Plant size and leaf traits for epiphyte species found in flooded gallery forests and non-flooded gallery forests in Central Brazil

<p>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.  </p>