961 resultados para Ciencias ambientales


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Se aborda el análisis del área de distribución de una especie con fotosíntesis C4, Atriplex halimus L., a partir de la información corológica existente en el área de Cataluña, Comunidad Valenciana e Islas Baleares, y con la utilización de herramienta SIG, que incluye los factores ambientales considerados como más importantes en la distribución de este tipo de plantas. Este procedimiento representa una alternativa a las investigaciones pasadas en distribución de plantas C4, en este caso se analiza el número de especies C4 en áreas geográficas concretas, a lo largo de gradientes, y es el inicio de una vía más inductiva que puede ser prometedora para entender mejor los factores que afectan a la distribución de estas plantas. Se ha podido obtener un modelo de distribución de A. halimus en base a los factores ambientales actuales que tiene interés porque, aunque el uso de estos métodos predictivos está ya muy extendido, en este caso se aplica por primera vez a una especie que posee una vía de fotosíntesis que ha sido descrita como una adaptación a determinados tipos de clima. En esta especie, la altitud y la precipitación anual, con coeficientes negativos, son las dos variables que al introducirlas, más contribuyen a reducir la desvianza. De las temperaturas consideradas, solo la de enero interviene en el modelo y con un comportamiento diferente por debajo o por encima de los 400 m de altitud. La salinidad del suelo resulta también seleccionada, pero no de forma significativa. La coincidencia entre la distribución real y la resultante de la aplicación del modelo es otro indicador que nos muestra que el modelo es próximo a la realidad, salvo, acaso, en el medio insular. Los resultados son muy coherentes con la información existente sobre los factores que determinan la distribución de las plantas C4 en general, y de las Quenopodiáceas en concreto, que son las temperaturas y el coeficiente de aridez.

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Background. The extraction of salt from seawater by means of coastal solar salterns is a very well-described process. Moreover, the characterization of these environments from ecological, biochemical and microbiological perspectives has become a key focus for many research groups all over the world over the last 20 years. In countries such as Spain, there are several examples of coastal solar salterns (mainly on the Mediterranean coast) and inland solar salterns, from which sodium chloride is obtained for human consumption. However, studies focused on the characterization of inland solar salterns are scarce and both the archaeal diversity and the plant communities inhabiting these environments remain poorly described. Results. Two of the inland solar salterns (termed Redonda and Penalva), located in the Alto Vinalopó Valley (Alicante, Spain), were characterized regarding their geological and physico-chemical characteristics and their archaeal and botanical biodiversity. A preliminary eukaryotic diversity survey was also performed using saline water. The chemical characterization of the brine has revealed that the salted groundwater extracted to fill these inland solar salterns is thalassohaline. The plant communities living in this environment are dominated by Sarcocornia fruticosa (L.) A.J. Scott, Arthrocnemum macrostachyum (Moris) K. Koch, Suaeda vera Forsk. ex Gmelin (Amaranthaceae) and several species of Limonium (Mill) and Tamarix (L). Archaeal diversity was analyzed and compared by polymerase chain reaction (PCR)-based molecular phylogenetic techniques. Most of the sequences recovered from environmental DNA samples are affiliated with haloarchaeal genera such as Haloarcula, Halorubrum, Haloquadratum and Halobacterium, and with an unclassified member of the Halobacteriaceae. The eukaryote Dunaliella was also present in the samples. Conclusions. To our knowledge, this study constitutes the first analysis centered on inland solar salterns located in the southeastern region of Spain. The results obtained revealed that the salt deposits of this region have marine origins. Plant communities typical of salt marshes are present in this ecosystem and members of the Halobacteriaceae family can be easily detected in the microbial populations of these habitats. Possible origins of the haloarchaea detected in this study are discussed.

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In endotherms insects, the thermoregulatory mechanisms modulate heat transfer from the thorax to the abdomen to avoid overheating or cooling in order to obtain a prolonged flight performance. Scarabaeus sacer and S. cicatricosus, two sympatric species with the same habitat and food preferences, showed daily temporal segregation with S. cicatricosus being more active during warmer hours of the day in opposition to S. sacer who avoid it. In the case of S. sacer, their endothermy pattern suggested an adaptive capacity for thorax heat retention. In S. cicatricosus, an active ‘heat exchanger’ mechanism was suggested. However, no empirical evidence had been documented until now. Thermographic sequences recorded during flight performance showed evidence of the existence of both thermoregulatory mechanisms. In S. sacer, infrared sequences showed a possible heat insulator (passive thermal window), which prevents heat transfer from meso- and metathorax to the abdomen during flight. In S. cicatricosus, infrared sequences revealed clear and effective heat flow between the thorax and abdomen (abdominal heat transfer) that should be considered the main mechanism of thermoregulation. This was related to a subsequent increase in abdominal pumping (as a cooling mechanism) during flight. Computer microtomography scanning, anatomical dissections and internal air volume measurements showed two possible heat retention mechanisms for S. sacer; the abdominal air sacs and the development of the internal abdominal sternites that could explain the thermoregulation between thorax and abdomen. Our results suggest that interspecific interactions between sympatric species are regulated by very different mechanisms. These mechanisms create unique thermal niches for the different species, thereby preventing competition and modulating spatio-temporal distribution and the composition of dung beetle assemblages.

