The importance of plateau pika (Lagomorpha: Ochotona curzoniae) disturbance in ecosystem functioning on the Tibetan plateau: Evidence from alpine meadow vegetation and soil

Background/Question/Methods The plateau pika (Ochotona curzoniae) is a small mammal endemic to the Tibetan Plateau, where its highly-social colonies build extensive underground burrow systems.  In spite of evidence pointing to their role as a keystone species and ecosystem engineer, plateau pikas are intensively poisoned throughout their range.  The underlying assumption of this strategy is that eliminating pikas will improve range quality for domestic yak and sheep.  However, maintaining pikas as an integral part of the alpine meadow ecosystem could provide ecological benefits.  Pika burrowing and foraging may positively impact ecosystem health by stimulating plant growth, increasing species diversity, enhancing soil mixing, and providing habitat for rare fauna and flora.  This study examines several ecological impacts of pikas and their burrows on plant communities and soils in eastern Qinghai Province, China.

Results/Conclusions Pika disturbance was found to increase plant species diversity at the landscape level, as well as significantly alter floral community composition.  Soil nutrient levels were not significantly different at the scales measured.  However, the physical mixing of soil may make differences over small spatial scales difficult to detect.  On the other hand, water infiltration rates varied significantly between pika colony and off-colony areas.  Thus, variation in water availability may be one variable that leads to differences in plant composition near pika burrows.  These findings highlight the need for a more comprehensive analysis of pika impacts on rangeland resources before resorting to pest control measures.