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1.
J Environ Manage ; 316: 115212, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35550959

RESUMEN

Forest fires intensify sediment transport and aggravate local and off-site consequences of soil erosion. This study evaluates the influence of post-fire measures on structural and functional sediment connectivity (SC) in five fire-affected Mediterranean catchments, which include 929 sub-catchments, by using the "aggregated index of connectivity" (AIC) at two temporal scenarios: I) immediately after the fire and before implementing post-fire practices ('Pre-man'), and II) two years after the fire ('Post-man'). The latter includes all the emergency stabilization practices, that are hillslope barriers, check-dams and afforestation. The stream system was set as the target of the computation (STR), to be representative of intense rainfall-runoff events with effective sediment delivery outside the catchments. Output normalization (AICN) allows comparing the results of the five basins between them. The sedimentological analysis is based on specific sediment yield (SSY) -measured at the check-dams installed after the fire -, and this data is used for output evaluation. Stream density and slope variables were the most influential factors on AICN-STR results at the sub-catchment scale. Post-fire hillslope treatments (barriers when built in high densities and afforestation) significantly reduced AICN-STR in comparison with untreated areas in both structural and functional approaches. Despite the presence of hillslope treatments, the higher erosive rainfall conditions resulted in higher AICN-STR values in the Post-man scenario (functional approach). A positive and good correlation was found between the measured SSY and the AICN-STR changes due to the post-fire practices and vegetation recovery, showing the good correspondence of the computation results and the real sediment dynamics of the studied catchments. Overall, AICN demonstrated to be a useful and versatile tool for post-fire management, which needs further research to optimize its applicability.


Asunto(s)
Incendios , Ríos , Ecosistema , Bosques , Humanos , Suelo
2.
J Environ Manage ; 277: 111405, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33032003

RESUMEN

Knowledge of forest soil ecology is necessary to assess vulnerability to disturbances, such as wildfires, and improve its microbial diversity and functional value. Soil microbiota play an important role in forest soil processes and are a key driver of postfire recovery, but they are very vulnerable to heat. According to future scenarios for climate and land-use change, fire regimes will undergo transformations in semiarid terrestrial ecosystems, mainly in the Mediterranean Basin. To develop tools for forest management in fire-prone areas, i.e., fire prevention, we assessed the impact of prescribed burnings on soil microorganisms in Mediterranean mixed pine forests. We hypothesised that low severity fire burns would not influence the functional diversity of soil microorganisms, although the burning season could influence that response due to seasonal variations in its vulnerability. We used the Biolog EcoPlate System to record soil biological indicators and assess the effect of the prescribed burning season (early or late season) on bacterial communities, including the soil-plant interphase. The soil microbiome response differed significantly according to vegetation coverage but prescribed burning season was not directly related. Burning increased the proportions of soil organic matter and soil organic carbon, and also promoted cation-exchange capacity and total phosphorus, which were higher following spring burns. Microbial richness and the Shannon-Weaver diversity index both showed a positive correlation with vegetation cover. However, microbial richness was triggered after burning uncovered patches of vegetation. We also noted differences in the usage pattern for the six substrate groups defined in our study: the use of carboxylic acids, amino acids and carbohydrates was higher in unburned plots and those subject to late burns, whereas amino acids did not predominate in early burn plots.


Asunto(s)
Incendios , Pinus , Carbono , Ecosistema , Bosques , Estaciones del Año , Suelo
3.
J Environ Manage ; 235: 250-256, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30684810

