Quantitative characteristics and species composition of Artemisia sphaerocephala and A.ordosica communities in the Ulanbuh Desert
乌兰布和沙漠沙蒿与油蒿群落的物种组成与数量特征

Artemisia sphaerocephala and A. ordosica communities are all typical vegetation types which play an important ecological protection role in desert areas. Understanding their distribution, species composition and quantitative characteristics is conducive to desertification control. Research results showed that A. sphaerocephala and A. ordosica communities were typical desert vegetation widely distributed in the Ulanbuh Desert, A. sphaerocephala communities were mainly distributed in the central east, northeast and south of the Ulanbuh desert, while A. ordosica communities only distributed in the east, northeast and southeast of the Ulanbuh Desert. Both A. sphaerocephala and A. ordosica communities in the Ulanbuh Desert can be classified into eight types of communities: A. sphaerocephala, A. ordosica, A. sphaerocephala - A. ordosica, A. sphaerocephala - Psammochloa villosa, A. ordosica - Nitraria spp., A.sphaerocephala - Hedysarum scoparium - Calligonum mongolicunl, A. sphaerocephala and A. ordosica concomitant communities. Species composition of A. sphaerocephala and A. ordosica communities was relatively simple. A. sphaerocephala communities consist of 22 species belonging to 9 families of 21 genera; and A. ordosica communities comprise 37 species belonging to 10 families of 35 genera. A. sphaerocephala and A. ordosica communities mainly are dominated by herbs which accounted for more than 70% of total species number. The Simpson and Shannon diversity and Pielou eveness index of A. sphaerocephala and A. ordosica communities were large, which means larger species diversity. The species richness, individual number per unit area, coverage, the Simpson and Shannon diversity index of A. ordosica communities were obviously larger than those of A. sphaerocephala communities, while its community similarity was significantly lower than that of A. sphaerocephala, which revealed that A. ordosica communities had a more abundant species composition, diversity and community structure, and was worthy of protection and artificial construction. These findings may provide an important theoretical basis for protection and artificial construction of A. sphaerocephala and A. ordosica communities, and can support desert control in the Ulanbuh Desert.