Spatial forest disturbance modeling using landscape metrics in Sarvelat protected area of Iran

Document Type : Research Paper

Authors

1 Prof., Faculty of Natural Resources, University of Tehran, Karaj, I.R. Iran.

2 M.Sc. Graduate, Faculty of Natural Resources, University of Tehran, Karaj, I.R. Iran.

Abstract

Spatial disturbance occurs in the forest through the creation of gaps. Updated information in the field of disturbance is essential for the management and protection of the forests. This research was carried out with the aim of providing the status of spatial disturbance of Sarvelat protected area in northern Iran using remote sensing and landscape metrics. The accurate map of the forest/non-forest was prepared by onscreen digitizing method using Landsat 8 data. Based on the metrics graph analysis for ten random points in the zones with different area, the optimal area for gridding was determined. Moreover, the studied area was divided into 252 hexagonal zones with the area of 100 hectares each one. Spatial distribution, connectivity and composition of non-forest patches in each zone were measured using eight spatial metrics (MESH, NP, PD, ENN-MN, AREA-MN, DIVISION, PLAND and SHAPE-MN) in Fragstats software and the map of any metric was prepared. After standardization of metrics values, Principal Component Analysis was done to determine the weight of metrics in the spatial disturbance model. Afterwards, based on the weighted metrics, the map of disturbance index was prepared and classified in four classes of disturbance including very low, low, medium, and high. According to the results, the mentioned classes cover 51, 25, 14 and 10 percentage of the studied area, respectively. It should be mentioned that the high level of disturbance is related to the mountainous areas and rangelands. If these sections are removed from the prepared map, the forest protected area has a relatively good situation. However, due to the beautiful nature and tourism attractions, the area is highly exposed to conversion to road and villa constructions and therefore increasing disturbance.

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