Long-term nitrogen deposition linked to reduced water use efficiency in forests with low phosphorus availability

Huang Z., Liu B., Davis M., Sardans J., Peñuelas J., Billings S. (2015) Long-term nitrogen deposition linked to reduced water use efficiency in forests with low phosphorus availability. New Phytologist. : 0-0.
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Doi: 10.1111/nph.13785

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The impact of long-term nitrogen (N) deposition is under-studied in phosphorus (P)-limited subtropical forests. We exploited historically collected herbarium specimens to investigate potential physiological responses of trees in three subtropical forests representing an urban-to-rural gradient, across which N deposition has probably varied over the past six decades. We measured foliar [N] and [P] and stable carbon (δ13C), oxygen (δ18O) and nitrogen (δ15N) isotopic compositions in tissue from herbarium specimens of plant species collected from 1947 to 2014. Foliar [N] and N: P increased, and δ15N and [P] decreased in the two forests close to urban centers. Consistent with recent studies demonstrating that N deposition in the region is 15N-depleted, these data suggest that the increased foliar [N] and N: P, and decreased [P], may be attributable to atmospheric deposition and associated enhancement of P limitation. Estimates of intrinsic water use efficiency calculated from foliar δ13C decreased by c. 30% from the 1950s to 2014, contrasting with multiple studies investigating similar parameters in N-limited forests. This effect may reflect decreased photosynthesis, as suggested by a conceptual model of foliar δ13C and δ18O. Long-term N deposition may exacerbate P limitation and mitigate projected increases in carbon stocks driven by elevated CO2 in forests on P-limited soils. © 2015 New Phytologist Trust.

Llegeix més

Background fish feminization effects in European remote sites

Jarque S., Quiros L., Grimalt J.O., Gallego E., Catalan J., Lackner R., Pina B. (2015) Background fish feminization effects in European remote sites. Scientific Reports. 5: 0-0.
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Doi: 10.1038/srep11292

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Human activity has spread trace amounts of chemically stable endocrine-disrupting pollutants throughout the biosphere. These compounds have generated a background level of estrogenic activity that needs to be assessed. Fish are adequate sentinels for feminization effects as male specimens are more sensitive than humans to exogenous estrogenic compounds. High mountain lakes, the most distant environments of continental areas, only receive semi-volatile compounds from atmospheric deposition. We analyzed the expression levels of estrogen-regulated genes in male fish from these mountain lakes in Europe. Incipient feminization involving expression of estrogen receptor and zona radiata genes revealed a widespread diffuse estrogenic impact. This effect was correlated with the concentrations of some organochlorine compounds in fish and was consistent with the persistent occurrence of these tropospheric pollutants in the most remote planet regions. These results should be of general concern given the increasing endocrine disruption effects in human populations. © 2015, Nature Publishing Group. All rights reserved.

Llegeix més

Social evolution. Genomic signatures of evolutionary transitions from solitary to group living

Kapheim K.M., Pan H., Li C., Salzberg S.L., Puiu D., Magoc T., Robertson H.M., Hudson M.E., Venkat A., Fischman B.J., Hernandez A., Yandell M., Ence D., Holt C., Yocum G.D., Kemp W.P., Bosch J., Waterhouse R.M., Zdobnov E.M., Stolle E., Kraus F.B., Helbing S., Moritz R.F., Glastad K.M., Hunt B.G., Goodisman M.A., Hauser F., Grimmelikhuijzen C.J., Pinheiro D.G., Nunes F.M., Soares M.P., Tanaka ED., Simoes Z.L., Hartfelder K., Evans J.D., Barribeau S.M., Johnson R.M., Massey J.H., Southey B.R., Hasselmann M., Hamacher D., Biewer M., Kent C.F., Zayed A., Blatti C., Sinha S., Johnston J.S., Hanrahan S.J., Kocher S.D., Wang J., Robinson G.E., Zhang G. (2015) Social evolution. Genomic signatures of evolutionary transitions from solitary to group living. Science (New York, N.Y.). 348: 1139-1143.
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Doi: 10.1126/science.aaa4788

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The evolution of eusociality is one of the major transitions in evolution, but the underlying genomic changes are unknown. We compared the genomes of 10 bee species that vary in social complexity, representing multiple independent transitions in social evolution, and report three major findings. First, many important genes show evidence of neutral evolution as a consequence of relaxed selection with increasing social complexity. Second, there is no single road map to eusociality; independent evolutionary transitions in sociality have independent genetic underpinnings. Third, though clearly independent in detail, these transitions do have similar general features, including an increase in constrained protein evolution accompanied by increases in the potential for gene regulation and decreases in diversity and abundance of transposable elements. Eusociality may arise through different mechanisms each time, but would likely always involve an increase in the complexity of gene networks. Copyright © 2015, American Association for the Advancement of Science.

