Sedimentation, sediment grain size, vegetation composition and vegetation characteristics on a salt marsh in nature reserve the Slufter (Wadden island Texel, the Netherlands)

 B. Martina Baaij, Jantsje M. van Loon-Steensma, Juul Limpens


The data is described in the following publication:
Baaij, B.M., Kooijman, J., Limpens, J., Marijnissen, R.J.C., van Loon-Steensma, J.M. Monitoring Impact of Salt-Marsh Vegetation Characteristics on Sedimentation: an Outlook for Nature-Based Flood Protection. Wetlands 41, 76 (2021). https://doi.org/10.1007/s13157-021-01467-w


Aim: investigate effect of vegetation presence, vegetation type and vegetation characteristics on sedimentation and sediment grain size.

Study design field experiment: 56 plots (2.5 x 2.5 m) were established on a salt marsh in nature reserve the Slufter on de Wadden island of Texel, the Netherlands. Plots were made in four vegetation types: vegetation dominated by either Salicornia species (Salicornia type), Spartina anglica (Spartina type), Atriplex portulacoides (Atriplex type) or Limonium vulgare (Limonium type). Pairs of plots were made near a creek within the same vegetation type. One of the plots within a pair was established at a short distance to the creek, while the other plot was established at a longer distance to the creek. Plots were arranged in seven experimental blocks, each block consisting of one pair of plots per vegetation type. In each plot, two subplots (50 x 50 cm) were made 1 m apart and with the same distance to the creek. One subplot consisted of intact vegetation, whereas the vegetation in the other subplot was clipped to the soil surface. The experiment lasted for seven weeks between August and October in 2018.

Measurements:
- Vegetation composition
- Vegetation characteristics (total cover, vegetation height, stem height, stem diameter, branching level, stem density and biomass)
- Sedimentation per subplot
- Sediment grain size

For more details on the background and methods, we refer to the publication (Baaij et al. 2021).


Data files
The file ‘Data overview’ gives an overview of the data analyzed in the manuscript.
- Number (1-56; unique number for each of the 56 plots)
- Code (unique code for each of the 56 plots present in each file)
- Study design
o Block (1-7)
o Salt marsh zone (pioneer, low salt marsh)
o Vegetation type (Salicornia, Spartina, Limonium and Atriplex type)
o Distance to the creek (short, long distance to the creek)
- Location (and elevation of the subplots vegetation removed, vegetation present)
o Latitude vegetation removed
o Longitude vegetation removed
o Elevation vegetation removed (m +NAP) (Dutch ordnance level, close to mean sea level)
o Latitude vegetation present
o Longitude vegetation present
o Elevation vegetation present (m +NAP)
o Elevation of plot (m) (average of the two subplots)
o Distance to the creek (m)
- Plant communities (determined with SynBioSys based on plant species and cover)
o Syntaxon code
o Scientific name
- Vegetation characteristics
o Total cover (%)
o Vegetation height (cm)
o Stem height (cm)
o Stem diameter (mm)
o Branching level
o Stem density (#/m²)
o Biomass (g/m²)
- Sedimentation (measured with four sediment traps per subplots over a period of two weeks; Block 1 18-09-2018/05-10-2018; Block 2 18-09-2018/02-10-2018; Block 3,4 19-09-2018/03-10-2018; Block 5 24-09-2018/05-10-2018; Block 6,7 20-09-2018/04-10-2018) 
o Sedimentation vegetation removed (g/m²)
o Sedimentation vegetation present (g/m²)
- Sediment grain size (of the upper 1 cm of the soil)
o Median grain size (µm)

The file ‘Additional data vegetation composition and characteristics’ gives raw and edited data on vegetation composition and vegetation characteristics. The plant species and cover per plot is presented in the sheet ‘Vegetation composition’. The sheet ‘Vegetation char. per plant’ gives the stem height, stem diameter and branching level of five individuals per species in a plot and the stem density and biomass per species for different areas. The final three sheets show how the values per plot of the vegetation characteristics total cover, stem height, stem diameter, branching level, stem density and biomass are calculated based on the values per species.

The file ‘Additional data grain size distribution’ gives the complete output including summary values of the grain size distribution analysis using a Sympatec HELOS/KR Laser Diffraction Machine.