Data from: Effort required for sustained management of non-native shrubs drops dramatically over time in a deciduous forest

Non-native plants are a major obstacle in the restoration and management
of eastern North American forests. Non-native species, particularly woody
shrubs, can be difficult to remove and extremely persistent, thus
consuming much of the time and resources available to managers. Continued,
annual control effort is needed to keep non-native abundances low.
However, how that effort will vary over time is not well documented. We
conducted a landscape scale experiment in which we managed non-native
shrubs over five years, modeling person-hours dedicated to removing
non-native shrubs as a function of initial (pre-management) non-native
shrub abundance through time. Management reduced (but did not eliminate)
non-native shrubs within the forest, and time spent controlling these
shrubs dropped following the first year of management. Control efforts
were strongly associated with the initial invasion level of the site in
the first two years of management, but unrelated to initial invasion
levels thereafter. Practical implication. Our results indicate that yearly
control of non-native shrubs can maintain these undesired species at low
abundances and further, that the time required for management decreases
markedly after the first year. More heavily invaded forests can be
expected to take more time to manage, but only over the first two years of
management, after which management efforts are no longer contingent on
pre-management invasion levels. These results are encouraging for forest
managers who seek to control non-native shrubs within forested systems.