Beavers: The Original Army Corps of Engineers

Beavers: The Original Army Corps of Engineers: Click for larger picture, Beaver with branch in water, Courtesy US FWS
Beaver with branch in water
Courtesy US FWS,
Steve Hillebrand, Photographer


Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

Beavers and beaver dams are a common feature of the Utah landscape. You’ll see the dams on smaller streams and side channels, constructed of branches, downed trees and mud. The still, deep water of the resulting pond creates ideal conditions for a beaver lodge. Beavers can escape and hide from predators by slipping into the pond and disappearing into the lodge. Beavers also use their ponds to cache their favorite
food—aspen and willow.

Because of their tree cutting and dam making skills, humans tend to have two divergent opinions of beavers: 60-pound nuisance or environmental engineer.

Click for larger picture, Beaver Lodge, Courtesy US FWS
Beaver lodge
Courtesy US FWS
Hans Stuart, Photographer

Beavers are considered a nuisance when they gnaw down trees that humans want to keep. Dams can flood roads or stop up irrigation canals. When beaver activity conflicts with human interests, they—the beavers–are likely to be trapped and killed.

However, beaver activity has many positive environmental consequences that we are just beginning to appreciate. Wetlands created by beaver dams help soak up sediments, improving downstream water quality. Because of beaver dams, the winter snowpack isn’t lost in a short spring pulse, This results in a more constant stream flow through the summer –and that’s important as Utah’s climate is predicted to become drier. Finally, beaver dams enhance habitat for many other fish and wildlife species and plants.

Click for larger picture, Beaver in pond, Courtesy US FWS
Beaver in pond
Courtesy US FWS
Steve Hillebrand, Photographer

According to Dr. Joe Wheaton, a geomorphologist at Utah State University, there’s a lot of untapped potential for employing beaver engineers in stream and floodplain restoration. Say you want to restore a stream by reconnecting it with its floodplain. You need to excavate channels, redirect stream flow, revegetate and nurture the
area for a long period of time. To accomplish this, you often need a
number of highly trained professionals and some large Tonka toys.

Alternatively –under the right conditions– you might transplant a
colony of beavers and let them apply their vigorous work ethic to your
landscape and get quite satisfying results.

Recognizing that nuisance beavers can be rehabilitated into hard
working wetland engineers and stream habitat restorationists, the Utah
Division of Wildlife Resources has rolled out the state’s first beaver
management plan in 2010. This plan encourages live trapping of entire
families of beavers in nuisance areas and moves them to specific sites where their
environmental services can be appreciated and put to use.

Click for larger picture, Beaver in snow, Courtesy US FWS
Beaver in snow
Courtesy US FWS

Thanks to the USU College of Natural Resources for supporting this Wild about Utah topic.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

Credits:
Images:
Text: Stokes Nature Center: Holly Strand

Sources & Additional Reading


ARKive Images of Life on Earth, Information Sheet on Castor Canadensis (including some outstanding videos) http://www.arkive.org/ – (BBC Natural History Unit)

  • American Beaver – Overview
  • American Beaver in the Lodge with Young
  • American beaver felling trees and storing food for the winter
  • American beaver scaring moose away from its lodge
  • American beaver returning to its lodge with food

  • Collen, P. and R.J. Gibson. 2001. The general ecology of beavers (Castor spp.), as related to their influence on stream ecosystems and riparian habitats, and the subsequent effects on fish – a review. Reviews in Fish Biology and Fisheries 10: 439–461, 2001. https://www.researchgate.net/publication/227028536_The_general_ecology_of_beavers_Castor_spp_as_related_to_their_influence_on_stream_ecosystems_and_riparian_habitats_and_the_subsequent_effects_on_fish_-_A_review [ Accessed May 1, 2010]

    Prettyman, B. 2009. Utah wildlife: Leave it to the beavers. Article in Salt Lake Tribune, October 16, 2009. http://www.sltrib.com/ci_13570110 [ Accessed April 29, 2010]

