Unmanned aerial vehicle methods makes species composition monitoring easier in grasslands

Species composition plays a critical role in environmental conservation, ecosystem functioning and health of grasslands. However, there is no efficient and long-term monitoring method. In this study, we developed a practical method with unmanned aerial vehicles (UAVs), and tested it along a range of grazing intensities in alpine meadow of the Qinghai-Tibetan Plateau. We found that 1) there were significant linear relationships of widely used species composition indices between this and traditional methods (P < 0.01); 2) along increasing grazing density, there were similar tendencies of these indices estimated by the two methods; 3) the new method was more representative than the traditional one though some specific species were difficult to identify. We concluded that this method is suitable for long-term repeated monitoring of grassland species composition, which will be useful for grassland conservation and management.