Description

Seed-based revegetation is increasingly pursued in wetland restoration, but seed and seedling mortality is high and can be further limited by environmental stressors, like hydrology and salinity. The interactive effects of hydrology and salinity on native plants, especially in the presence of invasive plants, are less clear. In greenhouse and mesocosm experiments, we tested different hydrologic and salinity conditions on the growth of native seed mixes and Phragmites australis, a widespread wetland invader in North America. The greenhouse experiment tested two mixes (forb mix, graminoid mix), while mixes in the mesocosm experiment combined forbs and graminoids chosen for broad and diverging environmental tolerances. In both experiments, reduced water negatively affected native plants and P. australis, while increased salinities reduced native plant growth but had minimal impacts on P. australis. In the greenhouse experiment, forbs greatly reduced P. australis growth only under benign conditions, but still maintained growth under increasing abiotic stress despite the presence of P. australis. In the mesocosm experiment, native plants reduced P. australis growth across all conditions, indicating that mixes chosen for broad environmental tolerances can sufficiently reduce invasive growth even when negatively affected by abiotic stressors. Our results demonstrate the varying drivers of invasion resistance; sometimes environmental conditions and species' tolerances limit invasives, and other times the composition and competitive potential of the native community is more important. These results also inform wetland restoration practices i.e., choosing species for revegetation mixes with broad environmental tolerances and, when possible, manipulating wetland environmental conditions to reduce invader performance.

Document Type

Dataset

DCMI Type

Dataset

File Format

.zip

Publication Date

7-10-2024

Funder

EPA

Utah State University

Utah Agricultural Experiment Station

Publisher

Utah State University

Award Number

EPA 95810500 Utah State University A07339-1054 Utah Agricultural Experiment Station UAES 9802

Methodology

There are two experiments that contributed to this manuscript: A greenhouse experiment and a mesocosm experiment. Files are appropriately labeled beginning with "Greenhouse_" or "Mesocosm_" to denote the difference.

The greenhouse experiment investigated the effects of salinity (3 levels), water condition (2 levels), seed mix (9-species forb mix, 9-species graminoid mix), and phragmites australis presence (with, without, and a phragmites australis-only control) on native and phragmites australis ("invasive") cover and biomass. This experiment occurred March 22, 2023 - May 3, 2023.

The mesocosm experiment investigated the effects of salinity (2 levels), water condition (2 levels), seed mix (mix 1 = golden dock mix, mix 2 = sunflower mix), and phragmites australis presence (with, without, and a phragmites australis-only control) on native and phragmites australis ("invasive") cover and biomass. This experiment occurred June 7, 2023 - July 25, 2023.

Raw Data for both experiments includes weekly percent cover monitoring, an end of experiment biomass harvest, and soil salinity data.

We use 4-letter plant codes (First two letters of genus, first two letters of species) as shorthand for species names. Species names are described in the seed mix tables of the manuscript: Table 1 for the greenhouse experiment and table 2 for the mesocosm experiment.

GH is sometimes used as shorthand for the greenhouse experiment; Meso is sometimes used as shorthand for the mesocosm experiment.

We first processed raw data (.csv files) in .r scripts titled "Code_Data_Wrangle_", and then we proceeded to model analyses in files titled "Code_Model_". Analyses were performed separately for native and Phragmites australis ("invasive") models and were further separated by percent cover and biomass data.

'Function_round' is a function I created to round p values, means, and chi squared vals to the same decimal point for each table.

All data and statistical methods are described in detail in the Manuscript methods section and within the appendix 1 files.

Scientfic Names

Phragmites australis

Start Date

3-22-2023

End Date

7-25-2023

Language

eng

Code Lists

see README

Disciplines

Water Resource Management

License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Checksum

a7da261de55c04f7e79e1e29bfbd20f4

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Additional Files

README.txt (2 kB)

Function_round.R (1 kB)

Greenhouse_Biomass.csv (6 kB)

Greenhouse_Code_Data_Wrangle_Biomass.R (10 kB)

Greenhouse_Code_Data_Wrangle_Percent_Cover.R (6 kB)

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