Islands of long-hidden treasures 1.1
Peat bogs or peatlands are among the greatest natural treasures not only in the Telč region and the Bohemian-Moravian Highlands but also in many other places on our planet. Their natural, economic, and social value is priceless. They influence the global and local climate, play an essential role in the water regime of the landscape, belong to the so-called biodiversity hotspots, preserve information about the development of nature, offer unforgettable aesthetic experiences, and have become a source of inspiration for many artists. At the same time, they are very vulnerable, and, more than anywhere else, even minor disturbances can have significant consequences. Their beauty is indeed fragile.
What are peat bogs?
Peatlands are a particular type of wetlands, unique and different in many ways from all other wetlands and other types of environments. Their uniqueness lies in the fact that organic matter builds up faster than it breaks down. The result is the formation and deposition of peat, sediment of biological origin based on incompletely decomposed plant carcasses.
The peat bogs were named after the mosses of the genus peatbog which, together with other mosses, sedges, and shrubs, are the primary component of the vegetation of peatlands of the Arctic and temperate zones. Like other wetlands, peatlands are among the most threatened habitats affected by both human activity and natural processes.
How are peat bogs formed?
On permanently waterlogged sites, the decomposition of organic matter can be slowed down considerably due to specific conditions, especially lack of oxygen and excess water, but also other factors. The biomass production then outweighs its degradation, its residues accumulate and are converted into peat in a process similar to the formation of charcoal. This process takes a very long time, and the peat layer usually grows by only one millimeter per year. That is why peat, like coal, is a non-renewable resource.
What types of peat bogs do we know?
According to water saturation, we distinguish peat bogs into fens (minerotrophic) and raised bogs (ombrotrophic), between which we can find transitional peat bogs. The different types represent the developmental stages of the peatland in relation to the growth of the peat layer.
Fens are fed by groundwater or surface water with different mineral content. They often began to develop in the Middle Ages, with the beginning of permanent settlement and deforestation of the landscape. In some places, however, the underlying peat layers date from the end of the last Ice Age, i.e., 13 000-10 000 years ago. A particular type of peat bogs are peat meadows, i.e., young peat bogs up to 50 cm thick, the formation of which was conditioned by human activity.
Transitional peat bogs are saturated both by groundwater, which is less available to them due to the thickening peat layer, and by rainwater. They are more acidic and poorer in nutrients. They are not very abundant in the Bohemian-Moravian Highlands.
Raised peat bogs have a layer of peat so thick that they do not reach the groundwater and are dependent on atmospheric precipitation. They are very poor in nutrients, and the communities that inhabit them are not very diverse. In central Europe, they are usually found in mountainous areas.
What is peat?
Peat is the surface organic layer of soil that contains incompletely decomposed plant bodies. It is usually covered with ‚peat-forming vegetation‘, which gradually dies off, its remains accumulating under living plants and turning into peat. Like coal, oil, or asphalt, it is so-called organogenic sediment.
Witnesses of the ancient past
Optimal conditions for peatland formation occurred after the end of the last ice age when the permafrost melted and released water. Later, peat bogs were formed, for example, in the context of deforestation of the landscape, often during its colonization by people.
Thanks to slower decomposition processes, pollen grains and remains of plant and animal bodies, so-called macro-residues, remain „preserved“ in peat bogs. Their study, especially palynological analysis (examination of pollen grains), can contribute significantly to forming an idea of how the landscape evolved in the past.