Studies On Dominant Populations Of Desert Rodent Under Different Disturbances

From 2002 to 2008, in the first period of April, July and October, the population quantity and reproduction characteristic of Mid-day Gerbil was particularly studied in four diverse disturbance types in Alashan Desert by trap-day methods. They were:â… .Farmland;â…¡.Rotationally grazed grassland;â…¢.Overgrazed grassland; andâ…£.Forbidden grazing grassland. the analysis of the volatility relationship between the population quantity and reproduction characteristic of Mid-day Gerbil and The dynamic analysis showed that:(1)Many years, the reproduction characteristic were limited by its density, and its sex Ratio,the pregnancy rate,average baby number,reproductive index and male rat testicles reducing rate dropped with the increase of population quantity .However, when the population quantity droopped to the lowest, they will increase again in order to relover their population quantity. (2) The limitation of population density Meriones meridianus,Cricetulus barabensis,Phodopus roborovskii on reproduction characteristic would also disappear when population quantity went up fast, When this happens, the population quantity will break out.(3) The most obvious affected by density is male rat testicles reducing rate in kinds of reproduction parameters, secondly be that the sex Ratio and average baby number, the last is the pregnancy rate and reproductive index, which can break the constraints of its density easily.(4)The limitation of Dipus sagitta population density on reproduction characteristic was smallest, followed by Cricetulus barabensis , Phodopus roborovskii and Meriones meridianus. The reproduction ability of Dipus sagitta is lowest, while the population quantity would be most stable; The reproduction ability of Phodopus roborovskii Is the most strongest, while the fluctuation of population quantity would be most dramatic.