Historical fire regimes and contemporary fire effects within sagebrush habitats of Gunnison Sage-grouse

The historical role of fire in sagebrush (Artemisia tridentata) landscapes remains poorly understood yet is important to inform management and conservation of obligate species such as the threatened Gunnison Sage-grouse (GUSG; Centrocercus minimus). We reconstructed fire histories from tree-ring fire-scars at sagebrush-forest ecotones (10 sites, 111 trees) to better understand the role of fire in sagebrush landscapes of the Upper Gunnison Basin (UGB), Colorado, and how fire may have changed following European-American settlement. We assessed likely influences of historical fire by surveying plant composition and structure at 100 sagebrush sites with and without recent (2001–2020) fire. 
Tree-ring fire-scars revealed a history of repeated low-severity fire at sagebrush-forest ecotones until 1892, followed by over a century without fire. Between 1684 and 1892, the mean fire interval (MFI) among sites averaged 41.3 years (ranging from 18.2 to 79.7 years). Fire over this period occurred syn..., Sagebrush fire effects: field methods
We characterized fire effects on sagebrush vegetation in the UGB, from vegetation surveys in 50 recently burned and 50 adjacent, unburned sagebrush sites (Figure 1). Fire perimeter polygons were obtained from local US Forest Service (USFS) and Bureau of Land Management (BLM) offices, and included both prescribed burns and wildfires. Burned sites were sampled across 12 different fires occurring in eight different years between 2001 and 2021, facilitating a comparison of vegetation composition across a chronosequence of time-since-fire. We excluded from sampling any burns that were subject to post-fire management including reseeding or planting of sagebrush. Sites were randomly distributed within fire perimeters and adjacent areas within 100 m of fire perimeters. For every burned site we sampled, an unburned site was sampled directly adjacent to the fire perimeter (Figure 1). All sites were within occupied GUSG habitat or directly adjacent to occupied..., Excel and/or RStudio.