Looking back within the agricultural areas, we found two types of landcover change. The first is driven by expansion; the conversion of landcover to crops and pastures has continued on the fringes or the frontiers of the established cropping areas in all states examined. This expansion has been driven by market forces, particularly during the early part of the 1980s. I am convinced that much of this marginal land cleared for private gain will become a social and landcare burden on the public purse within a decade, if it isn't already.

Within the core areas, landcover change continued with vegetation remnants succumbing to the plough. This loss of even these fragmented remnants of natural ecosystems has significance for the relentless biotic impoverishment of the continent.

There was good news. We saw from the changing patterns of cropping that conservation of the soil resource has grown in importance and practice over the time that we looked back. It may be small, but it is an unmistakable start.

The landcover change we found in Australia was similar to that detected in Rondonia and Kansas. The changes and consequences are the same, even though the driving forces differ. The current landuses in both Rondonia and in Kansas appear unsustainable in the long term. Are they sustainable in Australia?

Expanding or intensifying agriculture is not without significant costs. Any rational society concerned about its long-term well-being would ensure that all those costs are weighed against the benefits.

The problem is that any society whose population continues to grow at a very high rate, such as ours, has already foreclosed many of its options. Such a society must expand or intensify agriculture at the expense of all else.

If we scale importance according to the size of the area involved, Australia is still a Pastoral nation. Pastoralism, the most extensive landuse in Australia, is still changing the landcover of the rangelands.

In The Old areas of pastoral landuse, the mismanagement of landcover was localised rather than widespread. In The Desperate areas, the landcover changes we found can be interpreted as the last management option. In contrast, the extraordinary landcover dynamics found in The New and The Marginal present a challenge to this society. This dramatic capacity of Pastoral landuse to change the face of the continent should, like all powerful influences in a democratic society, be closely scrutinised.