Spatial Gradients of Intensity and Persistence of Soil Water Repellency Under Different Forest Types in Central Mexico

Organic residues release hydrophobic compounds to the soil that may induce soil water repellency (WR), which may inhibit infiltration andincrease runoff and soil loss rates. Although there are many studies on soil WR through the world, very few investigations have been con-ducted in Mexican areas. This paper studies the natural background of soil WR in soils from central Mexico under representative forest types,analyzing the spatial distribution of soil WR in relation with tree canopy, vegetation cover and main soil chemical (pH, CaCO3, organic Ccontent and exchangeable cations) and physical properties (texture). The water drop penetration time and the ethanol tests were used to assesspersistence and intensity of soil WR, respectively. Although soil WR was not related with soil properties, it decreased strongly from soil be-low the canopy of conifers to soil below oaks. When different types of vegetation cover were considered, the proportion of water-repellentsoil increased following the sequence: bare soil < shrubs and herbaceous plants < shrubs < trees from fir, fir-pine-oak and pine-oak forest.We found an inverse relation with distance to the tree trunks, contributing to create a patchy pattern of soil WR, with soils under the canopyof conifers showing the most severe WR levels. The spatial distribution of soil WR is also conditioned by microclimatic gradients, as per-sistence and intensity of soil WR were usually lower in shaded areas (upslope transects from the tree trunks), where soil moisture contentis expected to be higher on average through the year. Copyright © 2016 John Wiley & Sons, LtdMinisterio de Economía y Competitividad CGL2013-47862-C2-1-RMinisterio de Economía y Competitividad CGL 2012-38655-C04-0

Stones resting on the top soil cause heterogeneous patterns of fire-induced water repellency

Depending on soil and fire characteristics, soil water repellency (SWR) may be induced, enhanced or destroyed by burning. The spatial pattern of SWR may be extremely heterogeneous as a consequence of the temperature peaks, the variation of fire temperature, the distribution of fuel, or the amount and type of ashes. In this research, we have studied the effect of stone cover and position on the intensity and spatial distribution of fire-induced SWR after low-, moderate- and high-severity fire. Generally, SWR increased with fire severity, but stones did induce some differences and increased the heterogeneity of the spatial distribution of fire-induced SWR. In low-stone-cover areas, SWR from soil surfaces below stones increased respect to non-covered soil surfaces. In areas under high stone cover, SWR increased from non-covered soil surfaces to soil surfaces below stones after low-severity fire. In moderate- and high-severity burnt soils under high stone cover, SWR was more severe than in non-covered soil surface, but no significant differences were observed.Ministerio de Economía y Competitividad CGL2010-21670-C02-0

Patterns and drivers of tree Mortality in Iberian Forests: climatic effects are modified by competition

Tree mortality is a key process underlying forest dynamics and community assembly. Understanding how tree mortality is driven by simultaneous drivers is needed to evaluate potential effects of climate change on forest composition. Using repeat-measure information fromc.400,000 trees from the Spanish Forest Inventory, we quantified the relative importance of tree size, competition, climate and edaphic conditions on tree mortality of 11 species, and explored the combined effect of climate and competition. Tree mortality was affected by all of these multiple drivers, especially tree size and asymmetric competition, and strong interactions between climate and competition were found. All species showed L-shaped mortality patterns (i.e. showed decreasing mortality with tree size), but pines were more sensitive to asymmetric competition than broadleaved species. Among climatic variables, the negative effect of temperature on tree mortality was much larger than the effect of precipitation. Moreover, the effect of climate (mean annual temperature and annual precipitation) on tree mortality was aggravated at high competition levels for all species, but especially for broadleaved species. The significant interaction between climate and competition on tree mortality indicated that global change in Mediterranean regions, causing hotter and drier conditions and denser stands, could lead to profound effects on forest structure and composition. Therefore, to evaluate the potential effects of climatic change on tree mortality, forest structure must be considered, since two systems of similar composition but different structure could radically differ in their response to climatic conditions

Implementation tells us more beyond pooled estimates: Secondary analysis of a multicountry mhealth trial to reduce blood pressure

