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DEFORESTATION
When people change the land
By observing land-cover changes via remote sensing, one can study how the use of land influences land cover. Empirical, diagnostic models of land-use/cover change developed from such observations can then be used as a vital tool in sustainable regional land management.

Start in a small way

However, broad-scale, fast-track approaches to land-use change are apt to produce superficial results. To really grasp the complexity of land-use changes, small-scale land cover and socio-economic data are needed. Because collecting such data globally is a daunting task, one must focus attention on a sampling of areas to collect remote sensing and field observations. The generic trajectories and processes of change identified over these selected regions can then be carefully generalised for larger areas.


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Study the field

These selected regions must of course be truly representative, and sufficient knowledge of social and ecological processes leading to land-use changes must be available. That's why collaboration between remote sensing specialists and human ecologists conducting long-term, field-based land-use studies is so highly productive. Remote sensing scientists identify patterns of land-use changes and, using geographic information systems (GIS), relate observed patterns of change to natural and cultural landscape characteristics. Human ecologists have a deeper insight into the processes of change and the complexity of the driving forces impelling a particular land use. However, in contrast to remote sensing and GIS approaches, field-based studies rarely yield a good overview of the exact extent of land-use change processes.


Map of the areas studied

 

And add remote sensing

The remote sensing component is then added to the collection of African study sites where long-term, field-based studies of land-use change are being conducted. For most of these sites, a collaboration was established with leading anthropologists.

Such analysis of landscape dynamics generates spatial statistical models of land-cover change, which can be used to:

  • Test hypotheses about change processes and their driving forces over an entire region;
  • Suggest issues that need more investigation via field work;
  • Pinpoint project areas at risk of being affected by land-cover conversion or modification in the future;
  • Evaluate the likely impacts of such transformations.

The last two points are particularly important for land use planners. They not only need to measure the rates and identify the factors of land-cover changes, but also anticipate where changes are likely to occur.