Beaver Loggers: Beaver Herbivory Alters Forest Structure

  • Carol A. Johnston


Beavers engineer forests by cutting trees for dam construction and winter forage. Beavers are the only North American animal besides humans that can fell mature trees. Our studies at Kabetogama and Duluth, Minnesota confirmed beavers’ preference for trembling aspen, Populus tremuloides. Near the Duluth beaver ponds, beavers traveled more than twice as far to obtain trembling aspen as they did to obtain speckled alder (Alnus incana), a species which they avoided relative to its abundance in the riparian zone. We analyzed several boreal tree species for secondary metabolites that might make them unpalatable to beavers. Mature trembling aspen twigs had lower concentrations of phenolics in comparison to most other common boreal tree species, including its sibling, Populus balsamifera. The compounds tested did not explain beaver avoidance of speckled alder, however. Selective foraging by beavers within 50 m of their pond edges significantly decreased forest stem density and altered tree species composition, creating a “bathtub ring” of avoided conifers (Abies balsamea, Picea glauca) around the pond that was confirmed by GIS analysis of a forest cover map of the Kabetogama Peninsula.


Browse Cache Central place foraging Conifer Herbivory Morticulture Woody plant Phenolic Plant metabolite Populus tremuloides Riparian forest Salix Selectivity Silviculture Terpene Tree cutting 


