Abstract
Deep-water access is arguably the most effective, but under-studied, mechanism that plants employ to survive during drought. Vulnerability to embolism and hydraulic safety margins can predict mortality risk at given levels of dehydration, but deep-water access may delay plant dehydration. Here, we tested the role of deep-water access in enabling survival within a diverse tropical forest community in Panama using a novel data-model approach. We inversely estimated the effective rooting depth (ERD, as the average depth of water extraction), for 29 canopy species by linking diameter growth dynamics (1990–2015) to vapor pressure deficit, water potentials in the whole-soil column, and leaf hydraulic vulnerability curves. We validated ERD estimates against existing isotopic data of potential water-access depths. Across species, deeper ERD was associated with higher maximum stem hydraulic conductivity, greater vulnerability to xylem embolism, narrower safety margins, and lower mortality rates during extreme droughts over 35 years (1981–2015) among evergreen species. Species exposure to water stress declined with deeper ERD indicating that trees compensate for water stress-related mortality risk through deep-water access. The role of deep-water access in mitigating mortality of hydraulically-vulnerable trees has important implications for our predictive understanding of forest dynamics under current and future climates.
Original language | English |
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Pages (from-to) | 1798-1813 |
Number of pages | 16 |
Journal | New Phytologist |
Volume | 231 |
Issue number | 5 |
DOIs | |
State | Published - Sep 2021 |
Funding
This research was supported as part of the Next Generation Ecosystem Experiments-Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research. Funding also was provided to RC-T and SMM through an NSF grant (1137366). LR was deputed to Indo-French Cell for Water Sciences on an IRD Fellowship. An NSF grant to Smithsonian Institution’s ForestGEO (Dimensions 1046113) partially supported this work via RC-T and SMM. BTW was supported by the National Institute of Food and Agriculture, US Department of Agriculture, McIntire Stennis project under LAB94493. LS was supported by the National Science Foundation award 2017949. RAF was supported by the National Center for Atmospheric Research, which is funded by the National Science Foundation. MD was supported by the Carbon Mitigation Initiative at Princeton University. The BCI forest dynamics research project, founded by Stephen P. Hubbell and Robin B. Foster and sustained for many years by Richard Condit, is now managed by Rolando Pérez (RP), Suzanne Lao and Stuart Davies under the ForestGEO program of the Smithsonian Tropical Research in Panama. Numerous organizations have provided funding, principally the US National Science Foundation, and hundreds of field workers have contributed. Comments from editor Jarmila Pitterman and three anonymous reviewers helped improve and clarify this manuscript. This research was supported as part of the Next Generation Ecosystem Experiments‐Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research. Funding also was provided to RC‐T and SMM through an NSF grant (1137366). LR was deputed to Indo‐French Cell for Water Sciences on an IRD Fellowship. An NSF grant to Smithsonian Institution’s ForestGEO (Dimensions 1046113) partially supported this work via RC‐T and SMM. BTW was supported by the National Institute of Food and Agriculture, US Department of Agriculture, McIntire Stennis project under LAB94493. LS was supported by the National Science Foundation award 2017949. RAF was supported by the National Center for Atmospheric Research, which is funded by the National Science Foundation. MD was supported by the Carbon Mitigation Initiative at Princeton University. The BCI forest dynamics research project, founded by Stephen P. Hubbell and Robin B. Foster and sustained for many years by Richard Condit, is now managed by Rolando Pérez (RP), Suzanne Lao and Stuart Davies under the ForestGEO program of the Smithsonian Tropical Research in Panama. Numerous organizations have provided funding, principally the US National Science Foundation, and hundreds of field workers have contributed. Comments from editor Jarmila Pitterman and three anonymous reviewers helped improve and clarify this manuscript.
Funders | Funder number |
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Smithsonian Tropical Research in Panama | |
National Science Foundation | 2017949 |
Smithsonian Institution | |
U.S. Department of Energy | |
Directorate for Biological Sciences | 1046113, 1137366 |
U.S. Department of Agriculture | LAB94493 |
National Center for Atmospheric Research | |
National Institute of Food and Agriculture | |
Office of Science | |
Biological and Environmental Research | |
Princeton University |
Keywords
- deep-water access
- drought tolerance
- drought-induced mortality
- hydraulic vulnerability and safety margins
- hydrological droughts
- rooting depths
- safety-efficiency trade-off
- tropical forest