Comparative Assessment of Landsat‐8 and SPOT‐7 Satellite Data With Field Spectral Measurements for Estimating Plant Diversity in Sandy Grasslands

Remote sensing provides an efficient approach for biodiversity monitoring, yet the relative performance of different data sources in dryland sandy ecosystems is still poorly understood. In this study, we compared Landsat‐8 OLI, SPOT, and hyperspectral data for estimating vascular plant diversity in the Hunshandak Sandland, northern China. Field surveys were conducted in July–August 2016 using 1 m × 1 m plots across four habitat types. Alpha and beta diversity were calculated from field observations, whereas spectral bands, vegetation indices, and texture metrics were extracted from imagery acquired during the growing season. Spearman correlation analysis was used to identify spectral variables associated with plant diversity and compare their performance among sensors. SPOT showed the strongest relationships with alpha diversity, hyperspectral data showed intermediate performance, and Landsat performed relatively poorly. Red‐edge variables and high‐resolution texture metrics were particularly informative. Beta diversity varied among habitats and was mainly driven by species turnover. The weaker performance of Landsat was likely related to mixed‐pixel effects caused by its coarse spatial resolution. These results highlight the importance of spatial resolution and red‐edge information for biodiversity assessment in sandy grasslands.