April 2019 NR/Wildlife/2019-02pr

Beavers: it’s about DAM time!

Eric Thacker, USU Dept. of Wildland Resources, Jamilee Holmstead, USU Dept. of Wildland Resources. In Utah, livestock producers rely on rangelands as the base for their livestock operations. To increase the net income, they receive from grazing livestock; producers desire better information on how livestock and rangelands can be managed to maximize yields. Livestock operations are limited by water availability and mesic areas that produce high-quality forage. In the intermountain west, water and high-quality forage are often limited especially later in the growing season. Thus, during the drier periods of the grazing season, producers often rely on riparian areas to water and feed their livestock (Figure 1). Reliance on riparian areas during these periods may create conflicts with other uses.

A Changing Paradigm In the past rangeland managers often referred to riparian areas as sacrifice areas, because heavy livestock use was considered to be an unavoidable consequence of seasonal grazing (Figure 2). Historic overuse of riparian areas has led to incised stream banks, which lowers the water table. This essentially dries up riparian areas that can lead to less water in the late summer, decreased forage, reduced forage quality, and decreased habitat for many sensitive and endangered species.1 This is in conflict with federal land management, which must ensure proper conditions exist for multiple uses, including conservation of native species. Increased recognition of riparian area values for uses other than livestock grazing has led to land management

changes to ensure protection and ecosystem functions of riparian areas (Figure 3). While these changes have protected existing riparian areas, few land management options exist to expand or increase the extent of riparian areas. Increasing the number and size of riparian areas would increase water and forage availability for livestock and habitat for a wide variety of wildlife. Current research suggests that reintroducing beavers (Castor canadensis) or mimicking beaver activity in riparian areas may help resolve this issue by allowing for livestock owners to achieve their goal while providing habitat for wildlife species dependent on riparian areas (Figure 4).2

A Beaver Dam Solution

Beaver activity in an area slows down water flow and increases ground water recharge. When there are no beavers in an area that needs treatment, we can create artificial dams that mimic natural ones. The effects of natural and artificial dams, and beaver activities, are as follows: Water availability

- Beaver dams increase water retention in the stream by creating pools and ponds.3

- Dams slow stream flows increasing use of existing water sources – how? What uses?3

- Dams raise the water table and flood surrounding areas, recharging water sources, such as nearby ponds and wet meadows (Figure 5.)4

Figure 1. Sheep grazing good condition rangeland.

Figure 2. Degraded Riparian.

Figure 3. Riparian areas are important areas for

wildlife habitat and recreation.

- Dams create natural reservoirs, which extend water availability throughout the year5

Forage Quality and Availability

- By raising the water table and retaining water, plants have access to water and moister soil longer into the growing season4

- Vegetation stays greener longer because of increased soil moisture4

- Dams help create wet meadows through flooding and raised water table4

- Wet meadows increase the quality and quantity of forage especially later in the summer and into the fall.6

Sensitive and Endangered Species Habitat

- Beaver dams create pools, ponds, and slower moving streams. This provides habitat for young fish7

- Create off stream rearing habitat for fish8 - Riparian areas and wet meadows that result

from beaver dams are important for upland game, such as sage-grouse (Centrocercus urophasianus)9

- Beavers cut down trees for food and to make their dams, and often leave downed small trees and branches. These trees, provide shelter and forage for other species such as….10

- Ponds create habitat for sensitive amphibians such as the Columbia spotted frog (Rana luteiventris)11and boreal toad (Anaxyrus boreas).12

Beaver reintroduction or artificial beaver dams provide an essential service to riparian areas that not only help improve natural habitats but benefit all livestock. Beavers provide cheerful restoration that once established, is free and longer lasting than any human efforts. By introducing beavers we allow nature to do its thing, so livestock owners can do theirs.

Figure 4 Beaver (Castor canadensis).

Figure 5. Old beaver dams that have "grassed – in” creating wet meadows.

Work Cited 1. Rosgen, D.L. 1997. A Geomorphaical Approach to

Restoration of Incised Rivers. Accessed 10 January 2018 at http://online.sfsu.edu/jerry/geo_642/refs/A_Geomorphological_Approach_to_Restoration_of_Incised_Rivers.pdf

2. Pollock, M.M., Beechie, T.J., Wheaton, J.M.,

Jordan, C.E., Bouwes, N., Weber, N., and Volk, C. 2014. Using Beaver Dams to Restore Incised Stream Ecosystems. Accessed 10 January 2018 at https://academic.oup.com/bioscience/article/64/4/279/2754168

3. Grunell, A. 1998. The Hydrogeomorphological

Effects of Beaver Dam-Building Activity. Accessed 20 January 2018 at ftp://mcpd.mt.gov/public/Maxell/Beaver/Gurnell,%20A.M.%20%201998.%20%20The%20hydrogeomorphological%20effects%20of%20beaver%20dam-building%20activity.%20%20Progress%20in%20Physical%20Geography.pdf

4. Westbrook, C.J., Cooper, D.J., Baker, B.W. 2006.

Beaver Dams and Overbank Floods Influence Groundwater-Surface Water Interactions of a Rocky Mountain Riparian Area. Accessed 20 January 2018 at http://onlinelibrary.wiley.com/doi/10.1029/2005WR004560/full

5. Leary, R.J. 2012. Landscape and Habitat Attributes

Influencing Beaver Distribution. Accessed 1 February 2018 at https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1350&context=gradreports

6. Westbrook, C.J., Cooper, D.J., Baker, B.W. 2006. Beaver Dams and Overbank Floods Influence Groundwater-Surface Water Interactions of a Rocky Mountain Riparian Area. Accessed 20 January 2018 at

http://onlinelibrary.wiley.com/doi/10.1029/2005WR004560/full

7. DeVries, P., Vitale, A., and Madsen, S. 2012.

Emulating Riverine Landscape Controls of Beaver in Stream Restoration. Accessed 20 January 2018 at http://www.fisheries.go.th/library/app/images/TransactionsoftheAmericanFisheries/fisheriesJune.pdf#page=9

8. Pollock, M.M., Pess, G.R., and Beechie, T.J. 2004.

The Importance of Beaver Ponds to Coho Salmon Production in the Stillaguamish River Basin, Washington, USA. Accessed 10 February 2018 at http://duff.ess.washington.edu/grg/publications/pdfs/Pollock.pdf

9. Fischer, R.A., Reese, K.P., and Connelly, J.W.

1996. Influence of Vegetal Moisture Content and Next Fate on Timing of Female Sage Grouse Migration. Accessed 15 February 2018 at https://www.researchgate.net/publication/257645623_Influence_of_Vegetal_Moisture_Content_and_Nest_Fate_on_Timing_of_Female_Sage_Grouse_Migration

10. Rossell, F., Bozser, O., Collen, P., and Parker, H.

2005. Ecological Impact of Beaver Castor fibre and Castro Canadensis and Their Ability to Modify Ecosystems. Accessed 15 February 2018 at https://brage.bibsys.no/xmlui/bitstream/handle/11250/2438080/Ecological_impact.pdf?sequence=2

11. Devolder, A., and Mellison, C. 2010. US Fish and

Wildlife Services Species Assessment and Listing Priority Assignment Form.

12. Sestrich, C. 2009. Seasonal Movement and Habitat

Use of Boreal Toads (Bufo boreas boreas) Breeding in Hebgen Reservoir, Montana. USDA Forest Service Progress Report to PPL Montana. FS Agreement No: 07-CO-11011107-051

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