Alfaro Reyna T., Retana J., Martínez-Vilalta J. (2018) Is there a substitution of Pinaceae by Fagaceae in temperate forests at the global scale?. Global and Planetary Change. 166: 41-47.EnllaçDoi: 10.1016/j.gloplacha.2018.04.001
Reports on forest decline, changes in species composition and the distribution of forests in response to changes in climate and land use are increasing worldwide. Temperate forests are largely dominated by two tree families: Pinaceae and Fagaceae. These two families have distinct functional properties and different responses to environmental factors. Several local and regional assessments, particularly in Europe, have found that species of Fagaceae are invading areas previously dominated by Pinaceae. The main aim of this synthesis study is to analyze the relative dynamics of Pinaceae and Fagaceae species in temperate forests around the world, with the following specific objectives: (1) establish if there is a consistent directional substitution of Pinaceae by Fagaceae worldwide; and (2) determine whether these directional changes are associated with specific climatic conditions or certain geographic regions, reflecting differences in historical forest management and land use. A bibliographic review was performed and 51 papers were found that met the search criteria, including a total of 121 case studies in which the relative dynamics of Pinaceae and Fagaceae were evaluated. Our results show that the relative abundance of Fagaceae increased in 71% of cases (P → F dynamics), whereas Pinaceae relative abundance increased in 17% of cases (F → P) and 12% of cases did not show clear changes. Increases of Fagaceae relative to Pinaceae were less clear in areas where vegetation dynamics were driven by natural disturbances. Our results indicate a widespread increase in dominance of Fagaceae species at the expense of Pinaceae across northern temperate forests, with the exception of Eastern North America. The potential implications for ecosystem function and forest resilience under ongoing climate change are large and clearly deserve further study. © 2018 Elsevier B.V.
Martínez-Vilalta J. (2018) The rear window: Structural and functional plasticity in tree responses to climate change inferred from growth rings. Tree Physiology. 38: 155-158.EnllaçDoi: 10.1093/treephys/tpy008
[No abstract available]
Poyatos R., Sus O., Badiella L., Mencuccini M., Martínez-Vilalta J. (2018) Gap-filling a spatially explicit plant trait database: Comparing imputation methods and different levels of environmental information. Biogeosciences. 15: 2601-2617.EnllaçDoi: 10.5194/bg-15-2601-2018
The ubiquity of missing data in plant trait databases may hinder trait-based analyses of ecological patterns and processes. Spatially explicit datasets with information on intraspecific trait variability are rare but offer great promise in improving our understanding of functional biogeography. At the same time, they offer specific challenges in terms of data imputation. Here we compare statistical imputation approaches, using varying levels of environmental information, for five plant traits (leaf biomass to sapwood area ratio, leaf nitrogen content, maximum tree height, leaf mass per area and wood density) in a spatially explicit plant trait dataset of temperate and Mediterranean tree species (Ecological and Forest Inventory of Catalonia, IEFC, dataset for Catalonia, north-east Iberian Peninsula, 31 900 km2). We simulated gaps at different missingness levels (10-80 %) in a complete trait matrix, and we used overall trait means, species means, k nearest neighbours (kNN), ordinary and regression kriging, and multivariate imputation using chained equations (MICE) to impute missing trait values. We assessed these methods in terms of their accuracy and of their ability to preserve trait distributions, multi-trait correlation structure and bivariate trait relationships. The relatively good performance of mean and species mean imputations in terms of accuracy masked a poor representation of trait distributions and multivariate trait structure. Species identity improved MICE imputations for all traits, whereas forest structure and topography improved imputations for some traits. No method performed best consistently for the five studied traits, but, considering all traits and performance metrics, MICE informed by relevant ecological variables gave the best results. However, at higher missingness (> 30 %), species mean imputations and regression kriging tended to outperform MICE for some traits. MICE informed by relevant ecological variables allowed us to fill the gaps in the IEFC incomplete dataset (5495 plots) and quantify imputation uncertainty. Resulting spatial patterns of the studied traits in Catalan forests were broadly similar when using species means, regression kriging or the best-performing MICE application, but some important discrepancies were observed at the local level. Our results highlight the need to assess imputation quality beyond just imputation accuracy and show that including environmental information in statistical imputation approaches yields more plausible imputations in spatially explicit plant trait datasets. © 2018 Author(s).
