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Asia: habitats, faunal barriers

Pleistocene landbridges and rainforest extent within the distribution area of Asian Loridae

Approximate extent of Pleistocene land during maximum glaciation, 18 000 years ago, based on Pelz, 1999 (including historical data from Jonathan Adams, University of Adelaide), Ripley (1969), Dawson (1992) Guthrie (1990) and Bartholomew (1979) (present day depth of sea ground).
Sources of habitat information: Pleistocene rainforest based on Pelz, 1999, extent of glaciers: Carlton 1985, active sand dunes: Dawson 1992.

  Wallace´s Line, Weber´s Line: faunal barriers consisting of deeper areas in which, during Pleistocene, no land bridges existed; separate regions without faunal exchange contributed to the development of areas with a distinct fauna. In general, the climate was probably dryer than today because a lot of water was included in glaciers, and the general extent of rainforest was therefore more limited than today (Pelz 1999). According to Ripley (1969) in certain regions the climate at times was was more humid; the landbridge between India and Sri Lanka for instance was probably covered with deciduous forest over some time or, in even more humid periods, with tropical rain forest, allowing several periods of migration of forest fauna between India and Sri Lanka. Distribution of primate species and subspecies in Vietnam indicate the former existence of a faunal barrier from east to west at about 14ºN to 17ºN (see map of present state of distribution area, next figure), possibly associated with a Pleistocene glacial interval of reduced temperature, reduced rainfall and increased seasonality (Fooden 1996, quoting Heaney 1991). Climatic changes also allowed temporal spreading of cold-adapted mountain fauna and flora representatives of populations which are presently found in the Himalaya to Sri Lankan Highland (Ripley 1969)

Present geography and natural rainforest extent
Rainforest extent based on Ripley (1969); deforestation not considered.





  Biogeographical provinces, based on Eudey, 1987

 

For detailed habitat information see WWF - National Geographic: WildWorld: Terrestrial ecoregions of the world. http://www.nationalgeographic.com/wildworld/terrestrial.html
 
 
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Lorises and pottos: species, subspecies, local populations
Last amendment: 14 November 2003

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