Johnson, H.E., J.W. Fischer, M Hammond, P. Dorsey, W. D. Walter, C.W. Anderson, and K.C. VerCauteren. 2014. Evaluation of techniques to reduce deer and elk damage to agricultural crops. Wildlife Society Bulletin 38(2):358–365.
Mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus nelsoni) provide important recreational, ecological, and economic benefits, but can also cause substantial damage to agricultural crops. Cervid damage to agriculture generates significant challenges for wildlife agencies responsible for minimizing crop depredation while maintaining healthy deer and elk populations. Sunflower producers in southwestern Colorado have experienced high deer and elk damage in recent years and were interested in temporary methods to reduce damage that were cost-effective for rotational crops. To address this challenge we investigated three temporary, non-lethal exclusion and repellent techniques for reducing deer and elk damage to sunflowers: 1) a polyrope electric fence, 2) the chemical repellent Plantskydd™, and 3) a winged fence. During July through October 2011 and 2012, we used a randomized block design to test the efficacy of these techniques by quantifying cervid damage to sunflowers and the number of deer and elk tracks traversing treatment and control plot boundaries. Using generalized linear mixed models we found that polyrope electric fences significantly reduced deer and elk damage and presence within plots, while the repellent and winged fences did not have significant treatment effects. In areas where wildlife management agencies want to maintain or increase deer and elk populations but reduce seasonal damage by cervids to agriculture, use of an effective exclusion technique like polyrope electric fence could sufficiently protect high-value crops, decrease the need for lethal depredation permits and damage compensation payments, and increase satisfaction among producers and the public.