Liu Rong-tang

A study on the economic injury level of plateau pika (Ochtona curzoniae) and its control index.

The economic injury level of plateau pika(Ochtona curzoniae) and its control index were studied in the alpine meadow and alpine steppe of Dacha village in Sunan County from 2007 to 2008.The population of plateau pika was positively correlated with the reduction of prairie grass production(aboveground biomass) and the economic losses with the correlation coefficient(r)=0.976 5.The linear regression equation between the number of plateau pikas effective holes(X) and grass production reduction(M) was M=-16.960 3+0.918 0X.The control costs per unit area were 25.05 yuan/hm2 when Clostridium botulinum type C was used for biological control in this area of 1 330 hm2.It was confirmed that the economic injury level of plateau pika was 130 effective holes/hm2 and the allowed economic loss ratio was calculated as 11.2%.the actual density of plateau pika was 510 effective holes/hm2 and the economic loss ratio was up to 32.9% in the research area.