Effects of shading on the rare plant species, Physostegia correllii (Lamiaceae) and Trillium texanum (Melanthiaceae)

Journal of the Botanical Research Institute of Texas
By: , and 

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Abstract

Rare plant species that are constrained by shading may be threatened by a lack of natural disturbance that removes overhanging vegetation. The original distribution of the study species Physostegia correllii (Lundell) Shinners included freshwater floodplains of large rivers in the southcentral U.S. (Colorado, Rio Grande, and Mississippi rivers). A second species, Trillium texanum Buckley was found in seep spring baygalls in east-central Texas and extreme northwestern Louisiana. Experiments to determine the effects of shading on P. correllii and T. texanum were conducted using short-term shade cloth treatments (full sunlight vs. 30% shading for 2–3 weeks), and a dryness treatment for T. texanum (moist vs. less moist). Mean height and cover responses of individuals for both species were determined in conservation gardens located in Lafayette, Louisiana. Physostegia correllii grown in shaded environments for 2.5 weeks had shorter mean height than if grown in full sunlight. Half of the shaded plants in shaded plots had died by the mid-summer. For T. texanum, shading reduced the mean height and cover of plants. Therefore, management to remove overhanging ground vegetation to mimic natural disturbance might revive P. correllii and/or T. texanum populations where overhanging vegetation is increasing due to lack of natural disturbance (e.g., flood pulsing, grazing, burning).

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Publication type Article
Publication Subtype Journal Article
Title Effects of shading on the rare plant species, Physostegia correllii (Lamiaceae) and Trillium texanum (Melanthiaceae)
Series title Journal of the Botanical Research Institute of Texas
DOI 10.17348/jbrit.v16.i2.1270
Volume 16
Issue 2
Year Published 2022
Language English
Publisher Botanical Research Institute of Texas
Contributing office(s) Wetland and Aquatic Research Center
Description 13 p.; 2 Data Releases
First page 591
Last page 603
Country United States
State Louisiana, Texas
County Bexar County, Cameron Parish, Chambers County, Galveston County, Gillespie County, Harris County, Kinney County, Maverick County, Montgomery County, St. Charles Parish, St. James Parish, St. Tammany Parish, Travis County, Val Verde County, Zapata County
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