Sticking to the trail: Seed rain, seed bank and seedling density are elevated along hiking trails in the Scandes mountains

Aims Plant species' distribution ranges are expected to shift towards previously uncolonized locations in response to climate warming. Mountain trails, which often access to areas of special ecological value as well as remote and climatically extreme locations, could influence such shifts through changes in dispersal and disturbance. Trails may facilitate the dispersal of propagules to new locations, influence the seed bank by changing propagule input and persistence and change establishment success through the creation of gaps and disruption of biotic interactions. However, knowledge regarding the influence of mountain trails on seed rain, seed bank abundance and seedling emergence in alpine ecosystems is lacking. In this study, we examine the influence of hiking trails on dispersal patterns in mountain ecosystems. Location Dovrefjell, Scandes mountains, Norway. Methods We surveyed seed rain, seed bank abundance and seedling emergence along four hiking trails spanning climate gradients with a mean 2.5 degrees C difference between warmest and coldest location at four elevations per trail and at 0.5, 7 and 17 m from the trail (48 plots, in 16 transects). Results Seed rain was 3.4 times higher in trailside plots than in those 17 m away and declined with colder climate at all distances from trails. Seed bank abundance on trailsides at the warmest location was eight times higher than in plots at 17 m distance, while there was no significant difference at colder locations. Seedling establishment was disturbance-driven along the whole climate gradient, with 3.5 times more seedlings on trailsides than at 17 m distance. Conclusion Mountain trails have the potential to facilitate vegetation shifts by capturing more seed rain and creating opportunities for seedling establishment. Our findings highlight the importance of including trail effects in studies of vegetation shifts.

Automated summary

The study showed that mountain hiking trails have significant influence on seed rain, seed bank abundance, and seedling emergence, facilitating vegetation shifts. Plots near trails had higher seed rain and seedling abundance, indicating a positive role of trails in plant dispersal and establishment.