Characterizing the “fragmentation–barrier” effect of road networks on landscape connectivity: A case study in Xishuangbanna, Southwest China

The “fragmentation–barrier” effect of road network expansion on landscape function draws attention throughout the world. Presently, there is a lack of quantitative analysis to integrate different ecological effects of road networks at landscape scale to depict, compare and evaluate landscape changes. In this study, the “Probability of Connectivity (PC)” index was used to evaluate the effects of road networks on landscape connectivity for an area in Xishuangbanna, Southwest China. The results indicate that the fragmentation effect of road networks decreased in PC value by 15.81%, the barrier effect of road networks decreased in PC value by 11.73% and the combination of the two effects decreased PC value by 32.78%. In conclusion, the combined fragmentation and barrier effects of road networks considerably degraded landscape connectivity more than either individual effect. In addition, the fragmentation effect influenced connectivity to a greater degree for ecological processes having low movement abilities. The barrier effect influenced connectivity to a greater degree for medium to high movement abilities. The combined effects influenced connectivity for those ecological processes of low movement ability within the study area.