来自世界其它地区的外来植物入侵一直是让美国西部感到头痛的问题。外来的草本植物不仅把本地植物赶出生态圈 ,增加火灾隐患 ,而且使当地原先优质的牧草质量下降。在近日召开的美国生态学会会议上公布的一项最新研究成果表明 ,只要增播本地草种 ,就有可能恢复美国西部原有的草 Invasion of exotic plants from other parts of the world has been a headache for the western United States. Exotic herbs not only drive native plants out of the ecosystem, increase fire hazards, but also degrade the quality of pasture that was originally native to the area. A recent study released at the recent meeting of the American Ecological Society shows that as long as local grass planting is increased, it is possible to restore the original grass in the western United States