Effects of historical land-use change on species richness and community composition in fragmented and newly created habitats (HiLUCC)

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Historical land-use change may have considerable influence on current ecosystem composition, structure and function. Past local land use can have persistent legacy effects on communities, e.g. through alterations of site conditions, soil seed banks or persisting species. At landscape scale, land-use change may drastically alter the spatial configuration of habitats, such as patch size and overall amount and connectivity of the respective habitat type in the landscape. Habitat configuration is known to affect assembly and diversity of communities. Thus, in cases where habitat configuration changed substantially due to land-use change, the historical habitat configuration may have a significant influence on current communities.We will use data on plants and arthropods from the Experimental Plots (EP) in grasslands together with land use/ land cover maps from 1870-2010 (to be completed in this project) of all three Exploratories to model the effects of past land use and historical habitat configuration on species richness and community trait composition. The land use/ land cover maps as well as landscape metrics derived from these maps will be made available to all participants of the Biodiversity Exploratories through BExIS to support further studies on effects of historical land-use change on, e.g., ecosystem functions and services.Thus, the objectives of this project are: 1.) Historical land-use and landscape analysis: we will digitise land use/ land cover from historical maps, analyse land-use trajectories at local and landscape scale, and calculate landscape metrics to quantify historical landscape structure in the Schorheide-Chorin and Schwäbische Alb Exploratories. This has already been completed for Hainich-Dün in a preliminary study. 2.) Modelling the effects of historical landscape dynamics on species richness of plants and arthropods: here, we will test the hypotheses that historical habitat configuration affects current species richness and that it is more important than the current configuration if there was a marked change of grasslands (increase, decrease). Further, we will specifically analyse cases of habitat creation and expansion (e.g. in Hainich-Dün), and fragmentation, the latter including modelling of possible extinction debt. 3.) Modelling effects of past land use and historical habitat configuration on trait composition of communities: under this objective, we will model historical effects on multivariate trait composition, proportion of certain species groups (e.g. habitat specialists) and on community (weighted) means of traits. 4.) Quantitative modelling of interactions between species traits and effects of past land use and historical habitat configuration: for this purpose, we will use a new modelling approach based on Generalized Linear Mixed Models to quantify how much certain traits modify the relationships of species occurrence to past land use and historical habitat configuration.