Relationships between plateau pika (Ochotona curzoniae) densities and biomass and biodiversity indices of alpine meadow steppe on the Qinghai-Tibet Plateau China

Variations of plant biomass and plant species diversity in relation to plateau pika densities in alpine meadow steppe of the Qinghai-Tibet Plateau China were investigated. Peak above- and below-ground biomass, botanical composition, and soil moisture were measured and from these species and functional diversity indices were calculated with reference to pika burrow densities, biomass and soil moisture. Biomass components generally decreased with increased pika burrow density. Biomass of sedges and forbs increased whereas aboveground biomass of grasses first increased and then decreased as burrow density increased. There were positive linear relationships between aboveground biomass and both species and functional group richness and diversity, and also between soil moisture and these indices. These results are relevant to considerations of whether plateau pika is a pest or is a key species in maintaining the ecological stability and biodiversity of its indigenous habitat.