Shulin Liu, Tao Wang, Wenping Kang, Mouat David
Desertification, Baseline, Indicator, Temporal, Spatial scale
Desertification is one of the most serious environmental and socioeconomic problems in the world. Desertification has got ever-increasing attention from scientists to policy makers worldwide. Monitoring and assessing desertification (MAD) has been a key and extreme important work, for combating desertification in threatened areas. Tremendous progress has been made in MAD during the last several decades, including multi-level indicator system, various kinds of extracting and assessing method of desertification information, etc. In particularly, Remote Sensing has become an important data source and technology in MAD due to its strength of macroscopic, synthesis, abundant information, quickly updated data, but it focused primarily on biophysical symptoms and involved some uncertainties challenging MAD. In this paper, several key challenges in MAD were reviewed and discussed. Some findings were given, mainly including: (1) the reference frame or baseline of desertification usually lacking of enough scientific support from environmental background reconstruction and ecosystem dynamics, (2) effective and readily accessible monitoring indicators of desertification usually lacking of reliability and scientific basis derived from bio-physics mechanism of desertification process, (3) underemphasized temporal and spatial scales of desertification and the scale effect, as well as (4) those extracting and assessing methods of real desertification information in need of improvement. Finally, some suggestions were put forward for advancing desertification research and providing authentic desertification information, including more distinct desertification connotation, addressing desertification research at multiple temporal and spatial scales, integrated application of multisource remote sensing data, closely combining MAD with field research work about desertification processes, establishing and protecting natural ecosystems’ reserves with different climate types and vegetation types for desertification baselines, etc.