Midday dew – an overlooked factor enhancing photosynthetic activity of corticolous epiphytes in a wet tropical rain forest

Authors

  • Michael Lakatos,

    1. Department of Plant Ecology and Systematics, Faculty of Biology, University of Kaiserslautern, PO Box 3049, D-67653 Kaiserslautern, Germany
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  • André Obregón,

    1. Laboratory for Climatology and Remote Sensing (LCRS), Department of Geography, University of Marburg, Deutschhausstr. 12, 35032 Marburg, Germany
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  • Burkhard Büdel,

    1. Department of Plant Ecology and Systematics, Faculty of Biology, University of Kaiserslautern, PO Box 3049, D-67653 Kaiserslautern, Germany
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  • Jörg Bendix

    1. Laboratory for Climatology and Remote Sensing (LCRS), Department of Geography, University of Marburg, Deutschhausstr. 12, 35032 Marburg, Germany
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Author for correspondence:
Michael Lakatos
Tel: +49 631 205 4448
Email: lakatos@rhrk.uni-kl.de

Summary

  • Additional water supplied by dew formation is an important resource for microbes, plants and animals in precipitation-limited habitats, but has received little attention in tropical forests until now.
  • We evaluated the micro-environmental conditions of tree stem surfaces and their epiphytic organisms in a neotropical forest, and present evidence for a novel mechanism of diurnal dew formation on these surfaces until midday that has physiological implications for corticolous epiphytes such as lichens.
  • In the understorey of a lowland forest in French Guiana, heat storage of stems during the day and delayed radiative loss during the night decreased stem surface temperatures by 6°C in comparison to the dew-point temperature of ambient air. This measured phenomenon induced modelled totals of diurnal dew formation between 0.29 and 0.69 mm d−1 on the surface of the bark and the lichens until early afternoon.
  • Crustose lichens substantially benefit from this dew formation, because it prolongs photosynthetic activity. This previously unrecognized mechanism of midday dew formation contributes to the water supply of most corticolous organisms, and may be a general feature in forest habitats world-wide.

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