plants
Article
Phytogeographic Characteristics of Montane Coniferous Forests
of the Central Balkan Peninsula (SE Europe)
Tijana Ilić
, Nevena Kuzmanović
, Snežana Vukojičić and Dmitar Lakušić *
Institute of Botany and Botanical Garden “Jevremovac”, Faculty of Biology, University of Belgrade, Takovska 43,
11000 Belgrade, Serbia
* Correspondence: dlakusic@bio.bg.ac.rs
Citation: Ilić, T.; Kuzmanović, N.;
Vukojičić, S.; Lakušić, D.
Phytogeographic Characteristics of
Abstract: We investigated taxonomic and endemic richness, patterns of spatial distribution, cenotic
and spatial diversification, and chorological and life form spectra of montane coniferous forests in
the central part of the Balkan Peninsula. We collected information on 1435 taxa (1351 at the level of
species and 84 subspecies) with 65,289 species-occurrence data, published in 1930 original plots with
a total area of about 215 ha in the analysis. All statistical analyses (univariate and multivariate) were
performed on binary matrices prepared for different levels of analysis. Our main results showed that
the montane coniferous forests of the central Balkan Peninsula represent very species-rich vegetation.
At the same time, the high proportion of endemics indicated that the montane coniferous forests
of the central Balkan Peninsula differ significantly from Central European and boreal forests of a
similar type. Furthermore, we found that there were regional differences in the species composition
of the coniferous forests of the Balkan Peninsula, and that the primary centers of floristic richness
are located in the area of the central and continental Dinarides. This latter finding suggested that
the true centers of the richness of European coniferous forests are located south of the Limestone
Alps—Western Dinarides—Carpathian Foothills line in Romania, which used to be considered the
center of the richness of the coniferous forests in Europe.
Keywords: floristic richness; endemics; life forms; area types; coniferous forests; Balkan peninsula
Montane Coniferous Forests of the
Central Balkan Peninsula (SE
Europe). Plants 2022, 11, 3194.
https://doi.org/10.3390/
1. Introduction
plants11233194
Concerning the centers of world plant diversity, the Balkan Peninsula, as part of the
Mediterranean basin, is recognized as one of the few extratropical biodiversity hotspots [1–3].
The main hotspots for species richness are confined to mountainous areas for European
coniferous forests, particularly in the Calcareous Alps, the north-western Dinarides, and
the Western Carpathians [4]. The present floristic diversity of the Balkan Peninsula is
the result of heterogeneity of environmental factors, geological-historical changes, and
human influences [5]. In the Balkan Peninsula and, especially, in the central part, various
floristic influences from Central Europe, the boreal and arctic regions of Eurasia, and the
central and east Mediterranean meet in the form of long-lasting, multidirectional migration
processes of florogenesis from the Tertiary to the present, with emphasis on the Quaternary
glacials [6,7]. As one of the major glacial refugia, the Balkan Peninsula was crucial in the
formation of European flora and fauna [8–10].
The heterogeneity of environmental factors, as one of the strongest drivers of floristic
diversity, is best represented by the diversity of habitat types found in the studied area.
Since different plants inhabit different phytocoenoses, depending on their ecological and
coenotic affiliation, knowledge of the floristic composition of the different vegetation
types is crucial to understand the overall biodiversity of any area. In this sense, the
exceptional richness of plant species recorded in the Balkan Peninsula is a consequence of
the extraordinary diversity of its vegetation [11,12], represented by the presence of eleven
of the fourteen zonal, and all five azonal, types of natural vegetation in Europe [13].
Academic Editor: Riccardo Motti
Received: 21 October 2022
Accepted: 14 November 2022
Published: 22 November 2022
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Plants 2022, 11, 3194. https://doi.org/10.3390/plants11233194
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Most of the conifers living on the Balkan Peninsula belong to the group of Balkan
endemics, which includes the following: Abies borisii-regis Mattf., Abies cephalonica Loudon,
Picea omorika (Pančić) Purk., Pinus peuce Griseb., Pinus nigra subsp. dalmatica (Vis.) Franco,
or Balkan–Apennine endemic, Pinus heldreichii Christ. The Balkan Peninsula conifers also
include the Balkan–Asia Minor–Crimean sub-endemics, Pinus nigra subsp. pallasiana (D.
Don) Holmboe. These facts, as well as the fact that only a few species have a broader
European (Abies alba Mill., Pinus nigra J. F. Arnold subsp. nigra) or Eurasian distribution
(Picea abies (L.) H. Karst., Pinus sylvestris L.), indicate that the coniferous forests of the
Balkan Peninsula represent an extremely interesting biogeographical phenomenon, the
floristic diversity of which has not yet been extensively analyzed.
In Europe, 46% of forests are predominantly coniferous [14]. They are mostly distributed in the taiga biome in northern and northeastern Europe and in the high mountain
ranges, which belong to the temperate deciduous broadleaved forest biome, but they also
exist in the EU-Mediterranean and Supra-Mediterranean areas of southern Europe [5,13,15].
In the Balkan Peninsula, mono- and oligo-dominant coniferous forests are common
in the Mediterranean and temperate zones, from the coast to altitudes above 2000 m. All
forests are differentiated into two major formations, Mediterranean–Supra-Mediterranean
and temperate–boreo-montane [11–13]. According to Mucina et al. [12], the first formation
includes the following: (a) Relict Supra-Mediterranean Hellenic fir and black pine montane
forests (Abietion cephalonicae Horvat et al., 1974); (b) Supra-Mediterranean cypress forests of
Crete (Aceri sempervirentis-Cupression sempervirentis Barbero et Quézel ex Quézel et al., 1993)
and (c) Thermo–Meso-Mediterranean pine forests of the central and eastern Mediterranean
(Pinetalia halepensis Biondi, Blasi, Galdenzi, Pesaresi et Vagge in Biondi et al., 2014). The
second formation consists of: (d) Holarctic coniferous forests on oligo-trophic and leached
soils at high altitudes in the mountains (Vaccinio-Piceetea Br.-Bl. in Br.-Bl. et al., 1939) and
(e) Relict pine forests on calcareous and ultramafic substrates (Erico-Pinetea Horvat 1959).
Only six coniferous species characterize the montane coniferous forests of the central Balkan Peninsula. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) are
widespread species in the boreal, temperate, and boreo–montane zones of Euroasia, reaching their southernmost distribution in the Balkan Peninsula; fir (Abies alba) is distributed
in the high mountains of central and southern Europe. Bosnian pine (Pinus heldreichii)
is a sub-endemic of the Balkan and Apennines, and Macedonian pine (Pinus peuce) and
Serbian spruce (Picea omorika) are Balkan endemics [6,16]. Apart from the Norway spruce
(Picea abies) and Scots pine (Pinus sylvestris), other conifer species studied here do not occur
in the boreal coniferous forests of Europe [13].
In the context of the importance of biodiversity protection, coniferous forests have
been identified as high-priority habitats. Thus, the Habitats Directive of the European
Union, as the main legislative instrument in the field of nature conservation [17] in the
Balkan Peninsula, recognizes seven European natural habitat types, including one priority
habitat type which is in danger of disappearance and whose natural range mainly falls
within the territory of the European Union (9530 * (Sub-)Mediterranean pine forests with
endemic black pines).
Although there are numerous data collected during the intensive development of
floristic and phytocenological science over the 20th century, which constitute a valuable
source of information for the description, quantification, and analysis of biodiversity at
local and regional scales [18,19], recent studies that systematically address various aspects
of Balkan floristic diversity [6,7,19–46] did not pay full attention to the floristic diversity
and phytogeography of the coniferous forests of the Balkan Peninsula.
Considering that the Balkan Peninsula has received less attention from phytogeographers than other parts of Europe and that, in the case of the Balkans, simple figures of
exceptional species richness do not illustrate the fundamental importance of the region
in terms of its conservation value [47], this work aimed to investigate: (1) the taxonomic
and endemic richness and diversity, (2) the patterns of spatial distribution, (3) the cenotic
and spatial diversification, (4) the chorological and life-form spectra of montane coniferous
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forests in the central part of the Balkan Peninsula, thus, helping to demonstrate the uniqueness and distinctiveness of the floristic diversity and phytogeographic characteristics of
this part of Europe, and (5) to emphasize the special value of this type of habitat in the
protection of nature and biodiversity.
2. Materials and Methods
2.1. Study Area, Forest Types, and Data Gathering Principles
The area under study covers the territory of the Balkan Peninsula, from Snježnik
Mountain in Croatia in the north-west to the Pelister Mountain in North Macedonia in
the south and the Central Stara planina Mountain in the east. (Figure 1). The considered
geographical area of the Balkans follows the phytogeographical boundaries given by
Reed et al. [48], while the classification of the mountain systems of the Balkans follows
Stevanović et al. [37].
Figure 1. Distribution of coniferous forests in the Balkan Peninsula—position of the analyzed plots of
coniferous forests.
For the purpose of analyzing various aspects of phytogeographic characteristics of
mountain coniferous forests in the central part of the Balkan Peninsula, we adapted the concept of “operational ecological units” [49], where the unit on which analyses are performed
is a plant formation that has a well-defined floristic composition, unique physiognomy,
similar habitat conditions and, consequently, similar ecological functions. The analyses
were conducted at three hierarchical levels, representing the ecological and geographical
diversities of coniferous forest formations in the investigated area.
