Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA.
Center for Limnology, University of Wisconsin-Madison, 680 North Park Street, Madison, WI, 53706, USA.
Environ Manage. 2019 Mar;63(3):396-407. doi: 10.1007/s00267-018-01134-7. Epub 2019 Jan 15.
Cisco (Coregonus artedi) are an important indicator species for cold-water lake habitats in the Great Lakes region, and many populations have been extirpated at their southern range limit over the last century. Understanding the roles of climate and water quality in these extirpations should inform protection of cold-water fishes. Using the water temperature at the depth where dissolved oxygen falls to 3 mg L (TDO3) as a metric, we investigated the roles of climate and water quality as drivers of habitat availability for cisco in Lake Mendota, WI, USA from 1976 to 2013. We find that summer (Jun-Aug) air temperatures, spring (Mar-May) phosphorus load, and spring inflow influence summer TDO3. Warm air temperatures lead to the greatest increases in TDO3, whereas reduced phosphorus loads can reduce TDO3, thus alleviating oxythermal stress. Under air temperatures expected under the A1B climate change scenario, a 25% reduction in phosphorus load would stabilize TDO3 at current levels, while a 75% reduction in phosphorus loading would be required to expand oxythermal habitat. Costs of these reductions are estimated to range from US$16.9 million (-25%) to US$155-167 million (-75%) over a 20-year period but may be feasible by expanding upon current watershed phosphorus reduction initiatives if sustained funding were available. Identifying targeted reductions will become increasingly important throughout the region as warmer temperatures and longer stratification reduces cool- and cold-water fish habitat in many Midwestern lakes under the expected future climate.
白鲑（Coregonus artedi）是大湖区冷水湖泊栖息地的重要指示物种，在上个世纪，许多种群在其南部分布范围的极限处已灭绝。了解气候和水质在这些灭绝事件中的作用，应该为保护冷水鱼类提供信息。我们使用溶解氧降至 3 毫克/升（TDO3）的水深处的水温作为指标，研究了气候和水质作为明尼苏达州门多塔湖白鲑栖息地可利用性驱动因素的作用，研究时间为 1976 年至 2013 年。我们发现，夏季（6 月至 8 月）空气温度、春季（3 月至 5 月）磷负荷和春季入流影响夏季 TDO3。温暖的空气温度会导致 TDO3 最大幅度增加，而减少磷负荷则可以降低 TDO3，从而减轻氧热压力。在 A1B 气候变化情景下预期的空气温度下，磷负荷减少 25%将使 TDO3 稳定在当前水平，而减少 75%的磷负荷将需要扩大氧热栖息地。在 20 年的时间内，这些减少措施的成本估计在 1690 万美元（减少 25%）至 1.55 亿至 1.67 亿美元（减少 75%）之间，但如果有持续的资金支持，通过扩大当前流域磷减排计划，这些措施可能是可行的。随着未来气候变暖，分层时间延长，中西部许多湖泊的冷水和冷水鱼类栖息地减少，在整个地区，有针对性地减少磷负荷将变得越来越重要。
