Seedlings of the semi-shrub Artemisia ordosica are resistant to moderate wind denudation and sand burial in Mu Us sandland, China

摘要

Sand movement is a common stress for plants in dune ecosystems. Seedlings in such an environment often experience various degrees of denudation or burial. A field experiment was conducted with Artemisia ordosica, a dominant semi-shrub species in Mu Us sandland, China, to test seedling survival and growth under different degrees of denudation and burial. Seedlings from two cohorts with height of 5.0 +/- A 0.02 cm (S1) and 9.3 +/- A 0.09 cm (S2) were selected and randomly subjected to three denudation treatments (2.5, 5, and 10 cm), five burial treatments (2.5, 5, 7.5, 10, and 15 cm), or a control. S2 seedlings had a higher survivorship than S1 seedlings, especially under severe denudation (10 cm) and complete burial (5 cm in S1; 10 cm in S2). Seedling survivorship was unaffected by moderate burial (< 5 cm in S1; < 10 cm in S2) or denudation (< 10 cm), but it was significantly reduced under complete burial or severe denudation. Seedling growth in leaf area, height, and biomass only declined in severe denudation or complete burial. Seedling burial led to higher biomass investment in shoots, while the reverse was the case in denudation. The results indicate A. ordosica is highly tolerant to moderate burial and denudation, showing adaptive responses that likely increase survival. Differences in responses between seedling cohorts suggest that large seedling size is beneficial for successful establishment in sandy environments and measures to prevent severe denudation and burial of recently germinated seedlings are necessary in attempts to restore steppe vegetations.