共检索到 11

Wildfires, both natural and man-made, release and mobilize hazardous substances such as heavy metal(loids) (HM), which are known carcinogens. Following intense rainfall events, HM bound to soil organic matter are transported from the soil to surface water, resulting in water quality degradation. This study reviews the pollution status of HM in wildfire-affected soil and surface water, as well as their toxic effects on aquatic organisms and humans. The rate of HM release during wildfires depends on factors such as the type of tree burned and fire severity. The mobility of HM from soil to surface water is influenced by soil pH, organic matter content, rainfall intensity, and duration. The risk priority number (RPN) analysis indicates that both wildfire-affected soil and surface water require remediation to address HM contamination. HM concentrations in both soil and surface water decrease over time due to soil erosion, wind, storm events, and the depletion of burnt residues. The greatest percentage changes in HM concentrations in burned soils compared to unburned soils were observed for vanadium (340%), nickel (260%), and arsenic (110%). In surface water, the highest increases were seen for iron (740%), vanadium (530%), and aluminium (510%). Wildfire-affected water has been shown to cause toxic effects in aquatic organisms, including DNA damage, oxidative stress, and lipid peroxidation. The consumption of HMcontaminated water and fish poses significant health risks to humans. Therefore, post-fire monitoring of wildfireaffected areas is essential for designing treatment plants, assessing risks, and establishing maximum allowable HM concentrations in water.

期刊论文 2025-03-15 DOI: 10.1016/j.envpol.2025.125845 ISSN: 0269-7491

High-severity wildfires create heterogeneous patterns of vegetation across burned landscapes. While these spatial patterns are well-documented, less is known about the short- and long-term effects of large-scale high-severity wildfires on insect community assemblages and dynamics. Ants are bottom-up indicators of ecosystem health and function that are sensitive to disturbance and fill a variety of roles in their ecosystems, including altering soil chemistry, dispersing seeds, and serving as a key food resource for many species, including the federally endangered Jemez Mountain salamander (Plethodon neomexicanus). We examined the post-fire effects of the 2011 Las Conchas Wildfire on ant communities in the Valles Caldera National Preserve (Sandoval County, New Mexico, USA). We collected ants via pitfall traps in replicated burned and unburned sites across three habitats: ponderosa pine forests, mixed-conifer forests, and montane grassland. We analyzed trends in species richness, abundance, recruitment, loss, turnover, and composition over five sequential years of post-fire succession (2011-2015). Ant foraging assemblage was influenced by burn presence, season of sampling, and macrohabitat. We also found strong seasonal trends and decreases over time since fire in ant species richness and ant abundance. However, habitat and seasonal effects may be a stronger predictor of ant species richness than the presence of fire or post-fire successional patterns.

期刊论文 2024-12-01 DOI: 10.3390/conservation4040049

Postfire management actions are used to mitigate damage caused by wildfires. Salvage logging, often employed to restore ecosystem functions in burnt stands, plays an essential role in reducing economic losses and the burn severity of future wildfires. However, its ecological implications for soil functionality still need to be understood, especially in the Mediterranean basin, which is prone to erosion and desertification. This study aimed to investigate the effects of fire on (i) soil organic matter (SOM) quality and composition using differential scanning calorimetry-thermogravimetry (DSC-TG) and solid-state nuclear magnetic resonance (C-13 CPMAS NMR) and (ii) phosphorus (P) forms using solid-state( 31) P NMR spectroscopy in a wildfire that affected 3200 ha in southeastern Spain in July 2017. One year after the fire, we monitored four Pinus halepensis Mill. stand categories based on soil burn severity (SBS): unburnt, low SBS, high SBS and high SBS areas with salvage logging (n=36, nine plots per SBS level). We collected soil samples and analysed soil pH, SOM content and SOM quality, along with biological activity indicators (carbon biomass, basal respiration, beta-glucosidase, phosphatase activities) and P forms. We ran ANOVA statistical tests to identify significant differences in soil properties among SBS levels. We also established general linear regressions of thermo-recalcitrance values and aromaticity with biological soil quality indices to compare both techniques for detecting changes in SOM quality and composition. The results indicated that fire increased soil pH (up to 0.3), particularly in the plots with higher SBS levels. SOM decreased significantly with increasing SBS level (down to < 5 % at the high SBS level), with a shift from labile compounds (carbohydrates) to more recalcitrant ones (aromatics). Organic P forms were depleted, while orthophosphate levels rose, increasing the risk of irreversible fixation. This study also highlights that DSC-TG is a cost-effective technique for assessing SOM quality changes. Understanding these effects is essential for developing policies to conserve and restore fire- affected areas and to promote practices that enhance soil functionality and resilience.

