LAUSR

Abstract Karst rocky outcrops divert water into the surrounding soil patches in a phenomenon known as the “funnel” effect. Soil depth is a key limiting factor in vegetation restoration in karst landscapes, yet few studies have examined the influence of the karst rock funnel effect on soil-limited plant community assemblages and productivity. We established artificial herbaceous communities with seeds from a karst species pool to evaluate how the species composition and productivity of karst herbaceous communities respond to soil depth and the funnel effect. Three months after species establishment, we found that all artificial communities were dominated by two grasses, Miscanthus sinensis and Lolium multiflorum. Plant abundance increased significantly with increasing soil depth, mainly owing to an increase in the individual numbers of the dominant species. The community coverage, photosynthetically active radiation (PAR) canopy capture rate, and shoot, root and total biomass also increased significantly with increasing soil depth. Funnel size and the soil depth × funnel size interaction significantly affected root biomass and root/shoot ratio; however, there was no effect of funnel size or the soil depth × funnel size interaction on species abundance, species richness and diversity, coverage, PAR canopy capture rate, shoot biomass, or total biomass. Therefore, this microcosm experiment provides evidence that the species composition and productivity of karst herbaceous communities are shaped by soil depth. The supply of water via the funnelling effect from karst rocky outcrops did not significantly affect herbaceous community assemblages or productivity, except in terms of root biomass. We suggest that the conservation and development of soil resources in environments with karst rocky outcrops may be more effective for the restoration of karst herbaceous communities than ensuring an adequate water supply.