Jesenova Pond lies at the bottom of a sinkhole in the forest region of Jesenova, near the community of Kosi, on the edge of Lužina Forest.
The pond is in a shallow sinkhole at the edge of Lužina Forest in Kastav. Although located near a footpath, it’s not easy to spot and is difficult to find because it’s not featured in any maps. Surrounded by a dense forest, the pond is overshadowed by trees and encircled by a dry-stone wall. According to our in-house typology, it could be classified as a “forest pond at the bottom of a sinkhole, enclosed by a dry-stone wall” (Photo 1). In the southern part of the Municipality of Viškovo is another such pond, Kapitovac, which we also visited recently.
When we visited Jesenova Pond we noticed an accumulation of aquatic plants, in particular the curly-leaf pondweed (Potamogeton crispus). We didn’t spot any amphibians in the pond, however, despite the spawning season being under way. What we did notice were bubbles of gas (marsh gas?), rising from the bottom of the pond strewn with fallen leaves and breaking the surface of the water every now and then. Could this be the reason behind the absence of amphibians?
Sycamore (Acer pseudoplatanus) and lime trees prevail in the forest vegetation around the pond (Photo 2). The sycamore suggests that the sinkhole has a more humid and probably colder micro climate and that the soil is deep and humid. In contrast to this type of forest, the forest along the margin of the sinkhole largely consists of thermophilic (heat-loving) oriental hornbeam trees. In terms of botany, an interesting feature of the forest region of Jesenova is the presence of the spurge-laurel (Daphne laureola) which is very rare in those parts.