Looking for variable molecular markers in the chestnut gall wasp Dryocosmus kuriphilus: First comparison across genes

Bonal R., Vargas-Osuna E., Mena J.D., Aparicio J.M., Santoro M., Martín A. (2018) Looking for variable molecular markers in the chestnut gall wasp Dryocosmus kuriphilus: First comparison across genes. Scientific Reports. 8: 0-0.
Link
Doi: 10.1038/s41598-018-23754-z

Abstract:

The quick spread of the chestnut gall wasp Dryocosmus kuriphilus in Europe constitutes an outstanding example of recent human-aided biological invasion with dramatic economic losses. We screened for the first time a set of five nuclear and mitochondrial genes from D. kuriphilus collected in the Iberian Peninsula, and compared the sequences with those available from the native and invasive range of the species. We found no genetic variability in Iberia in none of the five genes, moreover, the three genes compared with other European samples showed no variability either. We recorded four cytochrome b haplotypes in Europe; one was genuine mitochondrial DNA and the rest nuclear copies of mitDNA (numts), what stresses the need of careful in silico analyses. The numts formed a separate cluster in the gene tree and at least two of them might be orthologous, what suggests that the invasion might have started with more than one individual. Our results point at a low initial population size in Europe followed by a quick population growth. Future studies assessing the expansion of this pest should include a large number of sampling sites and use powerful nuclear markers (e. g. Single Nucleotide Polymorphisms) to detect genetic variability. © 2018 The Author(s).

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Satellite passive microwaves reveal recent climate-induced carbon losses in African drylands

Brandt M., Wigneron J.-P., Chave J., Tagesson T., Penuelas J., Ciais P., Rasmussen K., Tian F., Mbow C., Al-Yaari A., Rodriguez-Fernandez N., Schurgers G., Zhang W., Chang J., Kerr Y., Verger A., Tucker C., Mialon A., Rasmussen L.V., Fan L., Fensholt R. (2018) Satellite passive microwaves reveal recent climate-induced carbon losses in African drylands. Nature Ecology and Evolution. : 1-9.
Link
Doi: 10.1038/s41559-018-0530-6

Abstract:

The African continent is facing one of the driest periods in the past three decades as well as continued deforestation. These disturbances threaten vegetation carbon (C) stocks and highlight the need for improved capabilities of monitoring large-scale aboveground carbon stock dynamics. Here we use a satellite dataset based on vegetation optical depth derived from low-frequency passive microwaves (L-VOD) to quantify annual aboveground biomass-carbon changes in sub-Saharan Africa between 2010 and 2016. L-VOD is shown not to saturate over densely vegetated areas. The overall net change in drylands (53% of the land area) was −0.05 petagrams of C per year (Pg C yr−1) associated with drying trends, and a net change of −0.02 Pg C yr−1 was observed in humid areas. These trends reflect a high inter-annual variability with a very dry year in 2015 (net change, −0.69 Pg C) with about half of the gross losses occurring in drylands. This study demonstrates, first, the applicability of L-VOD to monitor the dynamics of carbon loss and gain due to weather variations, and second, the importance of the highly dynamic and vulnerable carbon pool of dryland savannahs for the global carbon balance, despite the relatively low carbon stock per unit area. © 2018 The Author(s)

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Thinning increases tree growth by delaying drought-induced growth cessation in a Mediterranean evergreen oak coppice

Cabon, A., Mouillot, F., Lempereur, M., Ourcival, J.-M., Simioni, G., Limousin, J.-M. (2018) Thinning increases tree growth by delaying drought-induced growth cessation in a Mediterranean evergreen oak coppice. Forest Ecology and Management. 409: 333-342.
Link
Doi: 10.1016/j.foreco.2017.11.030

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ORCHIDEE-SOM: Modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

Camino-Serrano M., Guenet B., Luyssaert S., Ciais P., Bastrikov V., De Vos B., Gielen B., Gleixner G., Jornet-Puig A., Kaiser K., Kothawala D., Lauerwald R., Peñuelas J., Schrumpf M., Vicca S., Vuichard N., Walmsley D., Janssens I.A. (2018) ORCHIDEE-SOM: Modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe. Geoscientific Model Development. 11: 937-957.
Link
Doi: 10.5194/gmd-11-937-2018

