The Plateau Pika (Ochotona Curzoniae):A Keystone Species for Biodiversity on the Tibetan Plateau

【摘要】：正 China was one of the first countries to ratify the Convention on Biological Diversity,and has adopted an aggressive agenda to identify and preserve biodiversity within China.Although the Qinghai-Xizang(Tibetan) Plateau is not as biologically rich as some other areas inChina,it does contain a distinctive and important flora and fauna.Appropriately,much attentionhas been drawn to the massive loss of ungulate species that once flourished on the Plateau.Mostof the ungulate species on the Plateau are listed as Category I or Category Ⅱ Nationally ProtectedFauna in China.However,many other components of biodiversity on the Tibeta Plateau are atrisk,and many of these are directly connected to the biology of the Plateau Pika(Ochotonacurzoniae).This report concentrates on the important role of the Plateau Pika as a KeystoneSpecies for preservation of biodiversity,and argues that widespread poisoning of the pikas isdetrimental to the normal functioning of the Tibetan Plateau ecosystem.A Keystone Species is onethat,if lost,will lead to a cascading effect of reduced biodiversity and interfere with the properfunctining of an ecosystem.The Plateau Pika is a Keystone Species because it l) makes burrowsthat are the primarp homes to a wide variety of small birds(snowfinches,ground jays)and lizards;2)creates microhabitat disturbance that results in an increase in plant species diversity;3)servesas the main prey for most of the small to medium to large predators on the Plateau(weasels,Pallas’cat,red fox,wolves,brown bears,and neary all raptorial birds such as black kites,uplandbuzzards,goshawks,little owls,etc.);and 4)contributes positively to ecosystem-level dynamics.Plateau Pikas are poisoned because their populations may reach high densities-reducing foragefor domestic livestock(yak,sheep,horses),and because they putatively are responsible for habitatdegradation.Research has shown,however,that pikas reach high densities in areas that have beenovergrazed.High density of pikas is,therefore,likely to be a symptom of poor range managementrather than the cause of rangeland degradation.Control measures are also not cost effective.It isalso possible that climate change has contributed significantly to the formation of black sandareas.In summary,it is necessary to look at the big picture when managing biological resourceson the Tibetan Plateau.The Plateau Pika plays a significant roe in the maintenance of theecosystem,and it should be managed only in concert with other uses of the land to ensuresustainability of China’s native biodiversity as well as the long-term usage of the pastureland bydomestic livestock.