The Influence Of Grazing And Mowing On Grassland Typical Population Spatial Pattern Of Dominant Species

This paper studied the plant population’s spatial distribution pattern by means of the method, which contains both the camera work and theory-method of Geographical Information System. Use of the Ripley’s K function, quantitative analysis of the four kinds of grassland utilization way, from 2012 to 2015 began to grazing and mowing experiment of the CK, grazing, grazing and mowing, mowing sample’s spatial scales in 10 m x 10 m. mowing stubble height is 6 cm and the dominant species of the Stipa krylovii, Leymus chinensis, Cleistogenes squarrosa population’s spatial pattern change and its change rule along with the scale. Using Monte-Carlo random simulation method (Monte-Carlo) estimate the confidence limit of h(t). Was studied using different ways of three kinds of the influence of population spatial pattern of dominant species and their population density change under different grazing and mowing conditions. And further to the Stipa krylovii, Leymus chinensis, Cleistogenes squarrosa population’s rough implicit grass within the life cycle characteristics, ecological adaptation strategies and community based on the interaction between plants, the mechanism generating and maintaining these patterns was discussed and providing a scientific basis for the rational use of grassland. The results showed that:1. The Stipa krylovii population aggregation degree significantly in the scale of the 0.50-3.70 m of the mowing plots was higher than that of the enclosure and grazing plots. The S. krylovii population aggregation degree significantly in the scale of the 0.60-3.50 m of the grazing and mowing plots were higher than that of the grazing、CK plots. The S. krylovii population aggregation degree in the scale of the 0.70-1.60 m of the grazing plots was significantly higher than that of the CK plots. The effect of mowing on the spatial distribution pattern of S.krylovii population was much more than effect of grazing.2. The Leymus chinensis population aggregation degree significantly in the scale of the 0.80-3.10 m of the grazing and mowing plots were higher than that of the enclosure, grazing and mowing plots. The L.chinensis population aggregation degree significantly in the scale of the 1.00-3.10 m of the grazing plots was higher than that of the enclosure and mowing plots. The L. chinensis population aggregation degree significantly in the scale of the 0-3.10 m of the mowing plots were higher than that of the enclosure plots.It with its own biological characteristics and population pressure on grazing and mowing ecological adaptation strategies are closely related. The effect of grazing on the spatial distribution pattern of L.chinensis population was much more than effect of mowing.3. The Cleistogenes squarrosa population aggregation degree significantly in the scale of the 0-2.90 m of the grazing was higher than that of the enclosure, grazing and mowing, mowing plots. The C.squarrosa population aggregation degree significantly in the scale of the 0-1.80 m of the grazing and mowing plots were higher than that of the enclosure, and mowing plots. The C. squarrosa population aggregation degree significantly in the scale of the 0-1.15 m of the mowing was higher than that of the enclosure plots. This is mainly due to the different selectivity of grazing and mowing. The effect of grazing on the spatial distribution pattern of C.squarrosa population was much more than effect of mowing.4. Grazing and mowing duress caused the change of population spatial distribution pattern. The essence is that their population is breeding a large number of new plant individuals around its parent in order to resisting stress, increasing the population aggregation degree in small scale and changing its form and space distribution state, and to resisting trample, feed intake and mowing.