At the first level, we distinguished two basic groups that unite: (A) boreo-montane
and subalpine spruce and pine forests, which, according to Bohn et al. [13], belong to
the vegetation formation D, Mesophytic and hygromesophytic coniferous forests, and
(B) Sub-Mediterranean orotemperate dry relict pine forests on carbonate and ultramafic
substrates, which, according to Bohn et al. [13], belong to the vegetation formation K,
Xerophytic coniferous forest. In the text, we used the composite name “dark spruce forest
type (Vaccinio-Piceetea)” for the first group and “light pine forest type (Erico-Pinetea)” for
the second.
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Within these two basic forest types, we singled out six units at the second level
that correspond to forest formations dominated by the main coniferous species that
make up the forests of the Balkan Peninsula. Thus, within the dark coniferous forests,
four units were singled out: Norway spruce forests (Vaccinio-Piceion), Scots pine forests
(Pinion sylvestris), Serbian spruce forests (Piceion omorikae), and Macedonian pine forests
(Pinion peucis). Within the light coniferous forests, two units were singled out: Bosnian pine
forests (Pinion heldreichii) and ultramafic black pine forests (Orno-Ericion).
Finally, the third level defines the operational units that make up the geographical
variants of coniferous forests, the occurrence of which is registered in the basic mountain
systems on the Balkan Peninsula, namely, Dinarides, Scardo-Pindic mountains, Rhodope
mountains, and Balkan (Stara planina) mountains. According to Stevanović et al. [37],
mountains are classified into four mountain systems and 16 mountain groups. Hierarchical
relationships, names, and codes of the operational units are listed in Table 1.
The names of plant formation used in this manuscript have no formal syntaxonomic
meaning, but are used as associative names, corresponding to the different forest types.
The total estimated extent of the area considered for this study is 1,209,553 hectares,
while the estimated area occupied by operational ecological units at Levels I and II is shown
in Table 1. The evaluation of these areas was recalculated, based on “Map of Natural
Vegetation of Europe in scale 1:2,500,000” [13].
Table 1. “Operational ecological units” and hierarchical levels of coniferous forests in the Balkan
Peninsula for which the analyses were performed.
Level
Forest Types
Codes
Estimated Area of
Occupancy (in ha)
I
Dark spruce forest types
(Vaccinio-Piceetea)
Vaccinio-Piceetea
1,059,824
II
Norway spruce forests
(Vaccinio-Piceion)
Vaccinio-Piceion
635,389
III
Norway spruce forests
(Vaccinio-Piceion) in Dinarides
Vacc_Pic_Din
III
Norway spruce forests
(Vaccinio-Piceion) in Scardo-Pindic
mountains
Vacc_Pic_ScPind
III
Norway spruce forests
(Vaccinio-Piceion) in Rhodope
mountains
Vacc_Pic_Rhod
III
Norway spruce forests
(Vaccinio-Piceion) in Balkan mountains
Vacc_Pic_Balk
II
Scots pine forests (Pinion sylvestris)
Pinion silvestris
III
Scots pine forests (Pinion sylvestris)
in Dinarides
Pin_syl_Din
III
Scots pine forests (Pinion sylvestris) in
Rhodope mountains
Pin_syl_Rhod
III
Scots pine forests (Pinion sylvestris) in
Balkan mountains
Pin_syl_Balk
II
Serbian spruce forest
(Piceion omorikae)
Piceion omorikae
318,880
6697
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Table 1. Cont.
Estimated Area of
Occupancy (in ha)
Level
Forest Types
Codes
III
Serbian spruce forest (Piceion
omorikae) in Dinarides
Pic_omor_Din
II
Macedonian pine forests
(Pinion peucis)
Pinion peucis
III
Macedonian pine forests (Pinion
peucis) in Dinarides
Pin_peuc_Din
III
Macedonian pine forests (Pinion
peucis) in Scardo-Pindic mountains
Pin_peuc_ScPind
III
Macedonian pine forests (Pinion
peucis) in Rhodope mountains
Pin_peuc_Rhod
III
Macedonian pine forests (Pinion
peucis) in Balkan mountains
Pin_peuc_Balk
I
Light pine forest types
(Erico-Pinetea)
Erico-Pinetea
149,730
II
Bosnian pine forests
(Pinion heldreichii)
Pinion heldreichii
133,334
III
Bosnian pine forests (Pinion heldreichii)
in Dinarides
Pin_heldr_Din
III
Bosnian pine forests (Pinion heldreichii)
in Scardo-Pindic mountains
Pin_heldr_ScPind
III
Bosnian pine forests (Pinion heldreichii)
in Rhodope mountains
Pin_heldr_Rhod
II
Ultramafic black pine forests
(Orno-Ericion)
Orno-Ericion
III
Ultramafic black pine forests
(Orno-Ericion) in Dinarides
Orn_Eric_Din
98,858
16,395
In accordance with the adapted concept of plant formation as “operational ecological
units”, we used vegetation data from original phytocoenological tables in research articles,
book chapters, master’s theses, and dissertations, published between 1938 and 2012, as the
source for species occurrence data (Table S1), with data from seven publications exported
from the Balkan Vegetation Database [50,51]. In total, data from 1930 plots with a total
area of approximately 215 ha (2,147,291 m2 ) were included in the analyses. Although the
area where the data on species occurring in coniferous forests were collected was small
(only 2.15 km2 ), particularly when compared to the extent of the entire region, it was, at
the same time, very representative. Namely, the size of the plots included in the analysis
varied between 60 and 20,000 square meters, with an average of 986 m2 , which corresponds
to the area representing the floristic composition of forest stands and is commonly used for
phytocenological research on forests. In addition, the 1930 plots, from which the species
data were taken, are very well distributed over the range of mountain coniferous forests of
the Central Balkan Peninsula (Figure 1).
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In each plot, we grouped multiple records of the same species occurring in more than
one vegetation layer (e.g., tree species occurring in the herbaceous, shrub, and tree layers),
removed non-vascular plants, and counted the number of species. Finally, a dataset of
65,289 species-occurrence data was formed, on which various analyses were performed.
Since the distribution of records by year for the entire area had a normal distribution,
and the distribution of records by year was essentially different for different mountain
systems (Figures S1–S5), all records were included in the analysis, regardless of possible
bias from long-term vegetation changes.
For non-georeferenced, or inaccurately georeferenced, plots, secondary accurate georeferencing was performed in Ozi Explorer and on Google Earth. Centers of floristic
richness were shown in MGRS maps of 50 × 50 km, based on the UTM projection [52].
Taxon concepts and nomenclature largely followed the Checklist for Central Europe
adopted for the EuroVegChecklist expert system in the JUICE program [12]. For a smaller
number of species, primarily restricted to the area of the Balkan Peninsula, the nomenclature
generally followed the Euro + Med PlantBase.
For defining areal groups, we used the classification based on the distribution area
types proposed by Meusel et al. [53,54] and Meusel and Jaeger [55], which were modified
for the territory of Serbia by Stevanović [56].
The basic life forms of the plants were determined according to Raunkiaer [57], supplemented by Mueller-Dombois and Ellenberg [58] and Stevanović [56].
2.2. Statistical Analyses
All statistical analyses (univariate and multivariate) were performed on binary
(presence–absence) matrices prepared for different levels of analysis.
Similarity and distance indices (Jaccard), as well as diversity indices, were calculated
using the package Past v. 2.17 [59]. We used two indicators of diversity: species richness
(a term more common when discussing biogeographical issues), to describe the absolute
species number in the designated area, and the LogS/LogA index of species density, to
describe the number of species per unit.
Cluster analysis (paired group with Jaccard distances) was performed using the
package Past v. 2.17 [59], while principal coordinate analysis, using Jaccard distances, was
performed using Canoco 5 [60].
3. Results and Discussion
3.1. Species Richness and Diversity
We collected information on 1435 taxa (1351 at the level of species and 84 subspecies)
in the coniferous forests of the Balkan Peninsula, with 65,289 species-occurrence data.
This number of taxa represented 22% of the estimated total number of vascular plant taxa
in the Balkan Peninsula [36,47,61] and 12% of the total European flora [62] Considering
that in the Alps, as a major European mountain system, approximately 5500 species have
been recorded [62], the number of 1435 taxa recorded only in the coniferous forests of the
mountain systems of the central part of the Balkan Peninsula represented a considerable
species richness.
Our results contradicted the previously expressed opinion that coniferous forests were
relatively poor and uniform, in terms of species number and diversity [11]. In contrast, our
results were consistent with research showing that European forests show an increase in
alpha diversity, from the species-poor north-west to the species-rich south-east of Europe [4].
Fennoscandian forests are dominated only by Scots pine and Norway spruce (a recent
colonizer) and contain a small number of shrubs, herbs, and ferns, and significantly more
moss and lichen species than vascular plants [63]. In the White Carpathians, species
richness decreases in coniferous forests [64].
