Grassroots Ecology: Plant–microbe–soil Interactions as Drivers of Plant Community Structure and Dynamics

Abstract

Abstract. A growing body of research on plant-microbe interactions in soil is contributing to the development of a new, microbially based perspective on plant community ecology. Soil-dwelling microorganisms are diverse, and interactions with plants vary with respect to specificity, environmental heterogeneity, and fitness impact. Two microbial processes that may exert key influences on plant community structure and dynamics are microbial mediation of niche differentiation in resource use and feedback dynamics between the plant and soil community. The niche differentiation hypothesis is based on observations that soil nutrients occur in different chemical forms, that different enzymes are required for plant access to these nutrients, and that soil microorganisms are a major source of these enzymes. We predict that plant nutrient partitioning arises from differential associations of plant species with microbes able to access different nutrient pools. Feedback dynamics result from changes in the soil community generated by the specificity of response in plantmicrobe interactions. We suggest that positive feedback between plants and soil microbes plays a central role in early successional communities, while negative feedback contributes both to species replacements and to diversification in later successional communities. We further suggest that plant-microbe interactions in the soil are an important organizing force for large-scale spatial gradients in species richness. The relative balance of positive feedback (a homogenizing force) and negative feedback (a diversifying force) may contribute to observed latitudinal (and altitudinal) diversity patterns. Empirical tests of these ideas are needed, but a microbially based perspective for plant ecology promises to contribute to our understanding of long-standing issues in ecology, and to reveal new areas of future research.

Influence of fire history and soil properties on plant species richness and functional diversity in a neotropical savanna

“…In addition, fire removes pre-existing biomass, creating open areas in which competition decreases (Hoffman 2002), and can increase facilitation among plants (Franks & Peterson 2003). At low levels of soil nitrogen, only a few adapted plant species with similar traits (e.g., several plant species with symbiotic bacteria in their root systems) can establish themselves (Reynolds et al 2003;Fornara & Tilman 2008). In this sense, patches with higher soil nitrogen content seem to reduce niche limitation effects, and the presence of nitrogen-fixing species increases the likelihood of facilitation (Fornara & Tilman 2008), resulting in an increase not only in species richness but also in the FDis of woody species.…”

Succession of plant and soil microbial communities with restoration of abandoned land in the Loess Plateau, China

“…The target indigenous species of plants with a managed community of microbial symbionts were applied in the recovery of desertified ecosystems, which is a successful biotechnological tool (Requena et al 2001). Positive and negative feedbacks between plants and soil microbes play central roles in early and later successional communities (Reynolds et al 2003). Present conclusions were drawn from individual soil bacteria, archaea, and fungi, which were not treated as integral despite the fact that three kingdoms of microbes are known to interact with one another and jointly serve ecological functions.…”

Disease in Natural Plant Populations, Communities, and Ecosystems: Insights into Ecological and Evolutionary Processes

“…A focus of future work is likely to be twofold. First, there is a need to dissect the black box of the soil community to understand which organisms and combinations contribute to ecologically relevant effects (106). Second, more detailed studies of patterns of plant density dependence, host specificity of pathogens, and the entire plant life cycle are needed to fully explore these hypotheses (51).…”