Performance of seven species in clustered versus uniform plantings in a large-scale high marsh restoration project

Large-scale restoration projects are an exciting and largely untapped opportunity to use an experimental approach to inform ecosystem management and test ecological theory. This paper takes advantage of a $10M marsh restoration project with long-term monitoring to test the relative importance of facilitation and competition across stress gradients. Clustered plantings have the potential to outperform widely spaced ones, if plants alter conditions in ways that decrease stress for close neighbors. Here, we test whether intraspecific facilitation improves restoration outcomes using a suite of seven high marsh species native to central California salt marshes. We also applied a biochar treatment to test whether soil amendment boosts restoration success. We compared performance of clustered and uniform plantings across the high marsh elevation gradient for three years. There was a strong effect of elevation on plant performance and clear signs of plant stress related to soil conditions. Clus..., This dataset contains:

Early survival data for species planted in clustered versus uniform treatments across an elevation transect, including:

Distichlis spicata
Extriplex californica
Frankenia salina
Jaumea carnosa
Spergularia macrotheca

Growth and later survival data collected from marked plants at designated \"High\" and \"Low\" elevation locations

All species above, plus Limonium californicum and Triglochin concinna at High elevation only

Transplant and exotic cover data collected on point intercept transects across elevation in 2019, 2020, and 2021

See Methods and Appendix S1 for further details on data collection methods and statistical analyses.
The attached archive includes a read-me file that details the content of each .csv in the data set., , # Performance of seven species in clustered versus uniform plantings in a large-scale high marsh restoration project

[https://doi.org/10.5061/dryad.kwh70rzd9](https://doi.org/10.5061/dryad.kwh70rzd9)

## Overview of the experimental design

In the fall of 2018 we established six blocks at the restored marsh in the high marsh elevation band (~1.95 - 2.20 m North American Vertical Datum of 1988). Each block was subdivided into 10 columns, with 2 columns allocated to each primary species (Distichlis spicata, Extriplex californica, Frankenia salina, Jaumea carnosa, and Spergularia macrotheca); one column in each pair was planted in the Uniform treatment and one in the Clustered treatment (see Appendix S1: Experimental design for more details). We also planted Limonium californicum and Triglochin concinna in “wings” on either side of each block, as transplant stock allowed; wings were installed near the top of blocks because these species tend to occur at the upper edge of the high marsh in...