Abstract:

The plateau pika is a unique small mammal and a key species among the fauna of the alpine rangeland ecosystem on the Qinghai Tibetan Plateau. Therefore， there is a need to monitor and evaluate the level of damage to alpine rangeland caused by the plateau pika. In this study， unmanned aerial vehicle （UAV） technology validated by field observation was used to monitor and evaluate the level of plateau pika damage to rangeland in Maqu county of Gansu Province. Several variables， including the number of pika holes， aboveground biomass， vegetation cover， and proportion of edible forage in the aboveground biomass， among others， were extracted from UAV images by self-designed software. Then a multi-factor index system， comprising the number of pika holes， aboveground biomass， vegetation cover and proportion of edible forage was developed to categorize the degree of damage by plateau pika. Finally， a low altitude remote sensing monitoring methodology suitable for collecting data on plateau pika damage was devised. The system is ready for implementation as a technical tool for efficient and accurate monitoring of plateau pika damage. The main results were： 1） The accuracy of photo interpretation for the pika hole number and vegetation cover was 95% and 93%， respectively， based on field verification. 2） The visible-band difference vegetation index （VDVI） was selected as the best vegetation index for estimating aboveground biomass； for the estimation model constructed， the accuracy was 86.54%. 3） A damage scale was formulated to classify plateau pika damage in the study area （damage to rangeland index， DRI） into five levels as follows： Level I， no damage； Level Ⅱ， light damage； Level Ⅲ， moderate damage； Level Ⅳ， severe damage and Level V， extreme damage.

Key words: plateau pika, UAV remote sensing, damage level