A new review led by Institute of Applied Ecology of the Chinese Academy of Sciences highlights how drought will impact grassland vegetation and pastoral livelihoods through interconnected ecological and social processes.

The study was co-authored by Luo Wentao and colleagues, and has been published in BioScience.

This review synthesized recent advances into a unified framework linking plant responses, grassland functioning and human land-use systems.
The review is set against a global context of increasing drought severity. Scientific records indicate that between 1961 and 2024, global dryland areas expanded by approximately 10 million square kilometers. Grasslands cover about 23 percent of the Earth’s land surface and are particularly vulnerable to drought. Drought events become more frequent, intense and prolonged, thus understanding how grasslands respond across biological and societal levels has become an scientific priority.

The researchers integrated findings from ecological and social-ecological studies into a multi-level conceptual framework spanning organisms, ecosystems and human systems. This framework organizes drought impacts across time and scale from physiological stress on plants to changes in community composition, ecosystem productivity, livestock-based livelihoods and land management decisions (Figure 1). The researchers outlined two main trait-mediated pathways through which drought reshapes vegetation structure at the plant community level. One is that species turnover and niche reorganization, where drought-tolerant species expand while water-sensitive species decline. Second is that intraspecific plasticity, a process in which individual plants adjust functional traits such as leaf structure, root allocation and reproductive strategy to cope with water stress. The two mechanisms alter both aboveground and belowground functional traits and influence ecosystem processes such as nutrient cycling and productivity.

The review also detailed how grassland productivity responds to drought and recovery. The authors noted that recovery trajectories are not uniform but instead depend on ecological thresholds. Once drought stress exceeds certain limits (tipping point), grasslands may follow different pathways, including full recovery, partial recovery, compensatory growth or system collapse. The researchers further highlighted that prior drought exposure can either enhance resilience through ecological memory, meaning improved future adaptation, or increase vulnerability through cumulative stress effects. They emphasized that below-ground traits, such as bud bank density, remain underexplored despite their importance in post-drought recovery.

Beyond ecological dynamics, the review traced how drought impacts extend into pastoral social systems. Reduced forage availability can lead to livestock weight loss and higher mortality, which in turn causes economic losses for herders and contributes to land degradation. These feedbacks can reinforce cycles of ecological decline and social vulnerability. The authors also noted that institutional arrangements such as pasture privatization and broader economic globalization have reshaped traditional nomadic practices, making adaptation more complex. In some cases, policy responses may unintentionally intensify pressures. For example, drought relief measures that focus narrowly on feed subsidies can encourage herders to retain livestock during dry periods, increasing grazing pressure and potentially worsening ecosystem stress. Figure 2 summarizes these cascading interactions between ecological change and pastoral livelihoods.

Luo et al. propose three priority directions for future research in this review. First, they call for coordinated experimental networks to study sequential droughts across grasslands to distinguish cumulative impacts from adaptive responses. Second, they recommend integrating plant functional trait measurements with remote sensing and ecosystem modeling to build more comprehensive monitoring systems. Third, they highlight the importance of stronger collaboration among ecologists, social scientists, policymakers and herders to design drought adaptation strategies.

Figure 1. Conceptual framework of drought impacts on grassland vegetation across organizational levels and temporal scales (Image by LUO Wentao).

Figure 2. Cascading interactions between ecological change and pastoral livelihoods (Image by LUO Wentao).