DOI: 10.5061/dryad.gxd2547z3
title: Salt marsh plant community development in a metacommunity experiment in the Wadden Sea

description: Shallow tidal coasts are characterized by shifting tidal flats and
 emerging or eroding islands above the high tide line. Salt marsh
 vegetation colonizing new habitats distant from existing marshes are an
 ideal model to investigate metacommunity theory. We installed a set of 12
 experimental salt marsh islands made from metal cages on a tidal flat in
 the German Wadden Sea to study the assembly of salt marsh communities in a
 metacommunity context. Experimental plots at the same elevation were
 established within the adjacent salt marsh on the island of Spiekeroog.
 For both experimental islands and salt marsh enclosed plots, the same
 three elevational levels were realized while creating bare patches open
 for colonization and vegetated patches with a defined transplanted
 community. We followed the plant community assembly from the initial setup
 in September 2014 until August 2023, when the experimental setup was
 dismantled. The dataset includes vegetation data surveyed for two squares
 of 1 x 1 m within the 2 x 2 m experimental plots that were randomly
 assigned at the start of the experiment for permanent non-destructive
 surveys. Plant species presence/absence was recorded for each 10 x 10 cm
 area within 0.9 x 0.9 m quadrants placed at the center of the plot. Our
 data highlights spatially and temporally explicit metacommunity dynamics
 that should be considered in salt marsh plant community assembly and
 disassembly. Details of the experimental setup are published in Balke et
 al. 2017.
description: # Salt marsh plant community development in a metacommunity experiment in
 the Wadden Sea Authors: Kertu Lõhmus, Angelika Hansel, Thorsten Balke,
 Michael Kleyer Kertu Lõhmus Institute of Biology and Environmental
 Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg 26129,
 Germany. [kertu.lohmus@uol.de](mailto:kertu.lohmus@uol.de)
 ORCID:0000-0003-0470-6521 Angelika Hansel Institute of Biology and
 Environmental Sciences, Carl von Ossietzky Universität Oldenburg,
 Oldenburg 26129, Germany.
 [angelika.hansel@uol.de](mailto:angelika.hansel@uol.de) Thorsten Balke
 Institute of Biology and Environmental Sciences, Carl von Ossietzky
 Universität Oldenburg, Oldenburg 26129, Germany.
 [thorsten.balke@uol.de](mailto:thorsten.balke@uol.de)
 ORCID:0000-0001-7733-5069 Michael Kleyer Institute of Biology and
 Environmental Sciences, Carl von Ossietzky Universität Oldenburg,
 Oldenburg 26129, Germany.
 [michael.kleyer@uol.de](mailto:michael.kleyer@uol.de)
 ORCID:0000-0002-0824-2974 These data were collected as part of the BEFmate
 project (2014-2018): Biodiversity - Ecosystem Functioning across marine
 and terrestrial ecosystems funded by the Ministry of Science and Culture
 of Lower Saxony, Germany under project number ZN2930 and DynaCom project
 (2019_2023): Spatial community ecology in highly dynamic landscapes: from
 island biogeography to metaecosystems funded by German Research Foundation
 under F0R 2716 ### Date of data collection Yearly from 2014 to 2024. ###
 Geographic location of data collection Salt marshes on the back-barrier
 island Spiekeroog, Germany. Coordinates provided in the file:
 DynaCom_coordinates.csv ### File list DynaCom_coordinates.csv
 DynaCom_saltmarsh_vegetation_frequency_2014_2023.csv
 DynaCom_saltmarsh_vegetation_survey_2014_2023.csv ### File descriptions
 #### DynaCom\_coordinates.csv This file provides coordinates for center of
 each 2 x 2 m sampling plot. **Variables** **PlotID**: uniqe ID for each 2
 x 2 m sampling plot combining the type of plot (either i - experimental
 island, s - salt marsh experimental plot or r - salt marsh control plot);
 elevation zone (either p - pioneer zone, l - lower salt marsh or u - upper
 salt marsh elevation); and plot number from 1 to 12 for experimental plots
 (odd numbers refering to transplanted treatment plots and even numbers to
 initally bare treatment plots) or 1 to 6 for salt marsh control plots.