期刊论文 2024-12-01 DOI: 10.1016/j.foreco.2024.122344 ISSN: 0378-1127

Burn severity maps are typically generated using spectral indices and used in classifying the spatial distribution of damage caused by fires. In densely vegetated forests, even when overstory crowns are severely affected by the high-intensity fire, the topsoil may not experience high temperatures which makes spectral indices inadequate for assessing soil burn severity. On the other hand, field observations of soil burn severity can be subjective. For this reason, horizon-based soil sampling and extensive soil testing (physical, hydrological, chemical, mineralogical, and mechanical properties) were conducted in this study. Statistical tests have been employed to identify the most representative soil parameters of soil burn severity in the area. The remote sensing data (differential spectral indices and land surface temperature), field observations, and site-specific burned soil data were combined through weighted overlay analysis in the Geographical Information System (GIS). Accordingly, an improved soil burn severity map for the area affected by a forest fire in Kavaklidere, Mugla, Turkiye was produced to show the post-fire soil erodibility potential. The findings of this study indicated that the effect of fire on soil properties was limited to the upper 0-4 cm of the soil profile with surface temperatures reaching a maximum of 300 degrees C for the high burn severity. The liquid limit, shear strength, organic matter, water repellency, and mean grain size were determined to be promising parameters to represent the soil burn severity. The map produced using the novel approach outperformed conventional burn severity maps. In addition, the high soil burn severity class can serve as a parameter to indicate erosion susceptibility after a wildfire.

期刊论文 2024-10-01 DOI: 10.1016/j.catena.2024.108302 ISSN: 0341-8162

. The berry borer is the most damaging insect pest of coffee worldwide, affecting both yield and quality. Due to its economic importance, the borer has been the subject of considerably research around the world, both to determine its biology, as well as to develop economically and environmentally viable control technologies. Much of the work has focused on biological control with parasitoids and entomopathogens. The objective of this study was to isolate, identify and evaluate strains of Beauveria bassiana native to the coffee growing areas of Nayarit against the coffee berry borer under field conditions. The strains were obtained from soil and coffee fruit samples from 15 coffee orchards and were evaluated in an organic coffee production orchard. In general, the strains of B. bassiana showed good performance against the coffee berry borer with effectiveness higher than 76%. In the region of study, if control measures are not applied, the percentages of infestation could reach up to 56%. Regional B. bassiana strains are considered an option for biological control of the coffee berry borer.

期刊论文 2024-09-01 DOI: 10.19136/era.a11n3.4148 ISSN: 2007-901X

Liquefaction of sub-soil is a phenomenon in which partially saturated or saturated loose cohesionless sub-soil, especially loose fine sand, significantly lose their strength and stiffness in response to applied stresses. It occurs generally during earthquake shakings because of the generation of surplus pore water pressure, causing it to lose its effective stress and act like a liquid. Essentially, prediction of the liquefaction severity accurately is very important for liquefaction-prone sites for different seismic conditions. All the structures that are constructed on sub-soil are susceptible to liquefaction and can get damaged as a result of earthquake ground motion. Since earthquakes are one of the most disastrous events, analysis for sub-soil needs to be conducted to understand the soil behavior and its stability against liquefaction at different sites. There are several simplified techniques to assess liquefaction potential on the basis of standard penetration test (SPT), cone penetration test (CPT), and shear wave velocity (Vs) test. In this paper, simplified liquefaction analysis has been carried out based on SPT data for 10 sites in Bahraich District situated in Uttar Pradesh. Liquefaction potential index (LPI) has been calculated and the level of liquefaction severity is classified. It was observed that out of 10 site that have been evaluated 5 had moderate to high severity; while, the remaining 5 sites had high to very high severity. The classification helped in preliminary comprehension of the liquefaction susceptibility of the sites selected for construction.

期刊论文 2024-08-19 DOI: 10.1007/s40098-024-01046-w ISSN: 0971-9555

Wildfire strongly influences permafrost environment and soil organic carbon (SOC) pool. In this study, we reviewed the effects of fire severity, time after a fire, and frequency on SOC in boreal permafrost regions. This review highlighted several key points: the effect of wildfires on SOC increased with an increase of fire severity, and the amount of vegetation returned and surface organic matter replenished was less in a short term, which resulted in a significantly lower SOC content compared to that of before the fire. Within a short period after fire, the SOC in near-surface permafrost and the active layer decreased significantly due to the loss of above ground biomass, permafrost thaw, and increased microbial decomposition; as the years pass after a fire, the SOC gradually accumulates due to the contributions of litter layer accumulation and rooting systems from different stages of succession. The increase in fire frequency accelerated permafrost thawing and the formation of thermokarst, resulting in the rapid release of a large amount of soil carbon and reduced SOC storage. Therefore, the study on the effects of wildfires on SOC in the boreal permafrost region is of great significance to understanding and quantifying the carbon balance of the ecosystem.

