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Polleniferous sediments from SE Asian lakes and swamps may reflect anthropogenic changes in their surroundings. Increases in the abundance of pollen of secondary forest trees, herbs and crop plants are possible indicators of human activity, as are evidence of soil erosion and presence of charcoal. The areas most studied so far are Sumatra and New Guinea. Sites in Sumatra show forest disturbances from 4000 BP or earlier: possibly 7000 BP. From about 2000 BP permanent clearings appear. In New Guinea there is forest clearance in the highlands from c. 5000 BP or earlier, disturbance of swamps back to c. 9000 BP, and evidence of burning from c. 10,000 BP. Man has been practising forest disturbance in SE Asia for thousands of years, and this has led to ecological degradation.

inputs vary, but still this is a common characteristic for most of the biomes about which we will be taking. When we come, however, to consider precipitation, it is a little more difficult, because regions with this high radiant energy input embrace areas ranging from those with plentiful rainfall and high humidity throughout the year to nearly rainless deserts and through many climates with complex gradations between these two extremes. When we consider the concept of 'the norm', therefore, we may well be forced to limit our definition to, say, a true core area, such as the genuine lowland tropical rain forest and Koppen's Af climates. The tropics are also a region in which chemical and biological changes are noted for their speed of reaction, and we shall have to see whether the speed and nature of these reactions differ by degree only or in fundamental principle from those obtaining elsewhere on the globe. And, finally, we must accept, initially at least, a traditional view of the lowland tropical rain forest belt, namely that it is very old and has been but little affected by the climatic and other environmental changes incident on the Quaternary glaciations. However, I suspect that Dr Flenley may have a few caveats to enter concerning that common view and we may have to consider anew the so-called stability of a core community of lowland tropical rain forest. Let us now consider the second word, that enigmatic concept of a 'norm'. The main thesis underlying the question mark of this meeting is that, perhaps, because so much biogeographical and ecological theory has been developed from work in the boreal and temperate regions of the world, this theory has turned what is essentially the abnormal?the simple and the geologically young?into the normal, and that it could be misleading to have developed most of our basic principles in regions with soils and vegetation which are, in the main, less than 10 000 years old. Should not the tropics be the norm for developing theory and basic principles and not these clearly juvenile and ill-developed areas? I shall quote, as an example of the dilemma, one extreme instance. If the wilder theories of certain writers, such as those of the Russian, Federov (1966), were proved to have substance, and speciation (the creation of new species) in lowland tropical rain forest was seen to be governed by the random processes of genetic drift and not the clearly adaptive neo-Darwinistic principles of natural selection, then there would be no obvious and essential ecological relationship between habitat and species. The fundamental tenet of most ecological thinking would, in fact, be brought into question. This extreme case illustrates well the problem which we are confronting. In this instance, the differences would not be of degree only, but of principle. Many workers, on the other hand, regard the differences as of degree rather than of principle. The

Late Quaternary pollen records are described from two swamps at c. 1500 m a.s.l. in the Sumatran Highlands. At Danau di Atas (DDA) the record extends back to c. 31,000 BP. At Telago (TEL) the record extends back to c. 9000 BP. The results suggest that, in the Late Pleistocene, vegetation zones were depressed, and a gymnospermrich rainforest, now found only above 1800 m, surrounded DDA. At times upper montane forest may have been close to the site, suggesting a vegetational depression of c. 800 m. Mean annual temperature may have been c. 1.6?C to c. 5.2?C cooler than now. There is no direct evidence of formerly drier climates, although a possible reduction of water levels in the Late Pleistocene is suggested. During the Holocene, there is evidence for disturbance of rainforests, possibly by man, from a date some time after c. 8200 BP. Extensive recent forest clearance is demonstrated.

We report the first collection of Isoetes from Sumatra. The material belongs to a new species. The discovery eliminates a previous biogeographical anomaly, the absence of the world-wide genus Isoetes from Sumatra.

There are at least three reasons for suspecting the vegetation of the New Guinea Highlands to be changing. Firstly, forest is being actively cut down by the New Guineans to make gardens and it has even been suggested (Robbins 1960) that almost all the non-forest (i.e. vegetation other than forest) is anthropogenic. Secondly, there is geomorphological evidence of a lower snowline formerly in New Guinea (Dozy 1937; Reiner 1960; Bik 1967) and the vegetation may therefore have been influenced by long-term climatic changes. Thirdly, New Guinea is subject to tectonic disturbance and volcanic activity (Taylor 1957), which may have had vegetational repercussions. Previous ecological work in the Highlands has been mostly restricted to general ecological surveys (e.g. Robbins 1958; Robbins & Pullen 1965) and to more detailed studies of small areas (Walker 1966, 1968). The present paper reports mainly random sampling of all vegetation within the Wabag region, including the 'montane' rain forest, and analysis of the data by computer techniques for classification and ordination. This contrasts with recent numerical analyses of rain forest (Ashton 1964; Webb et al. 1967a, b; Greig-Smith, Austin & Whitmore 1967) which have all been carried out on data collected from subjectively sited plots in lowland forest.