LAUSR

BACKGROUND AND AIMS Previous studies investigating plant-plant interactions have focused on plant growth, context dependence, and shifts in interactive outcomes. However, changes in functional traits in the context of interactions are inadequately explored; especially, few studies have focused on the effects of interactions on the plasticity of functional strategies. METHODS We conducted a four-year removal experiment for xeric shrub Artemisia ordosica and perennial graminoids (PGs) in the Mu Us Desert, Northern China. Soil nutrient content, biomass, and twelve functional traits related to plant morphology and nutrient status were measured for the shrub species and a dominant PG species (i.e. Leymus secalinus) in the presence and absence of shrubs and PGs. KEY RESULTS From the results, shrubs affected the functional traits of L. secalinus, reducing leaf dry matter content and increasing plant height, which probably promoted the functional strategy of L. secalinus towards a more resource-acquisitive and competitive strategy. In contrast, when the shrubs were affected by PGs, they shifted towards a resource-conservative and stress-tolerative strategy, by increasing leaf dry matter content and decreasing specific leaf area. Moreover, the shrub species relied more on internal nutrient recycling (higher nitrogen resorption efficiency) rather than on external nitrogen uptake under nitrogen competition; instead, L. secalinus tended to exhibit higher external nitrogen uptake from soil during nitrogen shortages. CONCLUSIONS This study indicated that the functional strategies and nutrient cycling of the shrub species and the dominant PG were altered by each other. The shifts in functional traits may help plants to coexist in the community for a relatively long time. Our findings highlighted that interspecific interactions alter plant functional strategies and provided new insights into community assembly and succession mechanisms in a revegetated shrubland for ecological restoration of drylands.