10.5061/DRYAD.KH189322M
Sousa, Thaiane
0000-0003-0598-4996
Instituto de Pesquisas da Marinha
Schietti, Juliana
National Institute of Amazonian Research
Coelho de Souza, Fernanda
University of Brasília
Esquivel-Muelbert, Adriane
University of Birmingham
Ribeiro, Igor
University of the State of Amazonas
Emilio, Thaise
State University of Campinas
Pequeno, Pedro
Universidade Federal de Roraima
Phillips, Oliver
University of Leeds
Costa, Flavia
National Institute of Amazonian Research
Palms and trees resist extreme drought in Amazon forests with shallow
water tables
Dryad
dataset
2020
water table
groundwater
Arecaceae
extreme events
2020-02-27T00:00:00Z
2020-02-27T00:00:00Z
en
44000 bytes
2
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. The intensity and frequency of severe droughts in the Amazon region has
increase in recent decades. These extreme events are associated with
changes in forest dynamics, biomass and floristic composition. However,
most studies of drought response have focused on upland forests with deep
water tables, which may be especially sensitive to drought. Palms, which
tend to dominate the less well-drained soils, have also been neglected.
The relative neglect of shallow water tables and palms is a significant
concern for our understanding of tropical drought impacts, especially as
one third of Amazon forests grow on shallow water tables (<5m
deep). 2. We evaluated the drought response of palms and trees in forests
distributed over a 600 km transect in central-southern Amazonia, where the
landscape is dominated by shallow water table forests. We compared
vegetation dynamics before and following the 2015-16 El Nino drought, the
hottest and driest on record for the region (-214 mm of cumulative water
deficit). 3. We observed no change in stand mortality rates and no biomass
loss in response to drought in these forests. Instead, we observed an
increase in recruitment rates, which doubled to 6.78% y-1 ± 4.40 (mean ±
SD) during 2015-16 for palms and increased by half for trees (to 2.92% y-1
± 1.21), compared to rates in the pre-El-Nino interval. Within these
shallow water table forests, mortality and recruitment rates varied as a
function of climatic drought intensity and water table depth for both
palms and trees, with mortality being greatest in climatically and
hydrologically wetter environments and recruitment greatest in drier
environments. Across our transect there was a significant increase over
time in tree biomass. 4. Synthesis: Our results indicate that forests
growing over shallow water tables – relatively under-studied vegetation
that nonetheless occupies one-third of Amazon forests - are remarkably
resistant to drought. These findings are consistent with the hypothesis
that local hydrology and its interactions with climate strongly constrain
forest drought effects, and has implications for climate change feedbacks.
This work enhances our understanding of integrated drought effects on
tropical forest dynamics and highlights the importance of incorporating
neglected forest types into both the modeling of forest climate responses
and into public decisions about priorities for conservation.
Metadata tab of each spreadsheet defines the variables.