A new study indicates that drone-based hyperspectral imaging can assist in detecting grassland degradation and monitoring plant community changes under various grazing pressures. This method may offer supplementary information for assessing grassland conditions.
Livestock grazing is a significant pressure on global grasslands, with effects ranging from supporting biodiversity under moderate grazing to declines in productivity and shifts in species composition under heavier grazing. Traditional monitoring faces challenges in capturing these changes, which involve vegetation cover, plant functional traits, and species interactions.
New Insights from Remote Sensing
Researchers from Peking University, Beijing Forestry University, Inner Mongolia University, the University of Twente, and Sun Yat-sen University published a study on February 3, 2026, in the Journal of Remote Sensing. The investigation explored the use of drone-based hyperspectral data to monitor ecological changes in China's Xilin Gol Grassland Nature Reserve.
Key Findings on Grazing Impact
The study found that drone observations could accurately estimate aboveground biomass and several plant functional traits. Biomass generally decreased with increased grazing intensity, particularly under heavy grazing.
Nutrient-related traits tended to decline, while traits like leaf thickness and leaf carbon content typically increased, suggesting a shift towards more stress-tolerant plant strategies.
Under heavier grazing, the relationships between plant traits and biomass became stronger. Functional diversity also showed a more positive association with biomass at higher grazing intensity.
Additionally, patterns in trait networks were linked to biomass, with less connected trait relationships corresponding to lower biomass under stronger grazing pressure. These results suggest that insights into grassland responses to grazing can be gained by examining changes in plant traits and community organization.
Expert Perspective
Dr. Yiwei Zhang from Peking University, the study's first author, stated that grassland monitoring could benefit from assessing changes in plant traits and community structure under grazing pressure, beyond just the quantity of vegetation.
Methodology and Broader Implications
The research was based on a long-term grazing experiment initiated in 2013, which included treatments such as grazing exclusion, light grazing, moderate grazing, and heavy grazing. The combination of drone observations and field measurements allowed researchers to connect aerial patterns with ground-level ecological changes.
The study's broader implication is that remote sensing approaches, by capturing changes in plant traits and community organization, can provide additional information on how ecosystems respond to grazing pressure. This could support more comprehensive and timely assessments of grassland condition, particularly in areas where extensive field monitoring is challenging.