Facts from a Year of Drought: Forage Competition between Livestock and the Mongolian Pika (<i>Ochotona pallasi</i>) and Its Effects on Livestock Densities and Body Condition

Burrowing small mammals in grasslands have long been regarded as pests because they compete for forage with livestock and reduce the forage availability for livestock by destroying pastures through their intensive digging activity. In order to investigate forage competition between the Mongolian Pika (Ochotona pallasi) and livestock an exclosure experiment consisting of four different treatments was set up. The treatments were: 1) accessible only for pikas, (only pika) 2) accessible only for livestock, (only livestock) 3) accessible for both herbivore groups (pika & livestock) and 4) no grazing (no grazing). During the investigation period all requirements for forage competition, namely overlap of habitat use, overlap of forage use, and forage scarcity were met. The results of the exclosure experiment show that in the year of this study pikas consume a higher percentage of the vegetation than livestock does. Therefore, pikas are competitively superior to livestock. Nevertheless, both groups can coexist as they have access to mutually exclusive forage resources. For pikas this resource probably is the forage below the biting height of livestock, whereas livestock can reach forage on pastures far away by migration.