Postfire Seeding and Plant Community Recovery in the Great Basin

Abstract

As wildland fire frequency increases around the globe, a better understanding of the patterns of plant community recovery in burned landscapes is needed to improve rehabilitation efforts. We measured establishment of seeded species, colonization of Bromus tectorum and other nonnative annual plants, and recovery of nonseeded native species in topographically distinct areas within five fires that burned Great Basin shrub-steppe communities in Elko County, Nevada. Plant density, frequency, and cover data were collected annually for 4 yr postfire. Vegetation composition varied among flat areas and north- and south-facing
aspects, and changed over the course of the sampling period; recovery varied among sites. In general, B. tectorum densities were higher on south aspects, particularly 3 and 4 yr after fire, when densities increased dramatically relative to prefire conditions. Nonseeded native perennial grasses, forbs, and shrubs were abundant in three of the five fire sites, and were more likely to be present on north aspects and flat areas. Over time, nonseeded perennial grass densities remained relatively constant, and nonseeded forbs and shrubs increased. Seeded species were most likely to establish in flat areas, and the density of seeded
perennial grasses, forbs, and shrubs decreased over time. Frequency and density measurements were highly correlated, especially for perennial species. Our results emphasize the value of considering site aspect and the potential for native regrowth when planning and monitoring restorations. For example, effective rehabilitation of south aspects may require the development of new restoration methods, whereas north aspects and flat areas in sites with a strong native component were not improved by the addition of seeded species, and may require weed control treatments, rather than reseeding, to improve recovery. Tailoring
revegetation objectives, seed mixes, seeding rates, and monitoring efforts to conditions that vary within sites may lead to more cost effective and successful restoration.