Mowing plus shading as an effective method to control the invasive plant Spartina alterniflora

Abstract

Plant invasions greatly threaten native biodiversity and ecosystem health, and measures to effectively control and eradicate invasive plants are urgently needed. Spartina alterniflora has invaded large areas of coastal China as well as many other countries, and caused tremendous ecological and economic problems. To develop measures for effectively controlling the invasion of this species, a field experiment was conducted to test the effectiveness of two methods, i.e. mowing alone, and mowing + shading, on suppressing the growth and reproduction of S. alterniflora, with no shading and mowing as the control. The treatments were applied at five different times, i.e. in May, July, August, October, and November of 2013, and measurements were done at the end of the growing season in both 2013 and 2014. Overall, mowing alone could not effectively suppress S. alterniflora at the end of the second growing season (in 2014); instead, this method promoted both the sexual and asexual reproduction of this invasive plant. The mowing + shading treatment, however, highly effectively suppressed the growth and reproduction of S. alterniflora, and no asexual individuals (ramets) or seedlings were observed at the end of the second growing season. The effectiveness of both methods for controlling S. alterniflora was independent of the timing of the treatments in the long term. We propose the use of mowing + shading to effectively eradicate S. alterniflora in China and possibly also in other counties in future, and the selection of the timing for the treatment according to the cost and convenience.