Search Results (37)

Soil organic matter (SOM) dynamics in tropical montane ecosystems remain poorly understood, particularly regarding the relative importance of particulate versus mineral-associated fractions under varying disturbance regimes. This study investigated SOM fraction distribution across the Ericaceous and Afroalpine belts of Bale Mountains National Park, Ethiopia, an Andosol-dominated landscape subject to recurrent fire. Using a stratified sampling design (n = 30 plots) across four vegetation classes (Ericaceous belt, fragmented Ericaceous belt, herbaceous and heathland, and giant Lobelia areas), three fire history categories (<10, 10–25, and >25 years since fire), and three topographic positions (northern slopes, southern slopes, and central plateau), we quantified coarse particulate organic matter (cPOM: 149–2000 μm), fine particulate organic matter (fPOM: 53–149 μm), and mineral-associated organic matter (MAOM: <53 μm). Particulate fractions dominated the SOM pool, with cPOM and fPOM together accounting for >99% of measured organic carbon. Multivariate ordination revealed a primary gradient (PC1, 61.7%) contrasting particulate-dominated soils in less disturbed areas with relatively MAOM-enriched soils in fire-impacted and fragmented zones. A global comparison reveals a profound stability gap: the Bale Mountains utilize <2% of the mineral stabilization potential of comparable Andosols, demonstrating that extreme fire frequency (<25 yr return interval) overrides even the most reactive mineralogy. We critically evaluate whether standard size-based fractionation adequately captures mineral-associated carbon in volcanic soils and discuss methodological limitations. These results provide baseline data for conservation planning in this biodiversity hotspot and underscore the need for fire management strategies that balance ecological integrity with carbon storage objectives. Full article

The Gilé National Park (PNAG for its acronym in Portuguese), located in central Mozambique is one of the most important protected areas in the country. It is one of the last remnants of intact Miombo woodlands, providing critical habitat for endemic biodiversity. Fires are an important ecological factor in Miombo, but changes in fire regimes may compromise the stability of this ecosystem and thus, the conservation value of PNAG. This study assessed fire patterns and mapped fire risk in support of adaptive management in the PNAG. We investigated Miombo fire regime over 23 years (2001 to 2023) in terms of return interval, frequency, temporal distribution, spatial density and intensity, extent, and severity, by using two Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite products (MCD14ML active fire; MCD64A1 burned area). Primary risk drivers were established and spatial fire likelihood mapped, using the Random Forest algorithm. Analysis revealed pronounced late dry season burning (August–October) affecting approximately 60% of the PNAG annually, especially in central-northern and eastern landscapes. Remarkably, 88% of the park maintains a 1-to-2-year fire return interval across the entire fire season (May–October) while only 7% maintains return frequencies of 3-to-4-year cycles. The latter is important for maintaining Miombo ecosystem functionality. Medium to medium–high fire severity covered 98% of the total fire extension. Climate-related drivers and hunting activities were identified as key fire initiators, especially in central areas of the park. The findings demonstrate an urgent need for spatially differentiated fire management action through prescribed burning to maintain PNAG’s ecological resilience and conservation value. Full article

Due to climate effects and human influences, wildfire regimes in boreal forests are changing, leading to profound ecological consequences, including shortened fire return intervals and elevated tree mortality. However, a critical knowledge gap exists concerning the spatiotemporal dynamics of fire-induced tree mortality specifically within the vast North American boreal forest, as previous studies have predominantly focused on Mediterranean and tropical forests. Therefore, in this study, we used satellite observation data obtained by the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra MCD64A1 and related database data to study the spatial and temporal variability in burned area and forest mortality due to wildfires in North America (Alaska and Canada) over an 18-year period (2003 to 2020). By calculating the satellite reflectance data before and after the fire, fire-driven forest mortality is defined as the ratio of the area of forest loss in a given period relative to the total forest area in that period, i.e., the area of forest loss divided by the total forest area. Our findings have shown average values of burned area and forest mortality close to 8000 km²/yr and 40%, respectively. Burning and tree loss are mainly concentrated between May and September, with a corresponding temporal trend in the occurrence of forest fires and high mortality. In addition, large-scale forest fires were primarily concentrated in Central Canada, which, however, did not show the highest forest mortality (in contrast to the results recorded in Northern Canada). Critically, based on generalized linear models (GLMs), the results showed that fire size and duration, but not the burned area, had significant effects on post-fire forest mortality. Overall, this study shed light on the most sensitive forest areas and time periods to the detrimental effects of forest wildfire in boreal forests of North America, highlighting distinct spatial and temporal vulnerabilities within the boreal forest and demonstrating that fire regimes (size and duration) are primary drivers of ecological impact. These insights are crucial for refining models of boreal forest carbon dynamics, assessing ecosystem resilience under changing fire regimes, and informing targeted forest management and conservation strategies to mitigate wildfire impacts in this globally significant biome. Full article

