Multivariate effect gradients driving forest demographic responses in the Iberian Peninsula

Coll M., Penuelas J., Ninyerola M., Pons X., Carnicer J. (2013) Multivariate effect gradients driving forest demographic responses in the Iberian Peninsula. Forest Ecology and Management. 303: 195-209.
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Doi: 10.1016/j.foreco.2013.04.010

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A precise knowledge of forest demographic gradients in the Mediterranean area is essential to assess future impacts of climate change and extreme drought events. Here we studied the geographical patterns of forest demography variables (tree recruitment, growth and mortality) of the main species in Spain and assessed their multiple ecological drivers (climate, topography, soil, forest stand attributes and tree-specific traits) as well as the geographical variability of their effects and interactions. Quantile modeling analyses allowed a synthetic description of the gradients of multiple covariates influencing forest demography in this area. These multivariate effect gradients showed significantly stronger interactions at the extremes of the rainfall gradient. Remarkably, in all demographic variables, qualitatively different levels of effects and interactions were observed across tree-size classes. In addition, significant differences in demographic responses and effect gradients were also evident between the dominant genus Quercus and Pinus. Quercus species presented significantly higher percentage of plots colonized by new recruits, whereas in Pinus recruitment limitation was significantly higher. Contrasting positive and negative growth responses to temperature were also observed in Quercus and Pinus, respectively. Overall, our results synthesize forest demographic responses across climatic gradients in Spain, and unveil the interactions between driving factors operating in the drier and wetter edges. © 2013 Elsevier B.V.

Llegeix més

New records for the opisthobranch fauna of the Archipelago of the Azores (north-east Atlantic Ocean)

Cordeiro R., Malaquias M.A.E., Mas G., Figueroa I., Borges J.P., Ávila S.P. (2013) New records for the opisthobranch fauna of the Archipelago of the Azores (north-east Atlantic Ocean). Marine Biodiversity Records. 6: 0-0.
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Doi: 10.1017/S1755267213000110

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The occurrence of the opisthobranchs Diaphana globosa, Hermaeopsis variopicta, Doris bertheloti, Rostanga rubra, Janolus cristatus and Flabellina bulbosa in the Azores is reported for the first time. Our findings expand the known geographical distribution of these species in the north-east Atlantic Ocean and increase the known diversity of opisthobranchs in the archipelago to 150 species. These results provide further support for the well-documented affinity of the Azorean marine biota to the eastern Atlantic and Mediterranean coasts. © Marine Biological Association of the United Kingdom 2013.

Llegeix més

Conserving green and blue water in the WANA region

Daly-Hassen, H., Birot, Y., Gracia, C., Palahi, M. (2013) Conserving green and blue water in the WANA region. Climate Change and Food Security in West Asia and North Africa. : 75-88.
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Doi: 10.1007/978-94-007-6751-5_4

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The combined effects of land-use legacies and novel fire regimes on bird distributions in the Mediterranean

De Caceres M., Brotons L., Aquilue N., Fortin M.-J. (2013) The combined effects of land-use legacies and novel fire regimes on bird distributions in the Mediterranean. Journal of Biogeography. 40: 1535-1547.
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Doi: 10.1111/jbi.12111

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Aim: We investigate first whether fire regimes resulting from the combination of climate change and fire-fighting policy may affect species distributions in Mediterranean landscapes, and second to what extent distributional dynamics may be constrained by the spatial legacy of historical land use. Location: Catalonia (north-eastern Spain). Methods: We modelled the distributional responses of 64 forest and open-habitat bird species to nine fire-regime scenarios, defined by combining different levels of climate change and fire suppression efficiency. A fire-succession model was used to stochastically simulate land-cover changes between 2000 and 2050 under these scenarios. We used species distribution models to predict habitat suitability and occupancy dynamics under either no dispersal or full dispersal assumptions. Results: Under many simulated scenarios, the succession from shrubland to forest dominated over the creation of new low-vegetation areas derived from wildfires. Consequently, open-habitat specialists were the group most affected by losses of suitable habitat. Fire regimes obtained under scenarios including high fire suppression efficiency resulted in a larger number of bird species experiencing reductions in their distribution area. Main conclusions: Anthropogenic factors, such as historical land-use change and fire suppression, can drive regional distribution dynamics in directions opposite to those expected from climatic trends. This raises the question of what drivers and interactions should be given priority in the prediction of biodiversity responses to global change at the regional scale. © 2013 Blackwell Publishing Ltd.

