Heavy drought reduces the decomposition rate of the mixed litters of two composite invasive alien plants

Abstract Compositae family comprises the largest number of species invasive alien plants (IAPs) in China. Two IAPs can co-invade same habitat. Drought alter litter decomposition and soil enzyme activities. This study aims to estimate independent combined effects two composite (Bidens pilosa Solidago canadensis) on activities under drought. A polyethylene litterbags experiment (5 g litters B. pilosa, 5 S. canadensis or an equal proportion per litterbag) was performed. The were treated with a gradient drought, i.e. control, light level drought heavy coefficient determined. co-invasion posed synergistic effect urease activity. mixed had higher rates than canadensis. Urease activity increased droughts, but it decreased Heavy reduced rate pilosa. did not affect litters. Thus, decrease nutrient cycling invasion rather