Assessing the effects of a drought experiment on the reproductive phenology and ecophysiology of a wet tropical rainforest community
Journal Publication ResearchOnline@JCUAbstract
Climate change is expected to increase the intensity and occurrence of drought in tropical regions, potentially affecting the phenology and physiology of tree species. Phenological activity may respond to a drying and warming environment by advancing reproductive timing, and/or diminishing the production of flowers and fruits. These changes have the potential to disrupt important ecological processes, with potentially wide-ranging effects on tropical forest function. Here, we analysed the monthly flowering and fruiting phenology of a tree community (337 individuals from 30 species) over seven years in a lowland tropical rainforest in north-eastern Australia, and its response to a through fall exclusion drought experiment (TFE) that was carried out from 2016 to 2018 (three years), excluding approximately 30% of rainfall. We further examined the eco-physiological effects of the TFE on the elemental (C:N) and stable isotope (d13C and d15N) composition of leaves, and on the stable isotope composition (d13C and d18O) of stem wood of four tree species. At the community level, there was no detectable effect of the TFE on flowering activity overall but there was a significant effect recorded on fruiting and varying responses from the selected species. The reproductive phenology and physiology of the four species examined in detail were largely resistant to impacts of the TFE treatment. One canopy species in the TFE significantly increased in fruiting and flowering activity whereas one understory species decreased significantly in both. There was a significant interaction between the TFE treatment and season on leaf C:N for two species. Stable isotope responses were also variable among species, indicating species-specific responses to the TFE. Thus, we did not observe consistent patterns in physiological and phenological changes in the tree community within the three years of TFE treatment examined in this study.
Journal
Conservation Physiology
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Volume
11
ISBN/ISSN
2051-1434
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Issue
1
Pages Count
14
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Publisher
Oxford University Press
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DOI
10.1093/conphys/coad064