We simulated three scenarios for investigating future metapopulation selleck compound structure and extinction risk of N. pennata. First, we simulated two scenarios that assumed rates of metapopulation and tree fall dynamics according to the empirical data from the period 2001 to 2008 (1997/1998–2006 for abundance). The rate of tree fall was found to be much higher after than prior to 2006, so we investigated an additional scenario that assumed tree fall rates according to the empirical data from the period 2006–2008. We simulated 30 time steps (years). All simulations were started at the conditions prevailing in 2001 at our 3–4 ha study site (Fig. 1) in terms of number of host trees (patches), d.b.h. and N. pennata occurrence. The size of the study site is typical of woodland key habitats that are delineated for the conservation of red-listed species and biodiversity in Sweden (Hansson 2001). Moreover, an overlay analysis of N. pennata observations reported to the Swedish Species Gateway together with woodland key habitats on private land using a GIS revealed that the median size of key habitats hosting N. pennata is 3·4 ha. For each time step, we simulated tree fall, d.b.h. growth and recruitment of new (randomly located) host trees in the order described. Next, local population and metapopulation dynamics were simulated: abundance growth on occupied trees, colonization of unoccupied trees, and extinction of extant local populations. Two types of local extinctions occurred: stochastic extinctions from occupied trees and deterministic extinctions as occupied trees fell. The models used for the simulations are described in detail in Appendix S1 (Supporting information). For each scenario, we ran 700 replicates using 700 draws from the posterior distribution of the parameters of the separate Bayesian models. Scenario 1 (S1). The first scenario assumed interior forest conditions and rate of tree fall as observed during the whole study period: The simulation models for rate of tree fall and relative abundance growth were based on data recorded ≥100 m from the clearcut edge. Scenario 2 (S2). In this scenario, edge conditions were assumed to prevail throughout the forest patch regarding rate of tree fall and relative abundance growth. Specifically, the models for rate of tree fall and relative abundance growth were based on data recorded <100 m from the clearcut edge. Scenario 3 (S3). S3 also assumed edge conditions, but differed from S2 in assuming a rate of tree fall corresponding to the higher rate observed after 2006. This tree fall rate is assumed to reflect the conditions that prevailed after ash dieback had spread in the study region.