Refuge theory, ice-age aridity and the history of tropical biotas: an essay in plant geography

Krakau

1993

S. 385-409

3 Abb., zahlr. Lit. Ang.

Bandaufführung

10599S

162638

The following questions are asked in relation to the Quatenary history of tropical biotas; (1) what kinds of disjunction are shown by plants and animals?; (2) what are the features of tropical centres of diversity and where do they occur?; (3) how can geographical differences in diversity be explained?; (4) what was the Quaternary history of tropical environments?; (5) can the contemporary flora and fauna provide clues about the past?; (6) do species respond individualistically to climatic change? Published and unpublished evidence is discussed against a background of what is known about the formerly glaciated Northern lands. It is concluded that; (1) fals analogies have been drawn with north-temperate and Arctic Quaternary history; (2) claims for tropical ice-age aridity are greatly exaggerated and are partly due to erroneous ideas on grassland ecology; this is illustrated by reference to the Lake Victoria basin; (3) the palaeobotanical evidence so far obtained for the tropics is difficult to interpret; (4) some refugia in the Neotropics have been disputed; several in Africa undoubtedly exist, but they are contemporary refugia, and their histories have been complex; (5) some species have responded individualistically to climatic change. Comments are made on the unsatisfactory state of contemporary biogeography, and some suggestions are made for the future.