Calibrating the data logger…
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 synchronously at two or more sites on average every 23.6 years, consistent with spread between sites. Most (70%) of the historical fires burned in the early growing season when strong winds can spread fire through sagebrush. Recent burns, relative to unburned sites exhibited greater reductions in sagebrush ( Artemisia tridentata ; 27% vs. 6%) and concomitant increases in herbaceous (40% vs. 55%) cover. These differences declined with time since fire but persisted for at least two decades. Burns were dominated by a suite of native perennial grasses, forbs, and a re-sprouting shrub species. Historically, such openings may have served as seasonal GUSG habitat. Burns exhibited slightly increased cover (4% vs. 1%) of a widely-planted non-native perennial grass, crested wheatgrass ( Agropyron cristatum ). Our results suggest that parts of the UGB sagebrush landscapes were characterized historically by frequent fire and dynamic vegetation mosaics that included open, grassy patches. These findings are consistent with the use of prescribed fire to restore and maintain this ecological process and vegetation heterogeneity. However, the contemporary context for fire has changed, and now includes substantially reduced (Endangered Species Act) ESA-listed GUSG populations, increased risk of non-native plant invasion, and climate warming. These circumstances highlight new risks, information needs, and opportunities for key knowledge co-production via management-research partnerships.
Knowledge graph centered on Data from: Historical fire regimes and contemporar with 36 nodes and 205 connections. Top connected: Artemisia, A. tridentata, Artemisia tridentata, native species, woody stems.
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