Data from: Intraspecific facilitation explains the persistence of Phragmites australis in modified coastal wetlands. Ecosphere.

Here, we experimentally tested how intraspecific facilitation increases the persistence of common reed (Phragmites australis) in saline environments. We crossed two stages of Phragmites communities (pioneer vs. established) with both freshwater and saline (20 psu) conditions. Our results indicated a clear shift from competition in freshwater conditions to facilitation in saline conditions. Detailed measurements of both soil and plant biogeochemical properties revealed two self-facilitative mechanisms that enabled established reed stand to persist in saline environments: (i) density-dependent rainwater infiltration lowered salinity levels in the root mat and (ii) enhanced root oxygenation decreased accumulation and intrusion of phytotoxic sulfide.

The experiment was conducted using plant material from the West-Frisian barrier island of Schiermonnikoog in the greenhouse facilities of the Radboud University during the spring of 2015. The full methodology can be found in the linked paper.

This dataset contains plant performance characteristics, plant biogeochemical and soil biogeochemical data of the experimental plots.