RESUMEN

In the Mediterranean Basin, changes in climate and fire regime (increased recurrence and severity) reduce ecosystem services after wildfires by increasing soil degradation and losses in plant diversity. Our study was a biological approach to relate soil properties to vegetation recovery and burn severity. We focused our study on the natural recovery of the soil-plant interphase in Pinus halepensis Mill. forests located in the SE of Iberian Peninsula, a semiarid climate. We included some chemical properties 3 years after fire (available phosphorus (P) and soil organic carbon (Corg), among others), and biological soil indicators 3 and 5 years after fire (i.e. basal soil respiration (BSR), microbial biomass carbon (Cmic), carbon mineralization coefficient (Cmineral), metabolic quotient (qCO2) and microbial quotient (Cmic:Corg)). We analyzed the activity of three different enzymes: urease (UR), phosphatase (PHP) and ß-glucosidase (GLU). The changes in most chemical properties were ephemeral, but P and Corg showed higher values in burned areas, and the highest were found for low-moderate severity. Plant recovery was the triggering factor for the recovery of Corg and biological soil function. Burn severity and time after fire influenced Cmic and the Cmic:Corg, which were higher for moderate-high severity 3 years later, but were below the unburned values 5 years after fire. The microbial activities of GLU and UR were recovered in burned areas 5 years after fire. The PHP values lowered according to higher burn severity and time after fire. The soil ecological trends obtained by a principal component analysis revealed a relationship linking GLU, BSR and qCO2 that explained soil response to burn severity. PHP, Cmic and Cmic:Corg explained most of the variability related to time after fire. Our results provide insights into how burn severity, in Mediterranean fire-prone Aleppo pine stands, modulated the natural plant recovery linked to soil biochemical and microbiological response to fire. High burn severity limited natural vegetation recovery, and both reduced biological soil functionality. This knowledge can be implemented in post-fire planning to apply post-fire management (for mitigation and restoration) in which the "no intervention" tool should be contemplated. These findings provide information to be applied in adaptive forest management to improve the resilience of vulnerable ecosystems and to reduce burn severity in future fire events.


Asunto(s)
Incendios , Pinus , Incendios Forestales , Ecosistema , Bosques , Suelo
4.
J Environ Manage ; 232: 1021-1027, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33395754

RESUMEN

Prescribed fire removes or reduces the plant material that is prone to forest fires by creating fuel discontinuity and minimising fire intensity. This forest management tool potentially impacts Mediterranean ecosystems hydrological response by influencing water infiltration into soil. As direct measurements (e.g. by infiltrometers) of unsaturated infiltration in soil subjected to prescribed fires are scarce, this study has evaluated changes in soil hydraulic conductivity (SHC) using Minidisk infiltrometer after prescribed fires in representative plots of forests in the Iberian Peninsula under Mediterranean semi-arid conditions: (i) pure forest of Black pine Arnold ssp salzmannii; (ii) mixed forest of Maritime and Black pine; (iii) mixed forest of Aleppo and Maritime pine. The results have shown that fire reduced the organic layer thickness and its organic matter content. Consequently, after the prescribed fire the water content of burned plots was always lower than in untreated soils; conversely, the reverse soil behaviour was noticed before applying fire. Compared to the untreated soils, and with very few exceptions, prescribed fire did not cause significant changes in SHC. No general patterns in the comparisons between treatments (burned/unburned soils), in time evolution after fires and in the interactions between these effects were detected. This means that the SHC of burned soils followed the temporal variations of untreated soils. The lack of significance of these differences between treatments could be due to the low-fire severity and the limited effect of temperature in the mineral layer on soil hydraulic properties. This effect was expected and agrees with other studies. Overall prescribed fires did not alter SHC in Mediterranean forest ecosystems under unsaturated conditions since fire was of low-severity.

5.
J Environ Manage ; 246: 229-238, 2019 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-31176984

RESUMEN

Postfire restoration practices encompass those which aim to reduce negative wildfire impacts and to improve burned area rehabilitation. Contour-felled log debris (CFD) and log erosion barriers (LEB) are two techniques used worldwide on hillslopes after wildfires in order to avoid soil erosion. In this context, it is essential to evaluate how these restoration techniques can affect soil properties by increasing or decreasing wildfire impacts. The effects on several physico-chemical and biological soil parameters were here investigated by comparing three differently treated post-fire zones. Three randomly 20 × 20 m distributed plots were set up five years after wildfire in the burned and contour-felled log debris areas (CFD plots), three others in the burned and log erosion barriers area (LEB plots) and three others in the burned and unmanaged plots (BNa plots). Three more plots were set up in an unburned area close to the burned area (UB plots). The results revealed that LEB and, to a lesser extent CFD, improved postfire soil quality, which a priori favoured helped the recovery of ecosystem functions. Our results also indicate greater efficacy of LEB and CFD in retaining sediments by limiting loss of nutrients, which is considered essential to recover vegetation after a wildfire. Post-fire restoration plans should consider the use of LEB and CFD when aiming to favour ecosystem recovery processes after wildfires.


