Soil and biomass data from: Soil, competition, and niche shifts shape the floral mosaic of an annual plant diversity hotspot

Plant species with affinity for harsh substrates often have well-defined edaphic (soil) niches and are ideal for exploring questions of community assembly. Vertic clay soils are chemically and physically challenging to plant establishment and productivity, and annual plant communities associated with these soils of the San Joaquin Desert (California, USA) form a distinctive mosaic pattern of species that reflects differences in soil properties across the landscape. We conducted field sampling and a pot study with 12 native annual forb species with an affinity for vertic clay soils to determine how heterogeneous soils at two sites in the San Joaquin Desert differed between realized niches of species, to test if species differed in their realized and fundamental edaphic niches, and to examine the competition effects of an invasive annual grass (Bromus rubens) on these species’ edaphic niches. From our field study, we found some differences in the vertic clay soils between the realized nic..., Data in \"dryad_fieldsoilsweighted_sitesseparate.csv\" and \"dryad_fieldsoilsweighted.csv\" was collected as follows\":
Field-collected soil samples from the species patches for each study species (hereafter referred to as their “home soils”) were collected from sites at Cantua Creek, Carrizo Plain, or both, based on species distribution and verifiability of species patches during field visits. For each species, we sampled approximately 0.5 L of rhizosphere soil from a maximum depth of 25 cm within the centroid of a species patch dominated by that species. Replicate sampling (n ≥ 5) for a single species was done at a minimum distance of 15 m and efforts made to ensure patches sampled for a single species were separated by one or more patches dominated by other species to avoid pseudo-replication. All soil samples were air-dried and sieved to 2 mm prior to analysis.
Soil samples collected from field sites and soils used for the pot study were analyzed by A&L Western Laboratories..., # Soil and biomass data from: Soil, competition, and niche shifts shape the floral mosaic of an annual plant diversity hotspot

Dataset DOI: [10.5061/dryad.ffbg79d67](https://doi.org/10.5061/dryad.ffbg79d67)

## Description of the data and file structure

We examined 12 native annual forb species associated with vertic clay soils in this study over two components: an observational field sampling campaign and an experimental pot study. To explore whether these species had realized niches defined by edaphic properties, we sampled soils from 5–10 patches per species at both Cantua Creek (Fresno County, California) and Carrizo Plain (San Luis Obispo County, California). We then analyzed the soil samples for physical and chemical properties to characterize the edaphic realized niche along the axes of those soil properties. If differences in edaphic properties were the primary determinant of the realized edaphic niches of our study species, we anticipated finding significant differences betwe...,