Floristic composition, phenology, and conservation value of four peat bogs in Bucovina, with the presence of Betula nana

High in the misty mountains of the Eastern Carpathians, hidden within a landscape of wet, spongy ground, lie ecosystems known as raised bogs. These are not ordinary wetlands; they are living, breathing archives of the past, built layer by layer from the slow accumulation of dead plant matter in waterlogged, acidic conditions. The engine of this process is a group of mosses called Sphagnum, which act like giant sponges, holding vast amounts of water and creating the unique, nutrient-poor environment where only specialized plants can survive. Because these bogs are so sensitive to changes in water levels and climate, they are considered vital habitats that require careful protection. In Romania, these peatlands are home to a mix of ancient, cold-loving plants that have survived since the last ice age, making them not just ecological treasures but also living museums of a colder world. Understanding exactly what grows in these bogs, how the plants change through the seasons, and how different bogs compare to one another is essential for knowing how to protect them.

In a recent study, a researcher named Marian Trisciuc set out to explore four of these peat bogs in the Bucovina region of northern Romania: Poiana Stampei, Romanesti, Saru Dornei, and Gaina-Lucina. The goal was to take a close, non-invasive look at the plant life in each location to see how similar or different they were. The team did not dig up plants or take samples that would harm the delicate moss carpets. Instead, they walked into each bog and carefully observed a single, standardized square area measuring 25 square meters. Over the course of six visits between May and August 2026, they recorded every plant they saw, noting how many there were and what stage of life they were in, from budding to flowering to fruiting. They also took note of the physical conditions of each site, such as how high above sea level it was, the type of soil beneath the moss, and how much tree canopy covered the ground.

The investigation revealed that all four bogs share a common "core" of plant life, a familiar group of species that defines the character of these wet, acidic environments. In every single plot, the researchers found the mossy Sphagnum carpet, along with common bog plants like the star-shaped sundew, various sedges, and the cotton grass that gives the bogs their white, fluffy appearance in summer. They also found several species of blueberry and cranberry, which thrive in this acidic soil. Despite the different locations, the overall variety of plants was surprisingly consistent, with each site hosting between 12 and 13 different types of plants in the small area they studied. The two bogs of Romanesti and Saru Dornei were almost identical in their plant makeup, suggesting that the local conditions there are very similar.

However, one site stood out as truly unique: Gaina-Lucina. Located significantly higher up the mountain at 1,165 meters compared to the others, which sit between 860 and 920 meters, this bog hosted a plant that was absent from the other three sites. There, growing among the moss and shrubs, was Betula nana, or the dwarf birch. This is a small, shrub-like tree that is a "glacial relict," meaning it is a living remnant from the ice ages that once covered the region. In Romania, this plant is known to exist in only two peat bogs, making its presence at Gaina-Lucina a matter of high conservation importance. While the other bogs had a different type of birch, the dwarf birch at Gaina-Lucina marks it as a special place where ancient flora has managed to persist. The researchers also noted that the plants at Gaina-Lucina were slightly different in other ways, such as having a different type of cranberry and a distinct sedge, further setting it apart from the lower bogs.

The study also tracked how these plants changed over the summer months. The researchers watched the seasons unfold, noting when plants first showed green leaves, when they produced flowers, and when they began to set fruit or turn yellow. For most plants, the pattern was consistent across the sites, moving from growth to flowering to fruiting as the summer progressed. But there were interesting differences. At the high-altitude Gaina-Lucina, the common blueberry (Vaccinium myrtillus) stayed in its leafy, vegetative stage throughout the entire summer, never producing flowers during the observation period. In contrast, at the lower bogs, these same blueberries had already started to flower by early May. This suggests that the colder, higher environment of Gaina-Lucina delays the life cycle of its plants. The researchers also compared their 2026 findings with a few observations made at Gaina-Lucina in 2023, noting that some plants appeared in one year but not the other, which highlights how much these ecosystems can vary from year to year.

While the study provides a clear snapshot of these four specific spots, the researcher is careful to note that these findings describe only the exact points they visited, not the entire bogs. Because they looked at just one small square in each location, they cannot say for certain that the entire bog is exactly the same, but the data offers a solid foundation for future work. The presence of the rare dwarf birch at Gaina-Lucina confirms that this site is a priority for protection, while the similarities between the lower bogs suggest they share a common ecological story. The study concludes that while these peat bogs are built on a shared foundation of moss and acid-loving plants, the specific mix of species and the timing of their growth are shaped by local factors like altitude and soil type. For the conservation of these fragile, ancient landscapes, knowing exactly which plants are where, and how they respond to the seasons, is the first step toward ensuring they survive for the future.