Asunto(s)
Incendios , Incendios Forestales , Ecosistema , Bosques , Suelo
6.
Heliyon ; 10(19): e37948, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39391506

RESUMEN

The escalation of global warming, high temperatures, and wildfire frequency in dry ecosystems, including semi-arid landscapes, has resulted in increased wildfire regimes, compromising ecosystem resistance and resilience. To mitigate these risks, prescribed burning (PB) is being employed as a preventive measure to modify fuel loads in forest ecosystems. However, fire can also impact soil structure and microbiota, which play critical roles in nutrient cycling, biodiversity conservation, and overall ecosystem functioning. Therefore, understanding post-fire processes is essential for sustainable forest management. However, while previous studies have explored the effects of prescribed fire management on semi-arid soil properties in Mediterranean forest ecosystems, gaps remain in our understanding of its specific impact on the physical structure, chemical composition, and biological activities of soils. In this study, we conducted early spring PB in SE Spain in 2021 and assessed the ecological and temporal effects of PB on semi-arid soils. Soil respiration (SR) measurements using automatic CO2 flow chambers were employed to evaluate microbiota recovery. To examine impacts on soil structure we evaluated physicochemical characteristics, soil hydraulic conductivity (SHC), and soil water repellency (SWR). No significant differences were observed in any of the variables studied after one year. However, immediate effects were detected shortly after the PB. Our research specifically targeted soil structure and microbiota in a semi-arid landscape with poor soils, characterized by slower recovery and potentially fragile ecosystems. These results provide valuable insights for forest management practices, indicating that prescribed fire management strategies in similar ecosystems are unlikely to cause adverse effects on soil health. However, further research is warranted to explore the potential effects of prescribed fire intensity and seasonality. Future studies can focus on investigating these factors to provide more targeted recommendations for effective forest management strategies and wildfire prevention efforts.

7.
Sci Total Environ ; 902: 166268, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37595929

RESUMEN

Climate change has led to altered fire patterns in the Mediterranean basin due to rising temperatures and greenhouse gas emissions, diminishing the resilience of forest ecosystems. To address this threat, forest management increasingly employs preventive measures like controlled burns, aiming to mitigate wildfire damage. However, understanding the impact of prescribed burns on vegetation remains crucial. Our study focuses on assessing the ecological effects of early-season prescribed burns on Macrochloa tenacissima communities within Pinus halepensis Mill forests on the Iberian Peninsula. These forests, with southeast-facing slopes and arid soils, heavily rely on alpha grass for post-fire recovery, acting as a shield against runoff and erosion. Yet, the presence of highly flammable resprouting species can lead to rapid combustible material accumulation. We evaluated parameters like coverage, floral diversity (α-diversity), aboveground plant biomass, photosynthetic activity, and chemical leaf properties of alpha grass, a year after a low-intensity controlled burn. Comparing burnt and unburnt areas revealed significant changes in α-diversity and ecophysiology of Macrochloa tenacissima due to early-season prescribed burns. These short-term shifts underscore the need for further exploration of underlying mechanisms. Our analysis also showed distinct shifts in alpha grass leaf chemical composition between the two plot types, potentially impacting post-fire recovery strategies. Although prescribed burning might not be optimal for reducing fire risk in resprouting species-dominated forests, it conserves native plants and enhances ecosystem diversity, providing valuable ecological benefits. In conclusion, our research deepens our understanding of early-season burning's repercussions on flammable vegetation dynamics and combustible material availability in semi-arid landscapes. It contributes to standardized management protocols, aiding effective forest service administration and wildfire risk reduction.


