Road-induced fragmentation and the environmental value of roadless areas in a partly protected landscape in Central Iran

摘要

This study assessed the effect of road development on vegetation fragmentation in and around a protected area network in western Isfahan Province, Central Iran. As the first study in Iran, an attempt was also made using the weighted linear combination-informed ecological value index of roadless area (EVIRA), to evaluate the environmental value of roadless areas based on a set of ecological and anthropogenic factors. Toward these aims, a Landsat 8-OLI image was processed to delineate land use/cover of the region. Road-induced fragmentation was then estimated by comparing the results of a small set of landscape metrics (DIVISION, SPLIT, MESH, LPI, and NP) measured from the original and road-included LULC map. The results showed road-induced increasing DIVISION (by 4.8-85.9%) and SPLIT (by 0.01-23.1%) and decreasing MESH (by 2.7-14%), LPI (by 1.3-32.4%), and NP (by 6-97.8%) values within all protected areas and across the entire study area, indicating a significant rise in landscape fragmentation and habitat loss. Roadless patch area and Thiessen connectivity stood out as the most salient criteria in determining environmentally valuable roadless areas. The results of EVIRA showed that the study region comprises some valuable but unprotected roadless areas which should be protected against road development or any kind of destructive human activities by laying out conservation plans or their inclusion to the current protected area network.