NATURA SLOVENIAE 23(2): 65-79 Prejeto / Received: 12. 9. 2021 
SCIENTIFIC PAPER Sprejeto / Accepted: 2. 12. 2021 
 
Biotehniška fakulteta Univerze v Ljubljani in Nacionalni inštitut za biologijo, Ljubljana, 2021 
 
 
 
Butterfly diversity (Lepidoptera: Papilionoidea) of  
Mt. Blegoš and Mt. Koprivnik (Škofjeloško hribovje, 
Slovenia) 
 
 
 
Luka ŠTURM1,a,*, Andrej PETERNEL2,a, Rudi VEROVNIK3 
 
 
1Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101,  
1000 Ljubljana, Slovenia; E-mail: luka.sturm@bf.uni-lj.si 
2Environmental Agency of Slovenia, Vojkova 1b, 1000 Ljubljana, Slovenia; E-mail: andrej.peternel@gmail.com 
3Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia;  
E-mail: rudi.verovnik@bf.uni-lj.si 
aauthors contributed equally 
*corresponding author 
 
 
 
Abstract. An overview of the surveys of butterfly fauna of Mt. Blegoš, Mt. Koprivnik and their surroundings is 
provided. In 2018, 14 surveys were performed and 80 butterfly species on eight transects recorded in the process. 
Additional surveys in 2019 and 2020 yielded 5 additional butterfly species. Among the butterflies observed, 
Parnassius mnemosyne, Lycaena hippothoe, Euphydryas maturna, Euphydryas aurinia, Melitaea britomartis, 
Melitaea diamina, and Pyrgus alveus are identified as vulnerable species, while both Phengaris arion and Phengaris 
alcon are classified as endangered species in Slovenia. The latter was found on two occasions in July 2018 and July 
2020 on a single locality. Eggs of P. alcon were found on the host plant Gentiana cruciata at the same locality. 
Despite the fact that many species characteristic of higher altitudes were observed, like Aricia artaxerxes, Pyrgus 
alveus, Erebia stiria and Lasiommata petropolitana, other, which had still been present a few decades ago, were 
not found (Parnassius apollo and Boloria pales). In this article, the problem of loss of important butterfly habitats 
in the region due to overgrowing, and the negative impacts of overgrazing is also highlighted. 
 
Key words: transect surveys, grazing, overgrowing, Phengaris alcon, Phengaris arion, Slovenia 
 
 
Izvleček. Raznolikost dnevnih metuljev (Lepidoptera: Papilionoidea) Blegoša in Koprivnika 
(Škofjeloško hribovje, Slovenija) – V članku predstavljamo popise favne dnevnih metuljev Blegoša in 
Koprivnika z njuno okolico. V letu 2018 smo opravili 14 popisov, med katerimi smo zabeležili 80 vrst metuljev na 8 
transektih. Med dodatnimi popisi v letih 2019 in 2020 pa smo opazili še 5 dodatnih vrst. Izmed zabeleženih metuljev 
spadajo Parnassius mnemosyne, Lycaena hippothoe, Euphydryas maturna, Euphydryas aurinia, Melitaea 
britomartis, Melitaea diamina in Pyrgus alveus med ranljive vrste, medtem ko sta Phengaris arion in Phengaris 
alcon klasificirana kot ogroženi vrsti za Slovenijo. Slednji je bil najden zgolj med dvema popisoma v juliju 2018 in 
2020 na eni sami lokaciji, prav tako pa smo na rastlini Gentiana cruciata našli njegova jajčeca. Kljub dejstvu, da 
smo opazili določene vrste značilne višje nadmorske višine, kot so Aricia artaxerxes, Pyrgus alveus, Erebia stiria in 
Lasiommata petropolitana, pa dveh, ki smo ju lahko opazovali še pred nekaj desetletji, nismo našli (Parnassius 
apollo in Boloria pales). V članku poudarjamo tudi problem izgube pomembnih habitatov v regiji zaradi zaraščanja 
in negativnega vpliva prekomerne paše. 
 
Key words: transektni popisi, pašništvo, zaraščanje, Phengaris alcon, Phengaris arion, Slovenija 
  
66 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
Introduction 
 
 
Škofjeloško hribovje, a roughly 25 km long mountain chain, is one of the highest in Slovenia 
outside the Alps (Perko & Orožen-Adamič 2001). It is positioned in the southwestern part of the 
country in the Gorenjska region. Due to its location it forms a barrier between three different 
climates – continental to the east and south, alpine to the north and sub-Mediterranean to the 
southwest. Due to its specific geological structure and climate it has a very diverse morphology, 
with a plethora of different habitats, which is reflected in a diverse fauna and flora found in the 
region (Ilešič 1938, Šifrer 1974). Due to the rich diversity and unique habitats, Mt. Blegoš is also 
a part of the Natura 2000 network (Blegoš; SI3000260; Ur. l. RS 2004a). 
 
The two highest points of the mountain chain are Mt. Blegoš (1,562 m) and Mt. Koprivnik 
(1,393 m), which have been surveyed for butterflies since the first half of the 20th century 
(Carnelutti 1980, Withrington 2003). However, apart from those general overviews, with only 
the most interesting species mentioned, there has been no extensive account of the butterfly 
fauna of the two mountains published. Nevertheless, Carnelutti (1980) provides some 
interesting observations, which can be used for the comparison with the current situation. He 
mentions several subalpine or alpine species for Mt. Blegoš, specifically Boloria pales, Parnassius 
apollo (already extinct at that time), Erebia euryale, E. medusa, and Pieris bryoniae. The only 
other faunistic survey, which only partially overlaps with our studied area, was done by Verovnik 
(2000), however, the aforementioned highest peaks were not visited at the time. 
 
