Beyond the Dam: the Influence of Beaver on Stream and Riparian Dynamics

Beaver are widely acknowledged as ecosystem engineers because of their impacts on hydrology and vegetation. Surveys on streams in SW Montana show that beaver affect channel processes and riparian plant recruitment well beyond dams, and long after dams have breached. Beaver activity may be best viewed as a cycle, from riparian plant browsing through dam building, failure, and abandonment, with each phase influencing fluvial and riparian processes. Breached dams can initiate meanders and promote habitat diversity while major quantities of willow cuttings from beaver herbivory colonize exposed sediment by sprouting, and promote further sediment accumulation. Radiocarbon dating shows that beaver cuttings remain intact in sediments for thousands of years, adding to floodplain carbon storage