What Seeds to Plant in the Great Basin? Comparing Traits Prioritized in Native Plant Cultivars and Releases with those that Promote Survival in the Field

Abstract

Restoration in the Great Basin is typically a large-scale enterprise, with aerial, drill, and broadcast seeding of perennial species common after wildfires. Arid conditions and invasive plants are significant barriers to overcome, but relatively simple changes to seeds used for restoration may improve success. Here we summarize: 1) the composition of seed mixes used in recent postfire seedings in Nevada, 2) traits that were valued when cultivars and other native seed materials were named and released, and 3) traits that have been demonstrated to increase native perennial grass performance in invaded systems. A review of 420 seeding treatments on public shrublands in Nevada between 2006 and 2009 indicated that native perennial grasses and native shrubs were most frequently included in these projects, followed by exotic and native forbs, and lastly, exotic perennial grasses. Native perennial grasses made up the bulk of seeds used in these treatments, with multiple species of grasses (average of 3.4 species) typically seeded per treatment, while the richness of other functional groups in seed mixes was closer to 1 species per treatment. Traits prioritized in cultivars and native seed material releases included, in order of frequency: forage quality and yield, seed yield, seedling vigor, ability to establish and persist, and drought tolerance, with many other traits mentioned with less frequency. Traits that had consistent support for improving native perennial grass performance in the field were related to early phenology, small size, and higher root allocation. Further tests to determine which traits improve shrub and forb establishment under field conditions could further refine seed source selection, and help maintain diversity in Great Basin systems.