We identify changes in the functional composition of vascular epiphytes along a tropical elevational gradient with the aim of quantifying the role of climate in determining the assembly of epiphyte communities. We measured seven leaf functional traits (leaf area, specific leaf area, leaf dry-matter content, leaf thickness, force to punch, stomatal density, and potential conductance index) in the 163 most abundant epiphyte species recorded across 10 sites located along an elevational gradient between 60 and 2,900 m above sea level in the Colombian Andes. We grouped the epiphyte species into seven hierarchical functional groups according to their most characteristic leaf traits. Along the elevational gradient, the two main independent leaf trait dimensions that distinguished community assemblages were defined primarily by leaf area-photosynthetic (LAPS) and mass-carbon (LMCS) gradients. Mean annual temperature was the main determinant of species position along LAPS. In contrast, local changes in specific leaf area due to variation in the epiphytes' relative height of attachment was the main determinant of their position along the LMCS. Our findings indicate that epiphytic plant leaves have evolved to optimize and enhance photosynthesis through a leaf area-based strategy and carbon acquisition through investments in construction costs of leaf area per unit of biomass that aim to regulate light capture and tissue development. Given that most studies of plant functional traits neglect vascular epiphytes, our quantification of the multiple dimensions of epiphyte leaf traits greatly augments our understanding of vascular plant function and adaptation to changing environments.

This is an open access article under the terms of the Creat ive Commo ns Attri bution-NonCo mmercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

No abstract

Structure and floristic composition of mangroves in the Bahía de Cispatá, Colombian Caribbean. Mangroves are plant associations that are easily adapted to saline conditions and fluctuating levels of flooding. This ecosystem provides a wide variety of goods and services as carbon storage. Structural differences, species composition and micro-environmental characteristics between physiographic types involve differences in carbon storage in their soils. This research aimed to identify the variation of mangrove species through changes in the physical-biotic variables of mangrove forest of Cispatá bay, Colombia. We measured structural variables of forest (D, H, density of individuals) as well as physico-biotic variables (flood level, A. aureum coverage, water interstitial salinity, soil pH, % N, % COs, roots and apparent density soil) in 12 plots established randomly. With a CCA it was identified three mangroves: basin, fringe in good condition and fringe with anthropogenic intervention. The first was dominated by A. germinans and the others by R. mangle. The basin mangrove differs from fringe in physical-biotic variables and structurally, it presented the highest values of COs, salinity, apparent density and pH. Although the two fringe mangrove exhibit similar physical-biotic variables, human disturbance may strongly change the structure of one of them. It was concluded that the distribution of mangrove species of bay responds to a spatial variation in environmental characteristics. However, anthropogenic intervention is a determining variable in the structure of mangroves which affects estimations of the role of different types of mangrove forests as carbon sinks. Rev. Biol. Trop. 63 (4): 1137-1147. Epub 2015 December 01.