本研究以伊犁河谷那拉提山地自然保护区不同封育年限草地为对象,对围封条件下退化草地自然恢复过程中草地植被群落特征和物种多样性的变化进行初步分析.结果表明:随着封育年限的延长,不同群落特征对封育年限的响应不同,其他平均高度和生物量封育10年显著大于封育4年(P<0.05),密度封育4年显著大于封育10年(P<0.05),盖度封育4年与封育10年差异不显著(P>0.05).草地植物群落由未封育的杂草为主要物种逐步向以禾草为主要物种的方向演进.随着封育时间的延长物种数从放牧地的15种增加到41种后降低到34种.相关性分析表明群落特征与封育时间的相关性:高度>生物量>盖度>物种数>密度.通过对这些群落特征进行回归分析发现,高度、密度、盖度、物种数在9.7年、3.9年、6.2年、5.9年达到最大.封育第4年多样性指数和丰富度指数最大,但多样性指数封育4年和封育10年差异不显著(P>0.05),丰富度指数封育4年和封育10年差异显著(P<0.05),均匀度指数封育10年最大并且和封育4年差异显著(P<0.05).综合分析得出,那拉提山地草甸最佳封育时间为6~9年.
A preliminary analysis was conducted on the changes in grassland vegetation community characteristics and species diversity during the natural restoration process of degraded grasslands under enclosure conditions in the Nalati Mountain Nature Reserve of the YILI River Valley.The results showed that as the closure period extended,the response of different community characteristics to the closure period varied.The average height and biomass of other community characteristics were significantly higher after 10 years of closure than after 4 years(P<0.05),and the density was significantly higher after 4 years of closure than after 10 years(P<0.05).The difference in coverage between 4 years of closure and 10 years was not significant(P>0.05).The grassland plant community has gradually evolved from uncultivated weeds as the main species to grasses as the main species.With the extension of enclosure time,the number of species increased from 15 to 41 in grazing areas and then decreased to 34.The correlation analysis shows that the correlation between community characteristics and enclosure time is height>biomass>coverage>species number>density.Through regression analysis of these community characteristics,height,density,coverage,and species number reached their maximum in 9.7,3.9,6.2,and 5.9 years.The diversity index and richness index were the highest in the fourth year of enclosure,but the difference in diversity index between 4 and 10 years was not significant(P>0.05).The difference in richness index between 4 years and 10 years of closure was significant(P<0.05),and the evenness index was the highest in 10 years of closure and the difference was significant(P<0.05).Based on comprehensive analysis,the optimal enclosure time for Nalati Mountain Meadows is 6~9 years.