Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system

Photochemical & Photobiological Sciences, Journal Year: 2023, Volume and Issue: 22(5), P. 1049 - 1091

Published: Feb. 1, 2023

Terrestrial organisms and ecosystems are being exposed to new rapidly changing combinations of solar UV radiation other environmental factors because ongoing changes in stratospheric ozone climate. In this Quadrennial Assessment, we examine the interactive effects ozone, climate on terrestrial biogeochemical cycles context Montreal Protocol. We specifically assess organisms, agriculture food supply, biodiversity, ecosystem services feedbacks system. Emphasis is placed role extreme events altering exposure potential biodiversity. also address responses plants increased temporal variability radiation, change (e.g. drought, temperature) crops, driving breakdown organic matter from dead plant material (i.e. litter) biocides (pesticides herbicides). Our assessment indicates that interact various ways affect structure function ecosystems, by protecting layer, Protocol continues play a vital maintaining healthy, diverse land sustain life Earth. Furthermore, its Kigali Amendment mitigating some negative consequences limiting emissions greenhouse gases carbon sequestration vegetation pool.

Language: Английский

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Uncertainty in US forest carbon storage potential due to climate risks

Nature Geoscience, Journal Year: 2023, Volume and Issue: 16(5), P. 422 - 429

Published: April 6, 2023

Language: Английский

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Forest restoration and fuels reduction work: Different pathways for achieving success in the Sierra Nevada

Ecological Applications, Journal Year: 2023, Volume and Issue: 34(2)

Published: Nov. 10, 2023

Abstract Fire suppression and past selective logging of large trees have fundamentally changed frequent‐fire‐adapted forests in California. The culmination these changes produced that are vulnerable to catastrophic change by wildfire, drought, bark beetles, with climate exacerbating this vulnerability. Management options available address problem include mechanical treatments (Mech), prescribed fire (Fire), or combinations (Mech + Fire). We quantify forest structure composition, fuel accumulation, modeled behavior, intertree competition, economics from a 20‐year restoration study the northern Sierra Nevada. All three active (Fire, Mech, Mech Fire) conditions were much more resistant wildfire than untreated control. included lowest surface duff loads hazards. low hazards beginning 7 years after initial treatment had lower tree growth controls. only competition somewhat similar historical California mixed‐conifer was Fire, indicating stands under would likely be resilient enhanced stressors. While reduced hazard reintroduced fundamental ecosystem process, it done at net cost landowner. Using mastication thinning resulted positive revenues also relatively strong as an investment reducing hazard. represents compromise between desire sustain financial feasibility reintroduce fire. One key component long‐term conservation will continued maintain improve restoration. Many Indigenous people speak “active stewardship” one principles land management aligns well need for increased western US forests. If we do not use knowledge 20+ research longer tradition cultural practices knowledge, frequent‐fire continue degraded lost.

Language: Английский

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Enhancing wildfire mapping accuracy using mono-temporal Sentinel-2 data: A novel approach through qualitative and quantitative feature selection with explainable AI

Ecological Informatics, Journal Year: 2024, Volume and Issue: 81, P. 102601 - 102601

Published: April 16, 2024

Accurate wildfire severity mapping (WSM) is crucial in environmental damage assessment and recovery strategies. Machine learning (ML) remote sensing technologies are extensively integrated employed as powerful tools for WSM. However, the intricate nature of ML algorithms often leads to 'black box' systems, obscuring decision-making process significantly limiting stakeholders' ability comprehend basis predictions. This opacity hinders efforts enhance performance risks exacerbating overfitting. present study proposes an innovative WSM approach that incorporates qualitative quantitative feature selection techniques within Explainable AI (XAI) framework. The methodology aims precision provide insights into factors contributing model decisions, thereby increasing interpretability predictions streamlining models improve performance. To achieve this objective, we SHapley Additive exPlanations (SHAP)-Forward Stepwise Selection (FSS) method demonstrate its efficacy elucidating impacts predictors on algorithm performance, accuracy, designed Utilizing post-fire imagery from Sentinel-2 (S2), analyzed ten bands generate 225 unique spectral indices utilizing five different calculations: normalized, algebraic sum, difference, ratio, product forms. Combined with original S2 bands, resulted 235 potential classifications. A random forest was subsequently developed using these optimized through extensive hyperparameter tuning, achieving overall accuracy (OA) 0.917 a Kappa statistic 0.896. most influential were identified SHAP values, FSS narrowing them down 12 critical effective WSM, evidenced by stabilized OA values (0.904 0.881, respectively). Further validation ninefold spatial cross-validation technique demonstrated method's consistent across data partitions, ranging 0.705 0.894 0.607 0.867. By providing more accurate comprehensible XAI-based research contributes broader field monitoring disaster response, underscoring analysis models' capabilities.