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Within the investigated area, the “plant species maxima” (number of species on the
plot of 100 m2 and 1000 m2 , according to Wilson [65]) were found in the unmanaged
(natural) relict forests of Serbian spruce on Tara Mountain (71 on 100 m2 ) and Zvijezda
Mountain (125 on 1000 m2 ). These results were consistent with the established general
pattern that the alpha diversity of coniferous forests in Europe is highest in the mountains of
central and south-eastern Europe (Calcareous Alps and adjacent north-western Dinarides,
the Carpathian foothills in Romania, and the Western Carpathians in Slovakia), where
the richest plots contain between 45 and 72 species [4]. However, the fact that the most
species-rich plots in the studied forests had between 70 and 125 species, and that they
were located in the refugial areas of the continental and south-eastern Dinarides, suggested
that the true centers of diversity of European coniferous forests are located south of the
line Calcareous Alps–Western Dinarides–Carpathian foothills in Romania. Although the
plant species maxima of the coniferous forests of the Central Balkans were far below the
313 species per 1000 m2 in the Colombian tropical rainforest, or the 233 taxa per 100 m2 of
the Costa Rican tropical rainforest, the floristic richness of these forests was greater than
in some supposedly species-rich areas, e.g., the southwestern Australian forests or the
Mediterranean heathland [65].
All the top hotspots for the coniferous forest species richness were in the Central
Balkans, dominated by limestone or other calcareous bedrock types, which was consistent
with the results of a study on alpha diversity of vascular plants in European forests [4],
and a study on ecological indicator values, which suggested that the vast majority of
Central European vascular plant species prefer base-rich and calcareous soils, as also
applies for the forest flora [66,67]. Our results showed that floristic richness on a noncarbonate substrate was almost half that of the richness on carbonate, with a higher number
of species inhabiting ultramafic (species maximum 76 per 1000 m2 ), rather than silicate
substrates (species maximum 33 per 1000 m2 ). All this was consistent with the results that
explained why the flora was very rich in biogeographical regions dominated by calcareous
bedrocks [66–69]
Although not measured directly, based on the geographic location and general topography of the terrain where the plots with plant species maxima were recorded (mountainous
areas with pronounced slopes, peaks, karst fields, and mountain plateaus, as well as deep
canyons and gorges), we could conclude that the most species-rich montane coniferous
forests of the Central Balkans often grew on shallow soil and in rugged terrain, which was
also consistent with patterns whereby more rugged terrain tends to harbor more speciesrich forests than flat or gently undulating landscapes [4]. Terrain roughness influences
increasing species richness in several ways. The most important are habitat heterogeneity
and spatial mass effects [70], locally buffered climate change and associated refugial effects
during periods of macroclimatic variability [71] and poor accessibility. The low management intensity and high stand age of mountain forests favor vascular plant richness in the
understory (68).
The analyses at the forest types level I (Level I) showed that species richness (1212 taxa)
for all taxa and endemics were higher in the dark spruce forest types (Vaccinio-Piceetea),
while the percentage of endemic taxa (19%) and species density (logS/logA index) of 0.512
was higher in the light pine forest types (Erico-Pinetea) (Tables 2 and S2). These values of
species density were lower compared to the values of species density of the total number
of vascular plants for individual European countries with a similar geographic position
as the Balkan Peninsula, such as Spain (0.723) or Italy (0.684), which are areas with the
greatest species richness in Europe [6], but higher in comparison with the species density
for the same forest types only in the territory of Serbia, which has dark spruce forests 0.301
and light pine forests 0.335 [19]. Comparing the total number of species recorded in the
coniferous forests of the Balkan Peninsula (1212 taxa in dark spruce forests and 861 taxa
in light pine forests) with the number of species for the dark spruce forests in Serbia (703)
and light pine forests (683) [19], it could be seen that there were regional variations in the
species composition of the coniferous forests of the Balkan Peninsula. Similarly, the total
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number of endemic species recorded in the coniferous forests of the study area (dark spruce
forests, 188, vs. light pine forests, 162) was higher than the number of endemics recorded
in the same habitat types in Serbia (dark spruce forests, 100, vs. light pine forests, 125) [40].
The light pine forests in the Balkan Peninsula, with a percentage of 19% endemic taxa,
had among the higher values within the mountain ranges in the Mediterranean region,
where the endemism rate ranged from 10.2% in the Pindus Mountains in Greece to 28.18%
on the Baetic Mountains in Spain [72]. Furthermore, the light pine forest types on the
Balkan Peninsula and some other vegetation types (such as those of the classes Asplenietea
trichomanes, Festuco-Brometea, etc.) were the richest in Balkan endemic taxa at specific and
subspecific ranks in central Serbia and Kosovo and Metochia regions [40]. The estimated
number of endemics in other massive European mountain systems showed that 7% of the
flora was endemic to the Alps, 5% to the Pyrenees, 6% to the montane flora of Crimea [73],
and 12% to the Carpathians [74].
The high percentage of endemic taxa in montane coniferous forests could be considered
a natural consequence of the role of mountains as centers of speciation [75]. Moreover,
calcareous mountains, in areas such as the Alps or the Iberian Peninsula, were richer in
endemic species than acidic areas [76,77], and the karst of the Dinaric Mountains was the
most extensive example of a calcareous mountain in Europe. In addition, the relatively
weak and localized glaciation during the Pleistocene climate fluctuations [78,79] provided
suitable environmental conditions for the long-term survival of various species and lineages,
contributing to the high species diversity and endemism.
The analyses at the forest types level II (Level II) showed that Norway spruce forests
(Vaccinio-Piceion), with 905, and Scots pine forests (Pinion sylvestris), with 807, recorded taxa
that significantly stood out with more taxa than other forest types. Norway spruce forests
are widespread throughout the Balkan Peninsula in a variety of edaphic factors and different
habitats [11], both as zonal and secondary character forests [80], such as the widely planted
forests in Croatia during the 19th century [81] or the diverse relict communities associated
with edaphic factors and water conditions on the Kopaonik Mountain in Serbia [27]. The
widest distribution and, thus, the greatest heterogeneity of environmental conditions
certainly had a decisive influence on species richness in Norway spruce forests. Scots pine
forests showed similar distribution and heterogeneity of habitats, so this could explain
the high richness of species recorded in them. In contrast, the Serbian spruce forests
(Piceion omorikae, 246) and Macedonian pine forests (Pinion peucis, 282) had significantly
fewer taxa than the other forest subtypes (Tables 2 and S2). These two forest subtypes
covered the smallest areas in the study area and had the most uniform environmental
habitat conditions, which could be the reason why their species richness was significantly
lower compared to Norway spruce and Scots pine forests. Moreover, Macedonian pine
forests are located in the southernmost areas of zonal boreo-montane coniferous forests, and,
specifically, in the drier parts that lie between temperate continental and Mediterranean
mountain climates. Unlike Macedonian pine, Norway spruce is sensitive to summer
drought, resulting in an unfavorable water regime that makes survival impossible for
many species [11]. Serbian spruce is a poor competitor and inhabits extreme sites, such
as cliffs and peat bogs [11,82], where only a few species can survive. Moreover, Serbian
spruce forests are very localized, do not occupy large areas, and are severely degraded
by anthropogenic factors and forest fires [83]. At the same time, Macedonian pine forests
had one of the highest percentages of endemic taxa (18%) and the lowest logS/logA index
(0.442), indicating the exceptional biogeographic importance of these forests.
In comparison, Serbian spruce forests had the lowest percentage of endemic taxa
(9%) and the highest logS/logA index (0.544). This ratio was consistent with Peñas’s
pattern for endemism in Mediterranean mountains, where low species richness is followed
by a high percentage of endemics and vice versa [73]. However, Bosnian pine forests
(Pinion heldreichii) were an exception to this observation. These forests had the highest
percentage of endemic taxa (20%) and, at the same time, a high number of all taxa (579)
and endemic taxa (114).
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Table 2. Relevé and formation data and diversity parameters for all three levels of research.
Abbreviations: S—number of taxa; logS/logA—species density index; S End—number of endemic taxa. Vacc Pic Din—Vaccinio-Piceion in Dinarides; Vacc Pic ScPind—Vaccinio-Piceion in
Scardo-Pindic mountains; Vacc Pic Rhod—Vaccinio-Piceion in Rhodope mountains; Vacc Pic
Balk—Vaccinio-Piceion in Balkan mountains; Pic omor Din—Piceion omorikae in Dinarides; Pin
syl Din—Pinion sylvestris in Dinarides; Pin syl Rhod—Pinion sylvestris in Rhodope mountains;
Pin syl Balk—Pinion sylvestris in Balkan mountains; Pin peuc Din—Pinion peucis in Dinarides;
Pin peuc ScPind—Pinion peucis in Scardo-Pindic mountains; Pin peuc Rhod—Pinion peucis in
Rhodope mountains; Pin peuc Balk—Pinion peucis in Balkan mountains; Orn Eric Din—Orno-Ericion
in Dinarides; Pin heldr Din—Pinion heldreichii in Dinarides; Pin heldr ScPind—Pinion heldreichii in
Scardo-Pindic mountains; Pin heldr Rhod—Pinion heldreichii in Rhodope mountains.
