We have compiled 223 sedimentary charcoal records from Australasia in order to examine the temporal and spatial variability of fire regimes during the Late Quaternary. While some of these records cover more than a full glacial cycle, here we focus on the last 70,000 years when the number of individual records in the compilation allows more robust conclusions. On orbital time scales, fire in Australasia predominantly reflects climate, with colder periods characterized by less and warmer intervals by more biomass burning. The composite record for the region also shows considerable millennial-scale variability during the last glacial interval (73.5e14.7 ka). Within the limits of the dating uncertainties of individual records, the variability shown by the composite charcoal record is more similar to the form, number and timing of DansgaardeOeschger cycles as observed in Greenland ice cores than to the variability expressed in the Antarctic ice-core record. The composite charcoal record suggests increased biomass burning in the Australasian region during Greenland Interstadials and reduced burning during Greenland Stadials. Millennial-scale variability is characteristic of the composite record of the subtropical high pressure belt during the past 21 ka, but the tropics show a somewhat simpler pattern of variability with major peaks in biomass burning around 15 ka and 8 ka. There is no distinct change in fire regime corresponding to the arrival of humans in Australia at 50 AE 10 ka and no correlation between archaeological evidence of increased human activity during the past 40 ka and the history of biomass burning. However, changes in biomass burning in the last 200 years may have been exacerbated or influenced by humans.

Aim This paper documents reconstructions of the vegetation patterns in Australia, Southeast Asia and the Pacific (SEAPAC region) in the midHolocene and at the last glacial maximum (LGM).

This paper begins to identify the relative roles of climiiate change, people and fire as factors in the late-Pleistocene and Holocene evolution of one of the most diverse terrestrial ecosystems in southern Australia. Our research illustrates that pollen from mediterranean-type heathlands can be recogniized fromii sediments taken from small basins in semi-arid ecosystems. The use of pollen and carbonized particle analyses from sedimenit : :: cores, in conjunction with ecological research on planit-fire relationships, establishes a role for palaeoecological techniques in the interpretationi of long-term processes in semi-arid heathlands in Australia. Radiocarboni dates indicate that the treeless structure at our study site in the Little Desert of western Victoria has existed since at least the early Holocene. Pollen evidenice indicates an increase in plant diversity, especially in Proteaceae HOLOCEN and fire ephemerals, and a decrease in fir-e-sensitive taxa (e.g.. Callitris spp., Allocastutrina nii,elleriatna type) HOLOC NE usoer the last 4000 vears. This decline ocCtLirs in conjunction with increases in the frequency of carbonized SPECIAL ISSUE particles.

/ Preliminary analysis of pollen in three shallow sediment cores demonstrates that pollen is preserved in the seasonally dry, vertically accreting Barmah-Millewa Forest floodplain of the Murray River, SE Australia. Deposition characteristics of a floodplain are a critical component of catchment sediment budgets, but it has proven difficult to identify this important stratigraphic point in floodplains using radionuclide dating techniques. Pollen in a floodplain, as opposed to that preserved in lacustrine settings, provides opportunities for investigating the impact of European land-use on both sediment deposition and floodplain vegetation. Pollen from exotic plant taxa identified in floodplain sediments provided a chronostratigraphic marker for the boundary between pre- and post-European sediments in the Murray River floodplain. A maximum deposition rate of about 80 mm per 100 years is estimated from the sediment history. The pollen record shows vegetation changes within the forest since European settlement. These included changes in the density of the Eucalyptus forest; and in the composition of understorey herbs, sedges, and grasslands. Pollen concentration and charcoal and organic content also exhibit post-European changes. Thus, pollen analysis provides a technique for determining changes in sediment budgets and identifying major vegetation changes in floodplains.KEY WORDS: Pollen; Floodplain; Vegetation; Deposition; Budget; Sediment; Australia; Firehttp://link.springer-ny.com/link/service/journals/00267/bibs/24n3p359.html

European settlement has led to increased loads of fine suspended sediment (SS) entering the River Murray, Australia's largest, and arguably, most important river. The River Murray's anthropogenic sediment history can be divided into four periods with varying source areas, sediment loads, and seasonal patterns. The Aboriginal period (before 1840) was characterized by clear water at summer low-flows in the River Murray and its southern tributaries, with more sediment coming from the northern catchment than the southern, and the Darling River being turbid at all flows. There is little evidence that Aboriginal burning resulted in any measurable increase in SS. SS loads peaked in the 1870s and 1880s (the gold and gully period, 1850-1930) as valley floors were incised by gullies (mostly in northern tributaries), and gold sluicing flushed huge amounts of sludge into southern tributaries. Sedimentation in wetlands and on floodplains increased by 2-10 times in this period, and the biota in wetlands switched from clear water to turbid water communities.In the hiatus period sediment supply from gullies and gold mining waned and low flow SS concentrations returned to low levels. Dam construction through the 1960s and 1970s (the regulation period, 1960 on) disconnected the River Murray from catchment derived sediment. Despite this, SS levels increased again: now largely derived from instream sources including bank erosion from long duration summer irrigation flows, the spread of bottom-feeding carp (Cyprinus carpio), and wave erosion from boats. Erosion switched from winter to summer dominated. Significant investment in securing water for the environment in the Murray-Darling Basin could be complemented by addressing inchannel sediment sources in the River Murray itself to reduce turbidity. Overall, European era SS concentrations remain relatively low with small sediment delivery to the ocean (0.1Mt per annum), despite high catchment erosion rates. This is due to poor sediment delivery efficiency through the low-gradient landscape.