A first assessment of the impact of the extreme 2018 summer drought on Central European forests

Basic and Applied Ecology, Journal Year: 2020, Volume and Issue: 45, P. 86 - 103

Published: April 29, 2020

In 2018, Central Europe experienced one of the most severe and long-lasting summer drought heat wave ever recorded. Before 2003 millennial was often invoked as example a "hotter drought", classified event in for last 500 years. First insights now confirm that 2018 climatically more extreme had greater impact on forest ecosystems Austria, Germany Switzerland than drought. Across this region, mean growing season air temperature from April to October 3.3°C above long-term average, 1.2°C warmer 2003. Here, we present first assessment heatwave European forests. response event, ecologically economically important tree species temperate forests showed signs stress. These symptoms included exceptionally low foliar water potentials crossing threshold xylem hydraulic failure many observations widespread leaf discoloration premature shedding. As result stress, caused unprecedented drought-induced mortality throughout region. Moreover, unexpectedly strong drought-legacy effects were detected 2019. This implies physiological recovery trees impaired after leaving them highly vulnerable secondary impacts such insect or fungal pathogen attacks. consequence, triggered by events is likely continue several Our indicates common are waves previously thought. occur frequently with progression climate change, might approach point substantial ecological economic transition. also highlights urgent need pan-European ground-based monitoring network suited track individual mortality, supported remote sensing products high spatial temporal resolution track, analyse forecast these transitions.

Language: Английский

---

Mechanisms of woody-plant mortality under rising drought, CO2 and vapour pressure deficit

Nature Reviews Earth & Environment, Journal Year: 2022, Volume and Issue: 3(5), P. 294 - 308

Published: March 29, 2022

Language: Английский

---

Plants’ Physio-Biochemical and Phyto-Hormonal Responses to Alleviate the Adverse Effects of Drought Stress: A Comprehensive Review

Plants, Journal Year: 2022, Volume and Issue: 11(13), P. 1620 - 1620

Published: June 21, 2022

Water, a necessary component of cell protoplasm, plays an essential role in supporting life on Earth; nevertheless, extreme changes climatic conditions limit water availability, causing numerous issues, such as the current water-scarce regimes many regions biome. This review aims to collect data from various published studies literature understand and critically analyze plants’ morphological, growth, yield, physio-biochemical responses drought stress their potential modulate nullify damaging effects via activating natural physiological biochemical mechanisms. In addition, described breakthroughs understanding how plant hormones influence phytohormonal interaction through signaling under regimes. The information for this was systematically gathered different global search engines scientific databases Science Direct, including Google Scholar, Web Science, related studies, books, articles. Drought is significant obstacle meeting food demand world’s constantly growing population. Plants cope with cellular osmotic potential, activation defense systems form antioxidant enzymes accumulation osmolytes proteins, proline, glycine betaine, phenolic compounds, soluble sugars. Phytohormones developmental processes networks, which aid acclimating plants biotic abiotic challenges and, consequently, survival. Significant progress has been made jasmonates, salicylic acid, ethylene identifying important components roles stress. Other hormones, abscisic auxin, gibberellic brassinosteroids, peptide have linked pathways ways.

Language: Английский

---

Increasing sensitivity of dryland vegetation greenness to precipitation due to rising atmospheric CO2

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Aug. 19, 2022

Water availability plays a critical role in shaping terrestrial ecosystems, particularly low- and mid-latitude regions. The sensitivity of vegetation growth to precipitation strongly regulates global dynamics their responses drought, yet changes response climate change remain poorly understood. Here we use long-term satellite observations combined with dynamic statistical learning approach examine the greenness over past four decades. We observe robust increase (0.624% yr−1) for drylands, decrease (−0.618% wet Using model simulations, show that contrasting trends between dry regions are caused by elevated atmospheric CO2 (eCO2). eCO2 universally decreases reducing leaf-level transpiration, However, this transpiration reduction is overridden at canopy scale large proportional leaf area. increased drylands implies potential ecosystem stability greater impacts droughts these vulnerable ecosystems under continued change. Changes may be hydroclimate dependent. authors reveal vs. wetter last 4 decades identify as major contributing factor.

Language: Английский

---

Tree effects on urban microclimate: Diurnal, seasonal, and climatic temperature differences explained by separating radiation, evapotranspiration, and roughness effects

Urban forestry & urban greening, Journal Year: 2020, Volume and Issue: 58, P. 126970 - 126970

Published: Dec. 28, 2020

Increasing urban tree cover is an often proposed mitigation strategy against heat as trees are expected to cool cities through evapotranspiration and shade provision. However, also modify wind flow aerodynamic roughness, which can potentially limit dissipation. Existing studies show a varying cooling potential of in different climates times the day. These differences so far not systematically explained partitioning individual effects challenging impossible observations alone. Here, we conduct numerical experiments removing adding radiation, evapotranspiration, roughness caused by using mechanistic ecohydrological model. Simulations presented for four (Phoenix, Singapore, Melbourne, Zurich) considering seasonal diurnal cycles air surface temperatures. Results that well-watered alone decrease local 2 m temperature at maximum 3.1– 5.8 °C during summer. Further prevented stomatal closure peak temperatures high vapour pressure deficits transpiration. While shading reduces temperatures, interaction non-transpiring with radiation increase up 1.6 – 2.1 certain hours day scale, thus partially counteracting evapotranspirative effect. Furthermore, analysed scenarios, do account blockage effects, lead inhibits turbulent energy exchange increases daytime. At night, single variable likely due atmospheric stability within canyon. results explain reported diurnal, climatic trees, guide future field campaigns, planning strategies, species selection aimed improving microclimate greenery.