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Saproxylic insect communities inhabiting tree hollow microhabitats correspond with large food webs which simultaneously are constituted by multiple types of plant-animal and animal-animal interactions, according to the use of trophic resources (wood- and insect-dependent sub-networks), or to trophic habits or interaction types (xylophagous, saprophagous, xylomycetophagous, predators and commensals). We quantitatively assessed which properties of specialised networks were present in a complex networks involving different interacting types such as saproxylic community, and how they can be organised in trophic food webs. The architecture, interacting patterns and food web composition were evaluated along sub-networks, analysing their implications to network robustness from random and directed extinction simulations. A structure of large and cohesive modules with weakly connected nodes was observed throughout saproxylic sub-networks, composing the main food webs constituting this community. Insect-dependent sub-networks were more modular than wood-dependent sub-networks. Wood-dependent sub-networks presented higher species degree, connectance, links, linkage density, interaction strength, and were less specialised and more aggregated than insect-dependent sub-networks. These attributes defined high network robustness in wood-dependent sub-networks. Finally, our results emphasise the relevance of modularity, differences among interacting types and interrelations among them in modelling the structure of saproxylic communities and in determining their stability.

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Thorectes lusitanicus, a typically coprophagous species is also actively attracted to oak acorns, consuming, burying them, and conferring ecophysiological and reproductive advantages to both the beetle and the tree. In this study, we explored the possible relation between diet shift and the health status of T. lusitanicus using a generalist entomopathogenic fungus (Metarhizium anisopliae) as a natural pathogen. To measure the health condition and immune response of beetles, we analysed the protein content in the haemolymph, prophenoloxidase (proPO) content, phenoloxidase (PO) activity and mortality of beetles with diets based on either acorns or cow dung. Protein content, proPO levels and PO levels in the haemolymph of T. lusitanicus were found to be dependent on the type of diet. Furthermore, the beetles fed with acorns developed a more effective proPO-PO system than the beetles fed with cow dung. Furthermore, a significant decrease in mortality was observed when infected individuals were submitted to an acorn-based diet. In addition to enhancing an understanding of the relevance of dietary change to the evolutionary biology of dung beetles, these results provide a more general understanding of the ecophysiological implications of differential dietary selection in the context of fitness.

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The process of seed dispersal of many animal-dispersed plants is frequently mediated by a small set of biotic agents. However, the contribution that each of these dispersers makes to the overall recruitment may differ largely, with important ecological and management implications for the population viability and dynamics of the species implied in these interactions. In this paper, we compared the relative contribution of two local guilds of scatter-hoarding animals with contrasting metabolic requirements and foraging behaviours (rodents and dung beetles) to the overall recruitment of two Quercus species co-occurring in the forests of southern Spain. For this purpose, we considered not only the quantity of dispersed seeds but also the quality of the seed dispersal process. The suitability for recruitment of the microhabitats where the seeds were deposited was evaluated in a multi-stage demographic approach. The highest rates of seed handling and predation occurred in those microhabitats located under shrubs, mostly due to the foraging activity of rodents. However, the probability of a seed being successfully cached was higher in microhabitats located beneath a tree canopy as a result of the feeding behaviour of beetles. Rodents and beetles showed remarkable differences in their effectiveness as local acorn dispersers. Quantitatively, rodents were much more important than beetles because they dispersed the vast majority of acorns. However, they were qualitatively less effective because they consumed a high proportion of them (over 95%), and seeds were mostly dispersed under shrubs, a less suitable microhabitat for short-term recruitment of the two oak species. Our findings demonstrate that certain species of dung beetles (such as Thorectes lusitanicus), despite being quantitatively less important than rodents, can act as effective local seed dispersers of Mediterranean oak species. Changes in the abundance of beetle populations could thus have profound implications for oak recruitment and community dynamics.

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The wide range of morphological variations in the “loxurina group” makes taxa identification difficult, and despite several reviews, serious taxonomical confusion remains. We make use of DNA data in conjunction with morphological appearance and available information on species distribution to delimit the boundaries of the “loxurina” group species previously established based on morphology. A fragment of 635 base pairs within the mtDNA gene cytochrome oxidase I (COI) was analysed for seven species of the “loxurina group”. Phylogenetic relationships among the included taxa were inferred using maximum parsimony and maximum likelihood methods. Penaincisalia sigsiga (Bálint et al), P. cillutincarae (Draudt), P. atymna (Hewitson) and P. loxurina (C. Felder & R. Felder) were easily delimited as the morphological, geographic and molecular data were congruent. Penaincisalia ludovica (Bálint & Wojtusiak) and P. loxurina astillero (Johnson) represent the same entity and constitute a sub-species of P. loxurina. However, incongruence among morphological, genetic, and geographic data is shown in P. chachapoya (Bálint & Wojtusiak) and P. tegulina (Bálint et al). Our results highlight that an integrative approach is needed to clarify the taxonomy of these neotropical taxa, but more genetic and geographical studies are still required.

