The study of impact rangeland vegetation changes in relation to the flood occurrence in arid and semi-arid of Iran

Rangeland use is the most important land use in Iran, as more than half of the country is categorized in this land use. Regulating the hydrological cycle and flood control are among the regulatory services in rangeland ecosystems. The flood event in late March 2019, which occurred on vast areas of Iran caused severe damages to natural and human resources. This study was conducted to assess the contributing factors to rangeland degradation in Northern Iran, which tries to assess the relationship between these factors and the flood. Thus, by filed visit of rangelands in the flooded areas of Golestan province, the rangeland condition was determined based on the modified four factor method. Landsat satellite images between 2008-2009 and 2018-2019 were used to determine the area of land use changes. Semi-structured interviews with 69 local pastoralists were also conducted to identify the contributing factors to the floods. Results showed that the rangeland condition in different flooded areas are mainly in the very poor to poor category and grazing intensity on these areas is more than 1.3 times the rangeland grazing capacity. Findings of satellite images analysis revealed that rangeland landuse has had a decreasing trend between 2008-2019 in Atrak and Gorganrud basins where 70,000 ha of landuse change is estimated. Result from the semi-structural interviews introduced over grazing and high prices of supplementary feeding are the main factors affecting the degradation of rangelands in the north of Golestan province from pastoral communities’ point of view. We found that 91% of the participants believed rangeland road networks and 76% believed livestock loss were the most affected items in the 2019 flood. Therefore, it is recommended that rangeland conservation, restoration and development planning should become a priority and necessary measure for flood control and management.