Host tree phenology affects vascular epiphytes at the physiological, demographic and community level

Tree phenology imposes an imprint on epiphyte assemblages from leaf physiology to community composition (Photo credit: Helena Einzmann)
Tree phenology imposes an imprint on epiphyte assemblages from leaf physiology to community composition (Photo credit: Helena Einzmann)

The processes that govern diverse tropical plant communities have rarely been studied in life-forms other than trees. Structurally dependent vascular epiphytes, a major part of tropical biodiversity, grow in a three-dimensional matrix defined by their hosts, but these host trees differ in many ways, not least in leaf phenology. In a recent study published in AoB PLANTS, Einzmann et al. hypothesized that differences in microclimatic conditions in evergreen vs. deciduous trees would affect epiphytes at various levels, from organ physiology to community structure. Indeed, they found that deciduous tree species hosted less abundant and species-poorer epiphyte assemblages. Physiologically, epiphyte assemblages differed in the proportion of CAM species and individuals, and in SLA and δ13C values. Effects were also detectable at a demographic level, i.e. in growth and survival rates. Their results thus suggest a cascading effect of tree composition and associated differences in tree phenology on the diversity and functioning of epiphyte communities in tropical lowland forests.