Selection forestry sustains timber production and stand structural complexity via partial harvesting. However, regeneration initiated by harvesting may function as fuel ladders, providing pathways for fire to reach the forest canopy. We sought potential mitigation approaches by simulating stand growth and potential wildfire behavior over a century in stands dominated by coast redwood (Sequoia sempervirens (Lamb. ex. D. Don) Endl.) on California’s north coast. We used the fire and fuels extension to the forest vegetation simulator (FFE-FVS) to compare group selection (GS) to single-tree selection silviculture with either low-density (LD) or high-density (HD) retention on a 20-year harvest return interval. These three approaches were paired with six options involving vegetation management (i.e., hardwood control or pre-commercial thinning (PCT)) with and without fuels treatments (i.e., prescribed fire or pile burning), or no subsequent vegetation or fuel treatment applied after GS, HD, or LD silviculture. Fuel treatment involving prescribed fire reduced hazardous fuel loading but lowered stand density and hence productivity. Hardwood control followed by prescribed fire mitigated potential wildfire behavior and promoted dominance of merchantable conifers. PCT of small young trees regenerating after selection harvests, followed by piling and burning of these cut trees, sustained timber production while reducing potential wildfire behavior by approximately 40% relative to selection silviculture without vegetation/fuel management, which exhibited the worst potential wildfire behavior. Full article

Climate models have predicted changes in woody plant growth, vitality, and species distribution. Those changes are expected mainly within the boundaries of species ranges. We studied the influence of changing hydrothermal and burning-rate regimes on relict pine stands at the southern edge of the Pinus sylvestris range in Siberia. We hypothesize that (1) warming has stimulated pine growth under conditions of sufficient moisture supply, and (2) increased burning rate has threatened forest viability. We found that the increase in air temperature, combined with the decrease in soil and air drought, stimulated tree growth. Since the “warming restart” around 2000, the growth index (GI) of pines has exceeded its historical value by 1.4 times. The GI strongly correlates with the GPP and NPP of pine stands (r = 0.82). Despite the increased fire rate, the GPP/NPP and EVI index of both pine stands and surrounding bush–steppes are increasing, i.e., the pine habitat is “greening” since the warming restart. These results support the prediction (by climatic scenarios SSP4.5, SSP7.0, and SSP8.5) of improvement in tree habitat in the Siberian South. Meanwhile, warming has led to a reduction in the fire-return interval (up to 3–5 y). Although the post-fire density of seedlings on burns (ca. 10,000 per ha) is potentially sufficient for pine forest recovery, repeated surface fires have eliminated the majority of the undergrowth and afforestation. In a changing climate, the preservation of relict pine forests depends on a combination of moisture supply, burning rate, and fire suppression. Full article

We evaluated the effects of different fire regimes on the ground-ant community from a savanna (Cerrado) reserve in southern Brazil, where a process of woody encroachment has been taking place. Ants are a dominant faunal group in tropical savannas. Over ~8 years, experimental plots were protected from fire or burned every one or two years. An additional treatment (adaptive) included annual fires and a reduction in woody biomass to increase fuel loads. Ants were collected prior to the first prescribed fire and again four times. We expected that fire would increase the diversity and overall abundance of open-savanna ant specialists, depending on the extent of changes in vegetation structure. Changes in litter depth, grass cover and bare ground in burned plots were most evident 88 months after the first fire and did not differ between fire regimes. Similarly, overall ant species richness and occurrence neither differed between fire treatments nor from the control. However, burned plots showed a significant increase in the richness and occurrence of open savanna specialists, and a decrease in species most typical of dense savanna or dry forests. As ant responses did not differ between the annual, biennial, and adaptive treatments, we suggest that a fire return interval of two years is enough for reverting the loss of open savanna ant specialists in areas that have been protected from fire for decades. Full article

