On underestimation of global vulnerability to tree mortality and forest die‐off from hotter drought in the Anthropocene

Ecosphere, Journal Year: 2015, Volume and Issue: 6(8), P. 1 - 55

Published: Aug. 1, 2015

Patterns, mechanisms, projections, and consequences of tree mortality associated broad‐scale forest die‐off due to drought accompanied by warmer temperatures—“hotter drought”, an emerging characteristic the Anthropocene—are focus rapidly expanding literature. Despite recent observational, experimental, modeling studies suggesting increased vulnerability trees hotter pests pathogens, substantial debate remains among research, management policy‐making communities regarding future risks. We summarize key mortality‐relevant findings, differentiating between those implying lesser versus greater levels vulnerability. Evidence includes benefits elevated [CO 2 ] water‐use efficiency; observed modeled increases in growth canopy greening; widespread woody‐plant biomass, density, extent; compensatory physiological, morphological, genetic mechanisms; dampening ecological feedbacks; potential mitigation management. In contrast, document more rapid under negative physiological responses accelerated biotic attacks. Additional evidence rising background rates; projected frequency, intensity, duration; limitations vegetation models such as inadequately represented processes; warming feedbacks from die‐off; wildfire synergies. Grouping these findings we identify ten contrasting perspectives that shape but have not been discussed collectively. also present a set global drivers are known with high confidence: (1) droughts eventually occur everywhere; (2) produces droughts; (3) atmospheric moisture demand nonlinearly temperature during drought; (4) can faster drought, consistent fundamental physiology; (5) shorter frequently than longer become lethal warming, increasing frequency nonlinearly; (6) happens relative intervals needed for recovery. These high‐confidence drivers, concert research supporting perspectives, support overall viewpoint globally. surmise is being discounted part difficulties predicting threshold extreme climate events. Given profound societal implications underestimating highlight urgent challenges management, communities.

Language: Английский

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Pervasive shifts in forest dynamics in a changing world

Science, Journal Year: 2020, Volume and Issue: 368(6494)

Published: May 28, 2020

Forest dynamics arise from the interplay of environmental drivers and disturbances with demographic processes recruitment, growth, mortality, subsequently driving biomass species composition. However, forest subsequent recovery are shifting global changes in climate land use, altering these dynamics. Changes drivers, disturbance regimes forcing forests toward younger, shorter stands. Rising carbon dioxide, acclimation, adaptation, migration can influence impacts. Recent developments Earth system models support increasingly realistic simulations vegetation In parallel, emerging remote sensing datasets promise qualitatively new more abundant data on underlying consequences for structure. When combined, advances hold improving scientific understanding demographics disturbances.

Language: Английский

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CTFS‐ForestGEO: a worldwide network monitoring forests in an era of global change

Global Change Biology, Journal Year: 2014, Volume and Issue: 21(2), P. 528 - 549

Published: Sept. 25, 2014

Global change is impacting forests worldwide, threatening biodiversity and ecosystem services including climate regulation. Understanding how respond critical to forest conservation protection. This review describes an international network of 59 long-term dynamics research sites (CTFS-ForestGEO) useful for characterizing responses global change. Within very large plots (median size 25 ha), all stems ≥ 1 cm diameter are identified species, mapped, regularly recensused according standardized protocols. CTFS-ForestGEO spans °S-61 °N latitude, generally representative the range bioclimatic, edaphic, topographic conditions experienced by only monitoring that applies a protocol each world's major biomes. Supplementary measurements at subsets provide additional information on plants, animals, environmental variables. experiencing multifaceted anthropogenic pressures warming (average 0.61 °C), changes in precipitation (up ± 30% change), atmospheric deposition nitrogen sulfur compounds 3.8 g N m(-2) yr(-1) 3.1 S yr(-1)), fragmentation surrounding landscape 88% reduced tree cover within 5 km). The broad suite made makes it possible investigate complex ways which dynamics. Ongoing across yielding insights into why changing, continued will vital contributions understanding worldwide diversity era

Language: Английский

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Wildfire-Driven Forest Conversion in Western North American Landscapes

BioScience, Journal Year: 2020, Volume and Issue: 70(8), P. 659 - 673

Published: May 18, 2020

Changing disturbance regimes and climate can overcome forest ecosystem resilience. Following high-severity fire, recovery may be compromised by lack of tree seed sources, warmer drier postfire climate, or short-interval reburning. A potential outcome the loss resilience is conversion prefire to a different type nonforest vegetation. Conversion implies major, extensive, enduring changes in dominant species, life forms, functions, with impacts on services. In present article, we synthesize growing body evidence fire-driven our understanding its causes across western North America. We assess capacity predict highlight important uncertainties. Increasing vulnerability changing fire activity compels shifts management approaches, propose key themes for applied research coproduced scientists managers support decision-making an era when not return.

