Broad- and small-scale environmental gradients drive variation in chemical, but not morphological, leaf traits of vascular epiphytes

Variation in leaf functional traits along environmental gradients can reveal how vascular epiphytes respond to broad- and small-scale environmental gradients. Along elevational gradients, both temperature and precipitation likely play an important role as drivers of leaf trait variation, but these traits may also respond to small-scale changes in light, temperature, and humidity along the vertical environmental gradient within forest canopies. However, the relative importance of broad- and small-scale environmental gradients as drivers of variation in leaf functional traits of vascular epiphytes is poorly understood. Here, we examined variation in morphological and chemical leaf traits of 102 vascular epiphyte species spanning two environmental gradients along Cofre de Perote mountain in Mexico: i) a broad-scale environmental gradient approximated by elevation as well as by species’ lower and upper elevational limits, and ii) small-scale environmental gradients using the relative height...