Level I
No. Relevés
Relevé Area
(m2 )
S
Logs/Loga
S End
% End
Vaccinio-Piceeetea
1499
1,601,977
1212
0.497
188
16
Erico-Pinetea
431
545,314
861
0.512
162
19
Level II
No. Relevés
Relevé area
(m2 )
S
logS/logA
S End
% End
Vaccinio-Piceion
944
768,955
905
0.502
115
13%
Piceion omorikae
59
24,854
246
0.544
21
9%
Pinion sylvestris
348
463,215
807
0.513
108
13%
Pinion peucis
148
344,954
282
0.442
50
18%
Orno-Ericion
219
239,633
531
0.507
69
13%
Pinion heldreichii
212
305,681
579
0.504
114
20%
Level III
No. Relevés
Relevé area
(m2 )
S
logS/logA
S End
% End
Vacc Pic Din
758
617,444
841
0.505
89
11
Vacc Pic ScPind
26
21,179
121
0.481
14
12
Vacc Pic Rhod
124
101,007
194
0.457
19
10
Vacc Pic Balk
36
29,325
177
0.503
13
7
Pic omor Din
59
24,854
246
0.544
21
9
Pin syl Din
261
347,411
686
0.512
76
11
Pin syl Rhod
82
109,148
320
0.497
42
13
Pin syl Balk
5
6655
62
0.469
2
3
Pin peuc Din
21
48,946
114
0.439
13
11
Pin peuc ScPind
11
25,638
146
0.491
28
19
Pin peuc Rhod
95
221,423
129
0.395
15
12
Pin peuc Balk
21
48,946
79
0.405
11
14
Orn Eric Din
219
239,633
531
0.507
69
13
Pin heldr Din
114
164,376
433
0.505
77
18
Pin heldr ScPind
15
21,628
140
0.495
20
14
Pin heldr Rhod
83
119,677
236
0.467
39
17
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Bosnian pine is a heliophyte and xerophyte species [84], which makes these forests
open and light, enabling the development of herbaceous and shrub layers. Bosnian pine
forms azonal communities [11] and also forms a wide range of other different communities,
such as mixed and transitional, with other community types, inhabiting rocky substrates,
forests, mountains above the sea, and sites deeper inland [85–89]. A variety of environmental conditions, as well as a relict character of the species and the communities themselves,
could also be the reason for the extraordinary species richness in Bosnian pine forests.
The ultramafic pine forests (Orno-Ericion) also had an increased number of all taxa
(531) but had the lowest percentage of endemics (13%). These azonal pine forests occupy
unique habitats with extreme soil–microclimate relationships, such as ultramafic soils. They
are relict forests with an open canopy that allows the growth of the lower plant layers [11].
At the regional level (Level III), the highest species richness was recorded in the
Norway spruce (Vacc Pic Din. 841) and Scots pine (Pin syl Din, 686) forests of the Dinaric
mountain system, while the lowest number of species was recorded in the Scots pine forests
(Pin syl Balk, 62) and Macedonian pine forests (Pin peuc Balk, 79) of the Balkan mountain
range (Tables 2 and S2). There was a significant disparity between the data collected in this
research for the alpha diversity of Norway spruce forests in the different mountain systems.
One possible reason for this could be the difference in the scope of the surveys conducted
and the data availability. There are conflicting opinions in the relevant bibliographic data.
Some refer to the uniformity of the Norway spruce forests of south-eastern Europe with
those in Central Europe, the Alps, and Fennoscandia [11,82]. In contrast, others claim that
the nemoral montane coniferous forests harbor a whole range of autochthonous temperate
and sub-meridional mountain plants that do not occur in the boreal regions and the east
European lowlands [13]. Therefore, we propose a further and more detailed study of the
floristic diversity and differentiation of Norway spruce forests in south-eastern Europe.
The highest species density (LogS/LogA) was found in the Serbian spruce forests
(Pic omor Din, 0.544) and Scots pine forests (Pin syl Din, 0.512) of the Dinarides, while the
lowest was found in the Macedonian pine forests (Pin peuc Rod, 0.395) of the Rhodope
mountain system (Tables 2 and S2). Finally, the highest percentage of endemic taxa was
found in the Macedonian pine forests of Scardo-Pindic (Pin peuc ScPind, 19%) and the
Bosnian pine forests (Pin-heldr Din, 18%) of the Dinaric mountains, while the lowest
percentage of endemic taxa was found in the Scots pine forests (Pin syl Balk, 3%) of the
Balkan Mountains.
3.2. Centers of Floristic Richness
In our study, the primary center of the floristic richness of coniferous forests was located
in the western-central part of the Balkan Peninsula, within the following 50 × 50 MGRS
squares: CP3 (507), DN1 (419), and CP4 (402) (Figure 2, Table S3), while the secondary
centers of richness were located in the same part of the Balkan Peninsula, in the squares:
DP2 (357), XK2 (347), DN3 (337), CP1 (336), DN2 (323). As expected, the lowest number
of species was recorded in the MGRS squares on the south-eastern (GL1—17, LG2—20),
eastern (LH2—46), and south-western (CN2—20, BN3—38, BN4—44) borders of the study
area (Figure 2).
Concerning the mountain systems (Figure 3a), the incomparably greatest number of
species was recorded in the Dinaric Mountains (1273) and the least in the Balkan Mountains
(240) and the Scardo-Pindic Mountains (277). Regarding the individual mountain groups,
the most species-rich groups were also within the Dinaric system. The mountains of the
Tara group (853) had the highest number of taxa, followed by the mountain groups of
Bjelašnica (453) and Kopaonik (412). The lowest number of taxa was recorded in the
mountains of the Orjen group (44), western Stara Planina group (74), Suva Planina group
(89), Pelister 102, and western Rhodopes 105 (Figure 3b).
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Figure 2. Centers of the floristic richness of coniferous forests in the Balkan Peninsula—number of
taxa recorded within 50 × 50 MGRS squares.
Figure 3. Number of species by mountain systems (a) and mountain groups (b).
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Compared to previous findings on centers of various aspects of floristic diversity
in the Balkan Peninsula, our results look quite different at first glance. Namely, a few
comparative studies dealing with the distribution and diversity centers of the total flora [6],
Balkan endemics [30,32,36,40,44], Orophytic [7], Arctic-Alpine [37], and Boreo-Montane
plants [43], showed that the highest mountains of the central part of the Balkan Peninsula,
with altitudes exceeding 2000 m, such as Prokletije, Durmitor, Šar planina, Korab, Koritnik,
Paštrik, Kopaonik, Stara planina, Rila, Pirin, etc., represented the primary centers of floristic
diversity. The same studies showrf that mountains of medium altitude (between 1000 and
2000 m a.s.l.), such as Tara, Zlatibor, Besna Kobila, Strešer, etc., were secondary centers of
floristic diversity.
The finding that the primary centers of the floristic diversity of coniferous forests
were in the mountains having medium altitude (between 1000 and 2000 m a.s.l.) in the
area of the central and the continental Dinarides was consistent with the general ecology,
distribution, and diversity of coniferous forests in the study area. In fact, in the area of
the Tara mountain group, which includes Tara, Zvijezda, Zlatibor, Zlatar, Golija, Pobijenik,
Jadovnik, Ozren, and the Pešterska visoravan plateau, there were the largest areas of wellpreserved boreo-montane and relict oroclimatic forests, as well as the greatest diversity
of environmental conditions, which was reflected in the presence of different variants of
Norway spruce forests (Vaccinio-Piceion), Scots pine forests (Pinion sylvestris), Serbian spruce
forests (Piceion omorikae), ultramafic black pine forests (Orno-Ericion), and small fragments
of Bosnian pine forests (Pinion heldreichii). The forests in this area developed on dolomites,
limestones, and ultramafics, on mountain slopes and plateaus, and in deep canyons. Moreover, and this is very important for coniferous forests, these forests developed in very
favorable mountainous conditions with a temperate humid climate. In addition to these
ecological reasons, undoubtedly a significantly higher number of species recorded in this
part of the study area could be associated with the considerably better research status of
coniferous forests in this part of the Balkan Peninsula.
3.3. Cenotic and Spatial Diversification
The principal coordinate analysis (PCoA) for the main forest subtypes (level II) showed
that the analyzed groups were well differentiated (Figure 4a). The highest level of specificity
was shown by the Serbian spruce forests (Piceion omorikae), which were located in the
positive parts of the first and second axes, and the Macedonian pine forests (Pinion peucis),
which were located in the positive part of the first axis and in the negative part of the
second axis. A high level of specificity was also shown by the Ultramafic pine forests
(Orno-Ericion), which were located in the positive part of the second axis and in the negative
part of the first axis, while the remaining three subtypes were positioned in different parts
of the quadrant bound by the negative parts of the first and second axes (Figure 4a).
The cluster analysis yielded the same relationships as the previous analysis. However,
based on the similarity index, which exceeded 50% for all pairs, it could be concluded that
all forest subtypes were well-defined floristically (Figure 4b).
Based on the obtained lists of exclusive taxa (taxa occurring in only one group and not
present in any other analyzed group), it could also be concluded that all forest subtypes
were well-defined floristically (Table 3). The highest number of exclusive taxa was recorded
in the Norway spruce forests (Vaccinio-Piceion, 221), Scots pine forests (Pinion sylvestris, 133),
and Bosnian pine forests (Pinion heldreichii, 118). In the ultramafic pine forests (Orno-Ericion),
97 exclusive taxa were recorded, while in the Macedonian pine forests (Pinion peucis) 28 taxa
were recorded, and in the Serbian spruce forests (Piceion omorikae) only six taxa were found.
The most important exclusive species for all subtypes of the analyzed forests are listed in
Table 3.
