Get reliable science

Vegetation recovery following wildfire in the Great Basin is often hampered by lack of fire-resilient perennials and the presence of invasive annuals such as cheatgrass. To protect soil resources and reduce weed invasion, burned areas are frequently seeded with native and/or non-native perennial plants. The question of which species to seed is relevant for both short-term rehabilitation objectives as well as long-term management objectives which may include wildlife habitat improvement and restoration of pre-fire vegetation. To better understand long-term effects of post-fire seeding on vegetation recovery and succession, we revisited study sites in Tintic Valley, Utah, where seeding experiments had been initiated following a 1999 wildfire. Four different seed mixes, including two comprised entirely of native species, had been applied using rangeland drills at a shrubland site and aerial seeding plus chaining at a woodland site. New vegetation data collected in 2015-2017 revealed changes relative to the early post-fire period (2000-2002). We found significant increases in overall cover of seeded species although the relative differences between treatments did not change. Some seeded species, particularly rhizomatous grasses, increased while others declined. Cheatgrass increased in some of the treatments, especially the unseeded control and to a lesser extent the treatments where only native species had been seeded. The non-native seeded species were more effective than native species at suppressing cheatgrass, but the non-natives also had the undesirable effect of inhibiting shrub establishment. Our results indicate that post-fire seeding has lasting effects on vegetation composition and structure, implying that seed mixes should be carefully formulated to promote long-term management objectives.