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Dissimilarity measurements and the size structure of ecological communities

De Caceres M., Legendre P., He F. (2013) Dissimilarity measurements and the size structure of ecological communities. Methods in Ecology and Evolution. 4: 1167-1177.
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Doi: 10.1111/2041-210X.12116

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Summary: Measurements of community resemblance in ecology are often based on species composition, and the starting point for calculations is usually a site-by-species data table. However, resemblance measurements may not be sufficiently accurate when communities are described using species composition only. Characteristics such as the size of their constituting organisms are also important to understand community organization. Here, we provide a framework that generalizes conventional resemblance measurements by incorporating the size structure of the compared communities. We first introduce the concept of cumulative abundance profile, which generalizes traditional species abundance values, and describe how to calculate it. We then explain our approach to compare cumulative abundance profiles in community resemblance measurements and use a small simulation study to determine which resemblance coefficients appropriately deal with compositional and structural differences. After that, we present an illustrative example where we study the structural and compositional variation between and within six Douglas-fir forest plots in British Columbia, Canada. According to our investigations, the generalizations we suggest for the percentage difference (alias Bray-Curtis dissimilarity) and the Ružička coefficients are appropriate to measure community resemblance in terms of size structure, species composition or both. Our framework allows community resemblance to be measured in terms of either size structure or species composition, or both. A broad range of applications is expected. In the case of terrestrial plant communities, potential applications include analyses of community dynamics and classification of vegetation. © 2013 British Ecological Society.

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Evolution of production and the efficient location of renewable energies. the case of China

Diaz P., Maso J. (2013) Evolution of production and the efficient location of renewable energies. the case of China. Energy Procedia. 40: 15-24.
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Doi: 10.1016/j.egypro.2013.08.003

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The twenty-first century has been a scenario for explosive investment in renewables. This paper examines such investment as well as the policies that support it. China represents a unique case in this regard due to its fast development. Whereas the issue of securing energy supply is becoming increasingly important over time, the energy return ratios, such as EROI, are important to evaluate the efficiency of energy production. A novel methodology is presented to identify the most convenient location to increase efficiency and energy return for renewables. The methodology also assesses the effects of renewables policies at different scales. © 2013 The Authors. Published by Elsevier Ltd.

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Soil carbon stocks and their variability across the forests, shrublands and grasslands of peninsular Spain

Doblas-Miranda E., Rovira P., Brotons L., Martinez-Vilalta J., Retana J., Pla M., Vayreda J. (2013) Soil carbon stocks and their variability across the forests, shrublands and grasslands of peninsular Spain. Biogeosciences. 10: 8353-8361.
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Doi: 10.5194/bg-10-8353-2013

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Accurate estimates of C stocks and fluxes of soil organic carbon (SOC) are needed to assess the impact of climate and land use change on soil C uptake and soil C emissions to the atmosphere. Here, we present an assessment of SOC stocks in forests, shrublands and grasslands of peninsular Spain based on field measurements in more than 900 soil profiles. SOC to a depth of 1 m was modelled as a function of vegetation cover, mean annual temperature, total annual precipitation, elevation and the interaction between temperature and elevation, while latitude and longitude were used to model the correlation structure of the errors. The resulting statistical model was used to estimate SOC in the ∼8 million pixels of the Spanish Forest Map (29.3 × 106 ha). We present what we believe is the most reliable estimation of current SOC in forests, shrublands and grasslands of peninsular Spain thus far, based on the use of spatial modelling, the high number of profiles and the validity and refinement of the data layers employed. Mean concentration of SOC was 8.7 kg m-2, ranging from 2.3 kg m-2 in dry Mediterranean areas to 20.4 kg m -2 in wetter northern locations. This value corresponds to a total stock of 2.544 Tg SOC, which is four times the amount of C estimated to be stored in the biomass of Spanish forests. Climate and vegetation cover were the main variables influencing SOC, with important ecological implications for peninsular Spanish ecosystems in the face of global change. The fact that SOC was positively related to annual precipitation and negatively related to mean annual temperature suggests that future climate change predictions of increased temperature and reduced precipitation may strongly reduce the potential of Spanish soils as C sinks. However, this may be mediated by changes in vegetation cover (e.g. by favouring the development of forests associated to higher SOC values) and exacerbated by perturbations such as fire. The estimations presented here provide a baseline to estimate future changes in soil C stocks and to assess their vulnerability to key global change drivers, and should inform future actions aimed at the conservation and management of C stocks. © 2013 Author(s).

