Photo of Bret OlsonProfessor of Range Ecology
313 Animal Bioscience Building; MSU-Bozeman 
Bozeman, MT 59717 
Phone: (406) 994-3721 
Fax: (406) 994-5589 
Email: bolson@montana.edu

Education

  • B.A. University of California, Berkeley, Botany, 1977
  • M.S. University of California, Berkeley, Range Management, 1982
  • Ph.D. Utah State University, Range Ecology, 1987

Classes

  • NRSM 240 Natural Resource Ecology
  • NRSM 453 Habitat Inventory and Analysis
  • ARNR 541 Range Ecophysiology

Research Interests

  • Determine how livestock use the landscape on winter range.
  • Develop effective grazing recommendations for controlling noxious weeds.
  • Determine metabolic rates and heart rates of beef cattle as they change seasonally, and in response to different management scenarios.

Accomplishments and Interests

  • Assessed cattle use patterns on winter range to identify how to minimize weight loss
  • Identified effects of sheep grazing on two noxious weeds in Montana, using several approaches from basic plant biology to animal behavior and nutrition
  • Conducted a unique, longterm study to assess effects of livestock grazing on grasshoppers, and cumulative effects of livestock grazing and grasshopper herbivory on plant communities
  • Used the stable 13C isotope as a tracer to assess carbon allocation in plants, and used background levels of 13C/12C in plant tissues to indicate water use efficiency of leafy spurge and spotted knapweed and native grasses
  • Using 15N isotope as a tracer to assess N uptake in spotted knapweed and native plants
  • Conduct studies and develop models that indicate the importance of solar radiation for the thermal balance beef cattle grazing winter rangeland

Recent Publications

  • O'Neill, K. M., Olson, B. E., Wallander, R. T., Rolston, M. G., Seibert, C. E.  2010.  Effects of livestock grazing on grasshopper abundance on a native rangeland in Montana.  Environ. Ento.  39:775-786.
  • Whitney, T. R., Olson, B. E.  2010.  Can sheep and cattle rumen microorganisms be conditioned to invasive weeds?  Sheep and Goat Res. J.  25:26-31.
  • O’ Neill, K. M., S. Blodgett, B. E. Olson, and R. S. Miller.  2008.  Impact of livestock grazing on abundance of Miridae and Reduviidae (Hemiptera) in crested wheatgrass pastures.  J. Econ. Entom.  101:309-313.
  • Thrift, B. D., J. C. Mosley, T. K. Brewer, B. L. Roeder, B. E. Olson, and R. W. Kott.  2008.  Prescribed sheep grazing to suppress spotted knapweed on foothill rangeland.  Rangeland Ecol. Manage.  61:18-25.
  • Keren, I. N. and Olson, B. E.  2007.  Applying thermal imaging software to cattle grazing winter range.  J. Ther. Biol.  32:204-211.
  • Whitney, T. R. and Olson, B. E.  2007.  Will molasses or conditioning increase consumption of spotted knapweed by sheep?  Rangeland Ecol. Manage.  60:533-537.
  • Hill, J. P., Germino, M. J., Wraith, J. M., Olson, B. E., Swan, M. B.  2006.  Advantages in water relations contribute to greater photosynthesis in Centaurea maculosa compared with established grasses.  Inter. J. Plant Sci.  167:269-277.
  • Keren, I. N., and Olson, B. E.  2006.  Thermal balance of cattle grazing winter range: model development.  J. Ther. Biol.  31:371-377.
  • Keren. I. N., and Olson, B. E.  2006.  Thermal balance of cattle grazing winter range: model application.  J. Anim. Sci.  84:1238-1247.
  • Whitney, T. R., and Olson, B. E.  2006.  Conditioning ewes and lambs to increase consumption of spotted knapweed.  Appl. Anim. Behav. Sci.  100:193-206.
  • Olson, B. E., and K. Launchbaugh.  2006.  Managing herbaceous broadleaf weeds with targeted grazing.  In:  Targeted grazing: A natural approach to vegetation management and landscape enhancement.  pp 32-39.  American Sheep Industry Association
  • Henderson, J., and B. E. Olson.  2006.  Understanding plant response to grazing.  In:  Targeted grazing: A natural approach to vegetation management and landscape enhancement.  pp 58-67.  American Sheep Industry Association
  • Hook, P. B., Olson, B. E., and Wraith, J. M.  2004.  Effects of the invasive forb Centaurea maculosa on grassland carbon and nitrogen pools in Montana, USA.  Ecosystems  7:686-694.
  • Blicker, P. S., Olson, B. E., and Wraith, J. M.  2003.  Water use and water use efficiency of spotted knapweed and three native grasses.  Plant Soil  254:371-381.
  • O’ Neill, K. M., Olson, B. E., Rolston, M. G., Wallander, R. T., Larson, D. P., and Seibert, C. E.  2003.  Effects of livestock grazing on rangeland grasshopper (Orthoptera: Acrididae) abundance.  Agriculture, Ecosystems and Environment  97:51-64.
  • Olson, B. E., and Blicker, P. S.  2003.  Response of the invasive Centaurea maculosa and two native grasses to N-pulses.  Plant Soil  254:457-467.
  • Olson, B. E., and Wallander, R. T.  2003.  Comparing indicators of sheep grazing leafy spurge and perennial grasses.  Sheep and Goat Res. J.  18:101-108.
  • Sperber, T. D., Wraith, J. M., and Olson, B. E.  2003.  Soil physical properties associated with the invasive spotted knapweed and native grasses are similar.  Plant Soil  252:241-249.
  • Blicker, P. S., and Olson, B. E., and Engel, R.  2002.  Traits of the invasive Centaurea maculosa and two native grasses: effect of N supply.  Plant and Soil  247:261-269.
  • Olson, B. E., and Wallander, R. T.  2002.  Does ruminal retention time affect leafy spurge seed of varying maturity?  J. Range Manage.  55:65-69.
  • Olson, B. E., and Wallander, R. T.  2002.  Effects of invasive forb litter on seed germination, and seedling growth and survival.  Basic and Applied Ecology  3:309-317.
  • Olson, B. E., and Wallander, R. T.  2002.  Influence of winter weather and shelter on activity patterns of beef cows.  Can. J. Anim. Sci.  82:491-501.
  • Olson, B. E., and Wallander, R. T.  2001.  Sheep grazing of spotted knapweed and Idaho fescue.  J. Range Manage.  54:25-30
  • Olson, B. E., Wallander, R. T., and Beaver, J. M.  2000.  Comparing nondestructive measures of forage structure and phytomass.  Can. J. Plant Sci.  80:565-573.
  • Olson, B. E., Wallander, R. T., and Paterson, J. A.  2000.  Do windbreaks minimize stress on cattle grazing foothill winter range?  Can. J. Anim. Sci.  80:265-272.