[Succession pattern of artificial vegetation community and its ecological mechanism in an arid desert region].

Focusing on the artificial vegetation protection system of the Shapotou section of Baotou-Lanzhou railway in the arid desert region of China, this paper examined the dynamics of dominant plant species and the succession pattern of artificial plant community in the process of establishing and developing regional artificial vegetation. It also studied the driving force and the ecologically intrinsic mechanism of the community succession. The results demonstrated that the species composition of the artificial vegetation dramatically changed after 40 years of succession, from original artificial plant community of shrub and semi-shrub to artificial-natural desert plant community with annual herb dominated. During the process of succession, the importance values of artificial shrubs, such as Caragana korshinskii and Hedysarum scoparius, decreased and gradually retreated from the artificial plant community, while the naturally multiplied annual herb, such as Eragrostis poaeoides, Bassia dasyphylla, Salsola ruthenica, Chloris virgata and etc., were presented one after another and gradually became dominant. Besides, Artemisia ordosica always played a key role in the community due to its ability of naturally sowing and self-replacement. This type of succession pattern was closely related to the shortage of precipitation resource in this region and the formation of soil crust which inhibited the reproduction of shrub and perennial herb with deep root systems. This study provided a theoretical ground for realizing persistent development of artificial plant community.