Language: Английский

---

A stomatal safety-efficiency trade-off constrains responses to leaf dehydration

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: July 30, 2019

Stomata, the microvalves on leaf surfaces, exert major influences across scales, from plant growth and productivity to global carbon water cycling. Stomatal opening enables photosynthesis, use, whereas survival of drought depends stomatal closure. Here we report that function is constrained by a safety-efficiency trade-off, such species with greater conductance under high availability (gmax) show sensitivity closure during dehydration, i.e., higher potential at which reduced 50% (Ψgs50). The gmax - Ψgs50 trade-off its mechanistic basis supported experiments leaves California woody species, in analyses previous studies responses diverse flowering around world. Linking two fundamental key roles stomata-the enabling gas exchange, first defense against drought-this constrains rates use leaves, impacts ecosystems.

Language: Английский

---

Declining root water transport drives stomatal closure in olive under moderate water stress

New Phytologist, Journal Year: 2019, Volume and Issue: 225(1), P. 126 - 134

Published: Sept. 9, 2019

Summary Efficient water transport from soil to leaves sustains stomatal opening and steady‐state photosynthesis. The aboveground portion of this pathway is well‐described, yet the roots their connection with are still poorly understood due technical limitations. Here we used a novel rehydration technique investigate changes in hydraulic between within plant body as individual olive plants were subjected range stresses. Whole root resistance (including radial xylem soil–root interface) constituted 81% whole‐plant unstressed plants, increasing > 95% under moderate level stress. decline whole conductance occurred parallel closure contributed significantly reduction canopy according model. Our results demonstrate that losses conductance, mainly disconnection during stress profound sufficient induce before cavitation occurs. Future studies will determine whether core regulatory role hydraulics exists more generally among diverse species.

Language: Английский

---

Rapid hydraulic collapse as cause of drought-induced mortality in conifers

Proceedings of the National Academy of Sciences, Journal Year: 2021, Volume and Issue: 118(16)

Published: April 12, 2021

Understanding the vulnerability of trees to drought-induced mortality is key predicting fate forests in a future climate with more frequent and intense droughts, although underlying mechanisms are difficult study adult trees. Here, we explored dynamic changes water relations limits hydraulic function dying adults Norway spruce (Picea abies L.) during progression record-breaking 2018 Central European drought. In on trajectory mortality, observed rapid, nonlinear declines xylem pressure that commenced at early onset cavitation caused complete loss conductance within very short time. We also severe depletions nonstructural carbohydrates, though carbon starvation could be ruled out as cause tree death, both surviving showed these metabolic limitations. Our observations provide striking field-based evidence for fast dehydration collapse spruce. The decline suggests considering temporal dynamics critical death. system time demonstrates can rapidly pushed zone safety summary, our findings point toward higher risk than previously assumed, which line current reports unprecedented levels this major species.

Language: Английский

---

Underappreciated plant vulnerabilities to heat waves

New Phytologist, Journal Year: 2021, Volume and Issue: 231(1), P. 32 - 39

Published: March 17, 2021

With climate change, heat waves are becoming increasingly frequent, intense and broader in spatial extent. However, while the lethal effects of on humans well documented, impacts flora less understood, perhaps except for crops. We summarize recent findings related to wave including: sublethal at leaf plant scales, secondary ecosystem effects, more complex such as increased frequency across all seasons, interactions with other disturbances. propose generalizable practical trials quantify critical bounding conditions vulnerability waves. Collectively, vulnerabilities appear be underappreciated understudied, particularly respect understanding driven die-off tipping points.

Language: Английский

---

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Jan. 10, 2022

Abstract Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These remain poorly understood at the tree species level across large spatial scales. Here, we investigate effects of record-breaking 2018 European heatwave growth water status using a collection high-temporal resolution dendrometer data from 21 53 sites. Relative to two preceding years, annual stem was not consistently reduced by but stems experienced twice temporary shrinkage due depletion reserves. Conifer were less capable rehydrating overnight than broadleaves gradients soil atmospheric drought, suggesting resilience toward transient stress. In particular, Norway spruce Scots pine extensive dehydration. Our high-resolution network suitable disentangle severe desiccation large-spatial scales in situ, provided insights which may be more vulnerable climate extremes.

Language: Английский

---