Controlling a tree invader for coastal plant communities' restoration affected below‐ground dynamics

Abstract Controlling invasive non‐native species is one of the main challenges of ecological restoration, but little is known about what happens below‐ground when they are controlled. A better understanding of what happens below‐ground when restoring plant communities may be useful to better plan restoration. To fulfil this knowledge gap, we used coastal vegetation on sandy soils in the Brazilian Atlantic Forest (so‐called restinga ) as a model to investigate below‐ground dynamics in communities under restoration. We evaluated the effect of controlling an invasive pine tree ( Pinus elliottii ) on fine root biomass, community root length and ectomycorrhizal rate (% of ectomycorrhizae—ECMs in root tips) on resting plant communities. We collected root samples in non‐invaded and invaded areas, and areas where pine trees have been removed as a control method (hereafter managed areas). The plant community fine root biomass and fine root length density were lower in the invaded area, and similar in non‐invaded and managed areas. Effect sizes showed higher ECM rate in the invaded and non‐invaded areas, and the lowest ECM rate where P. elliottii was controlled, but no significant differences were observed among those values. By showing novel data on fine root biomass, length and ECM rate when invasive non‐native trees were controlled, our work fills a knowledge gap exploring how native plant communities respond to invasion control after 6 years of interventions. The decrease in fine roots in the invaded area, and the equivalent values in the managed and non‐invaded ones suggest that the removal of pines was sufficient for the recovery of native vegetation. Synthesis and applications . Invasive plant species can lead to changes in root structure and affect ecosystem functioning. Root dynamics play a role in the process of natural regeneration and restoration when an invasive plant is controlled, and legacy effects should be considered in planning and monitoring.