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Impacts of fire on canopy structure and its resilience depend on successional stage in Amazonian secondary forests
No full textSecondary forests in the Amazon are important carbon sinks, biodiversity reservoirs, and connections between forest fragments. However, their regrowth is highly threatened by fire. Using airborne laser scanning (ALS), surveyed between 2016 and 2018, we analyzed canopy metrics in burned (fires occurred between 2001 and 2018) and unburned secondary forests across different successional stages and their ability to recover after fire. We assessed maximum and mean canopy height, openness at 5 and 10 m, canopy roughness, leaf area index (LAI) and leaf area height volume (LAHV) for 20 sites across South-East Amazonia (ranging from 375 to 1200 ha). Compared to unburned forests, burned forests had reductions in canopy height, LAI, and LAHV, and increases in openness and roughness. These effects were more pronounced in early successional (ES) than later successional (LS) stages, for example, mean canopy height decreased 33% in ES and 14% in LS and LAI decreased 36% in ES and 18% in LS. Forests in ES stages were less resistant to fire, but more resilient (capable of recovering from a disturbance) in their post-fire regrowth than LS stage forests. Data extrapolation from our models suggests that canopy structure partially recovers with time since fire for six out of seven canopy metrics; however, LAI and LAHV in LS forests may never fully recover. Our results indicate that successional stage-specific management and policies that mitigate against fire in early secondary forests should be implemented to increase the success of forest regeneration. Mitigation of fires is critical if secondary forests are to continue to provide their wide array of ecological services.Florestas secund & aacute;rias na Amaz & ocirc;nia s & atilde;o essenciais para captura de carbono, biodiversidade e conex & atilde;o entre fragmentos florestais. Por & eacute;m, seu crescimento & eacute; altamente amea & ccedil;ado pelo fogo. Usando varredura a laser aerotransportada (ALS), entre os anos de 2016 e 2018, analisamos m & eacute;tricas de dossel em florestas secund & aacute;rias queimadas (inc & ecirc;ndios ocorridos entre 2001 e 2018) e n & atilde;o queimadas em diferentes est & aacute;gios sucessionais e sua capacidade de recupera & ccedil;& atilde;o ap & oacute;s o fogo. Avaliamos a altura m & aacute;xima e m & eacute;dia do dossel, clareiras a 5 m e 10 m, rugosidade do dossel, & iacute;ndice de & aacute;rea foliar (LAI) e volume de altura da & aacute;rea foliar (LAHV) para 20 locais no sudeste da Amaz & ocirc;nia (variando de 375 ha a 1200 ha). Comparadas com florestas n & atilde;o queimadas, florestas queimadas tiveram redu & ccedil;& otilde;es na altura do dossel, LAI e LAHV, e aumentos nas clareiras e rugosidade. Esses efeitos foram mais pronunciados nos est & aacute;gios sucessionais iniciais (ES) do que em est & aacute;gios sucessionais mais tardios (LS), por exemplo, a altura m & eacute;dia do dossel diminuiu 33% no ES e 14% no LS e o LAI diminuiu 36% no ES e 18% no LS. Florestas no est & aacute;gio ES foram menos resistentes ao fogo, mas mais resilientes (capazes de se recuperar de uma perturba & ccedil;& atilde;o) em sua regenera & ccedil;& atilde;o p & oacute;s-fogo do que florestas no est & aacute;gio LS. A partir da extrapola & ccedil;& atilde;o de dados, nossos modelos sugerem que a estrutura do dossel se recupera parcialmente com o tempo desde o fogo para seis dos sete atributos do dossel, algumas m & eacute;tricas como LAI e LAHV em florestas LS talvez nunca se recuperem totalmente. Nossos resultados indicam que o manejo espec & iacute;fico do est & aacute;gio successional e pol & iacute;ticas que mitigam contra inc & ecirc;ndios em florestas secund & aacute;rias iniciais devem ser implementados para aumentar o sucesso da regenera & ccedil;& atilde;o florestal. A mitiga & ccedil;& atilde;o de inc & ecirc;ndios & eacute; cr & iacute;tica para que as florestas secund & aacute;rias continuem a fornecer sua ampla gama de servi & ccedil;os ecol & oacute;gicos
Using Biochar in Static and Dynamic Flow Systems to Remediate Per- and Polyfluoroalkyl Substances From Contaminated Stormwater Runoff
