Find in Library

Invasive and native plants can coexist in the same habitat; however, the decomposition process may be altered by the mixing of invasive and native leaves. Heavy metal contamination may further alter the co-decomposition of both leaf types. This study evaluated the effects of two concentrations (35 mg·L⁻¹ and 70 mg·L⁻¹) and three types (Pb, Cu, and combined Pb + Cu) of heavy metal contamination on the co-decomposition of leaves of the invasive tree <i>Rhus typhina</i> L. and the native tree <i>Koelreuteria paniculata</i> Laxm, as well as the mixed effect intensity of the co-decomposition of the mixed leaves. A polyethylene litterbag experiment was performed over six months. The decomposition coefficient of the two trees, mixed effect intensity of the co-decomposition, soil pH and enzymatic activities, soil bacterial alpha diversity, and soil bacterial community structure were determined. A high concentration of Pb and combined Pb + Cu significantly reduced the decomposition rate of <i>R. typhina</i> leaves. A high concentration of Pb or Cu significantly reduced the decomposition rate of the mixed leaves. In general, <i>R. typhina</i> leaves decomposed faster than <i>K. paniculata</i> leaves did. There were synergistic effects observed for the co-decomposition of the mixed leaves treated with combined Pb + Cu, regardless of concentration, but there were antagonistic effects observed for the co-decomposition of the mixed leaves treated with either Pb or Cu, regardless of concentration. A high concentration of Pb or Cu may increase antagonistic effects regarding the co-decomposition of mixed-leaf groups. Thus, heavy metal contamination can significantly affect the intensity of the mixed effect on the co-decomposition of heterogeneous groups of leaves.