Conclusions
In this study, ruderal species composition and distributions along the Rallarvägen showed to be mostly related to the original disturbance event since its inception at the start of the 20thcentury, as well as to continuous gradients in disturbance intensity, while recent climate change effects were not (yet) significant. Different parts of our investigation support this conclusion: 1) the number of ruderal species that has remained stable over time and the higher influx of non-native ruderals during railroad building back in 1903 and settlement expansion in 1913, 2) the lower EIV-T-values of recent ruderal observations, 3) the higher abundance of ruderals closer to the railroad and train stations in 2021, and 4) the upward migration of ruderals that was not related to the species’ climatic constraints, but rather (positively) to their first year of observation. Most importantly, these findings demonstrate that historic disturbances, not climate change, have resulted in an influx of warm-adapted species into this subarctic region. We therefore conclude that these findings warrant for discretion when we make conclusions about the exact impacts of climate change to ecosystems, especially when historic disturbances have been present. Such significant disturbance events can have long-lasting effects on vegetation compositions and distributions and therefore overrule climatic factors as drivers of species distributions (Lenoir et al. 2022). Most importantly, our results highlight the importance of the knowledge of disturbance history of a system when interpreting species distributions. Nevertheless, the rapid changes in climate observed in the Abisko region suggest that we will likely see the fingerprints of climate change effects on the vegetation communities in the future.