No full textBiochar has recently been identified as a potential solution for the remediation of organic micropollutants from contaminated water. Herein, we have assessed the potential mitigation of per- and polyfluoroalkyl substances (PFAS) by means of biochar adsorption as a green alternative to coal-based sorbents for PFAS-polluted stormwater systems. For this purpose, 13 biochar materials (originating from diverse feedstocks as well as intended for both commercial and research purposes) were initially screened for PFAS remediation capabilities in static flow systems. These experiments pointed to biochar sorption as a promising strategy for PFAS remediation, with some materials showing removal efficiencies of around 99% after 7 days of exposure. Though not all of the biochar materials tested performed equally, differences could be observed. As a next step, five biochar materials were studied under constant-flow column experiments for a duration of 69 days using real stormwater spiked with PFAS. Results showed that vast differences could be observed for the retention rates of the tested PFAS contaminants, with estimated bed volumes for an 80% breakthrough ranging from, for example, 13-60 for perfluorobutanesulfonic acid and from 4 to 53 for perfluoropentanoic acid. In terms of the PFAS backbone, both the static and dynamic flow experiments highlighted that long-chain PFAS showed stronger sorption onto the biochar surface than short-chain PFAS; however, no relevant impact could be identified in terms of the PFAS functional group. Overall, biochar is emerging as a promising and environmentally friendly approach for removing PFAS from contaminated stormwater
Evaluation of PBK models using the OECD assessment framework taking PFAS as case study
No full textPhysiologically based kinetic (PBK) models are becoming increasingly important in chemical risk assessment, helping in linking external and internal exposure concentrations, thereby supporting the development of regulatory health-based limits for chemicals with exposure from environmental, occupational, and consumer sources. To increase confidence in PBK models for regulatory purposes, the OECD published a guidance document in 2021 outlining the characterization, validation and reporting of PBK models. However, its use remains limited in chemical toxicology as reflected by the few publications that have applied it during model development. The aim of this study was to evaluate several published PBK models for Per- and polyfluoroalkyl substances (PFASs) as proof of concept to assess their validity and credibility for regulatory purposes, based on the OECD guidance. Out of 28 published PFASs human PBK models considered, 11 were selected for evaluation. The assessment used the OECD guidance document, encompassing two main areas: i) documentation (context/implementation, documentation, software implementation, verification, and peer engagement) and ii) assessment of model validity (biological basis, theoretical basis of model equations, input parameter's reliability, uncertainty and sensitivity analysis, goodness-of-fit and predictivity). To standardize this process, an online evaluation system based on the OECD guidance was developed and used for this model evaluation exercise. The collected data were analysed to assess the overall quality of published models and identify limitations in the current PFAS model landscape. Our analysis revealed opportunities for improvement in the biological representation within current PFAS models, particularly regarding the inclusion of diverse population groups. Currently, PFAS models primarily focus on only four compounds, highlighting an opportunity to extend coverage to other PFASs using read-across approaches for data-poor chemicals. Furthermore, our findings show that a harmonized approach for PBK model reporting is needed. To facilitate broader adoption of the OECD guidance, we developed and hosted an R Shiny template on our group's web server (https://app.shiny.insilicohub.org/Evaluation_PBPK/). This template can act as valuable tool for researchers evaluating PBK models according to the OECD guidance. GitHub: PBPK-OECD-EVALUATION
Disentangling dispersion from mean reveals true heterogeneity-diversity relationships
No full textUnderstanding the effect of heterogeneity is fundamental to numerous fields. In community ecology, classical theory postulates that habitat heterogeneity determines niche dimensionality and drives biodiversity. However, disparate heterogeneity-diversity relationships have been empirically observed, generating increasingly complex theoretical developments. Here we show that spurious heterogeneity-diversity relationships and subsequent theories arise as artifacts of heterogeneity measures that are mean-biased for bounded continuous variables. To solve this, we derive an alternative mean-independent measure of heterogeneity for beta and gamma distributed variables that disentangles statistical dispersion from mean. Using the mean-independent measure of heterogeneity, true monotonic positive heterogeneity-diversity relationships, consistent with classical theory, are revealed in data previously presented as evidence for both hump-shaped heterogeneity-diversity relationships and theories of an area-heterogeneity trade-off for biodiversity. This work sheds light on the source of conflicting results that have hindered understanding of heterogeneity relationships in broader ecology and numerous other fields. The mean-independent measure of heterogeneity is provided as a solution, essential for understanding true mean-independent heterogeneity relationships in wider research