Asunto(s)
Incendios , Pinus , Incendios Forestales , Ecosistema , Poaceae , Plantas
8.
Sci Total Environ ; 855: 159044, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36174695

RESUMEN

Climate change worsening due to global warming and progressive abandonment in rural areas mean that wildfires are increasing in extent and severity terms, and are one of the major disturbances in the Mediterranean Basin. To mitigate these disturbances, preventive management tools need to be used. Fire employment is being implemented, known as prescribed burnings, as forestry actions to change vegetation lines both vertically and horizontally to eliminate forest fuel load continuity. This study aimed to know the ecological effects of late prescribed burning treatments under mixed trees. Prescribed burns were carried out in October 2019 in the municipality of Ayna, Albacete (SE Spain). To assess the short-term (12-month) fire impact on soil, we measured soil respiration with a CO2 flow chamber and analyzed soil physico-chemical properties. We also used minidisc infiltrometers to analyze soil repellency and soil hydraulic conductivity over a 1-year monitoring period. In addition, we evaluated the effects on tree strata by performing chemical nature analyses of fallen needles in Pinus pinaster after prescribed burning. According to our initial hypotheses, the results did not show significant changes in any parameter evaluated during the study period. However, some variables were affected in the first 3 months, needlefall and in microbiological activity, such as variations in soil physico-chemical properties, which can be due to long dry seasons combined with prescribed burning. This study attempts to observe and make known the effects that low-intensity prescribed burning has on soil and needlefall, which are relevant for updating forest management tools.


Asunto(s)
Incendios , Pinus , Suelo/química , Bosques , Agricultura Forestal , Árboles
9.
Disabil Rehabil Assist Technol ; 17(4): 480-486, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-32750254

RESUMEN

MATERIALS AND METHODS: A qualitative approach was employed to track perspectives from a range of patients with chronic lung and/or heart diseases. COPD, IPF and MI outpatients from Denmark and Finland were invited to participate. Data were collected through focus group and semi-structured in-depth interviews. Qualitative analysis was performed using standard thematic analytical approaches. A topic guide was used to explore experiences and perceptions of the ARG telerehabilitation device among participants. RESULTS: Thirteen patients (4 MI, 2 IPF and 7 COPD), 3 women and 10 men aged 56 to 75 years (mean age 63.3 years) were allocated into one focus group (9 patients) and 4 interviews (4 patients). Twelve patients reported the added value of ARG and suggested constructive changes such as the adjustable screen/brightness, robust head fixation for exercise performance, easy to navigate interface and supported feedback based on exercise performance. CONCLUSION: Patients with chronic heart or lung diseases described the added value in an ARG telerehabilitation programme. Improvements for a future version of the ARG were suggested.IMPLICATIONS FOR REHABILITATIONPatients with chronic pulmonary and heart diseases have difficulties to change behaviour to a more active and healthy lifestyle, offers from the health sector to participate in rehabilitation programmes at the hospital are feasible and improves quality of life and exercise capacity. Not all the patients are capable of participating in such rehabilitation programmes due to frailty and long distance to the hospital. Telerehabilitation seems to be a potential treatment to cope with the needs expressed above.Patient involvement in the development of a telerehabilitation solution to empower chronic pulmonary and heart patients to train, ensures a positive contribution to the design of the expected augmented reality software and hardware envisioned solution for telerehabilitation.The development of a user-centered telerehabilitation platform responding to the preferences of patients with chronic disease will remove barriers that limit use and compliance and improve empowerment in future research projects.


Asunto(s)
Realidad Aumentada , Cardiopatías , Enfermedad Pulmonar Obstructiva Crónica , Telerrehabilitación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Motivación , Cooperación del Paciente , Percepción , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Calidad de Vida
10.
Science ; 195(4284): 1353-4, 1977 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-841334

RESUMEN

Uterine smooth muscle cells in "toxemia of pregnancy" contain varying amounts of fat--a feature to date believed to characterize only the arterial smooth muscle cells in atherosclerotic lesions. Thus, the smooth muscle cells at these two sites do not differ essentially in their reactivity to certain forms of injury: hypoxia may represent an injurious factor common to both "toxemia" and atherosclerosis. These observations imply that the view that the arterial smooth muscle cells are biologically different than are those elsewhere may no longer be tenable.


