Department of Earth and Planetary Sciences, University of New Mexico, MSCO3-2040, 1 University of New Mexico, Albuquerque, New Mexico, 87131, USA.
Environmental Sciences Department, University of Montana Western, 710 S. Atlantic St., Dillon, Montana, 59725, USA.
Sci Rep. 2019 May 31;9(1):8124. doi: 10.1038/s41598-019-44381-2.
Given the direct effects of their dams on hydrology, sediment storage, and vegetation, beaver are widely acknowledged as ecosystem engineers. Here we explore the effects of beaver activity on channel processes and riparian plant recruitment beyond those dams and after dam abandonment in southwestern Montana, USA. Willow cuttings from beaver herbivory are commonly deposited along point bars, adding roughness and promoting sediment accumulation. Most cuttings are found <1 km downstream of an active dam. These cuttings often sprout, aiding in willow colonization and bar stabilization. Thirty-four radiocarbon ages show that beaver cuttings have accumulated by similar processes over thousands of years, adding to floodplain carbon storage. Breached dams can initiate meanders, increasing channel and riparian habitat diversity. Beaver activity thus generates a cycle of frequent disturbance, from dam building and riparian plant browsing through dam failure and abandonment, with each phase influencing channel and floodplain evolution and riparian plant recruitment.
鉴于其水坝对水文学、沉积物储存和植被的直接影响，海狸被广泛认为是生态系统工程师。在这里，我们探讨了海狸活动对美国蒙大拿州西南部河道过程和河岸植物繁殖的影响，这些影响超出了水坝的范围，并且在水坝废弃之后。海狸的啃食柳树枝条通常沿着点坝堆积，增加了粗糙度并促进了沉积物的积累。大多数柳树枝条被发现位于活动水坝下游<1 公里处。这些柳树枝条经常发芽，有助于柳树的定殖和稳定点坝。34 个放射性碳年代测定表明，数千年来，通过类似的过程积累了海狸啃食的枝条，增加了洪泛平原的碳储存。决堤的水坝可以引发河曲，增加河道和河岸栖息地的多样性。因此，海狸的活动产生了一个频繁干扰的循环，从水坝建设和河岸植物啃食到水坝失效和废弃，每个阶段都影响着河道和洪泛平原的演化以及河岸植物的繁殖。
