Dataset associated with: Increasing presence of non-native plants and arbuscular mycorrhizal fungi during a 10-year survey along subarctic mountains roads

Roads in cold climate mountains are known to be important vectors in the introduction and spread of non-native plant species. In the same context, mycorrhizal fungi communities are also altered by roads with a known positive effect on arbuscular mycorrhizal (AM) fungi diversity and abundance in disturbed roadsides. However, to what degree these two effects of roads are intertwined and how they are evolving over time is not well understood. In this study we conducted repeated surveys of non-native plants and AM fungi between 2012 and 2022, in the northern Scandes mountains to investigate temporal changes and interactions between roads, mycorrhizal fungi, and non-native plants. We found that the upward spread of non-native plants and lateral spread away from the roadside into the natural vegetation were so far extremely limited, with only two out of 23 non-native species showing an increase in their upper elevational limit. However, non-native plant species cover did increase over the ten year period, especially at lower elevations, and non-native richness increased from 17 to 23 species. Likewise, we saw an increase in AM fungal abundance over the last four years along the roadsides at lower elevations. Furthermore, our results suggest that increases in non-native species are unlikely to be the driving cause of the observed increase in AM fungal abundance, as AM fungi colonization varied independently of non-native species cover dynamics. This is the associated datasets and R-code. Check out the ReadMe.txt-file for information on the different files.寒冷气候山地中的道路，被证实为外来植物物种引入与扩散的重要媒介。在此背景下，道路同样会改变菌根真菌（mycorrhizal fungi）群落结构，且已知其对受干扰路边的丛枝菌根（arbuscular mycorrhizal, AM）真菌的多样性与丰度具有积极影响。然而，道路的这两种影响以何种程度相互交织，且随时间推移如何演变，目前仍未得到充分阐明。本研究于2012年至2022年间，在北斯堪的纳维亚山地开展了针对外来植物与丛枝菌根真菌的重复调查，以探究道路、菌根真菌与外来植物之间的时间动态变化及相互作用。研究结果显示，外来植物的向上扩散以及从道路侧向延伸至自然植被的扩散范围迄今仍极为有限：23种外来植物中仅2种的最高海拔分布上限出现上升。不过，十年间外来植物的盖度确实有所提升，尤其在低海拔区域；同时外来植物的物种丰富度从17种增至23种。同样，过去四年间低海拔区域路边的丛枝菌根真菌丰度也出现了上升。此外，本研究结果表明，外来植物物种的增加并非观测到的丛枝菌根真菌丰度上升的驱动因素，因为丛枝菌根真菌的定殖情况与外来植物盖度的动态变化相互独立。本研究附带相关数据集与R语言代码。请查阅ReadMe.txt文件，以了解各文件的具体信息。