Habitat extremity promotes the survival of rapidly declining orchid Neotinea ustulata in Poland

Grasslands are global hotspots of biodiversity, but in many regions the abandonment of traditional management has led to secondary succession and the disappearance of specialized grassland species. An example of such a species is the burnt-tip orchid Neotinea ustulata (syn. Orchis ustulata), formerly known from ~130 sites across Poland, which has experienced a rapid population decline. However, the species and the reasons for its disappearance have not yet been the subject of comprehensive ecological research in Poland. Therefore, in the present study we sampled Polish localities of N. ustulata outside the mountainous areas where its presence has been reported in the 21st century and collected both population and ecological data. Besides describing the current distribution and ecological niche of the species in Poland, we aimed to identify environmental conditions at both local (vegetation and soil) and regional (landscape and climate) scales that favour the survival of the most viable populations of N. ustulata. Of the 24 localities confirmed in the 21st century, we found no individuals of N. ustulata in eight during our survey in the spring and summer of 2022, while further six populations were much smaller than in previous inventories. One population, located in an active quarry, could not be surveyed. Only nine populations of N. ustulata were found to be relatively stable. Compared to extinct and declining populations, stable populations of N. ustulata occupied unshaded xeric grasslands on shallow soils in areas with a more arid climate. Our study suggests that, due to ineffective or non-existent conservation efforts, habitat extremity appears to play a crucial role in the continued survival of this species in Poland.