Clusters and environmental variablesOur results showed that species clusters differed in terms of the environmental variables analyzed. Generally, temperature-related variables (BIO1, BIO3, BIO4 and BIO9) were the main factors responsible for the differentiation between clusters. Elevation and terrain sculpting variables (WI, TI, TRI, and MRVBF) were among the most important topographic variables separating species groups. The influence of geological variables (related to bedrock) was relatively weak, but significant in some cases. It seems to us that the clusters analyzed can be divided into large groups reflecting their distribution and their characteristics derived from environmental variables. In case of climatic variables, the groups of Luzula arcuata and Carex rupestris can be considered the most cold tolerant, while the remaining groups seem to prefer areas with moderate (e.g. Anthoxanthum odoratum) and mild climatic conditions (Puccinellia maritima, Rumex longifolius). This differentiation appears to be primarily shaped by average temperature. There is, however, another interesting example of climatic differentiation present in the analyzed data set. This is the Saxifraga aizoides cluster, separated by a variable intended to quantify the seasonality of temperatures (coefficient of variation calculated from monthly averages). The values ​​of this variable were lowest in the case of the Saxifraga aizoides group, suggesting a better fit to areas with the lowest temperature oscillations during the year. It is clear that the relative frequency of Arctic species also followed the temperature gradient: being highest in Luzula arcuata, Carex rupestris and Bistorta vivipara and intermediate or low in the remaining groups apart from Puccinellia mariti...... middle paper......particularly important in terms of climate change and its effects on plant distribution. It seems that the spatial configurations of groups dominated by arctic species (Luzula arcuata, Carex rupestris) are more threatened than those comprising a significant proportion of boreal and temperate species. Callaghan et al. (2004) highlighted that Arctic species will be the most vulnerable to climate change. They argued that the ecological range of Arctic taxa will decrease and their abundance will decline with global warming. Currently, there is no correspondence between the distribution of protected areas and the distribution of groups with the highest proportion of threatened species. Proposals were made in 2008 to create several protected areas, but they have still not passed through the legislative process. It therefore seems that the mechanisms are still not in place to ensure effective protection of Icelandic flora..