Given the lack of systematic research, our main objective was to survey the butterfly fauna 
of the region and check for potential habitats and presence of the interesting species mentioned 
in the previous studies. We also provide an evaluation of the conservation status and threats to 
the butterflies in the region. 
 
 
Geographical characteristics of the region 
 
Škofjeloško hribovje is a mountainous region between the Poljanska Sora River to the south 
and the Selška Sora River to the north. It is a diverse mountainous landscape which merges to 
the west, just north of Cerkno, with Cerkljansko hribovje and its highest mountain Porezen 
(1,630 m), and with Mt. Lubnik (1,025 m), just above Škofja Loka, reaches its easternmost 
point. Mt. Blegoš and its neighbour, Mt. Koprivnik, are located north of the villages of Volaka 
and Gorenja Žetina, respectively, and are the highest peaks of the region (Šifrer 1974). 
 
The two mountains are surrounded with an old Paleozoic, presumably Silurian, shale and 
chives, while their peaks are predominantly composed of younger dolomites and shell limestone, 
which lie atop the Carboniferous layers. The limestone and dolomites are especially predominant 
at the top of Mt. Blegoš (Ilešič 1938, Šifrer 1974, Marinček & Wraber 1980). Due to the very 
complex geological structure composed of mainly impermeable rocks, which represents a 
transition point between the Alps and the Karst, the surrounding area of Mt. Blegoš is densely 
intersected with smaller gorges and ravines created by strong temporary torrents (Šifrer 1974). 
 
 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 67 
NATURA SLOVENIAE 23(2): 65-79 
Mt. Blegoš and Mt. Koprivnik have, like the major part of Škofjeloško hribovje, a typical 
continental climate characteristic of the Ljubljana basin, with alpine climate influences at higher 
altitudes, especially above 1,300 m. On warmer southern slopes, the influence of the 
neighbouring sub-Mediterranean climate is evident (Ilešič 1938, Marinček & Wraber 1980). The 
wider area of Škofjeloško hribovje has high annual rainfall of around 1,800–2,000 mm on 
average (Nadbath 2010, Vertačnik & Bertalanič 2017), while the highest parts of Mt. Blegoš and 
Mt. Koprivnik receive on average between 2,000–2,600 mm annually (Vertačnik & Bertalanič 
2017). The annual mean temperatures for the highest parts of Mt. Blegoš are between 4–6 °C, 
and 6–8 °C for lower parts (including Koprivnik) while the average temperature in July is 
between 12–14 °C for Mt. Blegoš and 14–16 °C for Mt. Koprivnik (Marinček & Wraber 1980, 
Vertačnik & Bertalanič 2017).  
 
Given the amount of precipitation and specific geology, the region is characterised by lush 
vegetation, especially dense mixed woods, consisting predominantly of Fagus sylvatica, Abies 
alba and Picea abies. F. sylvatica is especially common on the limestone and dolomite near the 
top of Mt. Koprivnik and in particular Mt. Blegoš, while the surrounding area is mostly covered 
by mixed woods (49 %) with a predominance of conifers. Those woods have the characteristics 
of sub-alpine mixed forest of Luzulo-Abieti-Fagetum praealpinum or Luzulo-Fagetum montanum 
praealpinum, depending on the altitude. Above 1,450 m they are considered as part of Fagetum 
subalpinum forests (Ilešič 1938, Marinček & Weber 1980). Ash, an important larval host plant 
of Euphydryas maturna, is also found in the area, especially around »Likar’s hayfield« locality. 
 
The highest parts of Mt. Blegoš are covered with extensive grasslands and pastures, which 
are present also on the southern slopes. These, despite showing the characteristics of a true 
alpine grasslands and pastures in some places, are of anthropogenic origin, which can be seen 
in an advanced overgrowing of uncut and un-grazed areas, as well as in a very high upper tree 
line limit, which nowadays reaches up to 1,500 m. Also typical of Paleozoic shales are low 
woodland shrubs and vegetation, like Vaccinium myrtillus, Calluna vulgaris and different species 
of ferns, which are especially common in the overgrown grasslands of Mt. Koprivnik (Ilešič 1938, 
Marinček & Weber 1980).  
 
One of the main agricultural activities in the region and especially Mt. Blegoš is grazing. 
Before 1900, it was very widespread, also extending to other parts of the mountain chain  
(e.g. Mt. Koprivnik). After 1900, however, with the newly formed border between Italy and 
Slovenia, the grazing activity started to decline (Ilešič 1938). This has been even more 
prominent in recent decades when there was also a shift from sheep to now predominant cattle 
grazing (own observations). 
 
 
 
Materials and Methods 
 
Description of the surveys 
 
Despite a few observations of butterflies around Mt. Blegoš, Mt. Koprivnik and their 
surroundings, no thorough research has ever been undertaken in this region. Thus, a more 
extensive survey was performed in order to determine the most important species and habitats 
68 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
from the conservation perspective. We established surveys on 8 transects/localities and, 
weather permitting, visited them at least once every second week from 27. 5. to 8. 9. 2018, 
counting the number of butterflies (species and individuals) in the process. 
 