Abstract:

Current land surface models (LSMs) typically represent soils in a very simplistic way, assuming soil organic carbon (SOC) as a bulk, and thus impeding a correct representation of deep soil carbon dynamics. Moreover, LSMs generally neglect the production and export of dissolved organic carbon (DOC) from soils to rivers, leading to overestimations of the potential carbon sequestration on land. This common oversimplified processing of SOC in LSMs is partly responsible for the large uncertainty in the predictions of the soil carbon response to climate change. In this study, we present a new soil carbon module called ORCHIDEE-SOM, embedded within the land surface model ORCHIDEE, which is able to reproduce the DOC and SOC dynamics in a vertically discretized soil to 2gm. The model includes processes of biological production and consumption of SOC and DOC, DOC adsorption on and desorption from soil minerals, diffusion of SOC and DOC, and DOC transport with water through and out of the soils to rivers. We evaluated ORCHIDEE-SOM against observations of DOC concentrations and SOC stocks from four European sites with different vegetation covers: A coniferous forest, a deciduous forest, a grassland, and a cropland. The model was able to reproduce the SOC stocks along their vertical profiles at the four sites and the DOC concentrations within the range of measurements, with the exception of the DOC concentrations in the upper soil horizon at the coniferous forest. However, the model was not able to fully capture the temporal dynamics of DOC concentrations. Further model improvements should focus on a plant- A nd depth-dependent parameterization of the new input model parameters, such as the turnover times of DOC and the microbial carbon use efficiency. We suggest that this new soil module, when parameterized for global simulations, will improve the representation of the global carbon cycle in LSMs, thus helping to constrain the predictions of the future SOC response to global warming. © Author(s) 2018.

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Knowledge gaps about mixed forests: What do European forest managers want to know and what answers can science provide?

Coll, L., Ameztegui, A., Collet, C., Löf, M., Mason, B., Pach, M., Verheyen, K., Abrudan, I., Barbati, A., Barreiro, S., Bielak, K., Bravo-Oviedo, A., Ferrari, B., Govedar, Z., Kulhavy, J., Lazdina, D., Metslaid, M., Mohren, F., Pereira, M., Peric, S., Rasztovits, E., Short, I., Spathelf, P., Sterba, H., Stojanovic, D., Valsta, L., Zlatanov, T., Ponette, Q. (2018) Knowledge gaps about mixed forests: What do European forest managers want to know and what answers can science provide?. Forest Ecology and Management. 407: 106-115.
Link
Doi: 10.1016/j.foreco.2017.10.055

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Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental-scale experiment

Connolly, J., Sebastià, M.-T., Kirwan, L., Finn, J.A., Llurba, R., Suter, M., Collins, R.P., Porqueddu, C., Helgadóttir, Á., Baadshaug, O.H., Bélanger, G., Black, A., Brophy, C., Čop, J., Dalmannsdóttir, S., Delgado, I., Elgersma, A., Fothergill, M., Frankow-Lindberg, B.E., Ghesquiere, A., Golinski, P., Grieu, P., Gustavsson, A.-M., Höglind, M., Huguenin-Elie, O., Jørgensen, M., Kadziuliene, Z., Lunnan, T., Nykanen-Kurki, P., Ribas, A., Taube, F., Thumm, U., De Vliegher, A., Lüscher, A. (2018) Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental-scale experiment. Journal of Applied Ecology. 55: 852-862.
Link
Doi: 10.1111/1365-2664.12991

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Spatial Variation of Soil CO2, CH4 and N2O Fluxes Across Topographical Positions in Tropical Forests of the Guiana Shield

Courtois E.A., Stahl C., van Den Berge J., Bréchet L., van Langenhove L., Richter A., Urbina I., Soong J.L., Peñuelas J., Janssens I.A. (2018) Spatial Variation of Soil CO2, CH4 and N2O Fluxes Across Topographical Positions in Tropical Forests of the Guiana Shield. Ecosystems. : 1-14.
Link
Doi: 10.1007/s10021-018-0232-6

