The origin of the grassy habit during the Eocene and the development of C4 grasses during the Miocene/Pliocene boundary are discussed before the origin of primary and secondary grassland in Eurasia and North America are discussed. A comparison shows that both Northern and Southern hemisphere primary grassland originated due to climatic changes to drier conditions during the end of the Eocene, and that modern grassland vegetation types can be traced back to the Oligocene. The Eurasian steppes becomes more fragmented towards the west and south and relicts of primary grassland exists only in the most xerothermic localised habitats in central and western Europe. Secondary grassland clearly due to manmade deforestation, started with the spread of Neolithic husbandry. Southern African grasslands were however not only determined by droughty conditions, but cooler conditions at high altitudes are one of the major driving forces that prevent colonisation by trees of a generally tropical origin.
On the origin of Northern and Southern hemisphere grasslands / G. J., Bredenkamp; Spada, Francesco; E., Kazmierczak. - In: PLANT ECOLOGY. - ISSN 1385-0237. - STAMPA. - 163:2(2002), pp. 209-229. (Intervento presentato al convegno 16th International Botanical Congress tenutosi a ST LOUIS, MISSOURI, USA nel 1-6 August 1999) [10.1023/a:1020957807971].
On the origin of Northern and Southern hemisphere grasslands
SPADA, Francesco;
2002
Abstract
The origin of the grassy habit during the Eocene and the development of C4 grasses during the Miocene/Pliocene boundary are discussed before the origin of primary and secondary grassland in Eurasia and North America are discussed. A comparison shows that both Northern and Southern hemisphere primary grassland originated due to climatic changes to drier conditions during the end of the Eocene, and that modern grassland vegetation types can be traced back to the Oligocene. The Eurasian steppes becomes more fragmented towards the west and south and relicts of primary grassland exists only in the most xerothermic localised habitats in central and western Europe. Secondary grassland clearly due to manmade deforestation, started with the spread of Neolithic husbandry. Southern African grasslands were however not only determined by droughty conditions, but cooler conditions at high altitudes are one of the major driving forces that prevent colonisation by trees of a generally tropical origin.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.