Table 1. The list of transects surveyed during the study. Coordinates are given in a WGS 84 projection. In the case of a 
broader locality, the observations were made near the transect location, but are sometimes not restricted to the 
indicated habitat type of the transect. Start/End refer to start and end points of each transect. 
Tabela 1. Seznam transektov, ki smo jih vzorčili med študijo. Koordinate so podane v WGS 84 projekciji. V primeru širše 
lokacije so bili popisi opravljeni v bližini transekta, a niso bili vedno omejeni le na habitatni tip, značilen za tisti transekt. 
Start/End se nanašata na začetno in končno točko transekta. 
No. 
Name 
(ENG/SLO) 
Description 
Habitat 
type 
Start End 
Length 
[m] 
1 Meadow under Mt. 
Koprivnik/Travnik 
pod Koprivnikom 
Mt. Koprivnik, 
meadow 500 m S 
of the top 
Intensive 
grassland 
X: 46.171691, 
Y: 14.140815; 
Alt.: 1112 m 
X: 46.171944, 
Y: 14.142006; 
Alt.: 1116 m 
120 m 
2 Potok/Potok Potok, meadow 
500 m SE of the 
village entre 
Intensive 
grassland 
X: 46.180063, 
Y: 14.110464; 
Alt.: 970 m 
X: 46.179911, 
Y: 14.109219; 
Alt.: 921 m 
150 m 
3 Mt. Koprivnik/ 
Koprivnik 
Mt. Koprivnik, 
meadow 200 m SE 
of the top 
Extensive 
grassland 
X: 46.174310, 
Y: 14.143750; 
Alt.: 1268 m 
X: 46.175569, 
Y: 14.141969; 
Alt.: 1368 m 
300 m 
4 Likar’s hayfield/ 
Likarjeva senožet 
Mt. Blegoš,  
1900 m S of the 
top 
Extensive 
grassland 
X: 46.146215, 
Y: 14.119547; 
Alt.: 1051 m 
X: 46.148255, 
Y: 14.118667; 
Alt.: 1137 m 
300 m 
5 Forest clearing/ 
Gozdna poseka 
Mt. Blegoš, 650 m 
SE of the top 
Forest 
clearing 
X: 46.159735, 
Y: 14.118791; 
Alt.: 1333 m 
X: 46.161318, 
Y: 14.118619; 
Alt.: 1376 m 
170 m 
6 Forest by the 
macadam/ 
Gozd ob kolovozu 
Mt. Blegoš, 850 m 
S of the top 
Forest 
clearing 
X: 46.156421, 
Y: 14.113011; 
Alt.: 1296 m 
X: 46.154801, 
Y: 14.107443; 
Alt.: 1229 m 
570 m 
7 Mt. Blegoš: 
meadow under the 
hilltop/Blegoš: 
travnik pod vrhom 
Mt. Blegoš, 300 m 
S of the top 
Pasture 
meadow 
X: 46.161210, 
Y: 14.112718; 
Alt.: 1473 m 
X: 46.162834, 
Y: 14.110422; 
Alt.: 1441 m 
270 m 
8 Mt. Blegoš: 
hilltop/Blegoš: vrh 
Mt. Blegoš, 150 m 
S of the top 
Pasture 
meadow 
X: 46.163187, 
Y: 14.112729; 
Alt.: 1509 m 
X: 46.163685, 
Y: 14.115937; 
Alt.: 1498 m 
330 m 
 
The transect surveys were performed according to the Pollard walk method (Pollard 1977). 
In total, 14 surveys were conducted on all transects on the given dates: 27.5., 3.6., 10.6., 17.6., 
26.6., 1.7., 7.7., 22.7., 30.7., 4.8., 13.8., 19.8., 28.8. and 8.9., all in 2018. The only exception 
is the transect No. 2 – Potok, where only 13 surveys were performed – the survey wasn’t 
performed on 22.7.2018 due to bad weather conditions. After extensive surveys in 2018, 
additional visits were made on some of the localities near the transects in 2019 and 2020, to 
check for additional expected species. In 2019, one additional survey was performed on localities 
near transects Nos. 1, 3, 6 (all on 2.6.) and 4 (14.7.), while in 2020, one additional survey was 
performed on localities near transects Nos. 1, 2, 6 (all 13.4.) and 8 (20.7.), two additional 
surveys on localities near transects No. 5 and 7 (4.7. and 20.7.), and three additional surveys 
on locality near transect No. 4 (11.4., 4.7. and 20.7.). Unlike in 2018, the Pollard walks were 
not carried out in 2019 and 2020. During this research, no major floristic surveys were 
performed and only certain larval host plants are pointed out in this article. 
 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 69 
NATURA SLOVENIAE 23(2): 65-79 
The selected transects included four main different habitat types (pastures, intensive 
grasslands, extensive grasslands and forest clearings) at different altitudes, in order to cover as 
many different ecotypes as possible. Two transects/localities were selected for each habitat 
type. The individual butterflies were caught (if necessary) with a butterfly net and determined 
using Tolman & Lewington’s (2008) butterfly guide. 
 
 
Data analysis  
 
We calculated a population density of each species for each transect separately. The 
population density of species is expressed as number of individuals per survey per 100 m of 
transect, and was adapted from Čelik & Verovnik (2020) with slight alterations:  
 
𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑠𝑝𝑒𝑐𝑖𝑒𝑠 = (𝑋 ∗ 100 𝑚)/(𝑌 ∗ 𝑍 )   (1) 
 
Where X is the sum of all imagines of species observed in 2018 on a transects during all 
surveys, Y is the number of surveys performed on a transect (13 for locality »Potok«, and 14 
for all other localities) and Z is the length of the transect in metres.  
 
