Changes in forest landscape patterns resulting from recent afforestation in Europe (1990-2012): Defragmentation of pre-existing forest versus new patch proliferation.
The present dataset was construct with the aim of addressing the association between forests cover increase and spatial pattern change in the European landscapes, while considering the landscape land cover composition and the altitudinal and geographical gradients. We hypothesized that forest increase is determining (i) a decrease in the overall landscape diversity, (ii) a forest defragmentation and (iii) an increase in forest connectivity across Europe. We used the recent set of medium- to high-resolution land use and cover (LC) maps worldwide available: those of the Climate Change Initiative (CCI) by the European Spatial Agency (ESA 2017), and the forest cover change maps of the Global Land Cover Facility (GLCF) from the University of Maryland(Hansen et al. 2013; Kim et al. 2014). Using LC maps we randomly selected 752 landscapes 5-km radius across Europe with recent (1990-2012) forest increase and we calculate for each landscape for the years 1990 and 2012 the following landscape metrics: forest patch number (n), mean and largest forest patch size (ha), total forest edge (m), forest effective mesh size (ha), percentage of forest like adjacencies (%), Euclidean nearest neighbour distance and Shannon diversity index. In order to assess the modulating role of environmental context on the association between forest increase and landscape change, we included a set of variables regarding geographical position, topography, and initial composition of the study landscapes: Percentage of each land cover in 1990 (%), longitude (º), latitude (º), average of slope in the plot (º), average of elevation in the plot (m), mean annual temperature between 1970-2000 (ºC), standard deviation of annual temperature between 1970-2000 (ºC), Annual precipitation between 1970-2000 (ºC) and Annual precipitation standard deviation between 1970-2000 (ºC). Finally we performed a set of GLM on randomly selected 752 landscapes with recent (1990-2012) forest increase to assess the modulating role of environmental context on the association between forest increase and landscape change. Results showed that the decrease in landscape diversity in the last decades was not associated to forest increase but to high cropland and low scrub-grassland cover. Forest increase promoted the defragmentation of already existing forests and new patch proliferation in forest-dominated and non-dominated landscapes, respectively. These processes also depend on elevation and geographical position, with forest defragmentation concentrated in Northern and Eastern Europe and new patch proliferation in southern and western regions, and in mid-elevation areas.