10.5061/DRYAD.Q2BVQ83J6
Wright, Cynthia
0000-0003-2571-7334
Texas A&M University
Lima, André
Federal Rural University of Pernambuco
Souza, Eduardo
Federal Rural University of Pernambuco
West, Jason
Texas A&M University
Wilcox, Bradford
Texas A&M University
Data from: Plant functional types broadly describe water use strategies in
the Caatinga, a seasonally dry tropical forest in northeast Brazil
Dryad
dataset
2021
National Science Foundation
https://ror.org/021nxhr62
DGE‐1252521
United States Department of Energy
https://ror.org/01bj3aw27
DE-AC05-1008 00OR22725
Fundação de Amparo à Ciência e Tecnologia de Pernambuco
https://ror.org/02te5rf52
APQ-0296-5.01/17; APQ-0498-3.07/17 NOWCDCB; APQ-0532-5.01/14
Institute of International Education
https://ror.org/05s5kq870
2017 David L. Boren Fellowship
2022-05-03T00:00:00Z
2022-05-03T00:00:00Z
en
https://doi.org/10.1002/ece3.7949
33283 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
In seasonally dry tropical forests, plant functional type can be
classified as deciduous low wood density, deciduous high wood density, or
evergreen high wood density species. While deciduousness is often
associated with drought-avoidance and low wood density is often associated
with tissue water storage, the degree to which these functional types may
correspond to diverging and unique water use strategies has not been
extensively tested. We examined (1) tolerance to water stress, measured
by pre-dawn and mid-day leaf water potential; (2) water use efficiency,
measured via foliar δ13C; and (3) access to soil water, measured via stem
water δ18O. We found that deciduous low wood density species maintain high
leaf water potential and low water use efficiency. Deciduous high wood
density species have lower leaf water potential and variable water use
efficiency. Both groups rely on shallow soil water. Evergreen high wood
density species have low leaf water potential, higher water use
efficiency, and access alternative water sources. These findings indicate
that deciduous low wood density species are drought avoiders, with a
specialized strategy for storing root and stem water. Deciduous high wood
density species are moderately drought tolerant, and evergreen high wood
density species are the most drought tolerant group. Synthesis. Our
results broadly support the plant functional type framework as a way to
understand water use strategies, but also highlight species-level
differences.
Leaf water potential was measured using a Scholander pressure chamber
(1505D, PMS Instrument Company, Albany, OR) for leaves collected at
pre-dawn (4:30–6:00 AM) and at mid-day (11:30–1:00 PM). The leaves were
bagged and kept in cooler with ice, then immediately measured in-situ.
For foliar δ13C analysis, the additional leaves collected at
pre-dawn were oven-dried in the lab at 75°C to 80°C for at least 48
hours, then transported to the Stable Isotopes for Biosphere Science
(SIBS) Laboratory at Texas A&M University, College Station, for
grinding, weighing, and packing. These samples were analyzed for δ13C with
an Elemental Analyzer (Costech Analytical Technologies, Valencia, CA)
coupled to a Thermo Scientific Delta V Isotope Ratio Mass Spectrometer
(EA-IRMS; Thermo Fisher Scientific, Waltham, MA). Soil and stem samples
representing wet conditions were collected on April 10, 2018, and those
representing dry conditions were collected on June 12, 2018. Samples for
the evergreen species group were collected separately on September 19,
2018. The soil samples from seven pits at three integrated depths: 5–15
cm, 20–30 cm, and 40–50 cm. Soil and stem water was extracted via
cryogenic vacuum distillation at 100°C. Rainwater and throughfall samples
were collected approximately bi-weekly from January 18, 2018 until June 9,
2018 (Fig. 1) in collectors wrapped with aluminum foil filled with a thin
layer of paraffin oil to reduce evaporation (IAEA, 2014). Groundwater and
surface water samples were also collected from the surrounding area. Water
samples containing debris were filtered (0.2 μm) to remove particles. All
water samples were analyzed using a High Temperature Conversion/Elemental
Analyzer coupled to a Delta V Advantage Isotope Ratio Mass Spectrometer
(TC/EA-IRMS). Please see corresponding publication for more details.
Missing data is marked as NA. Data has been summarized (mean and standard
deviation) by date and tree species or sample ID.