Expansion of Phragmites australis in response to climate change and human activities in wetland ecosystems, Ismailia, Egypt

Climate change poses a global threat, affecting ecosystems and species across the world. As a dominant species in wetland habitats, Phragmites australis demonstrates significant adaptive capabilities, particularly in response to changes in temperature and salinity, which can influence germination rates and distribution patterns. This study investigates the spatial expansion of P. australis populations within the wetlands of the study area, examining how climate change has influenced their distribution. Using remote sensing (RS) and GIS tools, the study mapped and monitored changes in land use/land cover and the geospatial distribution of P. australis over a 34-year period (1984–2018) through multi-temporal satellite data processing. In addition, field samples of common reed were collected from 150 squares, along with 36 water and soil samples for analysis in December 2020 and January 2021. The results revealed notable changes: areas of salt crust, urbanization, and water bodies increased at rates of +0.0013 km 2 /year, +1.26 km 2 /year, and +0.21 km 2 /year, respectively, while waterlogged and barren areas decreased by −0.73 km 2 /year and −4.25 km 2 /year. Significant evidence of the plant's expansion was found, particularly at sites with increasing salinity. For instance, at the Abu Khalifa site (AKh-C), salinity reached 28.4 g L −1 , and at Ein Ghosien (EGh-A), salinity was 27.4 g L −1 , creating favorable conditions for reed proliferation. Locations like Abu Atwa and Kilo 2 also showed increased reed coverage, likely due to changes in local water management practices and increased salinity. The increase in these areas' salinity, resulting from altered hydrology driven by climate change and anthropogenic influences like the construction of the Suez Canal, has facilitated the expansion of P. australis . In contrast, areas impacted by urbanization and human disturbance, such as Temsah Lake Extension, displayed slower reed growth due to mechanical removal and habitat degradation. These findings underscore the plant's high adaptability to changing environmental conditions and highlight the urgent need for mitigation strategies to address the implications of P. australis expansion and conserve the biodiversity of the Ismailia region.