title: Gross changes in reconstructions of historic land cover/use for Europe between 1900 and 2010.
abstract: Historic land-cover/use change is important for studies on climate change, soil carbon, and biodiversity assessments. Available reconstructions focus on the net area difference between two time steps (net changes) instead of accounting for all area gains and losses (gross changes). This leads to a serious underestimation of land-cover/use dynamics with impacts on the biogeochemical and environmental assessments based on these reconstructions. In this study, we quantified to what extent land-cover/use reconstructions underestimate land-cover/use changes in Europe for the 1900-2010 period by accounting for net changes only. We empirically analyzed available historic land-change data, quantified their uncertainty, corrected for spatial-temporal effects and identified underlying processes causing differences between gross and net changes. Gross changes varied for different land classes (largest for forest and grassland) and led to two to four times the amount of net changes. We applied the empirical results of gross change quantities in a spatially explicit reconstruction of historic land change to reconstruct gross changes for the EU27 plus Switzerland at 1 km spatial resolution between 1950 and 2010. In addition, the reconstruction was extended back to 1900 to explore the effects of accounting for gross changes on longer time scales. We created a land-change reconstruction that only accounted for net changes for comparison. Our two model outputs were compared with five commonly used global reconstructions for the same period and area. In our reconstruction, gross changes led in total to a 56% area change (ca. 0.5% yr(-1)) between 1900 and 2010 and cover twice the area of net changes. All global reconstructions used for comparison estimated fewer changes than our gross change reconstruction. Main land-change processes were cropland/grassland dynamics and afforestation, and also deforestation and urbanization.
authors.affiliation: Laboratory of Geoinformation Science and Remote Sensing, Wageningen University, Wageningen, The Netherlands.
authors.forename: Richard
authors.initials: R
authors.lastname: Fuchs
authors.forename: Martin
authors.initials: M
authors.lastname: Herold
authors.forename: Peter H
authors.initials: PH
authors.lastname: Verburg
authors.forename: Jan G P W
authors.initials: JG
authors.lastname: Clevers
authors.forename: Jonas
authors.initials: J
authors.lastname: Eberle
mesh_terms: D000383:Agriculture / Q000266:history*; D044822:Biodiversity; D057231:Climate Change; D003247:Conservation of Natural Resources / Q000706:statistics & numerical data* / Q000639:trends; D017753:Ecosystem; D005060:Europe; D062305:Geographic Mapping; D065948:Grassland; D049673:History, 20th Century; D049674:History, 21st Century; D007221:Industry / Q000266:history
keywords: assessment; back casting; climate; greenhouse gas; historic ecology; historic land dynamic assessment; land cover; land use; land-use history