 **Latitude**: WGS 84 Latitude values **Longitude**: WGS 84 Longitude
 values **UTM_Zone_32N_Easting_X**: UTM Zone 32N Easting values in m
 **UTM_Zone_32N_Northing_Y**: UTM Zone 32N Northing values in m
 **Elevation**: Orthometric Height as m above NHN standard elevation zero
 #### DynaCom\_saltmarsh\_vegetation\_frequency\_2014\_2023.csv This file
 provides plant species frequency values per plot calculated based on two
 0.9 x 0.9 m subplots (raw values are uploaded:
 DynaCom_saltmarsh_vegetation_survey_2014_2023.csv). Both these subplots
 were sampled using a counting frame with 81 10 x 10 cm cells (9 x 9
 cells). Values range from 0 to 100% based on how many of the 10 x 10 cm
 cells the species was rooted in (100 is equal to 162 cells (2x9x9)). Plots
 were sampled from 2014 to 2023. **Variables** **MeasurementID**: Unique ID
 combining sampling year and plotID **Year**: Sampling year (from 2014 to
 2023) **Type**: Refers to either i - experimental island, s - salt marsh
 enclosed experimental plot, or r - natural salt marsh control **Zone**:
 Elevational zone, either pio - pioneer zone, low - lower salt marsh or upp
 - upper salt marsh zone **Plot_number**: Plot number from 1 to 12 for
 experimental plots (odd numbers referring to transplanted treatment plots
 and even numbers to initially bare treatment plots) or 1 to 6 for salt
 marsh control plots. **PlotID**: Uniqe ID for each 2 x 2 m sampling plot
 combining the type of plot (either i - experimental island, s - salt marsh
 experimental plot or r - salt marsh control plot); elevation zone (either
 p - pioneer zone, l - lower salt marsh or u - upper salt marsh elevation);
 and plot number from 1 to 12 for experimental plots (odd numbers refering
 to transplanted treatment plots and even numbers to initally bare
 treatment plots) or 1 to 6 for salt marsh control plots. **Treatment**:
 type of treatment applied, either tranplant = plots were cleared of
 vegetation up to 30 cm depth and tranplanted with sods from nearby lower
 salt marsh, bare = plots were cleared of vegetation up to 30 cm depth and
 filled with sediment from the mudflats, control = plots were only marked
 and left as natural salt marsh reference. The following columns give the
 frequency per plant species. All species names follow World Flora Online
 accepted names as listed in April 2025. Agrostis_stolonifera
 Armeria_maritima Artemisia_maritima Atriplex_littoralis
 Atriplex_portulacoides Atriplex_prostrata Cochlearia_anglica
 Elymus_athericus Festuca_rubra Limonium_vulgare Lysimachia_maritima
 Plantago_maritima Puccinellia_maritima Salicornia_europaea
 Spergularia_media Sporobolus_anglicus Suaeda_maritima Triglochin_maritima
 Tripolium_pannonicum ####
 DynaCom\_saltmarsh\_vegetation\_survey\_2014\_2023.csv This file provides
 plant species presence/absence recordings per 10 x 10 cm cell of a 0.9 x
 0.9 m counting frame. Species was recorded as present if it was rooted in
 the cell. Plots were sampled from 2014 to 2023. **Variables**
 **MeasurementID**: Unique ID combining sampling year, plotID, subplot
 number, and counting frame cell ID **Year**: Sampling year (from 2014 to
 2023) **Type**: Refers to either i - experimental island, s - salt marsh
 enclosed experimental plot, or r - natural salt marsh control **Zone**:
 Elevational zone, either pio - pioneer zone, low - lower salt marsh or upp
 - upper salt marsh zone **Plot_number**: Plot number from 1 to 12 for
 experimental plots (odd numbers referring to transplanted treatment plots
 and even numbers to initially bare treatment plots) or 1 to 6 for salt
 marsh control plots. **Subplot_number**: nuber of the 0.9 x 0.9 m suplot
 either 1 or 2 **FrameID**: Counting frame cells were counted as letters A
 - I from West to East on the salt marsh plots and East to West on the
 experimental island plots and 1 - 9 form North to South on the salt marsh
 plots and South to North on the experimental island plots. FrameID
 combines the letter and number to a cell ID **PlotID**: Uniqe ID for each
 2 x 2 m sampling plot combining the type of plot (either i - experimental
 island, s - salt marsh experimental plot or r - salt marsh control plot);
 elevation zone (either p - pioneer zone, l - lower salt marsh or u - upper
 salt marsh elevation); and plot number from 1 to 12 for experimental plots
 (odd numbers refering to transplanted treatment plots and even numbers to
 initally bare treatment plots) or 1 to 6 for salt marsh control plots.
 **Treatment**: type of treatment applied, either tranplant = plots were
 cleared of vegetation up to 30 cm depth and tranplanted with sods from
 nearby lower salt marsh, bare = plots were cleared of vegetation up to 30
 cm depth and filled with sediment from the mudflats, control = plots were
 only marked and left as natural salt marsh reference. The following
 columns give the frequency per plant species. All species names follow
 World Flora Online accepted names as listed in April 2025.
 Agrostis_stolonifera Armeria_maritima Artemisia_maritima
 Atriplex_littoralis Atriplex_portulacoides Atriplex_prostrata
 Cochlearia_anglica Elymus_athericus Festuca_rubra Limonium_vulgare
 Lysimachia_maritima Plantago_maritima Puccinellia_maritima
 Salicornia_europaea Spergularia_media Sporobolus_anglicus Suaeda_maritima
 Triglochin_maritima Tripolium_pannonicum