Mitigation Measures in Hydropower-Regulated Lakes and Reservoirs
No full textWater levels in hydropower-managed lakes and reservoirs frequently fluctuate in response to demands for electricity. These sudden and occasionally extreme variations tend to severely degrade littoral zones, the shallow nearshore areas that provide vital habitats for many aquatic organisms. When these habitats are altered or disappear, many species struggle to survive, leading to a decline in biodiversity. As awareness of these ecological impacts increase, so too does interest in finding practical, targeted measures to improve conditions for the species that depend on these environments.Among the measures being explored is the use of Lake-in-Reservoirs (LiRs), which aim to buffer the effects of water level regulation on littoral habitats. LiRs are small and sheltered areas within reservoirs that are intended to uphold more stable hydrological conditions, even as the surrounding water body experiences fluctuations. By recreating the relatively stable conditions of natural littoral zones in lakes, LiRs may provide a refuge for species that are sensitive to hydrological disturbances.This essay examines the feasibility and potential of using LiRs to enhance biodiversity in regulated aquatic systems. A systematic literature review was conducted to identify documented LiR implementations, resulting in seven confirmed cases, all located in Sweden and Norway. This essay draws from these cases, as well as a broader range of scientific studies, industry reports, and technical documentation. It focuses on how LiRs function under different environmental and regulatory conditions, as well as the factors that affect their effectiveness.The findings suggest that LiRs can help preserve key ecological functions and partially offset the biodiversity loss. However, losses associated with hydropower operations and site-specific conditions, such as reservoir morphology, substrate composition, and local climate, appear to affect both the practical implementation of LiRs and the ecological outcomes they can achieve.In sum, LiRs appear to be a promising yet insufficiently explored method for supporting local biodiversity and lake productivity in regulated lakes and reservoirs. While they may not be suitable for every given setting, strategic planning and adaptation to specific local conditions can increase their effectiveness as a conservation measure. Nevertheless, more research is needed to identify where LiRs are most effective and how they can best support long-term ecosystem health and resilience
Effects of walnut shell biochar feed additive on rumen fermentation, nutrient utilization, and performance in fattening lambs
No full textConverting agricultural waste into biochar offers a promising approach to improve animal nutrition and mitigate environmental impacts. This study investigated the effects of dietary supplementation with walnut shell-derived biochar on growth performance, nutrient digestibility, and rumen fermentation characteristics in fattening male lambs. Twelve lambs (initial body weight: 34.4 kg) were randomly assigned to two dietary treatments: a control diet and a diet supplemented with 1 % walnut shell biochar, over a period of 60 days. The inclusion of 1 % walnut shell biochar did not significantly affect dry matter intake (DMI) (p = 0.08), average daily gain (ADG) (p = 0.06), or feed conversion ratio (FCR) (p = 0.47). However, lambs fed the walnut shell biochar diet had a higher final body weight compared to the control group (p = 0.05). In contrast, lambs fed the walnut shell biochar -supplemented diet showed significantly higher digestibility coefficients of organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (p < 0.05). Rumen fermentation parameters were also influenced by the walnut shell biochar supplement, with increased total volatile fatty acid (VFA) concentration (p = 0.03), higher propionate levels (p = 0.054), and reduced protozoa counts (p = 0.0003), while rumen pH (p = 0.76) and ammonia nitrogen (NNH3) concentrations (p = 0.64) remained unaffected. These findings suggest that walnut shell biochar may improve fiber and organic matter digestibility and beneficially modulate rumen fermentation without compromising growth performance in lambs
Black soldier fly larvae composting of plant-based food and agro- industry waste
