The roles of agriculture and climate in land degradation in southeast Iceland AD 1700–1900.

Past human land-use is increasingly recognized as a driver of ecosystem change in seemingly natural landscapes. Quantification of historical land use is therefore critical for assessing the degree of human impact and requires integration of geography, ecology and history. This paper examines the impact of climate change, land-use and exposure to international markets on the terrestrial ecology in Suðursveit, in southeast Iceland between AD 1700 and 1901. For this we use historical data concerning land-use, livestock and demography, and mapping of glacier advance, glacier outburst floods (jökulhlaups) and agricultural land. Change in land-use or population during the eighteenth century was insignificant. Population declined in the first two decades of the nineteenth century due to the advance of Breiðamerkurjökull glacier. After AD 1820, Suðursveit became part of international market for agricultural products, which facilitated population and livestock increase. This led to overgrazing and severe land degradation in the nineteenth century. [ABSTRACT FROM AUTHOR]