Monday, 29 March 2004

We are delighted to welcome Professor Robert Hall to address the Royal Geographical Society on the world's great biogeographical divide Wallace's Line.

Wallace's Line, which bisects the Indonesian Archipelago, marks the world's key ecological barrier, separating the Asian, and the rest of the world's, faunas and floras to the north and west, from those of the Australasian biosphere to the south and east. The animals and plants of SouthEast Asia are quite different on either side of this narrow zone. To the west and north, there are animals ranging from tigers to orangutans, while to the east and south there are kangaroos and koalas.

This line was first mapped and described by the great naturalist and evolutionary theorist Alfred Russell Wallace in the mid 19th century. This feature was a key piece of evidence that led Wallace to develop, alongside Charles Darwin, a robust theory of biological evolution. While researching in SouthEast Asia, Wallace was particularly impressed by the sudden difference in bird families he encountered when he sailed just twenty miles east of the island of Bali and landed on Lombok. On Bali, the birds were clearly related to those of the larger islands of Java and Sumatra, and indeed the rest of the world. On Lombok, the birds were clearly related to those of New Guinea and Australia. Through the study of a range of flora and fauna, he marked the line between Bali and Lombok and right through the islands of the Indonesian archipelago as the divide between world's two great biogeographical regions, the Oriental and Australasian.

In this lecture, Professor Robert hall revisits Wallace's Line and explains, with the aid of complex computer animation, how the motion and collision of the Australian and Asian tectonic plates over the recent geological past has been responsible for the separate floras and faunas developing.

Professor Robert Hall is Professor of Geology at Royal Holloway University of London and Director of its SouthEast Asia research group. He received his doctorate in 1974 on ophiolites and sutures in the Middle East and since 1984 has specialised in SouthEast Asia. He has led numerous expeditions to the region and is a world expert on the collision zone tectonics and the tectonic evolution of the SouthEast Asia and SouthWest Pacific Region.

Members and their guests are most welcome to attend this lecture, which is HK$50 for Members, HK$100 for Members' guests and HK$150 for others.