————————————————————————————
INTRODUCTION
————————————————————————————

“Interspecific interactions between dune grasses: landscape formation by sand couch negatively affects marram grass’ establishment”
Carlijn Lammers, Valérie Reijers, Tjisse van der Heide 

Version: 12-02-2024

 This readme file describes the data accompanying the above manuscript. For any further queries please contact: 
carlijn.lammers@nioz.nl

————————————————————————————
CONTENT
————————————————————————————
Data files contain header descriptions to explain variables. 

Data files of a field experiment conducted on the Dutch Wadden Island Schiermonnikoog between April 2021 and October 2022. 

- Datafile “data_monitoring_all”, file containing field data from all monitoring moments (April 2021, October 2021, April 2022 & October 2022), including marram grass performance (length, shoot number, survival), planting (i.e., bare or within sand couch) and RTK-gps measures. 

- Datafile “data_SEM”, file containing summarised data (based on data_monitoring_all), including final marram grass survival and landscape features (i.e., elevation, distance from North Sea & elevation change) used in the structural equation models (See Rscript; survival_SEM). 

- Rscript “survival_SEM”, script with the used structural equation models (including model testing optimum of elevation change data).