Stream ecosystems can be dramatically altered by dam‐building activities of North American beaver (Castor canadensis). The extent to which beavers’ ecosystem engineering alters riverscapes is driven by the density, longevity, and size (i.e. height and length) of the dams constructed. In comparison to the relative ubiquity of beaver dams on the landscape, there is a scarcity of data describing dam heights. We collected data describing dam height and dam condition (i.e. damaged or intact) of 500 beaver dams via rapid field survey, differentiating between primary and secondary dams and associating each dam with a beaver dam complex. With these data, we examined the influence of beaver dam type (primary/secondary), drainage area, streamflow, stream power, valley bottom width, and HUC12 watershed on beaver dam height with linear regression and the probability that a beaver dam was damaged with logistic regression. On average, primary dams were 0.46 m taller than secondary dams; 15% of observed dams were primary and 85% secondary. Dam type accounted for 21% of dam height variation (p <0.0001). Slope (p = 0.0107), discharge (p = 0.0029), and drainage area (p = 0.0399) also affected dam height, but each accounted for less than 3% of dam height variation. The average number of dams in a dam complex was 6.1 (SD ± 4.5) and ranged from 1 to 21. The watershed a beaver dam was located in accounted for the most variability (17.8%) in the probability that a beaver dam was damaged, which was greater than the variability explained by any multiple logistic regression model. These results indicate that temporally dynamic variables are important influencers of dam longevity and that beaver dam ecology is a primary factor influencing beaver dam height. © 2020 John Wiley & Sons, Ltd.

中文翻译：

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地形，地貌和水文变量对美国西部山间河狸坝高度和持续性的影响

北美海狸（加拿大蓖麻）的筑坝活动可以极大地改变河流生态系统。）。海狸的生态系统工程改变河流景观的程度受所建造水坝的密度，寿命和大小（即高度和长度）的影响。与河狸大坝在景观上的相对普遍性相比，缺乏描述大坝高度的数据。我们通过快速的现场调查收集了描述500座海狸水坝的坝高和水坝状况（即受损或完好）的数据，区分了一级和二级水坝，并将每个水坝与一个海狸水坝综合体相关联。利用这些数据，我们通过线性回归检验了海狸坝类型（主要/次要），排水面积，水流，水流功率，河谷底部宽度和HUC12分水岭对海狸坝高度的影响以及海狸坝被破坏的概率。逻辑回归。平均而言，一级水坝为0。比二级水坝高46 m；观察到的水坝中有15％是主要水坝，而次要是85％。大坝类型占大坝高度变化的21％（p  <0.0001）。坡度（p  = 0.0107），排水量（p  = 0.0029）和排水面积（p  = 0.0399）也影响大坝高度，但每种情况都占大坝高度变化的3％以下。水坝综合体中的平均水坝数量为6.1（SD±4.5），范围从1到21。在海狸水坝的分水岭中，海狸水坝遭到破坏的可能性最大（17.8％），大于任何多对数回归模型所解释的变异性。这些结果表明，时间动态变量是影响大坝寿命的重要因素，而河狸大坝的生态学是影响河狸大坝高度的主要因素。分级为4 +©2020 John Wiley＆Sons，Ltd.