The Study of Economic Benefits in Rodent Pest Control under Different Grazing Patterns in Typical Steppe
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【Author in Chinese】 叶丽娜；
【Author's Information】 内蒙古农业大学， 草学， 2018， 硕士
【Abstract in Chinese】 典型草原不同区域害鼠种类、草地植被类型及草地利用方式均不同,因此,需要根据不同地域的害鼠危害和防治措施,因地制宜的制定合理的防治和经济阈值,对于构建科学的经济效益模型具有很重要的意义。本研究于2012-2017年,在内蒙古锡林郭勒典型草原,采用标志重捕法和样方法研究了按月轮牧、季节轮牧、连续放牧和过牧4种不同放牧方式以及禁牧区下啮齿动物物种组成、捕获量比例、种群密度年度变化以及4种不同放牧方式和禁牧区下植物组成和植物生物量的变化。并用啮齿动物日食量来算出啮齿动物对牧草产量的损失,将啮齿动物密度与牧草产量损失关系进行拟合构建模型,确定4种放牧方式和禁牧区下鼠害防治的危害阈值与经济阈值。本文研究结果表明:1.2012-2017年间在4种放牧方式和禁牧区下共捕获7种啮齿动物,其中布氏田鼠的捕获量最大,黑线毛足鼠为次之。5种处理下共记录16科39种植物,分为禾本科、豆科、菊科和杂类草4类植物。禾本科植物生物量在禁牧区和季节轮牧区为较高。豆科植物生物量在禁牧区为最高。菊科植物生物量在禁牧区和按月轮牧区为较高。杂类草生物量在过牧区为最高。2.通过对5种处理下啮齿动物密度(标准鼠单位/hm~2)与牧草产量损失比关系进行数据拟合,随着啮齿动物密度的增加牧草产量损失也增加,但是啮齿动物密度达到一定程度后牧草产量损失不会再持续增加而达到一个稳定的状态。5种处理下的危害阈值(标准鼠单位/hm~2),按月轮牧最高,季节轮牧次之,连续放牧和过牧为最低。3.五种处理下鼠害防治的平均经济阈值(标准鼠单位/hm~2),季节轮牧方式、禁牧方式和按月轮牧方式下显著高于连续放牧和过牧方式下经济阈值。4.本研究认为季节轮牧方式下能保证牧草质量及产量,经济效益也较高,危害阈值与经济阈值比其他放牧方式高。因此,在该地区典型草原上,采用季节轮牧方式能够保证经济效益又能达到草原可持续利用目的。
【Abstract】 There are great differences betweenrodent pest species,grassland vegetation types and grassland use patterns in different regions of typical steppe.Thus,It is necessary to formulate differentreasonable rodent pest control measures and different economic thresholds on the base of the damage degrees and control measures of rodent pests in different regions.A experiment with four grazing patterns,including monthly grazing(MG),seasonal grazing(QG),continous grazing(CG)and over grazing(OG)and grazing prohibition(CK)was conducted in typical steppe in Inner Mogonlia from 2012 to 2017.Species composition of rodents,catch ratio,annual variation of population density and the changes of plant composition and plant biomass in four different grazing patterns and grazing prohibition were investigated.Rodents were captured with live method.The rodent damage was estimated using daily intake of rodent to determine the loss of forge yield.The relationship between rodent density and forage yield loss was fitted to a model.The damage threshold and economic threshold of rodent control in four grazing patterns and grazingprohibition were determinedby fitting the relationship between rodent density and forage yield loss.The results are as follows:1.During the period of 2012 to 2017,7 species of rodents were captured under four types of grazing patterns and grazing prohibition areas,of which Lasiopodomys brandtii occupied the largest capturedamount,and Phodopus sungorus occupied the second.A total of 39 species of plantsdistributed in16 familywere recorded under the five treatments,which were divided into fourplants types:gramineous,legumes,compositae,and forbs.The biomass ofgramineousplants was higher in the grazing prohibition area and the seasonal grazing area.The biomass of legume was the highest in the grazing prohibition area.The biomass of the compositae was higher in the grazing prohibition areas and in the monthly grazing areas.The biomass of forbs were the highest in overgrazing areas.2.By fitting the relationship between rodent density(standard rat unit/hm~2)and forage yield loss ratios for the five treatments,a sigmoidal curve was obtained.As the density of rodents increases,the loss of forage yield also increases.But when rodent density reaches a certain degree,the forage yield loss will not continue to increase and reach a stable state.The damage thresholds(standard rat units/hm~2)under five treatments were obtained.The monthly rotation grazing was the highest,the seasonal grazing was the second,and continuous grazing and overgrazing were the lowest.3.The average economic threshold(standard rat unit/hm~2)of five treatments under rodent pest control,seasonal rotational grazing,grazing prohibition,and monthly rotation grazing were significantly higher than those under continuous grazing and overgrazing.4.This study concluded that the quality and yield of forage grass can be guaranteed in a great statue with high economic benefit underseasonal grazing.The damage threshold and economic threshold in seasonal grazing were higher than other grazing patterns.Therefore,in the typical steppe region,seasonal grazing pattern can ensure the economic benefits and achieve the purpose of sustainable use of the grassland.