Comparison of the phenological, ecological, and vegetative characteristics of two rare endemic species, Scrophularia fatmae and Scrophularia erzincanica adapted to different altitudes specific to Erzincan/ Türkiye

The ecological interactions between plants and pollinators significantly contribute to global diversity. Hence, focusing on the phenology of plants at various altitudes yields valuable insights into understanding how climate change impacts ecosystems and its association with evolutionary processes. Specifically, this study examines Scrophularia erzincanica, a species native to Erzincan (Türkiye), adapted to lower altitudes, and S. fatmae, an obligate alpine species. The aim was to elucidate the phenological, ecological, and floral characteristics relevant to pollination in both species comparatively. Significant differences were observed in the duration of phenological events, inflorescence architecture, style, and staminode position. Notably, S. fatmae exhibited longer durations for phenological events. Additionally, distinct floral arrangements were evident S. fatmae displayed clustered flowers while S. erzincanica exhibited loosely distributed ones. In S. erzincanica, the staminode's placement in the middle of the corolla created a physical barrier, potentially preventing nectar theft, influencing pollinator selection, prolonging their visit duration, and coordinating flower movements triggered by pollinators. Conversely, in S. fatmae, the staminode remained concealed and positioned near the corolla base. Pollinator visits were shorter in S. fatmae but longer in S. erzincanica. The harsher environmental conditions and lower pollinator density and diversity in alpine regions compared to lower altitudes likely contribute to these differences. Despite sharing common ancestors, these observed phenological disparities in species might stem from selective pressures exerted by varying altitudes, driving these species along divergent evolutionary paths. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.