Ecological Impact Assessment of Roads Network on Natural Habitats of Central Iran using SPROADI Landscape Index

Roads are linear human-made infrastructures which affect landscape structure and function and play a substantial role in defining landscape pattern. Road networks affect wildlife habitats in two different ways. First, road construction leads to a direct habitat loss. Second, maintenance and use of road cause various effects altering habitat quality, such as increasing access to hunters, poachers and tourists. Development of roads through protected areas and ecological sensitive regions can have catastrophic effects on wildlife and leaves destructive impacts such as habitat fragmentation and isolation. To better understand how roads impact on wildlife populations and their habitats at landscape scale, it is necessary to quantify to which extent and degree they are affected by these infrastructures. Quantitative characterization of landscapes through derivation of landscape indices helps to define landscape composition and configuration.

The main goal of this study was ecological impact assessment of roads network in natural areas of Western part of Isfahan Province, and Chaharmahal-o-Bakhtiary Province, in Iran. The study consists of many important wetlands and protected areas including Tange Sayad wildlife refuge, which is among the most important habitat for Leopard (Panthera pardus) and Wild Goat (Capra aegagrus) classified as Vulnerable on the IUCN Red List, Choghakhor and Gandoman International wetlands are among the most suitable habitats for migratory birds.

In this study, the ecological impacts of roads network on landscape structure have been analyzed using Spatial Road Disturbance Index (SPROADI). This index uses three sub-indices including traffic intensity, vicinity impact and fragmentation grade to calculate the ecological impacts of road networks.

The results of this study revealed that wide range of natural landscape of study area have been negatively affected by roads network. Our results also revealed that more than 10 percent of Tange Sayad wild life refuges and wide range of suitable habitats of Leopard and Wild Goat are affected by roads and presents a concern for the conservation of these vulnerable species. According to the results of this study, mitigation and compensation activities should be considered in the study area.

Keywords: Road Network, Landscape Structure, SPROADI, Habitat Fragmentation.