Intraspecific Plant–Soil Feedbacks Link Ecosystem Ecology and Evolutionary Biology

Abstract

The interactions among plants, soil biotic communities, and soil are increasingly shown to be important in ecology but are underappreciated in evolutionary biology. Through genetic interactions among co-occurring taxa, plants and the biotic soil community influence the fitness and performance of each over time. At the intraspecific level, variation in plant traits leads to conditioning of soil physical and chemical properties and biotic communities which can have positive, neutral, or negative feedbacks to plants. These feedbacks can have positive fitness effects that lead to divergence of traits in plants. Building on the growing literature showing the genetic basis to plant conditioning of soils and the role of plant–soil feedback in determining plant performance and fitness, we review: (1) evolutionary theory linking plants and soils (which broadly includes soil physical and chemical properties as well as the biotic community); (2) provide examples of genetically based variation in plant–soil feedback (PSF); and (3) identify the evolutionary consequences of PSF. Together, modeling and empirical results show that intraspecific interactions among plants and soils vary across environments that can lead to geographic variation in feedback responses and evolutionary divergence. Both local adaptation and maladaptation are equally likely to occur which can drive divergence in plant traits and ecosystem function in different directions. Overall these results demonstrate that plant–soil interactions are ideal for demonstrating eco-evolutionary feedbacks which has implications for understanding a range of population, community, and ecosystem outcomes in a changing world.