黄土丘陵区撂荒群落地上生物量和物种多样性关系

Relationship Between Aboveground Biomass and Species Diversity of Abandoned Community in Loess Hilly Region

研究黄土丘陵区撂荒群落生物量与物种多样性的关系及其影响机制,有助于明确群落演变的机理,可对该区植被恢复重建、群落演替、生物多样性保护和维持具有重要意义。为此,选取该区5个典型撂荒群落,在群落尺度上,分析地上生物量的月动态,重点研究了地上生物量与物种多样性的关系。结果表明:(1)5个撂荒群落地上生物量总体呈上升趋势,月份之间差异极显著,群落生物量由大到小为白羊草(Bothriochloa ischaemum)群落>茭蒿(Artemisia giraldii)群落>铁杆蒿(Artemisia sacrorum)群落>猪毛蒿(Artemisia scoparia)群落>达乌里胡枝子(Lespedeza dahurica)群落;(2)群落地上生物量与物种多样性关系表现为线性增加和线性减少两种形式。猪毛蒿群落中二者呈线性增加。铁杆蒿和白羊草群落地上生物量随丰富度的增加线性增加。白羊草和达乌里胡枝子群落地上生物量随均匀度的增加线性减少。空白生态位的占有和利用、生态位互补效应、种间相互作用是解释二者关系的内在机制,冗余种假说效应可能会导致不显著关系。

The study on relationship between aboveground biomass and species diversity of abandoned old-field community and its mechanism in the hilly region of the Loess Plateau is helpful for understanding community succession process and is also important for vegetation reconstruction,biodiversity protection,and ecosystem health maintenance.In this study,five typical communities were selected to investigate the monthly dynamics of aboveground biomass and its correlation with biodiversity at community scale.The results showed that：（1） the aboveground biomass of the five communities increased from May to September and the difference between different months were significant （p＜0.01）;the community aboveground biomass was the highest in Bothriochloa ischaemum community （375.86 g/m2）,followed by Artemisia giraldii （182.42 g/m2）,Artemisia sacrorum （91.79g/m2）,Artemisia scoparia （76.1 g/m2） communities,the lowest biomass was observed in Lespedeza dahurica （51.49 g/m2） community;（2） linearly positive and negative relations were found with respect to the relationships of aboveground biomass and species diversity index;in Artemisia scoparia community,aboveground biomass increased linearly with increase of species diversity index,while no relation was found in the Artemisia giraldii community;the aboveground biomass increased linearly with increase of Margalef index in Bothriochloa ischaemum and Artemisia sacrorum communities,and decreased linearly with increase of Pielou index in Bothriochloa ischaemum and Lespedeza dahurica communities.Furthermore,the influencing mechanism for the relation between aboveground biomass and biodiversity may result from occupation and utilization of blank niche,niche complementarity,interspecific interactions and competition and exclusion effect.The redundant species hypothesis perhaps resulted in the insignificant relations.