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Se presenta el catálogo y análisis de la flora ornamental popular del norte de Alicante, entendiendo por ello, las plantas dispuestas en macetas distribuidas por balcones, umbrales, terrazas, pequeños huertos, etc. La riqueza total del territorio es dos tercios superior, a la de otros estudios de comarcas próximas, superando algunas poblaciones las 200 especies y variedades ornamentales. El elemento autóctono y de introducción antigua es claramente mayoritario, aunque se han observado síntomas recientes de inversión de esta tendencia. Para el mantenimiento de este cultivo tradicional, rico en recursos fitogenéticos, ha quedado patente el papel fundamental de la mujer. Su experiencia acumulada en técnicas y modos de multiplicación y cultivo vegetal han permitido el mantenimiento del paisaje rural autóctono, confiriéndole un valor patrimonial elevado, que debería mantenerse como seña de identidad y calidad, para potenciar el turismo de interior.

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Se presentan varias citas del carraspique leñoso localmente denominado ‘Blanca de l’hivern’ (Iberis semperflorens L.), que no había sido citado expresamente en localidades españolas. Se encuentra principalmente distribuido en el 80% de las poblaciones del Matarraña aragonés, como una importante planta cultivada en macetas de floración invernal. Se ha constatado el cuidado y formas de multiplicación tradicionales, así como el valor de las plantas con más años, que son transferidas como un tesoro entre distintas generaciones de mujeres.

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Cymbalaria aequitriloba (Viv.) A.Chev., es una planta endémica del área Tirrénica (Sicilia, Córcega, Cerdeña y algunos puntos de Italia peninsular), que también alcanza las Islas Baleares. Ha sido encontrada en Torre de Arcas (Teruel) como una planta cultivada o accidental, presente en jardineras de floración invernal, constituyendo un elemento muy particular de la jardinería popular del Matarraña aragonés. Que sepamos, es la primera vez que se cita esta especie en España peninsular. Presenta una gran variabilidad morfológica lo que dificulta su identificación, no obstante es fácilmente diferenciable de C. muralis, la especie más cultivada en la zona. En esta región, tienen por costumbre remover la tierra tras la floración pues la planta pierde belleza, luego vuelve a aparecer en la siguiente estación por renuevo vegetativo o algunas plantas de semilla, motivo que no nos ha permitido estudiar plantas en fructificación. Todo Aragón, pero especialmente el Matarraña, tuvieron estrechos lazos comerciales con Italia durante el s. XIV-XV (principalmente exportando la lana), hecho que pudo favorecer el intercambio de materiales vegetales, como ya se ha podido constatar previamente con otras plantas similares.

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Seven wild and cultivated Salvia species and two Phlomis species, used traditionally in Valencian medicine to treat a variety of external and internal ailments, were studied. New ethnobotanical data are provided, obtained from semistructured interviews with 34 people in the Valencian area. A seasonal characterization of the essential oil of a wild sage, Salvia blancoana Webb & Heldr. subsp. mariolensis Figuerola, by GC-FID and GC-MS was carried out as a means to ensure quality control of endemic traditional species such as this one, which has been commercialized by local industries. A comparison with the essential oil of Salvia lavandulifolia Vahl subsp.lavandulifolia allowed inclusion of the wild sage within the commercial 'Spanish sage' oil.

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Light traps have been used widely to sample insect abundance and diversity, but their performance for sampling scarab beetles in tropical forests based on light source type and sampling hours throughout the night has not been evaluated. The efficiency of mercury-vapour lamps, cool white light and ultraviolet light sources in attracting Dynastinae, Melolonthinae and Rutelinae scarab beetles, and the most adequate period of the night to carry out the sampling was tested in different forest areas of Costa Rica. Our results showed that light source wavelengths and hours of sampling influenced scarab beetle catches. No significant differences were observed in trap performance between the ultraviolet light and mercury-vapour traps, whereas these two methods caught significantly more species richness and abundance than cool white light traps. Species composition also varied between methods. Large differences appear between catches in the sampling period, with the first five hours of the night being more effective than the last five hours. Because of their high efficiency and logistic advantages, we recommend ultraviolet light traps deployed during the first hours of the night as the best sampling method for biodiversity studies of those scarab beetles in tropical forests.

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The valid name for the largest European species of Cetoniinae is Protaetia speciosissima (Scopoli, 1786), with Protaetia aeruginosa (Medvedev, 1964) as a junior synonym. The specimen illustrated by Scopoli in the original description is designated as the lectotype of Scarabaeus speciosissimus Scopoli, 1786. Since the lectotype is lost, a neotype from Piedmont, Italy, is designated and deposited in the Museo Civico di Storia Naturale Carmagnola, Italy. The name Scarabaeus aeruginosus Drury, 1773 is unavailable since Drury did not describe a new species but misidentified Scarabaeus aeruginosus Linné, 1767. A specimen figured by Gronovius in 1764 and cited by Linné is designated as the lectotype of Scarabaeus aeruginosus Linné, 1767. This species remains dubious, but it can be assigned to the ruteline subtribe Anticheirina.

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Unlike other dung beetles, the Iberian geotrupid Thorectes lusitanicus exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.