典型草原啮齿动物密度与牧草损失量的关系

Relationship of rodent densities with forage loss in typical steppe

研究啮齿动物密度对牧草损失量的关系,对于计算草地经济损害水平至关重要,可以为草地畜牧业管理决策提供指导。本研究于2012-2016年,在锡林郭勒典型草原(东乌珠穆沁旗),应用标志重捕法和样方法对啮齿动物密度以及9月份植物地上生物量进行调查,用啮齿动物密度及其日食量来估算鼠类对牧草的损害程度,确定牧草损失量。研究结果表明:(1)啮齿动物密度与牧草损失量的最佳拟合曲线是三参数S型曲线,为:Loss=k/(1+e^(a-rdensity));(2)当啮齿动物密度>906个标准鼠单位/hm^2时,牧草产量发生最大损失(牧草产量损失比=23.30%);(3)根据所拟合的曲线,得出该类型草地啮齿动物对牧草损害的危害阈值为174个标准鼠单位/hm^2。

Study of the relationship of rodents density with forage loss is essential both for the calculation of economic inju- ry levels （EIL） and for management decisions. An experiment was conducted to investigate rodent density and aboveground biomass of forage in typical steppe in Inner Mongolia each autumn from 2012 to 2016. Rodents were live-captured and for- age biomass was measured with a quadrat method. Rodent damage was estimated using the density and daily intake of rodents to determine forage loss. The results suggested that ： （ 1 ） A three-parameter sigmoid curve modeled the relation between rodents density and forage loss, which was better than that of other models, and the formula was ： Loss = k/ （ 1 ＋ ea-rdensity） ; （2） The largest forage loss （ =23.30% ） occurred when the rodents density was greater than 906 standard rodent units per hectare; （3） Based on our optimal model, the damage threshold was 174 standard rodent units per hectare in typical steppe.