LANDSCAPE SENSITIVITY IN TIME AND SPACE - AN INTRODUCTION

Abstract

Landscape sensitivity may be discussed in terms of the response of landscape systems to perturbation on different time and spatial scales. Unstable systems behave chaotically but may show self organised criticality, while stable systems resist change until threshold values of system parameters are exceeded. Spatial sensitivity is expressed in different rates of change, between landscape components or elements. This leads to divergence between landscape elements, and the inheritance of palaeoforms in present-day landscape mosaics. Temporal sensitivity reflects the magnitude and frequency of individual events nested within patterns of longer term environmental changes occurring on different timescales. The resulting landscape complexity reflects the spatio-temporal sensitivity of earth surface systems over ten orders of scale magnitude. The connectivity within landscapes ensures that site instabilities can be propagated within multievent feedback systems. Landscapes record their own histories in sediments and soils, but interpretation of event stratigraphy may not be straightforward, while soil profiles can absorb individual events without erosion. Although we are increasingly able to model the present, environmental management is dominantly about conserving inherited properties of landscapes: forests, soils, floodplains, coastlines. Landscape sensitivity for landscape management must, therefore, address not only active, largely nonlinear, environmental systems, but also the mosaics and palimpsests that are the inheritance from past environments.