Asunto(s)
Metabolismo de los Lípidos , Miometrio/metabolismo , Preeclampsia/metabolismo , Útero/metabolismo , Arterias/metabolismo , Femenino , Humanos , Miometrio/patología , Preeclampsia/patología , Embarazo
11.
Sci Total Environ ; 671: 776-785, 2019 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-30943444

RESUMEN

Mediterranean basins and their ecosystems have been traditionally affected by wildfires. After a wildfire, check-dam construction in channels is a widespread practice in semi-arid Mediterranean areas as an emergency action to avoid soil erosion. The ways that these structures affect channels' geomorphological and edaphic characteristics or vegetation dynamics, have been widely studied. In relation to vegetation however, the majority of studies have been conducted in mountain torrents. Our approach focuses on how ephemeral streams' vegetation, is affected locally by check-dam construction in the years following a wildfire. Vegetation and soil samplings were carried out in 17 check dams throughout a semiarid area in SE Spain, which was affected by a wildfire in 2012. Check-dams had a significant influence given the accretion of fine sediments in depositional wedges. This accumulation of fine sediments, organic matter and nutrients resulted in the formation of a suitable environment for ruderal plant development by creating a differentiated community upstream of dams. Check-dam construction also affected species diversity, with slightly higher values for the Shannon and Simpson indexes at those transects directly influenced by the structure.


Asunto(s)
Clima , Ecosistema , Monitoreo del Ambiente , Ríos/química , Incendios Forestales , Biodiversidad , Sedimentos Geológicos , Desarrollo de la Planta , Suelo , España
12.
Sci Total Environ ; 654: 441-451, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30447582

RESUMEN

Forest fires-affected landscapes enhance sudden runoff discharges, high sediment loads and extreme soil erosion rates. Different soil stabilisation treatments, such as mulching, can be applied to avoid runoff and soil erosion after wildfires. To characterise the post-fire soil erosion rates and runoff generation, we selected a Mediterranean forest affected by a wildfire in Lietor (Spain) to determine the sediment yield (dry sediment (DS), total suspended sediment (TSS), total dissolved sediment (TDS)) and runoff discharge in twelve 200 m2 (10 × 20 m) plots. Immediately after the wildfire, six plots were covered by straw and six other plots were set up as controls. Three months after the wildfire, logging activities were performed and the experimental designs were as follows: mulching + logging (three replicates), non-mulching + logging (three replicates), non-mulching + non-logging (three replicates) and mulching + non-logging (three replicates). During the period after wildfire and before salvage logging, the straw mulch controlled the soil erosion rates (DS, TSS and TDS) versus the non-mulched plots, but straw had no real impact on runoff discharge. For the period after salvage logging, once again runoff did not differ when comparing all the treatments. DS was higher in the non-mulched and non-logging plots, whereas the highest TSS was found in the non-mulched plots (in logged or non-logged plots). TDS was higher in the mulched and non-logged plots. We conclude that straw mulch is efficient management in recent fire-affected mountainous terrains to control soil loss immediately after wildfire. Moreover, logging operations done 3 months after wildfire did not necessary generate higher DS, TSS, TDS rates, mainly because of the type of machinery used for forest operations.

13.
Sci Total Environ ; 674: 615-622, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31029025

RESUMEN

Fires are a complex phenomenon that may generate a chain of responses and processes that affect each part of the ecosystem. Thus, it is important to understand the magnitude of the impacts of fire on soil properties and the response of plants to this disturbance. For the moment, few studies have examined the effects of prescribed fire on large plots in afforested pine plantations in Mediterranean ecosystems. To fill this gap, the effects of a prescribed fire on runoff, soil erosion, and water quality for approximately one year after burning have been evaluated in pine plantations in south-eastern Spain. We constructed six erosion plots in the control area and six erosion plots in the burned area that were 4 m long and 2 m wide, immediately after the prescribed fire. Runoff, soil erosion and runoff water quality were studied after each rainy event in all plots. Our results reveal that prescribed fire did not significantly affect runoff and soil erosion when low intensity precipitations occur at pine plantations. In relation to water quality, water turbidity, salinity, pH, organic matter content and ionic substances concentrations increased immediately after prescribed burn, nevertheless these changes disappeared over time. We can conclude that prescribed fire can be a useful tool for fuel reduction in Mediterranean pine plantations without wide and long-term impacts to soil losses, or water quality.


