高原鼠兔食物资源利用的研究

高原鼠兔(Ochatona curzoniae Hodgson)为青藏高原草场上的重要害鼠。每年都要投入很大的力量进行防治,因之它的生态学研究是非常必要的。草原上的初级生产--绿色植被是如何被高原鼠兔利用的就是一项重要的研究课题。皮南林(1975)曾在快尔玛地区研究过高原鼠兔的食性,并注意到食性与植物多度的关系。

UTILIZATION OF THE FOOD RESOURCES BY PLATEAU PIKA

The food utilization of the plateau pika (Ochotona curzoniae Hodgson) was observed at Haibei Alpinal Meadow Ecosystem Researching Station(Lat. 37°9′-37°5′N, Long.l01°2′-101°3′E). Ten sampling plots of 25 x 25cm² were chosen at random to study the coverage, biomass and number of different plant species, from which the abundance of the species in the meadow were estimated, then the food resources were to be inferred accordingly (Tab.l). The grazing freqencies of the pika to various food were recorded to determine the degrees of utilization and the grazing heights of the pika were measured as well. Then the relative grazing heights were compared (Tab.2). The results of the study were as follows:1. The grazing frequencies of the pika disagree with the abundance of the food resources because the pika utilizes the food resources selectively. The pikas tend to like such food as Elymus nutans, Oxytropis, Poa, but dislike Kobresia. So they play an important role in stablizing the alpine meadow vegetational community.2. With the increase of the experimental density, the food utilization spectrum changed (Fig.l).(1) The food spectrum was generalized. ( 2) The grazing heights were lowered (Tab.2 and Fig.6),both leading to the generalization of the niche,and (3) Changes in the composition of the vegetational community (Fig.5).3. The pika of high density is surely harmful.They destroy the grassland by digging burrows. So the pika of high density should be controlled.