The effects of visitor activities on surface soil environmental conditions and aboveground herbaceous biomass in Ayder Natural Park, Turkey, were investigated. Soil properties and aboveground herbaceous biomass were identified and characterized as heavily trafficked site (HTS), moderately trafficked sites (MTS) and control (non-trafficked site) in grassland in a forest gap. Some soil properties were measured on 60 pits at 0-5 and 5-10 cm soil depths. The intensity of visitor activities had a negative impact on both surface soil properties and the aboveground herbaceous plant biomass and root mass in the study area in Ayder. The soil bulk density and soil penetration resistance increased from 0.94 to 1.47 g cm(-3) and 0.55 to 1.65 MPa, respectively, saturated hydraulic conductivity decreased from 77.98 to 8.85 min h(-1), and soil organic matter decreased from 6.71 to 1.77% in moderately and heavily trafficked sites, respectively, at 0-5 cm soil depth. The soil properties were degraded at both the surface layer and the subsurface layer and the greatest degradation was measured in the heavily trafficked site followed by the moderately trafficked site. There was a strong negative linear relationship between soil degradation and aboveground herbaceous plant biomass, which decreased by 50.05 and 78.19% in moderately and heavily trafficked sites, respectively.