Asunto(s)
Agricultura/métodos , Conservación de los Recursos Naturales/métodos , Incendios , Ecosistema , Monitoreo del Ambiente , Granjas , Fenómenos Geológicos , Región Mediterránea , Pinus , Lluvia , Suelo , España , Calidad del Agua
15.
Sci Total Environ ; 642: 117-124, 2018 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-29894870

RESUMEN

Wildfire has historically been an alteration factor in Mediterranean basins. Despite Mediterranean ecosystems' high resilience, wildfire accelerates erosion and degradation processes, and also affects soil functionality by affecting nutrient cycles and soil structure. In semi-arid Mediterranean basins, check dams are usually built in gullies and channels after fire as a measure against soil erosion. Although check dams have proven efficient action to reduce erosion rates, studies about how they affect soil functionality are lacking. Our approach focuses on how soil functionality, defined as a combination of physico-chemical and biological indicators, is locally affected by check dam construction and the evolution of this effect over time. Soils were sampled in eight check dams in two semi-arid areas at SE Spain, which were affected by wildfire in 2012 and 2016. The study findings reveal that by altering sediments cycle and transport, check dams influence soil's main physico-chemical and biochemical characteristics. Significant differences were found between check dam-affected zones and the control ones for many indicators such as organic matter content, electrical conductivity or enzymatic activity. According to the ANOVA results, interaction between check dams influence and time after fire, was a crucial factor. PCA results clearly showed check-dams influence on soil functionality.

16.
Sci Total Environ ; 637-638: 1550-1558, 2018 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-29801248

RESUMEN

Prescribed fires are used as a fuel reduction tool, but heat alter microsite conditions affecting the natural regeneration of Mediterranean pine forests. Our study tested the hypothesis that implementing prescription before or after pine seed release may influence the composition of tree communities by changing the regeneration patterns of Pinus pinaster Aiton across a climatic gradient in the eastern Iberian Peninsula. We ran a seed-sowing experiment to analyse the recruitment patterns of this pine species in prescribed-burned stands, in two different biogeographical seed provenances from wetter and drier areas than the local seeding site. Survival of seedlings was through one year, until the end of the first drought and winter period, respectively. >5400 seeds were sown during the study distributed in sixty plots (30 burned, 30 unburned) per site and treatment, with 10 seeding units per plot. General linear models (GLMs) and ANOVA analyses indicated higher performance for the Drier seed provenance in burned areas, whereas a similar performance was recorded in the control area. Control areas showed higher germination and success rates for plant establishment throughout the study period. Total germination and survival after one year were slightly higher, respectively, at northern sites due to massive mortality during summer in the southern stands. At the burned sites, the mean germination time was significantly longer in those seeds sown before fire passage than those sown after fire. Total germination and successful establishment were significantly higher in the individuals sown before the passage of the fire than in those sown after fire. Most of the mortality occurred in summer for the southern stand, while winter was the most constraining period at the northern sites. The understanding of the dynamics in this species' establishment can help managers to perform a better management planning according to the species' ecology.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Incendios , Bosques , Pinus/fisiología , Quemaduras , Germinación , Plantones , Semillas/fisiología , Árboles/fisiología
17.
Sci Total Environ ; 640-641: 42-51, 2018 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-29852446

RESUMEN

Despite Mediterranean ecosystems' high resilience to fire, both climate and land use change, and alterations in fire regimes increase their vulnerability to fire by affecting the long-term natural recovery of ecosystem services. The objective of this work is to study the effects of fire severity on biochemical soil indicators, such as chemical composition or enzymatic activity, related to time after fire and natural vegetation recovery (soil-plant interphase). Soil samples from three wildfires occurring 3, 15 and 21 years ago were taken in the south-eastern Iberian Peninsula (semiarid climate). Sampling included three fire severity levels in naturally regenerated (and changing to shrublands) Pinus halepensis Mill. forests. In the short-term post-fire period, phosphorus concentration, electrical conductivity and urease activity were positively linked to fire severity, and also influenced ß-glucosidade activity in a negative relationship. During the 15-21-year post-fire period, the effects related to medium-high fire severity were negligible and soil quality indicators were linked to natural regeneration success. The results showed that most soil properties recovered in the long term after fire (21 years). These outcomes will help managers and stakeholders to implement management tools to stabilise soils and to restore burned ecosystems affected by medium-high fire severity. Such knowledge can be considered in adaptive forest management to reduce the negative effects of wildfires and desertification, and to improve the resilience of vulnerable ecosystems in a global change scenario.


