Biological significance of dead biomass retention trait in Mediterranean Basin species: an analysis between different successional niches and regeneration strategies as functional groups

Standing dead biomass retention is considered one of the most relevant fuel structural traits to affect plant flammability. However, very little is known about the biological significance of this trait and its distribution between different functional groups. Our aim was to analyse how the proportion of dead biomass produced in Mediterranean species is related to the successional niche of species (early-, mid- and late-successional stages) and the regeneration strategy of species (seeders and resprouters). We evaluated biomass distribution by size classes and standing dead biomass retention in nine dominant species from the Mediterranean Basin in different development stages (5, 9, 14 and 26 years since the last fire). The results revealed significant differences in the standing dead biomass retention of species that presented a distinct successional niche or regeneration strategy. These differences were restricted to the oldest ages studied (>9 years). Tree and small tree resprouters, typical in late-successional stages, presented slight variations with age and a less marked trend to retain dead biomass, while seeder shrubs and dwarf shrubs, characteristic of early-successional stages, showed high dead biomass loads. Our results suggest that the species that tend to retain more dead branches are colonising species that may promote fire in early-successional stages.This research has been partially financed by programme FORESTERRA ERA-Net (Medwildfirelab, PCIN-2013-140-C04-03), PROMETEO II (Desestrés/2014/038) and the Spanish Ministry of Education (Resilience CGL 2011-30515-C02-02). CEAM is supported by the Generalitat Valenciana (Regional Valencian Government)

Relationship between membrane vesicles, extracellular ATP and biofilm formation in Antarctic Gram-negative bacteria

Biofilms offer a safe environment that favors bacterial survival; for this reason, most pathogenic and environmental bacteria live integrated in biofilm communities. The development of biofilms is complex and involves many factors, which need to be studied in order to understand bacterial behavior and control biofilm formation when necessary. We used a collection of cold-adapted Antarctic Gram-negative bacteria to study whether their ability to form biofilms is associated with a capacity to produce membrane vesicles and secrete extracellular ATP. In most of the studied strains, no correlation was found between biofilm formation and these two factors. Only Shewanella vesiculosa M7T secreted high levels of extracellular ATP, and its membrane vesicles caused a significant increase in the speed and amount of biofilm formation. In this strain, an important portion of the exogenous ATP was contained in membrane vesicles, where it was protected from apyrase treatment. These results confirm that ATP influences biofilm formation. Although the role of extracellular ATP in prokaryotes is still not well understood, the metabolic cost of its production suggests it has an important function, such as a role in biofilm formation. Thus, the liberation of extracellular ATP through membrane vesicles and its function deserve further study

Dialogamos de sexo en la escuela

Proyecto interdisciplinario de Educación Sexual desarrollado a traves de talleres en todos los años y divisiones de la Escuela normal "Ramón J. Cárcano" de la Ciudad de Monte Caseros, Corrientes durante el ciclo lectivo 2008 . La áreas involucradas fuerosn Ciencias Naturales,Educación Física,Educación Artística y Matematica. Se realizó un diagnóstico a partir de una encuasta anónima individual a cada alumno participante de los talleres, la misma nos sirvió pra trabajar preconceptos sobre Educación Sexual que poseen los alumnos. A partir de alli se realizarón varios encuentros donde a través de juegos de comunicación , de contacto corporal con música figuras ,representaciones se abordaron contenidos conceptuales ,procedimentales y actitudinales que permiten educacar en sexualidad apuntando al desarrollo integral del individuo

Testing the Role of Male-Male Competition in the Evolution of Sexual Dimorphism: A Comparison Between Two Species of Porcelain Crabs

