Lago dell'Accesa Italy 11.7-4.6KYr Pollen Climate Reconstructions ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Lago dell'Accesa Italy 11.7-4.6KYr Pollen Climate Reconstructions LAST UPDATE: 9/2010 (Original receipt by WDC Paleo) CONTRIBUTOR: Walter Finsinger, Centre National de la Recherche Scientifique (CNRS). IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2010-097 WDC PALEO CONTRIBUTION SERIES CITATION: Finsinger, W., et al. 2010. Lago dell'Accesa Italy 11.7-4.6KYr Pollen Climate Reconstructions. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2010-097. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Finsinger, W., D. Colombaroli, J.-L. De Beaulieu, V. Valsecchi, B. Vannière, E. Vescovi, E. Chapron, A.F. Lotter, M. Magny, and W. Tinner. 2010. Early to mid-Holocene climate change at Lago dell'Accesa (central Italy): climate signal or anthropogenic bias? Journal of Quaternary Science, in press, DOI: 10.1002/jqs.1402. ABSTRACT: Despite the high potential of pollen records for climate reconstruction, pollen-climate relationships may be biased due to past and present human activities on the landscape. We use (i) transfer functions based on modern pollen-climate relationships to infer seasonal temperature and summer precipitation for the period 11 500-4500 cal. a BP and (ii) lake-level change records based on different sedimentary proxies in multiple cores that are mainly indicative for summer hydrology at Lago dell'Accesa (central Italy). Quantitative reconstructions indicate lowest summer precipitation during two phases (8500-7700 cal. a BP and after 6000 cal. a BP) and a gradual winter temperature increase from 11 500 to ca. 8000 cal. a BP. Lowest summer precipitation was reconstructed during these phases characterised by vegetation shifts from open forests dominated by summergreen oaks (Quercus) to forests dominated by evergreen oaks (Quercus ilex), which are at present most abundant where summer drought is stronger. Similarly, the lake-level record indicates two long-lasting low summer precipitation phases (8800-7700 and 6400-4400 cal. a BP) that were interrupted by short-term high summer precipitation events. Based on the broad agreement between the pollen-inferred summer precipitation and the low-frequency lake-level changes, we suggest that the duration of the high summer precipitation events may have been too short to maintain drought-sensitive trees, which may have been affected by high mortality rates when summer dry conditions returned. Although past and modern pollen-climate relationships may very likely have been affected by human activities since the Neolithic (i.e. when exploitation of the landscape started), we reject the hypothesis of a significant anthropogenic bias in the pollen-based climate reconstruction. In addition, we suggest that pollen-based and lake-level reconstructions may have different inherent abilities of capturing high- and low-frequency precipitation signals. GEOGRAPHIC REGION: Southern Europe PERIOD OF RECORD: 11,700 - 4600 cal yrs BP FUNDING SOURCES: Swiss National Science Foundation (SNF) to DC, WF and VV (3100AO-102272), SNF Post-doctoral Fellowship (PBBE2-108573) and an AXA Research Fund grant to WF, French CNRS (ECLIPSE Program) and the French ANR (LAMA Project) DESCRIPTION: Pollen-inferred summer precipitation and January temperature for Lago dell'Accesa, central Italy. Lago dell'Accesa, Italy: 42°59.33'N, 10°53.83'E, 157 m a.s.l. Water depth at coring site: 37.5 meters, 0.16 km2 lake surface DATA: Lago dell'Accesa 11.5-4.5KYr Pollen Climate Reconstructions Age: Calendar age, years before present (0 BP = AD 1950) Psmr: Summer Precipitation interpolated at 50 yrs steps and loess smoothed (span 0.1) (mm/season) Tjan: January Temperature interpolated at 50 yrs steps and loess smoothed (span 0.1) (°C) Age Psmr Tjan 4530 97.80 5.58 4612 96.25 5.65 4694 96.86 5.66 4776 99.39 5.58 4858 105.12 5.38 4940 111.04 5.18 5022 116.43 5.01 5104 119.28 4.9 5186 120.44 4.87 5268 119.27 5.01 5350 117.76 5.32 5432 116.90 5.65 5514 117.16 5.95 5596 117.82 6.14 5678 119.21 6.25 5760 121.58 6.13 5842 123.36 5.89 5924 124.57 5.6 6006 127.34 5.34 6088 131.88 5.07 6170 136.99 4.76 6252 140.88 4.4 6334 143.96 4.11 6416 146.05 3.81 6498 144.94 3.56 6580 141.49 3.37 6662 137.56 3.37 6744 134.95 3.46 6826 133.99 3.53 6908 135.26 3.59 6990 137.91 3.62 7072 142.69 3.58 7154 146.31 3.52 7236 147.04 3.48 7318 145.90 3.45 7400 145.15 3.43 7482 143.11 3.49 7564 138.49 3.68 7646 134.24 3.85 7728 132.52 3.96 7810 128.96 4.12 7892 122.54 4.37 7974 116.83 4.6 8056 114.99 4.76 8138 114.47 4.87 8220 114.73 4.9 8302 117.80 4.76 8384 123.05 4.53 8466 129.20 4.27 8548 133.79 4.08 8630 137.18 3.95 8712 139.84 3.93 8794 142.97 3.95 8876 145.61 3.92 8958 147.75 3.71 9040 149.67 3.38 9122 152.32 3.01 9204 154.45 2.72 9286 155.65 2.54 9368 156.58 2.55 9450 159.31 2.79 9532 162.57 3.11 9614 163.64 3.42 9696 162.21 3.58 9778 161.20 3.55 9860 161.04 3.28 9942 160.64 2.97 10024 159.77 2.63 10106 160.89 2.26 10188 163.41 1.9 10270 164.82 1.71 10352 163.77 1.7 10434 161.26 1.67 10516 158.83 1.64 10598 158.17 1.6 10680 157.76 1.58 10762 157.66 1.47 10844 157.47 1.3 10926 158.18 1.13 11008 157.55 1.05 11090 155.86 1.06 11172 154.51 1.12 11254 154.33 1.14 11336 154.35 1.15 11418 154.65 1.17 11500 155.24 1.19