Asunto(s)
Monitoreo del Ambiente , Incendios , Bosques , Pinus/química , Suelo/química , Ecosistema
18.
Sci Total Environ ; 644: 247-255, 2018 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-29981973

RESUMEN

Prescribed burnings reduce the biomass and the risk of wildfires but can also alter soil water repellency. The objective of this study is to evaluate the impact of several prescribed burnings in soil water repellency (SWR). In spring 2016, prescribed burns were carried out at three forest sites located in: (i) Beteta in a pure forest of Pinus nigra Arnold ssp. salzmannii; (ii) El Pozuelo in mixed forest stands of Pinus pinaster Aiton and Pinus nigra Arnold ssp. salzmannii; (iii) Lezuza in mixed forest stands of Pinus halepensis Miller and Pinus pinaster Aiton. Six plots were established in each study area: three burned and three unburned. SWR was measured before and immediately after prescribed burns following a 1-year periodic evaluation. There were seven sampling dates at Beteta and El Pozuelo and nine at Lezuza with six plots and six measurement transects in each plot (36 measurement transects on each date). Soil water content (SWC), soil temperature (ST) and soil organic matter (SOM) were also measured. Our results showed that SWR increased after burning to quickly return to normal values in Lezuza, after 1 month in El Pozuelo and after 1 year in Beteta. Moreover, a significant positive relationship between SWR and both SOM and ST, but a negative one with SWC, were observed, which led SWR to increase after fire passage, also in the summer months. Continuous monitoring of these study sites is recommended to determine if low-intensity burnings promote mid- to long-term changes in soil characteristics.


Asunto(s)
Incendios , Bosques , Suelo , Agua , Ecosistema , Pinus
19.
Nat Biotechnol ; 19(11): 1071-3, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11689854

RESUMEN

Mammalian genome characterization and biotechnology each require the mobilization of large DNA segments to produce transgenic animals. We recently showed that mouse metaphase II (mII) oocytes could efficiently promote transgenesis (mII transgenesis) when coinjected with sperm and small (<5 kilobases) ubiquitously expressed transgenes (tgs). We have extended this work and now report that mII transgenesis can readily be applied to a range of larger tgs (11.9-170 kilobases), including bacterial and mammalian artificial chromosome (BAC and MAC) constructs. The efficiency of large-construct mII transgenesis was at least as high as that with small constructs; 11-47% of offspring carried the large tgs. More than 95% of these transgenic founders transmitted the tg to offspring. These data demonstrate the ability of mII transgenesis to deliver large tgs efficiently.


Asunto(s)
Ratones Transgénicos/genética , Animales , Células Cultivadas , Cromosomas Artificiales Bacterianos , Cromosomas Artificiales de los Mamíferos , Desarrollo Embrionario y Fetal , Fertilización In Vitro , Expresión Génica , Técnicas de Transferencia de Gen , Hibridación Fluorescente in Situ , Masculino , Metafase , Ratones , Microinyecciones/métodos , Oocitos/fisiología , Espermatozoides/fisiología , Transgenes
20.
An Otorrinolaringol Ibero Am ; 34(6): 557-64, 2007.
Artículo en Español | MEDLINE | ID: mdl-18293775

RESUMEN

The arterioveinous dural malformation (MAVD) is a rare entity between the vascular craneal anomalies with a not well nown ethiology and variability in treatments. We present eleven cases of MAVDs, between them five presented tinnitus as symptom of aparition. The importance of this pathology makes necessary to discard it before a patient consulting because of pulsaltil tinnitus with normal otoscopy.


Asunto(s)
Malformaciones Arteriovenosas/epidemiología , Enfermedades Otorrinolaringológicas/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Malformaciones Arteriovenosas/diagnóstico , Malformaciones Arteriovenosas/cirugía , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Otorrinolaringológicas/diagnóstico , Enfermedades Otorrinolaringológicas/cirugía
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