Connectivity in Agricultural Landscapes; do we Need More than a Dem?

DEM's at a scale of metres to kilometres form the basis for many erosion models in part because data have long been available and published by national mapping agencies, such as the UK Ordnance Survey, and also because modelling gradient and flow pathways relative to topography is often simply executed within a GIS. That most landscape connectivity is not driven by topography is a simple issue that modellers appear reluctant to accept, or too challenging to model, yet there is an urgent need to rethink how landscapes function and what drives connectivity laterally and longitudinally at different spatial and temporal scales within agricultural landscapes. Landscape connectivity is driven by a combination of natural and anthropogenic factors that can enhance, reduce or eliminate connectivity at different timescales. In this paper we explore the use of a range of data sources that can be used to build a detailed picture of landscape connectivity at different scales. From a number of case studies we combine the use of maps, lidar data, field mapping, lake and floodplain coring fingerprinting and process monitoring to identify lateral and longitudinal connectivity and the way in which these have changed through time.