Regeneración post-incendio de Pinus pinaster Ait. en la Sierra de Guadarrama (Sistema Central, España): modelos descriptivos de los factores influyentes en la densidad inicial y la supervivencia

Natural regeneration of Pinus pinater after wildfire is quite irregular and depends on several unwellknown factors. The objective of this research work is to analyze said process in the forest fire which took place in summer 1999, affecting a total surface of 450 ha, in the Monte Abantos (Sierra de Guadarrama), located in the region of Madrid (Central Spain). This study was carried out in 50 permanent plots, 3 × 3 m size, over the following four years after the fire, collecting data about density, height, slenderness and mortality of the P. pinaster natural regeneration. The final results show that there are a large number of factors which affect seedlings emergency and mortality. A linear pattern that reveals the importance of germination layer physical properties (litter, outcrops and erosion), physiography and interspecific competition, has been obtained. According with the logistical pattern generated, interspecific competition is the most important factor to determine seedlings survival, although physiography, potential forest productivity, basal area, and erosion are also determinant.La regeneración natural post-incendio de Pinus pinaster es bastante irregular dependiendo de numerosos factores no bien conocidos. En este trabajo se pretende analizar dicho proceso en el incendio que tuvo lugar, el verano de 1999, en el Monte Abantos (Sierra de Guadarrama) de la Comunidad de Madrid (Sistema Central, España), con una superficie total afectada de 450 ha. El seguimiento de la densidad, la altura, la esbeltez y la mortalidad del regenerado de P. pinaster, durante los cuatro años siguientes al incendio, se ha llevado a cabo a través de 50 parcelas permanentes de 3 m × 3 m. Los resultados obtenidos revelan la existencia de un elevado número de factores que afectan a la emergencia y la mortalidad de las plántulas. Sí bien, se ha obtenido un modelo lineal que pone de manifiesto el papel fundamental en la emergencia de las características físicas del lecho de germinación (capa de hojarasca y mantillo, pedregosidad y afloramientos, y erosión), la fisiografía y la competencia interespecífica. A su vez este factor es el que más ha condicionado la supervivencia, según el modelo logístico generado, resultando también determinantes la fisiografía, la productividad potencial forestal, el área basal de la masa anterior al incendio y la erosión

Distribución de biomasa y fijación de carbono tras clareos mecanizados intensos en regenerado post-incendio de Pinus pinaster Ait. (Monte «Fraguas», Guadalajara, España)

An experience has been conducted on aPinus pinaster stand in Guadalajara (Central Spain) affected by a wildfire in 1992 to evaluate biomass allocation of different seedling fractions and to quantify the differences between two heavy pine seedling mechanical thinnings. Nine permanent plots (20 m 20 m) were installed in the study area, in 2000. After measuring initial seedling density (10,000 seedlings/ha), a completely randomized block design was used. Three plots remained as control, three were treated with a heavy pine seedling thinning and the other three were treated with a very heavy pine seedling thinning. In each plot, a yearly dasonomic inventory and a biomass destructive inventory every two years, removing 10 representative seedlings of each treatment, were carried out. Multiplicative models (y = axb) have been elaborated in order to relate dasometric variables with the biomass obtained through destructive samplings. The highest correlation coefficients (from 0.80 to 0.97) were obtained for the stem groundline diameter. Results show that biomass accumulation of different seedling fractions is significantly different among treatments, being the increment of C higher with the heaviest thinning. These changes were higher the two first years after thinning. Nevertheless, Carbon sequestration of the stand was significantly higher in the control plots. Consequently, heavy thinning on post-fire Pinus pinaster seedlings makes better their vigour, and decreases forest fire hazard, but at the same time, it produces an important extraction of Carbon sequestrated.Se ha llevado a cabo una experiencia en el monte «Fraguas» (Guadalajara, España) que fue afectado por un incendio en 1992, para evaluar la biomasa acumulada en las diversas fracciones de brinzales post-incendio dePinus pinaster y cuantificar las diferencias observadas como consecuencia de diferentes intervenciones de clareo mecanizado intenso y muy intenso. Se realizó un diseño por bloques al azar estableciendo 9 parcelas permanentes de 20 m x 20 m (3 repeticiones por bloque), en las cuales se llevó a cabo un inventario dendrométrico anual desde 2000 a 2004 y un inventario destructivo de biomasa cada dos años, extrayendo de cada tratamiento 10 pies representativos por clases diamétricas. Se han elaborado modelos de tipo potencial (y = axb) para relacionar las variables dendrométricas con la biomasa obtenida en los muestreos destructivos. Los mejores ajustes se obtuvieron para el diámetro de la base del fuste con los diferentes valores de biomasa (r2 entre 0,80 y 0,97). Los inventarios anuales permitieron establecer la evolución en la fijación de C a lo largo del período de estudio. Los resultados muestran que la biomasa acumulada en las distintas partes del árbol difiere significativamente entre los tratamientos efectuados, obteniendo unos incrementos de C tanto mayores cuanto más intenso fue el tratamiento, sobre todo los dos primeros años. Sin embargo, el C fijado en la masa (t/ha) fue significativamente mayor en el tratamiento testigo. Por tanto, si bien los tratamientos han aumentado el vigor de la masa de porvenir y pueden constituir una práctica interesante desde el punto de vista de la prevención de incendios, provocan una exportación importante de C fijado

