Impacts of invasive alien N-2-fixing woody species and how they can persist as soil
legacy effects after invasive species control are well appreciated, but how soil legacy
effects can present barriers to restoration is poorly understood. Finding better ways
to deal with these barriers to restoration is essential to improving restoration outcomes.
In this study, we review 440 studies to identify barriers to restoration and potential
management actions for the barriers to restoration, and provide practical application
examples of the management actions. Our findings suggest that altered soil microbial
communities, depleted native soil seed banks, elevated N status, secondary invasion
and weedy native species dominance, and reinvasion are potential barriers to restoration.
Furthermore, carbon addition, litter removal, soil microbial treatments, establishing
species adapted to low N levels, prescribed burning, classical biological control,
grazing, mowing, herbicide or graminicide application, manual weeding, soil N management,
soil solarization, weed mats, native species reintroduction, and nurse plants are
potential management actions for these barriers to restoration. However, there is
little evidence suggesting that several of these barriers to restoration hinder improved
restoration outcomes and this could be due to little research on them. More research
is needed to assess their relative importance in hindering improved restoration outcomes.
Management actions are rarely applied in combination, despite that they often address
distinct barriers to restoration. Management actions should be combined into an integrated
management effort to improve restoration outcomes.