Soil resource heterogeneity promotes species richness only at a fine scale at the early restoration of karst abandoned farmland

The relationship between heterogeneity and plant diversity remains unclear in low-resource karst. We made in situ observations at different spatial scales within a fixed plot on abandoned farmland that had been enclosed for 4 years. Species richness was spatially scale dependent, while species evenness remained consistently low across all scales. Species diversity was positively related to resource heterogeneity only at a fine scale (1 m × 1 m), mainly driven by an increase in the species richness of non-dominant groups. Resource heterogeneity reduced overall plant growth at a large scale. However, it reduced the growth of the dominant families (Asteraceae and Poaceae) at a fine scale, but promoted it at a large scale. Our results suggest that soil resource heterogeneity exerts a scale-dependent positive impact on species richness during the early restoration of abandoned farmland by low resource availability and highlight the importance of fine-scale ecological information in karst areas.