By this, the conclusion that shrub and grass vegetation sh ould take a preferential place in vegetation construction of arid and semi-arid regions.

• 据此认为，干旱半干旱区植被生态建设中，坚持以灌木和草本植物为主的原则，才能提高有效水资源的利用效率，取得较好的环保效益。