Effects of plateau pika disturbance levels on the plant diversity and biomass of an alpine meadow

Abstract

AbstractThe plateau pika (Ochotona curzoniae) is known to influence the plant diversity and biomass of the alpine meadow, and it is regarded as a pest. The species has been subject to extensive controls without a clear target density in the Qinghai‐Tibetan Plateau. We investigated the effects of different plateau pika disturbance levels on plant composition, species diversity and biomass. The density of active burrow entrances was used as an index of disturbance levels I, II, III and IV (corresponding to 8, 19, 27 and 39 active burrow entrances per 625 m2). We found that the plant community composition differed with different disturbance levels. The plant replacements were mainly related to associate plants rather than dominant plants. With the increase in the plateau pika disturbance levels, the plant cover decreased, and the plant height first increased and then decreased. The plant evenness index was higher in the levels II and III disturbance conditions, while the plant diversity index and plant richness index were highest in the level IV disturbance condition. The disturbance levels had no effect on the total plant biomass; however, the intermediate disturbance levels (II and III) increased the palatable plant biomass. The total plant biomass was mainly dependent on the unpalatable plant biomass. The total plant biomass showed a positive correlation with the richness index and a negative correlation with the evenness index. The palatable plant biomass showed a positive correlation with the evenness index and a negative correlation with the richness index. These results imply that the intermediate disturbance levels are beneficial to livestock production as they increase the alpine meadow quality, and the higher disturbance level is better for plant diversity conservation in the alpine meadows of the Qinghai‐Tibetan Plateau.