 
 
Figure 1. Position of transects for butterfly surveys on Mt. Blegoš and Mt. Koprivnik in Škofjeloško hribovje.  
Slika 1. Mesta transektov za popise dnevnih metuljev na območju Blegoša in Koprivnika v Škofjeloškem hribovju. 
  
70 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
 
Figure 2. Habitats of selected transects/localities on Mt. Blegoš, Mt. Koprivnik and their vicinity: A) Potok; B) Meadow 
under Mt. Koprivnik; C) Mt. Koprivnik; D) Mt. Blegoš: meadow under the hilltop; E) Mt. Blegoš: hilltop; F) Likar’s 
hayfield; G) Forest clearing; H) Forest by the macadam (main part); I) Forest by the macadam (the part with rocky 
cliffs). 
Slika 2. Življenjski prostori izbranih transektov/lokacij na Blegošu, Koprivniku in njuni okolici: A) Potok; B) Travnik pod 
Koprivnikom; C) Likarjeva senožet; D) Blegoš: travnik pod vrhom; E) Blegoš: vrh; F) Likarjeva senožet; G) Gozdna 
poseka; H) Gozd ob kolovozu (glavni del); I) Gozd ob kolovozu (del s skalnimi stenami). 
 
 
 
Results  
 
 
Altogether, 80 species and 5,012 specimens were observed between 27.5. and 8.9.2018. 
Among these, 1,050 specimens and 52 species were observed on pastures, 890 specimens and 
53 species in intensive grasslands, 763 specimens and 53 species inside forest clearings, and 
2,309 specimens and 65 species in extensive grasslands. The complete butterfly survey of 
Mt. Blegoš, Mt. Koprivnik and their surroundings, which also included additional location-specific 
surveys in 2019 and 2020, yielded altogether 85 species (Tab. 2). Of these, 9 species are listed 
as vulnerable, while two are considered endangered in either Slovenia or Europe (Tab. 2). Most 
of those species were found on more than one occasion and in more than one locality. 
  
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NATURA SLOVENIAE 23(2): 65-79 
Table 2. Population densities of individual species per survey per 100 m of transect/locality in 2018, with the addition of 
species observed only in 2019 or 2020. Nomenclature follows Verovnik (2019). X – Species found only in the vicinity of 
the transect; Y – Species observed only in 2019 and/or in 2020, but not in 2018. 
Tabela 2. Populacijska gostota posamezne vrste na vzorčenje na 100 m transekta v 2018, z dodatkom vrst, ki so bile 
najdene samo v letu 2019 ali 2020. Poimenovanje je povzeto po Verovnik (2019). X – Vrsta najdena samo v okolici 
transekta; Y – Vrsta opažena samo v letu 2019 in/ali 2020, ne pa tudi v letu 2018. 
Family Species\ Locality 1 2 3 4 5 6 7 8 
Papilionidae Papilio machaon Y  0.05 0.17  X X 0.02 
 Iphiclides podalirius    Y     
  Parnassius mnemosyne 0.06 0.05 1.17 0.02 2.52 0.04 0.66 0.17 
Pieridae Aporia crataegi  0.05       
 Pieris brassicae 0.06 0.05 0.24 0.10 0.21 0.31 0.13 0.09 
 Pieris rapae 0.12 0.10 0.07 0.12 0.08 0.29 0.16 0.09 
 Pieris bryoniae 
     0.01 0.03  
 Pieris napi 0.24 0.72 0.83 0.55 0.88 0.65 0.21 0.06 
 Anthocharis cardamines X 
 X  0.08 0.09 0.03  
 Colias alfacariensis/hyale 
  0.02 X    0.02 
 Colias crocea 0.71 0.05 0.05 0.24 0.08 0.09 0.42 0.39 
 Gonepteryx rhamni 
 0.10 0.02 0.02 0.17 0.30 0.08  
  Leptidea sinapis/juvernica 1.49 0.41 1.07 0.10 0.04 0.09 0.05  
Lycaenidae Satyrium ilicis    0.02     
 Satyrium spini 
   1.71  0.25   
 Callophrys rubi 
   0.02  Y 0.03  
 Lycaena phlaeas Y 
   0.04    
 Lycaena virgaureae 
 0.10 0.07 0.05 0.04    
 Lycaena tityrus 0.48 0.21 0.12 0.02 
  0.08 0.02 
 Lycaena alciphron 0.36 0.21 0.07 
     