  1. Aldous SE (1938) Beaver food utilization studies. J Wildl Manag 2(4):215–222CrossRefGoogle Scholar
  2. Allen B, Salés J, Bonde J, Meysembourg P, Johnston CA (1993) Effects of past disturbance on present-day forests at Voyageurs National Park. In: ARC/INFO maps 1992. Environmental Systems Research Institute, Redlands, p 63Google Scholar
  3. Anderson CB, Pastur GM, Lencinas MV, Wallem PK, Moorman MC, Rosemond AD (2009) Do introduced North American beavers Castor canadensis engineer differently in southern South America? An overview with implications for restoration. Mammal Rev 39(1):33–52CrossRefGoogle Scholar
  4. Bailey JK, Schweitzer JA, Rehill BJ, Lindroth RL, Martinsen GD, Whitham TG (2004) Beavers as molecular geneticists: a genetic basis to the foraging of an ecosystem engineer. Ecology 85(3):603–608CrossRefGoogle Scholar
  5. Barnes DM, Mallik AU (1996) Use of woody plants in construction of beaver dams in northern Ontario. Can J Zool 74(9):1781–1786CrossRefGoogle Scholar
  6. Barnes DM, Mallik AU (2001) Effects of beaver, Castor canadensis, herbivory on streamside vegetation in a northern Ontario watershed. Can Field-Nat 115(1):9–21Google Scholar
  7. Barnes WJ, Dibble E (1988) The effects of beaver in riverbank forest succession. Can J Bot 66:40–44CrossRefGoogle Scholar
  8. Basey JM, Jenkins SH (1995) Influences of predation risk and energy maximization on food selection by beavers (Castor canadensis). Can J Zool 73(12):2197–2208CrossRefGoogle Scholar
  9. Basey JM, Jenkins SH, Busher PE (1988) Optimal central-place foraging by beavers: tree-size selection in relation to defensive chemicals of quaking aspen. Oecologia 76(2):278–282CrossRefPubMedGoogle Scholar
  10. Basey JM, Jenkins SH, Miller GC (1990) Food selection by beavers in relation to inducible defenses of Populus tremuloides. Oikos 59(1):57–62CrossRefGoogle Scholar
  11. Belovsky GE (1984) Summer diet optimization of beaver. Am Midl Nat 111(2):209–222CrossRefGoogle Scholar
  12. Bray JR, Curtis JT (1957) An ordination of the upland forest communities in southern Wisconsin. Ecol Monogr 27:325–349CrossRefGoogle Scholar
  13. Bryant JP, Provenza FD, Pastor J, Reichardt PB, Clausen TP, du Toit JT (1991) Interactions between Woody plants and browsing mammals mediated by secondary metabolites. Annu Rev Ecol Syst 22:431–446CrossRefGoogle Scholar
  14. Busher PE (1996) Food caching behavior of beavers (Castor canadensis): selection and use of woody species. Am Midl Nat 135(2):343–348CrossRefGoogle Scholar
  15. Clarke KR, Gorley RN (2001) PRIMER v6: user manual/tutorial. PRIMER-E, PlymouthGoogle Scholar
  16. Clausen TP, Evans TP, Reichardt PB, Bryant JP (1989) A simple method for the isolation of salicortin, tremulacin, and tremuloiden from quaking aspen (Populus tremuloides). J Nat Prod 52(1):207–209CrossRefGoogle Scholar
  17. Coley PD, Bryant JP, Chapin FS (1985) Resource availability and plant antiherbivore defense. Science 230(4728):895–899CrossRefPubMedGoogle Scholar
  18. Donkor NT, Fryxell JM (1999) Impact of beaver foraging on structure of lowland boreal forests of Algonquin Provincial Park, Ontario. For Ecol Manag 118(1–3):83–92CrossRefGoogle Scholar
  19. Donkor NT, Fryxell JM (2000) Lowland boreal forests characterization in Algonquin Provincial Park relative to beaver (Castor canadensis) foraging and edaphic factors. Plant Ecol 148(1):1–12CrossRefGoogle Scholar
  20. Doucet CM, Fryxell JM (1993) The effect of nutritional quality on forage preference by beavers. Oikos 67(2):201–208CrossRefGoogle Scholar
  21. Easter-Pilcher A (1990) Cache size as an index to beaver colony size in northwestern Montana. Wildl Soc Bull 18(2):110–113Google Scholar
  22. Faber-Langendoen D, Aaseng N, Hop K, Lew-Smith M (2007) Field guide to the plant community types of Voyageurs National Park. U.S. Geological Survey, RestonGoogle Scholar
  23. Fienberg SE (1977) The analysis of cross-classified categorical data. MIT Press, CambridgeGoogle Scholar
  24. Freedman B (1984) The relationship between the aboveground dry weight and diameter for a wide size range of erect land plants. Can J Bot 62(11):2370–2374CrossRefGoogle Scholar
  25. Fryxell JM, Doucet CM (1993) Diet choice and the functional-response of beavers. Ecology 74(5):1297–1306CrossRefGoogle Scholar
  26. Gallant D, Berube CH, Tremblay E, Vasseur L (2004) An extensive study of the foraging ecology of beavers (Castor canadensis) in relation to habitat quality. Can J Zool 82(6):922–933CrossRefGoogle Scholar
  27. Gerwing TG, Johnson CJ, Alström-Rapaport C (2013) Factors influencing forage selection by the North American beaver (Castor canadensis). Mamm Biol Z Säugetierkd 78(2):79–86CrossRefGoogle Scholar
  28. Gibson GG (1957) A study of beaver colonies in southern Algonquin Park, Ontario, with particular reference to the available food. University of Toronto, TorontoGoogle Scholar
  29. Hagerman AE (1987) Radial diffusion method for determining tannin in plant extracts. J Chem Ecol 13(3):437–449CrossRefPubMedGoogle Scholar
  30. Hall JG (1960) Willow and aspen in the ecology of beaver on Sagehen Creek, California. Ecology 41(3):484–494CrossRefGoogle Scholar
  31. Harmon ME (2001) Moving towards a new paradigm for Woody detritus management. Ecol Bull 49:269–278Google Scholar
  32. Hassinger J, Payne J (2008) Dead wood for wildlife. Pennsylvania woodlands no. 7. Pennsylvania State University, University ParkGoogle Scholar
