恢复过程中地上生物量和凋落物量的变化趋势和季节动态。结果表明:(1)地表植被存在显著的生境差异,植被盖度、生物量和密度等均表现为草地>固定沙丘>流动沙丘。(2)3类生境地上生物量均存在显著的单峰曲线的季节差异性,其中草地最大生物量分别出现在7月(2009年)和8月(2010、2011年),最大生物量为163.71~247.64g·m^(-2);固定沙丘最大生物量均在2009、2010、2011年7月达到最高,分别为96.13、96.02、102.74g·m^(-2),流动沙丘最高地上生物量为17.48~20.10g·m^(-2),分别出现在7月(2009年和2010年)和9月(2011年)。(3)2009、2010、2011年3类生境中的年最大凋落物量分别为21.0、267.6、370.1g·m^(-2),其中草地和固定沙丘中凋落叶和凋落枝等非立枯有较大比重,流动沙丘凋落物主要为立枯;同时各生境凋落物具有与地上生物量相反的季节特征。

Plant growth,death and decomposition is an important process for matter exchange between plant and soil in sandy land ecosystems.In this study,we focused on 3 different habitats in the Houqin Sandy Land restoration in terms on mobile dune,fixed dune and grassland.Vegetation character,aboveground biomass and litter mass were investigated monthly during the growing season（April to September）from2009to 2011.Meanwhile seasonal variation and dynamics of abovrground biomasses and litters were analyzed among sandy land restoration.The results showed：1）Vegetation character in 3 habitants differed significantly,vegetation coverage,aboveground biomass and plant density were all followed the order grasslandfixed dunemobile dune.（2）Aboveground biomass in3 biotopes all showed a seasonal variation of unimodal curve during the 3 growing seasons.Top biomass in grassland occurred in July of 2009 and August of 2010 and 2011,which ranged from163.71 g·m^（-2） to 247.64 g·m^（-2）.Top biomass in fixed dune occurred all in July during 3 growing seasons and which was 96.13 g·m^（-2）,96.02 g·m^（-2） and 102.74 g·m^（-2）in2009,2010 and2011 respectively.In mobile dune,top biomass ranged from17.48 g·m^（-2）to 20.10 g·m^（-2）and which occurred in September of 2011 and July of 2009 and 2010.（3）Highest monthly mass of litter was 21.0 g·m^（-2）,267.6 g·m^（-2） and 370.1 g·m^（-2） in mobile dune,fixed dune and grassland,respectively.Ratio of shoot in litter was higher than leaf and necromass in grassland and fixed dune,however,which is low in mobile dune.Meanwhile seasonal dynamics for litters in all biotopes were inverse with aboveground biomass.