Meta-analysis reveals that hydraulic traits explain cross-species patterns of drought-induced tree mortality across the globe

Proceedings of the National Academy of Sciences, Journal Year: 2016, Volume and Issue: 113(18), P. 5024 - 5029

Published: April 18, 2016

Significance Predicting the impacts of climate extremes on plant communities is a central challenge in ecology. Physiological traits may improve prediction drought forests globally. We perform meta-analysis across 33 studies that span all forested biomes and find that, among examined traits, hydraulic explain cross-species patterns mortality from drought. Gymnosperm angiosperm was associated with different giving insight into relative weights mechanisms prediction. Our results provide foundation for more mechanistic predictions drought-induced tree Earth’s diverse forests.

Language: Английский

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Hydraulic diversity of forests regulates ecosystem resilience during drought

Nature, Journal Year: 2018, Volume and Issue: 561(7724), P. 538 - 541

Published: Sept. 18, 2018

Language: Английский

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Drivers and mechanisms of tree mortality in moist tropical forests

New Phytologist, Journal Year: 2018, Volume and Issue: 219(3), P. 851 - 869

Published: Feb. 16, 2018

Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework testable hypotheses drivers, mechanisms and interactions that may underlie rates, identify next steps for improved understanding reduced prediction. Increasing are associated rising temperature vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases stand thinning or acceleration trees reaching larger, more vulnerable heights. The majority these drivers kill part through starvation hydraulic failure. relative importance each driver is unknown. High species diversity buffer MTFs against large-scale but recent expected trends give reason concern within MTFs. Models advancing representation hydraulics, demography, require empirical most common their subsequent mechanisms. We outline critical datasets model developments required test underlying causes improve prediction future under climate change. Contents Summary 852 I. Introduction II. Amazon Basin 854 III. Global regional 855 IV. On coupling 859 V. Mitigating factors promote survival VI. ESM simulations VII. Next 860 VIII. Conclusions 863 Acknowledgements ORCID References

Language: Английский

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Research frontiers for improving our understanding of drought‐induced tree and forest mortality

New Phytologist, Journal Year: 2018, Volume and Issue: 218(1), P. 15 - 28

Published: Feb. 28, 2018

Summary Accumulating evidence highlights increased mortality risks for trees during severe drought, particularly under warmer temperatures and increasing vapour pressure deficit ( VPD ). Resulting forest die‐off events have consequences ecosystem services, biophysical biogeochemical land–atmosphere processes. Despite advances in monitoring, modelling experimental studies of the causes tree death from individual to global scale, a general mechanistic understanding realistic predictions drought future climate conditions are still lacking. We update map present roadmap more holistic across scales. highlight priority research frontiers that promote: (1) new avenues on key ecophysiological responses drought; (2) scaling tree/plot level region; (3) improvements risk based both empirical insights; (4) monitoring network mortality. In light recent anticipated large such agenda is timely needed achieve scientific drought‐induced The implementation sustainable will require support by stakeholders political authorities at international level.

Language: Английский

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Plant xylem hydraulics: What we understand, current research, and future challenges

Journal of Integrative Plant Biology, Journal Year: 2017, Volume and Issue: 59(6), P. 356 - 389

Published: March 14, 2017

Herein we review the current state-of-the-art of plant hydraulics in context physiology, ecology, and evolution, focusing on future research opportunities. We explain physics water transport plants limits this system, highlighting relationships between xylem structure function. describe great variety techniques existing for evaluating resistance to cavitation. address several methodological issues their connection with debates conduit refilling exponentially shaped vulnerability curves. analyze trade-offs safety efficiency. also stress how little information is available molecular biology cavitation potential role aquaporins refilling. Finally, draw attention hydraulic traits can be used modeling stomatal responses environmental variables climate change, including drought mortality.

Language: Английский

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What plant hydraulics can tell us about responses to climate‐change droughts

New Phytologist, Journal Year: 2015, Volume and Issue: 207(1), P. 14 - 27

Published: March 13, 2015

Summary Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard anticipate because canopy transpiration diffusive conductance ( G ) respond drying soil vapor pressure deficit D complex ways. A growing database of hydraulic traits, combined with a parsimonious theory tree water transport its regulation, may improve predictions at‐risk vegetation. The uses the physics flow through xylem quantify how supply drought ceases by failure. This ‘supply function’ is used predict ‘loss assuming that stomatal regulation exploits capacity while avoiding Supply–loss incorporates root distribution, redistribution, cavitation vulnerability, reversal. efficiently defines , soil, vulnerability. Driving climate predicts drought‐induced loss plant k ), carbon assimilation, productivity. Data lead ‘chronic stress hypothesis’ wherein > 60% increases mortality multiple mechanisms. climatic conditions push over this risk threshold. theory's simplicity predictive power encourage testing application large‐scale modeling. Contents 14 I. Introduction II. function 15 III. 17 IV. General properties supply–loss 19 V. Variations on theme VI. Predicting 21 VII. Implications for mortality: chronic hypothesis 22 VIII. Conclusion 24 Acknowledgements References