The mechanism through which fine root biomass affects soil carbon accumulation after prescribed burning remains unclear. In this study, the biomass of fine roots in different life forms (larch, shrub, and grass) and the total soil carbon (STC) were determined after prescribed burning. Relative to a control, the total soil carbon increased one week after the fire (11.70 mg·g⁻¹; 28.1%) and decreased after 8 months (7.33 mg·g⁻¹; 16.7%), returning to control levels 10 months post-fire. There was a reduction in the larch fine root biomass (FRB) (0.20–0.48 t·ha⁻¹; 35.3%–46.1%; these ranges represent the significant variation interval of fine root biomass after the fire across different time periods, compared to the control) but an increase in the shrub FRB (0.06–0.14 t·ha⁻¹; 101.6%–158.4%) and herb FRB (0.06–0.13 t·ha⁻¹; 591%–3200%) during the vegetation recovery process after the fire. The complementary growth of different plant life forms contributed to the changes in FRB. This also caused changes in the different life forms of FRBs’ effects on STC. Prescribed burning increased the contribution of FRB to STC. The compensatory growth of fine roots from different life forms drives the stabilization of the soil carbon pool after prescribed burning. Prescribed burning reduced the litter fuel and changed the FRB of different life forms, but it did not affect the long-term accumulation of STC. Full article

Objectives: Following the COVID-19 pandemic, global epidemiological trends demonstrate a return to pre-pandemic levels of respiratory syncytial virus (RSV) and influenza (Flu) A/B viruses. For the appropriate clinical management of viral infections, reliable and timely diagnosis is crucial. The clinical presentation of these respiratory viral infections shows significant overlaps; thus, the syndromic diagnosis of these infections becomes challenging. The goal of this study was to compare the performance of three multiplex real-time PCR-based platforms for the detection of SARS-CoV-2, Flu A, Flu B, and RSV. Materials and Methods: A retrospective study was performed on 200 de-identified nasopharyngeal and oropharyngeal specimens. All samples were tested simultaneously on three PCR-based platforms for the detection of SARS-CoV-2, Flu A, Flu B, and RSV: HealthTrackRx’s real-time PCR Open Array^® respiratory panel, TrueMark™ SARS-CoV-2, Flu A, Flu B, RSV Select Panel, and BioFire^® RP2.1 Panel. The positive and negative predictive value of each test was evaluated at a 95% confidence interval. Results: Among the 200 tested samples, the TrueMark™ and OpenArray^® laboratory-developed tests (LDTs) showed a 100% concordance for the detection of SARS-CoV-2, Flu A, Flu B, and RSV. Overall agreement of 100% was observed for nasopharyngeal samples between the laboratory-developed tests and FDA-approved BioFire^® RP2.1 Panel. Diagnostic results for these four respiratory viruses, in clinical samples, between the LDTs and the FDA-approved comparator demonstrated full concordance. Conclusions: Respiratory viral infections represent one of the major global healthcare burdens. Consequently, the accurate detection and surveillance of these viruses are critical, particularly when these viruses are known to co-circulate. The excellent performance and full concordance of the LDTs, with the BioFire^® Respiratory RP2.1 panel, in detecting SARS-CoV-2, Flu A, Flu B, and RSV shows that these tests can be confidently implemented for the clinical testing of respiratory viral infections. Full article

Wildfires are an intrinsic and vital driving factor in the Miombo ecosystem. Understanding fire regimes in Miombo is crucial for its ecological sustainability. Miombo is dominant in Central Mozambique, having one of the highest fire incidences in the country. This study evaluated the spatio-temporal patterns of fire regimes (intensity, seasonality, frequency and fire return interval) in the LevasFlor Forest Concession (LFC), Central Mozambique using remotely sensed data from 2001 to 2022. We conducted hotspot spatial statistics using the Getis-Ord Gi* method to assess fire distribution and patterns. The results revealed that 88% of the study area was burnt at least once from 2001 to 2022, with an average burned area of 9733 ha/year (21% of LFC’s total area). Fires were more likely to occur (74.4%) in open and deciduous Miombo types. A total of 84% of the studied area, burned in a range of 4 to 22 years of fire return interval (FRI) over the 21 assessed. Only 16% of the area was affected by high to very high FRI (1 to 4 years), with an average FRI of 4.43 years. Generally, fires are more frequent and intense in September and October. These results highlight the usefulness of remote sensing in evaluating long-term spatiotemporal fire trends for effective fire management strategies and control measures in African savanna ecosystems. Full article

