Differences of tolerance to simulated leaf herbivory in native and invasive tall form Spartina alterniflora populations: Effects of nitrogen availability

Rapid evolutionary changes in invasion-related ecological traits of alien plants are receiving considerable attention in current ecological research. Tolerance to herbivory is of particular interest because of the potential for using biological agents to control the spread of invasive plants. In this study, we compared herbivory tolerance in six populations of tall form Spartina alterniflora: three from its introduced range in Jiangsu Province, China, and three from its native range in Georgia, USA. Plants were grown in a greenhouse and subjected to a full-factorial experimental design with three simulated leaf herbivory levels and two levels of nitrogen availability for 20 weeks. We found that native and invasive tall form S. alterniflora grown under different nitrogen conditions responded to simulated leaf herbivory differently with regard to underground and aboveground biomass and total culm height. Invasive S. alterniflora populations had a greater capacity to compensate for leaf damage than native populations in terms of underground biomass and aboveground biomass, particularly with low nitrogen availability. In addition, invasive S. alterniflora also showed higher compensatory capacity than native plants with regard to total culm height in both nitrogen treatments and with regard to tiller number in the high nitrogen treatment. Elevated nitrogen availability significantly increased the compensatory capacity of underground biomass in native S. alterniflora populations but did not affect any factor in invasive populations. Our results suggested a rapid evolutionary change in herbivory tolerance of invasive tall form S. alterniflora after its introduction to China. Understanding such changes in the tolerance to herbivory between native and invasive populations of alien plants has important implications for improving management efficiency.

► Compared herbivory tolerance in invasive and native tall form S. alterniflora.
► Examined the effect of nitrogen availability on the tolerance of S. alterniflora.
► Suggested evolutionary change in herbivory tolerance of invasive S. alterniflora.