Why long term trawled red algae beds off Balearic Islands (western Mediterranean) still persist?

The bottom morphology, the surface sediments and the epibenthic community of two adjacent areas within the fishing ground traditionally known as Pesquera Rica (Balearic Islands) were characterized using multibeam echosounder, van Veen dredge and beam trawl. Red algae beds predominate in both areas, but one has been exploited by trawling since at least 90 years ago, whereas the presence of natural barriers prevents this fishing activity in the other one. Comparisons between the two areas showed a biomass reduction of 46.8 and 39.3% of dominant red algae taxonomic groups Peyssonneliaceae and Corallinophycidae, respectively, in the trawled area (TA). Similarly, both mean abundance and biomass of most groups of fauna were higher in the not trawled area (NTA). N90 biodiversity index showed higher mean values of algae species in NTA than in TA (7.0 and 4.9, respectively), whereas no differences were detected neither for sessile nor for mobile fauna. SIMPER analysis showed that large species of both sessile and mobile epibenthic fauna (e.g. the ascidia Polycarpa mamillaris and the echinoderm Spatangus purpureus, respectively) presented higher abundance and contribution to within area similarity in NTA than in TA. In coincidence, these are the most abundant epibenthic species in the commercial hauls from the Pesquera Rica. The relatively low fishing effort and the gears used, addressed to avoid large catches of algae allowing longer hauls, may explain the subsistence of red algae beds in the Balearic Islands trawl fishing grounds. However, the detrimental effects shown here claim for urgent management measures aiming to preserve these bedsVersión del edito

Declining Population Sizes and Loss of Genetic Diversity in Commercial Fishes: A Simple Method for a First Diagnostic

Exploited fish species may have or are experiencing declines in population sizes coupled with changes in their environmental conditions owing to global change. Declining populations might lead to a decrease in genetic diversity, which in turn may produce losses of adaptive potential to face current and future environmental changes. Thus, this study aims to answer a simple, even naive question, given the complexity of the subject: Could we use a simple method to obtain information on the loss of genetic diversity in exploited fish species? We investigated the use of the levels of genetic diversity in the widely used genetic marker Cytochrome C Oxidase subunit I (COI) mitochondrial gene. Estimates of genetic diversity in COI were obtained for populations of seven fish species with different commercial importance from the East China Sea. These estimates were contrasted against large datasets of genetic diversity in COI for fish species (East-Asian N=118, and worldwide N=1425), and six control species with known biology and history. We found that estimates of genetic diversity in COI match the expectations from theoretical predictions and known declines by fishing pressures. Thus, the answer to our question is affirmative and we conclude that estimates of genetic diversity in COI provide an effective first diagnostic of the conservation status of exploited fish species.En prens

Submillimetre compactness as a critical dimension to understand the main sequence of star-forming galaxies

