Study On Species Diversity And Population Distribution Of Dactylis Glomerata L. At Different Elevations In Talbahatai Mountain

In order to understand the population distribution characteristics of D.glomerata in different elevation areas of Talbahatai Mountain under natural growth conditions,the quantitative characteristics,species diversity and distribution pattern changes of the community population in 1300 m,1500 m,1700 m and1900 m grasslands were compared and analyzed.To explore the changing rule of D.glomerata population in the course of adapting to natural environment can provide scientific basis and foundation information for the utilization and protection of germplasm resources of D.glomerata population in Talbahartai Mountain.The main results are as follows:（1）There were 52 species belonging to 17 families,including 12 species of Compositae,8 species of Gramineae and less than 5 species of other families.The significant value of D.glomerata was the largest in four elevation areas,but the important values of other species varied significantly in 4 altitude sections,without obvious regularity.（2）The community height,coverage,density and aboveground biomass of D.glomerata community showed some differences with the elevation gradient,but did not show certain regularity.The community height increased first and then decreased with the increase of altitude.The elevation of 1500 m was significantly higher than that of other areas,and the lowest was at 1900 m With the change of elevation gradient,there was no significant difference in community coverage between different elevations（p>0.05）,and the community coverage was more than 85%.The community density at 1300 m above sea level was significantly higher than that at other elevations,showing the lowest trend of decreasing first and then decreasing with elevation.There was a consistent trend between community biomass and community density,and the maximum value was 1209.82 g·m^-2at 1700 m,but there was no significant difference in each elevation area.The proportion of D.glomerata in the community increased gradually with elevation,and reached its peak at 1700 m,then decreased slightly at 1900 m.（3）Theαdiversity index showed a certain regularity with the elevation,the Shannon-Weiner index decreased first and then increased with the elevation,and the common species among the meadows in the mountain shrub meadow had the least common species,and the variation ofαdiversity index showed the tendency of decreasing at first and then increasing with the elevation.The similarity among communities was the smallest,theβdiversity index was the lowest in mountain meadow,the number of common species among species was more,and the similarity among communities was the greatest.There is a negative correlation between elevation and diversity index,and the increase of elevation is accompanied by the decrease of diversity index.（4）Application of diffusion coefficient,intensity of population distribution pattern and geostatisticswere used to study the distribution pattern of D.glomerata population at different elevations.The distribution patterns of different sampling areas were aggregated at 1300 m～1500 m and 1900 m.At different sampling scales,all samples are clustered distribution,and only at 1700 m the sampling scale is12800 cm².The spatial pattern of the data was studied by using Arc GIS 10.0 software.The results showed that the population of the four sea level D.glomerata showed an aggregate distribution pattern as a whole,and there were more than three aggregation patches,and the spatial small-scale pattern was obvious.It can be seen from the spatial pattern of the four independent squares at the altitude that,except at 1700 m,the two plots tend to be uniform,the other independent squares at sea level all show strong aggregation,and most of them form more than three aggregative plaques.