Research paper Palaeobiogeography of Pinus nigra Arn. subsp. salzmannii (Dunal) Franco in the north- western Mediterranean Basin: A review based on macroremains Paul Roiron a , Lucie Chabal a , Isabel Figueiral a, b , Jean- Frédéric Terral a , Adam A. Ali a, ⁎ a Centre de BioArchéologie et d'Écologie, UMR 5059, Institut de Botanique, 163 rue A. Broussonet, 34090 Montpellier, France b INRAP Méditerranée, 3 rue de l'Acropole, Lot. Actipolis, 34420 Villeneuve-les-Béziers, France abstract article info Article history: Received 9 July 2012 Received in revised form 21 February 2013 Accepted 6 March 2013 Available online 16 March 2013 Keywords: travertine cone imprints charcoal Salzmann pine regional extinction biological conservation The palaeobiogeography of Pinus nigra subsp. salzmannii is investigated in an attempt to understand the environ- mental mechanisms responsible for its present-day fragmented distribution. A synthesis of data based on cone imprints from travertine deposits and wood charcoal from archaeological sites suggests that, in the past (Holocene), P. nigra subsp. salzmannii had a larger distribution in the north-western Mediterranean Basin. This species has disappeared from eastern France probably as a result of the competition with other ligneous species, such as Quercus ilex and Pinus halepensis, which were favoured by anthropogenic disturbances during the Late Holocene. Current environmental changes, including increasing drought and fire events, will further contribute to the regression of P. nigra subsp. salzmannii populations. The safeguard of this pine in the Mediterranean land- scapes relies on sustained national and European conservation programs. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Recent international proposals on biodiversity conservation en- abled us to recognise the mechanisms responsible for the loss of biodi- versity in space and time (International conferences of Rio, 1992; Johannesburg, 2002; Copenhagen, 2009). As a result, the development of studies allowing the setting up of conservation strategies has be- come a clear priority. Ongoing climate changes coupled with increasing human distur- bance imply that constructive decisions must be taken based on data obtained via interdisciplinary research. Palaeoecological investigations identify historical and ecological processes involved in the evolution dynamics of plant and animal communities in relation to climate change and human disturbance. The potential of palaeoecological records as providers of key information on habitat fragmentation, changing disturbance regimes and species resilience has been given growing consideration in terms of biological conservation purposes (Willis and Birks, 2006). Pinus nigra subsp. salzmannii (Salzmann pine) belongs to the Sylvestres subsection (Richardson, 1998). In the Mediterranean Basin, it presents a fragmented distribution in Spain and France (Figs. 1 and 2) mainly on dolomitic or calcareous substrates and also on siliceous substrates. Its natural habitat is frequently destroyed by natural or human induced fires (Trabaud and Campant, 1991). Burnt areas are rapidly colonised by competitive species such as Pinus pinaster, Pinus halepensis, Quercus ilex and/or Quercus coccifera, while the Salzmann pine regenerates with difficulty (Trabaud and Campant, 1991; Escudero et al., 1997; Rodrigo et al., 2004). In Southern Spain, the regeneration of P. nigra subsp. salzmannii is also limited by the den- sity of the herbaceous cover, the severity of the summer drought and seed predation (Tiscar Oliver, 2003; Tiscar and Linares, 2011). The sur- vival of this pine species is also genetically endangered due to natural hybridization with P. nigra subsp. nigra, abundantly planted during the last century for soil restoration purposes and for wood exploitation (Vautrin and Royer, 1998; Fady, 2007). Consequently, the Salzmann pine represents a major European priority in terms of habitat conserva- tion. Its forests are included in the EU listing of natural habitats requir- ing specific conservation measures (Council Directive 92/43/EEC, 1992; Leone and Lovreglio, 2004; Fady et al., 2010). The past dynamics of Pinus nigra subsp. salzmannii and consequently its palaeobiogeography, are poorly documented because, for the moment, only cone fossils and imprints allow its identification. As explained below, wood-charcoal identification discriminates the sub- section Sylvestres but not the species included under this nomenclature. Pollen proxy is often restricted to the distinction between Haploxylon and Diploxylon pines (e.g. Reille, 1992; Nakagawa et al., 2000; Pini, 2002; Schmidt et al., 2002; Finsinger and Tinner, 2006; Muller et al., 2006), and generic identifications (Pinus) are favoured by the majority of specialists (Willis et al., 1998). This is why we seldom refer to the pollen data in our synthesis. We assemble data gathered from the anal- ysis of macroremains uncovered in Spain and Southern France, i.e. cone Review of Palaeobotany and Palynology 194 (2013) 1–11 ⁎ Corresponding author. Tel.: +33 4 99 23 21 80; fax: +33 4 67 54 35 37. E-mail address: ali@univ-montp2.fr (A.A. Ali). 0034-6667/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.revpalbo.2013.03.002 Contents lists available at SciVerse ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo