Population Density Fluctuation Feature of Brandt's Voles during the Growing Season of Vegetation

The seasonal fluctuation feature of Brandt's voles' population density during the growing season of vegetation was analyzed according to the date obtained by capture-neatly and marking-recaptured methods from 1984 to 2004.The results show as follows: 1.During the growing season of vegetation,there were significant differences of density dynamics among different years,e.g.the increase rate and autumn decline rate in high density year were 137.39% and 34.09% which were lower than the values of other years at 206.63% and 37.20%,respectively.2.For a given year,the population density in Spring was significantly correlated with the peak number of voles(r=0.643,P0.05)and the number of winter survival voles(r=0.769,P0.05).3.A significant correlation was detected between yearly and seasonal population density fluctuations,i.e.yearly population density was impacted by the seasonal fluctuations.The seasonal patterns usually exhibited a single-peak feature and the peak appeared during July to August.There was no distinct peak of population density but an increasing trend in high density year.