    Smithsonian Castor Canadensis Information Page http://www.mnh.si.edu/mna/image_info.cfm?species_id=32 [ Accessed April 29, 2010]

    Big Bend Habitat Restoration Project: A Natural Work of Heart, Open Spaces-A Talk on the Wild Side, US FWS, http://www.fws.gov/news/blog/index.cfm/2016/3/25/Big-Bend-Habitat-Restoration-Project-A-Natural-Work-of-Heart [Accessed March 31, 2016]

    Beaver Dams Strengthened by Humans Help Fish Rebound
    60-Second Science – July 25, 2016 – By Jason G. Goldman02:29 http://www.scientificamerican.com/podcast/episode/beaver-dams-strengthened-by-humans-help-fish-rebound/ Also available through the podcast https://itunes.apple.com/us/podcast/60-second-science/id189330872?mt=2

    Huddling for Warmth

    Beaver in snow, Courtesy US FWS
    Beaver in snow
    Image Courtesy US FWS

    When temperatures dip below freezing and wind hurries on its way, we often find ourselves looking for another warm body to huddle near and share heat. Children snuggle into laps and dogs lean close.

    Many animals huddle to stave off the cold. Species that are strong individualists in balmy seasons seek warmth from a group when temperatures drop. Many non-colonial rodents will share a den come winter.

    [Kevin Colver recording: Songbirds of the Southwest Canyon Country]

    Pygmy nuthatches jam themselves tightly together into tree cavities as do flying squirrels. Through the winter, worker honeybees huddle tightly around a central patch of wax comb where developing larvae are growing. The larvae die if temperatures drop below 83 degrees, so a living blanket of worker bees shivers to generate the heat equivalent to a 40 watt incandescent bulb.

    An animal loses heat in direct proportion to its surface area. By huddling together, each animal reduces its exposed surface area. This in turn allows them to reduce their metabolic rate and so conserve energy at a time when food can be scarce or inaccessible.

    Nests or dens occupied by numerous individuals can be much warmer than ambient. A snow covered lodge with at least 2 beaver occupants can be as much as 35 degrees warmer than the outside air temperature. A study of taiga voles showed that underground nests containing 5 to 10 residents remained 7 to 12 degrees warmer than the surrounding soil and up to 25 degrees warmer than the air above. Individuals take turns going out to forage so their nest remains toasty.

    Living in close proximity does have its problems. Disease and parasites are readily transmitted in tight quarters. Local food competition could potentially lead to hunger or starvation. Predators may more easily discover prey in groups. But for many animals, the advantages of huddling for warmth far outweigh the risks during our chilly winter months.

    This is Linda Kervin for Bridgerland Audubon Society.
    Credits:

    Photos: Courtesy US FWS

    Audio: Courtesy Kevin Colver, https://wildstore.wildsanctuary.com/collections/special-collections, https://wildstore.wildsanctuary.com/collections/special-collections

    Text: Linda Kervin, Bridgerland Audubon Society
    Additional Reading:

    Life in the Cold: An Introduction to Winter Ecology. Peter Marchand. 1991, University Press of New England. http://www.amazon.com/Life-Cold-Introduction-Winter-Ecology/dp/0874517850

    Lives of North American Birds. Kenn Kaufman. 1996, Houghton Mifflin Company. http://www.amazon.com/American-Peterson-Natural-History-Companions/dp/0395770173

    The Birder’s Handbook. Paul R. Ehrlich, David S. Dobkin and Darryl Wheye. 1988, Simon & Schuster, Inc. http://www.amazon.com/Birders-Handbook-American-including-Regularly/dp/1435277589

    Beavers: The Original Army Corps of Engineers

    Beaver with branch in water
    Courtesy US FWS,
    Steve Hillebrand, Photographer


    Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

    Beavers and beaver dams are a common feature of the Utah landscape. You’ll see the dams on smaller streams and side channels, constructed of branches, downed trees and mud. The still, deep water of the resulting pond creates ideal conditions for a beaver lodge. Beavers can escape and hide from predators by slipping into the pond and disappearing into the lodge. Beavers also use their ponds to cache their favorite
    food—aspen and willow.

