Silver Lime (Tilia tomentosa Moench) in Forest Vegetation at the Western Edge of the Natural Distribution

Silver lime is a thermophilic, calciphile species that thrives in xero-mesophilic forest communities. The westernmost edge of its natural distribution is Zrinska Gora Mountain in central Croatia, where it is found in almost all types of forest vegetation, albeit with varying frequencies. Its ecological optimum is in specific ravines and grooves, where it forms the mesophilic, relict broad-leaved ravine forest community Polysticho setiferi-Tilietum tomentosae. This research was conducted on two levels. Firstly, the communities of Zrinska Gora were analyzed as the westernmost edge of the natural distribution. Secondly, the ecology of the Tilia tomentosa communities in the western part of its distribution (Croatia, Bosnia and Herzegovina, Hungary, and Serbia) was observed. Analysis of Ellenberg-type indicator values for 74 communities from the western Balkans revealed a slight trend of decreasing thermophilicity and increasing acidophilicity toward the western edge of the distribution area. Silver lime peripheral populations on Zrinska Gora develop under unique ecological conditions. The soil reaction of all communities falls below the lower limit of the optimal range for its development, and the relict association experiences lower temperature values compared to the other communities. All in all, the results of this study provide insights into the adaptability of silver lime to climate change.