Language: Английский

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Implementing Plant Hydraulics in the Community Land Model, Version 5

Journal of Advances in Modeling Earth Systems, Journal Year: 2019, Volume and Issue: 11(2), P. 485 - 513

Published: Jan. 31, 2019

Abstract Version 5 of the Community Land Model (CLM5) introduces plant hydraulic stress (PHS) configuration vegetation water use, which is described and compared with corresponding parameterization from CLM4.5. PHS updates root uptake to better reflect theory, advancing physical basis model. The new prognostic potential, modeled at root, stem, leaf levels. Leaf potential replaces soil as for stomatal conductance stress, used implement uptake, replacing a transpiration partitioning function. Point simulations tropical forest site (Caxiuanã, Brazil) under ambient conditions partial precipitation exclusion highlight differences between previous CLM implementation. description simulation results are contextualized list benefits limitations model formulation, including hypotheses that were not testable in versions Key include reductions moisture biases relative control both conditions, correcting excessive dry season implements gradient allows redistribution compensatory utilizing larger portion column buffer shortfalls precipitation. structure, bases on could have significant implications vegetation‐climate feedbacks, increased sensitivity photosynthesis atmospheric vapor pressure deficit.

Language: Английский

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Impacts of droughts on the growth resilience of Northern Hemisphere forests

Global Ecology and Biogeography, Journal Year: 2016, Volume and Issue: 26(2), P. 166 - 176

Published: Sept. 30, 2016

Abstract Aim The intensity and frequency of drought have increased considerably during recent decades in some Northern Hemisphere forested areas, future climate warming could further magnify stress. We quantify how forests resist events recover after them, i.e. we determine their growth resilience. Location North America Europe. Methods use a large tree‐ring database to study influences forest selected 775 width chronologies studied the occurrence years with extremely dry conditions (low soil moisture and/or high evaporative stress; hereafter ‘drought’) these forests. For each calculated three indices that represent different components resilience drought: resistance ( Rt ), recovery Rc ) Rs ). related variation geographical, topographic, climatic ecological from region. Results were interrelated. Resistance negatively related, both positively nonlinearly Drought latitude, slope, whereas decreased summer normalized difference vegetation index. elevation moisture. Temperate broadleaf wet regions showed greater (e.g. north‐eastern USA, central Europe) while conifer semi‐arid south‐western southern presented recovery. Main conclusions geographical patterns confirm existence strategies among cope droughts, depending on biome, tree species prevailing conditions. Geographical availability tend override species‐specific responses drought.

Language: Английский

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Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

Geoscientific model development, Journal Year: 2016, Volume and Issue: 9(11), P. 4227 - 4255

Published: Nov. 24, 2016

Abstract. Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed forests. We developed a continuous porous media approach modeling plant hydraulics which all parameters constitutive equations are biologically interpretable and measurable (e.g., turgor loss point πtlp, bulk elastic modulus ε, capacitance Cft, xylem conductivity ks,max, potential at 50 % for both (P50,x) stomata (P50,gs), leaf : sapwood area ratio Al As). embedded this model within trait simulator (TFS) that light environments individual trees their upper boundary conditions (transpiration), as well providing means parameterizing among individuals. synthesized literature existing databases parameterize function stem traits, including wood density (WD), mass per (LMA), photosynthetic capacity (Amax), evaluated coupled (called TFS v.1-Hydro) predictions, against diurnal seasonal variability stand-scaled sap flux. Our synthesis revealed coordination statistically significant relationships most with more easily measured traits. Using informative empirical trait–trait derived from synthesis, v.1-Hydro successfully captured due increasing size environment, representation architecture exerting primary secondary controls, respectively, fidelity predictions. The made substantial improvements simulations total transpiration. Remaining uncertainties limitations paradigm highlighted.

Language: Английский

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Will seasonally dry tropical forests be sensitive or resistant to future changes in rainfall regimes?

Environmental Research Letters, Journal Year: 2017, Volume and Issue: 12(2), P. 023001 - 023001

Published: Jan. 13, 2017

Seasonally dry tropical forests (SDTF) are located in regions with alternating wet and seasons, seasons that last several months or more. By the end of 21st century, climate models predict substantial changes rainfall regimes across these regions, but little is known about how individuals, species, communities SDTF will cope hotter, drier conditions predicted by models. In this review, we explore different scenarios may result ecological drought through lens two alternative hypotheses: 1) be sensitive to because they already limited water close climatic thresholds, 2) resistant/resilient intra- inter-annual adapted predictable, seasonal drought. our review literature spans microbial ecosystem processes, a majority available studies suggests increasing frequency intensity droughts likely alter species distributions processes. Though conclude altered regimes, many gaps remain. Future research should focus on geographically comparative well-replicated experiments can provide empirical evidence improve simulation used forecast responses future change at coarser spatial temporal scales.

Language: Английский

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