Intensified use of agricultural lands have caused biodiversity declines in semi-natural grasslands worldwide. Paddy consolidation is a major driver of a decrease in herb diversity in semi-natural grasslands (hereafter Satokusachi) on paddy levees in Japan. In this study, we examined the effects of paddy consolidation on plant community on Satokusachi. We compared vegetation and environmental variables (vegetation height, soil water content and soil pH) on Satokusachi between traditional and consolidated paddy terraces and examined the relationship between environmental and vegetation changes after consolidation. We found no difference in soil water content between traditional and consolidated levees whereas vegetation height and pH differed between them. Significant perennial species decline and annual and invasive species increase were found on consolidated levees compared to traditional ones. Our results suggest that decrease in vegetation height was one of the major drivers of the vegetation change on consolidated Satokusachi.