DOI: 10.5061/dryad.5hqbzkhfh
title: Genetic diversity matters for restoration of a threatened saltmarsh plant in harsh environments

description: While genetic diversity is theorised to increase the restoration success
 of degraded plant populations, previous studies examining its impacts on
 restoration outcomes have yielded mixed results. We hypothesise that the
 importance of genetic diversity for the performance of plants targeted for
 restoration increases with environmental stress and varies with specific
 plant traits related to different plant successive life stages. To test
 this, we conducted a fully factorial common garden experiment, crossing
 salinity and genetic diversity under low- and high-nitrogen conditions on
 the growth and reproduction of Scirpus mariqueter, a threatened endemic
 saltmarsh plant in the Yangtze Estuary. The impacts of genetic diversity
 varied across stress gradients and metrics. Under high stress (high
 salinity, low nutrients), greater diversity enhanced reproductive traits
 such as clonal growth and seed production, but not under low stress. Plant
 growth traits showed no diversity effects regardless of stress. Synthesis.
 Our results highlight the importance of considering intraspecific genetic
 diversity in ecological restoration and help explain the context-dependent
 effects of diversity.
description: # Genetic diversity matters for restoration of a threatened salt marsh
 plant in harsh environments
 [https://doi.org/10.5061/dryad.5hqbzkhfh](https://doi.org/10.5061/dryad.5hqbzkhfh) **Context and Hypothesis** The study investigates the role of genetic diversity in the restoration of the salt marsh plant Scirpus mariqueter under varying environmental stress conditions.The hypothesis posits that genetic diversity's importance for plant performance increases with environmental stress and varies with plant traits across different life stages. **Experimental Design** A fully factorial common garden experiment was conducted. Variables: Salinity (low: ~4‰, high: ~18‰), Nitrogen (low: 0.70-1.10‰, high: +0.72 g), Genetic Diversity (1, 4, or 8 genotypes). Plants were grown in four cement ponds with different salinity and nutrient levels. **Procedures** Collection: 74 genetically diverse ramets from Chongming Dongtan wetland. Propagation: Asexual propagation to generate sufficient materials. Genotype Identification: DNA extraction and PCR amplification using 12 polymorphic DNA microsatellites. Planting: 21 selected genotypes planted in various combinations in 252 pots. Stress Simulation: Manipulation of salinity and nutrient levels in the ponds. Measurements: Plant survivorship, maximum height, aboveground biomass, density, and seed production. **Results** **Survivorship:** No significant variation with genetic diversity or salinity under either nitrogen condition. Growth Response: Maximum height and aboveground biomass were significantly lower in high-salinity conditions but unaffected by genetic diversity. **Reproductive Response:** Reproductive traits (density and seed production) were more sensitive to stress. High genetic diversity significantly enhanced clonal growth and seed production under high-stress conditions (high salinity and low nitrogen). No significant diversity effects under less stressful conditions. **Conclusions** Genetic diversity's benefits are more pronounced under high environmental stress, particularly for reproductive traits rather than growth traits. Enhanced genetic diversity improved reproductive performance in high-stress environments, indicating the importance of considering genetic diversity in restoration strategies. The dataset supports the hypothesis that genetic diversity is crucial for restoration success under stressful conditions and highlights the varying impact of genetic diversity across different plant traits and life stages. ## Description of the data and file structure The dataset "data 1.csv" and its associated metadata "metadata.txt" provide detailed information on a common garden experiment designed to study the impact of genetic diversity and environmental stressors on the salt marsh plant Scirpus mariqueter. The dataset includes various metrics related to plant performance under different experimental conditions. **File Structure** **1. data 1.csv** This is the primary data file containing experimental results. Columns in the CSV file represent different variables and measurements collected during the experiment. **2. metadata.txt** Provides a detailed description of each column in the CSV file. Explains the experimental setup and the context of the data collected. **Key Variables and Metrics** **1.pond:** Indicates one of the four cement ponds used in the common garden experiment. Values: 1, 2, 3, 4. **2.pot:** Unique identifier for each pot within the ponds. Each pot contains plants subjected to the experimental conditions. **3.richness:** Represents genotype richness, which is the number of different genotypes in each pot. Values: 1 (monoculture), 4, 8 (multi-genotype mixtures). **4.nitrogen_added (g):** The amount of nitrogen added to each pot. Describes the nutrient level: low nitrogen (0) or high nitrogen (+0.72 g). **5.salinity:** The concentration of sea salt in each pond. Values: ~4‰ (low salinity), ~18‰ (high salinity). **6.stressful_conditions:** Describes the stress level in each pond based on salinity and nitrogen levels. Conditions: High stress (high salinity, low nitrogen), moderate stress, low stress (low salinity, high nitrogen). **7.survivorship (%):** The survival rate of ramets (individual plant units) in each pot. Measured as the proportion of ramets that survived. **8.maximum_high (cm):** The maximum height of ramets in each pot. Reflects plant growth performance. **9.above_all (g):** Aboveground biomass of plants in each pot. Total biomass of stems and leaves, indicative of overall plant health and productivity. **10.density:** The number of ramets in each pot. Indicates clonal growth and reproduction capacity. **11.n_sur:** The seed presence or absence in each pot. Measures reproductive success and potential for future propagation. **Relationships Between Data Files** The metadata.txt file describes the contents and structure of data 1.csv, providing context and definitions for each variable. Each row in data 1.csv represents a single pot's experimental results, detailing the conditions applied and the observed plant performance metrics. **Missing Data Codes and Abbreviations** Missing data are typically denoted as "NA" in the CSV file. Common abbreviations used in the data: GD: Genetic Diversity SA: Salinity NA: Nitrogen Addition **Usage Notes** **Data Analysis:** Researchers can use this dataset to analyze the effects of genetic diversity and environmental stress on plant performance. Statistical models (e.g., linear mixed-effects models) can be applied to explore relationships between genetic diversity, environmental conditions, and plant traits. **Restoration Planning:**  The findings can inform strategies for restoring salt marshes by highlighting the importance of genetic diversity in stressful environments. **Ecological Studies:** The dataset provides a valuable resource for studying intraspecific variation and its implications for ecosystem resilience and function. This dataset, with its comprehensive experimental design and detailed measurements, is crucial for understanding the dynamics of salt marsh restoration and the role of genetic diversity in ecological resilience. ## Sharing/Access information N/A