A Hidden Swamp

On Kostanjevica hill north of the village of Bevke on the western part of Ljubljana Marshes landscape park something strange is hiding in the middle of a dense spruce forest.q

This hole in the forest is a really bizarre natural phenomenon, a quirk of geology, hidrology, and biology: an isolated raised bog called Mali plac.

This raised bog formed at least 15.000 years ago in a bowl-shaped depression on the west side of Kostanjevica hill, at the junction of (semi-permeable) dolomite and (impermeable) sandstone. Water couldn’t escape from the bowl and a swamp formed, with peat mosses slowly accumulating until they were over five metres thick. On this soft carpet a totally unique ecosystem was established, and it somehow survived to this day.

Completely isolated from Ljubljana Marshes (it’s bottom is a couple of meters higher than the flat plain of the Marshes) and sufficiently hidden from the prying hands of humans Mali plac is a treasure trove of rare and endangered species of flora and fauna. The only extant turtle species in Slovenia – European pond turtle (Emys orbicularis) – lives here, the wet lean soil is perfect for the carnivorous round-leaved sundew (Drosera rotundifolia), there are newts and dragonflies and butterflies and frogs and numerous birds – and, of course, mosquitoes.

Mali plac in August 2017 (left) and June 2021 (right)

We visited Mali plac in August 2017 and you can see how different it can look on the photos above … Mali plac has no water inlet and is completely dependent on rainwater; the late summer of 2017 was much drier than this year’s spring and early summer – the almost-dried-up swamp turned red back then, and is lush green now.

While Mali plac is quite remote, well-meaning humans still managed to interfere with it and do some real damage. First they cut an outflow to dry it up and almost destroyed it, then they panicked and dammed the outflow which made the water level rise too much, flooding the delicate peat mosses and again almost destroying the fragile ecosystem. A comprehensive survey and scientific efforts to undo the damage are underway.

Mali plac is a magical place. A very cool educational path leads around it, managed by Škrateljc (link in Slovene); they do great tours for the kids, showing you the hidden swamp in such a way you believe there really are elves guarding it (and inciting the mosquitoes to attack you). If you find yourself in Ljubljana with a couple of hours to spare, give them a call!

Kite aerial photos shot with Nikon P330 on a Royal 69 sled kite (August 2017 photo shot with Canon A810 on a rokkaku kite).

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