In this paper, the methods of GIS buffer, spatial comparison, and scenario analysis were
used to elucidate the influence of roads on landscape within Lancang River Valley. The
results showed that forest and shrub land decreased while farmland and constructed land
increased in the past 20 years in the study area. Also, the ecosystem’s change rate near roads
increased while the diversity evenness, patch density and human disturbance indices all
decreased. Different aspects of road development had different negative consequences for
the environment. In Lancang River Valley, forests were most affected by road network development,
although there were also negative affects for grassland, farmland or shrub land and
these differences varied by type of road. The greatest effects for forests were observed near
high-level roads, while the greatest effects for farmland occurred near the low-level roads,
Scenario analysis showed that the fractal dimension index, patch numbers, and average
patch area of ecosystems decreased with development of road network density. The ecological
risk analysis showed that various type roads cause different risk levels and that road
density has a positive relationship with regional ecological risk level at county scale. Also,
different ecological risk level exists in different level roads. Full road network data (density,
level) should be considered to avoid the underestimate of the ecological effects.