气候变化,对河流沉积物的深远影响,水文,和温度动力学,会加剧对许多物种栖息地条件的影响,特别是那些依赖低潮区的脆弱早期生命阶段的人,比如砾石产卵的鱼类。由于多种压力源效应的复杂性和交互性,我们采用了大型户外中观来系统地测试三种砾石产卵鱼类棕色鳟鱼(Salmotrutta)的繁殖成功,Nase,(Chrondrostomanasus)和多瑙河鲑鱼(Huchohucho)受到变暖(3-4°C)的单独和综合影响,细沉积物(增加<0.85mm22%)和低流量(减少8倍流量)。在所有三个物种中,细沉积物对出苗率和鱼苗长度的影响最大,将褐鳟鱼的出苗率降低到零,9%的Nase,和4%的多瑙河鲑鱼。细沉积物引起的出苗死亡率明显超过孵化,这表明,由于缺氧引起的负面影响被埋葬大大加剧。作为一个单一的压力源,变暖只有轻微的影响,但是低流量使春季产卵物种Nase和多瑙河鲑鱼的出苗率降低了8%和50%,分别。在包括细沉积物在内的联合处理中,然而,所有三个物种的出现成功都产生了强烈的负面反应,即使在塞浦路斯物种Nase中,这表明压力源之间对孵化成功的交互影响很小。变暖和细小的沉积物也导致了鱼苗的早期出现,暗示与可用食物资源异步的风险。这项研究戏剧性地表明,气候变化可能对砾石产卵鱼类的繁殖成功产生有害影响,不考虑分类学或生态学特征。
Climate change, with its profound effects on stream sediment, hydrological, and temperature dynamics, will exacerbate impacts on habitat conditions for many species, particularly those with vulnerable early life stages relying on the hyporheic zone, such as gravel-spawning fishes. Due to the complex and interactive nature of multiple stressor effects, we employed large-scale outdoor mesocosms to systemically test how the reproductive success of three gravel-spawning fish species brown trout (Salmo trutta), nase, (Chrondrostoma nasus) and Danube salmon (Hucho hucho) was affected by individual and combined effects of warming (+3-4 °C), fine sediment (increase in <0.85 mm by 22 %) and low-flow (eightfold discharge-reduction). Fine sediment had the most detrimental effect on emergence rate and fry length in all three species, reducing the emergence rate to zero in brown trout, 9 % in nase, and 4 % in Danube salmon. The emergence mortality caused by fine sediment surpassed that of hatching distinctly, suggesting that negative effects due to hypoxia were considerably exacerbated by entombment. Warming had only minor effects as a single stressor, but low flow reduced emergence rates of the spring spawning species nase and Danube salmon by 8 and 50 %, respectively. In combined treatments including fine sediment, however, the emergence success of all three species responded strongly negatively, even in the cyprinid species nase, which showed little interactive effects between stressors regarding hatching success. Warming and fine sediment also led to the earlier emergence of fry, implying a risk of asynchrony with available food resources. This study dramatically shows that climate change can have deleterious impacts on the reproductive success of gravel-spawning fish species, irrespective of taxonomic or ecological traits.