Beaver dam influences on streamflow hydraulic properties and thermal regimes.
Beaver dam influences on streamflow hydraulic properties and thermal regimes.
复制标题
海狸坝对水流水力特性和热状况的影响。
DOI：
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发表时间：
2017
影响因子：
9.8
通讯作者：
B. Roper
中科院分区：
文献类型：
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作者：
M. Majerova;B. Neilson;B. Roper
河狸坝改变了河道水力学，反过来又改变了河流的地貌模板。地貌单位的变异性，河流系统的组成部分，以及水温，河流生态功能的关键，定义栖息地的异质性和可用性。虽然先前的研究表明河狸坝对河流水力学，地貌模板或温度的影响，这些栖息地措施之间的联系或反馈还没有得到很好的理解。这留下了问题，在不同的空间尺度上的温度变化之间的关系，以水力特性，如流的深度和速度，是依赖于地貌。我们结合联合收割机详细预测的水力特性，基于实地的地图与地貌单元的额外分类方案，并详细的水温观测整个研究达到证明这些因素之间的关系在不同的空间尺度（达到，比弗坝坝复合体，地貌单元）。在为期三周的低流量期间，我们发现温度在上游和下游范围之间变化2 °C，白天净变暖1 °C，夜间净冷却0.5 °C。在比弗坝复合尺度上，白天净变暖1.15 °C，夜间变冷。尽管在这些较大尺度上温度变化有限，但由于地貌单元的多样性，比弗坝复合体内的温度变化高达10.5 °C。在地貌单元尺度上，主要地貌单元内的高度变化的流速和深度分布提供了一个解释，在大坝复杂的温度变化和洞察力增加栖息地异质性。
Beaver dams alter channel hydraulics which in turn change the geomorphic templates of streams. Variability in geomorphic units, the building blocks of stream systems, and water temperature, critical to stream ecological function, define habitat heterogeneity and availability. While prior research has shown the impact of beaver dams on stream hydraulics, geomorphic template, or temperature, the connections or feedbacks between these habitat measures are not well understood. This has left questions regarding relationships between temperature variability at different spatial scales to hydraulic properties such as flow depth and velocity that are dependent on the geomorphology. We combine detailed predicted hydraulic properties, field-based maps with an additional classification scheme of geomorphic units, and detailed water temperature observations throughout a study reach to demonstrate the relationship between these factors at different spatial scales (reach, beaver dam complexes, and geomorphic units). Over a three-week, low flow period we found temperature to vary 2 °C between the upstream and downstream extents of the reach with a net warming of 1 °C during the day and a net cooling of 0.5 °C at night. At the beaver dam complex scale, net warming of 1.15 °C occurred during the day with variable cooling at night. Regardless of limited temperature changes at these larger scales, the temperature variability within a beaver dam complex reached up to 10.5 °C due to the diversity of geomorphic units. At the geomorphic unit scale, the highly altered flow velocity and depth distributions within primary geomorphic units provide an explanation of the temperature variability within the dam complex and insight regarding increases in habitat heterogeneity.