放牧强度对荒漠草原土壤含水量及群落特征的影响

Effects of Grazing Intensity on Soil Water Content and Community Characteristics in Desert Steppe

以内蒙古高原短花针茅荒漠草原为研究对象,随机设置了不放牧、适度放牧和重度放牧3个放牧处理,每个处理3次重复,对不同放牧处理下土壤含水量以及群落特征进行测定。结果表明,在不同放牧条件下,随着放牧强度增大,土壤含水量会发生明显的变化,土壤含水量在0~10cm和10~20cm土层逐渐下降,依次表现为不放牧>适度放牧>重度放牧,在20~30cm土层呈现先上升后下降趋势,在重度放牧处理下最低;放牧显著降低了植物高度、盖度和地上生物量。适度放牧下多年生禾草和一二年生草本的重要值增加,群落α多样性指数符合“中度干扰假说”,Simpson指数和Shannon-wiener指数均在适度放牧下最高;土壤含水量和群落特征如地上生物量、生物多样性密切相关。综合来看,适度放牧最有利于荒漠草原的可持续发展利用。

The effects of grazing intensity on the soil water content and plant community characteristics of Stipa breviflora desert steppe in Inner Mongolia Plateau were explored by setting three treatments(non-grazing,moderate grazing,and heavy grazing)with triplicate in each treatment.The results showed that the soil water content was significantly changed under different grazing conditions.With the increase of grazing intensity,the soil water content gradually decreased in 0~10cm and 10~20cm soil layers,the highest in non-grazing treatment,followed by moderate grazing and heavy grazing treatments.In addition,the soil water content increased first and then decreased in the 20~30cm soil layer with the lowest under heavy grazing condition.Grazing also significantly reduced plants’height,coverage,and aboveground biomass.The important value of perennial grasses and annual and biennial herbs increased under moderate grazing conditions with maximum Simpson and Shannon-Wiener indexes.Meanwhile,theαdiversity index of the community conformed to the“Moderate interference hypothesis”.Furthermore,the soil water content was closely related to plant community characteristics,such as aboveground biomass and biodiversity.In summary,moderate grazing is optimum for the sustainable development and utilization of desert steppe.