پديدآورندگان :
Madadi Hossein Department of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111, Iran. , Moradi Hossein Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran , Soffianian Alireza Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran , Salman Mahini Abdolrasoul Department of the Environment, Faculty of Fishery and Environment, Gorgan University of Agriculture and Natural Resources Sciences, Golestan, Gorgan, Iran. , Senn Josef Swiss Federal Research Institute WSL, Switzerland. , Geneletti Davide Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano,
Trento, Italy
چكيده فارسي :
Roads can act as barriers, negatively influencing the movement of animals and thereby causing
disruption in some major flows of the landscape. This causes landscape fragmentation and isolation of
populations. However, the habitat loss and habitat fragmentation caused roads are not only that occurred
by road land-take but also by road noise. The main aim of this study is to provide a method to quantify the
degree of fragmentation caused by road noise using Infrastructural Fragmentation Index. To determine the
degree of landscape fragmentation, two types of fragmentation is determined: land-take fragmentation
based on the road surface only, and “noise effect zone” fragmentation based on a buffer of 40 dB. Noise
propagation for the roads with a traffic volume of more than 1,000 vehicles per day was simulated by CRTN
model. Then, both degrees of fragmentation (land-take and noise effect zone) were calculated in six
fragmentation levels for a case study in Zagros Mountains at West of Iran. The study area has three main
habitats type as oak Forest, scattered woodland and temperate grassland where are the habitat of endangered
and protected animal such as Brow bear, Persian Leopard, etc. Due to topographic conditions and the traffic
volume in the region, the road effect zone ranges from 50 to 2000 m based on a noise level of 40 dB. We
found that four-fifths of the total areas of the natural habitat patches at the range of 40 dB of the road
network undergo land-take fragmentation. Our results showed that considering only the effect of road landtake
29.7 % (577270 ha) is fragmented in very low and low degrees and only 8.3 % (162020 ha) in moderate
to very high degrees. While considering the road noise effect zone only 16.7% (325100 ha) are in lower
degrees and 36.5% (711440 ha) of habitats are under degree of fragmentation from moderate to very high.
Hence, our results suggest that by quantifying only road-structural habitat fragmentation some sort of
downscaling happens. Moreover, the additional area of fragmented habitats shifted to about two or more
levels higher classes of degree of fragmentation.
