干旱区生态环境知识资源中心

The amount of litter and its type can affect seedling establishment and species richness in plant communities. However, little is known about the species-specific effects of litter, especially in the presence of a competitor. We conducted a common garden test to examine the combined effects of competition and plant litter from conspecific versus heterospecific species on the emergence and early growth of the invasive plant Flaveria bidentis and the co-occurring native plant Amaranthus retroflexus. The litter of native species reduced the rate of seedling emergence of F. bidentis; this effect was stronger in the presence of a competitor. Litter addition reduced the seedling emergence rate of A. retroflexus, but had a neutral to positive effect on its early growth, indicating a clear species-specific pattern. Litter addition, combined with interspecific competition, facilitated growth of A. retroflexus; this species seemed to perform better in changing soil conditions than did F. bidentis. Consequently, a habitat-specific adaptation might be involved in this interspecific plant-soil feedback. Our results contribute our understanding of how to suppress F. bidentis in disturbed sites without herbicide application. Manipulating litter cover could be used to manage this invader; such addition would either affect emergence or the belowground competition for soil resources.