Soil erosion and climate change: the transect approach and the influence of scale

Studies of gee-ecological processes are being made along climatological transects on similar limestone rocks at different locations across the Mediterranean. The main objectives of the research are firstly, to gain insight into the influence of climate on key-geomorphological process-pattern relationships that characterise different locations along the transect; and secondly, to obtain a better insight into the possible impact of climate change on ecosystem degradation. The paper begins by considering the possible methodological approaches that can be applied to investigate the impact of climate change on ecosystem degradation in complex ecosystems and explains why a nonlinear evolutionary modelling framework was chosen for the transect studies, The conceptual basis of the methodology is presented and the transect approach described. The research methodology takes into account the influence of climate at four different scales (landscape, slope, response unit and patch). Field research at these scales is oriented towards identifying and understanding the key processes and to identifying key parameters that can be monitored to establish change. Some results are presented from the Judean Desert transect in Israel to show how a key indicator, in this case aggregate stability, varies with temperature and to show how process-pattern features vary along the Limestone transect from the area having a Mediterranean climate to the desert. Both conceptual and practical models of soil erosion need to address scale issues. In particular, as time and spatial scales change, so also does the relative significance of different processes. It is concluded that process-pattern phenomena are useful in this context and that they can be applied to the problem of up-scaling. (C) 1998 Elsevier Science B.V. All rights reserved.