Suchergebnisse

Ulf Büntgen.[et.al.] ; The Périgord black truffle is an exclusive culinary delicacy, but its Mediterranean harvests have declined, despite cultivation efforts since the 1970s. The role of long-term irrigation, symbiotic fungus-host interaction, and microbial belowground progression remain poorly understood, because generally too short experimental settings miss the necessary degree of real world complexity and reliable information from truffle orchards is limited. Here, we conduct the first dendrochronological and wood anatomical assessment of 295 holm oaks, which have been growing under different irrigation intensities in the world's largest truffle orchard in Spain. The relationships between different climatic variables (monthly temperature means and precipitation totals) and dendro-parameters (ring width, vessel count and vessel size) of the oak hosts are utilized to disentangle direct and indirect drivers of truffle fruit body production. Irrigation at medium - instead of high - intensity is most beneficial for oak growth. Non-irrigated trees reveal overall lower stem increments. Warmer temperatures from February to April and wetter conditions from May to July enhance host vitality and possibly also its interplay with fungi symbionts via increased fine root production and mycorrhizal colonization. Adequately irrigated Mediterranean orchards may counteract some of the drought-induced natural truffle decline, and help stabilizing rural tourism, regional agriculture and global markets. © 2014 Elsevier B.V. ; Supported by the WSL-internal DITREC project, the Ernst Göhner Foundation, the ClimFun project of the Norwegian RC (No. 225043), the project AGL2012-40035-C03 (Government of Spain), the project Micosylva+ (Interreg IVB SUDOE SOE3/P2/E533), the Government of Castilla y León, ARAID, the project Xilva (CGL2011-26654, Economy and Competitiveness Ministry), as well as the Operational Program of Education for Competitiveness of Ministry of Education, Youth and Sports of the Czech Republic (No. CZ.1.07/2.3.00/20.0248). We are particularly thankful to the Arotz Food Company for helping us to develop this research (via José Cuenca). José Miguel Altelarrea and to José Antonio Vega Borjabad (Cesefor Foundation) contributed to the fieldwork. ; Peer Reviewed

Outbreak insects are among the major biotic disturbances affecting Mediterranean forests by reducing their growth and vitality through severe defoliations. Despite their relevance for the management of these drought-prone areas, we lack information on the relationships between growth, canopy cover and insect defoliations at ample spatial and temporal scales. Here, we combine remote sensing (vegetation indexes) and dendrochronological information (basal area increment, BAI) to assess the effects of pine processionary moth (Thaumetopoea pityocampa, PPM) defoliations on growth and cover changes of several pine species, mainly focusing on Pinus nigra. We compared both datasets with a long-term field survey of PPM stand defoliations carried out in eastern Spain during the period 1970-2012. Lastly, we fitted linear-mixed models of BAI using as predictors climatic variables and a multi-scalar drought index to distinguish drought-related growth reductions from those attributed to PPM outbreaks. PPM severe defoliations mainly affected edge or low-density stands. Several vegetation indices (Moisture Stress Index, Normalized Burn Ratio and Normalized Difference Infrared Index) reflected the cover decrease corresponding to severe PPM defoliations. We found that trees affected by various severe PPM defoliations took at least 2. years to recover BAI values similar to those observed before the outbreak. The combined use of remote sensing and dendrochronology allows monitoring the impact of PPM defoliations from stands to trees, and these are valuable approaches to forecast outbreaks and their effects on Mediterranean forest. We consider both powerful tools to further assess the interacting effects of climate warming and PPM dynamics on drought-prone forests. © 2014 Elsevier B.V. ; This study was supported by projects PROCLIM and CGL2011-26654 financed by La Caixa-Aragón Government and the Spanish Commission of Science and Technology-FEDER, respectively. JJC acknowledges support by ARAID. We sincerely thank J. D. Galván, A.Q. Alla and the personal from the Forest Health Laboratory (Mora de Rubielos, Gobierno de Aragón) for the help in the field works. The authors acknowledge the Landsat scenes provided by the European Space Agency (ESA) in the context of the project C1P.15257. ; Peer Reviewed

