Abstract:

Aims Understanding the impacts of invasive plants on the dynamics of native plants in invaded communities is important for the control of the invasives. Our objectives were to analyze the dynamics of native plants in communities invaded by Solidago canadensis.
Methods We selected native plant communities that had experienced different densities of S. canadensis invasion. Four different invasive stages (based on S. canadensis densities of 0, 5-7, 11-13 and >18 ind. plant∙m^-2) were determined, and 10 plots were randomly distributed in each invasive stage. The plant height, density and aboveground biomass of native species in each plot were measured. The niche breadths and niche overlap coefficients of seven common native species were determined for each plot. Nitrate nitrogen (N), ammonia N, available phosphorus (P), total P and total N of soil were measured, as was total N of plant tissue for the seven common native species.
Important findings Solidago canadensis had more N accumulation than all seven common native species. The invasion of S. canadensis significantly decreased native species richness. With greater intensification of S. canadensis invasion, niche breadth significantly increased for native species with higher plant tissue total N but significantly decreased for native species with lower plant tissue total N, and the average value of niche overlap coefficients of each native species decreased. The invasion of S. canadensis significantly increased soil nitrate N, but decreased soil ammonia N, available P, total P and total N. Results indicated that the ability to accumulate nitrogen determined the dynamics of native plant species when communities were invaded by S. canadensis.

Key words: niche breadth, niche overlap, nitrogen, Solidago canadensis