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(a)
(b)
Figure 4. (a) Principal coordinate analysis (PCoA) for forest subtypes (Level II) (b) Cluster analysis
for forest subtypes (Level II).
Table 3. Most important exclusive taxa for all subtypes of the analyzed forests in the Balkan Peninsula.
Spruce forests
(Vaccinio-Piceion)
Aconitum lycoctonum ssp. vulparia, Adenostyles glabra, Aquilegia
nigricans, Asperula taurina, Caltha palustris, Cardamine trifolia,
Cardamine waldsteinii, Chaerophyllum aromaticum, Chaerophyllum
hirsutum, Circaea lutetiana, Cirsium waldsteinii, Clematis alpina,
Coeloglossum viride, Dryopteris dilatata, Dryopteris expansa, Equisetum
sylvaticum, Festuca altissima, Homogyne sylvestris, Hypericum
umbellatum, Lamium orvala, Lathraea squamaria, Listera cordata,
Lysimachia nemorum, Melampyrum barbatum, Myosotis scorpioides,
Omphalodes verna, Petasites albus, Petasites hybridus, Phyteuma spicatum
ssp. coeruleum, Poa hybrida, Ranunculus aconitifolius, Ranunculus acris,
Ranunculus carinthiacus, Ranunculus platanifolius, Ranunculus serbicus,
Rumex alpinus, Scopolia carniolica, Senecio papposus ssp. papposus, Silene
alba, Soldanella dimoniei, Stachys dinarica, Symphytum tuberosum agg.,
Thelypteris limbosperma, Tilia platyphyllos, Trollius europaeus, Vicia
oroboides etc.
Serbian spruce forests
(Piceion omorikae)
Epipogium aphyllum, Equisetum hyemale, Euphorbia glareosa, Hierochloe
australis, Petasites kablikianus and Saxifraga tridactylites
Scots pine forests
(Pinion sylvestris)
Avenula planiculmis, Bupleurum apiculatum, Bupleurum praealtum,
Campanula phrygia, Centaurea bracteata, Cerastium fontanum ssp. vulgare,
Chrysopogon gryllus, Cirsium grecescui, Coronilla coronata, Coronilla
vaginalis, Chamaecytisus polytrichus, Cytisus jankae, Euphorbia serpentini,
Festuca bosniaca ssp. pirinensis, Festuca spadicea, Genista carinalis, Inula
hirta, Laburnum anagyroides, Lathyrus alpestris, Linum serbicum,
Narcissus radiiflorus, Orchis morio, Pedicularis comosa, Poa stiriaca,
Potentilla regisborisii, Potentilla rupestris, Primula elatior, Quercus robur,
Ranunculus pseudomontanus, Sanguisorba officinalis, Saxifraga blavii,
Scleranthus perennis ssp. dichotomus, Stachys betonica, Stellaria palustris,
Thlaspi ochroleucum, Veronica vindobonensis, Vicia cassubica etc.
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Table 3. Cont.
Macedonian pine forests
(Pinion peucis)
Aconitum burnatii ssp. pentheri, Campanula lanata, Crataegus orientalis,
Crocus atticus, Festuca balcanica, Gentiana punctata, Geum reptans,
Helleborus cyclophyllus, Jasione orbiculata, Knautia magnifica, Luzula
spicata, Pedicularis friderici-augusti, Rhododendron ferrugineum, Senecio
abrotanifolius ssp. carpathicus, Soldanella carpatica, Stachys tymphaea,
Tozzia alpina, Viola orphanidis etc.
Ultramafic pine forests
(Orno-Ericion)
Acinos hungaricus, Aristolochia pallida, Artemisia alba, Asplenium
adulterinum, Astragalus onobrychis, Bupleurum ranunculoides,
Calamagrostis villosa, Calamintha menthifolia, Capsella bursa-pastoris,
Cardamine amara, Cardamine plumieri, Centaurea epapposa, Centaurea
reichenbachii, Centaurea scabiosa ssp. spinulosa, Chamaecytisus austriacus,
Chamaecytisus ciliatus, Chamaecytisus supinus, Cota tinctoria, Cytisus
haeufelii, Dianthus sylvestris, Doronicum grandiflorum, Euphorbia
glabriflora, Euphorbia gregersenii, Euphorbia montenegrina, Euphorbia
virgata, Festuca rupicola, Fumana procumbens, Galium flavescens,
Haplophyllum boissieranum, Isatis praecox, Lathyrus bauhinii, Linaria
rubioides, Medicago falcata, Medicago prostrata, Ornithogalum umbellatum,
Pedicularis brachyodonta, Peucedanum carvifolia, Phleum hirsutum,
Phleum montanum, Phleum phleoides, Platanthera chlorantha, Poa chaixii,
Podospermum laciniatum, Scleranthus perennis, Silene paradoxa, Stachys
recta ssp. baldaccii, Thesium divaricatum, Thymus glabrescens, Tragopogon
balcanicus, Viola beckiana etc.
Bosnian pine forests
(Pinion heldreichii)
Alchemilla glaucescens, Amphoricarpos neumayeri, Anthyllis vulneraria
ssp. alpestris, Arabis sudetica, Aster alpinus, Bornmuellera dieckii,
Campanula hercegovina, Carlina biebersteinii, Centaurea achtarovii, Crepis
dinarica, Draba lasiocarpa, Edraianthus tenuifolius, Festuca penzesii,
Genista subcapitata, Gentiana clusii, Helleborus purpurascens, Iberis
sempervirens, Leucanthemum chloroticum, Moltkia petraea, Poa
macedonica, Poa media, Potentilla clusiana, Potentilla crantzii, Rhinanthus
wagneri, Scabiosa graminifolia, Seseli kochii, Silene fabarioides, Thesium
auriculatum etc.
Such differentiation of the studied forests was generally consistent with the formal
phytocoenological classification of these phytocoenoses, which are defined as syntaxa at
the level of alliances: Piceion excelsae Pawłowski et al., 1928 and Abieti-Piceion (Br.-Bl. in
Br.-Bl. et al., 1939) Soó 1964, Dicrano-Pinion sylvestris (Libbert 1933) W. Matuszkiewicz
1962, Pinion peucis Horvat 1950, Erico carneae-Piceion omorikae Mucina et Čarni 2016, Pinion
heldreichii Horvat 1946 and Erico-Fraxinion orni Horvat 1959 [12]. However, the relationships
between the analyzed forests identified in our analyses did not correspond to the higher
classification proposed in the most recent hierarchical floristic classification system of the
Vegetation of Europe, proposed by Mucina et al. [12]. First of all, our operational units
Piceion omorikae, Pinion heldreichii, and Orno-Ericion, classified according to Mucina et al. [12]
in the common order Erico-Pinetalia Horvat 1959, class Erico-Pinetea Horvat 1959, occupied
very distant places in PCoA space (Figure 4a), indicating very important differences in
their floristic composition. Similarly, the very isolated position of our operational unit
Pinion peucis in relation to the unit Vaccinio-Piceion with which it is classified in the common
order Piceetalia excelsae Pawłowski et al., 1928 of Vaccinio-Piceetea class Bl. in Br.-Bl. et al.,
1939 [12] indicated a very specific floristic composition of the forests of the Macedonian
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pine. Finally, the grouping of our operational units Pinion heldreichii, Vaccinio-Piceion, and
Pinion sylvestris in a common quadrant in the PCoA diagram (Figure 4a) and a common
cluster in the cluster diagram (Figure 4b), indicatedthat these three units were floristically
most similar to each other, suggesting that their floristic relationships were not consistent with their formal syntaxonomic classification into two classes, Erico-Pinetea (Pinion
heldreichii) and Vaccinio-Piceetea (Vaccinio-Piceion, Pinion sylvestris).
This considerable discrepancy between the established floristic relationships and
the formal phytosociological classification at the highest hierarchical levels is almost certainly a consequence of the methodological approach to the syntaxonomic classification
of vegetation. Namely, while our floristic analysis gave equal importance to all recorded
species, phytosociological analyses attach particular importance to dominant, constant,
and, especially, diagnostic species, so the differences noted are indeed due to different
methodological approaches (floristic vs. phytosociological).
The principal coordinate analysis (PCoA) for forest subtypes at the regional level
(Level III) revealed three main geographic groups (Figure 5a). The first group consisted of
the Scots pine forests of the Balkan mountain system (Ps_B), which were clearly different
from all other groups. The second group was located in the positive part of the first
axis. It consisted of all forest types of the Dinarides, except the Macedonian pine forests
(Pin_peuc_Din), which were located in the third group that included all forest types of
the Scardo-Pindic, Rhodope, and Balkan mountain systems. Within the third group, a fine
substructure could be observed, in which the forests of the Rhodope system stood out as a
particular subunit (Figure 5a).
The cluster analysis revealed similar relationships to those identified in the PCoA analysis (Figure 5b). Namely, the cluster analysis identified three main groups of forest subtypes:
(I) Scots pine forests of the Balkan mountains (Pin_syl_Balk); (II) Dinaric Scots pine forests
(Pinion sylvestris—Pin_syl_Din), Norway spruce forests (Vaccinio-Piceion—Vacc_Pic_Din),
Bosnian pine forests (Pinion heldreichii—Pin-heldr_Din) and ultramafic black pine forests
(Orno-Ericion—Orn_Eric_Din), and (III) Other forest types of the Scardo-Pindic, Rhodope
and Balkan mountain systems, which included the Dinaric forests of Serbian spruce (Piceion
omorikae—Pic_omor_Din) and Macedonian pine (Pinion peucis—Pin_peuc_Din). Within
the last group, the forests of the Rhodope system formed a separate subgroup (Figure 4b).