Human beings have used fire as an ecosystem management tool for thousands of years. In the context of the scientific and policy debate surrounding potential climate change adaptation and mitigation strategies, the importance of the impact of relatively recent state fire-exclusion policies on fire regimes has been debated. To provide empirical evidence to this ongoing debate we examine the impacts of state fire-exclusion policies in the chestnut forest ecosystems of two geographically neighbouring municipalities in central Spain, Casillas and Rozas de Puerto Real. Extending the concept of 'Traditional Ecological Knowledge' to include the use of fire as a management tool as 'Traditional Fire Knowledge' (TFK), we take a mixed-methods and interdisciplinary approach to argue that currently observed differences between the municipalities are useful for considering the characteristics of >pre-industrial anthropogenic fire regimes> and their impact on chestnut forest ecosystems. We do this by examining how responses from interviews and questionnaire surveys of local inhabitants about TFK in the past and present correspond to the current biophysical landscape state and recent fire activity (based on data from dendrochronological analysis, aerial photography and official fire statistics). We then discuss the broader implications of TFK decline for future fire management policies across Europe particularly in light of the published results of the EU sponsored Fire Paradox research project. In locations where TFK-based >pre-industrial anthropogenic fire regimes> still exist, ecosystem management strategies for adaptation and mitigation to climate change could be conceivably implemented at a minimal economic and political cost to the state by local communities that have both the TFK and the adequate social, economic and cultural incentives to use it. © 2015 Elsevier Ltd. ; This research was made possible by an Academic Outreach Engagement Grant from Middlebury College. The following Middlebury College and New York University students volunteered as interviewers during the Fall of 2012 and Spring of 2013 semesters: Kimberly Sable, Kaelin Stone, Charlotte O'Herron, Forrest Carroll, Zuzana Vuova, Peter Elbaum, Jillian Mock, Jessica Davis, Cody Beaudreau, Aidan McGrath, Gabrielle Fromer, Fran Bullard, William Marrs, Rosie Mazzarella, Emily Duh, Shaun Devlin, Martin Kim, Samuel Schwartzbad, Priyanka Jhaveri, Renee Antoine, Phillip Origlio, Michael Cutrone, Louis Bedford, Lindsey Skolnik, Nino Kakauridze, Giovanni Barcenes, Ann Yang and Rachel Rinehart. Francisco Seijo would like to thank the Fundación "Equo" for its help in finding local volunteers for the project and the municipal governments of Rozas de Puerto Real and Casillas – and particularly David Saugar and Daniel Moreno – for their kind and disinterested collaboration in the deployment of the survey questionnaire. FS would also like to express his gratitude to Beatriz Pérez Ramos from the Universidad de Castilla-La Mancha and Peter Fule of Northern Arizona University for their helpful comments and contributions to this paper and to Captain Jorge Garcia Rodriguez of the Spanish army for allowing us access to military aerial photographs. Jorge Lozano is being supported by a Prometeo Fellowship from the SENESCYT, a national agency for Education and Science of the Government of Ecuador. James Millington would like to acknowledge the Leverhulme Trust for his Early Career Fellowship (ECF/2010/0378) which funded his fieldwork in the study area. G. Sangüesa-Barreda and J.J. Camarero contributions to this study were supported by projects CGL2011-26654 (Spanish Ministry of Economy and Competitiveness) and 1032S/2013 (OAPN, Spanish Ministry of Agriculture and Environment). All authors would also like to express their gratitude to the people of Rozas and Casillas for their hospitality and, especially, patience in responding to our questions. ; Peer Reviewed

This study links tree-ring growth and gross primary production for a variety of forest types under different environmental conditions across Spain. NOAA-AVHRR satellite imagery data were combined with dendrochronological records and climate data at a fine spatial resolution (1.21 km2) to analyze the interannual variability of tree-ring growth and vegetation activity for different forest biomes from 1981 to 2015. Specifically, we assessed the links between tree-ring width indices (TRWi), the Normalized Difference Vegetation Index (NDVI) and a variety of environmental conditions, represented by climatic variables (air temperature, precipitation, evapotranspiration and water balance) and elevation. The impact of these variables on tree growth was assessed by means of the Predictive Discriminant Analysis (PDA). Results reveal a general positive and significant relationship between inter-annual variability of the NDVI at a high spatial resolution (1.21 km2) and tree-ring growth. Maximum correlations between NDVI and tree-ring growth were recorded when cumulative NDVI values were considered, in some cases covering long time periods (6–10 months), suggesting that tree growth is mainly related to Gross Primary Production (GPP) at annual scale. The relationship between tree-ring growth and inter-annual variability of the NDVI, however, strongly varies between forest types and environmental conditions. ; Research projects CGL2014-52135-C03-01, CGL2015-69186-C2-1-R, CGL2015-69985-R, CGL2013-48843-C2-1-R, AGL2014-53822-C2-1-R, (BFU2010-21451), PCIN-2015-220, CGL2016-81706-REDT, CGL2017-82216-R, Spanish Commission of Science and Technology and FEDER, 1560/2015: Herramientas de monitorización de la vegetación mediante modelización ecohidrológica en parques continentales financed by the Red de Parques Nacionales, IMDROFLOOD, Water Works 2014, co-funded call of the European Commission, CROSSDRO financed by the AXIS (Assessment of Cross(X) – sectorial climate Impacts and pathways for Sustainable transformation) JPI-Climate co-funded call of the European Commission and INDECIS, part of ERA4CS, an ERA-NET initiated by JPI Climate, FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR), co-funding by the European Union (Grant 690462). Spanish Commission of Science and Technology and FEDER, and INDECIS, which is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462), Aragon Regional Government, Spanish Ministry of Economy and Competitiveness, Spanish Ministry of Education, Culture and Sport, IJCI-2015-25845, MINECO-FPDI 2013-16600, FJCI 2016-30121, FEDER funds. Xunta de Galicia (PGIDIT06PXIB502262PR, GRC GI-1809, ROCLIGAL-10MDS291009PR), INIA (RTA2006-00117), and Interreg V-A POCTEFA (CANOPEE, 2014-2020-FEDER funds) projects.