Natural Monument Vlčí Jámy

From a geological perspective, Blatenský vrch is the peak of a tectonically uplifted ridge with asymmetric slopes composed of biotitic granite of the Krušné hory pluton and greisens (metamorphic granite typical for the Krušné hory area). In the greisens of the Blatenský massif, Sn-W-Li-Mo-Bi mineralization is developed. The main useful component was the mineral cassiterite (tin ore, SnO2). The presence of topaz, fluorite, and tourmaline is also characteristic.

The surroundings of Vlčí jámy are formed by a spruce monoculture, which was significantly damaged by emissions and subsequently by wind calamities. Much more interesting is the species richness of ferns in Vlčí jámy itself. For example, Blechnum spicant, Phegopteris connectilis, Asplenium septentrionale, Asplenium trichomanes, Cystopteris fragillis, and Gymnocarpium dryopteris grow here. Cold-tolerant species of mountain flora also occur here, such as Ranunculus platanifolius and Homogyne alpina. The natural monument Vlčí jámy is also the only place in the Czech Republic where Mielichhoferia mielichhoferiana - a rare moss that is tied to substrates with exposed copper ore veins - occurs. This species was recorded here in 1997.

In the granite walls of Vlčí jámy, Phoenicurus ochruros nests, and until the 1980s, Tetrao urogallus regularly appeared on Blatenský vrch. Additionally, one can encounter Zootoca vivipara or Anguis fragilis here. Recently, a critically endangered Eliomys quercinus was also accidentally discovered here - more details about this finding can be found in previous articles.

Cave ice from Vlčí jámy was used in the past for food cooling. In 1813, after the battle of Leipzig, six carts of ice were reportedly taken to military hospitals from here. In the summer of 2005, a group of citizens from nearby Klingenthal extracted about two tons of cave ice with the aim of building a snowman and winning a competition organized by a certain regional radio station. According to newspaper reports from that time, they did not win the contest, and each of the six perpetrators was fined a (quite mild) penalty of 20,000 CZK. The cave ice is gradually returning to Vlčí jámy, although this act of vandalism disrupted the unique microclimate. The presence of ice further increases the temperature difference between the cold air, which naturally sinks to the bottom of the deep pit, blocking the entry of warm air in the summer. Thus, a layer of very cold air forms above the ice layer, which practically does not move. The formation of new cave ice is influenced by a number of factors. Climate changes and deforestation of the surroundings of Vlčí jámy contribute to the rocks heating more in the summer, but the colder winters in recent years have had a positive effect on the layer of newly forming cave ice.

A nature trail leads from Horní Blatná to the natural monument Vlčí jámy, ending at Blatenský vrch. However, there are many similar sinkholes in the Krušné hory - Vlčí jámy is among the most well-known.