Advances towards an Integrated Assessment of Fire Effects on Soils, Vegetation and Geomorphological Processes

Fire Effects on Soils, Vegetation and Geomorphological Processe

Soil erosion after fire in volcanic terrain: assessment and implications for post-fire soil losses

Wildfires can dramatically modify the hydrologic and erosion response of ecosystems, increasing risks to population and assets downslope of fire affected hillslopes. This applies especially to volcanic areas in fire-prone regions which often exhibit steep terrain and high population densities. However, the effects of fire on key hydrologic and erosion parameters, which are critical for modelling runoff-erosion processes, predicting related post-fire risks and for selecting effective mitigation measures, have not been extensively assessed in this terrain type. Here we evaluate water erosion processes of two contrasting volcanic soils in recently burned forest areas of Tenerife (Canary Islands, Spain) at hillslope scale using erosion plots monitoring and rill erosion simulation experiments. The results show that both the lithology and the degree of weathering of the volcanic material govern the post-fire water erosion by concentrated flow (rill erosion experiments) and by the combination of interrill and rill erosion (erosion plots). Mature volcanic soils showed less susceptibility to erosion than weakly weathered volcanic soils and soils with non-volcanic lithologies. The results also show that the availability of easily detachable and transportable soil particles swiftly decreases after the fire, leading to the exhaustion of sediments and a decrease of the erosion rates with cumulative runoff events. These findings have direct implications for the modelling of runoff-erosion processes in volcanic terrain

Using Thermogravimetry as a Simple Tool for Nutrient Assessment in Fire Affected Soils

Thermogravimetry for Nutrient Assessment in Burned Soil

Effectiveness of Polyacrylamide, Wood Shred Mulch, and Pine Needle Mulch as Post-Fire Hillslope Stabilization Treatments in Two Contrasting Volcanic Soils

Post-fire hillslope stabilization treatments aim to counteract the impact of fire on key soil and hillslope properties and reduce runoff-erosion risks following forest fires. We evaluated the effectiveness of wood shred mulch, long-leaved pine needle mulch, and polyacrylamide (PAM) in reducing runoff and erosion in two fire-affected volcanic soils of contrasting wettability using rainfall simulations (55 mm h−1 for 30 min) at the microplot (0.25 m2) scale. Wood shreds and pine needles led to a reduction of runoff and erosion in both the wettable—(62% and 92%, respectively, for wood shreds, and 55% and 87%, respectively, for needle mulch) and the extremely water-repellent soils (44% and 61%, respectively, for wood shreds). PAM did not reduce runoff or erosion when applied to the extremely water-repellent soils, suggesting that PAM should not be applied in this terrain type. The results are encouraging in terms of these materials’ ability to provide effective and relatively economic mitigation treatments for fire-induced runoff-erosion risks in volcanic soils but more research is needed to determine whether the high effectiveness of pine needle mulch and wood shred mulch fully translates to coarser scales

Designing tools to predict and mitigate impacts on water quality following the Australian 2019/2020 wildfires: Insights from Sydney's largest water supply catchment

The 2019/2020 Australian bushfires (or wildfires) burned the largest forested area in Australia's recorded history, with major socio-economic and environmental consequences. Among the largest fires was the 280 000 ha Green Wattle Creek Fire, which burned large forested areas of the Warragamba catchment. This protected catchment provides critical ecosystem services for Lake Burragorang, one of Australia's largest urban supply reservoirs delivering ~85% of the water used in Greater Sydney. Water New South Wales (WaterNSW) is the utility responsible for managing water quality in Lake Burragorang. Its postfire risk assessment, done in collaboration with researchers in Australia, the UK, and United States, involved (i) identifying pyrogenic contaminants in ash and soil; (ii) quantifying ash loads and contaminant concentrations across the burned area; and (iii) estimating the probability and quantity of soil, ash, and associated contaminant entrainment for different rainfall scenarios. The work included refining the capabilities of the new WEPPcloud-WATAR-AU model (Water Erosion Prediction Project cloud-Wildfire Ash Transport And Risk-Australia) for predicting sediment, ash, and contaminant transport, aided by outcomes from previous collaborative postfire research in the catchment. Approximately two weeks after the Green Wattle Creek Fire was contained, an extreme rainfall event (~276 mm in 72 h) caused extensive ash and sediment delivery into the reservoir. The risk assessment informed on-ground monitoring and operational mitigation measures (deployment of debris-catching booms and adjustment of the water supply system configuration), ensuring the continuity of safe water supply to Sydney. WEPPcloud-WATAR-AU outputs can prioritize recovery interventions for managing water quality risks by quantifying contaminants on the hillslopes, anticipating water contamination risk, and identifying areas with high susceptibility to ash and sediment transport. This collaborative interaction among scientists and water managers, aimed also at refining model capabilities and outputs to meet managers' needs, exemplifies the successful outcomes that can be achieved at the interface of industry and science. Integr Environ Assess Manag 2021;17:1151–1161. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).During manuscript preparation J. Neris, C. Santin, R. Lew, and S.H. Doerr were supported by a Natural Environment Research Council grant (NE/R011125/1)

Innovación en las enseñanzas universitarias: experiencias presentadas en las III Jornadas de Innovación Educativa de la ULL

En este libro se recoge un conjunto de experiencias de innovación educativa desarrolladas en la ULL en el curso 2011-12. Se abordan distintos ámbitos y ramas del conocimiento, y ocupan temáticas variadas que han sido desarrolladas con rigor, y con un claro potencial para su extrapolación a efectos de la mejora educativa en el ámbito universitario. Esta publicación constituye una primera edición de una serie que irá recogiendo las experiencias de innovación educativa de la ULL. Este es un paso relevante para su impulso en nuestra institución, como lo es el de su vinculación con la investigación educativa, para potenciar su publicación en las revistas científicas en este ámbito cada vez más pujante y relevante para las universidades. Sobre todo representan el deseo y el compromiso del profesorado de la ULL para la mejora del proceso educativo mediante la investigación, la evaluación y la reflexión compartida de nuestras prácticas y planteamientos docentes

After the fire: biogeochemical effects of charcoal and ash on fire-affected landscapes

Vegetation fires are a global phenomenon that affect 3-5 million km2 every year. Both natural and caused by humans, fire burns through a very broad range of ecosystems, from boreal forest to tropical savannahs, exerting also a very broad range of effects. Despite this huge variability, there are two components always present after a fire: charcoal and ash. Charcoal, also known as pyrogenic carbon, is a key player in the carbon cycle from fires, due to its ability to act as a carbon sink. In addition, it can play a major role in the functioning of soils via its interactions with other elements and priming of native soil organic matter. Meanwhile, ash, the powdery fire residue, can be an important source of nutrients for the post-fire regrowing vegetation, but it can also be a source of water contamination when transported by wind and water to the hydrological networks after fire. This presentation will give an overview on the current knowledge of these two interlinked components of the wildfire-affected landscapes, highlighting current gaps and future research directions