Many plant species are well-adapted to historical fire regimes. An increase in the severity, frequency, and extent of wildfires could compromise the regenerative capacity of species, resulting in permanent shifts in plant diversity. We surveyed extant vegetation and soil seed banks across two forest types with contrasting historical fire regimes—Shrubby Dry Forest (fire return interval: 10–20 years) and Sub-Alpine Woodland (50–100 years). Over the past 20 years, both forests have been subject to repeated, high-severity wildfires at intervals significantly shorter than their historical return intervals. We examined the soil seed bank response to fire-cued germination, and whether the plant diversity in soil seed banks and extant vegetation demonstrated similar responses to short-interval, high-severity wildfires. The soil seed bank demonstrated a positive response to heat in combination with smoke, and for the Sub-Alpine Woodland, this was limited to sites more frequently burnt by fire. With an increase in fire frequency, there was a decline in species richness and Shannon’s Diversity and a shift in species composition in both extant vegetation and the soil seed bank. The fire frequency effects on the relative richness of trait associations were restricted to the Shrubby Dry Forest, and included an increase in short-lived obligate seeders, wind-dispersed species, and ant-dispersed shrubs in burnt relative to long unburnt sites in both extant vegetation and the soil seed bank. Graminoids were the most abundant component of the soil seed banks of Sub-Alpine Woodlands, and this increased with more frequent fire, with a similar trend (p = 0.06) in extant vegetation. Clear shifts in plant diversity in both soil seed banks and extant vegetation in forest types with contrasting historical fire regimes suggest that emerging fire regimes are pushing ecosystems beyond their historical range of variability, including potentially more flammable states and a decline in the buffering capacity of soil seed banks. Full article

Forest ecosystem attributes and their spatial variation across the landscape have the potential to subsequently influence variations in fire behavior. Understanding this variation is critical to fire managers in their ability to predict fire behavior and rate of spread. However, a fine-scale description of fuel patterns and their relationship with overstory and understory attributes for north-central Appalachia is lacking due to the complicated quantification of variations in topography, forest attributes, and their interactions. To better understand the fire environment in north-central Appalachia and provide a comprehensive evaluation based on fine-scale topography, ninety-four plots were established across different aspects and slope positions within an oak–hickory forest located in southeast Ohio, USA, which historically fell within fire regime group I with a fire return interval ranging from 7 to 26 years. The data collected from these plots were analyzed by four components of the fire environment, which include the overstory, understory, shrub and herbaceous layers, surface fuels, and fuel conditions. The results reveal that fuel bed composition changed across aspects and slope position, and it is a primary factor that influences the environment where fire occurs. Specifically, the oak fuel load was highest on south-facing slopes and in upper slope positions, while maple fuel loads were similar across all aspects and slope positions. Oak and maple basal areas were the most significant factors in predicting the oak and maple fuel load, respectively. In the shrub and undergrowth layers, woody plant coverage was higher in upper slope positions compared to lower slope positions. Overstory canopy closure displayed a significant negative correlation with understory trees/ha and woody plant variables. The findings in this study can provide a better understanding of fine-scale fuel bed and vegetation characteristics, which can subsequently feed into fire behavior modeling research in north-central Appalachia based on the different characterizations of the fire environment by landscape position. Full article