Abstract:

The spatial variation of soil greenhouse gas fluxes (GHG; carbon dioxide—CO2, methane—CH4 and nitrous oxide—N2O) remains poorly understood in highly complex ecosystems such as tropical forests. We used 240 individual flux measurements of these three GHGs from different soil types, at three topographical positions and in two extreme hydric conditions in the tropical forests of the Guiana Shield (French Guiana, South America) to (1) test the effect of topographical positions on GHG fluxes and (2) identify the soil characteristics driving flux variation in these nutrient-poor tropical soils. Surprisingly, none of the three GHG flux rates differed with topographical position. CO2 effluxes covaried with soil pH, soil water content (SWC), available nitrogen and total phosphorus. The CH4 fluxes were best explained by variation in SWC, with soils acting as a sink under drier conditions and as a source under wetter conditions. Unexpectedly, our study areas were generally sinks for N2O and N2O fluxes were partly explained by total phosphorus and available nitrogen concentrations. This first study describing the spatial variation of soil fluxes of the three main GHGs measured simultaneously in forests of the Guiana Shield lays the foundation for specific studies of the processes underlying the observed patterns. © 2018 Springer Science+Business Media, LLC, part of Springer Nature

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ELISA for detection of variant rabbit haemorrhagic disease virus RHDV2 antigen in liver extracts

Dalton, K.P., Podadera, A., Granda, V., Nicieza, I., del Llano, D., González, R., de los Toyos, J.R., García Ocaña, M., Vázquez, F., Martín Alonso, J.M., Prieto, J.M., Parra, F., Casais, R. (2018) ELISA for detection of variant rabbit haemorrhagic disease virus RHDV2 antigen in liver extracts. Journal of Virological Methods. 251: 38-42.
Link
Doi: 10.1016/j.jviromet.2017.09.019

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Synoptic weather conditions and changing fire regimes in a Mediterranean environment

Duane, A., Brotons, L. (2018) Synoptic weather conditions and changing fire regimes in a Mediterranean environment. Agricultural and Forest Meteorology. 253-254: 190-202.
Link
Doi: 10.1016/j.agrformet.2018.02.014

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A MODIS photochemical reflectance index (PRI) as an estimator of isoprene emissions in a temperate deciduous forest

Filella I., Zhang C., Seco R., Potosnak M., Guenther A., Karl T., Gamon J., Pallardy S., Gu L., Kim S., Balzarolo M., Fernandez-Martinez M., Penuelas J. (2018) A MODIS photochemical reflectance index (PRI) as an estimator of isoprene emissions in a temperate deciduous forest. Remote Sensing. 10: 0-0.
Link
Doi: 10.3390/rs10040557

Abstract:

The quantification of isoprene and monoterpene emissions at the ecosystem level with available models and field measurements is not entirely satisfactory. Remote-sensing techniques can extend the spatial and temporal assessment of isoprenoid fluxes. Detecting the exchange of biogenic volatile organic compounds (BVOCs) using these techniques is, however, a very challenging goal. Recent evidence suggests that a simple remotely sensed index, the photochemical reflectance index (PRI), which is indicative of light-use efficiency, relative pigment levels and excess reducing power, is a good indirect estimator of foliar isoprenoid emissions. We tested the ability of PRI to assess isoprenoid fluxes in a temperate deciduous forest in central USA throughout the entire growing season and under moderate and extreme drought conditions. We compared PRI time series calculated with MODIS bands to isoprene emissions measured with eddy covariance. MODIS PRI was correlated with isoprene emissions for most of the season, until emissions peaked. MODIS PRI was also able to detect the timing of the annual peak of emissions, even when it was advanced in response to drought conditions. PRI is thus a promising index to estimate isoprene emissions when it is complemented by information on potential emission. It may also be used to further improve models of isoprene emission under drought and other stress conditions. Direct estimation of isoprene emission by PRI is, however, limited, because PRI estimates LUE, and the relationship between LUE and isoprene emissions can be modified by severe stress conditions. © 2018 by the authors.

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