Llegeix més

Direct and indirect impacts of climate and socio-economic change in Europe: a sensitivity analysis for key land- and water-based sectors

Kebede A.S., Dunford R., Mokrech M., Audsley E., Harrison P.A., Holman I.P., Nicholls R.J., Rickebusch S., Rounsevell M.D.A., Sabate S., Sallaba F., Sanchez A., Savin C., Trnka M., Wimmer F. (2015) Direct and indirect impacts of climate and socio-economic change in Europe: a sensitivity analysis for key land- and water-based sectors. Climatic Change. 128: 261-277.
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Doi: 10.1007/s10584-014-1313-y

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Integrated cross-sectoral impact assessments facilitate a comprehensive understanding of interdependencies and potential synergies, conflicts, and trade-offs between sectors under changing conditions. This paper presents a sensitivity analysis of a European integrated assessment model, the CLIMSAVE integrated assessment platform (IAP). The IAP incorporates important cross-sectoral linkages between six key European land- and water-based sectors: agriculture, biodiversity, flooding, forests, urban, and water. Using the IAP, we investigate the direct and indirect implications of a wide range of climatic and socio-economic drivers to identify: (1) those sectors and regions most sensitive to future changes, (2) the mechanisms and directions of sensitivity (direct/indirect and positive/negative), (3) the form and magnitudes of sensitivity (linear/non-linear and strong/weak/insignificant), and (4) the relative importance of the key drivers across sectors and regions. The results are complex. Most sectors are either directly or indirectly sensitive to a large number of drivers (more than 18 out of 24 drivers considered). Over twelve of these drivers have indirect impacts on biodiversity, forests, land use diversity, and water, while only four drivers have indirect effects on flooding. In contrast, for the urban sector all the drivers are direct. Moreover, most of the driver–indicator relationships are non-linear, and hence there is the potential for ‘surprises’. This highlights the importance of considering cross-sectoral interactions in future impact assessments. Such systematic analysis provides improved information for decision-makers to formulate appropriate adaptation policies to maximise benefits and minimise unintended consequences. © 2015, Springer Science+Business Media Dordrecht.

Llegeix més

Linking OMI HCHO and MODIS PRI satellite data with BVOCS emissions in NE Spain

Kefauver S.C., Filella I., Zhang C., Penuelas J. (2015) Linking OMI HCHO and MODIS PRI satellite data with BVOCS emissions in NE Spain. International Geoscience and Remote Sensing Symposium (IGARSS). 2015-November: 2661-2664.
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Doi: 10.1109/IGARSS.2015.7326360

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Volatile organic compounds (VOCs) play several important roles on tropospheric chemical composition. Biogenic VOCs (BVOCs) are the largest source of NMVOCs (non-methane VOCs), accounting for the release of up to 10% of total C fixed by plants in photosynthesis. As isoprene is often the dominant source of atmospheric formaldehyde (HCHO) detected using satellite sensors, it is often correlated directly to satellite HCHO observations without accounting for other HCHO sources. Here we investigate the importance of quantifying monoterpene emissions when linking remotely sensed HCHO vertical columns to terrestrial BVOCs emissions at four different ecosystems in NE Spain where monoterpene-isoprene emissions ratios are known to be unusually high. Average HCHO yield for present monoterpenes was approximately 29% compared to 45% for isoprene. Including monoterpene HCHO yield contributions in total atmospheric HCHO concentrations improved correlations from R2 of 0.35 to 0.66 and R2 of 0.56 to 0.89 when comparing OMI HCHO and MODIS PRI satellite with HCHO field measurements, respectively. © 2015 IEEE.

Llegeix més

Experimental evidence for inherent lévy search behaviour in foraging animals

Kolzsch A., Alzate A., Bartumeus F., De Jager M., Weerman E.J., Hengeveld G.M., Naguib M., Nolet B.A., Van De Koppel J. (2015) Experimental evidence for inherent lévy search behaviour in foraging animals. Proceedings of the Royal Society B: Biological Sciences. 282: 0-0.
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Doi: 10.1098/rspb.2015.0424

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Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. © 2015 The Author(s) Published by the Royal Society.

Llegeix més

Variations in functional diversity in snowbed plant communities determining snowbed continuity

Komac B., Pladevall C., Penuelas J., Conesa J.V., Domenech M. (2015) Variations in functional diversity in snowbed plant communities determining snowbed continuity. Plant Ecology. : 0-0.
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Doi: 10.1007/s11258-015-0506-4

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Snowbed habitats are home to plant species that have adapted to particular environmental conditions (i.e. long-lasting snow cover and short growing seasons). The presence of most of these species is dependent on a long period of snow cover and so their conservation may well depend in the future on their ability to adapt to the effects of climate change. The aim of this study was to assess the persistence of snowbed communities using functional trait and functional diversity indices. We used data for plant species abundances from 32 snowbeds in Andorra (Pyrenees) classified according to certain environmental variables (elevation, exposure, soil type and temperature) and snow cover duration. Nine functional traits were used to evaluate the functional diversity, which was characterised as consisting of functional richness, functional evenness, functional dispersion, functional divergence and the community-weighted mean trait values. In two snowbeds, plant traits were also recorded and variation analysed along a snowmelt gradient. We found that snowbed specialist species had functional traits that were well adapted to the particular abiotic conditions of snowbed habitats but that there was a predominance of the functional traits of grass species in species originating in neighbouring communities. We found less functional richness, fewer strategies and lower competitive ability in the adapted species as the severity of the abiotic conditions increased. Snowbed specialist species appear to be less sensitive to the length of the growing season than species from neighbouring communities. Our results suggest that non-specialist species will tend to appear more frequently in those snowbed habitats affected by the reduction in snow cover duration. © 2015 Springer Science+Business Media Dordrecht

