Impacts of Aeolian dust deposition on European forest sustainability: A review

Keeping European temperate forests on acidic soils sustainable is challenging for forest management and wood production. Nutrient budgets are a diagnostic tool that assesses forest sustainability by adding up nutrient inputs (atmospheric dissolved deposition and soil weathering) and outputs (losses in drainage water and by wood harvesting). In these forests, nutrient budgets of essential nutrients are often unbalanced, especially for the base cations Ca, Mg and K, meaning that these nutrients deplete from the ecosystem, what threatens forest sustainability. Whereas Aeolian dust deposition (ADD) is recognized as a significant nutrient input in various ecosystems, particularly in oceans, it is not taken into account in usual nutrient budgets of European forests. ADD has been characterized in different places in the world, however, little is known in European forests and about ADD impacts on their biogeochemical cycles. To fill this gap, this review aims at (i) synthesizing data on ADD characteristics in European forests to put forward a deposition model over Europe and calculate nutrient fluxes, (ii) highlighting the contribution of ADD to plant tissues in two ecosystems with an isotopic approach, (iii) evaluating the contribution of ADD to the total nutrient inputs, and (iv) assessing the impacts of ADD on European nutrient budgets of forests concerning Ca, Mg and K. Aeolian dust in Europe is either long-distance transported from arid regions such as Sahara or short-distance from the erosion of local soils. It was estimated to deposit between 41 and 129kgha⁻¹year⁻¹ throughout Europe. Its mineralogical composition reveals nutrient bearing minerals, silicates and nonsilicates (carbonates, oxides, hydroxides, sulphates, phosphates, halides). This suggests Aeolian dust may contribute as high as 30% of total nutrient inputs, so that it may significantly shift upwards nutrient budgets of European forests under latitude 52°N. Further investigations are therefore needed to inform about accurate ADD rates below the tree canopy and to take account of the total nutrient inputs.