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Radial distributions of air plants: a comparison between epiphytes and mistletoes
Author(s) -
Taylor Amanda,
Burns Kevin
Publication year - 2016
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/15-1322.1
Subject(s) - epiphyte , microclimate , humidity , light intensity , ecology , environmental science , biology , botany , atmospheric sciences , geography , geology , physics , meteorology , optics
Abstract Vertical gradients of light and humidity within forest canopies are major predictors of air plant distributions. Although this pattern was first recognized over 120 years ago, few studies have considered an additional axis of resource availability, which exists radially around the trunks of trees. Here, we explored the radial distributions of mistletoes and epiphytes in relation to gradients of light and humidity around the trunks of their south‐temperate host trees. Additionally, we correlated microclimate occupancy with plant physiological responses to shifting resource availability. The radial distributions of mistletoes and epiphytes were highly directional, and related to the availability of light and humidity, respectively. Mistletoes oriented northwest, parallel to gradients of higher light intensity, temperature, and lower humidity. Comparatively, epiphytes oriented away from the sun to the southeast. The rate of CO 2 assimilation in mistletoes and photochemical efficiency of epiphytes was highest in plants growing in higher light and humidity environments, respectively. However, the photosynthetic parameters of mistletoes suggest that they are also efficient at assimilating CO 2 in lower light conditions. Our results bridge a key gap in our understanding of within‐tree distributions of mistletoes and epiphytes, and raise further questions on the drivers of air plant distributions.