Language: Английский

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A nationwide annual characterization of 25 years of forest disturbance and recovery for Canada using Landsat time series

Remote Sensing of Environment, Journal Year: 2017, Volume and Issue: 194, P. 303 - 321

Published: April 8, 2017

In the context of complex demands on forest resources and climate change, synoptic spatially-explicit baseline data characterizing national trends in disturbance subsequent return vegetation (and eventual to forest) are increasingly required. Time series analyses remotely sensed enable retrospective generation depicting both recovery, enabling a more holistic examination dynamics. this research, we utilize outputs Composite2Change, or C2C, algorithm that leverages extensive Landsat archive produce annual, gap-free, surface reflectance composites date label types characterize recovery over > 650 million ha Canada's forested ecosystems. From 1985 2010, 57.5 Mha 10.75% net ecosystem area (exclusive water) were disturbed by either wildfire harvest, representing an annual rate approximately 0.43% per year. Wildfire accounted for 2.5 times than harvest. On average, 1.6 annually had greater inter-annual variability with standard deviation 1.1 Mha, compared 0.65 harvesting (σ = 0.1 Mha). Herein, defined longer-term measure spectral (the number years it took pixel attain 80% its pre-disturbance Normalized Burn Ratio NBR value), which indicated harvested areas recovering consistently time relative wildfire, 78.6% requiring ≤ 10 recover, only 35.5% areas. A shorter-term (5-year) also based NBR, returned rapidly areas; however, when magnitude was incorporated into metric, typically larger variable areas, found be average short-term. Overall, < 1% harvest identified as non-recovering all three measures used our analysis. Regionally, largely echoed at level, although amounts rates varied ecozone. provide opportunity scale, type ecozone, spatially explicit manner level spatial detail is relevant management science.

Language: Английский

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Ghosts of the past: how drought legacy effects shape forest functioning and carbon cycling

Ecology Letters, Journal Year: 2020, Volume and Issue: 23(5), P. 891 - 901

Published: March 10, 2020

Multi-year lags in tree drought recovery, termed 'drought legacy effects', are important for understanding the impacts of on forest ecosystems, including carbon (C) cycle feedbacks to climate change. Despite ubiquity large uncertainties remain regarding mechanistic basis effects and their importance C cycle. In this review, we identify approaches used study effects, from rings whole forests. We then discuss key knowledge gaps pertaining causes how various mechanisms that may contribute these recovery could have contrasting implications Furthermore, conduct a novel data synthesis find differ drastically both size length across US depending if they identified versus gross primary productivity. Finally, highlight promising future research improve our capacity model predict impact health. emphasise holistic view - tissues forests will advance stimulate efforts investigate via experimental, observational modelling approaches.

Language: Английский

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Viewing forests through the lens of complex systems science

Ecosphere, Journal Year: 2014, Volume and Issue: 5(1), P. 1 - 23

Published: Jan. 1, 2014

Complex systems science provides a transdisciplinary framework to study characterized by (1) heterogeneity, (2) hierarchy, (3) self‐organization, (4) openness, (5) adaptation, (6) memory, (7) non‐linearity, and (8) uncertainty. thinking has inspired both theory applied strategies for improving ecosystem resilience adaptability, but applications in forest ecology management are just beginning emerge. We review the properties of complex using four well‐studied biomes (temperate, boreal, tropical Mediterranean) as examples. The lens yields insights into facets structure dynamics that facilitate comparisons among ecosystems. These share main differ specific ecological properties, disturbance regimes, human uses. show how this approach can help scientists managers conceptualize forests integrated social‐ecological provide concrete examples manage adaptive systems.

Language: Английский

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Protecting irrecoverable carbon in Earth’s ecosystems

Nature Climate Change, Journal Year: 2020, Volume and Issue: 10(4), P. 287 - 295

Published: March 31, 2020

Language: Английский

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Precipitation mediates the effect of human disturbance on the Brazilian Caatinga vegetation

Journal of Ecology, Journal Year: 2016, Volume and Issue: 105(3), P. 828 - 838

Published: Nov. 24, 2016

Summary Seasonally dry tropical forests ( SDTF s) are one of the most threatened world‐wide. These species‐rich not only cope with several acute (e.g. forest loss) and chronic overgrazing firewood extraction) human disturbances but also climate change longer more severe droughts); yet, isolated combined effects on vegetation poorly known. Given environmental filter imposed by drought in s, composition structure is expected to be strongly associated annual precipitation, thus may depend precipitation (i.e. interacting effect). We tested these hypotheses Brazilian Caatinga – a disturbances. evaluated (both additive multiplicative) effect disturbance index (landscape cover) diversity, stem density, evenness, taxonomic above‐ground biomass adult trees shrubs across 19 0·1‐ha plots distributed along gradients. recorded 5541 stems from 129 species. Precipitation showed stronger (positive) species diversity than and, as expected, depended (interacting effect): that is, (especially number rare species) was negatively related loss positively wetter sites, whereas drier weakly cover, disturbance. Contrary community density were all predictors. Synthesis . appears strong determining distribution water‐demanding plant Chronic (high‐productive) favour increasing ecosystem heterogeneity (intermediate hypothesis). Yet, biodiversity costs higher (low‐productive) forests; there co‐limitation forests. Overall, our findings indicate rapid climatic changes region will probably have negative this seasonally forest.

Language: Английский

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Fostering natural forest regeneration on former agricultural land through economic and policy interventions

Environmental Research Letters, Journal Year: 2020, Volume and Issue: 15(4), P. 043002 - 043002

Published: Feb. 25, 2020

Abstract Under suitable conditions, deforested land used for agricultural crops or pastures can revert to forest through the assisted unassisted process of natural regeneration. These naturally regenerating forests conserve biodiversity, provide a wide array ecosystem goods and services, support rural economies livelihoods. Based on studies in tropical temperate ecosystems, we summarize cases where regeneration is occurring landscapes around world identify socio-ecological factors that favor its development affect qualities, outcomes persistence. We describe how economic policy context creates barriers development, persistence, management forests, including perverse policies intended enhance protection native forests. conclude with recommendations specific interventions at local, national, global scales promote sustainable regrowth former while strengthening communities economies.

Language: Английский

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