The researchers studied plant diversity in grassland communities on the Qinghai-Tibet Plateau affected by frozen soil degradation and highway construction. They surveyed different grassland types and succession stages, counting plant species and measuring environmental factors. They found that while the number of plant species was similar across communities, the evenness and diversity of species varied significantly. This suggests that different grassland communities are impacted differently by environmental changes, highlighting the importance of biodiversity for ecosystem stability in these regions.