Llegeix més

On the dimensionality of ecological stability

Donohue I., Petchey O.L., Montoya J.M., Jackson A.L., Mcnally L., Viana M., Healy K., Lurgi M., O'Connor N.E., Emmerson M.C. (2013) On the dimensionality of ecological stability. Ecology Letters. 16: 421-429.
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Doi: 10.1111/ele.12086

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Ecological stability is touted as a complex and multifaceted concept, including components such as variability, resistance, resilience, persistence and robustness. Even though a complete appreciation of the effects of perturbations on ecosystems requires the simultaneous measurement of these multiple components of stability, most ecological research has focused on one or a few of those components analysed in isolation. Here, we present a new view of ecological stability that recognises explicitly the non-independence of components of stability. This provides an approach for simplifying the concept of stability. We illustrate the concept and approach using results from a field experiment, and show that the effective dimensionality of ecological stability is considerably lower than if the various components of stability were unrelated. However, strong perturbations can modify, and even decouple, relationships among individual components of stability. Thus, perturbations not only increase the dimensionality of stability but they can also alter the relationships among components of stability in different ways. Studies that focus on single forms of stability in isolation therefore risk underestimating significantly the potential of perturbations to destabilise ecosystems. In contrast, application of the multidimensional stability framework that we propose gives a far richer understanding of how communities respond to perturbations. © 2013 Blackwell Publishing Ltd/CNRS.

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Social networks and internet communities in the field of geographic information and their role in open data government initiatives

Díaz P., Masó J. (2013) Social networks and internet communities in the field of geographic information and their role in open data government initiatives. Frameworks of IT Prosumption for Business Development. : 284-314.
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Doi: 10.4018/978-1-4666-4313-0.ch018

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Users are playing an increasingly relevant role in geospatial data production. The traditional procedure for creating cartography, mainly by experts in official mapping agencies, has evolved into a more participative process for generating data: neogeography. Technology and the Internet are now user-friendly for a wide range of people who have become active users of global networks, such as GEOSS, INSPIRE, Eye On Earth, and EarthCube, and official producers need to adapt to the new era of openness, collaboration, and hybrid maps by adopting open standards. Although the creation of geospatial information is notably growing worldwide, and is enhanced by user-generated content, we may wonder whether this is a feasible alternative to official cartography. This chapter reviews the main geospatial networks based on both bottom-up and top-down data creation approaches, as well as the potentialities and limitations of user-generated content in the scientific field and in decision-making organisms. © 2014 by IGI Global. All rights reserved.

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The dimensionality of ecological networks

Eklof A., Jacob U., Kopp J., Bosch J., Castro-Urgal R., Chacoff N.P., Dalsgaard B., de Sassi C., Galetti M., Guimaraes P.R., Lomascolo S.B., Martin Gonzalez A.M., Pizo M.A., Rader R., Rodrigo A., Tylianakis J.M., Vazquez D.P., Allesina S. (2013) The dimensionality of ecological networks. Ecology Letters. 16: 577-583.
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Doi: 10.1111/ele.12081

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How many dimensions (trait-axes) are required to predict whether two species interact? This unanswered question originated with the idea of ecological niches, and yet bears relevance today for understanding what determines network structure. Here, we analyse a set of 200 ecological networks, including food webs, antagonistic and mutualistic networks, and find that the number of dimensions needed to completely explain all interactions is small (

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