C4 grasses coevolved with fires, employing specialized adaptive traits to recover from recurrent fires of varying regimes, thereby maintaining plant diversity and plant population stability. However, the knowledge of how C4 bunchgrasses recover from varying fire return intervals (FRIs) is limited. Biomass, tillering, flowering, and growth-related traits of Digitaria eriantha, Themeda triandra, Sporobolus fimbriatus, and Cymbopogon plurinodis were assessed in 0- (unburned), 1-, 2-, and 4-year FRIs, each applied in two 0.5 ± 0.01 ha plots from 1980–2022 at the University of Fort Hare research farm, South Africa. FRIs and grass species interacted significantly on biomass production, crown size, tiller production, and reproductive tillers, with responses varying interspecifically depending on the FRI. Cymbopogon plurinodis attained higher total biomass in 1-year FRI, whereas T. triandra produced relatively low biomass in all FRIs compared to 0-year FRI. Nonetheless, T. triandra attained nearly two to three-fold more tillers per plant and three to five-fold more reproductive tillers in 2- and 4-year FRIs compared to other FRIs. Similarly, S. fimbriatus had two-fold more reproductive tillers in 2-year FRIs compared to 0- and 1-year FRIs. We deduce that C4 bunchgrasses respond differentially under recurrent fires depending on the fire return interval, with 2- and 4-year FRIs promoting vegetative and sexual regeneration by enhancing tillering and flowering. Full article

The influence of fire regimes on soil microbial diversity in montane grasslands is a relatively unexplored area of interest. Understanding the belowground diversity is a crucial stepping-stone toward unravelling community dynamics, nutrient sequestration, and overall ecosystem stability. In this study, metabarcoding was used to unravel the impact of fire disturbance regimes on bacterial and arbuscular mycorrhizal fungal community structures in South African montane grasslands that have been subjected to an intermediate (up to five years) term experimental fire-return interval gradient. Bacterial communities in this study exhibited a shift in composition in soils subjected to annual and biennial fires compared to the controls, with carbon and nitrogen identified as significant potential chemical drivers of bacterial communities. Shifts in relative abundances of dominant fungal operational taxonomic units were noted, with Glomeromycota as the dominant arbuscular mycorrhiza observed across the fire-return gradient. A reduction in mycorrhizal root colonisation was also observed in frequently burnt autumnal grassland plots in this study. Furthermore, evidence of significant mutualistic interactions between bacteria and fungi that may act as drivers of the observed community structure were detected. Through this pilot study, we can show that fire regime strongly impacts bacterial and fungal communities in southern African montane grasslands, and that changes to their usually resilient structure are mediated by seasonal burn patterns, chemical drivers, and mutualistic interactions between these two groups. Full article

Alto Minho (in northwestern Iberia) is one of the European regions most affected by fires. Many of these fires originate from rangeland management of Atlantic heathlands, and, while being illegal, often are not actively suppressed. In this study, pastoral fires (autumn-to-spring fires unrecorded by authorities), spring wildfires, and summer wildfires were independently mapped and dated from remote sensing. Alto Minho burned at a mean annual rate of 5.0% of the territory between 2001 and 2020. Pastoral burning totalled 40,788 hectares during the period, accounting for 20% of the total burnt area. Rangeland burning occurs mostly from December to April, the rainiest months that guarantee the conditions for pasture renewal and fire self-extinction. The mean fire return interval of pastoral burning is slightly higher than that of wildfires (13 years vs. 11 years), except in part of the inner mountains where it dominates fire activity. Pastoral fires are more frequent and largely prevail over wildfires in the parishes with higher livestock quantities. Conversely, the largest wildfires and higher summer burnt areas correspond with very low livestock and nearly non-existing pastoral fires. Traditional fire knowledge should not be overlooked by fire management, as it contributes to more sustainable fire regimes and ecosystems. Full article

The state of Michoacán in central Mexico supplies nearly 50% of the global avocado trade in a region known as the Michoacan Avocado Belt or Avocadoland. Fire has been a component associated with regional land-use change processes. We documented fire regime attributes for the period 2000–2017, discussed the use of fire related to the expansion of avocado orchards, and evaluated the role of atmospheric variables and human infrastructure. There was a mean of 276 fires covering 3287 ha of forest per year. Over 80% of the burned area was covered by pine and pine–oak forests, with a strong correlation of ignitions with the distance to urban settlements, roads, agricultural plots, and avocado orchards. There is a median fire return interval of 2–3 years, and the distance to avocado orchards and main roads was highly correlated with fire recurrence. Final users of the international marketing of this fruit may be unaware of the fire-related land-use changes, namely, the damage to biodiversity, forest health, and water bodies, as well as to producers’ well-being, behind the great demand for avocados. The present conditions of insecurity and social conflict must be addressed to guarantee, among other things, the conservation of these diverse forests. Full article