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Almería, Spain

Miralles I.,EEZA | Trasar-Cepeda C.,CSIC - National Institute of Agrobiological Sciences | Leiros M.C.,University of Santiago de Compostela | Gil-Sotres F.,University of Santiago de Compostela
Soil Biology and Biochemistry

Decomposition processes are extremely important in biological soil crusts (BSCs). Although the effects of temperature and moisture on such processes have been widely studied, little is known about the influence of the readily metabolizable substrate (labile C) and how this substrate varies in different types of BSCs. In the present study, BSCs formed by cyanobacteria (CYANO) and by lichens (DIPLOS and LEPRA) were incubated at 25 °C (optimum temperature) and different moisture levels, for evaluation of the pool of labile C in the crust layers. Labile C was estimated as the sum of CO2-C emitted and the C extracted with hot water (80 °C) at the end of the incubation period. In all crusts, the relationship between emission and moisture fitted a quadratic model. For the different moisture contents, the sum of CO2-C emitted and C extracted with hot water converged to a constant value for each type of crust. This value, considered as the maximum content of labile C in the crust, was extremely high in DIPLOS, reaching up to 40% of the total organic C (TOC) initially present. In all crusts, and independently of the consumption of labile C, simple sugars (sucrose, glucose) remained at the end of the incubation period, which suggests that these sugars may play a protective role in BSCs. The presence of mannitol suggests that the fructose released during hydrolysis of sucrose was reduced to mannitol, thus enabling electron transport during moments of intense respiratory stress. The intense respiration in DIPLOS is partly due to the metabolism of polyphenols, which are possibly derived from the growth and death of free-living fungi that proliferate during incubation of the crusts. These results demonstrate that the metabolic processes in BSCs differ depending on the type of organisms that form the crusts and that there is a high risk of C loss from Diploschistes BSCs after heavy rainfall events. © 2012 Elsevier Ltd. Source

Grubb P.J.,University of Cambridge | Maranon T.,IRNAS | Pugnaire F.I.,EEZA | Sack L.,University of California at Los Angeles
Journal of Arid Environments

Much attention has been paid to differences in leaf form and composition among vegetation types, but less to the frequently substantial variation within vegetation types. We focused on the extent to which correlations between variables are the same in both succulent-poor and succulent-rich vegetation in semi-arid SE Spain. Mean foliar [N] of perennials varied among species over a 5-fold range. Across species, [N] was positively correlated with specific leaf area (i.e., leaf area divided by dry mass; SLA) and with water concentration at saturation (WCS) in the grasslands, excluding the one succulent species. In succulent-rich vegetation on marl, SLA was correlated with [N] but not WCS, and there was a wedge-shaped relationship between [N] and WCS. Foliar [N] and [P] were positively correlated in the grasslands, but not in succulent-rich vegetation on marl. The N/P quotient varied from 8 to 29, with mean 14 in grassland on limestone and mean 26 in grassland on deep soil over gypsum. Our chief finding is that most correlations among SLA, WCS, [N] and [P] found in the non-succulent vegetation are not found in the succulent-rich vegetation. The results are discussed in relation to global patterns and the problems of defining succulence. © 2015 Elsevier Ltd. Source

Macias-Sanchez E.,University of Granada | Martinez J.G.,University of Granada | Aviles J.M.,EEZA | Soler M.,University of Granada

The appearance of plumage in brood parasites represents an evolutionary conflict between sexual selection that favours colourful plumages, and parasite-host coevolution that favours crypsis. In this study we quantified the degree of sexual dimorphism from a sample of 179 Great Spotted Cuckoos and determined which features facilitate accurate sex discrimination. In addition, we collected spectrophotometric measures of two colour patches (the crown and the throat) and ran visual models to test for physical and bird-perceivable sexual differences in coloration. We found that males are bigger and brighter than females in both colour patches. Using visual modelling techniques we demonstrate for the first time that adult Great Spotted Cuckoos are sexually dichromatic in an avian visual framework. © 2013 British Ornithologists' Union. Source

Sanchez-Canete E.P.,EEZA | Sanchez-Canete E.P.,Centro Andaluz Of Medio Ambiente | Serrano-Ortiz P.,EEZA | Serrano-Ortiz P.,Centro Andaluz Of Medio Ambiente | And 5 more authors.
Geophysical Research Letters

Recent studies of carbonate ecosystems suggest a possible contribution of subterranean ventilation to the net ecosystem carbon balance. However, both the overall importance of such CO2 exchange processes and their drivers remain unknown. Here we analyze several dry-season episodes of net CO 2 emissions to the atmosphere, along with soil and borehole CO 2 measurements. Results highlight important events where rapid decreases of underground CO2 molar fractions correlate well with sizeable CO2 release to the atmosphere. Such events, with high friction velocities, are attributed to ventilation processes, and should be accounted for by predictive models of surface CO2 exchange. © 2011 by the American Geophysical Union. Source

Sanchez-Tojar A.,University of Granada | Sanchez-Tojar A.,Max Planck Institute for Ornithology (Seewiesen) | Parejo D.,University of Extremadura | Martinez J.G.,University of Granada | And 2 more authors.
Acta Ornithologica

The European Roller Coracias garrulus is a secondary hole-nesting bird that has largely been considered genetically monogamous, although molecular techniques to confirm this assumption had never been used. Here we test this hypothesis by using 5 years of data from a nest-box population in the south of Spain and 6 microsatellite markers recently tested in the species. Overall, 49 broods containing 176 nestlings were included. The average annual percentage of nests with either extra-pair paternity or extra-pair maternity was 4.6 and 6.4, respectively. No evidence of cooperative breeding was found in the provisioning videos analysed. Our work confirms for the first time that European Rollers are not exclusively genetically monogamous, opening new avenues in the study of the breeding biology of this near-threatened species. © 2015, BioOne. All rights reserved. Source

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