DOI: 10.5061/dryad.59zw3r2cm
title: Dataset from: Functional traits explain both seedling and adult plant spatial patterns in gypsum annual species

description: 1. Ecological processes such as seed dispersal or plant–plant interactions
 and environmental constraints such as climate or soil heterogeneity are
 known to influence establishment, and thus the spatial patterns of plant
 communities and populations. In this study, we hypothesized that key
 functional traits such as the specific leaf area (SLA), reproductive ratio
 (reproductive/vegetative biomass), seed mass, and maximum plant height
 would influence the spatial patterns of individual species in annual,
 gypsophilous plant communities, and that these effects would be modulated
 by both the soil surface structure (biocrust) and climate (precipitation)
 conditions. 2. We mapped the spatial patterns of all plants found in six 1
 x 1 m plots (more than 1000 individuals per plot) in both the seedling
 (autumn) and adult stages (spring) under two biocrust experimental
 conditions (intact vs disturbed biocrust) during two consecutive years
 which were contrasted in term of precipitation (dry year and wet year). To
 assess the spatial patterns of seedlings and adults, we fitted four
 different spatial point pattern models (i.e., Poisson, inhomogeneous
 Poisson, Poisson cluster, and inhomogeneous Poisson cluster processes) to
 each of the 242 populations of the 27 most abundant species that had more
 than 15 individuals per plot. 3. Most seedling populations exhibited
 clustered spatial patterns that persisted in the adult stage, which
 suggests that short-distance dispersal is an adaptive trait for soil
 specialists such as gypsophilous plants. One-third of the populations
 fitted an inhomogeneous model best, but the physical structure of the
 biocrust was not related to them. More importantly, we found a connection
 between the functional strategies of species and the spatial distribution
 of plants. In particular, during the dry year, irrespective of the
 biocrust conditions, species with a high SLA and high Rep/Veg mainly
 exhibited clustered spatial patterns, whereas low SLA and low Rep/Veg were
 associated with random distributions. Species with heavy and light seed
 masses had random and clustered patterns, respectively. In both the dry
 and wet years, species with lower maximum heights had clustered patterns,
 whereas taller species exhibited random patterns. In addition, species
 with heavier seeds and greater maximum heights had the largest cluster
 sizes. 4. Our results confirm that the spatial patterns of seedlings and
 adult plants are significantly determined by the functional strategy of
 each species.
description: This data set was collected in
 a flat zone on the top of a gypsum hill in El Espartal (Valdemoro, Madrid,
 Central Spain, 40°11'11.5" N 3°37'47.0" W). Six plots
 (<strong>plot</strong>,
 "<strong>P1</strong>" to
 "<strong>P6</strong>"), either 1x 1 m or 1 x 1.2 m 
 were randomly distributed in a flat area of around 0.4 ha avoiding small
 holes or depressions, where the main microtopographic differences were
 created by the Biological Soil Crust (<strong>BSC</strong>).
 In three of the plots, the BSC was kept intact
 ("<strong>intact</strong>"), and in the other three
 plots, the BSC was thoroughly destroyed (i.e.,
 "<strong>perturbed</strong>"). We monitored every
 plant species (<strong>sp</strong>) that emerged in each plot
 in two consecutive years (<strong>year</strong>), which we
 designated as"<strong>year1</strong>" and
 "<strong>year2</strong>".  Each year, we sampled
 each plot twice to register the spatial patterns of plants in two
 different stages (<strong>stage</strong>), i.e.
 "<strong>seedling</strong>" or
 "<strong>adult</strong>". In total, we performed 4
 censuses (<strong>time</strong> 1 to 4) in each plot.
 During each census, we
 mapped the <strong>x</strong> and
 <strong>y</strong> coordinates of every plant species in the
 six plots. . Four functional traits, i.e., specific leaf area
 (<strong>SLA</strong>), reproductive to vegetative ratio
 (<strong>reproductive</strong>.<strong>ratio</strong>), seed mass (<strong>seed</strong>.<strong>mass</strong>) and maximum plant height (<strong>max</strong>.<strong>height</strong>)  were estimated based on at least 10 healthy undamaged individuals per species, which were randomly collected during the spring outside sampling plots surrounding our study area (see Peralta et al., 2019 for more details). All traits were measured according to the protocols described by Cornelissen et al. (2003) and Pérez-Harguindeguy et al. (2013).