Quantifying land impacts of wind energy: a regional-scale assessment in Finland

Large-scale deployment of wind energy raises ecological concerns about land use changes. Here, we conducted a quantitative assessment of land impacts of 42 wind farms (513 turbines) from Ostrobothnia, Finland. Located on the Baltic Sea coast, Ostrobothnia is a strategic region for national wind energy targets. Our main objectives were (1) to calculate landscape metrics (e.g., habitat composition, loss and fragmentation) within wind farm project areas, (2) compare the amount of building-related deforestation between project areas and simulation-based control areas and (3) compute the overlap between project areas and regional land use plans. According to CORINE Land Cover datasets, the predominant habitats within project areas were forests (371.7 km(2); 81%) and transitional forests (52.7 km(2); 11%). The remaining 8% were agricultural areas (17.6 km(2); 4%), waters (12.5 km(2); 3%) and artificial surfaces (2.9 km(2); 1%). Wind farm infrastructure corresponded to 1.4-6.0% of project areas and caused similar degrees of habitat fragmentation. Deforestation levels in project areas were higher (similar to 6 times on average) than in control areas, and the micro-siting of turbines did not avoid mature forests by favouring e.g., transitional forests (which are ecologically less valuable). We found some spatial incongruence between project areas and regional land use plans, with 78 turbines falling outside the established boundaries. Our results highlight the need for careful ecological considerations in wind energy spatial planning in Finland (and countries with similar landscapes and land uses) to limit forest loss and its detrimental impacts on forest-dependent species, but also on carbon storage and sequestration.