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Tanner Humphries (picture below) arrived from Western Washington University this past Monday to start his 2-month internship at MPG Ranch. He will help us with ongoing projects and also spearhead one of his own. Knapweed (Centaurea stoebe) invades plant communities in Montana but not in western Washington for unknown reasons. Tanner will grow MT and WA knapweed under the same conditions and compare their performance. He will also learn whether plants and soil microbial communities coevolved and if plants perform better when grown with their own soil microbial community compared with a community they have never encountered. In his spare time, he has promised to help weed our vegetable garden and spend time exploring the surroundings on a mountain bike. We look forward to 8 exciting weeks with Tanner!

Tanner Humpheries

Tanner Humphries plants

knapweed seeds for his

project on his first day on

the ranch. After the seeds

germinate, he will

transplant seedlings into

soil collected from either

MPG Ranch or western

Washington to see if plants

grow best in their “home”

soil environment. By

comparing growth of

plants from MT and WA,

we can also see if knapweed

from MT is more invasive partly

because MT plants grow

more vigorously than WA plants.

About the Author

Ylva Lekberg

Ylva graduated from the Swedish University of Agricultural Sciences with a M.Sc. in Biology and Horticulture in 1996 and a Ph.D. in Ecology from Penn State University in 2004. She received the Alumni Association Dissertation Award for her work in agroecology and subsistence farming in Sub-Saharan Africa. Post-doctoral positions at Montana State University and later at Copenhagen University as a Marie Curie Fellow allowed her to explore the role of arbuscular mycorrhiza, a root-fungus symbiosis, for geothermal plants in Yellowstone National Park and coastal grasslands in Denmark. Her research has been published in international journals such as Nature Communications, Ecology Letters, and New Phytologist.

Ylva joined MPG Ranch in 2010. Since then, she has explored how invasive plants common to western Montana, including spotted knapweed (Centaurea stoebe), leafy spurge (Euphorbia esula) and cheatgrass (Bromus tectorum), influence soil microbial community composition and function, and how this in turn may affect invasive success. A lot of her research also focuses on the AM symbiosis in terms of community ecology and physiology. A current project addresses how exchange ratios in this symbiosis may differ among co-occurring plants and depend on soil nutrient availabilities. She uses surveys, field and greenhouse experiments, and literature approaches such as meta-analyses to address questions. To learn more about research and publications from Ylva and her group, see CV below and the Soils, Plants and Invasion section.

In addition to her work at MPG Ranch, Ylva is an adjunct professor at University of Montana at the Department of Ecosystem and Conservation Sciences.