The difference with regard to the results of the PCoA analysis was reflected only in the
position of the Macedonian pine forests from the Dinaric mountains, which were found in
the cluster analysis in the third mixed group, which included forests from the mountains of
the southern and eastern Balkans.
As in the cluster analysis at level II, the similarity index at the regional level (level III)
was above 50% for all pairs, confirming the previous conclusion that all forest subtypes
were well-defined floristically (Figure 5b).
The obtained relationships between the analyzed forests at the regional level (Level III)
showed an even greater discrepancy compared to the formal higher classification proposed
in the latest hierarchical floristic classification system of the Vegetation of Europe, proposed
by Mucina et al. [12]. Namely, these results showed that floristically homogeneous groups,
with minor exceptions, formed distinct forest types that developed on the same mountain
systems. This meant that the same forest types on different mountain systems differed
from each other compared to other forest types located on the same mountain system. This
result indicated that in the formation of the floristic composition of the studied coniferous
forests, the geographical factor, namely, spatial distance, had a greater influence than any
ecological differences that affected the formation of different phytocoenoses.
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Figure 5. (a) Principal coordinates analysis (PCoA) for forest sub-types at the regional level (Level III)
(b) Cluster analysis for forest sub-types at the regional level (Level III). VP D—Vaccinio-Piceion in
Dinarides; VP S—Vaccinio-Piceion in Scardo-Pindic mountains; VP R—Vaccinio-Piceion in Rhodope
mountains; VP B—Vaccinio-Piceion in Balkan mountains; Po D—Piceion omorikae in Dinarides;
Ps D—Pinion sylvestris in Dinarides; Ps R—Pinion sylvestris in Rhodope mountains; Ps B—Pinion
sylvestris in Balkan mountains; Pp D—Pinion peucis in Dinarides; Pp S—Pinion peucis in Scardo-Pindic
mountains; Pp R—Pinion peucis in Rhodope mountains; Pp B—Pinion peucis in Balkan mountains;
OE D—Orno-Ericion in Dinarides; Ph D—Pinion heldreichii in Dinarides; Ph S—Pinion heldreichii in
Scardo-Pindic mountains; Ph R—Pinion heldreichii in Rhodope mountains.
3.4. Chorological Spectrum
The chorological analysis of the total flora of the mountain coniferous forests of the
central part of the Balkan Peninsula showed that, despite the differences observed, the
dark spruce forest types (Vaccinio-Piceetea) and the light pine forest types (Erico-Pinetea)
had almost identical horological structures (Figure 6a), characterized by a marked dominance of the Eurasian (EURAS), Eurasian mountain (EAM) and Central European (CE)
chorological groups, which together accounted for over 75% of the total horological spectrum. Minor differences were found in the relationships among the main horological
groups. For example, the dark spruce forest types (Vaccinio-Piceetea) were dominated
by the Eurasian chorological group (EURAS—362 taxa; 30.04%), while the light pine forest types (Erico-Pinetea) were dominated by the Eurasian mountain chorological group
(EAM—266 taxa; 31.11%). The Central European chorological group (CE) had a slightly
higher proportion of the chorological spectrum in dark spruce forests (CE—213 taxa;
17.68%) compared to light pine forests (CE—128 taxa; 14.97%). On the contrary, a relatively
low number of elements from the northern regions was registered in both basic forest
types (Boreal—BOR—VP = 5.48% vs. EP = 4.80%, Arctic-Alpine—AA—VP = 1.99% vs.
EP = 1.99%), as well as a relatively high number of elements from the southern regions in
these mountain forests (Mediterranean–Sub-Mediterranean—MED-SUBM—VP = 8.22% vs.
EP = 10.29%).
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Figure 6. Chorological spectrum: (a) total flora of forest types (Level I), (b) total flora of forest
subtypes (Level II); (c) endemics of forest types (Level I), (d) endemics forest sub-types (Level II).
The analyses at level II showed that all forest subtypes shared the same basic chorological structure registered at level I (Figure 6b). To be specific, the overview of the chorological
groups showed that the Eurasian (EURAS) and the Eurasian mountain (EAM) chorological
groups dominated in all chorological spectra and that the Central European (CE) chorological group ranked third in terms of the number of species. However, minor variations
were observed in some forest subtypes. In particular, the proportions of Eurasian (EURAS)
and Eurasian mountain (EAM) chorological groups differed in different subtypes. Thus,
the Eurasian (EURAS) had a slightly higher proportion than the Eurasian mountain (EAM)
in most subtypes, except for the Macedonian pine forests (Pinion peucis) and the Bosnian
pine forests (Pinion heldreichii), where the Eurasian mountain chorological group (EAM)
dominated with over 33% in the spectrum. A significant deviation from the general spectrum was also registered in the Serbian spruce forests (Piceion omorikae), which had a
slightly higher number of Central European (CE 23.7%) and boreal (BOR—8.2%) chorological groups, and in the Macedonian pine forests (Pinion peucis) with boreal (BOR—8.2%)
chorological groups and the ultramafic pine forests (Orno-Ericion), where the number of
Mediterranean–Sub-Mediterranean species was significantly higher (MED-DUBM—11.5%).
The dominance of Eurasian and Eurasian-mountain chorological groups was expected,
due to the studied sites’ geographic locations and orographic characteristics. They showed
that the core of the flora in the coniferous forests in the Balkan Peninsula consisted of
Eurasian and Eurasian-mountain plants. On the other hand, the data for the Central
European chorological group pointed to solid relationships with the Central European Plain,
which could be explained by the connections between the Balkan Peninsula mountains
with the Central European Plain during the glacial periods [90].
The relatively low number of boreal (BOR) and arctic-alpine (AA) elements was mainly
explained by the fact that the studied area was located at the southern border of cold coniferous forests, which were ecologically suitable for plants of northern regions. Therefore,
most plants adapted to cold mountain habitats in the studied area belonged to the Eurasian
mountain chorological group (EAM), which included many endemic plants of the Balkan
mountains. Zupančič, in his works on spruce communities from Slovenia to Bulgaria, concluded that the number of boreal species in spruce forests decreased from the north-west
towards the south-east of the Balkan Peninsula, while Balkan species increased [91–94],
which was consistent with our results. A comprehensive study of boreo-montane flora
in selected parts of the Balkan Peninsula was conducted by Vukojičić et al. [43], who con-
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cluded that most boreal species occurred in mire vegetation, and oak and beech forests,
and to a lesser extent in coniferous forests.
The southern location of the study area, which could explain the low number of
boreal (BOR) and arctic-alpine (AA) elements, was, at the same time, the main reason for
the high proportion of the Mediterranean–Sub-Mediterranean chorological group (MEDSUBM) in the total chorological spectrum. The significant Mediterranean floristic and
florogenetic influences of the Mediterranean region on the formation of the flora of the
Balkan Peninsula, including its high mountains, are well known and well documented [7].
Moreover, the specific disproportions in the participation of boreal and Mediterranean–SubMediterranean species in coniferous forests might also be due to degradation processes
under the strong anthropogenic influences of the recent past [27].
3.5. Endemism by Vegetation Types
The analysis of the chorological characteristics of the endemic flora of the analyzed
forests (Figure 6c) showed that the two basic forest types (level I) had an almost identical chorological structure, dominated by endemic species with a broad Balkan distribution (eu-balk—VP = 5.20% vs. EP = 5.50%) and Illyrian endemics (illyr—VP = 3.14% vs.
EP = 5.0%). In addition, the Moesian endemics (moes—VP = 1.32% vs. EP= 2.31%) and
the Balkan–Carpathian sub-endemics (balk-carp—VP = 2.15% vs. EP = 2.7%) were also
represented by a significant proportion. This complex structure of the chorology of endemics showed a transitional phytogeographic character corresponding to the geographic
position of the studied mountains. It also indicated the floristic influence of the Carpathians,
which could be explained by the processes of florogenesis in the Diluvium period [7]. As
expected, Balkan–Anatolian (balk-anatol VP = 0.50% vs. EP = 0.50%) and Balkan–Pontic
sub-endemics (balk-pont VP = 0.41% vs. EP = 0.50%) had a small contribution to these
forests. This analysis also revealed nuanced differences in endemic plant structure between
dark spruce (Vaccinio-Piceetea) and light pine (Erico-Pinetea) forest types, in that, the proportion of Illyrian and Moesian endemics was significantly higher in the light pine forest
types. This indicated significant floristic influences from both provinces and defined the
light pine forests as transitional vegetation types.
The analyses of endemism at level II (Figure 6d) showed that all forest subtypes
were dominated by endemics with broad Balkan distribution (EU-balk—3.7% to 7.1%).
Significant deviations from the general spectrum of endemics were shown only in Serbian spruce forests (Piceion omorikae), characterized by the complete absence of Moesian
endemics and with the number of Balkan–Alpine sub-endemics being higher than that of
Balkan–Carpathian sub-endemics (1.2% vs. 0.4%). Macedonian pine forests (Pinion peucis)
were characterized by a higher proportion of Moesian compared to Illyrian endemics (2.8%
vs. 1.1%), which was expected, due to the geographical location of Macedonian pine forest
distribution.
