Wildfires are considered a major disturbance to forest ecosystems in the Mediterranean countries of Southern Europe. Although ground-dwelling macroinvertebrates are crucial to many soil functions, there is a fundamental lack of understanding of how wildfires impact this community in the immediate term and of the role of stones in their survival. Hence, in the present study we assessed the immediate effects of wildfires in the ground-dwelling macroinvertebrate community found under stones by comparing communities in burnt and non-burnt Mediterranean oak forests.
View Article and Find Full Text PDFWildfires usually increase the hydrological and erosive response of forest areas, carrying high environmental, human, cultural, and financial on- and off-site effects. Post-fire soil erosion control measures have been proven effective at mitigating such responses, especially at the slope scale, but there is a knowledge gap as to how cost-effective these treatments are. In this work, we review the effectiveness of post-fire soil erosion mitigation treatments at reducing erosion rates over the first post-fire year and provide their application costs.
View Article and Find Full Text PDFBiochar application to soil has the potential to affect soil and vegetation properties that are key for the processes of runoff and soil erosion. However, both field and pot experiments show a vast range of effects, from strong reductions to strong increases in runoff and/or soil erosion. Therefore, this study aimed to quantify and interpret the impacts of biochar on runoff and soil erosion through the first systematic meta-analysis on this topic.
View Article and Find Full Text PDFThe magnitude of forest fires' impacts on the environment is directly related to the changes induced on soil physical, chemical and biological properties. Using available organic resources to rehabilitate burnt forest soils can help reduce post-fire soil fertility loss, accelerating ecosystem recovery. In the present study, the potential of four soil amendments: a mycotechnosol, a eucalypt residue mulch, dredged sediments from a freshwater lagoon and an organic-mineral biofertilizer, to improve the quality of burnt forest soils in terms of organic matter, carbon, nitrogen and phosphorus contents, was evaluated.
View Article and Find Full Text PDFWildfires are an environmental concern due to the loss of forest area and biodiversity, but also because their role as drivers of freshwater systems contamination by metals. In this context, the fish Gambusia holbrooki was used as a model, deployed for in situ exposure in watercourses standing within a recently burnt area and further assessment of toxic effects. The fish were exposed during 4 days at four different sites: one upstream and another downstream the burnt area and two within the burnt area.
View Article and Find Full Text PDFWildfires are a complex environmental problem worldwide. The ashes produced during the fire bear metals and PAHs with high toxicity and environmental persistence. These are mobilized into downhill waterbodies, where they can impair water quality and human health.
View Article and Find Full Text PDFWildfires are an important environmental problem in forested watersheds and can significantly alter water quality. Besides the reported ecotoxicological effects on pelagic species, the accumulation of post-fire contaminants in river sediments can also impair the benthic species. In this study, three sediment-dwelling species, Chironomus riparius, Atyaephyra desmarestii and Echinogammarus meridionalis, with different sensitivities, habitats, behaviours and/or feeding strategies, were exposed to water and sediments, in in-situ and in laboratory.
View Article and Find Full Text PDFForests in Mediterranean Europe including Portugal are highly susceptible to wildfires. Freshwaters are often exposed to post-wildfire contamination that contains several toxic substances, which may impose risk to freshwater organisms and ecosystem functions. However, knowledge on the impacts of post-wildfire runoffs from different origins on freshwater biota is scarce.
View Article and Find Full Text PDFAmong the various environmental disturbances caused by wildfires, their impacts within burnt areas and on the downhill aquatic ecosystems has been receiving increased attention. Post-fire rainfalls and subsequent runoffs play an important role in transporting ash and soil to aquatic systems within the burnt areas. These runoffs can be a diffuse source of toxic substances such as metals.
View Article and Find Full Text PDFFuture climate for the Mediterranean climatic region is expected to bring an increase in temperatures, decrease in the precipitation quantity and shifts in the seasonal precipitation pattern. Although the impacts of climate change on water resources have been relatively well explored for the Mediterranean climatic region, the specific consequences for reservoirs and, in particular, water availability and irrigation issues have been less studied. The objective of this work is two-fold: (i) to assess the impacts of future climate changes on water resources availability, quality (focusing on phosphorus loads as this is the limiting nutrient for eutrophication) and irrigation needs for two multipurpose reservoirs in southern Portugal; (ii) to suggest climate change adaptation strategies, especially for the agricultural sector.
View Article and Find Full Text PDFMediterranean forests are highly susceptible to wildfires, which can cause several impacts not only within burnt areas but also on downstream aquatic ecosystems. The ashes' washout from burnt areas by surface runoff can be a diffuse source of toxic substances, such as metals, when reaching the nearby aquatic systems, and can be noxious to aquatic organisms. The present work aimed at assessing the ecotoxicological effects of post-fire contamination on two aquatic producers (the microalgae Raphidocelis subcapitata and the macrophyte Lemna minor) through in-situ bioassays, validating the obtained results with the outcomes of laboratory bioassays with surface water collected simultaneously.
