Landscape Analysis Over 30 Years to Assess the Impact of River Damming On Natural Ecosystem

Abstract

Although there are considerable profits in dam projects, they contribute to significant environmental changes. Landscape patterns are influenced by human pressure and are altered continuously. This study investigated the changes in the landscape pattern of Jask's coastal area in Iran due to the Jagin River dam's construction. A proposed methodology employed satellite images from 1987 to 2018 and classified them by multiple approaches to make LULC maps. Eight information categories were evaluated after classification. The accuracy of the classification was determined using the error matrix and kappa index. FRAGSTATS software was applied to calculate several landscape metrics such as edge density (ED), largest patch index (LPI) and Shannon's diversity index (SHDI). The study reported that water right especially in the recent years, because of excessive use of reserve water, decreased and downstream of Jagin River was dried. The landscapes were continuously characterized by anthropogenic pattern features (agriculture land, aquaculture land, built-up land and residential land) after the dam's construction. Rangeland cover and riparian vegetation decreased, and agriculture land increased with in filling pattern. The sand dune area has been spread to the residential area and roots of mangrove forests, because of this reason some parts of mangrove forest dried and roads are covered by sand dune. Their temporal comparison allowed us to localize the change in landscape patterns under the study time. The results can help decision-makers to evaluate the net benefits acquired as a result of the dam projects. Introduction:Land cover generally has a close correlation with human activities and the physical environment. Its interaction with physical, ecological, geomorphic and anthropogenic processes is significant and they can change it drastically. Between all the mentioned factors, anthropogenic is a critical factor that causes some changes in land cover and land-use (Singh et al., 2017). Detection of LULC change of the Earth's surface is extremely important for any kind of sustainable development program and helps to provide a solution for social, economic and environmental problem (El-kawy, Rød, Ismail, & Suliman, 2011) The spatial structure and form of landscape components are considered as Landscape patterns. Land-cover and land-use change (LCLUC) alters landscape patterns and affects regional ecosystems (Zhang, Kung, & Johnson, 2017).Landscape patterns concept have been reflected in several different subjects such as land-use change, urban planning, environmental protection, ecological construction and policy making continuously. Over the past three decades, the study of the spatiotemporal patterns of landscape has been one of the most critical hotspot research subjects (Gustafson, 2019 ; Feng et al., 2018). Landscape ecologists might be unable to detect landscape pattern attributes such as habitat provision or soil degradation if pattern measurement limits to a few points within a land-cover sequence ( Feng et al., 2...