Sheila Fernández Riveiro

En las últimas décadas, la problemática relacionada con los incendios forestales se ha intensificado, especialmente en la cuenca Mediterránea, lo que genera una grave amenaza para los ecosistemas y las poblaciones humanas. Aunque han disminuido en número, los incendios son de mayor intensidad y severidad, superando la capacidad de extinción (incendios de sexta generación). Las causas de este aumento son diversas: factores socioeconómicos (despoblación, cambio de uso de suelo), gestión forestal deficiente, políticas inadecuadas y el cambio climático, agravados por la desinformación y sensacionalismo mediático. En este contexto socioambiental y de necesidad de información es necesario reforzar la capacidad de los nuevos especialistas en las actividades de prevención y restauración mediante diferentes estrategias. Por un lado, mediante mejoras en la gestión forestal, lo que conlleva la creación de masas forestales más resistentes a la propagación de los incendios forestales y con mayor capacidad de regeneración natural; por otro lado, actuando sobre las causas que originan la ignición, es decir, desarrollando concienciación social sobre las mismas. El proyecto Plantando Cara al Fuego (PCF) es una iniciativa que busca mejorar la concienciación ambiental y la participación ciudadana en la lucha frente a los incendios forestales, mediante su implicación en proyectos donde se aplican los conocimientos académicos a necesidades de la comunidad. Para ello, PCF desarrolla proyectos de innovación educativa basados en Aprendizaje-Servicio (ApS), metodología que integra la formación universitaria con la prevención y la restauración forestal. El objetivo de este trabajo es recopilar experiencias desarrolladas entre 2020 y 2025 en distintas comunidades autónomas españolas en las que el estudiantado universitario de titulaciones diversas ha desarrollado proyectos de ApS, contribuyendo a resolver problemáticas reales de sus comunidades ligadas a los incendios forestales mediante el diseño y desarrollo de actividades en colaboración con entidades públicas y privadas. Así pues, se analizan 35 proyectos, clasificados en 5 categorías (prevención, restauración, formación, multidisciplinar y divulgación), junto con indicadores de impacto educativo y social de la iniciativa: número de estudiantes implicados, empresas e instituciones colaboradoras, productos generados, TFGs o TFMs defendidos o alcance real de estos proyectos en términos poblacionales. Los resultados evidencian que el ApS fortalece la competencia profesional y el compromiso ambiental del alumnado, contribuyendo a la gestión sostenible del territorio.

Slash and burn treatments are often recommended and employed for controlling the invasive tree Acacia dealbata Link. In this study, we aimed to evaluate the effectiveness of this approach. We established eight experimental blocks with burn, slash and slash-and-burn treatments distributed across central Portugal. The density and height of new seedlings and resprouts of the invasive alien plant were monitored for three years. Our results showed that slash treatments stimulated resprouting, while burn treatments promoted seed germination. Resprouts and seedlings were significantly taller in the slash treatments compared to the burn treatments. When combined treatments were applied, different combinations of slash-and-burn reduced the number of resprouts and seedlings; however, the minimum stem density remained at 6.5 stems m⁻², compared to 0 in the control plots. These results demonstrate that, under the conditions of this study, slash-and-burn treatments without follow-up interventions are not effective for controlling A. dealbata populations, despite their role in reducing the soil seed bank.

Many invasive alien species (IAS) produce secondary metabolites that affect how other plants function (allelopathic compounds) and can drive other species invasion, as proposed by the invasional meltdown hypothesis. Acacia melanoxylon and Eucalyptus globulus are two of such species. In this study, we analyzed the germination response of seven IAS (Acacia dealbata, Acacia mearnsii, Acacia melanoxylon, Acacia longifolia, Eucalyptus globulus, Paraserianthes lophantha, Phytolacca americana) and a native biotest species (Lactuca sativa) to the application of two different aqueous extracts at two different concentrations of donor species A. melanoxylon and E. globulus. Extract compounds were identified by UHPLC-ESI-QTOF-MS. Eucalyptus aqueous extracts significantly reduced germination in three species (A. dealbata, E. globulus, P. americana). The germination of all the species tested was reduced with acacia aqueous extracts. Our results support the postulates of the Biochemical Recognition Hypothesis in that seeds gauge establishment potential based on phytochemical release of other plants. Furthermore, A. melanoxylon and E. globulus lowered their own germination, suggesting that these species exhibit intraspecific biochemical recognition. We also found support for the Novel Weapons Hypothesis in the case of L. sativa as a native species. Our research shows that phytochemicals are a component of plant-plant interactions, including the invasion process.