 Lycaena hippothoe 2.74 0.10 0.26 0.02 
  0.40 0.09 
 Celastrina argiolus 
  0.02  X 0.03 0.03  
 Cupido minimus 0.42 0.10 0.21 0.55 0.08 0.01 0.53 0.37 
 Phengaris alcon 
      0.08  
 Phengaris arion 
   0.02  0.03 0.03  
 Plebejus argus 0.18 
 0.07 0.07   0.16  
 Aricia agestis 0.95 
 0.43 0.02 X  0.08 0.13 
 Aricia artaxerxes X 
 0.12 Y   0.03 0.06 
 Cyaniris semiargus 0.48 0.72 0.38 0.02 0.04 0.03 0.66 0.89 
 Lysandra bellargus 0.30  0.05 0.05   0.05 0.02 
 Lysandra coridon 0.06 1.85 0.14 1.43 0.21 0.03 1.90 0.19 
 Polyommatus dorylas 0.48   0.02   0.34 0.15 
  Polyommatus icarus 0.83 0.21 0.07 0.12 0.04  1.30 0.19 
Riodinidae Hamearis lucina  0.21 0.10 0.05  0.01 0.03 0.06 
Nymphalidae Apatura iris     X    
 Limenitis populi 
    X    
 Limenitis reducta  
     0.03   
 Issoria lathonia 
  0.07 X 0.17 X X 0.02 
 Argynnis paphia 
 0.36 0.14 0.14 0.97 0.25 X 0.02 
 Speyeria aglaja 0.18 0.31 0.43 0.02 0.13 
 0.21 0.09 
 Fabriciana adippe 
  0.05 Y 0.08 0.03   
 Brenthis daphne 
 0.05 0.12 0.05 0.13 0.01   
 Boloria euphrosyne Y 0.05 0.45 0.52 1.34 0.39 0.08 X 
 Boloria dia 3.33 0.15 0.07 X 0.17 
   
 Aglais io 0.12 0.10 0.14 0.07 3.15 0.05 X 0.02 
 Aglais urticae X 0.10 0.07 0.14 0.08 0.10 0.21 0.63 
 Polygonia c-album 
 0.10   X 0.01 0.03  
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NATURA SLOVENIAE 23(2): 65-79 
Family Species\ Locality 1 2 3 4 5 6 7 8 
 Nymphalis polychloros 
 X    0.01   
 Nymphalis antiopa  Y       
 Vanessa atalanta X 0.15 0.02 0.05 0.21 0.08 X 0.02 
 Vanessa cardui 0.12 
 0.07 0.26 0.04 0.05 0.13 0.04 
 Melitaea cinxia 0.54 0.05 0.05 
   0.03  
 Melitaea phoebe 
 0.05 0.14 0.05   0.03  
 Melitaea diamina 
 0.10 0.36      
 Melitaea britomartis    Y     
 Melitaea didyma 1.55 X 0.02 0.05 
 0.01   
 Melitaea athalia 2.32 1.64 1.81 0.14 0.13 X 0.03 
 
 Euphydryas maturna 
  0.07 0.07     
 Euphydryas aurinia 
  0.02 0.36 0.29    
 Melanargia galathea 0.48 3.44 4.45 6.90 X 0.19 0.05 0.04 
 Hipparchia fagi 
   X     
 Minois dryas 
   0.07     
 Brintesia circe  0.06 X 0.05 0.21 0.04 0.01 
 0.02 
 Erebia ligea 
 0.15 0.50 0.05 0.08 0.05   
 Erebia aethiops 
 0.10  1.07 X 0.23  Y 
 Erebia medusa 0.42 1.38 1.64 1.55 X 0.13 0.37 0.41 
 Erebia stiria 
     0.43   
 Erebia euryale     Y   Y 
 Maniola jurtina 1.96 3.64 0.52 0.24 0.13 0.06 0.05 0.02 
 Coenonympha pamphilus 4.46 0.10 0.31 0.12 0.04 
 1.14 0.15 
 Coenonympha arcania 0.06 2.41 2.19 11.67 0.04 0.33 0.05 0.02 
 Pararge aegeria 
    X Y   
 Lasiommata megera 
   0.14  0.01   
 Lasiommata maera 
 0.10 0.33 0.43 0.04 0.64 0.08 0.04 
 Lasiommata petropolitana 
     Y   
  Lopinga achine  0.15  0.02  0.03   
Hesperiidae Pyrgus malvae 0.18 0.15 0.17 0.10 Y  0.21 0.02 
 Pyrgus alveus 
    0.04  0.03 0.02 
 Erynnis tages 0.12 0.05 0.07 0.02 0.08 0.03 0.71 0.11 
 Carterocephalus palaemon 
 0.21 0.36      
 Heteropterus morpheus 
   X     
 Thymelicus lineola 0.60 
 0.02    0.03  
 Thymelicus sylvestris X 0.31 0.33 Y 0.08 
   
 Hesperia comma 0.60 0.62 0.14 0.14 0.46 0.01 8.28 2.12 
  Ochlodes sylvanus X 1.08 3.00 0.93 0.13 0.41 0.16  
Number of species 85 43 49 57 63 49 48 50 39 
 
 
It is worth noting that the detailed data on exact dates of finding the species and their 
abundances were not included, due to the sheer amount of obtained information (eight tables 
were merged in one), but are available on request from the authors of the paper.  
 
