Plant invasion affects litter decomposition differently in native and invasive plant conditioned soils

Background and aims

Plant invasion can alter litter decomposition, which is essential for nutrient cycling in terrestrial ecosystems. However, the underlying mechanisms remain unclear. The aim of this study was to explore how plant invasion affects litter decomposition by altering soil properties, litter quality and their interactions.

Methods

We conducted a reciprocal decomposition experiment by decomposing the leaf litter of ten invasive species and ten native species for 180 days in invasive- or native-conditioned soils (conditioned for six months) in China.

Results

Our study revealed interactive effects of litter quality and soil conditioning on litter decomposition, since invasive litter (with lower leaf dry mass content) decomposed faster than did native litter only in invasive-conditioned soils, which was probably explained by a lower fungal richness in invasive-conditioned soils. Additionally, leaves of native, not invasive, species decomposed more slowly in invasive-conditioned soils than in native-conditioned soils.

Conclusions

Our findings indicate that invasive plants can affect litter decomposition by altering litter quality and soil properties, and, thereby, decomposition-by-soil interactions. In particular, conditioning soils with invasive plants resulted in a lower fungal richness, which may explain the slower decomposition of native litter. As such, it is essential to consider the impacts of invasive species on litter inputs and recipient soil communities simultaneously to comprehensively elucidate the effects of invasion on litter decomposition.