3.6. Life Form Spectrum
The life form analysis revealed the absolute dominance of hemicryptophytes for both
basic forest types (Figure 7a). The dark spruce forests (Vaccinio-Piceetea) had 56% hemicryptophytes and the light pine forests (Erico-Pinetea) had 65.1%. In contrast, scandentophytes
(S) had an absolutely minimal value with less than 1% participation in the life form spectra
of both forest types. Therophytes also had a low proportion in these forests (T—VP = 6.5%
vs. EP= 5.0%), while the proportion of other life forms (P, Ch, G) varied by forest type. For
example, geophytes (G) were the second most abundant life form in dark spruce forests
with 13.8%. A similar proportion of geophytes was found in other forest types in Serbia [95].
In light pine forests, chamaephytes (Ch) accounted for 12.5%, which might indicate a high
presence of xherotherm species [96]. There were also differences in tree life forms (P),
which accounted for 11.1% in dark spruce forests and 8.5% in light pine forests (Figure 7a),
which might be related to the degradation of light pine forests under strong anthropogenic
negative influence [96].
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The dominance of hemicryptophytes applied to all forest subtypes, from 42.9% in
Serbian spruce forests (Piceion omorikae) to 58.5% in Macedonian pine forests (Pinion peucis)
(Figure 7b). Serbian spruce forests differed from the other subtypes in the high proportion
of phanerophytes, which were the next dominant with 21.6%, which was expected, since
Serbian spruce mainly formed mixed, poly-dominant relict forests [95,97]. In the other
forest subtypes, the life spectra were similar to those revealed in the analyses at level I.
In general, the life form spectrum of the mountain coniferous forests of the central
Balkan Peninsula, with a predominance of hemicryptophytes and chamaephytes and low
proportions of annuals and geophytes, was most similar to life form spectra of the Greek
endemic plants [22], Balkan endemics in Bulgaria [32], and the Balkan endemic plants in
central Serbia, and Kosovo and Metochia regions [40]. Here, it is important to emphasize
that a large part of the analyzed endemic flora consisted of high-mountain plants, so we
could speak of a specific high-mountain spectrum of life forms [40]. At the same time, the
obtained life form spectra in mountain coniferous forests followed the general trends for
the total flora of Serbia [95] and the Balkan Peninsula [98].
Figure 7. Life form spectrum of (a) forest types (Level I), (b) forest subtypes (Level II).
Hemicryptophytes (H), Therophytes (T), Geophytes (G), Phanerophytes (P), Scandentophytes (S),
Chamaephytes (Ch).
3.7. Conservation Value of Montane Coniferous Forests of the Central Balkan Peninsula
The main results of our research, showing that the mountain coniferous forests of
the central Balkan Peninsula represent a unique biogeographical phenomenon in terms
of floristic diversity, confirmed the well-known fact that coniferous forests generally have
exceptional importance for biodiversity conservation. The importance of these forests for
biodiversity conservation is primarily reflected in the fact that they represent one of the
most important habitat types in ecological terms, hosting a large part of regional and global
biodiversity [4,99].
In the Balkan Peninsula, the Habitats Directive of the European Union, as the main
legislative instrument in the field of nature conservation [17], recognizes seven European natural coniferous habitat types: 9410 Acidophilous Picea forests of the montane
to alpine levels (Vaccinio-Piceetea), 91BA Moesian silver fir forests, 9270 Hellenic beech
forests with Abies borisii-regis, 9530 * (Sub-) Mediterranean pine forests with endemic
black pines, 9540 Mediterranean pine forests with endemic Mesogean pines, 95A0 High
oro-Mediterranean pine forests and 91R0 Dinaric dolomite Scots pine forests (Genisto
januensis-Pinetum). These forest types require special measures to ensure the conservation
of a wide range of rare, threatened or endemic animal and plant species. In the mountainous area of the Balkan Peninsula, which was the subject of our study, all types of coniferous
forests of importance for the European Union were present, except Mediterranean pine
forests with endemic Mesogean pines (9540) and Sub-Mediterranean pine forests with
endemic black pines (9530).
Apart from the fact that these forests represent habitats that require special protection
measures, the numerous species that build them also require special measures related to
their populations. Among the species important for protection, the endemics, relicts and
protected species stand out.
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In our study, the presence of 219 endemic species and subspecies was registered
in the mountain coniferous forests of the central Balkans, such as Aconitum bosniacum,
Alyssum markgrafii, Alyssum pirinicum, Amphoricarpos neumayeri, Aquilegia aurea, Aquilegia
dinarica, Arabis croatica, Arabis ferdinandi-coburgii, Arabis scopoliana, Bornmuellera dieckii, Cardamine amara, Euphorbia gregersenii, Euphorbia montenegrina, Genista subcapitata, Haplophyllum
boissieranum, Helleborus multifidus, Helleborus multifidus ssp. serbicus, Lathyrus binatus, Leucanthemum platylepis, Lonicera caerulea, Melampyrum heraleoticum, Peucedanum oligophyllum,
Scrophularia bosniaca, Senecio thapsoides ssp. visianianus, Sesleria albicans ssp. angustifolia,
Sesleria serbica, Spiraea cana, Stachys anisochila, Verbascum durmitoreum, Verbascum glabratum
ssp. bosnense, Verbascum nicolai, Viola beckiana, etc. (Table S2). It is extremely important to
emphasize that many of the conifers, which have a key role in the structure and functioning
of the montane coniferous forests of the central Balkan Peninsula, are also Balkan endemics
or sub-endemics (Abies borisii-regis, Picea omorika, Pinus peuce, Pinus heldreichii, Pinus nigra
subsp. pallasiana), highlighting the unique conservation importance of these habitat types.
In addition, our research revealed the presence of 211 relict species in the same area,
namely 67 glacial relicts (e.g., Alchemilla glabra, Anthoxanthum alpinum, Arabis alpina, Arabis
alpina ssp. alpina, Arctostaphylos alpinus, Aster alpinus, Carex atrata, Cerastium cerastoides,
Cystopteris montana, Dryas octopetala, Epilobium anagallidifolium, Erigeron uniflorus, Gnaphalium norvegicum, Hieracium bifidum, Luzula spicata, Pedicularis verticillata, Persicaria vivipara,
Phleum alpinum, Poa alpina, Salix reticulata, Saxifraga adscendens, Saxifraga aizoides, Saxifraga
stellaris, Viola biflora); 88 boreal relicts (e.g., Adoxa moschatellina, Ajuga pyramidalis, Antennaria dioica, Arctostaphylos uva-ursi, Asplenium ruta-muraria, Asplenium viride, Avenella
flexuosa, Betula pubescens, Blechnum spicant, Caltha palustris, Carex ornithopoda, Cicerbita alpina,
Coeloglossum viride, Corallorrhiza trifida, Epilobium palustre, Epipogium aphyllum, Equisetum
hyemale, Filipendula ulmaria, Galium boreale, Geum rivale, Goodyera repens, Listera cordata,
Maianthemum bifolium, Moneses uniflora, Orthilia secunda, Parnassia palustris, Persicaria bistorta, Pyrola chlorantha, Pyrola media, Pyrola minor, Pyrola rotundifolia, Pyrola uniflora, Ribes
alpinum, Rubus saxatilis, Trollius europaeus, Vaccinium myrtillus, Vaccinium uliginosum, Vaccinium vitis-idaea) and 56 tertiary relicts (e.g., Acer intermedium, Amelanchier ovalis, Aposeris
foetida, Aremonia agrimonoides, Arnica montana, Aruncus dioicus, Asarum europaeum, Buphthalmum salicifolium, Calluna vulgaris, Convallaria majalis, Corylus colurna, Daphne alpina, Daphne
blagayana, Daphne cneorum, Daphne laureola, Daphne mezereum, Daphne oleoides, Epimedium
alpinum, Hacquetia epipactis, Hedera helix, Iberis sempervirens, Ilex aquifolium, Juglans regia,
Lathraea squamaria, Ligustrum vulgare, Monotropa hypopitys, Omphalodes verna, Paris quadrifolia, Rhododendron ferrugineum, Ruscus hypoglossum, Sanicula europaea, Scopolia carniolica,
Streptopus amplexifolius, Taxus baccata, Telekia speciosa). All this confirmed the fact that the
mountain coniferous forests of the central part of the Balkan Peninsula represent significant
centers of endemism and, at the same time, are a strong refuge for many plants of the
northern regions, which shifted their ranges to the Balkan Peninsula during the Pleistocene glaciations, as pointed out in [37,39,40,43,100,101]. The importance of the central
Balkans is also underlined by the fact that postglacial migration from its refugia was one
of the key factors shaping today’s high species richness of different forest types in the
Alps and Central Europe [68,102]. At this point it should be added that numerous data
confirm the existence of several refugia in the Balkan Peninsula (“refugia-within-refugia”
model—Gómez and Lunt 2007 [103]). Within these smaller, isolated and ecologically distinct refugia, populations not only survived and maintained their genetic diversity, but also
genetically differentiated [61,104]
Here it is important to emphasize that the glacial and boreal relicts on the Balkan
Peninsula are located at the southern limits of their distribution, which further underlines
their importance and necessity for biodiversity protection.
