Fuller Matthew R, Leinenbach Peter, Detenbeck Naomi E, Labiosa Rochelle, Isaak Daniel J
Oak Ridge Institute for Science and Education Postdoc at the Atlantic Coastal Environmental Sciences Division, US Environmental Protection Agency, 27 Tarzwell Drive, Narragansett, Rhode Island 02882, USA.
Region 10, US Environmental Protection Agency, 1200 6th Avenue Seattle, Washington 98101, USA.
Restor Ecol. 2022 Sep 1;30(7):0. doi: 10.1111/rec.13626.
River temperatures are expected to increase this century harming species requiring cold-water habitat unless restoration activities protect or improve habitat availability. Local shading by riparian vegetation can cool water temperatures, but uncertainty exists over the scaling of this local effect to larger spatial extents. We evaluate this issue using a regional spatial stream network temperature model with covariates representing shade effects to predict mean August stream temperatures across 78,195 km of tributaries flowing into the Columbia River in the northwestern US. We evaluate nine scenarios predicting stream temperatures for three riparian shade conditions (current, restored, and no riparian vegetation) within three different climate periods (2000s, 2040s, and 2080s). Results suggest riparian shade restoration (2000s climate) could decrease mean August stream temperatures by 0.62°C across the study network. Under the same restored shade conditions, temperature predictions for tributaries at their confluence with the Columbia River range from 0.02-2.08°C cooler than under current shade conditions. The climate warming effect predicted for the 2040s and 2080s, however, is greater than the cooling effect from restoring riparian shade. Streams less than 10m bankfull width cooled more frequently with riparian shade restoration. In Oregon, the proportion of fish habitat for salmon and trout rearing and migration that meet temperature numeric water quality criteria could be increased by 20% under restored shade conditions although net habitat declines may still occur in the future. We conclude riparian vegetation restoration could partially mitigate future warming and help maintain cold-water habitats that function as thermal refuges if implemented strategically.
预计本世纪河流温度将会升高，这将对需要冷水栖息地的物种造成危害，除非开展恢复活动来保护或改善栖息地的可用性。河岸植被的局部遮荫可以降低水温，但这种局部效应在更大空间范围上的扩展情况尚不确定。我们使用一个区域空间河流网络温度模型，并结合代表遮荫效应的协变量，来预测流入美国西北部哥伦比亚河的78195公里支流在8月份的平均水温。我们评估了九种情景，预测了三种不同气候时期（2000年代、2040年代和2080年代）内三种河岸遮荫条件（现状、恢复后和无河岸植被）下的河流温度。结果表明，在研究网络范围内，河岸遮荫恢复（2000年代气候）可使8月份的平均河流温度降低0.62°C。在相同的恢复遮荫条件下，支流与哥伦比亚河交汇处的温度预测比当前遮荫条件下低0.02 - 2.08°C。然而，预计2040年代和2080年代的气候变暖效应大于河岸遮荫恢复带来的降温效应。河岸遮荫恢复后，河宽小于10米的溪流降温更为频繁。在俄勒冈州，恢复遮荫条件下，符合温度数值水质标准的鲑鱼和鳟鱼养殖及洄游鱼类栖息地比例可增加20%，尽管未来净栖息地仍可能减少。我们得出结论，如果进行战略实施，河岸植被恢复可以部分缓解未来的气候变暖，并有助于维持作为热避难所的冷水栖息地。
