Orbital- and sub-orbital-scale climate impacts on vegetation of the western Mediterranean basin over the last 48,000 yr

Abstract

High-resolution pollen analysis of Alborán Sea core MD95-2043 provides a 48-ka continuous vegetation record that can be directly correlated with sea surface and deep-water changes. The reliability of this record is supported by comparison with that of Padul (Sierra Nevada, Spain). Marine Isotope Stage (MIS) 3 was characterised by fluctuations in Quercus forest cover in response to Dansgaard-Oeschger climate variability. MIS 2 was characterised by the dominance of semi-desert vegetation. Despite overall dry and cold conditions during MIS 2, Heinrich events (HEs) 2 and 1 were distinguished from the last glacial maximum by more intensely arid conditions. Taxon-specific vegetation responses to a tripartite climatic structure within the HEs are observed. In MIS 1, the Bölling-Allerød was marked by rapid afforestation, while a re-expansion of semidesert environments occurred during the Younger Dryas. The maximum development of mixed Quercus forest occurred between 11.7 and 5.4 cal ka BP, with forest decline since 5.4 cal ka BP. On orbital timescales, a long-term expansion of semi-desert vegetation from MIS 3 into MIS 2 reflects global ice-volume trends, while Holocene arboreal decline reflects summer insolation decrease. The influence of precession on the amplitude of forest development and vegetation composition is also detected.

Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

“…4) as shown by the progressive decrease in natural forest species and the increase in xerophytes such as Artemisia. This agrees with previous 15 paleoclimatic studies in the western Mediterranean, which document a progressive aridification trend since ~7000 cal yr BP (Carrión et al, 2002;Fletcher and Sánchez Goñi, 2008;Jalut et al, 2009;Carrión et al, 2010;Anderson et al, 2011;Jiménez-Moreno et al, 2012. Jiménez- Moreno et al ( , 2015 suggested that semidesert expansion and Mediterranean forest decline during the late Holocene in this area could be explained by decreasing summer insolation (Laskar et al, 2004;Fig.…”

Abrupt climate changes during Termination III in Southern Europe

“…The freshwater glacial melt release and AMOC shutdown leave a clear climatic fingerprint on the Iberian Peninsula during stadial events of T-I and MIS 3 because weakened heat transport shifted storm tracks and led to extremely dry conditions (21,22). This connection results from the expansion of the polar vortex during AMOC shutdowns, which lead to the southward arrival of polar or continental air outbreaks.…”

Abrupt climate changes of the last deglaciation detected in a Western Mediterranean forest record

“…4) was obtained employing standard methods of pollen extraction, identification and counts reported in Fletcher and Sanchez Goñi (2008 (Fig. 4).…”

“…5) reveals a long-term recovery of forest populations across the last glacial-interglacial transition, with minimum values (<10%) during the H1 interval (as defined on the basis of marine climatic tracers in the same core (Cacho et al, 2006(Cacho et al, , 1999Fletcher and Sanchez Goñi, 2008)), intermediate values (15-50%) during the Lateglacial and Preboreal (PB), and high values (>50%) after 10.6 cal ka BP. Following the expansion of forest populations at the end of H1, discrete intervals of reduced forest development are detected (in all cases by the values of at least two samples) throughout the Lateglacial and early Holocene, centred on 14.…”

“…The preservation of terrestrial pollen and spores in long, continuous, and high-sedimentation rate marine cores of the Alboran Sea therefore provides an important line of information regarding vegetation and climate changes during the deglaciation associated with events of meltwater discharges and perturbation of the North Atlantic circulation (Combourieu Nebout et al, , 2002Fletcher and Sanchez Goñi, 2008). In this study we present evidence for multicentennial-scale fluctuations in temperate forest development and reconstructed climatic parameters (annual precipitation, winter and summer mean temperatures) during the last deglaciation period, i.e.…”