Fire Influences Patch Selection by Cattle More Strongly than Previous Grazing Events

Understanding where animals graze and why they choose to graze there can be critical to rangeland and ecosystem management with misunderstandings of grazing distribution and behavior often being detrimental to management goals. Over time, grazing animals create grazing lawns that attract grazing animals due to ease of accessibility to more palatable regrowth. Similarly, fire can defoliate large areas of vegetation and promote new plant growth that is preferentially grazed by herbivores (i.e., pyric-herbivory in a patch-burn grazing framework). Grazer distribution in pyric-herbivory studies has been tracked through various metrics that produce valuable data. However, these data often lack precise information on what animals consume and do not account for differential plant production, limiting our ability to understand and apply pyric-herbivory to rangeland management through patch-burn grazing. Simultaneously monitoring plant biomass production and livestock grazing utilization would be the most comprehensive method to show site selection by grazing animals. To examine how previous grazing events influence grazing patterns, we collected data over 3 years on the utilization rate of patches by cattle in patch-burn grazing pastures and compared them to utilization rates in season-long grazed pastures. We found that regardless of management, grazing patterns were influenced by grazing in prior years. However, grazing in patch-burn pastures was more strongly influenced by fire than previous grazing events. Our results suggest that in the absence of additional disturbances, grazing patterns from previous years influence grazing patterns in the current year. However, disturbances that remove dead vegetation and promote regrowth, such as fire, override the influence of previous grazing patterns, modifying patch selection. Moving forward, these disturbances can be used to negate the effect of established grazing lawns and promote targeted grazing in areas with fresh regrowth, which benefits management goals.