ABSTRACT
In the past some scientists have emphasised the
role of climate as the dominant influence on
later Holocene erosion history, while others
have attributed greater influence to the role of
people. Today there is a growing recognition
of the complex interactions between factors,
leading to the advocacy of more sophisticated
multi-causal explanations (A.G. Brown, 1997;
Endfield, 1997; Macklin, 1999). Erosion is a uni-
versal geomorphological process. Under natural
conditions erosion rates are governed by such
factors as climate (especially precipitation levels
and distribution, as well as temperature range),
vegetation, slope angle and aspect, soil and
bedrock type. Erosion occurs particularly on un-
vegetated, or sparsely vegetated, slopes where soil
and sediment are exposed to subaerial weathering.
In those semi-arid or arid areas with less than
c.600 mm of rainfall (e.g. parts of the Mediter-
ranean, western United States and central Asia)
erosion rates will be closely related to the extent
of partial vegetation cover at particular times
(French, 2003). Even in those areas which had once
been fully vegetated, progressive Holocene clear-
ance and the creation of agricultural landscapes
have meant that anthropogenic factors became
increasingly important in determining the rate
and pattern of soil erosion. Many studies demon-
strate greater runoff and erosion with decreasing
vegetation cover (Lockwood, 1983). Data from
North America suggest that the river sediment load
doubles for every 20 per cent loss of forest cover.
On sandy soils in Bedfordshire, UK, for example,
