Estimating the Cumulative Effects of Different Roads Using Roadless Volume Index - A Case Study in Yunnan Province

摘要

Roads encroaching into undeveloped areas generally degrade ecological and watershed conditions. The road networks bring forth many ecological effects. The span of documented effects ranges from a few meters to many kilometers and different grade road have distinct impact. We used a metric, roadless volume (RV), which is derived from the calculated distance to the nearest road to estimate the effect of different roads on various ecosystems and took Xishuangbanna Autonomous Region as a case. The results showed that roads had a close positive relationship with ecosystem patch number, village and negative relationship with elevation. The calculated RV index clearly reveal road effect on different land uses. The grassland, shrub, forest land have more roadless volume while constructive lands have less. Scenario analysis showed RV decreased with with the road network completeness. This suggests that full road network data should be considered to avoid the underestimate of the comprehensive effects.