Background: The uptake of an intervention aimed at improving health-related lifestyles may be influenced by the participant’s stage of readiness to change behaviors. Objective: We conducted secondary analysis of the Grupo de Investigación en Salud Móvil en América Latina (GISMAL) trial according to levels of uptake of intervention (dose-response) to explore outcomes by country, in order to verify the consistency of the trial’s pooled results, and by each participant’s stage of readiness to change a given lifestyle at baseline. The rationale for this secondary analysis is motivated by the original design of the GISMAL study that was independently powered for the primary outcome—blood pressure—for each country. Methods: We conducted a secondary analysis of a mobile health (mHealth) multicountry trial conducted in Argentina, Guatemala, and Peru. The intervention consisted of monthly motivational phone calls by a trained nutritionist and weekly tailored text messages (short message service), over a 12-month period, aimed to enact change on 4 health-related behaviors: salt added to foods when cooking, consumption of high-fat and high-sugar foods, consumption of fruits or vegetables, and practice of physical activity. Results were stratified by country and by participants’ stage of readiness to change (precontemplation or contemplation; preparation or action; or maintenance) at baseline. Exposure (intervention uptake) was the level of intervention (<50%, 50%-74%, and ≥75%) received by the participant in terms of phone calls. Linear regressions were performed to model the outcomes of interest, presented as standardized mean values of the following: blood pressure, body weight, body mass index, waist circumference, physical activity, and the 4 health-related behaviors. Results: For each outcome of interest, considering the intervention uptake, the magnitude and direction of the intervention effect differed by country and by participants’ stage of readiness to change at baseline. Among those in the high intervention uptake category, reductions in systolic blood pressure were only achieved in Peru, whereas fruit and vegetable consumption also showed reductions among those who were at the maintenance stage at baseline in Argentina and Guatemala. Conclusions: Designing interventions oriented toward improving health-related lifestyle behaviors may benefit from recognizing baseline readiness to change and issues in implementation uptake.Fil: Carrillo-Larco, Rodrigo M.. Universidad Peruana Cayetano Heredia; Perú. Imperial College London; Reino UnidoFil: Jiwani, Safia S.. Universidad Peruana Cayetano Heredia; PerúFil: Diez Canseco, Francisco. Universidad Peruana Cayetano Heredia; PerúFil: Kanter, Rebecca. Institute of Nutrition of Central America and Panama; Guatemala. Universidad de Chile; ChileFil: Beratarrechea, Andrea Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institute for Clinical Effectiveness and Health Policy; ArgentinaFil: Irazola, Vilma. Institute for Clinical Effectiveness and Health Policy; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramirez Zea, Manuel. Institute of Nutrition of Central America and Panama; GuatemalaFil: Rubinstein, Adolfo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Martinez, Homero. Nutrition International; Canadá. Hospital Infantil de Mexico Federico Gomez; MéxicoFil: Miranda, J. Jaime. Cronicas Centro de Excelencia En Enfermedades Crónicas; Perú. Universidad Peruana Cayetano Heredia; PerúFil: Alasino, Adrían. Funprecal; ArgentinaFil: Budiel Moscoso, Berneth Nuris. Universidad Peruana Cayetano Heredia; PerúFil: Carrara, Carolina. Instituto Universitario del Hospital Italiano de Buenos Aires; ArgentinaFil: Espinoza Surichaqui, Jackelyn. Universidad Peruana Cayetano Heredia; PerúFil: Giardini, Gimena. Instituto Universitario del Hospital Italiano de Buenos Aires; ArgentinaFil: Guevara, Jesica. Institute of Nutrition of Central America And Panama Guatemala; GuatemalaFil: Morales Juárez, Analí. Institute of Nutrition of Central America And Panama Guatemala; GuatemalaFil: Lázaro Cuesta, Lorena. Funprecal; ArgentinaFil: Lewitan, Dalia. Institute For Clinical Effectiveness And Health Policy; ArgentinaFil: Palomares Estrada, Lita. Universidad Peruana Cayetano Heredia; PerúFil: Martínez Ramírez, Carla. Universidad Peruana Cayetano Heredia; PerúFil: de la Cruz, Gloria Robles. Universidad Peruana Cayetano Heredia; PerúFil: Salguero, Julissa. Institute Of Nutrition Of Central America And Panama Guatemala; GuatemalaFil: Saravia Drago, Juan Carlos. Universidad Peruana Cayetano Heredia; PerúFil: Urtasún, María. Institute For Clinical Effectiveness And Health Policy; ArgentinaFil: Zavala Loayza, José Alfredo. Universidad Peruana Cayetano Heredia; Per

Crisis neoliberal y la formulación de nuevas teorías sociales. Valor compartido y Buen vivir

