Relationship between modern pollen, vegetation, and climate between the latitudes

FLAVIA A. QUINTANA; MARTA M. PAEZ

REVIEW OF PALAEOBOTANY AND PALYNOLOGY

ELSEVIER SCIENCE BV

Lugar: Holanda; Año: 2010

0034-6667

The aim of this research was two-fold, to examine how plants and major vegetation types are represented in modern pollen assemblages between 51º16’12”S and 53º45’S and  to evaluate how these pollen assemblages are related to climate parameters. A modern pollen data set of forty-eight surface soil samples, and mean annual and monthly temperature and precipitation values were analyzed applying unconstrained cluster and canonical analyses. The major vegetation types are represented in the modern pollen spectra as Subantarctic forest, forest-steppe transition, and Festuca gracillima steppe. The Subantarctic forest, characterized by >60-90% of Nothofagus -type pollen, was represented by two pollen assemblages subgroups due to differences in physiognomy and intensity of human impact. The forest-steppe transition was characterized by 40% each for Poaceae and Nothofagus dombeyi –type, respectively. The Festuca gracillima steppe was represented by either >50% of Poaceae pollen or by <50% of Poaceae pollen coupled with higher percentages of cushion plants pollen. Some grass steppe pollen assemblages showed significant amounts of Empetrum rubrum (~20%) probably related to disturbance due to human activity. A 32% of variance in the modern pollen data set was associated with climatic variables. The forest and forest-steppe transition pollen assemblages were strongly related to August precipitation. A small amount of variance was associated with June and August temperatures, indicating the oceanic influence on winter temperatures. Pollen assemblages of different vegetation units placed closed to the coast were differentiated from those farther inland. A second analysis revealed the weak influence of the January temperature, mainly related to Festuca gracillima steppe pollen assemblages.