Land use/cover change analysis in the Mediterranean region: a regional case study of forest evolution in Castelló (Spain) over 50 years

The second half of the 20th century has been characterised by the rural abandonment in several regions of the Mediterranean basin. The general collapse of traditional agriculture and livestock activities brought about an intensive migration movement from inland to coastal areas, which produced a massive forest cover increase in abandoned rural areas. This socioeconomic, spatial and environmental change has led to a situation unknown for centuries in the Mediterranean landscapes. As a consequence, large wildfires have increased enormously in importance in a society with a predominant urban vision over the rest of the territory. Indeed, public opinion considers wildfires as major natural disturbances related to climate change causing at the end deforestation, while its prerequisite, a substantial increase of forest cover due to rural collapse, is less known. This research aimed to deepen the knowledge about forest evolution and its implications after the land abandonment process that started in the second half of the 20th century. The substantive source of information was obtained from a photointerpretation by sampling, using five general land-cover and land-use types and four specific land-cover types over a period of 50 years (1957–2007) in the province of Castelló (Valencian Region, Spain). Results showed that the area dominated by dense forests (shrublands and woodlands) has increased from 17% to 28%, and the area dominated by their transitional land uses after farming abandonment has increased from 8% to 21%. Transition matrices enabled a precise identification of changes among dominant categories over the studied period. Random and systematic transitions between categories have been analysed and a map of forest evolution pathways could be drawn, in which a double alternative path was identified. In the general context of progressive evolution to dense forests in the Mediterranean region, we have also found different evolution rates which may depend on site conditions. Their specific soil and climatic factors should be further analysed in order to improve our understanding of future forest evolution in the Mediterranean region at a local scale. A robust knowledge of these processes will contribute to improve forest management and land-use planning while optimising resilience, carbon storage and the provision of environmental services.