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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #344730
Title: Functional differences betwen native bunchgrasses and the invasive grass Bromus tectorum

Author
item HE, HUIQIN - Yibin University
item Monaco, Thomas
item Jones, Thomas

Submitted to: Frontiers of Agricultural Science and Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2017
Publication Date: 3/1/2018
Citation: He, H., Monaco, T.A., Jones, T.A. 2018. Functional differences betwen native bunchgrasses and the invasive grass Bromus tectorum. Frontiers of Agricultural Science and Engineering. 5:139-147.

Interpretive Summary: We conducted 30- and 60-day greenhouse experiments to compare functional traits of Bromus tectorum (invasive annual grass) and three perennial bunchgrass species under well watered or drought conditions. Even under drought, B. tectorum experienced significantly less stress (i.e., higher xylem pressure potential and greater shoot water content, water use per day, water use efficiency) and biomass production than the perennial grasses after 30 d. However, after 60 d, its superiority was reduced under infrequent watering. Differences among perennial grasses were more pronounced for physiological traits under infrequent watering and for morphological traits under frequent watering. Elymus multisetus (fast-growing species) had a higher transpiration rate, lower leaf temperature, and lower water use efficiency than all species after 30 d. In contrast, Pseudoroegneria spicata (slow growing) had lower xylem pressure potential and higher leaf temperature than all species under infrequent watering. Under frequent watering, shoot dry mass and specific leaf area of B. tectorum was matched by Elymus wawawaiensis (moderate-growing species), which was usually more productive than the other bunchgrasses. These traits indicate fundamental differences in drought response and suggest a few mechanistic avenues to improve establishment success of perennial grasses under competition with B. tectorum in shrub-steppe restoration settings.

Technical Abstract: We conducted 30- and 60-day greenhouse experiments to compare functional traits of Bromus tectorum (invasive annual grass) and three perennial bunchgrass species under well watered or drought conditions. Even under drought, B. tectorum experienced significantly less stress (i.e., higher xylem pressure potential and greater shoot water content, water use per day, water use efficiency) and biomass production than the perennial grasses after 30 d. However, after 60 d, its superiority was reduced under infrequent watering. Differences among perennial grasses were more pronounced for pysiological traits under infrequent watering and for morphological traits under frequent watering. Elymus multisetus (fast-growing species) had a higher transpiration rate, lower leaf temperature, and lower water use efficiency than all species after 30 d. In contrast, Pseudoroegneria spicata (slow-growing) had lower xylem pressure potential and higher leaf temperature than all species under infrequent watering. Under frequent watering, shoot dry mass and specific leaf area of B. tectorum was matched by Elymus wawawaiensis (moderate-growing species), which was usually more productive than the other bunchgrasses. These traits indicate fundamental differences in drought response and suggest a few mechanistic avenues to improve establishment succesful perennial grasses under competition with B. tectorum in shrub-steppe restoration settings.