Abstract

SUSAN-TEPETLAN, Tania M.; VELAZQUEZ-ROSAS, Noé  and  KROMER, Thorsten. Changes in functional traits of vascular epiphytes of cloud forest and secondary vegetation in central Veracruz, México. Bot. sci [online]. 2015, vol.93, n.1, pp.153-163. ISSN 2007-4476.  https://doi.org/10.17129/botsci.228.

The abundance and diversity of epiphytic communities in the tropical montane cloud forests are commonly affected by anthropogenic disturbances. However, the exact causes triggering such changes in the communities have poorly been explored. Canopy structure changes is one of the main factors affecting the communities of epiphytes, but plant responses to micro-environmental factors are largely unknown. In a landscape dominated by anthropogenic changes, we aimed to understand the effects of microclimatic factors (temperature, relative humidity and photosynthetically active radiation) on the functional responses (variation in leaf area, leaf blade thickness, dry mass per unit area, leaf density and moisture content) of the ten most abundant species of epiphytes. This study was done in Central Veracruz, Mexico, and included a well-conserved cloud forest, a 20-year-old secondary forest and a shade coffee plantation. Hydric stress and radiation were correlated with canopy openness, being the coffee plantation the most stressful community for the epiphytes and the conserved forest the less stressful site. We detected plant specific functional responses to microclimatic factors, but in general, in the natural forest epiphytes presented thinner leaves with higher moisture content, lower dry mass and density, whereas in the coffee plantation the opposite pattern was found. Besides, understanding the functional responses of the species to the micro-environmental factors, the functional traits of the epiphytic communities were useful surrogates of the conservation status of the sites.

Keywords : bromeliads; conservation gradient; ferns; morpho-ecophysiological traits; orchids.

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