Language: Английский

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Climate change and California’s terrestrial biodiversity

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(32)

Published: July 29, 2024

In this review and synthesis, we argue that California is an important test case for the nation world because terrestrial biodiversity very high, present anticipated threats to from climate change other interacting stressors are severe, innovative approaches protecting in context of being developed tested. We first salient dimensions California's physical, biological, human diversity. Next, examine four facets threat their sustainability these posed by change: direct impacts, illustrated a new analysis shifting diversity hotspots plants; interactive effects involving invasive species, land-use change, stressors; impacts changing fire regimes; land-based renewable energy development. recent policy responses each areas, representing attempts better protect while advancing adaptation mitigation. conclude ambitious 30 × Initiative its efforts harmonize conservation with development areas progress. Adapting traditional suppression-oriented policies reality regimes area which much progress remains be made.

Language: Английский

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Using remote sensing to quantify the additional climate benefits of California forest carbon offset projects

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(22), P. 6789 - 6806

Published: Sept. 12, 2022

Nature-based climate solutions are a vital component of many mitigation strategies, including California's, which aims to achieve carbon neutrality by 2045. Most offsets in California's cap-and-trade program come from improved forest management (IFM) projects. Since 2012, various landowners have set up IFM projects following the California Air Resources Board's protocol. As these approach their 10th year, we now opportunity assess effectiveness, identify best practices, and suggest improvements toward future protocol revisions. In this study, used remote sensing-based datasets evaluate trends harvest histories 37 California. Despite some current limitations biases, can be quantify accumulation rates offset project lands relative nearby similar "control" before after began. Five lines evidence that accumulated date has generally not been additional what might otherwise occurred: (1) most forests northwestern accumulating since at least mid-1980s continue accumulate carbon, whether enrolled or not; (2) were high large timber company initiation, suggesting they earning credits for recovery; (3) often located on with higher densities low-timber-value species; (4) yet increased enroll as projects, pre-enrollment levels; (5) decreased initiation. These patterns should robustly measure reward additionality. general, our framework geospatial analyses offers an important independent means effectiveness program, especially data products improving receive attention strategy.

Language: Английский

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Drivers of California’s changing wildfires: a state-of-the-knowledge synthesis

International Journal of Wildland Fire, Journal Year: 2023, Volume and Issue: 32(7), P. 1039 - 1058

Published: May 22, 2023

Over the past four decades, annual area burned has increased significantly in California and across western USA. This trend reflects a confluence of intersecting factors that affect wildfire regimes. It is correlated with increasing temperatures atmospheric vapour pressure deficit. Anthropogenic climate change driver behind much this change, addition to influencing other climate-related factors, such as compression winter wet season. These climatic trends associated increases fire activity are projected continue into future. Additionally, related suppression Indigenous use fire, aggressive and, some cases, changes logging practices or fuel management intensity, collectively have produced large build-ups vegetative fuels ecosystems. Human activities provide most common ignition source for California’s wildfires. Despite its human toll, provides range ecological benefits many Given diversity vegetation types regimes found state, addressing challenges will require multi-faceted locally targeted responses terms management, human-caused ignitions, building regulations restrictions, integrative urban ecosystem planning, collaboration Tribes support reinvigoration traditional burning

Language: Английский

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Low-intensity fires mitigate the risk of high-intensity wildfires in California’s forests

Science Advances, Journal Year: 2023, Volume and Issue: 9(45)

