Climate forcings on vegetation of the southeastern Yucatan Peninsula (Mexico) during the middle to late Holocene

Climate and vegetation history from the Yucatan Peninsula, southeastern Mexico, are inferred from a mangrove sediment core deposited between the middle and late Holocene (similar to 5600-1700 cal yr B.P.) in the Rio Hondo Delta. Fossil pollen and concentrations of Ca and Fe and Ca/Fe ratio in sediments are used to record changes in vegetation and climate. Palaeoecological and palaeoclimatic interpretations obtained from pollen abundances and associations and Fe/Ca ratio coincide with dynamics of major global forcings of climate change like ITCZ, ENSO and global cooling. Mesic conditions enabled tropical forest expansion during the middle Holocene (similar to 5600-3650 cal yr B.P.), although there were periodic dry episodes at similar to 5200 cal yr B.P. and at similar to 4300 cal yr B.P. that caused disturbance and enabled herbaceous vegetation to expand. Changes in sedimentation and a gradual change from semi-evergreen to dry tropical forest occurred at similar to 3650 cal yr B.P., with increasing ENSO activity and southward migration of the ITCZ during transition of the middle to late Holocene. The driest period and lowest forest cover occurred between similar to 2600 and 2000 cal yr B.P. Data show that over the last two millennia, influence of the ENSO on southeastern Mexico is stronger compared to other proxy-records of climate variability from the Caribbean region.