干旱区生态环境知识资源中心

A phytosociological analysis of the loess slopes of the north-central Chinese Loess Plateau revealed a new bryophyte community, the Hilpertio velenovskyi-Didymodontetum tectorum. It can be seen as a geographical vicariant of the already descibed Pannonian loess cliff communities of C. Europe and is typical for the steep slopes in the surrounding of Lanzhou. Here it is an important component of the blackish to greyish microphytic crusts that protect the steep slopes from soil erosion. Character species are Hilpertia velenovskyi, a species strongly associated with loess deposits and the E. Asiatic Didymodon perobtusus and D. tectorum. Additionally, as in the Pannonian communities, Crossidium laxefilamentosum is typical and reported for the first time from China and C. Asia. The new community can be classified within the Grimmaldion fragrantis alliance (Psoretea decipientis class).

The life form and life strategy analyses show clearly that the community is composed of xerotolerant, acrocarpous, short turf-forming ’asexual’ and ’sexual’ colonists. The survival of these species is presumably archieved by asexual diaspores (gemmae), which are present in the diaspore bank, and/or a frequent sporophyte and spore production for habitat maintenance and re-establishing after erosional effects.