DOI: 10.5061/dryad.rbnzs7hpb
title: Data from: Effort required for sustained management of non-native shrubs drops dramatically over time in a deciduous forest

description: 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.
description: # Effort required for sustained management of non-native shrubs drops
 dramatically over time in a deciduous forest
 [https://doi.org/10.5061/dryad.rbnzs7hpb](https://doi.org/10.5061/dryad.rbnzs7hpb) ## Description of the data and file structure Nonnative shrub surveys. Non-native shrubs were surveyed annually from 2018 to 2023. Monitoring began one to two years before the onset of management, depending on whether management was initiated in 2018 or 2019, respectively. Surveys were conducted between May and July. We visually surveyed non-native shrubs in circular plots with a 4-meter radius centered on a mature tree of either A. saccharum, A. rubra, or L. tulipifera (frequently), but also Q. rubra or U. rubra (rarely). Between 11 and 65 survey plots were haphazardly established per management plot. To organize the visual surveys, we subdivided each circular survey plot in half (north – south). Within each half-circle, we surveyed the four most dominant non-native shrubs: R. multiflora, R. frangula, Lonicera spp., and Ligustrum spp., assessing the fraction of ground cover occupied by each shrub based on cover classes from the Daubenmire scale (1: ≤ 5%, 2: 6%-25%, 3: 26%-50%, 4:  51%-75%, 5: 76%-95%, 6: &gt;95%, Daubenmire 1959). Cover classes were later converted to a single percentage value based on the midpoint of the range. Each year, to quantify efforts devoted to nonnative shrub removal, we noted the crew size and hours spent on shrub removal within each management plot. These data were used to calculate person-hours spent on non-native shrub removal within each management plot within each year. ### Files and variables #### File: removal\_effort.csv **Description:**  ##### Variables * year: Calendar year of management * hours: number of person-hours devoted to shrub removal * plot: management plot where shrub removal was done #### File: shrub\_surveys.csv **Description:**  ##### Variables * Tree: The target tree where the shrub survey was conducted * Direction: Denotes the semi-circular plot (north or south) * year: The calendar year of survey * Plot_ID: The management plot where the survey was conducted * percent_shrub_cover: The total % ground cover of non-native shrubs in a particular semicircular survey plot ## Code/software Data are saved a comma delimited text. Any text editor and most software should readily read and import data.