Pastures in south and central Tibet (China) II. Probable causes of pasturedegradation

The possible causes of pastureland degradation and the extent to which they may be connected with catastrophes suffered in recent winters are discusse d. Although the causes are complex and varied, changes in the pastoral syst em play a crucial role. The pika problem is discussed in derail, because pi kas are blamed for pasture degradation in many areas and extermination prog rams have been carried out. However, the occurrence of pika in great number s is not the cause, but rather the effect of pastureland degradation. Cutti ng of turf and pear creates the most serious impact on pastureland - not in terms of expansion but finality. In the last chapter the basic rules of HA PIE (High Altitude Pasture Integrative Ecology) are outlined.