Abstract
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 (a) tolerance to water stress, measured by predawn and mid-day leaf water potential; (b) water use efficiency, measured via foliar δ13C; and (c) 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.
Original language | English |
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Pages (from-to) | 11808-11825 |
Number of pages | 18 |
Journal | Ecology and Evolution |
Volume | 11 |
Issue number | 17 |
DOIs | |
State | Published - Sep 2021 |
Funding
This work was supported by the Texas A&M Sid Kyle Endowment, the USDA‐NIFA Grant 12726253 and CAPES/TAMU (006/2014), and the National Observatory of Water and Carbon Dynamics in the Caatinga Biome—NOWCDCB, and supported by FACEPE (grants: APQ‐0296‐5.01/17; APQ‐0498‐3.07/17 NOWCDCB; APQ‐0532‐5.01/14), CNPq (grants: 435508/2018‐0; 312984/2017‐0), and CAPES (grants: 88887.136369/2017‐00). CLW was funded by the 2017 David L. Boren Fellowship, the NSF GRFP (DGE‐1252521), and the Next Generation Ecosystem Experiments‐Tropics (NGEE‐Tropics), funded by the U.S. Department of Energy, Office of Science, and by ORNL, managed by UT‐Battelle, LLC, for the DOE (contract DE‐AC05‐1008 00OR22725). We thank the undergraduate students at UAST who provided field assistance, including Erison Martins, Cléa Medeiros, Fernando Isaias, Hugo Felipe da Silva, and Lypson Simões. We also thank Dr. José Romualdo de Sousa Lima of the Universidade Federal Rural de Pernambuco, Unidade Académica de Garanhuns, for the Scholander pressure chamber, Rodolfo Souza of the Universidade Federal Rural de Pernambuco, Unidade Académica de Serra Talhada for access to hydrometeorology data, and Dr. Ayumi Hyodo for streamlining work at the Stable Isotopes for Biosphere Science laboratory at Texas A&M. We thank Homen Bom de Magalhães for field access. This work was supported by the Texas A&M Sid Kyle Endowment, the USDA-NIFA Grant 12726253 and CAPES/TAMU (006/2014), and the National Observatory of Water and Carbon Dynamics in the Caatinga Biome—NOWCDCB, and supported by FACEPE (grants: APQ-0296-5.01/17; APQ-0498-3.07/17 NOWCDCB; APQ-0532-5.01/14), CNPq (grants: 435508/2018-0; 312984/2017-0), and CAPES (grants: 88887.136369/2017-00). CLW was funded by the 2017 David L. Boren Fellowship, the NSF GRFP (DGE-1252521), and the Next Generation Ecosystem Experiments-Tropics (NGEE-Tropics), funded by the U.S. Department of Energy, Office of Science, and by ORNL, managed by UT-Battelle, LLC, for the DOE (contract DE-AC05-1008 00OR22725). We thank the undergraduate students at UAST who provided field assistance, including Erison Martins, Cléa Medeiros, Fernando Isaias, Hugo Felipe da Silva, and Lypson Simões. We also thank Dr. José Romualdo de Sousa Lima of the Universidade Federal Rural de Pernambuco, Unidade Académica de Garanhuns, for the Scholander pressure chamber, Rodolfo Souza of the Universidade Federal Rural de Pernambuco, Unidade Académica de Serra Talhada for access to hydrometeorology data, and Dr. Ayumi Hyodo for streamlining work at the Stable Isotopes for Biosphere Science laboratory at Texas A&M. We thank Homen Bom de Magalhães for field access.
Keywords
- drought stress and tolerance
- ecophysiology
- leaf water potential
- phenology and wood density
- plant functional types
- seasonally dry tropical forests
- stable isotope ratios
- water use strategies and resource acquisition trade-offs