Salt desert seeding trials to inform restoration seed mixes

Abstract

The Bureau of Land Management in partnership with the Upper Colorado Environmental Plant Center tested 16 native species and varieties of grasses, forbs, and shrubs for emergence from seed. Seeds were sown in garden-style plots in degraded salt desert settings with a high cover of invasive species in western Colorado on public lands within McInnis Canyons National Conservation Area, Dominguez Escalante National Conservation Area, and the Grand Junction Field Office. Test sites were dominated by annual weeds: cheatgrass (Bromus tectorum L. [Poaceae]), annual wheatgrass (Eremopyrum triticeum (Gaertn.) Nevski [Poaceae]), Russian thistle (Salsola kali L. [Chenopodiaceae]), and halogeton or saltlover (Halogeton glomeratus (M. Bieb.) C.A. Mey. [Chenopodiaceae]). Several grass species showed early emergence, while some grass and forb species emerged throughout the 4-y study. Emergence in shrub species was limited. Although the use of connectivity modifiers, which are small, metal structures that can break up bare surfaces, slow erosion, and provide shelter for seeds and seedlings, did not generally increase seedling emergence, they did increase emergence rates of 1 forb species known as mesa pepperwort (Lepidium alyssoides A. Gray [Brassicaceae]) by 248%. Providing structure for seedlings may be an important tool in increasing seeding success in restoration settings. The use of native seed in restoration efforts on arid lands can increase restoration success. In this study, we show that seeded native plant materials are capable of emerging in degraded salt desert settings over time, that some forb species may take longer to germinate, and that seed mixes should include a variety of species to accomplish short- and long-term goals. Our research also highlights the need for longer-term monitoring of native plant materials after seeding.