  
 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 73 
NATURA SLOVENIAE 23(2): 65-79 
Table 3. Conservation status of butterfly species observed on Mt. Blegoš, Mt. Koprivnik and their surroundings in 
Slovenian and in European context. The European conservation status of butterfly species is based on van Swaay et al. 
(2010), while the Slovenian conservation status is based on rules on the classification of endangered plant and animal 
species in the Red List (Ur. l. RS 2002). LC – least concern species, NT – near threatened species, VU – vulnerable 
species, EN – endangered species. 
Tabela 3. Varstveni status ogroženih vrst metuljev, najdenih na Blegošu, Koprivniku in v njuni okolici v Sloveniji in 
Evropi. Status ogroženosti v Evropi bazira na van Swaay et al. (2010), medtem ko varstveni status v Sloveniji bazira na 
pravilniku o uvrstitvi ogroženih rastlinskih in živalskih vrst v rdeči seznam (Ur. l. RS 2002). LC – vrsta zunaj nevarnosti, 
NT – vrsta blizu ogroženosti, VU – ranljiva vrsta, EN – prizadeta vrsta. 
Family Species 
Conservation 
status in 
Slovenia 
Conservation 
status in 
Europe 
Inclusion into the 
Decree on 
protected wild 
animal species  
(UR. l. RS 2004b) 
Papilionidae Parnassius mnemosyne VU NT Appendices 1, 2 
Lycaenidae Lycaena alciphron VU LC Not included 
 Lycaena hippothoe VU LC Not included 
 Phengaris alcon EN LC Appendices 1, 2 
 Phengaris arion VU EN Appendices 1, 2 
Nymphalidae Melitaea diamina VU LC Not included 
 Melitaea britomartis VU NT Not included 
 Euphydryas maturna VU VU Appendices 1, 2 
 Euphydryas aurinia VU LC Appendices 1, 2 
 Lopinga achine LC VU Appendices 1, 2 
Hesperiidae Pyrgus alveus VU LC Not included 
 
 
Table 4. Comparison of all eight transects and the number of butterflies/species found during 2018 surveys.  
Tabela 4. Primerjava vseh osmih transektov in števila metuljev/vrst, popisanih v letu 2018. 
Transect/locality (No.) Habitat type 
No. species on 
wider locality 
No. species on 
transect 
Transect 
length [m] 
1 - Meadow under Mt. Koprivnik intensive grassland 40 34 120 
2 - Potok intensive grassland 48 45 150 
3 - Mt. Koprivnik extensive grassland 57 56 300 
4 - Likar’s hayfield extensive grassland 58 53 300 
5 - Forest clearing forest clearing 47 38 170 
6 - Forest by the macadam forest clearing 45 42 570 
7 - Mt. Blegoš: meadow  
under the hilltop 
pasture 50 45 270 
8 - Mt. Blegoš: hilltop pasture 37 36 330 
 
 
  
74 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
Discussion 
 
 
Until now, the butterfly fauna of Mt. Blegoš and Mt. Koprivnik has been relatively poorly 
studied, as the latest records date back more than 15 (Withrington 2003) or more than 40 years 
(Carnelutti 1980). The relatively high number of species recorded in the surveyed area, 
compared to similar areas such as Šentvid plateau (Torkar et al. 2013) or Cerkljansko-Idrijsko 
region (Verovnik 2000), could be explained by sampling during the main adult butterfly season 
in eight different localities, coupled with sampling during the period of 3 years, as well as the 
influence of different climates. Compared to previously mentioned surveys (Verovnik 2000, 
Torkar et al. 2013), almost 10 % more species have been observed around Mt. Blegoš and  
Mt. Koprivnik. As Mt. Blegoš with its 1,562 m is considered a low mountain, many species found 
here are typical of higher altitudes (above 1,000 m). These are: Pyrgus alveus, Phengaris alcon 
f. rebeli, Lasiommata petropolitana, Pieris bryoniae, Aricia artaxerxes, Erebia stiria and Erebia 
euryale (Verovnik et al. 2012). 
  
Among the species mentioned, P. bryoniae, P. alveus, A. artaxerxes and P. alcon f. rebeli 
are occasionally also found in the lowland areas (Verovnik et al. 2012). E. stiria and  
L. petropolitana are more petrophilous and were observed on cliffs along a macadam road below 
Mt. Blegoš (Fig. 2 - I). The latter species was already mentioned for Mt. Blegoš by Withrington 
(2003), but without precise location. P. alcon f. rebeli was first recorded in 2018, but only a 
single imago was observed on the transect, and not more than 3 were seen in the locality 
altogether. However, in July 2020, at least 5 imagines were present, giving hope that this tiny 
population might still survive. On the other hand, a related species, Phengaris arion, was found 
in three localities, two of those situated at lower altitudes. The species is localised but 
widespread in the wider region, including the village of Trebija (Verovnik et al. 2012), Slajka 
Hill, Makovce plateau, and Jelovica below Mt. Blegoš (own observations in 2020).  
 
Among other observed butterflies, Euphydryas species were most common in extensive 
meadows, but are present also in wider area of Škofjeloško hribovje (Verovnik et al. 2012). The 
species E. euryale and Erebia ligea were found only on few occasions during the 2018 surveys, 
but were very common in 2017 and 2019 (own observations). Biennial development, resulting 
in much higher adult numbers in alternate years, is a common feature of this genus (Warren 
1936, Kleckova et al. 2015). The low abundance of both species in 2018 could be attributed to 
constant rainy afternoons that dominated during flight period and to the lack of suitable nectar 
sources.  
 
When compared to the nearby Cerkljansko-Idrijsko region and particularly its highest peak 
Mt. Porezen (1630 m), the butterfly fauna of Mt. Blegoš and Mt. Koprivnik is surprisingly richer, 
also containing more species characteristic of altitudes above 1,000 m (Verovnik 2000). This is 
especially evident even when comparing the number of species for the relatively close survey 
dates of 27.7.–2.8. for Mt. Porezen (4 localities) and 30.7. for Mt. Blegoš and Mt. Koprivnik 
(8 localities). The number of species found on these dates on Mt. Blegoš and Mt. Koprivnik 
reaches 42, while the number of species found on Mt. Porezen was only 24. This might be 
partially explained by the non-carboniferous soil dominating Mt. Porezen, and different climate 
surrounding the mountains. In terms of species characteristic for altitudes above 1,000 m, only 
Erebia pronoe, which is still common around the peak of Mt. Porezen, was not recorded on 
 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 75 
NATURA SLOVENIAE 23(2): 65-79 
Mt. Blegoš. Interestingly, there is a specimen of E. pronoe collected by Mate Hafner in 1911 in 
the collection of Slovenia NHM (Verovnik et al. 2012) from Mt. Blegoš, a record neglected in the 
overview by Carnelutti (1980).  
 
