DOI: 10.5061/dryad.gmsbcc2s8
title: Data for: Bed-scale impact and recovery of a commercially important intertidal seaweed

description: As the value of ecosystem-based management (EBM) approaches is
 increasingly recognized in marine ecosystems, it is critical that the
 impacts of resource harvest are assessed at various spatial scales. This
 is particularly true for habitat-forming resources, such as wild seaweeds,
 that act as foundation species by physically structuring ecosystems. The
 impacts of spatially heterogeneous harvest may change with scale and have
 different management implications based on the ecosystem process or
 organism under consideration. Ascophyllum nodosum (hereafter rockweed) is
 a canopy-forming fucoid seaweed endemic to rocky coastlines in the North
 Atlantic Ocean that has been harvested for centuries. We conducted a
 Before-After Control-Impact study of commercial rockweed harvest at 38
 sites across the coast of Maine (USA) from 2018 to 2020 in an effort to
 understand impact and one-year recovery of two rockweed bed structural
 characteristics, height and biomass, at a scale similar to a single
 harvest event. Our results indicate that rockweed harvest is spatially
 heterogeneous at the scale of the rockweed bed, and as a result, the
 effect sizes of harvest at this scale are smaller than those reported in
 previous studies that assessed smaller spatial scales. Mean rockweed
 biomass recovered to pre-harvest values after one year of recovery, but
 mean rockweed height remained lower at impacted sites. While post-harvest
 recovery was generally high in our study, sites that experienced higher
 intensities of harvest were less likely to fully recover height or biomass
 one year post-harvest. Our findings provide resource managers with a
 bed-scale perspective that can inform EBM approaches, particularly for
 population-level management of harvested resources and impacts of harvest
 on highly mobile organisms—such as birds and fish—that interact with these
 ecosystems at larger spatial scales.
description: All data were collected in the field between 2018 and 2020 in
 Maine (USA). All datasets were cleaned and organized in
 program R.
description: Datasets are .csv files and can be opened in any text editor.
 Code for analyses can be opened in program R.
description: # Data for "Bed-scale impact and recovery of a commercially important
 intertidal seaweed" # Johnston et al. 2023 # Journal of Experimental
 Marine Biology and Ecology --- This dataset contains five files that focus
 on field-collected data and data analyses of a research study assessing
 the impacts of rockweed (*Ascophyllum nodosum*) harvest on rockweed height
 and biomass. ## Description of the Data and file structure baci.csv - Raw
 field collected data for Before-After Control-Impact study. Contains date
 and location information, and values of several rockweed characteristics
 collected throughout the study. The file also includes mean values at
 different hierarchical spatial scales. baci_metadata.csv - metadata for
 baci.csv. Explains the data collected in each column. baci_delta.csv -
 site-level averages that summarizes the data in baci.csv. Includes
 absolute and percent changes in three rockweed characteristics (holdfast
 count, height, biomass) over several time period intervals.
 baci_delta_metadata.csv - metadata for baci_delta.csv. Explains the data
 collected in each column. baci_analyses_code.R - R script that executes
 main data analyses. Uses baci.csv and baci_delta.csv as input files. ##
 Sharing/access Information These datasets were not derived from another
 source, and they are not publicly accessible in other locations.