Triumph and Fall of the Wet, Warm, and Never-More-Diverse Temperate Forests (Oligocene-Pliocene)

Edoardo Martinetto, Nareerat Boonchai, Fridgeir Grimsson, Paul Joseph Grote, Gregory Jordan, Marianna Kovácová, Lutz Kunzmann, Zlatko Kvaček, Christopher Yu-Sheng Liu, Arata Momohara, Yong-Jiang Huang, Luis Palazzesi, Mike Pole, Ulrich Salzmann

Large areas of Earth’s continents were covered by temperate forests before the dramatic increase of the human population in the past two millennia. Prior to human expansion, temperate forests were more extensive in the Neogene (23–2.6 Ma) when climate at the middle latitudes was slightly warmer and more equable than at the present. These temperate forests exhibited a high diversity of plant taxa, higher than today in several geographical areas. Such high diversity in the past can be explained by two reasons. First, angiosperms originated in the Cretaceous and underwent an important phylogenetic diversification during and shortly after that period. These new plant lineages easily dispersed between North America and Eurasia, and biogeographic range expansions continued across other continents. Second, since the Eocene/Oligocene transition (c. 34 Ma), several members of tropical/subtropical lineages adapted to cooler conditions and entered the warmer temperate realm. An equable climate with abundant precipitation in widespread areas provided a suitable habitat for moisture-requiring woody plants. The higher floristic diversity in the Neogene compared to the present is best illustrated by European fossil plants and, to a lesser extent, by those in North America. The area covered by temperate forests in South America decreased consistently after the late Miocene, and the dominant woody plants of the Neogene remained only in the westernmost regions. A floristic impoverishment is not clearly documented in Australia, where there was a much higher diversity of conifers in the Oligocene-Miocene than today. Beginning some 6 million years ago, several global intervals of colder and/or drier climate reduced the habitat of those taxa that required nonfreezing temperatures and moisture, finally resulting in a large mass extirpation/extinction of thermophilous plants in western Eurasia. This turnover occurred primarily between 3.5 and 1.0 million years ago. The trend was different in eastern Eurasia where extirpation/extinction has been rather limited. In conclusion, the mid-latitudes of all the continents witnessed a triumph of the extension and diversity of temperate forests from about 34 to 3 million years ago (Oligocene-Pliocene) and, in many temperate places, these grew under wetter and warmer conditions than today.

Department für Botanik und Biodiversitätsforschung
Externe Organisation(en)
Università degli Studi di Torino, Mahasarakham University, Nakhon Ratchasima Rajabhat University, University of Tasmania, Comenius University in Bratislava, University of Missouri–Kansas City, Chiba University, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN), Queensland Herbarium, Brisbane Botanic Gardens, Toowong, Australia, Northumbria University, Senckenberg Gesellschaft für Naturforschung (SGN), Charles University Prague
Anzahl der Seiten
ÖFOS 2012
105112 Historische Geologie, 105117 Paläobotanik, 106008 Botanik
ASJC Scopus Sachgebiete
Palaeontology, Plant Science
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