Citation:

Grudzinski, B., K. Fritz, H. Golden, Tamara Newcomer Johnson, J. Rech, J. Levy, J. Fain, J. McCarthy, B. Johnson, T. Vang, AND K. Maurer. A global review of beaver dam impacts: Stream conservation implications across biomes. Global Ecology and Conservation. Elsevier B.V., Amsterdam, Netherlands, 37:e02163, (2022). https://doi.org/10.1016/j.gecco.2022.e02163

Impact/Purpose:

Beaver (Castor spp.) populations have been increasing and re-expanding across their historical ranges over the past few decades. The purpose was to review the impacts of beaver dams on stream systems across different biomes (biogeographical regions formed in response to shared climatic and vegetation conditions) with the following goals: 1. Identify well-studied and understudied biomes by summarizing the spatial distribution of peer-reviewed publications related to stream morphology, hydrology, water quality, aquatic biota, and habitat selection; 2. Summarize the results of these studies for each topic; and 3. Summarize the extent to which beaver impacts on stream environments varied or were consistent among biomes. Our review provides a current understanding to environmental managers on how the conservation, expansion, and reintroduction of beaver can alter streams across different biomes.

Description:

Beaver are recolonizing previously occupied regions, expanding into new territories, and increasingly being introduced and protected for stream conservation and restoration across numerous biomes. However, beaver dam effects on the physical, chemical, and biological characteristics of streams may vary within and among biomes. A comprehensive review of these impacts is lacking. The goals of this review were to: 1) summarize the distribution of studies by biome on beaver dam effects related to channel morphology, hydrology, water quality, and aquatic biota, as well as on beaver habitat selection, 2) summarize the extent to which beaver dam impacts have been consistent within and among biomes, and 3) share testable hypotheses regarding beaver impacts within understudied biomes. We quantify the directionality of beaver dam impacts from 267 peer-reviewed studies. Results show that the majority of studies have been completed within temperate forest environments and that many biomes are understudied. Across biomes, beaver preferred sites for dam development characterized by relatively low gradients and unconfined reaches with small drainage areas. Overall, parameters related to stream morphology and hydrology showed relatively consistent responses to beaver dams within and among biomes, yet water quality and biotic responses were variable among biomes. Responses also varied by parameter within water quality and biotic impact categories. The findings of this study can be useful for stream conservation and restoration efforts that introduce or protect beaver. Additional studies are needed within arid and cold biomes historically occupied by beaver and in novel biomes where beaver populations are currently expanding.

URLs/Downloads:

Record Details: