祁连山东缘两种鼢鼠鼠丘形态特征的种间差异

Interspecific difference of mound morphological characteristics of two zokor species in the eastern margin of the Qilianshan mountains

祁连山东缘是甘肃鼢鼠(Eospalax cansus)和高原鼢鼠(E.baileyi)的同域分布区,高密度种群形成的鼠丘显著影响着草地植被和土壤。为明确两种鼢鼠鼠丘形态特征差异及其与环境因子的关系,研究调查了甘肃鼢鼠和高原鼢鼠两个活动高峰期(繁殖期和储食期)的鼠丘形态特征,并分析其差异与土壤、植被因子的相关性。结果发现:两种鼢鼠鼠丘形态特征均存在季节性差异;两个时期中,甘肃鼢鼠鼠丘高度、半径、表面积和体积均显著大于高原鼢鼠鼠丘(P<0.01);高原鼢鼠鼠丘密度显著高于甘肃鼢鼠鼠丘(P<0.05),且高原鼢鼠单只平均造丘数显著大于甘肃鼢鼠(P<0.01);相关性分析发现,繁殖期高原鼢鼠鼠丘形态特征的形成与植被盖度、莎草科地下生物量、杂类草地上生物量及地下总生物量高度相关,而杂类草地下生物量与甘肃鼢鼠鼠丘形态特征的形成高度相关;储食期高原鼢鼠鼠丘形态特征的形成与草丛高度、莎草科生物量及地下总生物量高度相关,而土壤容重与豆科牧草地上生物量与甘肃鼢鼠造丘特征高度相关。可见除自身生物学特性导致的造丘方式不同之外,环境因子也与鼢鼠的造丘方式相关,且存在季节性差异。

The eastern edge of the Qilian Mountains is the sympatric distribution area of Gansu zokor(Eospalax cansus)and plateau zokor(E.baileyi).The mounds formed by high-density populations significantly affect grassland vegetation and soil.In order to clarify the morphological characteristics-related differences between the two zokor mounds and their relationship with environmental factors,we investigated Gansu zokor and plateau zokor mound morphological characteristics during the two activity peaks(i.e.,breeding and food-hoarding seasons)and analyzed the correlation between the soil and vegetation factor-related differences.Our results revealed significant morphology-related differences between the two zokor mounds during the different periods.During the two periods,the Gansu zokor mound height,radius,surface area,and volume were significantly higher than those of the plateau zokor mound(P<0.01).The plateau zokor mound density and average mound number were significantly higher than those of Gansu zokor(P<0.05 and 0.01,respectively).During the breeding season,plateau zokor mound formation morphological characteristics highly correlated with the vegetation coverage,the underground biomass of sedges,the aboveground biomass of forbs,and the total underground biomass,while those of Gansu zokor highly correlated with the underground biomass of forbs.During the storage period,plateau zokor mound formation morphological characteristics highly correlated with the grass height,sedge biomass,and total underground biomass,while those of Gansu zokor highly correlated with the soil bulk density and the aboveground biomass of legumes.In conclusion,beyond the biological characteristics,environmental factors also correlated with the different mound-building modes,and their building modes displayed seasonal differences.