DOI: 10.5061/dryad.j3tx95xc8
title: Plant size and leaf traits for epiphyte species found in flooded gallery forests and non-flooded gallery forests in Central Brazil

description: Despite their unique adaptations to thrive in canopy environments without
 access to soil resources, epiphytes are underrepresented in studies of
 functional traits and of functional composition of tropical plant
 communities. We investigated functional traits of spermatophytic
 (seed-bearing) C3 and CAM epihyte communities in flooded and non-flooded
 gallery forests in Central Brazil. The two forest types differ in
 floristic, structure, microclimate and edaphic conditions. We studied
 plant size, leaf thickness, leaf dry matter content, leaf area, specific
 leaf area, leaf C, N, P, K, Mg, Ca and C and N stable isotope ratios.
 Because photosynthetic pathway (C3 or CAM) is an important aspect of
 ecologial differentiation of spermatophytic epiphytes, we expected that
 functional trait syndromes in a multivariate space would be more
 associated with photosynthetic pathway than forest type and changes in
 abundance of C3 and CAM epiphytes would drive functional trait composition
 at the community level. C3 and CAM epiphytes segregated in the
 multivariate trait space, however, more complex functional typologies were
 also evident. Despite lower light levels, CAM epiphytes were more abundant
 in the flooded gallery forest. There, they accounted for 80% of all
 individuals, whereas C3 epiphytes dominated in the non-flooded forest.
 These large differences in the proportion of C3 and CAM epiphytes strongly
 affected functional trait values at the community level, despite very
 little intraspecfic variation in trait values between forest types for
 species that occurred in both forests.  
description: Field work was carried out in a flooded and a non-flooded gallery
 forest in the Federal District, in Central Brazil. The flooded gallery
 forest site (FGF) follows the <em>Taquara/Onça</em> streams
 (15º55’28” S, 47º54’56” W) and the non-flooded gallery forest site (NFGF)
 follows the <em>Capetinga </em>stream (15º57’16” S, 47º56’29”
 W). We collected leaf samples of nine epiphyte species in each gallery
 forest during the dry season, between July and August of 2018. All
 individuals were collected close to the main trunk at the lower crown zone
 (between 7 m and 10 m aboveground), which represents the center zone of
 the host tree crown. We selected three fully mature, non-senescent leaves
 of each individual to assess leaf traits. We measured plant size (cm),
 leaf thickness (mm), leaf area (LA; cm<sup>2</sup>), specific
 leaf area (SLA; cm<sup>2</sup>/g), leaf dry matter content
 (LDMC; mg/g) and leaf water content (LWC; g/cm<sup>2</sup>).
 The average of the three values was used as the trait value for each
 individual. For elemental analysis, all samples (replicate leaves of each
 individual combined) were homogenized in a ball mill. Leaf phosphorus (P;
 %) concentrations were determined following the protocol outlined in Chen
 et al. (Chen, P.S., Toribara, T.Y., & Warner, H. (1956).
 Microdetermination of phosphorus. <em>Analytical
 Chemistry</em>, 28, 1756-1758), while leaf calcium (Ca; %),
 potassium (K; %) and magnesium (Mg; %) were determined with a flame atomic
 absorption spectrophotometer AAS240AA (Agilent Technologies, Waldbronn,
 Germany) after digestion of samples following standard procedures. Leaf
 carbon (C; %) and nitrogen (N; %), as well as C and N isotope composition
 (?<sup>13</sup>C and ?<sup>15</sup>N; ‰) were
 determined with a continuous-flow isotope ratio mass spectrometry (IRMS)
 system.