Dirac Twidwell

Associate Professor

Area of Expertise: Range and Forage Sciences

B.S., Biological Sciences, Missouri University of Science and Technology (formerly University of Missouri-Rolla), 2003.

M.S., Rangeland Ecology and Management, Oklahoma State University, 2006.

Ph.D., Ecosystem Science and Management, Texas A&M University, 2012.

Area of Focus

  • Rangeland Ecology
  • Fire Ecology
  • Applied Ecology

Research Interests

  • Social-ecological resilience to extreme disturbance (e.g. fire) and climatic events
  • Resilience, hysteresis, and thresholds in alternative states and their applications in ecosystem management
  • Trade-offs of changing land use and disturbance regimes in coupled human-natural systems
  • Forecasting threats to biodiversity and ecosystem services
  • Disaster avoidance and wildfire management at the rangeland-urban interface
  • Integration of science in natural resource policy and management

Courses Taught


  • Twidwell, D., W.E. Rogers, C.L. Wonkka, C.A. Taylor, Jr., U.P. Kreuter. 2016. Extreme prescribed fire during drought reduces survival and density of woody resprouters. Journal of Applied Ecology. DOI: 10.1111/1365-2664.12674
  • Breshears, D.D., A.K. Knapp, D.J. Law, M.D. Smith, D. Twidwell, C.L. Wonkka. Rangeland responses to predicted increases in drought extremity. Rangelands [Invited submission] Accepted.
  • Krueger, E., T. Ocshner, D.M. Engle, J.D. Carlson, D. Twidwell, S.D. Fuhlendorf. Concurrent and antecedent soil moisture relate positively or negatively to probability of large wildfires depending on season. International Journal of Wildland Fire. DOI: 10.1071/WF15104
  • Weir, J.R., D. Twidwell, C.L. Wonkka. From grass roots to national alliance: the emerging trajectory of prescribed burn associations. Rangelands. DOI:10.1016/j.rala.2016.02.005
  • Wonkka, C.L., D. Twidwell, J.B. West, W.E. Rogers. 2016. Shrubland resilience varies across soil types: implications for operationalizing resilience in ecological restoration. Ecological Applications 26:128-145.
  • Twidwell, D., A.S. West, W.B. Hiatt, A.L. Ramirez, J.T. Winter, D.M. Engle, S.D. Fuhlendorf, J.D. Carlson. 2016. Plant invasions or fire policy: which has altered fire behavior more in tallgrass prairie? Ecosystems 19:356-368.
  • Twidwell, D., C.L. Wonkka, M.T. Sindelar, J.R. Weir. 2015. First approximations of prescribed fire risks relative to other management techniques used on private lands. PLOS ONE 10:e0140410.
  • Krueger, E., T. Ocshner, D.M. Engle, J.D. Carlson, D. Twidwell, S.D. Fuhlendorf. 2015. Soil moisture affects growing season wildfire size in the southern Great Plains. Soil Science Society of America Journal 79:1567-1576.
  • Allred, B.W., W.K. Smith, D. Twidwell, J.H. Haggerty, S.J. Running, D.E. Naugle, S.D. Fuhlendorf. 2015. Ecosystem services lost to oil and gas in North America. Science 348:401-402.
  • Allred, B. W., D. Twidwell, S.D. Fuhlendorf. 2014. The interaction of climate change, land cover, and political representation in the USA. Ecosphere 5:art159.
  • Twidwell, D., C.L. Wonkka, C.A. Taylor, Jr., C.B. Zou, J.J. Twidwell, W.E. Rogers. 2014. Drought-induced woody plant mortality in an encroached savanna depends on topoedaphic factors and land management. Applied Vegetation Science 17:42-52.
  • Twidwell, D., J.M. Meza, C.J. Turney, W.E. Rogers. 2014. Does prescribed fire facilitate fire ant invasions in coastal prairies or aid management by improving mound search efforts? Southeastern Naturalist 13:93-104.
  • Twidwell, D., B.W. Allred, S.D. Fuhlendorf. 2013. National-scale assessment of ecological content in the world's largest land management framework. Ecosphere 4:art94.
  • Twidwell, D., W.E. Rogers, S.D. Fuhlendorf, C.L. Wonkka, D.M. Engle, J.R. Weir, U.P. Kreuter, C.A. Taylor, Jr.2013. The rising Great Plains fire campaign: citizens' response to woody plant encroachment. Frontiers in Ecology and the Environment 11:e64-e71.
  • Twidwell, D., S.D. Fuhlendorf, C.A. Taylor, Jr., W.E. Rogers. 2013. Refining thresholds in coupled fire-vegetation models to improve management of encroaching woody plants in grasslands. Journal of Applied Ecology 50:603-613.
  • Twidwell, D., W.E. Rogers, B. McMahon, B. Thomas, U.P. Kreuter, T.L. Blankenship. 2012. Prescribed extreme fire effects on richness and invasion in coastal prairie. Invasive Plant Science and Management 5:330-340.
  • Taylor, C.A., Jr., D. Twidwell, N.E. Garza, C. Rosser, J.K. Hoffman, T.D. Brooks. 2012. Long-term effects of fire, livestock herbivory removal, and weather variability in Texas semiarid savanna. Rangeland Ecology and Management 65:21-30.
  • Twidwell, D., S.D. Fuhlendorf, D.M. Engle, C.A. Taylor, Jr. 2009. Surface fuel sampling strategies: linking fuel measurements and fire effects. Rangeland Ecology and Management 63:223-229.
  • Huang, Y.W., D. Twidwell, J. Elrod.  2003.  Occurrence and effects of EDCs in the environment.  in: Endocrine Disrupting Compounds in the Environment, ed. C. Adams and A. Bhandari.  ASCE Hazardous, Toxic, and Radioactive Waste Management (HTRWM) Practice Periodical 7:241-252. 

