Search

Population growth followed by increasing human needs has caused widespread environmental changes in various ecosystems. Change detection is necessary to properly manage the ecosystem and protect the structure and functions of ecosystems. Landscape ecology provides concepts, theories, and methods for assessing and managing lands. In the current study landscape metrics were used to assess spatio-temporal changes in the Sistan Plain. Landscape metrics were created at class and landscape levels. These indices were calculated, using land use/cover maps of 1977, 2000, 2015, and 2021. Results showed that at the class level, the highest number of patches and fragmentation of the vegetation cover was occured in 2000 and the lowest number of vegetation patches was in 1977. With the inflow of water from Helmand and Farahrood rivers in 2015 and 2021, the vegetation cover, comprising a variety of Tamarix sp, Aeluropus sp, and Phragmites sp, has increased. Due to the inundation of Hamoun and Farah rood rivers, the water and vegetation cover has fewer patches with more connectivity. The highest number of patches in the water body class was in 2015, due to the limited inflow from the Hamoun wetland and the lowest number of water body patches was observed in 1977. This study shows that landscape metrics can determine changes in arid ecosystems. Also, these metrics can quantify the changes in ecosystems and be used in ecosystem management of arid lands. [ABSTRACT FROM AUTHOR]

Understanding effects of environment on the distribution of economic fish is a fundamental step in the ecosystem-based management and ultimately a standard approach in management policies. Bigeye tuna (Thunnus obesus) is one of the most important aquatic species harvested in the Indian Ocean. The present study investigated the association of different variables effecting the rate of catch and distribution of bigeye tune, using generalized additive model (GAM) and maximum entropy (MaxEnt) and satellite derived environmental variables in the Indian Ocean. Results highlighted the importance of temporal and spatial variables along with the eddy kinetic energy, sea level height, depth of 20°C isotherm and sea surface temperature on the distribution of the species. The most suitable habitat predicted by MaxEnt model was observed around the latitudes of 0 to 5 degrees of north and south, mainly in the western part of the Indian Ocean and longitude of 45 to 70 degrees east. Using satellite data, the present study determinied the important factors and suitable habitats for the species, which can be useful for Iranian fisheries managers to increase the fishing efficiency and implementing of ecosystem-based fisheries management in the shared exploited stocks of the Indian Ocean. [ABSTRACT FROM AUTHOR]