Differences in soil ecology and fungal symbionts in a Halogeton invasion zone at the Desert Experimental Range, Utah

We studied a cold desert site in western Utah where a monoculture of Halogeton glomeratus, an exotic annual chenopod, has been expanding into a native winterfat (Krascheninnikovia lanata) dominated community since 1969. We measured plant and soil nutrients, soil microbiology, and fungal symbionts from the native area, the halogenton monoculture, and the narrow (approximately 5 m) ecotone between them. A PCA of nutrient levels showed clear separation between soils collected from the native and exotic areas as well as between halogeton tissues collected from the monoculture and the ecotone. The diversity of soil bacteria was highest in the exotic, intermediate in the ecotone, and lowest in the native community. Fungal endophytes and soil populations of fungi also differed according to whether the plant was collected in a parental (native or exotic) zone or the ecotone. Our results offer evidence that the invasion of halogeton alters various aspects of soil chemistry and soil ecology at this site.