  33. Hatt RT (1944) A large beaver-felled tree. J Mammal 25(3):313CrossRefGoogle Scholar
  34. Herbison B, Rood SB (2015) Compound influences of river damming and beavers on riparian cottonwoods: a comparative study along the Lardeau and Duncan Rivers, British Columbia, Canada. Wetlands 35(5):945–954CrossRefGoogle Scholar
  35. Howard RJ (1982) Beaver habitat classification in Massachusetts. University of Massachusetts, AmhearstGoogle Scholar
  36. Jenkins SH (1975) Food selection by beavers: a multidimensional contingency table analysis. Oecologia 21:157–173CrossRefPubMedGoogle Scholar
  37. Jenkins SH (1979) Seasonal and year-to-year differences in food selection by beavers. Oecologia 44(1):112–116CrossRefPubMedGoogle Scholar
  38. Jenkins SH (1980) A size-distance relation in food selection by beavers. Ecology 61(4):740–746CrossRefGoogle Scholar
  39. Jenkins SH, Busher PE (1979) Castor canadensis. Mamm Species 120:1–8CrossRefGoogle Scholar
  40. Johnston CA, Naiman RJ (1990) Browse selection by beaver: effects on riparian forest composition. Can J For Res 20:1036–1043CrossRefGoogle Scholar
  41. Johnston CA, Windels SK (2015) Using beaver works to estimate colony activity in boreal landscapes. J Wildl Manag 79(7):1072–1080CrossRefGoogle Scholar
  42. Masslich W, Brotherson J, Cates R (1988) Relationships of aspen (Populus tremuloides) to foraging patterns of beaver (Castor canadensis) in the Strawberry Valley of central Utah. West North Am Nat 48(2):250–263Google Scholar
  43. McGinley MA, Whitham TG (1985) Central place foraging by beavers (Castor canadensis): a test of foraging predictions and the impact of selective feeding on the growth form of cottonwoods (Populus fremontii). Oecologia 66:558–562CrossRefPubMedGoogle Scholar
  44. Milligan HE, Humphries MM (2010) The importance of aquatic vegetation in beaver diets and the seasonal and habitat specificity of aquatic-terrestrial ecosystem linkages in a subarctic environment. Oikos 119(12):1877–1886CrossRefGoogle Scholar
  45. Morris DM (2014) Aquatic habitat use by North American moose (Alces alces) and associated richness and biomass of submersed and floating-leaved aquatic vegetation in north-central Minnesota. Lakehead University, Thunder BayGoogle Scholar
  46. Mortenson SG, Weisberg PJ, Ralston BE (2008) Do beavers promote the invasion of non-native Tamarix in the Grand Canyon riparian zone? Wetlands 28(3):666–675CrossRefGoogle Scholar
  47. Müller-Schwarze D, Schulte BA, Sun L, Müller-Schwarze A, Müller-Schwarze C (1994) Red maple (Acer rubrum) inhibits feeding by beaver (Castor canadensis). J Chem Ecol 20(8):2021–2034CrossRefPubMedGoogle Scholar
  48. Northcott TH (1971) Feeding habits of beaver in Newfoundland. Oikos 22:407–410CrossRefGoogle Scholar
  49. Northcott TH (1972) Water lilies as beaver food. Oikos 23(3):408–409CrossRefGoogle Scholar
  50. Parker JD, Caudill CC, Hay ME (2007) Beaver herbivory on aquatic plants. Oecologia 151(4):616–625CrossRefPubMedGoogle Scholar
  51. Peinetti HR, Baker BW, Coughenour MB (2009) Simulation modeling to understand how selective foraging by beaver can drive the structure and function of a willow community. Ecol Model 220(7):998–1012CrossRefGoogle Scholar
  52. Perala DA (1977) Managers handbook for aspen in the north central states. North Central Forest Experiment Station, St PaulGoogle Scholar
  53. Pinkowski B (1983) Foraging behavior of beavers (Castor canadensis) in North Dakota. J Mammal 64(2):312–314CrossRefGoogle Scholar
  54. Raffel TR, Smith N, Cortright C, Gatz AJ (2009) Central place foraging by beavers (Castor canadensis) in a complex lake habitat. Am Midl Nat 162(1):62–73CrossRefGoogle Scholar
  55. Ray AM, Rebertus AJ, Ray HL (2001) Macrophyte succession in Minnesota beaver ponds. Can J Bot 79(4):487–499Google Scholar
  56. Rosenthal GA, Janzen DH (eds) (1979) Herbivores: their interaction with secondary plant metabolites. Academic Press, OrlandoGoogle Scholar
  57. Severud WJ, Belant JL, Windels SK, Bruggink JG (2013a) Seasonal variation in assimilated diets of American beavers. Am Midl Nat 169(1):30–42CrossRefGoogle Scholar
  58. Severud WJ, Windels SK, Belant JL, Bruggink JG (2013b) The role of forage availability on diet choice and body condition in American beavers (Castor canadensis). Mamm Biol Z Säugetierkd 78(2):87–93CrossRefGoogle Scholar
  59. Shelton PC (1966) Ecological studies of beavers, wolves, and moose in Isle Royale National Park, Michigan. Purdue University, LafayetteGoogle Scholar
  60. Smith DW, Trauba DR, Anderson RK, Peterson RO (1994) Black bear predation on beavers on an Island in Lake superior. Am Midl Nat 132(2):248–255CrossRefGoogle Scholar
  61. Smith DW, Tyers DB (2008) The beavers of Yellowstone. Yellowstone Sci 16(3):4–15Google Scholar
  62. Stefen C, Habersetzer J, Witzel U (2016) Biomechanical aspects of incisor action of beavers (Castor fiber L.) J Mammal 97(2):619–630CrossRefGoogle Scholar
  63. Wright JP, Jones CG, Flecker AS (2002) An ecosystem engineer, the beaver, increases species richness at the landscape scale. Oecologia 132(1):96–101CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Carol A. Johnston
    • 1
  1. 1.Department of Natural Resource ManagementSouth Dakota State UniversityBrookingsUSA

Personalised recommendations