不同刈割强度下羊草草甸草原生物量与植物群落多样性研究

A study on the diversity and aboveground biomass in a Leymus chinensis meadow steppe community under different cutting intensities

以内蒙古高原南缘羊草草甸草原为对象,设5个利用梯度,即不刈割、留茬2,5,10和15cm,研究了连续刈割处理3年后羊草草甸草原生物多样性与地上生物量的变化规律。结果表明,群落中羊草地上生物量随刈割强度的增大而减小(P<0.05);群落生长量为不刈割处理显著高于留茬10和15cm(P<0.05);多样性指数(Margalef、Simpson、Shannon-Wiener和Pielou指数)随刈割强度的增大而增大(P<0.05)。羊草相对密度随刈割强度的增大而减小,糙隐子草和委陵菜属植物随刈割强度增大而增大(P<0.05)。相关分析表明群落多样性指数与地上生物量之间呈"单峰型"曲线关系,而与草原优势物种——羊草的地上生物量呈显著负相关关系(P<0.05)。

The effects of cutting intensity on the biodiversity and aboveground biomass of Leymus chinensis meadow steppe were studied at the southern margin of the Inner Mongolian Plateau.Five stubble heights （2,5,10,15 cm,and non-cutting） were designed to represent different cutting intensities.The aboveground biomass of the dominant species,L.chinensis,was significantly reduced by an increase of cutting intensity （P0.05）.The height of aboveground parts in the non-cutting treatment was significantly higher than those under the 10 and 15 cm cutting treatments （P0.05）.The diversity indexes （Margalef index,Simpson index,Shannon-Wiener index and Pielou index） increased with an increase of cutting intensity （P0.05）.The relative density of L.chinensis decreased with an increase of cutting intensity,while that of Cleistogenes squarrosa and Potentilla,increased.Correlation analysis indicated that there was a ＂single peak＂ curve between diversity index and aboveground biomass in this steppe community.Diversity index was significantly negatively correlated with the aboveground biomass of L.chinensis.