Long-term vegetation dynamics in a Neotropical coastal mountain: the late deglacial history of Cofre de Perote (Eastern central Mexico)

Abstract

Knowledge of deglacial history in high-altitude environments of the northern Neotropics remains limited, because most research has been focussed on lower elevations. This study presents a palaeoecological reconstruction of vegetation dynamics during the Early to Middle Holocene from a high-elevation peatland (3770 m asl) on Cofre de Perote volcano, located at the eastern end of the Trans-Mexican Volcanic Belt. A sedimentary sequence was analysed through palynological analyses, supported by charcoal, magnetic susceptibility, and titanium data. The pollen record, spanning 10.3–4.9 cal kyr BP, is divided into four pollen zones: (i) Between 10.3 and 10 cal kyr BP, low pollen values indicate poor preservation and periglacial conditions; (ii) From 10 to 9.5 cal kyr BP, pollen of herbaceous taxa related to pine forest and alpine grassland suggest early vegetation colonisation near 3700 m asl; (iii) Between ~9.5 and 7.6 cal kyr BP, pollen assemblages suggests alpine grassland development near the coring site, while high Cyperaceae and Isoëtes values around 8 cal kyr BP suggest peatland development; (iv) From ~7.6 to 4.9 cal kyr BP, increased Pinus and decreased herbaceous pollen could imply pine forest establishment at similar to modern elevations. These findings, supported by previous records, suggest that Early Holocene forests at Cofre de Perote were more stable and reached higher elevations than those further inland. Additionally, considering long-distance transport of wind-driven taxa is crucial for interpreting pollen assemblages of high altitudes locations following deglaciation. The presence of Picea pollen reflects a past vegetation community without modern analogue and indicates the volcano’s role as a microrefugia during the Early Holocene.