Effects of Mowing Frequency on the Energy Standing Crops of Major Populations in a Leymus chinensis Steppe of Inner Mongolia
不同频次刈割对羊草草原主要植物种群能量现存量的影响

Through field experiments involving different mowing frequencies for 17 years, we studied variation of the energy standing crops of major populations in a Leymus chinensis steppe of Inner Mongolia. The populations were divided into 3 mowing response groups according to response to mowing frequency: species restrained by mowing, species that benefited from mowing, and species whose distribution remained steady under mowing. The restrained species include L. chinensis, Achnatherum sibiricum, Carex korsinskyi, Allium spp. and other forbs,which decreased in distribution with increasing mowing frequency. The species that benefited include Koeleria cristata and Cleistogenes squarrosa, which increased in distribution with increasing mowing frequency. The tolerant species include Stipa grandis and Agropyron michnoi, which did not change in distribution under mowing disturbance. As far as the relative energy standing crops, all but L. chinensis gradually declined in distribution with increasing mowing frequency; other restrained species did not change in distribution, while the species that benefited and those whose distribution was steady increased with increasing mowing frequency. Successive mowing also influenced the caloric values of some species but the variation was less than 10%.