Responses to simulated nitrogen deposition in invasive and native or non-invasive clonal plants in China

Abstract

Previous studies suggest that a disproportionately high number of invasive plant species are clonal, and that an increase in N availability often promotes the spread of introduced plants. We tested the hypothesis that greater ability to increase performance in response to the increase in N availability is associated with greater invasiveness in clonal plant species on a regional basis in China, where the potentials for new introductions and for N deposition are high. We compared growth, allocation of mass, morphology, and N use efficiency in six pairs of closely related, widespread species of clonal plants with and without N addition designed to simulate future N deposition of 15 g N m−2 year−1. Within each pair, one species was introduced and invasive in China, and the other was native or in one case introduced but not invasive. Added N increased the final dry mass of species by 10–120 % and the final number of ramets by up to 300 %. However, responses to N did not differ consistently (P > 0.05) between invasive and native or non-invasive species; increase in total mass with added N ranged from being 6 times greater in the invasive species to 3 times greater in the native species in a pair. Results suggest that increased N availability due to deposition in China will favor the spread of some but not all introduced, clonal plant species in China.