Drought reduces the growth and health of tropical rainforest understory plants

Tng, David Y.P., Apgaua, Deborah M.G., Paz, Claudia P., Dempsey, Raymond W., Cernusak, Lucas A., Liddell, Michael J., and Laurance, Susan G.W. (2022) Drought reduces the growth and health of tropical rainforest understory plants. Forest Ecology and Management, 511. 120128.

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Abstract

Tree saplings and shrubs are frequently overlooked components of tropical rainforest biodiversity, and it may be hypothesized that their small stature and shallow root systems predisposes them to be vulnerable to drought. However, these purported influences of drought on growth, physiological performance and plant traits on tree saplings and shrubs have yet to be studied in simulated drought conditions in the field. We simulated drought using a rainfall exclusion experiment in 0.4 ha of lowland tropical rainforest in northeast Australia in 2015. After six months, we compared the average change in aboveground biomass and plant health of drought-affected tree saplings and understory shrubs with control individuals. We also assessed photosynthetic function, plant health and leaf traits in eight target species. Both tree saplings and shrubs had significantly lower aboveground biomass in the drought treatment compared to the control. Drought-affected individuals of target species exhibited a significantly higher incidence of disease and insect attack, and reduced photosynthesis, leaf fresh mass and leaf toughness compared to control individuals. We conclude that reduced growth and photosynthetic capability, an increased susceptibility to insect attack, and leaf trait changes constitute a near immediate drought response in tropical rainforest tree saplings and shrubs. Our results show that these often-overlooked lifeforms are likely to be the most rapidly and negatively impacted component of tropical rainforest biodiversity under drought conditions.

Item ID: 76157
Item Type: Article (Research - C1)
ISSN: 1872-7042
Copyright Information: © 2022 Elsevier B.V. All rights reserved.
Funders: Australian Research Council (ARC)
Projects and Grants: ARC FT130101319
Date Deposited: 04 Oct 2022 05:42
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310308 Terrestrial ecology @ 50%
41 ENVIRONMENTAL SCIENCES > 4101 Climate change impacts and adaptation > 410102 Ecological impacts of climate change and ecological adaptation @ 50%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180601 Assessment and management of terrestrial ecosystems @ 100%
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