STUDIES ON THE DIGGING ACTIVITIES AND EXPLORATION ABOUT THE METHOD OF NUMBER ESTIMATION OF PLATEAU ZOKOR

In 1985, at Haibei Alpine Meadow Ecosystem Research Station of Menyuan county, Qinghai Province, the relationship between the annual rhythms in digging activities of the Zokor and the environmental factors of climate, plants biomass of underground part and phenology were studied. The daily rhythms of digging activities in different seasons were analysed and compared. In accordance with the activity rules, we approach the possibility to estimate the Zokor number by soil mounds. 1. The starting and the stopping of digging activities had something to do with the degrees of thawing and freezing of the earth surface and was indirectly affected by temperature. 2. The weight of soil pushed up above the surface by Zokor during the green up period 89 days was 1024 kg per Zokor, account for 30.75% of the annual digging quantity and exuberance period (82 days) 6.32%, withering period (57 days)62.92%. 3. The digging activities occurred day and night, but more frequent at night than in the daytime, and hardly occurred during the hot summer days. Two peaks were found, one was almost simultaneous with the sun rising; the other varied slightly with the different seasons.But generally, they occurred at about midnight. 4. The digging quantity had close relations with special weathers. It could be checked by snowfall, snows and more intense irradiation of sunlight. Frequent activities occurred after a cloudy day, a mild or fine rainy day. 5. The size of mound was affected by the degree of thawing, freezing of earth surface as well as the age structure of the Zokor population etc. 6. During the two frequent digging seasons spring and autumn, the method of estimating the numbers of the Zokor population by soil mounds is simple and reliable.