Potential anthropogenic and climatic factors affecting Iran’s international wetlands

Human development has reached more than 80% of the earth’s surface and in Iran has had devastating effects on aquatic ecosystems such as wetlands. In addition to human development, climate change is also an important factor that threatens the health of Iran’s wetlands. Very few studies have examined the major threats to Iran’s international wetlands, and it is not clear to what extent these wetlands are affected by anthropogenic and climatic pressures. Therefore, determining how vulnerable these ecosystems are to human development and climate change can help us better manage and restore them. In this regard, this study is aimed at measuring the changes in water bodies of 24 international wetlands when comparing late summer 2000 and 2020 using Landsat images. Next, we calculate the upstream dams’ water bodies and discover the long-term trend of precipitation and temperature changes around the wetlands. Our results show that nine wetlands, most of which were marine and estuarine, increased in area between 2000 and 2020. However, eleven wetlands experienced a 1.0–53.5% decrease in their water area by 2020. Our findings suggest that climate change can be a significant factor affecting some of the wetlands studied. Conversely, certain wetlands have experienced a rising trend in precipitation between 2000 and 2020, making it challenging to link the decline in their water levels to climate change. Nevertheless, for seven of the wetlands, we observe an increase in the water areas of upstream dams between 2000 and 2020 and find no strong evidence for climate change effects. Therefore, the construction of dams upstream may be the primary reason for the drying of these wetlands, and in this case, more of a threat than climate change.