Assessment of the visual impact of marble quarry expansion (1984–2000) on the landscape of Thasos island, NE Greece

Marble extraction is an economically important and widespread activity in Greece that exists since historical times. The extraction takes place by open-pit quarries in hill slopes. The original landform is permanently altered and the original vegetation cover is destroyed. The visual impact of the quarries extends over larger areas as noticeable scars of high colour contrast, reducing the aesthetic appeal of the landscape and deteriorating the scenic quality of areas where tourism often is a major constituent of income. The aim of this work was to assess the ecological, landscape and visual impacts of marble quarries on the island of Thasos, NE Greece by employing remote sensing, geographical analysis and landscape metrics. Change detection and object-based classification were used to monitor the landscape dynamics (1984–2000) of marble quarries. A new index was defined to estimate the ‘cumulative visibility load’ on the landscape. An expansion trend of marble quarries was identified by the creation of new and the enlargement of existing quarries in the NE part of the island on areas previously covered by semi-natural pine forest. The visual impact increased by a factor of 2.52 and although the area of quarries was less than 1% of the landscape in 2000, it affected 13.5% of the island, including areas such as the islandʹs capital and nearby coasts.