Theory predicts marked sexual dimorphism in terms of body size and body structures used as weapons (e.g. chelipeds) in gonochoric species with intense male sexual competition for receptive females and reduced or no sexual dimorphism in species where competition among males is trivial. We tested this hypothesis using a pair of closely-related species of symbiotic porcelain crabs as a model. In one species that inhabits sea anemones solitarily, competition among males for receptive females is unimportant. In a second species that dwells as dense aggregations on sea urchins, malemale competition for sexual partners is recurrent. We expected considerable sexual dimorphism in body size and weaponry in the urchin-dwelling crab and reduced sexual dimorphism in the anemone-dwelling crab. In agreement with expectations, in the urchin-dwelling crab, male body size was, on average, larger than that of females and males invested considerably more to cheliped length than females. Also supporting theoretical considerations, in the anemone-dwelling crab, sexual dimorphism in terms of body size was not detected and differences between the sexes in investment to cheliped length were minor. Interestingly, chelipeds were more developed both in males and females of the anemone-dwelling crab than in the urchin-dwelling crab as a result of the importance of these structures for monopolization of their naturally scarce anemone hosts. Another difference between the studied species was the existence of two clearly distinguishable ontogenetic phases in males of the urchin-dwelling crab but not in males of the anemone-dwelling crab. Whether the two different male morphs display different male reproductive strategies in the urchin-dwelling crab remains to be addressed. Other conditions that might additionally explain the observed differences in sexual dimorphism (e.g. female mate choice) between the studied species remain to be explored. © 2011 The Linnean Society of London

Environmental and anthropogenic drivers of coniferous species distribution in Mediterranean drylands from North West Algeria

Understanding the influence of environmental and anthropogenic factors on the distribution of species is essential for developing management in endangered ecosystems. We studied the current abundance and distribution patterns of vegetation along environmental and anthropogenic gradients in North West Algeria. We focused on the four dominant coniferous species (Pinus halepensis, Tetraclinis articulata, Juniperus oxycedrus and Juniperus phoenicea). We compiled inventories of species composition, together with 12 environmental variables in 177 sampling plots throughout the study area. Multivariate (detrended correspondence analysis) and univariate (Huisman–Olf–Fresco models) analyses were applied to predict the presence of coniferous species and to explore species-environment relationships with ecological and anthropogenic variables. We found that species segregated along environmental gradients, mainly altitude and related climatic variables (temperatures). Anthropogenic variables, like fire frequency and overgrazing, were secondary, but also significant. Juniperus phoenicea was located exclusively in coastal areas. Tetraclinis articulata had a wide distribution and was linked to coastal and inland areas, but did not arrive at more continental areas (colder and drier), where it was replaced with J. oxycedrus. P. halepensis displayed the widest distribution and was practically present throughout the study area, but its maximum abundance was in continental areas. These results indicate a possible shift of species’ potential distribution in future climatic change. Species like J. oxycedrus would be seriously threatened by niche narrowing, while Pinus halepensis and T. articulata could expand to a certain extent. Our results provide important inputs for optimizing the management plans of coniferous species by considering environmental factors key modulators of vegetation distribution.This work has been conducted as part of the Research Integrated Action Programme TASSILI ‘History of woody vegetation and associated biodiversity conservation in north west Algeria’ (2007, No. 07MDU703). Faouzia Ayache was supported through a MAEC-AECID grant from the Spanish Agency for International Cooperation and Development. V.M. Santana was supported by a ‘Beatriu de Pinós’ grant (2014BP-2014BPB00056) Generalitat de Cataluña and M.J. Baeza was supported by the SURVIVE-2 (CGL2015-69773-C2-2-P) project

Allometric equations to calculate living and dead fuel loads in Mediterranean species

Determining the structure and fuel load is key to know the flammability of vegetation in the Mediterranean Basin where forest fires are frequent. Determine which plant structural variable is best related to living and dead fuel to develop allometric equations in nine species in the Western Mediterranean Basin. In the east of the Iberian Peninsula (Valencia Province), we measured four structural variables (basal stem diameter, height, maximum diameter and perpendicular diameter) that were related, by means of allometric equations, to the living and dead fuel separated into different size classes. We also analyze fuel changes across developmental states of the studied species, and the vertical distribution of dead fuel. General equations that consider all development states can be used to determine living fuel. However to obtain dead fuel, we recommend using specific equations for each development state and fuel fraction for better accuracy. The basal stem diameter was the best structural variable in almost all cases for estimating fuel in the studied species. Dead fuel load throughout species’ ontological development is a key factor to manage Mediterranean plant communities.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the HYDROMED project funded by the Spanish Ministry of Science and Innovation (Subprojects BLUEWATER PID2019-111332RB-C21 and INERTIA PID2019-111332RB-C22), IMAGINA (PROMETEO/2019/110) and the FIRE-SCENARIO (GV-2020-160) projects funded by the Generalitat Valenciana

Análisis espacial del patio en la vivienda mexicalense

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