# Nitrogen-fixing plants increase soil nitrogen and neighboring plant biomass, but decrease community diversity: A meta-analysis reveals the mediating role of soil texture [https://doi.org/10.5061/dryad.4qrfj6qk1](https://doi.org/10.5061/dryad.4qrfj6qk1) ## Description of the data and file structure This data file was constructed by gathering and extracting data from published scientific papers identified using a rigorous selection process (see manuscript for details on the selection process). The papers included in this data are identified within the primary dataset here, but also in the supplementary file of the manuscript. This dataset includes original manuscript information, data extractor, geographical and ecological data, and notation of any treatments or differences in groups, along with the means and error terms for each data point extracted. This is the raw data used for this paper. The 'yi' and 'vi' terms in the dataset are the individual log response ratio (lnRR) and variation, respectively. These are the terms used in all analyses presented in the final manuscript. There are moderators included in this dataset to account for and test for heterogeneity within the response of interest. However, given the nature of this type of analysis, there are quite a few missing data points from the various moderators; these are noted with an "N/A" in the dataset. The data file is titled "Ortiz-Wolf-2024-JoE.xslx" - this data file contains two spreadsheets: 'metadata' and 'dataset'. The 'metadata' spreadsheet describes each attribute (including abbreviations and units) in 'dataset'. The 'dataset' spreadsheet contains the independent effect sizes (Log Response Ratio) for each data point and the available moderator data there were used in our meta-analyses and used to generate figures presented in our manuscript and supplemental file. ## Sharing/Access Information NA

Several recent regional studies have cast doubt on the widespread assumption that nitrogen-fixing plants (N-fixers) act as facilitators of neighboring plant communities. We conducted a meta-analysis to synthesize the effects of N-fixers on plant communities and to understand how ecological context moderates these effects. We analyzed studies that assessed paired effects of N-fixers and non-fixers on soil N, neighboring-plant (non-fixer) biomass, and plant community diversity; ecological moderators included climate, soil texture, and N-fixer growth form and invasive status. N-fixers led to higher soil N and neighboring plant biomass, but lower community diversity compared to non-fixers. The effect of N-fixers on neighboring plant biomass was strongly mediated by soil texture; N-fixer invasive status and growth form were also significant mediators of the facilitative effects of N-fixers. N-fixer effects lie on a continuum between facilitation and suppression that is moderated by intrinsic and extrinsic processes, and this analysis provides insight into how these factors moderate the effects of N-fixers. Overall, N-fixers facilitate neighbor biomass but suppress diversity, though high variation in these effects can be explained in part by ecological context.