Time filter

Source Type

Rabanales, Spain

This study contributes with the first data on physical and taxonomical structure of macrofaunal assemblages of maërl beds from the Canary Islands. Maërl beds and Cymodocea nodosa meadows of the Canary Islands are considered biodiversity hot-spots in terms of taxonomic and functional biodiversity with a broad geographical and depth ranges. The authors have studied the structure of the macrofaunal assemblages on different habitat types (Cymodocea, Caulerpa, sabellid field, garden eel and maërl beds). Samples were taken at a range of depths between 14 and 46 m. Correlations were performed among abiotic variables (granulometry, organic matter, nitrogen and phosphates) and the most abundant taxa. Similarity analysis was performed to explore the patchiness of seabeds at a local scale. Significant differences were found in macrofaunal assemblages among seabed types, with highest abundances and lowest biodiversity in sabellid fields, where the sabellid Bispira viola dominated. The polychaetes Aponuphis bilineata and Chone filicauda and the mollusc Turritella brochii were the most abundant taxa on maërl beds. The mosaic of granulometric conditions would explain the associated macroinfaunal community structure and contribute to the creation of diversity on these relatively well preserved seabeds at a local scale. © The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg 2012. Source

Gonzalez-Rodriguez V.,Area de Ecologia | Villar R.,Area de Ecologia | Casado R.,Area de Ecologia | Suarez-Bonnet E.,Area de Ecologia | And 2 more authors.
Annals of Forest Science | Year: 2011

Introduction : The great spatial and temporal heterogeneity of Mediterranean ecosystems can influence establishment success in woody species, whose natural regeneration occurs to a very small extent. In this work, the effect of the spatial pattern of environmental variables (light availability, soil moisture and herbaceous production) on seedling emergence, growth, survival and establishment success was examined by using a spatially explicit approach. Methods : Seeds of four Quercus species differing in leaf longevity (Quercus ilex, Quercus suber, Quercus faginea and Quercus pyrenaica) were sown in two plots located in a holm oak forest (southern Spain). The spatial pattern of the studied variables was examined by Spatial Analysis by Distance Indices. Results : All environmental variables exhibited an aggregated spatial pattern. There was no clear spatial association between the environmental variables and emergence and survival. Only soil moisture during the dry season was spatially associated with the establishment success of all the species. Species also differed in survival and establishment success, with evergreens having higher percentages than deciduous. No aggregated spatial pattern for growth and morphological traits was apparent, these being more dependent on seed mass than on environmental factors. Identifying which microsites facilitate regeneration may provide useful hints with a view in focusing restoration endeavours on microenvironments with high survival percentage. © 2011 INRA and Springer Science+Business Media B.V. Source

The distribution of the Monarch butterfly Danaus plexippus (L.) has been studied in an area close to the Strait of Gibraltar (southern Spain). The butterfly presents a fragmented distribution related to that of the Asclepidaceae Gomphocarpus fruticosus and Asclepias curassavica, which are the food-plants of their larvae and the main nectar source of the butterflies. Sixty-three patches with different combinations and abundance of one or both species have been located. During 2008 the Monarch butterfly was located in 36 of those patches, in variable numbers, up to 100 individuals flying simultaneously. Within these high-density patches, larvae not only completely defoliated the annual investment of plants, but also consumed flowers, fruits and apical stems. As a consequence, butterflies dispersed to other more favourable fragments. The appearance of this species in different localities of the Iberian Peninsula should be related to a metapopulation dynamic with dispersing individuals moving between patches. Sporadic arrival of individuals coming from other continents can not be excluded. Source

Alburquerque J.A.,Area de Ecologia | Salazar P.,Area de Ecologia | Barron V.,University of Cordoba, Spain | Torrent J.,University of Cordoba, Spain | And 3 more authors.
Agronomy for Sustainable Development | Year: 2013

Climate change and global warming have worldwide adverse consequences. Biochar production and its use in agriculture can play a key role in climate change mitigation and help improve the quality and management of waste materials coming from agriculture and forestry. Biochar is a carbonaceous material obtained from thermal decomposition of residual biomass at relatively low temperature and under oxygen limited conditions (pyrolysis). Biochar is currently a subject of active research worldwide because it can constitute a viable option for sustainable agriculture due to its potential as a long-term sink for carbon in soil and benefits for crops. However, to date, the results of research studies on biochar effects on crop production show great variability, depending on the biochar type and experimental conditions. Therefore, it is important to identify the beneficial aspects of biochar addition to soil on crop yield in order to promote the adoption of this practice in agriculture. In this study, the effects of two types of biochar from agricultural wastes typical of Southern Spain: wheat straw and olive tree pruning, combined with different mineral fertilization levels on the growth and yield of wheat (Triticum durum L. cv. Vitron) were evaluated. Durum wheat was pot-grown for 2 months in a growth chamber on a soil collected from an agricultural field near Córdoba, Southern Spain. Soil properties and plant growth variables were studied in order to assess the agronomic efficiency of biochar. Our results show that biochar addition to a nutrient-poor, slightly acidic loamy sand soil had little effect on wheat yield in the absence of mineral fertilization. However, at the highest mineral fertilizer rate, addition of biochar led to about 20-30 % increase in grain yield compared with the use of the mineral fertilizer alone. Both biochars acted as a source of available P, which led to beneficial effects on crop production. In contrast, the addition of biochar resulted in decreases in available N and Mn. A maximum reduction in plant nutrient concentration of 25 and 80 % compared to nonbiochar-treated soils for N and Mn, respectively, was detected. This fact was related to the own nature of biochar: low available nitrogen content, high adsorption capacity, and low mineralization rate for N; and alkaline pH and high carbonate content for Mn. Our results indicate that biochar-based soil management strategies can enhance wheat production with the environmental benefits of global warming mitigation. This can contribute positively to the viability and benefits of agricultural production systems. However, the nutrient-biochar interactions should receive special attention due to the great variability in the properties of biochar-type materials. © 2013 INRA and Springer-Verlag France. Source

Viana I.G.,Area de Ecologia | Aboal J.R.,Area de Ecologia | Fernandez J.A.,Area de Ecologia | Real C.,University of Santiago de Compostela | And 2 more authors.
Water Research | Year: 2010

Different European Framework Directives have established a series of objectives for conservation of the coast, and monitoring tools must be made available to test compliance with these aims. In the present study the use of macroalgae deposited in an Environmental Specimen Bank was evaluated as a possible environmental tool for monitoring the coastal ecosystem. The concentrations of Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn in three species of the genus Fucus (Fucus spiralis, Fucus vesiculosus and Fucus ceranoides) were measured at sampling sites distributed along the coast of Galicia (NW Spain). In the period 1990-2001, the concentrations of the metals were higher in 1990 than in 2001, with the exception of: i) Mn in F. ceranoides and Fe in F. spiralis-F. vesiculosus, for which there were no differences between the sampling periods, and ii) Zn in F. vesiculosus and Fe in F. ceranoides, for which the concentrations were higher in 2001 than in 1990. In the period 2001-2007 concentrations of the metals were more stable, especially in F. ceranoides (e.g. Al, Fe, Hg, Ni and V). The concentrations were also more stable vin F. vesiculosus in 2005 (i.e. Al, Cr, Fe, Mn and Zn). The population density distributions are consistent with the results of the statistical tests. The results indicate that macroalgae of the genus Fucus may be useful for applying different European Framework Directives, given that the macroalgae are sufficiently sensitive to changes in concentrations of metals, and may be suitable for long-term monitoring and used for the detection of increased concentrations of metals (real-time monitoring). © 2009 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations