Long-Term Trends of Annual Herbaceous Expansion in the Nebraska Panhandle: Rangeland Analysis Platform Data

Abstract

Summary with Implications This descriptive analysis evaluated changes in Annual Forb and Grass (AFG) herbaceous cover in the Nebraska Panhandle from 1986 to 2023 using the Rangeland Analysis Platform (RAP). It was hypothesized that AFG herbaceous cover would show an increasing trend over time, indicating the potential expansion of the annual invasive cheatgrass (Bromus tectorum). County-level RAP data were used to calculate long-term means as an indicator. Results showed an increase in AFG cover across the region. Trends were cyclical, with cover peaking and dipping over time, but the overall trajectory showed increases in AFG in the Panhandle. The increasing dominance of annual herbaceous cover, such as cheatgrass, has significant implications for forage availability, timing, and quality, as well as long-term ecological sustainability. This spatiotemporal analysis provides a better understanding of the potential threat of invasive annual forbs and grasses on rangelands in the Nebraska Panhandle