Impacts of transport corridors on community properties and leaf functional traits are grassland-type dependent on the Qinghai-Tibet Plateau

[Display omitted] •MAP was the key factor shaping patterns of ecological traits in road areas.•Impacts of distance were opposite in dessert steppes and alpine meadows.•Effects of distance exhibited opposite trends above and below 300 mm MAP.•Links between community properties and leaf traits were grassland-type dependent. It is of great importance to study the effects of transport corridors on ecological traits in highly cold grasslands in the context of climate change and increasing human activities. However, the patterns of ecological traits and the reasons of these patterns in these road areas were not yet well understood. Therefore, we examined three community properties and five leaf functional traits at three distances (0 m, 50 m and 100 m) from the edge of two roads on the Qinghai-Tibet Plateau and explored their relationships. The results showed that mean annual precipitation was the key factor shaping the patterns of ecological traits in the road areas. Roads exerted a positive influence on plant communities in desert steppes, as evidenced by increased vegetation height, vegetation coverage, leaf area, and leaf length. In contrast, roads had a negative effect in alpine meadows, resulting in thicker leaves. The study identified a mean annual precipitation threshold of 300 mm, above and below which the effects of distance on specific leaf area (or leaf thickness) exhibited opposite trends. This finding suggests that plants near roads pursued different strategies compared to those far from roads, with slower investment-return strategies in wet environments and faster investment-return strategies in dry environments. Significant relationships between productivity-related community properties and leaf traits were only observed in alpine steppes of the road areas. This study emphasizes the importance of water condition and grassland type on ecological traits in highly cold road areas.