Invasive grasses consistently create similar plant–soil feedback types in soils collected from geographically distant locations

Abstract

Invasive PSF is limited by soil type. Most, but not all, plant species exhibit negative plant soil feedback (PSF), wherein plants perform poorly in soils formerly occupied (conditioned) by conspecifics. This dynamic has led to the Plant-Soil Feedback Hypothesis of Invasion which posits that plant species have greater invasive potential when they create PSFs that benefit conspecifics over heterospecifics (consequently creating ‘invasive’ PSFs). This hypothesis was tested using four invasive plant species and three soils collected from distinct areas within and outside each species currently-invaded range. If plant-soil feedback contributes to invasive potential, species should create invasive PSFs and the PSF should be consistent among soils from the currently-invaded range. We determine PSF by examining conspecific and heterospecific performance in soil conditioned by each invasive species. Results partially support the Plant-Soil Feedback Hypothesis of Invasion. Taeniatherum caput-medusae generated invasive PSFs in soils from all three origins, and Agropyron cristatum generated invasive PSFs in two of the three soil origins. Centaurea solstitialis did not create invasive PSFs in the soil from its invasive range, but did exhibit an invasive PSF from a soil just beyond its invasion edge. Poa pratensis did not demonstrate any PSF effect.