Fig. 1: Simulated predictions of population responses of globally and locally adapted species to local climatic anomalies in relation to population niche position.

a shows a random subset of the study sites across the three countries (dots representing sites coloured and shaped by country: yellow circles - Spain, magenta triangles—UK, and black squared—Finland) representing a hypothetical species distribution for one thermal generalist species with populations with populations spanning the bioclimatic niche (see Methods) from the leading edge (niche position = −1) to the trailing margin (niche position = 1). The background colour of the map reflects mean annual temperature across the study period (with brown showing warmer conditions). b shows predicted responses to local climatic anomalies for populations spread across the full bioclimatic niche space for species that are either globally or locally adapted, with warmer sites shown in deeper brown colours. The local response in panel b shows performance (i.e., population change) in response to increasing anomalies (low to high) at each site (derived from a model fit simulating expected population growth in relation to the interaction between bioclimatic niche position and local climatic anomaly). The simulation code is available at [https://doi.org/10.5281/zenodo.15065537].