不同干扰强度高原鼠兔对高寒草甸土壤温室气体通量变化的影响

Effects of different plateau pika disturbance intensities on greenhouse gas fluxes in alpine meadows

高原鼠兔通过取食植物、排泄粪尿及掘土等行为对土壤理化性质及土壤微生物产生广泛干扰,进而可能会影响高寒草甸土壤温室气体排放。本研究选择高密度组(H)、低密度组(L)、对照组(CK)3种鼠兔干扰强度的高寒草甸为研究对象,揭示温室气体排放速率对不同高原鼠兔干扰强度的响应规律及主要调控因素。结果表明,H组高寒草甸土壤CO_(2)排放速率为596.66 mg·(m^(2)·h)^(-1),显著低于CK组的695.45 mg·(m^(2)·h)^(-1)(P<0.05)。高原鼠兔干扰强度、地上生物量、土壤pH和土壤含水量是影响CO_(2)排放速率的主要调控因素。H组高寒草甸CH_(4)吸收速率为-43.46mg·(m^(2)·h)^(-1),显著低于L组的4.92mg·(m^(2)·h)^(-1)(P<0.05),H和L组高寒草甸N_(2)O排放速率分别为8.03、-2.39μg·(m^(2)·h)^(-1),均显著高于CK组的-16.69μg·(m^(2)·h)^(-1)(P<0.05)。土壤硝态氮和铵态氮含量、pH和含水量是影响CH_(4)吸收和N_(2)O排放的重要因素。因此,高原鼠兔干扰强度是影响温室气体排放速率的因素之一,进一步研究高原鼠兔对高寒草甸土壤温室气体排放速率的影响具有重要意义。

Herbivore activities influence the rate of greenhouse gas emissions in grasslands.The plateau pika(Ochotona curzoniae)affects soil greenhouse gas emissions in alpine meadows through extensive disturbance of soil physicochemical properties and soil microorganisms by mowed plants,excretion of feces and urine,and digging up of the soil.This study set three alpine meadows as high-density(H),low-density(L),and control(CK)groups to compare the differences in greenhouse gas fluxes under different pika disturbance intensities.The effects of different pika densities on the soil’s physicochemical properties and greenhouse gas fluxes were analyzed.The CO_(2) emission rate of alpine meadow soil in group H was 596.66 mg·(m^(2)·h)^(-1),which was significantly lower than that of group CK at 695.45 mg·(m^(2)·h)^(-1)(P<0.05).The CO_(2) emission rate was primarily influenced by the disturbance intensity of pikas,aboveground plant biomass,soil pH,and water content.The CH_(4) uptake rate in alpine meadows was significantly higher in group H than that in group L[-43.46,4.92 mg·(m^(2)·h)^(-1);P<0.05].The N_(2)O emission rate was significantly higher in both groups H and L[-8.03μg·(m^(2)·h)^(-1)and-2.39μg·(m^(2)·h)^(-1),respectively]than that in group CK[-16.69μg·(m^(2)·h)^(-1)](P<0.05).The CH_(4) and N_(2)O fluxes were mainly affected by soil nitrate nitrogen content,ammonium nitrogen content,pH,and water content.The findings indicate that the intensity of plateau pika disturbance is one of the factors affecting the greenhouse gas emission rate.Additionally,it is important to study the effect on the greenhouse gas emission rate of alpine meadow soils.