Differences in Leaf Temperature between Lianas and Trees in the Neotropical Canopy

J Guzmán Q,Benoit Rivard,G Sánchez-Azofeifa

doi:10.3390/f9060307

Abstract

Leaf temperature (Tleaf) influences photosynthesis and respiration. Currently, there is a growing interest in including lianas in productivity models due to their increasing abundance and their detrimental effects in the carbon stock of tropical ecosystems. Therefore, understanding the differences of Tleaf between lianas and trees is important for future predictions of productivity. Here, we determined the displayed leaf temperature (Td = Tleaf − air temperature) of several species of lianas and their host trees during El Niño-Southern Oscillation (ENSO) and non-ENSO years to evaluate if the presence of lianas affects the Td of their host trees, and if leaves of lianas and their host trees exhibit differences in Td. Our results suggest that close to midday, the presence of lianas does not affect the Td of their host trees; however, lianas tend to have higher values of Td than their hosts across seasons, in both ENSO and non-ENSO years. Although lianas and trees tend to have similar physiological-temperature responses, differences in Td could lead to significant differences in rates of photosynthesis and respiration based on temperature response curves. Future models should thus consider differences in leaf temperature between these two life forms to achieve robust predictions of productivity.

Highlights

Variations in leaf temperature (Tleaf ) have been considered a factor that can affect the net primary productivity of the biosphere
We have shown that the presence of lianas may not affect the leaf temperature of their host trees; lianas leaves tend to have higher values of temperature than their host trees
Our results highlight this difference in the expression of the temperature of lianas as an important biotic factor at the canopy level that can influence the forest temperature; their differential expression may have a significant weight in future predictions of forest productivity

Summary

Introduction

Variations in leaf temperature (Tleaf ) have been considered a factor that can affect the net primary productivity of the biosphere. In tree communities of temperate regions, Leuzinger & Körner [2] have found that the presence or absence of certain tree species in the canopy can play a significant role in the control of the forest surface temperature. This control depends in large part on the spatial arrangement and leaf functional traits of such species, such as the stomatal conductance and the capacity of leaf cooling associated with water transpiration [3,4,5]. There is no concrete evidence of how the spatial arrangement of species can affect the forest surface temperature of a tropical forest; it could be expected that the high diversity of species, life forms, and functional traits produce a highly dynamic surface temperature that could reduce our ability to predict different ecological processes

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