Biogeomorphic influences on river corridor resilience to wildfire disturbances in a mountain stream of the Southern Rockies, USA
Biogeomorphic influences on river corridor resilience to wildfire disturbances in a mountain stream of the Southern Rockies, USA
复制标题
生物地貌对美国落基山脉南部山区河流走廊抵御野火干扰的影响
DOI：
10.1016/j.scitotenv.2022.153321
复制
发表时间：
2022
影响因子：
9.8
通讯作者：
Morrison, Ryan R.
中科院分区：
文献类型：
--
作者：
Wohl, Ellen;Marshall, Anna E.;Scamardo, Julianne;White, Daniel;Morrison, Ryan R.
我们研究了落基山脉南部山区河流走廊的9.4公里长的部分，其中8公里的上部在2020年燃烧。我们专注于沉积物存储在堵塞回水和空间异质性河流走廊衰减下游流量的材料野火。更广泛的部分河流走廊表现出更大的空间异质性，反映在多线程通道平面和更紧密的间隔废弃海狸坝和跨渠道的堵塞。多股流河段的淤塞比单股流河段的淤塞具有更大的滞水容量和更细的泥沙。尽管在野火后的第一个径流季节期间，回水储存中的沉积物大量周转，但在2021年径流季节之后，11个监测的logjams中储存的沉积物累积体积是火灾后立即在logjams中累积沉积物体积的71%。洪泛区植被再生也更快，更完整的多线程达到。植被恢复有助于在这些河段的漫滩沉积，在单线河段观察到的银行侵蚀。更多的空间异质部分的河流走廊似乎是不成比例的重要衰减增强输入的沉积物野火后，这种衰减的累积效应，整个河流网络可能会增强流域规模的恢复力野火干扰。
We examine a 9.4-km-long portion of a montane river corridor in the Southern Rockies, the upper 8 km of which burned in 2020. We focus on sediment storage in logjam backwaters and how spatial heterogeneity in the river corridor attenuates downstream fluxes of material following the wildfire. Wider portions of river corridor exhibit greater spatial heterogeneity, as reflected in multithread channel planform and more closely spaced abandoned beaver dams and channel-spanning logjams. Logjams in multithread reaches have greater volumes of backwater storage and store finer sediment than logjams in single-thread reaches. Despite substantial turnover of sediment in backwater storage during the first runoff season after the wildfire, the cumulative volume of sediment stored at 11 monitored logjams following the 2021 runoff season was 71% of the cumulative sediment volume at the logjams immediately after the fire. Floodplain vegetation regrowth was also faster and more complete at multithread reaches. Vegetation recovery contributed to overbank deposition in these reaches, in contrast to the bank erosion observed in single-thread reaches. More spatially heterogeneous portions of the river corridor appear to be disproportionately important in attenuating enhanced inputs of sediment following wildfire, and the cumulative effect of this attenuation across a river network likely enhances watershed-scale resilience to wildfire disturbance.