Minimal Persistence of Native Bunchgrasses Seven Years after Seeding following Mastication and Prescribed Fire in Southwestern Oregon, USA

[摘要] Seeding of native grasses is widely used to restore plant communities and prevent establishment of introduced species following wildfire and prescribed burns. However, there is a lack of long-term data to evaluate the success of native grass seeding. Here, in the interior valley shrublands of southwestern Oregon, we resurveyed plots that had been masticated and burned, and then seeded with bunchgrasses seven years previously. The prescribed fires had resulted in bare ground that increased opportunities for bunchgrass germination as well as for invasion by introduced plants. After two years, native grass seeding was successful, with increased bunchgrass cover that correlated with decreased cover of introduced species. However, five years later, bunchgrass cover had declined by 80%, and the frequency of plots with bunchgrasses had declined by 60%. Cover of surviving bunchgrasses in year 7 correlated positively with bunch-grass cover in year 2 (R2 = 0.34; P = 0.003). Seven years after prescribed fire and seeding, native cover, introduced cover, and species richness were unchanged, and bunchgrass persistence was minimal. Basically, seeding following mastication and prescribed burning had a minimal effect. This study highlights the importance of longer-term monitoring to determine the efficacy of seeding treatments.

[学科分类] 生态、进化、行为和系统

[关键词] Achnatherum lemmonii;Bromus carinatus;Elymus glaucus;Festuca roemeri var. klamathensis;long-term monitoring;restoration ecology;southern Oregon chaparral