A lacustrine record of early Holocene watershed events and vegetation history, Corvara in Badia Dolomites (Italy) LISA BORGATTI, 1 CESARE RAVAZZI, 2 * MARTA DONEGANA, 2 ALESSANDRO CORSINI, 1 MAURO MARCHETTI 1 and MAURO SOLDATI 1 1 Dipartimento di Scienze della Terra, Universita ` degli Studi di Modena e Reggio Emilia, Modena, Italy 2 CNR—Istituto per la Dinamica dei Processi Ambientali, Milan, Italy Borgatti, L., Ravazzi, C., Donegana, M., Corsini, A., Marchetti, M. and Soldati, M. 2006. A lacustrine record of early Holocene watershed events and vegetation Corvara in Badia, Dolomites (Italy). J. Quaternary Sci., Vol. 22 pp. 173–189. ISSN 0267–8179. Received 22 December 2005; Revised 30 March 2006; Accepted 24 April 2006 ABSTRACT: The early–middle Holocene lacustrine succession of Corvara in Badia (Italian Dolo- mites,1521 m a.s.l.) records landslides and other watershed events before the onset of human pressure. The sensitivity of this archive to relate climate change, watershed processes and vegetation dynamics in the catchment has been explored through a stratigraphic study, including the analysis of sedimentological features, magnetic properties, palaeobotanical records and radiocarbon dating. A palaeolake existed between 10.1 k and 7 k cal. yr BP and was surrounded by a dense conifer forest. Long-term forest dynamics driven by ecological processes and by climatic conditions favourable to upward forest expansion is recorded throughout the pollen record. Within the fine clastic sedimen- tation, distinct layers enriched in organic debris of terrestrial origin have been attributed to instant eventsproducedby mass movements.Their age fits the chronologyof large landslide events already known in the catchment, enabling correlation of the field evidence of landslides with the lacustrine record. Landslide frequency is controlled by geological and structural factors, but it is significantly modulated by the centennial–millennial climatic phases that characterise the Holocene in the Alps.The taphonomical properties of pollen and macroremains provided valuable insight on the mechanism of watershed processes. Copyright# 2006 John Wiley & Sons, Ltd. KEYWORDS: landslide events; Holocene lacustrine record; long-term vegetation dynamics; Dolomites; Italy Introduction Study of the relationships between environment, climate and temporaldistribution of landslides from the end of the Last Glacial Maximum (LGM) to the presentis relevantfor understanding the frequency and magnitude of mass wasting phenomenaover a broad timescale.Many authorshave pointed out the influenceof climate and environmental changeson the occurrence of masswasting processes and many investigations have been carried out on this topic in Europe (Lateltin et al., 1997,Matthews et al., 1997;Borgatti et al., 2001; Soldati et al., 2004). Outside Europe, case studies from Africa (Busche,2001; Thomas,1999),northern and southern America (Bovis and Jones, 1992; Trauth et al., 2000; Smith, 2001; Holm et al., 2004), Asia (Sidle et al., 2004) and Oceania (Crozier, 1997) have been recently published. The widespread occurrence of lacustrine successions in sensitiveareas affected by slope instabilityallows these relationships to be investigated with high time resolution. The stratigraphic record provides a long-term perspective of landslide activity and of the boundary environmental con- ditions, and possibly can give hints on the causal factors that actually triggered the mass-wasting phenomena. A recent stud in the western Swiss Alps focused on the correlation between slope movements, climatic changes and land use in prehistoric and historic times based on the analysis of lacustrine records (Dapples et al., 2002). Age determinations of rock-avalanche depositsand investigation ofthe sedimentsof associated landslide-dammed lakes provided valuable information on Late Pleistocene and Holocene climate change in northwestern Argentina (Trauth et al., 2003).Here, landslide activity is related to periods of wetter and more seasonal climate. Eden and Page (1998) analysed a high-resolution lacustrine record o storm-generated sediments in a steep hilly and landslide-prone area in New Zealand. Although the inorganic sediments are an integration of a number of processes, landsliding accounts for the majorityof the sedimentmobilised by storm events represented bydepositsthickerthan 3 mm.A Holocene sedimentary record of debris flows causing turbidity currents and graded deposition of sand and allochthonous organic debris in lake sediments has been described in non-forested JOURNAL OF QUATERNARY SCIENCE (2007) 22(2) 173–189 Copyright ß 2006 John Wiley & Sons, Ltd. Published online 6 December 2006 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jqs.1039 * Correspondence to: C. Ravazzi,CNR—Istituto per la Dinamica dei Processi Ambientali, Via Pasubio 5, 24044 Dalmine, Italy. E-mail: cesare.ravazzi@idpa.cnr.it