We study the interstellar medium (ISM) properties as a function of the molecular gas size for 77 infrared-selected galaxies at z ∼ 1.3, having stellar masses 109.4 ≲ M⋆ ≲ 1012.0 M⊙ and star formation rates 12 ≲ SFRFIR ≲ 1000 M⊙ yr−1. Molecular gas sizes are measured on ALMA images that combine CO(2-1), CO(5-4), and underlying continuum observations, and include CO(4-3), CO(7-6) + [CI](3P2 − 3P1), [CI](3P1 − 3P0) observations for a subset of the sample. The ≳46 per cent of our galaxies have a compact molecular gas reservoir, and lie below the optical discs mass–size relation. Compact galaxies on and above the main sequence have higher CO excitation and star formation efficiency than galaxies with extended molecular gas reservoirs, as traced by CO(5-4)/CO(2-1) and CO(2-1)/LIR, SF ratios. Average CO + [CI] spectral line energy distributions indicate higher excitation in compacts relative to extended sources. Using CO(2-1) and dust masses as molecular gas mass tracers, and conversion factors tailored to their ISM conditions, we measure lower gas fractions in compact main-sequence galaxies compared to extended sources. We suggest that the submillimetre compactness, defined as the ratio between the molecular gas and the stellar size, is an unavoidable information to be used with the main sequence offset to describe the ISM properties of galaxies, at least above M⋆ ≥ 1010.6 M⊙, where our observations fully probe the main sequence scatter. Our results are consistent with mergers driving the gas in the nuclear regions, enhancing the CO excitation and star formation efficiency. Compact main-sequence galaxies are consistent with being an early post-starburst population following a merger-driven starburst episode, stressing the important role of mergers in the evolution of massive galaxies

Synthesis of Nitrogenated Heterocycles by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)haloimines

Highly optically enriched, protected, nitrogenated heterocycles with different ring sizes have been synthesized by a very efficient methodology consisting of the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)haloimines followed by treatment with a base to promote an intramolecular nucleophilic substitution process. N-Protected aziridines, pyrrolidines, piperidines, and azepanes bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and diastereomeric ratios up to >99:1. The free heterocycles can be easily obtained by a simple and mild desulfinylation procedure. Both enantiomers of the free heterocycles can be prepared with the same good results by changing the absolute configuration of the sulfur atom of the sulfinyl group.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; grant no. CONSOLIDER INGENIO 2010, CSD2007-00006, CTQ2007-65218 and CTQ2011-24151) and the Generalitat Valenciana (PROMETEO/2009/039 and FEDER). O.P. thanks the Spanish Ministerio de Educación for a predoctoral fellowship (grant no. AP-2008-00989)

GOODS-ALMA 2.0: Last gigayear star formation histories of the so-called starbursts within the main sequence

Recently, a population of compact main sequence (MS) galaxies exhibiting starburst-like properties have been identified in the GOODS-ALMA blind survey at 1.1mm. Several evolution scenarios were proposed to explain their particular physical properties (e.g., compact size, low gas content, short depletion time). In this work, we aim at studying the star formation history (SFH) of the GOODS-ALMA galaxies to understand if the so-called ``starburst (SB) in the MS'' galaxies exhibit a different star formation activity over the last Gyr compared to MS galaxies that could explain their specificity. We use the CIGALE SED modelling code to which we add non-parametric SFHs. To compare quantitatively the recent SFH of the galaxies, we define a parameter, the star formation rate (SFR) gradient that provides the angle showing the direction that a galaxy has followed in the SFR vs stellar mass plane over a given period. We show that ``SB in the MS'' have positive or weak negative gradients over the last 100, 300, and 1000 Myr, at odds with a scenario where these galaxies would be transitioning from the SB region at the end of a strong starburst phase. Normal GOODS-ALMA galaxies and ``SB in the MS'' have the same SFR gradients distributions meaning that they have similar recent SFH, despite their different properties (compactness, low depletion time). The ``SBs in the MS'' manage to maintain a star-formation activity allowing them to stay within the MS. This points toward a diversity of galaxies within a complex MS.Comment: Submitted to A&

Issues related to the MEDITS reference list of species

The MEDITS survey programme started in 1994 and adopted the basic protocols by the four first partners, just before the first survey. These protocols included the design of the survey, the sampling gear, the information collected, and the management of the data as far as the production of common standardized analyses of the data (Bertrand et al., 2002). The last updating of protocols has been done in 2007 (MEDITS, 2007). According to it, for each species the total weight and number of individuals is recorded. For a reference list of 38 species of fish, crustaceans and cephalopods, the length frequency by sex must be reported, as well as the maturity stage of the gonads. However, two different things should be taken into account. On one hand, for most works performed using MEDITS data (including assessments), the length frequency distributions are used, without taking into account the sex. On the other hand, the period of the surveys is not always coincident with the spawning season for all the species in the MEDITS reference list. This document attempts to be a practical exercise in relation to these topics, using both surveys and commercial data, and gives some proposals to the reference list of specie