Drought Response of Invasive Yellow Starthistle (Centaurea solstitialis, Asteraceae) in Relation to Serpentine Soils

Publication Date

5-10-2024

Document Type

Article

Publication Title

Western North American Naturalist

Volume

84

Issue

1

DOI

10.3398/064.084.0101

First Page

1

Last Page

10

Abstract

Invasive species have altered ecosystems throughout the world. Centaurea solstitialis (yellow starthistle, Asteraceae) is noted as one of the most problematic invasive species in the United States, where it has invaded most states. In the western United States, it is becoming more prevalent on the margins of previously hardtoinvade edaphic communities that are critical habitat for many threatened species. The goal of this study was to evaluate the role of soil type (serpentine vs. nonserpentine) and soil moisture in C. solstitialis invasion. We used a field study to compare water relations of C. solstitialis with the native, serpentinetolerant Hemizonia congesta subsp. luzulifolia (tarweed; Asteraceae). Additionally, we used a greenhouse experiment with controlled water treatments to examine physiological function of C. solstitialis in both serpentine and nonserpentine soils. In the field study, we found that C. solstitialis exhibited lower wateruse efficiency and lower midday water potential than the native H. congesta, even though both species had access to similar levels of soil moisture. In the greenhouse, we observed lower wateruse efficiency and lower midday water potential for C. solstitialis in serpentine as compared to nonserpentine soils. However, soil moisture had a greater overall impact on plant physiology than on soil type. Our results indicate that C. solstitialis exhibits growth strategies consistent with drought escape by growing quickly and tolerating high levels of water loss. As a result, this strategy may enable it to invade and succeed in some edaphic soil environments.

Department

Biological Sciences

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