Native Plant Growth and Seedling Establishment in Soils Influenced by Bromus Tectorum

• Published in: Rangeland ecology & management 2008-11, Vol.61 (6), p.630-639
• Main Authors: Rowe, Helen I., Brown, Cynthia S.
• Format: Article
• Language: English
• Subjects: altitude; arbuscular mycorrhizal fungi; botanical composition; Bromus tectorum; Changes; cheatgrass; crop-weed competition; ecosystems; Flowers & plants; Forbs; glyphosate; grass weeds; grasslands; Indicator plants; indigenous species; invasions; microbial colonization; mycorrhizal fungi; Native plants; Native species; plant competition; plant establishment; plant growth; Plant roots; Plant succession; Plants; Research Papers; Rocky Mountain National Park; Seeding; Seedlings; semiarid zones; soil microorganisms; Soil treatment; Soils; sporulation; Training devices; vegetation; vegetation cover; vesicular arbuscular mycorrhizae; weed control; wildfires
• ISSN: 1550-7424; 1551-5028; 1551-5028
• DOI: 10.2111/08-006.1

The invasion of 40 million hectares of the American West by cheatgrass (Bromus tectorum L.) has caused widespread modifications in the vegetation of semi-arid ecosystems and increased the frequency of fires. In addition to well-understood mechanisms by which cheatgrass gains competitive advantage, it has been implicated in reducing arbuscular mycorrhizal fungi (AMF) abundance and taxa diversity. We evaluated this possibility at a high elevation site in a two-pronged approach. To test whether cheatgrass changed native AMF communities in ways that affected subsequent native plant growth, we grew cheatgrass and native plants in native soils and then planted native plants into these soils in a greenhouse experiment. We found that cheatgrass-influenced soils did not inhibit native plant growth or AMF sporulation or colonization. To test whether soils in cheatgrass-dominated areas inhibited establishment and growth of native plants, cheatgrass was removed and six seeding combinations were applied. We found that 14.02 ± 1.7 seedlings · m−2 established and perennial native plant cover increased fourfold over the three years of this study. Glyphosate reduced cheatgrass cover to less than 5% in the year it was applied but did not facilitate native plant establishment or growth compared with no glyphosate. We conclude that cheatgrass influence on the soil community does not appear to contribute to its invasion success in these high elevation soils. It appears that once cheatgrass is controlled on sites with sufficient native plant abundance, there may be few lingering effects to inhibit the natural reestablishment of native plant communities.