DOI: 10.6086/d1vq36
title: Data for: Prescribed versus wildfire impacts on exotic plants and soil microbes in California grasslands

description: Prescribed burns are often used as a management tool to decrease exotic
 plant cover and increase native plant cover in grasslands. These changes
 may also be mediated by fire impacts on soil microbial communities, which
 drive plant productivity and function. Yet, the ecological effects of
 prescribed burns compared to wildfires on either plant or soil microbial
 composition remain unclear. Grassland fires account for roughly 80% of
 global annual fires, but only roughly 12% of research on belowground
 impacts of fires occurs in grasslands, limiting our understanding of
 aboveground belowground connections in these important habitats. Here, we
 took advantage of the serendipitous opportunity of a wildfire burning
 through the same reserve where we had previously sampled a prescribed
 burn. This enabled us to investigate the impacts of a spring prescribed
 burn versus a fall wildfire on plant cover and community composition and
 bacterial and fungal richness, abundance, and composition. Our California
 grassland sites were thus within the same reserve, limiting environmental,
 vegetation, or climate variation between the sites. We used qPCR of 16S
 and 18S to assess impacts on bacterial and fungal abundance and Illumina
 MiSeq of 16S and ITS2 to assess impacts on bacterial and fungal richness
 and composition. Wildfire had stronger impacts than prescribed burns on
 microbial communities and both fires had similar impacts on plants with
 both prescribed and wildfire reducing exotic plant cover but neither
 reducing exotic plant richness. Fungal richness declined after the
 wildfire but not prescribed burn, but bacterial richness was unaffected by
 either. Yet, fire exposure in both fire types resulted in reduced
 bacterial and fungal abundance and altered bacterial and fungal
 composition. Plant diversity differentially impacted soil microbial
 diversity, with exotic plant diversity positively impacting bacterial
 richness and having no effect on arbuscular mycorrhizal richness. However,
 the remainder of the soil microbial communities were more related to
 aspects of soil chemistry including cation exchange capacity, organic
 matter, pH and phosphorous. Our coupled plant and soil community sampling
 allowed us to capture the sensitivity to fire of the fungal community and
 highlights the importance of potentially incorporating management actions
 such as soil or fungal amendments to promote this critical community that
 mediates native plant performance.
description: <strong>APSoil_file column header
 metadata.txt</strong> This is a central file that
 has column header descriptions for the Dryad data files.
 <strong>APSoil_SpringPlantdata.csv</strong>
 Plant species composition data for grassland plots in prescribed
 and wildfire study sites. It includes plots that were exposed to fire
 (i.e. burned) and those not (i.e. unburned). Data were collected in the
 first spring after the respective fire. Six letter species codes are used
 for column headers.  Full species names for species codes can be found in
 APSoil_Plant Species List.csv Columns for species diversity response
 variables are also included in that are stratified across the entire
 community or based on species provenance (i.e. native or
 exotic). <strong>APSoil_Plant Species
 List.csv</strong> Provides full species names for
 any plant species observed during the study. A "NA" value was
 given for any species that had no field observation notes.
 <strong>APSoil_Bacterial-Metadata-withsoilPCA_final.csv</strong> Bacterial richness, diversity and abundance response variables for grassland plots sampled in prescribed and wildfire study sites that were either exposed to fire or not. Data are reported for multiple time points and file includes soil chemistry data and soil PCA axis scores that were used for data analysis. Soil samples were only collected for first time point after fire; thus the soil variables for other timepoints are listed as NA.  <strong>APSoil_otu_Bacteria_16S_rarefied data.csv</strong> Bacterial OTU table after rarefication adjustments. The first column is a sample ID key that can be connected to plot treatment information found in APSoil_Bacterial-Metadata-withsoilPCA_final.csv <strong>APSoil_Fungal-Metadata-withsoilPCA_final.csv</strong> Fungal richness, diversity and abundance response variables for grassland plots sampled in prescribed and wildfire study sites that were either exposed to fire or not. Data are reported for multiple time points and file includes soil chemistry data and soil PCA axis scores that were used for data analysis. Soil samples were only collected for first time point after fire; thus the soil variables for other timepoints are listed as NA. <strong>APSoil_otu_Fungal_ITS_rarefied data.csv</strong> Fungal OTU table after rarefication adjustments. The first column is a sample ID key that can be connected to plot treatment information found in APSoil_Fungal-Metadata-withsoilPCA_final.csv <strong>APSoil_AMF data.csv</strong> Compiled data file that has summary spring plant richness and diversity metrics and richness, diversity metrics for arbuscular fungal mycorrhizae