School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran, 1684613114, Iran.
Department of Water Engineering and Management, Tarbiat Modares University, Tehran, 14115-111, Iran.
Sci Rep. 2023 Apr 3;13(1):5399. doi: 10.1038/s41598-023-32343-8.
Understanding the effects of climate change and anthropogenic activities on the hydrogeomorpholgical parameters in wetlands ecosystems is vital for designing effective environmental protection and control protocols for these natural capitals. This study develops methodological approach to model the streamflow and sediment inputs to wetlands under the combined effects of climate and land use / land cover (LULC) changes using the Soil and Water Assessment Tool (SWAT). The precipitation and temperature data from General Circulation Models (GCMs) for different Shared Socio-economic Pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, and SSP5-8.5) are downscaled and bias-corrected with Euclidean distance method and quantile delta mapping (QDM) for the case of the Anzali wetland watershed (AWW) in Iran. The Land Change Modeler (LCM) is adopted to project the future LULC at the AWW. The results indicate that the precipitation and air temperature across the AWW will decrease and increase, respectively, under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. Streamflow and sediment loads will reduce under the sole influence of SSP2-4.5 and SSP5-8.5 climate scenarios. An increase in sediment load and inflow was observed under the combined effects of climate and LULC changes, this is mainly due to the projected increased deforestation and urbanization across the AWW. The findings suggest that the densely vegetated regions, mainly located in the zones with steep slope, significantly prevents large sediment load and high streamflow input to the AWW. Under the combined effects of the climate and LULC changes, by 2100, the projected total sediment input to the wetland will reach 22.66, 20.83, and 19.93 million tons under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. The results highlight that without any robust environmental interventions, the large sediment inputs will significantly degrade the Anzali wetland ecosystem and partly-fill the wetland basin, resulting in resigning the wetland from the Montreux record list and the Ramsar Convention on Wetlands of International Importance.
了解气候变化和人为活动对湿地生态系统水文学参数的影响，对于设计这些自然资本的有效环境保护和控制方案至关重要。本研究开发了一种方法，使用土壤和水评估工具（SWAT），在气候和土地利用/土地覆盖（LULC）变化的综合影响下，对湿地的径流量和泥沙输入进行建模。使用欧几里得距离方法和分位数差值映射（QDM）对不同共享社会经济路径（SSP）情景（即 SSP1-2.6、SSP2-4.5 和 SSP5-8.5）的通用环流模型（GCM）降水和温度数据进行了降尺度和偏差校正，用于伊朗安扎利湿地流域（AWW）的情况。采用土地变化模型（LCM）对 AWW 的未来土地利用/土地覆盖进行预测。结果表明，在 SSP1-2.6、SSP2-4.5 和 SSP5-8.5 情景下，AWW 地区的降水和空气温度将分别减少和增加。在 SSP2-4.5 和 SSP5-8.5 气候情景的单独影响下，径流量和泥沙负荷将减少。在气候和土地利用/土地覆盖变化的综合影响下，观察到泥沙负荷和流入量增加，这主要是由于预计 AWW 地区的森林砍伐和城市化增加。研究结果表明，茂密的植被区，主要位于坡度陡峭的区域，可显著防止大量泥沙负荷和高径流量输入到 AWW。在气候和土地利用/土地覆盖变化的综合影响下，到 2100 年，预计湿地的总泥沙输入量将分别达到 SSP1-2.6、SSP2-4.5 和 SSP5-8.5 情景下的 2266、2083 和 1993 百万吨。结果表明，如果没有任何强有力的环境干预措施，大量泥沙输入将严重破坏安扎利湿地生态系统，并部分填满湿地盆地，从而导致安扎利湿地从蒙特勒记录名单和《关于特别是作为水禽栖息地的国际重要湿地公约》中除名。