Fire is an ecological factor that affects ecosystem structure and functioning and determines later recovery of the ecosystem through the modification of biological processes, such as seed germination and seedling establishment. Another factor that modifies ecosystems is the presence of invasive alien species, which easily colonize new habitats after disturbances such as forest fires. Within this research, we analyzed the germination response to fire trough carbon and ash of three species that share habitat, one native species (Daucus carota L.) and two invasive alien species (Helichrysum foetidum (L.) Moench and Oenothera glazioviana Micheli) to identify and compare the effects of carbon and ash on the germination of these three species. For this purpose, germination tests were performed by using seeds treated with carbon and five concentrations of ash (from lower to higher -Ash1, Ash2, Ash3, Ash4, Ash5-), simulating remanent conditions after forest fires. Carbon and ash were obtained from the native species Ulex europaeus due to its abundancy in Atlantic shrubby ecosystems.In control conditions, germination of the three species studied was: D. carota (34.4%), H. foetdum (77.6%) and O. glazioviana (12.0%). The three species showed slightly different responses to fire factors. Carbon slightly reduced germination of native D. carota and stimulated germination of O. glazioviana, but statistically differences were not found with control. Germination response to ash depended on the species and the ash concentration applied. Lower concentrations of ash did not affect germination, intermediate concentrations reduced it, and higher concentrations inhibited germination at all. Regarding the species, both D. carota and O. glazioviana maintained its germination similar to control with Ash1 and Ash2, reduced it with Ash3, and inhibited it with Ash4 and Ash5. Germination of H. foetidum was the most affected. It only remained unaltered with Ash1 and was reduced progressively with Ash2 and Ash3. Treatments Ash4 and Ash5 totally inhibited it, as the other two species studied.At high concentrations, ash prevented the germination of the three species. In contrast, carbon did not modify it. After a forest fire, with soil covered by carbon and ash, germination of this species would be reduced or even removed if the concentration of ash is high. The difference success in this species after a forest fire could be explained by the amount of seeds produced or its response to other fire factors as heat or smoke.Funding. This work was supported by the Spanish Ministry of Science, Innovation and Universities, the Castilla y León Regional Government, the Galicia Regional Government and the European Regional Development Fund (ERDF) in the framework of the FIRESEVES (AGL2017-86075-C2-2-R) and WUIFIRECYL (LE005P20) projects and the Competitive Reference BIOAPLIC (ED431C2019/07) and the Strategic Researcher Cluster BioReDeS (ED431E 2018/09).

Forest fires are a global problem that affects almost all parts of the world. Southern Europe has been a fire prone area since prehistoric times. The northwest of the Iberian Peninsula, despite being an area abundant in rainfall, is currently a hotspot for forest fires. Forest fires produce carbon and ash as a result of the combustion of vegetation, these products can affect the germination behavior of plants.Due to climate change, forest fires are becoming more severe, more intense and more recurrent, and this context of disturbances facilitates and accelerates the replacement of native species by invasive alien species in many forest ecosystems. For this reason, we propose to compare the role of carbon and ash in the germination of two native species versus two invasive alien species. The two selected native species were Pinus pinaster Aiton and Salix atrocinerea Brot. and the two invasive species Paraserianthes lophanta (Willd.) I.C. Nielsen and Acacia melanoxylon R. Br. For it, 5 concentrations of ash and 1 concentration of carbon from 2 different origins (carbon from the same studied species and carbon from Ulex europaeus L.) were applied to seeds of these species. Mainly it stands out that the control germination of the native species was higher than that of the invasive species and the germination obtained under ash or carbon treatments was always similar or lower than the control germination. The germination obtained with the carbon of the own species was similar to the control germination and significantly higher than that achieved with the carbon of U. europaeus. Germination timing depends on each species studied, and invasive species take longer to complete their germination than native species (30-42 days versus 80-125 days). The carbon of the own species did not modify the germination timing while the carbon of Ulex did it in the two native species.Therefore, carbon and ash are two factors that modify the germination behavior of both the native species and the invasive species studied and can be used to manage plant regeneration after forest fire.Funding. This work was supported by the Spanish Ministry of Science, Innovation and Universities, the Castilla y León Regional Government, the Galicia Regional Government and the European Regional Development Fund (ERDF) in the framework of the FIRESEVES (AGL2017-86075-C2-2-R) and WUIFIRECYL (LE005P20) projects and the Competitive Reference BIOAPLIC (ED431C2019/07) and the Strategic Researcher Cluster BioReDeS (ED431E 2018/09).

Research Highlights: Data indicated that fire severity modulates natural regeneration of Cytisus scoparius and Salix atrocinerea communities and drives much stronger effects on the germination of the dominant species. Background and Objectives: Previous studies demonstrated that fire severity induces different behaviours in plant species. Mother plant age is an important feature that must also be considered in plans of forest restoration. The objectives were to determine, in field studies, the effect of fire severity on the natural regeneration of C. scoparius and S. atrocinerea communities, to know the role of mother plant age on the germination of seeds of C. scoparius and S. atrocinerea, and to quantify their germination response at different levels of fire severity, in laboratory settings. Material and Methods: We have analysed the role of fire severity on the natural regeneration of C. scoparius and S. atrocinerea communities considering cover and height. Forty 30 × 30 m plots were randomly located in C. scoparius and S. atrocinerea communities. Fire severity on the germination of dominant species was tested through different levels of smoke, charcoal, ash, and heat. Results: High severity reduced the vertical cover and growth in height of the two communities and favoured the increase of cover of woody species in the C. scoparius community and herbaceous species in the S. atrocinerea community. Mother plant age determined germination percentages of C. scoparius seeds. Germination of C. scoparius was increased by moderate heat, and heat and smoke; and fire severity greatly reduced germination of S. atrocinerea. Conclusions: The regeneration responses after fire were largely controlled by interactions between the fire severity and the individual species regeneration strategies. For restoration purposes, C. scoparius seeds should be treated with 80 °C and smoke for 10 min, in order to increase germination; however, Salix seeds should be used without treatment and immediately after dispersion.