Objetivo: identificar la repercusión que tienen las crisis generadas por el sistema neoliberal en la construcción epistemológica de las Ciencias Sociales.Metodología: investigación cualitativa en la que se utilizó el trabajo documental y el método hermenéutico con base, principalmente, en una lectura diacrónica de los documentos y en el análisis crítico de éstos. Las categorías en las que se centró el estudio fueron: “crisis del sistema neoliberal”, “movimientos sociales anti neoliberales” y “giro epistemológico”. Resultados: las luchas y demandas populares generadas por las limitaciones del sistema neoliberal repercuten en las reflexiones y formulaciones teóricas en el continente americano. Conceptual o científicamente se están desarrollando teorías sociales que proponen otras estrategias de organización social. Conclusiones: se concluye que las fracturas o cambios en la estructura social del sistema impactan el pensar teórico y la construcción del conocimiento científico. La crisis financiera de 2008 en Estados Unidos generó una serie de movilizaciones sociales que surgieron como protesta ante los desajustes económicos y de empleo que desencadenó dicha crisis. En el caso de Latinoamérica, las limitaciones del sistema neoliberal para generar una adecuada calidad de vida en la población provocaron el surgimiento de movimientos antineoliberales en Ecuador, Venezuela, Bolivia y México; los cuales –excluyendo el caso mexicano– se instauraron como hegemónicos en los países donde ocurrieron. Los procesos políticos, sociales y económicos que surgieron en Norteamérica y en Latinoamérica impactaron en la construcción teórica y en la episteme predominante.

How wildfires affect soil properties. A brief review

Wildfires may produce several changes in the short- and longterm in the landscape and in the soil system. The magnitude of these changes induced by fire in the components of ecosystems (water, soil, vegetation and fauna) depends on fire properties (fire intensity and severity) and environmental factors (vegetation, soil, geomorphology, etc.). The most important impacts on soils in the short-term are the reduction of vegetation cover (which increases soil erosion risk), the deposition of ash after combustion of biomass, the induction of enhancement of water repellency and changes in the structure and soil components. Combustion of biomass and soil organic matter also results in the release of gases and other pollutants into the atmosphere. Similarly, the changes induced by fire on the biological soil components (vegetation, animals and soil microorganisms) may occur rapidly and produce a large-scale response. The long-term effects of fire on soils and water may well persist for relatively short periods (hours, days or months), long (years or tens of years), or be permanent depending on the severity of fire and fire regime. Some of these effects are a consequence of the relationship between fire, soil, hydrology and nutrient cyclingLos incendios forestales pueden producir varios cambios a corto y largo plazo en el paisaje y en el sistema suelo. La magnitud de estos cambios inducidos por el fuego en los componentes de los ecosistemas (agua, suelo, vegetación y fauna) depende de las propiedades del incendio (intensidad y severidad del fuego) y ambientales (vegetación, suelos, geomorfología, etc.) Los impactos más importantes de los suelos en el corto plazo son la reducción de la cubierta vegetal (que aumenta el riesgo de erosión del suelo), la deposición de cenizas después de la combustión de la biomasa, la inducción de la mejora de la repelencia al agua y los cambios en la estructura y componentes del suelo. La combustión de la materia orgánica del suelo y la biomasa también se traduce en la emisión de gases y otros contaminantes a la atmósfera. Del mismo modo, los cambios inducidos por el fuego en los componentes biológicos del suelo (vegetación, animales y microorganismos del suelo) pueden ocurrir rápidamente y producir una respuesta a gran escala. Los efectos a largo plazo de los incendios en los suelos y el agua y pueden persistir durante períodos relativamente cortos (horas, días o meses), largos (años o decenas de años), o ser permanente dependiendo de la severidad del fuego y el régimen de incendios. Algunos de estos efectos son una consecuencia de la relación entre el fuego, la hidrología y el ciclo de nutrientes

Small variations in soil properties control fire-induced water repellency.

