DOI: 10.5061/dryad.df3sn
title: Data from: The past ecology of Abies alba provides new perspectives on future responses of silver fir forests to global warming

description: Paleoecology can provide valuable insights into the ecology of species
 that complement observation and experiment-based assessments of
 climate-impact dynamics. New paleoecological records (e.g. pollen,
 macrofossils) from the Italian Peninsula suggest a much wider climatic
 niche of the important European tree species Abies alba (silver fir) than
 observed in its present spatial range. To explore this discrepancy between
 current and past distribution we analyse climatic data (e.g. temperature,
 precipitation, frost, humidity, sunshine) and vegetation-independent
 paleoclimatic reconstructions (e.g. lake levels, chironomids) and use
 global coupled carbon-cycle climate (NCAR CSM1.4) and dynamic vegetation
 (LANDCLIM) modelling. The combined evidence suggests that during the
 mid-Holocene (ca. 6000 years ago), prior to humanization of vegetation, A.
 alba formed forests under conditions that exceeded modern (1961-1990)
 upper temperature limit of the species by ca. 5-7 {degree sign}C (July
 means). Annual precipitation during this natural period was comparable to
 today (&gt;700-800 mm), with drier summers and wetter winters. In the
 meso-mediterranean to sub-mediterranean forests A. alba co-occurred with
 thermophilous taxa such as Quercus ilex, Q. pubescens, Olea europaea,
 Phillyrea, Arbutus, Cistus, Tilia, Ulmus, Acer, Hedera helix, Ilex
 aquifolium, Taxus, and Vitis. Results from the last interglacial (ca.
 130,000-115,000 BP), when human impact was negligible, corroborate the
 Holocene evidence. Thermophilous Mediterranean A. alba stands became
 extinct during the last 5000 years when land-use pressure and specifically
 excessive anthropogenic fire and browsing disturbance increased. Our
 results imply that the ecology of this key European tree species is not
 yet well understood. On the basis of the reconstructed realized climatic
 niche of the species, we anticipate that the future geographic range of A.
 alba may not contract regardless of migration success, even if climate
 should become significantly warmer than today with summer temperatures
 increasing by up to 5-7{degree sign}C, as long as precipitation does not
 fall below 700-800 mm/year, and disturbance (e.g. fire, browsing) does not
 become excessive. Our finding contradicts recent studies that projected
 range contractions under global-warming scenarios, but did not factor how
 millennia of human impacts reduced the realized climatic niche of A. alba.
description: Figure 2
 dataClimate data shown in
 figure 2. The columns present 1) site name, 2) country (CH = Swizerland,
 IT = Italy), 3) site elevation, 3) site longitude, 4) site latitude, 5)
 mean July temperature, 6) standard deviation of July temperature, 7)
 annual precipitation, 8) standard deviation of annual precipitation.
 Temperature and precipitation for study sites in Switzerland was obtained
 from interpolated climate station data (1961-1990; Thornton et al. 1997;
 data source: Swiss Federal Institute for Forest, Snow, and Landscape
 Research WSL). For study sites in Italy, temperatures were obtained from
 the nearest weather station (1961-1990; Desiato et al. 2007; data source:
 SCIA System). Data for Monticchio were obtained from ENEA (Italian
 National Agency for New Technologies, Energy and Sustainable
 Development).Fig2_data.csvFigure 3 dataChironomid-inferred temperature reconstructions shown in figure 3. The columns present 1) site name, 2) calibrated years before present of the sample, 3) the chironomid transfer-function-inferred summer temperature temperature, 4) the inferred temperature minus the sample-specific standard error of prediction, 5) the inferred temperature plus the sample-specific standard error of prediction.Fig3_data.csvFigure 4 dataClimate conditions simulated by a global climate model (NCAR CSM1.4) during the mid-Holocene (6000 cal yr BP) and the preindustrial period in select grid cells. 1) grid cell coordinates, 2) period (preindustrial or 6 cal yr BP), 3) month (Jan-Dec), 4) numbered months (1-12), 5) Precipitation (mm/month), and 6) Temperature (°C).Fig4_data.csvFigures 6 & 7 dataPollen percentage data used in DCA analysis for figures 6 and 7. Column 1) ID - sample number, colum 2) site name, column 3) data type - (0=present,1=Holocene, 2=pre-Holocene), columns 4-187 - pollen type.Fig6-7.csvFigure 8 dataAnnual temperature precipitation data within the extant range of Abies alba used to make histograms of precipitation abundance frequencies and mean July temperature frequencies. Data are from grid cells of the Climatic Research Unit Ten Minute Climatology (http://www.cru.uea.ac.uk/cru/data/hrg/tmc/). Column 1) precipitation abundances of each individual grid cell within the Abies alba range, column 2) mean July temperature in each individual grid cell within the Abies alba range.Fig8_data.csvFigure 9a dataSummarized output from the LandClim dynamic vegetation model from Lago di Massaciuccoli. Columns show the simulation year, and the simulated biomass of Abies alba, Quercus ilex, Quercus suber, Quercus cerris, species with Quercus robur type pollen (Quercus robur, Quercus petraea, and Quercus pubescens), Fraxinus ornus, all other deciduous species (see Henne et al. 2013, Landscape Ecology, for a full list), Pinus halepensis, and all other broadleaved evergreen species.Fig9a data.csv