Published: Nov. 10, 2023

The increasing frequency of severe wildfires demands a shift in landscape management to mitigate their consequences. role managed, low-intensity fire as driver beneficial fuel treatment fire-adapted ecosystems has drawn interest both scientific and policy venues. Using synthetic control approach analyze 20 years satellite-based activity data across 124,186 square kilometers forests California, we provide evidence that fires substantially reduce the risk future high-intensity fires. In conifer forests, is reduced by 64.0% [95% confidence interval (CI): 41.2 77.9%] areas recently burned at low intensity relative comparable unburned areas, protective effects last for least 6 (lower bound one-sided 95% CI: years). These findings support transition from suppression restoration, through increased use prescribed fire, cultural burning, managed wildfire, presuppression precolonial regime California.

Language: Английский

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The magnitude and pace of photosynthetic recovery after wildfire in California ecosystems

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(15)

Published: April 3, 2023

Wildfire modifies the short- and long-term exchange of carbon between terrestrial ecosystems atmosphere, with impacts on ecosystem services such as uptake. Dry western US forests historically experienced low-intensity, frequent fires, patches across landscape occupying different points in fire-recovery trajectory. Contemporary perturbations, recent severe fires California, could shift historic stand-age distribution impact legacy uptake landscape. Here, we combine flux measurements gross primary production (GPP) chronosequence analysis using satellite remote sensing to investigate how last century California impacted dynamics fire-affected A GPP recovery trajectory curve more than five thousand forest since 1919 indicated that fire reduced by [Formula: see text] g C m[Formula: y[Formula: text]([Formula: text]) first year after fire, average prefire conditions y. The largest forested (n = 401) took two decades recover. Recent increases severity time have led nearly MMT CO[Formula: (3-y rolling mean) cumulative forgone due landscape, complicating challenge maintaining California's natural working lands a net sink. Understanding these changes is paramount weighing costs benefits associated fuels management for climate change mitigation.

Language: Английский

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Satellite detection of canopy-scale tree mortality and survival from California wildfires with spatio-temporal deep learning

Remote Sensing of Environment, Journal Year: 2023, Volume and Issue: 298, P. 113842 - 113842

Published: Oct. 12, 2023

Mapping forest disturbances is paramount to carbon monitoring, estimating environmental drivers, and developing strategies enhance resilience. Existing change products from Landsat Sentinel-2 have improved our understanding of large-scale disturbance patterns; however, their relatively coarse spatial resolution (10 30-m) leads the use mixed pixels which constrains application for detecting heterogeneous survival or mortality outcomes occurring at level individual trees canopies. PlanetScope multispectral imagery 3-m near-daily frequency offers new capabilities detect monitor diverse tree patterns following across landscapes. This research proposes a framework canopy-scale (3 × 3-m) tree/shrub using monthly time series. A 3D Spatio-Temporal Convolutional Neural Network (ST-CNN) deep learning model was designed fully utilize context temporal unique canopy As crucial component training robust scalable models, large set labels collected via semi-automatic workflow by combining pre-disturbance lidar crown segmentation post-disturbance aerial interpretation. We applied 15 wildfires in California 2018–2021. sampled 1,176 384 384-m scenes burned areas with pre-fire lidar, containing >1.8M shrub polygons labeled as dead alive wildfire. Evaluated an independent testing dataset, optimized ST-CNN detects representing accurately align observed/labeled data. Tree detection accuracy high stable Sierra Nevada North Coast Mountains ecoregions (user's = 83%–86%; producer's 81%–82%), but decreased slightly within sparser Central Foothills South 77%–81%; 58%–61%) often due confusion between mortality. Producer's increased height remained (>75%) on canopies taller than 11-m. Further, sensitivity analysis demonstrates performance benefits and/or convolutions architecture prediction. Lastly, we demonstrate scalability regional-scale all 2020 (∼1.6 Mha burn area). The wall-to-wall post-fire maps showed overall rate 58.8%, ranging 32% 94% among fires. trained provides ecologically detailed estimation composition (trees, shrubs, non-woody) (survival mortality) post-disturbance. These data will improve higher monitoring assessment impacts, allow better vulnerability, support management actions.

Language: Английский

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