Fire induced soil water repellency (WR) is controlled by many different factors (temperature reached, amount and type of fuel, etc.). Soil properties may determine the occurrence and intensity of this property in burned soils. The objectives of this paper are to make advances in the study of soil properties as key factors controlling the behaviour of fire-induced WR, and to study the impact of pre-fire SOM content and SOM quality in fire-induced soil WR. In this research, experimental laboratory burnings were carried out using soil samples from different sites with different lithologies, soil types and plant species. Soil samples from the same site differ only in quantity and quality of soil organic matter, as they were collected from under different plant species. All soil samples were heated in a muffle furnace at 200, 250, 300 and 350 ºC without the addition of any fuel load. WR was measured using the water drop penetration time test (WDPT). The results showed significant differences between soil types and plant species, indicating that small differences in soil properties may act as key factors controlling the development and persistence of WR reached, with burned soil samples ranging from wettable to extremely water repellent. The main soil property controlling the response was texture, specifically sand content. The quality of organic matter was also observed to have an effect, since soil samples from the same site with similar organic matter contents, but collected from beneath different plant species, showed different WR values after burning.A repelência à água (WR) induzida no solo pelo fogo é uma propriedade controlada por diversos fatores (temperatura atingida, quantidade e tipo de combustível, etc.). Algumas propriedades podem determinar a presença e intensidade da WR nos solos afetados pelo fogo. O objetivo deste artigo é demonstrar os últimos avanços no estudo das propriedades do solo, como factores chave, que controlam o comportamento da hidrofobicidade induzida pelo fogo, o impacto do conteúdo de matéria orgânica pré-fogo e a qualidade da matéria orgânica em solos afetados por repelência pós-incêndio. Neste estudo, foram realizadas queimadas controladas em laboratório, utilizando amostras de solo de locais com diferentes substratos litológicos e com diferentes tipos de solo, colonizados por diferentes espécies vegetais. As amostras recolhidas em diferentes locais diferem nalgumas propriedades do solo, enquanto as amostras de solo recolhidas no mesmo local apenas diferem na quantidade e qualidade da matéria orgânica, dado que foram recolhidas em áreas colonizadas por diferentes espécies de plantas. Todas as amostras foram submetidas às temperaturas de 200, 250, 300 e 350 °C num forno. A WR foi medida através do teste da gota de água (WDPT). Os resultados mostraram diferenças significativas entre os tipos de solos e plantas estudadas. Observaram-se pequenas diferenças em algumas propriedades do solo, que podem atuar como fatores-chave que controlam o desenvolvimento e persistência da WR nos solos queimados, que variam entre o hidrofílico e o extremamente repelente à água. A propriedade que mais influencia o comportamento da WR é a textura, especialmente o teor em areia. Por outro lado, observou-se que a qualidade da matéria orgânica também afetou a WR, dado que em amostras de solo recolhidas no mesmo local e com conteúdo em matéria orgânica semelhante, mas recolhidas em solos colonizados por diferentes espécies de plantas, mostraram valores muito diferentes de repelência à água após a queimada.La repelencia al agua (WR) inducida por el fuego es una propiedad controlada por muchos factores diferentes (temperaturas alcanzadas, cantidad y tipo de combustible, etc.). Algunas propiedades del suelo pueden determinar la presencia y la intensidad de esta propiedad en los suelos quemados. Los objetivos principales son: avanzar en el estudio de la influencia de algunas propiedades clave en el control del comportamiento de la WR en suelos quemados, así como estudiar la influencia de la cantidad y la calidad de la materia orgánica del suelo en su desarrollo cuando es afectada por el calentamiento. En éste estudio, hemos realizado quemas controladas en laboratorio utilizando muestras de suelo de diferentes sitios con litologías y tipos de suelos diferentes y recogidas bajo distintas especies vegetales. Las muestras recogidas en diferentes sitios difieren en algunas propiedades del suelo, mientras que las muestras de suelo tomadas del mismo sitio sólo se diferencian en la cantidad y la calidad de la materia orgánica del suelo, ya que se recogieron bajo distintas especies de plantas. Todas las muestras de suelo se calentaron en horno de mufla a 200, 250, 300 y 350 ºC. La repelencia al agua se midió mediante el test del tiempo de penetración de la gota de agua (WDPT). Los resultados mostraron diferencias significativas entre los tipos de suelos y especies vegetales, y se comprobó que pequeñas diferencias en algunas propiedades del suelo pueden actuar como factores clave controlando el desarrollo y persistencia de la repelencia al agua, con muestras de suelo quemadas que variaban entre hidrofílicas a extremadamente repelentes al agua. La propiedad que principalmente controló el comportamiento de la repelencia al calentamiento fue la textura y más concretamente el contenido de arena. Por otro lado se observó que la calidad de la materia orgánica también afecta, ya que muestras de suelo de mismo sitio y con contenido de materia orgánica similar, pero tomadas bajo diferentes especies vegetales mostraron valores muy diferentes de repelencia al agua tras la quema