Spatio-Temporal Variability Description of the Rare Species Lilium martagon L. in Different Habitat Conditions

Martagon Lily, Lilium martagon, belongs to geophytes inhabiting mainly forest communities in temperate regions of Europe and Asia and it is considered as a rare and endangered species in many regions. The presented investigations were conducted in three populations, occurring in forest habitats in Southern Poland: Wolski Forest (population 1), Mount Chełm (population 2), and Hrabeński Forest (population 3). At each site, 10 phytosociological relevés covering an area of 100 m² were taken. For each phytosociological relevé, the Shannon-Wiener, Pielou, and Simpson indices, as well as the number of species, were calculated. The detailed field studies were conducted in permanent study patches measuring 20 m × 20 m. The measurements of habitat conditions (e.g., number of species, soil moisture, light intensity at ground level, height of plant cover) were carried out in 2018. The observations of the abundance and developmental structure of stems, as well as selected traits (e.g., height, number and dimensions of leaves, number of flowers) were conducted in 2018-2023. The analysis of phytosociological relevés showed that the study sites in Wolski Forest and Mount Chełm were located in the Tilio cordatae-Carpinetum betuli oak-hornbeam forest association, while the study site in Hrabeński Forest was situated in the Dentario glandulosae-Fagetum mountain beech forest association. The statistical analysis confirmed that the greatest Shannon and Simpson index values, number of species, soil humidity, light intensity at ground level, and height of plant cover were recorded in Hrabeński forest. The greatest number of Lilium martagon stems and a lack of juvenile stems was found in population 3, while in less abundant populations-1 and 2-juvenile, immature, virginile, and generative stems were found. The statistical analysis showed that the highest immature and virginile stems with the greatest number of whorl leaves, as well as the substantial height of generative stems and number of whorl leaves observed in population 3, might be the result of growing in conditions of lateral shading provided by adjacent plants. The lowest height of immature and virginile stems recorded in population 1 and generative stems noticed in population 2 might be caused by them being overshaded by the canopy of surrounding trees. Moreover, the obtained results suggest the favourable impact of weather conditions during the meteorological spring and summer of 2019 on the growth of Lilium martagon stems. Nevertheless, the lack of a unified trend in the studied populations indicates the occurrence of site-specific temporal variability of individual traits. Considering the obtained results, it can be concluded that population 3 presents a much better state and prospects for persistence in the occupied site than populations 1 and 2. At the same time, it should be pointed out that further long-term observations of populations of Lilium martagon located in different habitat conditions are still strongly desired.