    Because of their tree cutting and dam making skills, humans tend to have two divergent opinions of beavers: 60-pound nuisance or environmental engineer.

    Beaver lodge
    Courtesy US FWS
    Hans Stuart, Photographer

    Beavers are considered a nuisance when they gnaw down trees that humans want to keep. Dams can flood roads or stop up irrigation canals. When beaver activity conflicts with human interests, they—the beavers–are likely to be trapped and killed.

    However, beaver activity has many positive environmental consequences that we are just beginning to appreciate. Wetlands created by beaver dams help soak up sediments, improving downstream water quality. Because of beaver dams, the winter snowpack isn’t lost in a short spring pulse, This results in a more constant stream flow through the summer –and that’s important as Utah’s climate is predicted to become drier. Finally, beaver dams enhance habitat for many other fish and wildlife species and plants.

    Beaver in pond
    Courtesy US FWS
    Steve Hillebrand, Photographer

    According to Dr. Joe Wheaton, a geomorphologist at Utah State University, there’s a lot of untapped potential for employing beaver engineers in stream and floodplain restoration. Say you want to restore a stream by reconnecting it with its floodplain. You need to excavate channels, redirect stream flow, revegetate and nurture the
    area for a long period of time. To accomplish this, you often need a
    number of highly trained professionals and some large Tonka toys.

    Alternatively –under the right conditions– you might transplant a
    colony of beavers and let them apply their vigorous work ethic to your
    landscape and get quite satisfying results.

    Recognizing that nuisance beavers can be rehabilitated into hard
    working wetland engineers and stream habitat restorationists, the Utah
    Division of Wildlife Resources has rolled out the state’s first beaver
    management plan in 2010. This plan encourages live trapping of entire
    families of beavers in nuisance areas and moves them to specific sites where their
    environmental services can be appreciated and put to use.

    Beaver in snow
    Courtesy US FWS

    Thanks to the USU College of Natural Resources for supporting this Wild about Utah topic.

    For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

    Credits:
    Images: Courtesy US FWS, Photographers: Steve Hillebrand and Hans Stuart, https://images.fws.gov
    Text: Holly Strand, Stokes Nature Center

    Sources & Additional Reading

    Collen, P. and R.J. Gibson. 2001. The general ecology of beavers (Castor spp.), as related to their influence on stream ecosystems and riparian habitats, and the subsequent effects on fish – a review. Reviews in Fish Biology and Fisheries 10: 439–461, 2001. https://www.researchgate.net/publication/227028536_The_general_ecology_of_beavers_Castor_spp_as_related_to_their_influence_on_stream_ecosystems_and_riparian_habitats_and_the_subsequent_effects_on_fish_-_A_review [ Accessed May 1, 2010]

    Prettyman, B. 2009. Utah wildlife: Leave it to the beavers. Article in Salt Lake Tribune, October 16, 2009. http://www.sltrib.com/ci_13570110 [ Accessed April 29, 2010]

    Smithsonian Castor Canadensis Information Page http://www.mnh.si.edu/mna/image_info.cfm?species_id=32 [ Accessed April 29, 2010]

    Big Bend Habitat Restoration Project: A Natural Work of Heart, Open Spaces-A Talk on the Wild Side, US FWS, http://www.fws.gov/news/blog/index.cfm/2016/3/25/Big-Bend-Habitat-Restoration-Project-A-Natural-Work-of-Heart [Accessed March 31, 2016]

    Beaver Dams Strengthened by Humans Help Fish Rebound
    60-Second Science – July 25, 2016 – By Jason G. Goldman02:29 http://www.scientificamerican.com/podcast/episode/beaver-dams-strengthened-by-humans-help-fish-rebound/ Also available through the podcast https://itunes.apple.com/us/podcast/60-second-science/id189330872?mt=2