Non-Refereed Publications

  • Starns, H. D., S. D. Fuhlendorf, R. D. Elmore, T. J. Hovick, D. Twidwell, E. T. Thacker. 2015. Patch-burning to manage prairie-chicken habitat and rangeland fuels. Grouse News. 49:18-20.
  • D. Twidwell, B.W. Allred, S.D. Fuhlendorf. 2014. Summary of a national-scale synthesis of the Ecological Site Description (ESD) Database. Rangelands 36:13-17.
  • Taylor, C.A., D. Twidwell, R.Q. Landers, and K. Mills. 2005. Fire ecology in the central Texas and Edwards Plateau regions of Texas. in: Fire as a tool for managing wildlife habitat in Texas, ed. C.G. Brown and D. Rollins. Texas Cooperative Extension, San Angelo, USA, 32-41.  

Outreach Publications, Reports and Commodity Newsletters

  • Schumacher K., C.L. Wonkka, D. Twidwell, J. Volesky. 2016. Prairie dog legislation and burrowing owls in Nebraska. UNL Extension EC1785.
  • Simonsen, V. J.E. Fleischmann, D. Whisenhunt, J. Volesky, D. Twidwell. 2015. Act now or pay later: evaluating the cost of reactive versus proactive Eastern redcedar management. UNL Extension EC1784.
  • Thacker, E., D. Twidwell. 2014. Synthesis of the effect of fire on lesser prairie chickens. Great Plains Fire Science Exchange, GPE Publication 2014-6, 7 pp.
  • Twidwell, D. 2014. Loss of fire, juniper encroachment, and ecosystem services in grasslands. (vol. 20). Center for Grassland Studies. 1 pp.
  • Young, S., and D. Twidwell. 2014. Prescribed fire for grassland management. Crop Production Clinic Proceedings. University of Nebraska - Lincoln. pp. 167-169.

Agency Partners

Nebraska Game and Parks logo
Nebraska Cooperative Fish & Wildlife Research Unit logo
The Nature Conservancy logo
SERDP logo
FireScience.gov logo

Great Plains Fire Science Exchange logo

Nebraska Forest Service logo