Plant resurvey of fine-scale species richness patterns in mountain tundra in northern Finland

Arctic tundra vegetation is responding to rapid climate change, including a progressive shrub expansion, increasing species richness, and upslope distribution shifts. Tundra vegetation patterns are significantly determined by fine-scale environmental conditions, particularly wintertime microclimates, such as soil temperature and snow cover, in addition to mesotopography, geomorphological processes, soil moisture, soil pH, and soil nutrients. Accordingly, vegetation shifts are expected to reflect local environmental gradients, and they may occur at fine scales over a shorter time frame. Yet the role of these factors in driving fine-scale changes and the timing remains insufficiently understood. Here, we aim to examine short-term vegetation shifts at fine scales, focusing on vascular plant species richness and its relationship to fine-scale environmental gradients. Species richness is essential to assess vegetation transitions, as it enhances ecosystem functioning. Vegetation data were resampled in the summer of 2024 and 2025 along fine-scale environmental gradients and latitudes, comprising a total of 378 plots. However, temporal trends in species occurrences were observed in several species, such as Pedicularis lapponica and Deschampsia flexuosa, on more than 40 plots during the 2011–2025 study period. Analysis of their species distributions is underway to assess whether significant spatial shifts in community composition occurred, albeit with stable species richness. Full results, including refined analysis of species richness-environment relationships, will be presented at the conference.