期刊论文 2024-08-09 DOI: 10.1002/ppp.2247 ISSN: 1045-6740

Liquefaction has been known as a phenomenon in which the shear strength and stiffness of saturated soil are reduced by the generation of pore water pressure under earthquake loading. Consequently, liquefaction-induced settlement can result in severe damage including building cracks or slope failure, which pose a threat to human lives and properties. In the current Vietnamese standard TCVN 9386:2012, liquefaction potential hazard is often evaluated using the simplified method, which solely identifies the areas with a high risk of liquefaction. Prediction of Safety Factor (FS), Settlement (S), Liquefaction Potential Index (LPI), and Liquefaction Severity Number (LSN) has not received sufficient attention to a completeness standard. This study assesses the liquefaction of the site at Ho Chi Minh City, Vietnam by using four conventional methods: the simplified procedure, linear equivalent analysis, loosely-coupled effective stress analysis, and fully-coupled effective stress analysis based on standard penetration test (SPT) data in Ho Chi Minh Metropolitan City. A class of seismic events that are compatible with the design response spectrum in the Vietnamese standard TCVN 9386:2012 is used as input ground motion at the bedrock. According to the results of different methods, maps of ground settlement, LPI, and LSN are proposed as useful references for construction works on such soils, which may have a high potential for liquefaction and subsidence.

期刊论文 2024-06-01 DOI: 10.1007/s12303-024-0006-4 ISSN: 1226-4806

Several studies have documented a close relationship between forest fires and the instability of the soil-vegetation system. Furthermore, repeated wildfires, especially characterized by extreme severity and intensity, can induce hydrological and geomorphological effects that persist over several years, e.g., the temporary erosion rate intensification and the susceptibility increase of most significant downslope soil movement. This study analyzes the close relationship between wildfires and soil instability by examining the mega-fire in July 2021 in the Montiferru - Planargia region (Sardinia, Central Mediterranean). The proposed multiscalar methodology provides management and plan indications to mitigate potential damages caused by extreme wildfire, especially in areas with high susceptibility from a hydrogeological perspective, using physical models supported by open geodata in a GIS-based workflow.

期刊论文 2024-01-01 DOI: 10.1007/978-3-031-59925-5_2 ISSN: 1865-0929

Wildfires strongly regulate carbon (C) cycling and storage in boreal forests and account for almost 10% of global fire C emissions. However, the anticipated effects of climate change on fire regimes may destabilize current C-climate feedbacks and switch the systems to new stability domains. Since most of these forests are located in upland soils where permafrost is widespread, the expected climate warming and drying combined with more active fires may alter the greenhouse gas (GHG) budgets of boreal forests and trigger unprecedented changes in the global C balance. Therefore, a better understanding of the effects of fires on the various spatial and temporal patterns of GHG fluxes of different physical environments (permafrost and nonpermafrost soils) is fundamental to an understanding of the role played by fire in future climate feedbacks. While large amounts of C are released during fires, postfire GHG fluxes play an important role in boreal C budgets over the short and long term. The timescale over which the vegetation cover regenerates seems to drive the recovery of C emissions after both low-and high-severity fires, regardless of fire-induced changes in soil decomposition. In soils underlain by permafrost, fires increase the active layer depth for several years, which may alter the soil dynamics regulating soil GHG exchange. In a scenario of global warming, prolonged exposition of previously immobilized C could result in higher carbon dioxide emission during the early fire succession. However, without knowledge of the contribution of each respiration component combined with assessment of the warming and drying effects on both labile and recalcitrant soil organic matter throughout the soil profile, we cannot advance on the most relevant feedbacks involving fire and permafrost. Fires seem to have either negligible effects on methane (CH4) fluxes or a slight increase in CH4 uptake. However, permafrost thawing driven by climate or fire could turn upland boreal soils into temporary CH4 sources, depending on how fast the transition from moist to drier soils occurs. Most studies indicate a slight decrease or no significant change in postfire nitrous oxide (N2O) fluxes. However, simulations have shown that the temperature sensitivity of denitrification exceeds that of soil respiration; thus, the effects of warming on soil N2O emissions may be greater than on C emissions.

期刊论文 2020-05-01 DOI: 10.1016/j.envres.2020.109328 ISSN: 0013-9351
  • 首页
  • 1
  • 2
  • 末页
  • 跳转
当前展示1-10条  共11条,2页