Monday 5 June 2017

Call of the mountain

This week we made our traditional yearly hike on mount Nanos (1262 m) in western Slovenia. This mountain is the most prominent landmark in the region and rises high above the Karst and the Vipava valley. Its rocky and grassy slopes, combined with the extensive beech forests on its northern side are home to a great plant and animal biodiversity. Here we present some of the wildlife we encountered while ascending the mount from Razdrto.
The extensive meadows of the Nanoščica river basin around the village of Razdrto are good for White Storks Ciconia ciconia, which until recently also bred in the village (westernmost stork's nest in Slovenia). Storks can be still seen in the area, but they breed a few kilometers eastwards; one certainly in the village of Hrašče (see previous post). The above individual was enjoying the mowed meadows by the local road Postojna-Razdrto. 
Rock Bunting Emberiza cia is a very common bird on Nanos' rocky slopes, inhabiting primarly the termophilous woodland of hop-hornbeam Ostrya carpinifolia and manna ash Fraxinus ornus, interspersed with limestone outcrops and screes. In fact Slovenia's largest densities of Rock Buntings are found along the Nanos, Vipava and Trnovski gozd ridges. While ascending the mountain we heard and observed several individuals. Another typical inhabitant of rocky slopes and steep limestone cliffs is the Peregrine Falco peregrinus. This year a pair probably bred somewhere close to Nanos' summit, as we observed at least two noisy juveniles and an adult bringing them food.
The real star of this mountain is the colourful Rock Thrush Monticola saxatilis. A nesting pair was observed by the main path, not far from Nanos' summit. This area (last pic) hosts generally one or two pairs of the species and the birds can be sometimes observed quite close to the path. This time we were lucky to observe both male and female taking food to the nest, located somewhere in a steep gully. In this short video you can hear the male's calls as well as the song at the end (watch in HD).
Rock Thrush is a scarce breeder in Slovenia, inhabiting south-facing, grassy and rocky mountain slopes in the west of the country. The Julian Alps are its stronghold, while smaller populations are also found on the southern edge of Trnovski gozd, Nanos ridge, Karst edge (Kraški rob) and the Snežnik plateau. It benefits from mountain pastures (grazing of cattle and sheep) and has disappeared from many places as a consequence of grazing abandonment. The habitat on Nanos is still quite suitable, but like in many other places, the grasslands are in the process of overgrowing as grazing has been abandoned. With no actions, in a few decades of natural succession, the grasslands will turn into woodland. Species like Rock Thrush, Rock Partridge Alectoris graeca (already extinct on Nanos), but also Skylark Alauda arvensis will thus disappear.
The delicate white flowers of Daphne alpina adorn the rocky slopes of Nanos, while its wonderful vanilla scent is carried around by the wind. This species is mainly found on rocky and sunny areas of the high Karst, especially on its plateaus. Despite its scientific name, it is quite rare in the Alps.
In the warm termophilous woodlands of Nanos' southern slopes, the first Lilium carniolicum are already in flower. We counted some 5-7 specimen, while on the plateau's extensive grasslands, the buds were still well closed and will bloom in a few weeks. The same goes for the purple-coloured L. martagon, whilst in lower lying areas of the Karst, we already noticed some Lilium bulbiferum in flower (see below).
Three different species of Iris were in bloom on Nanos. The first of the above in Iris illyrica (I. pallida ssp. illyrica) which has large blue flowers and is usually found in dry, sunny places, on the south-facing slopes. The next, Iris sibirica ssp. erirrhiza is mainly found on top of the plateau, growing in small depressions on rocky grasslands; it is an endemic subspecies of the the high Karst area and represents the mountain counterpart of I. s. sibirica (a lowland species of wet meadows - see this). The third and smallest of the three is Iris graminea, already described in one of the previous posts. We found it growing very commonly both on Nanos' wooded slopes and on the grassy plateau.
Marsh Fritillary Euphydryas aurinia is a widespread butterfly in Slovenia, found in three different habitats: dry grasslands, wet meadows and alpine pastures. It is a Natura 2000 species and potentially vulnerable to habitat loss: overgrowing of grassland habitats or draining of wet meadows. On Nanos the species is quite commonly found and even described on a local information board.
Erysimum sylvestre growing around Nanos' summit in rocky places and a Swallowtail Papilio machaon feeding on its nectar. The butterfly is one of the most widespread species in Slovenia.
This is the only documentative (flight) shot of a Clouded Apollo Parnassius mnemosyne we could get. Up to 7 individuals were flying low over the grass, not far from the top of Nanos, but never stopping for a moment. We thus had to try some flight shots to document this scarce species. It inhabits mainly montane grasslands of the Karst and is more widespread than its red-spotted relative P. apollo (a typical alpine species).
Astragalus carniolicus is very common on Nanos as this mountain represents its locus classicus (typical location). Being an Illyric species it is distributed from Slovenia in the north to Montenegro in the south. In Slovenia it grows also on the southern edge of Trnovski gozd, in Čičarija and the lower Karst (western Slovenia).
We found several stands of Traunsteinera globosa on the plateau's grasslands, although most were not in full bloom. This is a quite interesting orchid species, usually found at higher elevations and overall quite scarce. Although it has no nectar, insects (its pollinators) are nevertheless attracted to it as its flowers resemble those of Scabiosa columbaria.
Another interesting orchid on Nanos was the tiny Coeloglossum viride, well hidden in the short grass. Being quite small and mostly green it's quite difficult to spot and is frequently overlooked (and trampled on!).
When we conquered Nanos' summit we were glad to find the blooms of Allium ursinum still at large in the beech forest close to the mountain hut. A real spectacle of colour and smell!
In the beech forest close to the hut we also found a pair of nesting Coal Tits Periparus ater, entering a tree crevice and delivering food to two chicks. Surprisingly, around the hut we also found a singing Common Redstart Phoenicurus phoenicurus.
Lilum bulbiferum is now in bloom at lower elevations in the Karst. In this part of the country it is the commonest of the three lily species found in Slovenia. Grows on meadows and woodland edges, never in large numbers. At the base of each leaf has a small bulbil used for unsexual reproduction - when the bulbil falls to the ground a new plant can originate from it.