Comparison of Methods for Estimating Damage by Wild Ungulates on Field Crops

High numbers of large ungulates are locally accompanied by high levels of damage to field crops, causing economic losses and increased costs for the protection of agricultural fields. Quantifying the levels of damage can be problematic, with the degree of accuracy depending on the method used. The aim of this study was to compare the accuracy, workload and cost of four methods commonly used for estimating damage to wheat fields caused by large ungulates (esp. wild boar) in the Czech Republic. The results suggest that the manual processing of aerial photographs ("Uncrewed Aerial Systems [UAS] with Operator Delineation Method") was very laborious and the least accurate method, with a high risk of error. In comparison, the automatic evaluation of aerial images ("UAS Crop Height Method") and the "Ground-Based Assessment" both provided similar results when carefully analyzed and were equally demanding. The "Yield Method", comparing the net yield from damaged and undamaged areas, provided the same result of assessment and was the least laborious, although it does require the existence of comparable areas and for the conditions to be created in advance before the method is used. Equivalent results were achieved by the UAS Crop Height Method, which we recommend using in cases where the Yield Method cannot be applied.