Analysing land cover change using time series analysis of Landsat data and geoinformation processing: a natural experiment in Northern Greece

Land use conversions or changes of land management practices are primary drivers of global environmental change. 'Natural experiment' situations, where some conditions vary, but other potential land use determinants remain relatively constant, offer unique opportunities to study land use change, its drivers and feedbacks on human-environment systems. The Chalkidiki peninsula in Northern Greece is an ideal test case to study recent land use transformations and socio-economic changes (e.g. resulting from accession to the EU) against a stable reference area. Of the three peninsular legs of Cassandra, Sithonia and Athos, the latter harbours the 'Autonomous Monastic State of the Holy Mountain', a sovereign and isolated monastic state. Apart from subsistence agriculture around the monasteries, it represents a Mediterranean ecosystem in a state virtually unaffected by modern human use. We have used a time series of 22 fully corrected Landsat-TM and ETM+ data to study land use/land cover change on the peninsula, and related the results to a similar study in the adjacent County of Lagadas. A diachronic land use change analysis based on SVM classification was conducted using two three image-pairs. Where natural and semi-natural vegetation formations remained stable, trends were calculated using a pixel-wise linear trend analysis of SMA-derived vegetation cover estimates. Results were interpreted using auxiliary data and in relation to the Athos area. Changes were found to result from discontinuation of extensive land use in Cassandra and Sithonia in favour of intensified agricultural use and the expansion of tourist activities, complemented by land abandonment in less attractive areas.