Control of yellow star thistle

Yellow star thistle (Centaurea Solstitialis) is an invasive member of the Asteraceae family and has been taking over large portions of grasslands in California.

Tagavilla et al 2019 (a & b): Yellow star thistle is known to grow well in areas of full sunlight; and since south facing slopes receive more solar radiation than north facing slopes, we hypothesized that there would be higher densities of yellow star thistle on south facing slopes. To determine the spatial distribution of yellow star thistle on north and south facing slopes, we investigated an area at the Fairfield Osborn Preserve by taking GPS coordinates along north-south transects, and categorized each immediate area with a level of high, medium, low, or no density. Our data provides evidence of yellow star thistle growth patterns and could be used as a tool for invasive species management.

Elias 2019: We examine current extent and density of yellow star thistle patches, and propose treatments based on recommended best practices and Preserve Manager observations.

Project Results

Title	Format	Download	Students
"Spatial Distribution of Yellow Star Thistle at Fairfield Osborn Preserve"	presentation	Tagavilla et al 2019a Tagavilla et al 2019a	Tori Abercrombie, Natalie Gonzalez, Kaila Tagavilla, Kelsey Vella
"Spatial Distribution of Yellow Star Thistle as It Varies with Slope Aspect at Fairfield Osborn Preserve"	poster	Tagavilla et al 2019b Tagavilla et al 2019b	Toriann Abercrombie, Natalie Gonzalez, Kaila Tagavilla, Kelsey Vella
"Yellow Star Thistle (Centaurea solstitialis) Treatment at SSU's Fairfield Osborn Preserve"	poster	E-mail decourse@sonoma.edu	Samantha Elias