Abstract：
Understanding the effects of environmental stressors (e.g., potential changes in climate and land use) on ecological status is essential for freshwater management. The ecological response of rivers to stressors can be evaluated by several physico-chemical, biological, and hydromorphological elements as well as computer tools. In this study, an ecohydrological model based on SWAT (Soil and Water Assessment Tool) is used to investigate climate change impact on the ecological status of Albaida Valley Rivers. The predictions of five General Circulation Models (GCMs) each with four Representative Concentration Pathways (RCPs) are employed as input to the model for simulating several chemical and biological quality indicators (nitrate, ammonium, total phosphorus, and the IBMWP (Iberian Biological Monitoring Working Party) index) in three future periods (Near Future: 2025-2049, Mid Future: 2050-2074, and Far Future: 2075-2099). Based on chemical and biological status predicted with the model, the ecological status is determined at 14 representative sites. As a result of increased temperatures and decreased precipitations from most of GCMs projections, the model predicts decreased river discharge, increased concentrations of nutrients, and decreased values of IBMWP for future compared to the baseline period (2005-2017). While most representative sites have poor ecological status (10 sites with poor ecological status and four sites with bad ecological status) in the baseline, our model projects bad ecological status for most representative sites (four sites with poor ecological status and 10 sites with bad ecological status) under most emission scenarios in the future. It should be noted that the bad ecological status is projected for all 14 sites under the most extreme scenario (i.e., RCP8.5) in the Far Future. Despite the different emission scenarios, and all possible changes in water temperature and annual precipitation, our findings emphasize the urgent need for scientifically informed decisions to manage and preserve freshwaters.
摘要：
了解环境压力源的影响(例如，气候和土地利用的潜在变化）对生态状况的影响对于淡水管理至关重要。河流对胁迫源的生态响应可以通过几种物理化学方法来评估，生物，和水形态元素以及计算机工具。在这项研究中,基于SWAT（土壤和水评估工具）的生态水文模型用于研究气候变化对Albaida山谷河流生态状况的影响。五个通用循环模型（GCM）的预测，每个模型具有四个代表性浓度路径（RCP），作为模型的输入，用于模拟几种化学和生物质量指标（硝酸盐，铵，总磷,和IBMWP（伊比利亚生物监测工作组）指数）在三个未来时期（近期：2025-2049，中期：2050-2074和远期：2075-2099）。基于该模型预测的化学和生物状态，生态状况是在14个代表性地点确定的。由于大多数GCM预测的温度升高和降水减少，该模型预测河流流量减少，增加了营养物质的浓度，与基线期(2005-2017年)相比，未来的IBMWP值有所下降。虽然大多数代表性站点在基线中的生态状况较差（10个生态状况较差的站点和4个生态状况较差的站点），我们的模型预测在未来大多数排放情景下，大多数代表性地点(4个生态状况差的地点和10个生态状况差的地点)的生态状况差。应该指出的是，在最极端的情况下，所有14个地点的生态状况都是预测的(即，RCP8.5）在遥远的未来。尽管排放情况不同，以及水温和年降水量的所有可能变化，我们的研究结果强调，迫切需要科学决策来管理和保护淡水。