No full textBlack soldier fly larvae (BSFL) composting is becoming increasingly recognised as a sustainable bioconversion technology aligned with circular economy principles. However, when applied to plant-based food and agro- industry waste—such as cucumber plant residuals, orange peels, and vegetable mixes—its biological efficiency and economic viability remains unclear. This study evaluated the effects of various pre-treatments (ammonia, fungal, enzymatic) and co-substrate additions (e.g., frass) on BSFL process efficiency, greenhouse gas and ammonia emissions, and larval biomass yield across both small- and large-scale systems. Whilst fungal and enzymatic pre-treatments improved material reduction, their impact on biomass conversion efficiency (BCE) was substrate- and scale-dependent. The addition of both enzymes and frass significantly enhanced BCE and larval yield in small-scale systems but was less effective at larger scales. Direct emissions of CH4 and N2O were low relative to CO2, however, ammonia pre-treatment increased NH3 emissions. Despite reduced larval yields, BSFL composting achieved substantial waste volume reduction and partial degradation of pesticide residues. These environmental benefits suggest that the technology may still offer a viable treatment pathway for nutritionally imbalanced, fibrous waste streams, particularly where conventional composting or anaerobic digestion is unsuitable. For successful large-scale implementation, system modifications—such as improved environmental control, passive harvesting strategies, and decentralised processing models—will be essential. Overall, BSFL composting presents a promising waste management solution for plant-based residues, with potential value lying more in environmental services than in larval biomass production
Reducing annotation dependency in automated rumen-fill scoring through pairwise comparisons and curvature analysis
No full textCreatine kinase B regulates glycolysis and de novo lipogenesis pathways to control lipid accumulation during adipogenesis
No full textWhite adipocyte differentiation or adipogenesis requires coordination of metabolic sensing and transcriptional modifications to orchestrate lipid storage. Creatine and its kinases are implicated in adipose energy buffering, but the roles of cytosolic (CKB) and mitochondrial (CKMT2) creatine kinases in adipogenesis are unclear. We find that both CKB and CKMT2 are progressively upregulated during differentiation. Functional studies show that CKB restrains de novo lipogenesis (DNL) by limiting activation of carbohydrate-responsive element-binding protein (ChREBP), a key regulator of lipogenic genes. Mechanistically, CKB interacts with AKT and regulates its activation in response to insulin. Loss of CKB causes persistent AKT-mTORC1 signaling, increases glycolytic flux, and enhances ChREBP activation, thereby promoting glucose-derived lipid synthesis. Thus, CKB acts as a metabolic rheostat linking creatine-kinase activity to insulin signaling and nutrient-responsive transcription. We propose a CKB-AKT-ChREBP regulatory axis that contributes to metabolic remodeling and lipid homeostasis during adipocyte differentiation
Can information framing increase farmers' uptake of Eco-schemes? a randomised controlled trial
No full textThe overall success of voluntary agri-environmental programmes often hinges importantly on the level of farmer participation. Their enrolment decisions are shaped by a complex set of behavioural factors, which can be targeted by designing specific behavioural interventions-such as nudges-that aim to improve farmers' uptake of these schemes. However, the effectiveness of these approaches in real-world settings remains understudied. Here, we use two subsequent randomized controlled trials to evaluate the effect of information treatments on farmers' enrolment rates and enrolled area in a new Eco-scheme for establishing Skylark plots, which has been implemented as part of the EU's Common Agricultural Policy in Slovenia. The first trial framed enrolment as an environmental gain or loss, while the second trial framed enrolment as a negative or positive descriptive norm. In both trials, interventions had no direct effect on enrolment rates nor on the area enrolled. However, for large farms and for farms with prior enrolment in agri-environmental measures, interventions influenced the enrolment decision and the area enrolled. Our results imply that the provision of untargeted information framing alone may be insufficient to boost enrolment of all farmers in agri-environmental measures. However, such interventions may affect the behaviour of some groups of farmers. To improve enrolment, we recommend better targeting of behavioural interventions, coupled with system-level changes