Since the latest records of biodiversity in 1980, agricultural activities became more intensive. 
Yet, while predominantly lowland habitats are mostly machined and fertilized, many habitats at 
higher altitudes are in the final overgrowth phase due to isolated intensive grazing (sheep, goats 
and cattle) and abandonment of mowing (Ilešič 1938). The most obvious is the overgrowing of 
the higher meadows of Mt. Koprivnik, where mowing or grazing is completely absent. Only the 
meadows by the macadam road leading to Črni Kal below Mt. Koprivnik are intensively mown. 
On the other hand, the intensification of agriculture impacted the grazing activity in the highest 
meadows of Mt. Blegoš. Due to isolated grazing with cattle, some larval food or host plants, 
such as Gentiana cruciata and once common Arnica montana, are being diminished in number. 
Lower meadows are sparse and occur mainly in very steep and exposed areas, such as »Forest 
by the macadam« and »Likar’s hayfield« transects. The latter presents the largest meadow area, 
where overgrowing is less problematic for the time being. Thus, habitat loss, due to rapid 
overgrowing and intensive grazing, is the greatest danger to the biodiversity of local butterflies. 
Some butterflies, like Parnassius apollo, have already disappeared presumably owing to this 
very reason.  
 
Based on the uniqueness of the habitat and the diversity of butterflies found we defined  
4 nature conservation important localities for butterflies in the region, based on the surveyed 
transect routes: »Mt. Koprivnik«, »Likar’s hayfield«, »Forest by the macadam« and  
»Mt. Blegoš: meadow under the hilltop«. 
 
Transects »Mt. Koprivnik« and »Likar’s Hayfield« are the two most important sites with 
extensive meadows. Unfortunately, both localities, especially meadows of »Mt. Koprivnik«, are 
subject to overgrowing. Meadows of »Likar’s hayfield« are especially characterised by the minor 
sub-Mediterranean influence as indicated by the presence of thermophilous species such as 
Satyrium spini, Lysandra coridon, Minois dryas, and Hipparchia fagi. The area consists of south-
facing dry bushy grasslands, where in addition Libelloides macaronius is abundant, despite not 
being reported for the Škofjeloško hribovje (Devetak et. al. 2007). However, the find is not 
surprising, as it was also recently discovered in NW Slovenia on the Šentvid plateau (Torkar 
2021). Both »Mt. Koprivnik« and »Likar’s Hayfield« have the highest number of species recorded 
and are important for both – unique fauna and flora.  
 
The »Forest by the macadam« represents the longest and most heterogeneous transect, 
consisting mainly of forest clearings, which is in the centre characterised by approximately  
50 m of rocky cliffs. This unique habitat for the region hosts the two petrophilous species  
L. petropolitana and E. stiria. Despite not being listed as threatened in Slovenia or wider, their 
isolated occurrence on Mt. Blegoš is still of conservation importance.  
 
The last among the important transects is »Mt. Blegoš: meadow under the hilltop«, which 
represents the largest open pasture partially intensively grazed by cattle. The impact of intensive 
grazing is manifested by trampled ground and low herbal height. The steeper rockier parts to 
the northeast of Mt. Blegoš peak are now mostly overgrown by trees. The locality is of particular 
conservation importance due to the presence of a small colony of P. alcon f. rebeli and its host 
plant G. cruciata. 
76 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
From the conservation point of view, the presence of both Euphydryas species, Parnassius 
mnemosyne, Lopinga achine and P. arion, all included in the Annexes II and/or IV of the Habitats 
Directive, (OJ EC 1992) is of great importance. Their presence merits further investigations into 
their population size, distribution, threats and could provide foundations for long term 
conservation of their habitats and butterfly richness as a whole in both studied mountains. 
 
 
 
Figure 3. Selection of butterfly species of conservation concern found on Mt. Blegoš, Mt. Koprivnik and their 
surroundings: A – Euphydryas aurinia (Mt. Koprivnik, 3.6.2018); B – Euphydryas maturna (Likar’s hayfield, 10.6.2018); 
C – Phengaris alcon f. rebeli (Mt. Blegoš: meadow under the hilltop, 20.7.2020); D – Parnassius mnemosyne  
(Mt. Koprivnik, 4.7.2017); E – Lasiommata petropolitana (Forest by the macadam, 2.6.2019) 
Slika 3. Nekatere izmed naravovarstveno pomembnih vrst dnevnih metuljev, najdenih na Blegošu, Koprivniku in v njuni 
okolici: A – Euphydryas aurinia (Koprivnik, 3.6.2018); B – Euphydryas maturna (Likarjeva senožet, 10.6.2018);  
C – Phengaris alcon f. rebeli (Blegoš: travnik pod vrhom, 20.7.2020); D – Parnassius mnemosyne (Koprivnik, 4.7.2017); 
E – Lasiommata petropolitana (Gozd ob kolovozu, 2.6.2019) 
  
 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 77 
NATURA SLOVENIAE 23(2): 65-79 
Conclusions 
 
The complete butterfly survey of Mt. Blegoš, Mt. Koprivnik and their surroundings, which 
took place between 27.5. and 8.9.2018 and included additional location-specific surveys in 2019 
and 2020, yielded altogether 85 species, which amounts to 47 % of the butterfly fauna of 
Slovenia (Verovnik 2019). Among the surveyed species, 11 are defined as vulnerable or 
endangered in Slovenia or Europe (Ur. 1. RS 2002, Van Swaay et al. 2010). 
 
