Shock and stabilisation following long-term drought in tropical forest from 15 years of litterfall dynamics
da Costa, ACL
Journal of Ecology
Wiley for British Ecological Society
© 2018 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
1.Litterfall dynamics in tropical forests are a good indicator of overall tropical forest function, indicative of carbon invested in both photosynthesising tissues and reproductive organs such as flowers and fruits. These dynamics are sensitive to changes in climate, such as drought, but little is known about the long-term responses of tropical forest litterfall dynamics to extended drought stress. 2.We present a 15-year dataset of litterfall (leaf, flower and fruit, and twigs) from the world's only long-running drought experiment in tropical forest. This data set comprises one of the longest published litterfall time-series in natural forest, which allows the long-term effects of drought on forest reproduction and canopy investment to be explored. 3.Over the first four years of the experiment, the experimental soil moisture deficit created only a small decline in total litterfall and leaf fall (12% and 13% respectively), but a very strong initial decline in reproductive litterfall (flowers and fruits) of 54%. This loss of flowering and fruiting was accompanied by a de-coupling of all litterfall patterns from seasonal climate variables. However, following >10 years of the experimental drought, flower and fruiting re-stabilised at levels greater than in the control plot, despite high tree mortality in the drought plot. Litterfall relationships with atmospheric drivers were re-established alongside a strong new apparent trade-off between litterfall and tree growth. 4.Synthesis: we demonstrate that this tropical forest went through an initial shock response during the first four years of intense drought, where reproductive effort was arrested and seasonal litterfall patterns were lost. However, following >10 years of experimental drought this system appears to be re-stabilising at a new functional state where reproduction is substantially elevated on a per tree basis; and there is a new strong trade-off between investment in canopy production and wood production.
This work is a product of UK NERC grant NE/J011002/1 to PM and MM, UK NERC independent fellowship grant NE/N014022/1 to LR, CNPQ grant 457914/2013-0/MCTI/CNPq/FNDCT/LBA/ESECAFLOR to ACLD, an ARC grant DP17010409to PM. It was previously supported by NERC NER/A/S/2002/00487, NERC GR3/11706, EU FP5-Carbonsink and EU FP7-Amazalert to PM and a grant from the Gordon and Betty Moore Foundation to YM
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.
Published online 16 January 2018
Except where otherwise noted, this item's license is described as © 2018 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.