Roads can act as barriers, negatively influencing the movement of animals and thereby causingdisruption in some major flows of the landscape. This causes
landscape fragmentation and isolation ofpopulations. However, the habitat loss and habitat fragmentation caused roads are not only that occurredby road land-take but also by road noise. The main aim of this study is to provide a method to quantify thedegree of fragmentation caused by road noise using Infrastructural Fragmentation Index. To determine thedegree of landscape fragmentation, two types of fragmentation is determined: land-take fragmentationbased on the road surface only, and noise effect zone fragmentation based on a buffer of 40 dB. Noisepropagation for the roads with a traffic volume of more than 1,000 vehicles per day was simulated by CRTNmodel. Then, both degrees of fragmentation (land-take and noise effect zone) were calculated in sixfragmentation levels for a case study in Zagros Mountains at West of Iran. The study area has three mainhabitats type as oak Forest, scattered woodland and temperate grassland where are the habitat of endangeredand protected animal such as Brow bear, Persian Leopard, etc. Due to topographic conditions and the trafficvolume in the region, the road effect zone ranges from 50 to 2000 m based on a noise level of 40 dB. Wefound that four-fifths of the total areas of the natural habitat patches at the range of 40 dB of the roadnetwork undergo land-take fragmentation. Our results showed that considering only the effect of road landtake29.7 % (577270 ha) is fragmented in very low and low degrees and only 8.3 % (162020 ha) in moderateto very high degrees. While considering the road noise effect zone only 16.7% (325100 ha) are in lowerdegrees and 36.5% (711440 ha) of habitats are under degree of fragmentationfrom moderate to very high.Hence, our results suggest that by quantifying only road-structural habitat fragmentation some sort ofdownscaling happens. Moreover, the additional area of fragmented habitats shifted to about two or morelevels higher classes of degree of fragmentation.