Llegeix més

Development of an ISO-standard for the preservation of geospatial data and metadata: ISO 19165

Kresse W., Pau J.M. (2015) Development of an ISO-standard for the preservation of geospatial data and metadata: ISO 19165. Photogrammetrie, Fernerkundung, Geoinformation. 2015: 449-456.
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Doi: 10.1127/pfg/2015/0278

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Most of the paper maps produced a century ago are still very accessible in cartographic libraries preserved by the producer. It is our present obligation to guarantee the preservation of digital geospatial data today and allow for digital cartographic accessibility one century into the future. In addition, there is an increasing demand for older maps that goes beyond pure historical interest motivated by the study of dynamic problems such as impacts of the climate change, human activities and sustainability. The long-term preservation of large volumes of geospatial data in a uniform way still remains an unsolved question. A systematic solution has been demanded by National Mapping and Archival Agencies in Europe and North America. One year ago the ISO/TC 211 "Geographic information /Geomatics" published a New Work Item Proposal (NWIP) named ISO 19165 "Preservation of digital data and metadata" accompanied by a Working Draft document. The proposed standard is built upon the principles laid down in the ISO 14721 "Open Archival Information Systems" and upon thedatamodehofthe ISO 19115-1 "Metadata - Part 1: Fundamentals". This article reports on the specialization of both standards for the purpose of archiving of geospatial data and asks for contributions to the ISO 19165 under development. © 2015 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Llegeix més

Increased sensitivity to climate change in disturbed ecosystems

Kroel-Dulay G., Ransijn J., Schmidt I.K., Beier C., De Angelis P., De Dato G., Dukes J.S., Emmett B., Estiarte M., Garadnai J., Kongstad J., Kovacs-Lang E., Larsen K.S., Liberati D., Ogaya R., Riis-Nielsen T., Smith A.R., Sowerby A., Tietema A., Penuelas J. (2015) Increased sensitivity to climate change in disturbed ecosystems. Nature Communications. 6: 0-0.
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Doi: 10.1038/ncomms7682

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Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports this relationship for the perturbation of climate change. Here we show that vegetation (abundance, species richness and species composition) across seven European shrublands is quite resistant to moderate experimental warming and drought, and responsiveness is associated with the dynamic state of the ecosystem, with recently disturbed sites responding to treatments. Furthermore, most of these responses are not rapid (2-5 years) but emerge over a longer term (7-14 years). These results suggest that successional state influences the sensitivity of ecosystems to climate change, and that ecosystems recovering from disturbances may be sensitive to even modest climatic changes. A research bias towards undisturbed ecosystems might thus lead to an underestimation of the impacts of climate change. © 2015 Macmillan Publishers Limited. All rights reserved.

Llegeix més

Random processes and phylogenetic loss caused by plant invasions

Lapiedra O., Sol D., Traveset A., Vila M. (2015) Random processes and phylogenetic loss caused by plant invasions. Global Ecology and Biogeography. : 0-0.
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Doi: 10.1111/geb.12310

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Aim: Although biological invasions represent a major cause of biodiversity loss, the actual mechanisms driving species extinctions remain insufficiently understood. Here we investigate the role of three processes as drivers of phylogenetic loss in invaded local plant communities, namely the 'biotic resistance', 'environmental filtering' and 'functional equivalence' hypotheses. Location: Balearic Islands (western Mediterranean). Methods: We quantified the phylogenetic diversity and structure of 109 pairs of invaded and non-invaded local plant communities from two Mediterranean islands. Each pair contained one control plot and one plot invaded either by the deciduous tree Ailanthus altissima, the succulent subshrubs Carpobrotus spp. or the pseudoannual geophyte Oxalis pes-caprae. We combined generalized linear models, analyses of phylogenetic community structure and generalized linear mixed models using a Markov chain Monte Carlo technique (MCMCglmm) to contrast the 'biotic resistance', 'environmental filtering' and 'functional equivalence' hypotheses. Results: While the phylogenetic structure of the non-invaded communities was not more clustered or overdispersed than expected by chance, minimum phylogenetic distance to the invasive species increased in invaded assemblages, in which the magnitude of phylogenetic diversity loss ranged from 6 to 37% depending on the invader's identity. Invader or island identity did not explain the probabilities of native species becoming locally extinct. Rather, the likelihood of extinction was mainly explained by species abundance, with scarcer species exhibiting a higher chance of becoming locally extinct. Species identity explained a small fraction of the variation in extinction risk (12%), independently of each species' evolutionary history. Main conclusions: The most relevant driver of local extinction is a stochastic process where less abundant species tend to disappear more frequently irrespective of their evolutionary history. This has strong implications for conservation because it suggests that in the study region the invaders are unlikely to drive regional and global extinctions except in cases where the native species is already rare. © 2015 John Wiley & Sons Ltd.

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