Native plants fare better against an introduced competitor with native microbes and lower nitrogen availability

Area of Science:

• Ecology
• Plant Biology
• Soil Science

Background:

• Soil environment significantly impacts plant competition dynamics.
• Understanding the roles of soil resources and microbes is crucial for native and exotic plant interactions.
• Plant community resilience to invasion may depend on soil's abiotic and biotic factors.

Purpose of the Study:

• To investigate the relative importance of soil resources and soil microbes in mediating competition between native and exotic plant species.
• To assess how nitrogen availability and native soil microbial communities affect plant performance and competitive outcomes.
• To determine the influence of intraspecific versus interspecific competition under varying soil conditions.

Main Methods:

• Greenhouse experiment comparing two native prairie plant species and one exotic species.
• Manipulated nitrogen availability (elevated vs. native levels).
• Assessed plant performance with and without a native prairie soil microbial community.

Main Results:

• Elevated nitrogen benefited the exotic species while harming or having no effect on native species.
• Native microbial communities benefited native species and negatively impacted or had no effect on the exotic species.
• Intraspecific competition was stronger for the exotic species, while interspecific competition was stronger for native species.

Conclusions:

• Soil nitrogen availability and microbial communities mediate competition between native and exotic plants.
• Native microbes do not enhance exotic plant performance; their absence exacerbates negative effects of high nitrogen on natives.
• Intact native soil microbial communities enhance resilience to invasion, while nitrogen enrichment weakens it.