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Title: Optimal prescribed burn frequency to manage foundation California perennial grass species and enhance native flora

Grasslands can be diverse assemblages of grasses and forbs but not much is known how perennial grass species management affects native plant diversity except in a few instances. We studied the use of late-spring prescribed burns over a span of 11 years where the perennial grass Poa secunda was the foundation species, with four additional years of measurements after the final burn. We also evaluated burn effects on P. secunda, the rare native annual forb Amsinckia grandiflora and local native and exotic species. Annual burning maintained P. secunda number, resulted in significant expansion, the lowest thatch and exotic grass cover, the highest percentage of bare ground, but also the lowest native forb and highest exotic forb cover. Burning approximately every 3 years maintained a lower number of P. secunda plants, allowed for expansion, and resulted in the highest native forb cover with a low exotic grass cover. Burning approximately every 5 years and the control (burned once from a wildfire) resulted in a decline in P. secunda number, the highest exotic grass and thatch cover and the lowest percentage of bare ground. P. secunda numbers were maintained up to 4 years after the final burn. And while local native forbsmore » benefited from burning approximately every 3 years, planted A. grandiflora performed best in the control treatment. A. grandiflora did not occur naturally at the site; therefore, no seed bank was present to provide across-year protection from the effects of the burns. Thus, perennial grass species management must also consider other native species life history and phenology to enhance native flora diversity.« less
 [1] ;  [2] ;  [3] ;  [4]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Biosciences and Biotechnology Dept.
  2. USDA-ARS Northern Plains Agricultural Research Lab., Sidney (United States). Pest Management Research Unit
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Environmental Functional Area
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Computations Dept.
Publication Date:
Report Number(s):
Journal ID: ISSN 0960-3115; PII: 1376
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Biodiversity and Conservation
Additional Journal Information:
Journal Volume: 26; Journal Issue: 11; Journal ID: ISSN 0960-3115
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; 60 APPLIED LIFE SCIENCES; Native California forbs; Native California grasses; Perennial grassland restoration; Enhancing native flora
OSTI Identifier: