Abstract: Studying the variation pattern and its influencing factors of plant species richness in road area can provide references for the management of nature protected areas. Based on literature, we selected five influencing factors that have been most frequently studied, including road width, species attributes, vegetation types, plant growth forms, and latitude to which the road belongs. Their effects on plant species richness in road area were investigated by Meta-analysis. The results showed that, among those five factors, species attributes (native species or not) had the greatest effects on the variation range of plant species richness in road area. The species richness of alien species, native species and unclassified species (alien and native species were not classified) all increased significantly (ranges were 130.5%, 14.9%, and 27.0%, respectively), with the increment of alien plants significantly exceeding that of native plants. The variation range of plant species richness in road area did not show a regular trend as road width increased. The variation range of plant species richness in road area was significantly different above and below 4.5 m road width. Plant species richness in road area did not change significantly within 4.5 m road width, while that of roads between 4.5 m and 26 m increased significantly (the range was 42.1%). The variation range of plant species richness in road area did not change in grasslands, but increased significantly in forests. In coniferous forests, deciduous broad-leaved forests, and evergreen broad-leaved forests, the elevation range of plant species richness in road area decreased (76.7%, 38.0% and 20.3%, respectively). In coniferous forests, the variation range of plant species richness in road area was significantly different above and below 2.75 m road width. Plant species richness in road area within 2.75 m road width was significantly smaller than that for roads between 2.75 and 26 m (18.8%, 74.0%, respectively). In forest road area, the species richness of herb and shrub increased significantly (ranges were 16.2% and 37.6%, respectively), while that of tree species did not change. The latitude of roads did not affect the variation range of plant species richness in road area.

Key words: road, width, road area, plant species richness, influencing factor.