DOI: 10.5061/dryad.83bk3j9zt
title: Simplification of plant trait networks among communities along a climatic aridity gradient

description: Plant ecological strategies are shaped by numerous functional traits and
 their tradeoffs. Trait network analysis enables testing hypotheses for the
 shifting of trait correlation architecture across communities differing in
 climate and productivity. We built plant trait networks (PTNs)
 for 118 species within six communities across an aridity gradient, from
 forest to semi-desert across the California Floristic Province based on 34
 leaf and wood functional traits, representing hydraulic and photosynthetic
 function, structure, economics, and size. We developed hypotheses for the
 association of PTN parameters with climate and ecosystem properties, based
 on theory for the adaptation of species to low resource/stressful
 environments, versus higher resource availability with greater potential
 niche differentiation. Thus, we hypothesized that across community PTNs,
 trait network connectivity (i.e., the degree traits are intercorrelated)
 and network complexity (i.e., the number of trait modules, and the degree
 of trait integration among modules) would be lower for communities adapted
 to arid climates, and higher for communities adapted to greater water
 availability, similarly to trends expected for phylogenetic diversity,
 functional richness and productivity. Further, within given PTNs, we
 hypothesized that traits would vary strongly in their network connectivity
 and that the traits most centrally connected within PTNs would be those
 with the least across-species variation. Across communities from more arid
 to wetter climates, PTN architecture varied from less to more
 interconnected and complex, in association with functional richness, but
 PTN architecture was independent of phylogenetic diversity and ecosystem
 productivity. Within community PTNs, traits with lower species variation
 were more interconnected.   Synthesis.  The
 responsiveness of PTN architecture to climate highlights how a wide range
 of traits contribute to physiological and ecological strategies with an
 architecture that varies among plant communities. Communities in more arid
 environments show a lower degree of phenotypic integration, consistent
 with lesser niche differentiation. Our study extends the usefulness of
 PTNs as an approach to quantify tradeoffs among multiple traits, providing
 connectivity and complexity parameters as tools that clarify plant
 environmental adaptation and trait associations that would influence
 species distributions, community assembly and ecosystem resilience in
 response to climate change.
description: We sampled three to five
 individuals per species, resulting in a total of 683 individuals from 118
 unique species in six plant communities distributed across a gradient of
 climatic aridity, differing by 10 <sup>o</sup>C in mean annual
 temperature (MAT) and 6-fold in mean annual precipitation (MAP). The sites
 also varied strongly in soil characteristics and plant community
 composition. We targeted the most abundant tree and shrub species at each
 site, based on information from reserve managers and forest inventories.
 The sampling spanned 37 families, with greatest species representation in
 Asteraceae (17), Rosaceae (12), Rhamnaceae (9), Ericaceae (8) and Pinaceae
 (8). At each site we sampled from 19 to 28 species, collecting a mature,
 sun-exposed and non-epicormic branch, with no signs of
 damage and herbivory using pole pruners or a slingshot.
 Branches were transported to the lab in dark plastic bags with moist paper
 and rehydrated overnight in a dark saturated atmosphere before harvesting
 current-year grown, fully expanded leaves for subsequent analyses. For
 compound-leafed species, whole leaves, not leaflets, were used.
description: # Simplification of plant trait networks among communities along a
 climatic aridity gradient #### Description of the Data and file structure
 Note 1: Missing values were coded as NAs across all data sheets. Note 2:
 The file names match those used in the data analysis script linked in the
 paper and hosted in the Zotero platform. Note 3: The legend for the
 supplemental files included in the paper is extensive, so we provide it in
 a separate file ("File 1") Here we provide 14 separate files: *
 File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_legend.csv Description: Legend of all trait/parameter symbols included across all supplemental files, with complete categorical variable or species trait or community network parameter or environmental variable names, descriptions, symbols and units - File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_individualTraits.csv Description: Raw trait data for each sampled individual included in this study. The legend for all included variables and units is presented in "File 1" described above. * File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_speciesTraits.csv Description: Trait data averaged at the species-level. The legend for all included variables and units is presented in "File 1" described above. - File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_PTNparameters_climate.csv Description: Community plant trait network parameters, geographical coordinates and environmental variables of the sampled sites. The legend for all included variables and units is presented in "File 1" described above. * File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_measurementCategories.csv Description: Plant trait network parameters of the network build including species across all six sites averaged by measurement category (Epidermal morphology, 4 traits; Leaf economics, 5 traits; Wood economics, 1 trait; leaf composition, 21 traits; Hydraulics, 1 trait; Plant size, 2 traits). The legend for all included variables and units is presented in "File 1" described above. - File:Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_trait-levelNetworkParameters.csv Description: Trait-level parameters extracted from the plant trait networks build for each of the six sampled sites. The legend for all included variables and units is presented in "File 1" described above. * File: Medeiros_Simplification_of_woody_plant_trait_networks_among_communities_along_a_climatic_aridity_gradient_TraitNodeCV.csv Description: Trait coefficients of variation, CV, and trait-level parameters extracted from the plant trait networks build including species across all six sites (_all) and the networks build for each of the six sampled sites (_site code). The legend for all included variables and units is presented in "File 1" described above. - 8-14. Files: states.sbn, states.prj, states.avl, states.shx, states.sbx, states.dbf, states.shp Description: Files needed to subset the Worldmap to the US area in the data analysis script liked to this manuscript and hosted in Zotero. The code refers to "states.shp" only, but all 7 files named "states" need to be present in the folder.