| The plateau zokor(Myospalax baileyi) is one of the dominant subterranean rodents on the Qinghai-Tibet Plateau and it has an important role in alpine grassland ecosystems. Plateau zokor has the closer relationship between the dynamic change of population density and its reproductive characteristics, which is related to the zokors habitat. For clarifying the relationship, and to objectively assess the damage to alpine meadow caused by plateau zokor. The paper selected Mayintan of Zhuaxixiulong township in Tianzhu Tibetan Autonomous County in Gansu Province to study the relationship between seasonal changes of individuals reproductive characteristics and habitat quality under different zokors population density, and the impact of short-term removing plateau zoko on reproductive characteristics and habitat quality. The paper also analyzed the relationship between the plateau zokor population and environmental factors in order to clear influence of environmental factors. Besides,the assessment of damage caused by plateau zokor to alpine meadow in term of production and ecological function were studieed. The results showed:1. There were not significant difference in males and females reproductive performance between two pastures with different population density.The sex ratio of plateau zokor in the low population pasture were greater than that in the high population density pasture in the reproductive peak, but, the sex ratio of high population density were greater than that in the low population density pasture in the initial stage and end stage.There were not significant difference in composition of botany, aboveground and underground biomass and edible herbage yield between two pastures.However,there were significant differences in polysaccharide content of root. Except the depth of zokors foraging in soil(0~20cm), there were not significant difference in soil compaction between two pastures,but, there were significant difference in soil moisture.2. There was no significant difference on reproductive performance of plateau zokor before and after the removing. After removing, there were significant difference on the area of new mounds and edible forage yield, but it was no significant difference on the biomass of aboveground and mounds. Besides, there no were significant difference on soil compaction and soil moisture before and after the removing, howover, it was increased about the ratio of inedible forage.3. There was no significant difference on inter-annual NDVI and bodyweight,pregnancy rate, population density year to year from 2008-2014. With the development of time, the bodyweight of male and female, population density had a positive correlation with NDVI, however, the pregnancy rate had a negative correlation with NDVI. There was not correlation between bodyweight of male and female, pregnancy rate, population density and average annual precipitation,average annual temperature.4. There were not significant difference in aboveground biomass, total coverage,edible forage yield and biomass on the mounds between three paddocks with different population density, there were not significant difference in botanical components and the proportion that new mounds area occupy the total investigated area of paddock. Except the depth of zokor foraging in soil(5~15cm),there were not significant differences in soil compaction between three paddocks.But, there were significant differences in soil moisture in the soil depth(0-30 cm)between three paddocks. The results indicated that the quality of sampled paddock were not significant difference under three zokors population densities in the study area. Moreover, the studying reveled that the size of sampling influenced the assessment of zokors damage to alpine meadow. The appropriate sampling area should be over 0.5 hectare. |
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