Roces-Díaz, J.V., Vayreda, J., Banqué-Casanovas, M., Díaz-Varela, E., Bonet, J.A., Brotons, L., de-Miguel, S., Herrando, S., Martínez-Vilalta, J. (2018) The spatial level of analysis affects the patterns of forest ecosystem services supply and their relationships. Science of the Total Environment. 626: 1270-1283.EnllaçDoi: 10.1016/j.scitotenv.2018.01.150
Serra-Maluquer X., Mencuccini M., Martínez-Vilalta J. (2018) Changes in tree resistance, recovery and resilience across three successive extreme droughts in the northeast Iberian Peninsula. Oecologia. : 1-12.EnllaçDoi: 10.1007/s00442-018-4118-2
Understanding which variables affect forest resilience to extreme drought is key to predict future dynamics under ongoing climate change. In this study, we analyzed how tree resistance, recovery and resilience to drought have changed along three consecutive droughts and how they were affected by species, tree size, plot basal area (as a proxy for competition) and climate. We focused on the three most abundant pine species in the northeast Iberian Peninsula: Pinus halepensis, P. nigra and P. sylvestris during the three most extreme droughts recorded in the period 1951–2010 (occurred in 1986, 1994, and 2005–2006). We cored trees from permanent sample plots and used dendrochronological techniques to estimate resistance (ability to maintain growth level during drought), recovery (growth increase after drought) and resilience (capacity to recover pre-drought growth levels) in terms of tree stem basal area increment. Mixed-effects models were used to determine which tree- and plot-level variables were the main determinants of resistance, recovery and resilience, and to test for differences among the studied droughts. Larger trees were significantly less resistant and resilient. Plot basal area effects were only observed for resilience, with a negative impact only during the last drought. Resistance, recovery and resilience differed across the studied drought events, so that the studied populations became less resistant, less resilient and recovered worse during the last two droughts. This pattern suggests an increased vulnerability to drought after successive drought episodes. © 2018 Springer-Verlag GmbH Germany, part of Springer Nature
Stojnić S., Suchocka M., Benito-Garzón M., Torres-Ruiz J.M., Cochard H., Bolte A., Cocozza C., Cvjetković B., De Luis M., Martinez-Vilalta J., Ræbild A., Tognetti R., Delzon S. (2018) Variation in xylem vulnerability to embolism in European beech from geographically marginal populations. Tree Physiology. 38: 173-185.EnllaçDoi: 10.1093/treephys/tpx128
Climate change is expected to increase the frequency and intensity of droughts and heatwaves in Europe, leading to effects on forest growth and major forest dieback events due to hydraulic failure caused by xylem embolism. Inter-specific variability in embolism resistance has been studied in detail, but little is known about intra-specific variability, particularly in marginal populations. We evaluated 15 European beech populations, mostly from geographically marginal sites of the species distribution range, focusing particularly on populations from the dry southern margin. We found small, but significant differences in resistance to embolism between populations, with xylem pressures causing 50% loss of hydraulic conductivity ranging from -2.84 to -3.55 MPa. Significant phenotypic clines of increasing embolism resistance with increasing temperature and aridity were observed: the southernmost beech populations growing in a warmer drier climate and with lower habitat suitability have higher resistance to embolism than those from Northern Europe growing more favourable conditions. Previous studies have shown that there is little or no difference in embolism resistance between core populations, but our findings show that marginal populations have developed ways of protecting their xylem based on either evolution or plasticity. © The Author 2017. Published by Oxford University Press. All rights reserved.
Vilà-Cabrera, A., Coll, L., Martínez-Vilalta, J., Retana, J. (2018) Forest management for adaptation to climate change in the Mediterranean basin: A synthesis of evidence. Forest Ecology and Management. 407: 16-22.EnllaçDoi: 10.1016/j.foreco.2017.10.021
Adams, H.D., Zeppel, M.J.B., Anderegg, W.R.L., Hartmann, H., Landhäusser, S.M., Tissue, D.T., Huxman, T.E., Hudson, P.J., Franz, T.E., Allen, C.D., Anderegg, L.D.L., Barron-Gafford, G.A., Beerling, D.J., Breshears, D.D., Brodribb, T.J., Bugmann, H., Cobb, R.C., Collins, A.D., Dickman, L.T., Duan, H., Ewers, B.E., Galiano, L., Galvez, D.A., Garcia-Forner, N., Gaylord, M.L., Germino, M.J., Gessler, A., Hacke, U.G., Hakamada, R., Hector, A., Jenkins, M.W., Kane, J.M., Kolb, T.E., Law, D.J., Lewis, J.D., Limousin, J.-M., Love, D.M., Macalady, A.K., Martínez-Vilalta, J., Mencuccini, M., Mitchell, P.J., Muss, J.D., O'Brien, M.J., O'Grady, A.P., Pangle, R.E., Pinkard, E.A., Piper, F.I., Plaut, J.A., Pockman, W.T., Quirk, J., Reinhardt, K., Ripullone, F., Ryan, M.G., Sala, A., Sevanto, S., Sperry, J.S., Vargas, R., Vennetier, M., Way, D.A., Xu, C., Yepez, E.A., McDowell, N.G. (2017) A multi-species synthesis of physiological mechanisms in drought-induced tree mortality. Nature Ecology and Evolution. 1: 1285-1291.EnllaçDoi: 10.1038/s41559-017-0248-x
Doblas-Miranda, E., Alonso, R., Arnan, X., Bermejo, V., Brotons, L., de las Heras, J., Estiarte, M., Hódar, J.A., Llorens, P., Lloret, F., López-Serrano, F.R., Martínez-Vilalta, J., Moya, D., Peñuelas, J., Pino, J., Rodrigo, A., Roura-Pascual, N., Valladares, F., Vilà, M., Zamora, R., Retana, J. (2017) A review of the combination among global change factors in forests, shrublands and pastures of the Mediterranean Region: Beyond drought effects. Global and Planetary Change. 148: 42-54.EnllaçDoi: 10.1016/j.gloplacha.2016.11.012
Galiano, L., Timofeeva, G., Saurer, M., Siegwolf, R., Martínez-Vilalta, J., Hommel, R., Gessler, A. (2017) The fate of recently fixed carbon after drought release: Towards unravelling C storage regulation in Tilia platyphyllos and Pinus sylvestris. Plant Cell and Environment. : 0-0.EnllaçDoi: 10.1111/pce.12972
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