摘要
应用 1 984、2 0 0 1、2 0 0 2年在内蒙古锡林郭勒盟多伦县的野外调查样方资料 ,采用群落盖度变化 ;植物种在样方中出现频度的变异性、生物量的变异性和 β多样性指数作为指标 ,综合的分析沙漠化过程不同阶段的稳定性。结果表明 :( 1 )沙漠化过程不同阶段盖度的下降比例并不是均匀的 ( 35 %→ 2 5 %→ 1 5 %→ 5 %→ 0 % ) ,这种不均匀性可以反映出演变过程中不同阶段的保守性和易变性 ,下降比例越小 ,说明这一阶段越保守 ,从而也越稳定 ;( 2 )不同阶段 1 m2样方内所包含的物种数量 ,以及物种数量的变异系数 ( 0 .31→0 .34→ 0 .64→ 0 .67)反映了演变的不均匀性 ;( 3)不同阶段 1 m2 样方内生物量的变异系数 ( 0 .5 0→ 0 .49→0 .66→ 0 .64)反映出演变的不均匀性 ;( 4 )通常 β多样性指数被表示为群落间相似性指数 ( 0 .81→ 0 .60→0 .32→ 0 .0 0 ) ,沙漠化过程中相邻两个阶段的相似性越高 ,说明稳定性也越高。以上几个指标反映的趋势是一致的。恢复性与稳定性正好相反 ,越稳定的阶段越不容易恢复 ,反之 ,越容易恢复。
By using the sampling data surveyed in Duolun County of Xilingole League of Inner Mongolia in 1984. 2001 and 2002 respectively, the variability and recovery of grassland desertification process in different stages were studied and analyzed Comprehensively adopting the changes of Community coverage in different stages of grassland desertification process, variability of species occurring frequency in sampling plots、variability of biomass and β diversity index reflecting the variability degree in different stages as the indexes. The results showed that: (1) the decline of vegetation coverage was the most object changing in desertification process, but the decling ratio was uneven in different stages (35%→25%→15%→5%→0%). This unevenness reflected the conservativeness and changeability in different stages of evolution process. The less the ratio declined, the more conservative the stage was. Thereby it reflected that this stage was more stable, otherwise, it would be more unstable. (2) The species numbers appeared in 1m^2 quadrat in different stages and its variation Coeffieient (0.31→0.34→0.64→0.67) reflected the evolution unevenness. (3) The variation coefficient of biomass (0.50→0.49→0.66→0.64) in 1m^2 quadrat in different stages also reflected the uneverness. (4) The higher the similarity between the two neighbouring stages in desertification process was, the more the stable the stage was. Usually, β diversity index was indicated as similarity index of inter-community (0.81→0.60→0.32→0.00). The tendency reflected by four indexes mentioned above was in coincidence. It was found that two remarkable points should be mentioned after analyzing the stages of desertification process: the first one is that the stability presented a declining tendency along with the intensified desertification process; the second is that in desertification process the variation among each stages before Light stage (A.frigida stage) was small, but the similarity was high. There was really a leap forward chang
出处
《生态学报》
CAS
CSCD
北大核心
2003年第12期2545-2549,共5页
Acta Ecologica Sinica
基金
国家重点基础研究发展规划资助项目 (G2 0 0 0 0 4870 4)~~
关键词
沙质草原
沙漠化过程
稳定性
恢复性
grassland
desertification process
stability
resilience
