DOI: 10.5061/dryad.rr4xgxd9p
title: Taxonomic and functional compositions and environmental data of 19 seedling assemblages in a Caatinga dry forest

description: We used these information to assess the structure, composition,
 and diversity of woody seedling assemblages across 19 forest stands in a
 human-modified landscape of Caatinga dry forest, assessing the role played
 by rainfall, aboveground biomass, and chronic anthropogenic disturbances
 (i.e., livestock grazing pressure and wood extraction) as assembly forces.
 We quantified a large set of community-level attributes including
 functional traits related to water availability, physical protection, and
 survival success. We recorded a total of 544 seedlings from 59 species.
description: The mean annual rainfall of each forest stand was obtained from
 the WorldClim repository (www.worldclim.org),
 with rainfall data resolution of 30 arc seconds (equivalent to 1 km). Mean
 annual rainfall ranged from 510 mm to 940 mm. Aboveground biomass was
 obtained from Souza <i>et al</i>. (2019). We adopted two
 chronic anthropogenic indices from Arnan <i>et al</i>. (2018)
 that integrate indirect measures of geographical (i.e., proximity to
 houses and roads) and socio-ecological metrics (i.e., number of people,
 livestock, and firewood use), and direct field measures (i.e., goat and
 cattle dung, wood extraction) for each forest stand. The indices are the
 1) wood extraction index, including field measurements of live and
 firewood collection and use, and (2) livestock pressure, including data on
 livestock dung, trail length, which reflects the trampling and other
 physical damage by cattle and goats (see Arnan <i>et al</i>.
 2018 for detailed information). Seedling assemblages
 were recorded across 19 0.1-ha (20 m × 50 m) old-growth forest stands that
 form part of the Catimbau Long-Term Ecological Research project
 (www.peldcatimbau.org). Stands are separated by a minimum distance of 2 km
 and spread over 214 km<sup>2</sup>. To assign a plant as a
 seedling, we dug each plant with height ≤ 50 cm and collected the
 individuals that (1) did not display any reproductive organs (i.e., flower
 buds, flowers, or fruits) and (2) were not root suckers or sprouts (i.e.,
 connected to root buds or sprouting stems). All the seedlings within each
 of the 19 forest stands were collected during two months during the rainy
 season of 2018 (July-August). The traits were measured
 from seedlings collected in 19 50 m x 20 m (0.1 ha) forest stands in a dry
 forest. All the seedlings below 50 cm of height were collected and traits
 measured in the laboratory. Surveys were restricted to woody plants
 species. Eight functional leaf traits were measured:
 (1) leaf area (LA, cm²); (2) specific leaf area (SLA, the ratio of leaf
 area to leaf dry mass, m²/kg); (3) leaf dry matter content (LDMC, the
 ratio of leaf dry mass to fresh mass, mg/g); (4) leaf thickness (Lth, mm);
 (5) leaf succulence (LS, the ratio of leaf water content to leaf area,
 mg/cm²); (6) leaf compoundness (LC, 0 - simple leaves; 1 - compound
 leaves); (7) spinescence (Spin, 0 - absent, 1 - present); (8)
 presence/absence of trichomes (Trich, 0 - absent, 1 - present). The
 collected data of traits 1-8 were collected in the field for each
 individual according to Pérez-Harguindeguy et al. (2013).