Study On Species Components, Geographical Distribution And Ecology Of Mosses On Microbiotic Soil Crusts In Erdos And Its Neighbor Regions

Through several years of studying in 31 plots in fields, mosses of 17 families, 41 genera and 102 species were found in Erdos region. In the meanwhile, 2 genera and 7 species were newly recorded in china, and 8 species were newly recorded in Inner Mongolia. Mosses of 3 families, 11 genera and 24 species were found in Shapotou, Zhongwei County, Ningxia Hui Autonomous Region, 1 genus and 2 species were newly recorded in china. In Erdos region there were 96% species in steppe which counted for 95% of all the species, only 12 species in desert steppe counting for 11.5% and only 10 species in semi-desert counting for 9.9%.The distributive features of moss species on landscape were mainly as followed: (1) species number became smaller as the rainfall decreased from the east to the west; mesic xerophyre and xerophyre types ecologically came to be the major components, which would decreased in number as the latitude became high. And the biodiversity was consistent with the decreased law of the biodiversity respect to the latitude. (2) The change of habitat diversity (spatial heterogeneity) played a great role on the distribution of species, not only on the large scale but more noticeably on the microhabitat of plots as well. Diverse habitates would produce a higher diversity of species. On habitat scale, the main features were: (1) Environmental humidity, the content of water in soil and number of species were closely related to each other. Species in humid or semi-humid environment were much larger in number than in arid land and larger in bottom of a slope than on the top of a slope. (2) The physical and chemical characteristic of soil (pH value, soil mechanical component, salt content) would directly influence the ,rowth and distribution of moss. (3) The sorts and distribution of vascular plants affected in growth and distribution pattern. The microhabitat accordingly provide refuges for the establishment of mosses, but the ground layers (litter), Which were produced by vascular plants would prevent moss from the distributive below. The habitat difference (including temperature, moisture, and light etc.) was the main reason that leads to the richness difference of bryophyte species.The change of Alpha diversity of bryophytes not only had to do with the change of habitat; but also had much to do with the structural agents, which constituted the habitat. These structural agents contained the synusia structure of community, theIVcanopy density; cover degree and specific composition of vascular plants; the cover degree and distribution pattern of aphyllae. The change of beta diversity of bryophyte was more closely linked with the community structure, with the similarity index of the diversity of similar community structures being obviously higher than that of communities with different structures. Analysis of cover showed that with the increase of the altitude of the slope, the coverage of mosses decreased quickly and that of algae increased slowly. And the cover of moss crusts and that of algae and vascular plants are in insignificant negative relation. With the increase of the fixed-sand time, the cover of mosses and algae tends to enhance, the cover of old fixed dunes moss crusts is thicker than that of algae crusts and the cover of the new fixed dunes is thicker than that of moss crusts .in different zonal vegetation the cover of mosses and algae both decreases with the decrease of average annual precipitation. The fluctuation of annual precipitation in the same area directly affects the cover of mosses and algae.Unit biomass differs in different mosses; and unit biomass of the same specie of moss dramatically decreases with the increase of altitude and the disturbance intensity and the decrease of region precipitation. This was because the change of environment influenced the height and density of mosses, and there were remarkable correlated relationships between the thickness and the height of different species and types of mosses (P<0.01). Binding-sand quantity increased when the fixed sand time prolonged .