View Article and Find Full Text PDFCarbon dioxide (CO) efflux from soil represents one of the biggest ecosystem carbon (C) fluxes and high-magnitude pulses caused by rainfall make a substantial contribution to the overall C emissions. It is widely accepted that the drier the soil, the larger the CO pulses will be, but this notion has never been tested for water-repellent soils. Soil water repellency (SWR) is a common feature of many soils and is especially prominent after dry periods or fires.
View Article and Find Full Text PDFIn the last decades, land-use changes have made Mediterranean forests highly susceptible to wildfires, which can cause several impacts not only on burnt areas, but also on adjacent aquatic ecosystems. Post-fire runoff from burnt areas may transport toxic substances to streams by surface runoff, including polycyclic aromatic hydrocarbons (PAHs) and metals, which can be noxious to aquatic organisms. Impacts on aquatic ecosystems can be related to fire severity, forest type and the exposure period; however, these factors have not been investigated in tandem.
View Article and Find Full Text PDFThis work relied on the use microcosms to evaluate the individual and the combined effects of different levels of copper sulfate (0.0, 0.013, 0.
View Article and Find Full Text PDFThe impacts of climate and associated socio-economic changes on water availability, including supply and demand, quality, and storage volume, were evaluated for the Vale do Gaio reservoir in southern Portugal, located in a dry Mediterranean climate and already under drought stress. The SWAT model was applied with 6 scenarios for 2071-2100, involving two storylines (A1B and B1) with individual changes in climate (-9% rainfall, increasing in winter by +28 to +30%), socio-economic conditions (an increase in irrigation demand by 11%, and a replacement of cereals and pastures by sunflower), and a combination of both. Most future scenarios resulted in lower water availability, due to lower supply (-19 to -27%) combined with higher irrigation demand (+3 to +21%).
View Article and Find Full Text PDFThe number of wildfires has markedly increased in Mediterranean Europe, including in Portugal. Wildfires are environmentally concerning, not only due to the loss of biodiversity and forest area, but also as a consequence of environmental contamination by specific compounds including metals and polycyclic aromatic compounds (PAHs). These contaminants, mostly bound to ashes, can reach downstream water bodies, namely through surface runoff, being ultimately dispersed by vast areas and contacting with aquatic biota.
View Article and Find Full Text PDFMulching is an effective post-fire soil erosion mitigation treatment. Experiments with forest residue mulch have demonstrated that it increased ground cover to 70% and reduced runoff and soil loss at small spatial scales and for short post-fire periods. However, no studies have systematically assessed the joint effects of scale, time since burning, and mulching on runoff, soil loss, and organic matter loss.
View Article and Find Full Text PDFWildfires can play an important role in the environmental distribution of major and trace elements, including through their mobilization by fire-induced runoff and associated transport of soil and ash particles. In particular, fire-induced inputs of these elements into the environment are relevant due to their toxicity and environmental persistence. This study aimed to evaluate the role of wildfire and time-since-fire on the redistribution of major and trace elements, which is a topic poorly documented.
View Article and Find Full Text PDFIn order to maintain and improve the water quality in European rivers, the Water Framework Directive (WFD) requires an integrated approach for assessing water quality in a river basin. Although the WFD aims at a holistic understanding of ecosystem functioning, it does not explicitly establish cause-effect relationships between stressors and changes in aquatic communities. To overcome this limitation, the present study combines the typical WFD physicochemical and biological approaches with an ecotoxicological approach.
View Article and Find Full Text PDFFor several years now, forest fires have been known to increase overland flow and soil erosion. However, mitigation of these effects has been little studied, especially outside the USA. This study aimed to quantify the effectiveness of two so-called emergency treatments to reduce post-fire runoff and soil losses at the microplot scale in a eucalyptus plantation in north-central Portugal.
View Article and Find Full Text PDFThe Cértima River is the principal source of water flowing into the Pateira de Fermentelos, which is one of the largest natural lakes of the Iberian Peninsula and has elevated conservation value. This study aims at a more comprehensive understanding of the spatial pattern in water quality and, thus, pollution problems in and especially upstream of the Pateira, including a comparison with a prior study in 2003. To this end, surface water samples were collected, in May 2007, at 29 sites covering the basin's four main types of water bodies, and analysed for electrical conductivity, dissolved oxygen, biochemical oxygen demand, total suspended solids, various nitrogen species, orthophosphate and chlorophyll a.
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