The most interesting find is P. alcon f. rebeli, observed only in the high-lying pastures of 
Mt. Blegoš, not mentioned in the previous surveys. Abandonment of extensive farming, 
overgrowing of habitats and intensive grazing are the most likely causes for the absence of 
Boloria pales. The localities were also monitored for the presence of Sedum album, a larval food 
plant for the locally already extinct butterfly P. apollo (Carnelutti 1980), but unfortunately the 
plant has never been found. 
 
The authors conclude that Mt. Blegoš and its wider surroundings are an important and 
biodiversity rich area worth preserving, and that its inclusion in the Natura 2000 conservation 
network is well deserved. The study also reveals some of the problems with the habitat loss 
which might arise in the future, due to the abandonment of mowing and grazing in certain 
areas. In order to preserve such habitats, the old farming practices should be re-implemented, 
wherever possible. 
 
 
 
Povzetek  
 
 
V članku predstavljamo popise favne dnevnih metuljev Blegoša in Koprivnika z njuno okolico, ki so 
potekali med 27. majem in 8. septembrom 2018 na 8 izbranih transektih. Med 14 popisi nam je uspelo 
zabeležiti 80 vrst dnevnih metuljev in njihovo število na posamezni popisni lokaciji/transektu. Med dodatnimi 
popisi v letih 2019 in 2020 smo opazili še 5 novih vrst metuljev, ki jih predhodno na teh lokacijah nismo 
našli. Vzorčenje je potekalo po principu metode transektnega monitoringa, kjer opazovalec počasi hodi po 
vnaprej začrtani poti in šteje metulje v vse smeri 2,5 m okoli sebe (levo, desno, spredaj in zgoraj) (Pollard 
1977). Posamezne transekte, vključene v raziskavo, smo zbrali na podlagi nadmorske višine, dostopnosti in 
tipa habitata. Izmed zabeleženih metuljev zbujajo največ pozornosti Parnassius mnemosyne, Lycaena 
hippothoe, Euphydryas maturna, Euphydryas aurinia, Melitaea britomartis, Melitaea diamina in Pyrgus 
alveus, ki jih uvrščamo med ranljive vrste, medtem ko sta Phengaris arion in Phengaris alcon klasificirana 
kot ogroženi vrsti za Slovenijo. Medtem ko je bil P. arion najden na več kot eni lokaciji, je bil P. alcon 
zabeležen zgolj med dvema popisoma julija 2018 in 2020 na enem samem transektu. Njegova jajčeca smo 
leta 2018 našli tudi na rastlini Gentiana cruciata na isti lokaciji, a so bile do naslednjega popisa v juliju vse 
rastline že popasene. Med popisom smo posebno pozornost posvečali tudi vrstam, ki jih najdemo v 
visokogorju oz. na višjih nadmorskih višinah (nad 1000 m). Čeprav dveh vrst, ki smo ju tu beležili še pred 
nekaj desetletji, nismo našli (Parnassius apollo, Boloria pales) (Carnelutti 1980), so bile nekatere druge, kot 
so Aricia artaxerxes, Pyrgus alveus, Erebia stiria in Lasiommata petropolitana, najdene med popisi, zadnji 
dve vrsti zgolj na eni sami lokaciji. Slednja lokacija je bila tudi edina s strmejšim skalnatim previsom, kakršne 
je na Blegošu sicer že večinoma prerasel gozd. Posledično pričakujemo, da sta E. stiria in L. petropolitana 
tu redki vrsti, ki bi že v prihodnosti lahko dokončno izginili. Med popisom smo iskali tudi rastlino Sedum 
album, hranilno rastlino lokalno že izginulega metulja Parnassius apollo, vendar neuspešno. Izginitev 
hranilne rastline tega metulja gre pripisati zaraščanju skalnatih predelov Blegoša, kar je verjetno povezano 
tudi z izginitvijo še ene visokogorske vrste Boloria pales. V tem članku smo zato poudarili prav problem 
78 Luka ŠTURM et al.: Butterfly diversity of Mt. Blegoš and Mt. Koprivnik / SCIENTIFIC PAPER 
NATURA SLOVENIAE 23(2): 65-79 
izgube pomembnih habitatov v regiji zaradi zaraščanja in negativnega vpliva prekomerne paše. Na območju 
Koprivnika in določenih delih Blegoša je pašna aktivnost namreč opuščena, kar se kaže v zaraščanju 
ekstenzivnih suhih travišč, po drugi strani pa se na drugih predelih Blegoša pojavlja problem intenzivne paše 
z govedom, ki ogroža predvsem travniške vrste na vrhu in tik pod njim. V članku smo ocenili še pomembnost 
posameznih transektov kot tudi celotnega območja pri vključitvi v Naturo 2000. 
 
 
 
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