Homesick plants - a study on Plant-soil feedback in home and foreign soil following a latitudinal sampling gradient from Morocco to Svalbard

Abstract

Plant-soil feedbacks receive increasing attention as impactors of plant performance and drivers of plant community composition. How plant-soil feedbacks act in introduction events regarding both native and foreign species is a topic requiring more research. In this aspect, two particular theories are of interest, Home-field advantage, and Enemy-release. The former predicts that plants perform best in their native range due to positive Plant-soil feedbacks with beneficial soil biota. The latter predicts that plants will have increased performance in novel habitats, as they escape from species-specific soil-borne pathogens. While both these phenomena might be at play in introduction events, the unanswered question remains on their relative importance for predicting net plant-soil feedbacks. “Are plant-soil feedbacks more positive in native or foreign soils?” This is an indoor experimental study using minimally treated soils of six alpine grassland sites in Europe and Northern Africa, and seeds from four of those sites. Seedlings were planted in native and foreign soil and growth was compared. Climate was also manipulated, simulating Arctic and Temperate alpine grassland climates regarding temperature and photoperiod. The results reveal that home-site advantage overshadows impacts by other drivers, in the sense that plants benefitting from home soil showed stronger growth trends than plants benefitting from foreign soil. Moreover, plants perform best in climates resembling their native climate. This study concludes that plant-soil feedbacks and climate may limit establishment of populations outside their native ranges, and that plant-soil feedbacks might be controlled more by positive interactions than what earlier studies have concluded.