Finally, the great conservation importance of these conifer forests is also reflected in the
fact that they are habitats for numerous internationally important species that are protected
by key international legal documents related to nature protection. Thus, in our study, the
presence of 10 taxa from the Habitats Directive of the European Union (Arabis scopoliana,
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Arnica montana, Asplenium adulterinum, Echium russicum, Galanthus nivalis, Gentiana lutea,
Gentiana lutea ssp. symphyandra, Pulsatilla grandis, Ramonda serbica, Tozzia carpathica), 7 taxa
from Resolution No. 6 of the Bern Convention [105](Arabis scopoliana, Asplenium adulterinum,
Echium russicum, Lilium jankae, Narcissus angustifolius, Pulsatilla grandis, Tozzia carpathica)
and 29 species listed in Appendix II of the CITES Convention [106] (Cyclamen purpurascens
and 28 orchids, including very rare species, such as Coeloglossum viride, Corallorrhiza trifida,
Epipogium aphyllum, Goodyera repens, Gymnadenia odoratissima, Listera cordata, Listera ovata)
were recorded.
Apart from their undeniable importance for biodiversity protection, mountain coniferous forests of the Central Balkans, together with other forests at regional and global scales,
also play an essential role in mitigating, and adapting to, the effects of climate change, as
well as an essential function in the process of natural carbon sinks [99]. Unfortunately, past
forestry management practices in the Balkan Peninsula did not meet the need to ensure
high biodiversity in forest areas. Moreover, as part of the global forests, the Balkan forests
are now facing new increased pressure related to the effects of climate change, which has
led to extreme weather conditions (droughts, storms, fires) or more pests [99]. Therefore,
unsustainable forestry practices should be prevented or corrected, and should be based on
the EU Biodiversity Strategy for 2030 [107], and the New EU Forest Strategy for 2030 [108].
4. Conclusions
A number of 1435 taxa was recorded in the montane coniferous forests of the central
Balkan Peninsula, which represents a considerable species richness.
“Plant species maxima” were found in the unmanaged (natural) relict forests of Serbian
spruce on Tara Mountain (71 on 100 m2 ) and Zvijezda Mountain (125 on 1000 m2 ) in the
continental Dinarides.
Our findings are consistent with previously known patterns of an increase in alpha
diversity from the “species-poor” north-west to the “species-rich” south-east of Europe.
All of the top hotspots for the coniferous forest species richness are positioned in the
central Balkan Peninsula and are dominated by limestone or other calcareous bedrock
types, which is consistent with the results of the study of alpha diversity of vascular plants
in European forests.
The most species-rich montane coniferous forests of the central Balkan peninsula
often grow on shallow soil and rugged terrain, which is also consistent with the pattern
that more rugged terrain tends to harbor more species-rich forests than flat or gently
undulating landscapes.
The primary centers of the floristic diversity of coniferous forests in the central Balkan
Peninsula are located in the area of the central and continental Dinarides, suggesting that
the true centers of diversity of European coniferous forests are located south of the line
Calcareous Alps–Western Dinarides–Carpathian foothills in Romania, which used to be
considered the center of diversity of coniferous forests in Europe.
Species richness for all taxa and endemics groups is higher in the dark spruce forest types (Vaccinio-Piceetea), while the percentage of endemic taxa and species density
(logS/logA index) is higher in the light pine forest types (Erico-Pinetea).
The light pine forests in the Balkan Peninsula, with a percentage of 19% endemic taxa,
exhibited among the higher values within the mountain ranges in the Mediterranean region.
Concerning the mountain systems, the incomparably greatest number of species was
recorded in the Dinaric Mountains (1273) and the least in the Balkan Mountains (240) and
the Scardo–Pindic Mountains (277).
The analyzed groups of forests were well differentiated. The highest degree of specificity is shown by the Serbian spruce forests (Piceion omorikae) and the Macedonian pine
forests (Pinion peucis), and to a lesser extent in the ultramafic pine forests (Orno-Ericion).
In contrast, Norway spruce forests (Vaccinio-Piceion) and the Scots pine forests (Pinion
sylvestris) show the greatest similarity.
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Despite the observed differences, the dark spruce forest types (Vaccinio-Piceetea) and
the light pine forest types (Erico-Pinetea) show an almost identical chorological structure,
characterized by a marked dominance of the Eurasian (EURAS), Eurasian mountain (EAM),
and Central European (CE) chorological groups, which together account for over 75% of
the total chorological spectrum.
At the same time, a relatively low number of elements from northern regions (Boreal—BOR
and Arctic–Alpine—AA) and a relatively high number of elements from southern regions
(Mediterranean–Sub-Mediterranean—MED-SUBM) was recorded in the two basic forest
types in investigated mountain coniferous forests.
The dark spruce forest types (Vaccinio-Piceetea) and the light pine forest types (EricoPinetea) also have an almost identical life form spectrum, characterized by a predominance
of hemicryptophytes and chamaephytes and a small proportion of annuals and geophytes.
The mountain coniferous forests of the central Balkan Peninsula have exceptional importance in biodiversity conservation, since they represent the habitats of many important
species. such as endemics, relicts, and nationally and internationally protected species.
Unfortunately, previous forest management practices in the Balkan Peninsula were
not in line with the need to ensure high biodiversity in forest areas, so a significant number
of species are endangered today. Therefore, unsustainable forestry practices should be
prevented or corrected, and harmonized with the EU biodiversity strategy for 2030 and the
New EU Forest Strategy for 2030.
Supplementary Materials: The following supporting information can be downloaded at: https://
www.mdpi.com/article/10.3390/plants11233194/s1, Figures S1–S5: Distribution of plots by decades;
Table S1: List of sources from which the data for the analyses were taken; Table S2: Distribution of
endemic species and subspecies in diffferent types of mountain coniferous forests and mountain
systems of the central Balkans: Table S3: Number of taxa per 50 × 50 MGRS squares.
Author Contributions: Conceptualization, D.L. and T.I.; methodology, D.L., T.I. and N.K.; validation
D.L., N.K., S.V. and T.I.; formal analysis, D.L., N.K. and T.I.; investigation, T.I.; data curation, T.I., N.K.
and S.V.; writing—original draft preparation, T.I. and D.L.; writing—review and editing, N.K., S.V.
and D.L.; All authors have read and agreed to the published version of the manuscript.
Funding: N.K., S.V. and D.L. were funded by the Ministry of Education, Science and Technological
Development of the Republic of Serbia, grant number 451-03-68/2022-14/200178 and supported by
the Science Fund of the Republic of Serbia, grant number 7750112—Balkan biodiversity across spatial
and temporal scales—patterns and mechanisms driving vascular plant diversity (BalkBioDrivers).
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to the database being part of a Ph.D.
thesis. The database will be available after the publication of the dissertation.
Acknowledgments: The authors thank Kiril Vassilev (BAS) for contributing the data from the Balkan
Vegetation Database. The editor and two of the anonymous reviewers gave valuable comments for
the improvement of this paper and are gratefully acknowledged.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
2.
3.
Myers, N.; Mittermeier, R.A.; Mittermeier, C.G.; da Fonseca, G.A.B.; Kent, J. Biodiversity Hotspots for Conservation Priorities.
Nature 2000, 403, 853–858. [CrossRef] [PubMed]
Barthlott, W.; Mutke, J.; Rafiqpoor, M.D.; Kier, G.; Kreft, H. Global Centers of Vascular Plant Diversity. Nova Acta Leopold. Abh.
Kais. Leopold.-Carol. Dtsch. Akad. Nat. 2005, 92, 61–83.
Mutke, J.; Sommer, J.H.; Kreft, H.; Kier, G.; Barthlott, W. Vascular Plant Diversity in a Changing World: Global Centres and
Biome-Specific Patterns. In Biodiversity Hotspots: Distribution and Protection of Conservation Priority Areas; Zachos, F.E., Habel, J.C.,
Eds.; Springer: Berlin/Heidelberg, Germany, 2011; pp. 83–96. ISBN 978-3-642-20992-5.
Plants 2022, 11, 3194
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
23 of 26
Večeřa, M.; Divíšek, J.; Lenoir, J.; Jiménez-Alfaro, B.; Biurrun, I.; Knollová, I.; Agrillo, E.; Campos, J.A.; Čarni, A.; Crespo Jiménez,
G.; et al. Alpha Diversity of Vascular Plants in European Forests. J. Biogeogr. 2019, 46, 1919–1935. [CrossRef]
Horvat, I. Šumske zajednice Jugoslavije. In Šumarska Enciklopedija; Potočić, Z., Ed.; Jugoslavenski leksikografski zavod: Zagreb,
Croatia, 1963; Volume 2, pp. 560–590.
Stevanović, V.; Jovanović, S.; Lakušić, D.; Niketić, M. Diverzitet vaskularne flore Jugoslavije sa pregledom vrsta od med̄unarodnog
značaja. In Biodiverzitet Jugoslavije sa Pregledom Vrsta od Med̄unarodnog Značaja; Stevanović, V., Vasić, V., Eds.; Ecolibri & Biološki
Fakultet: Beograd, Serbia, 1995; pp. 183–217. ISBN 86-7078-004-6.
Stevanović, V. Analysis of the Central European and Mediterranean Orophytic Element on the Mountains of the W. and Central
Balkan Peninsula, with Special Reference to Endemics. Bocconea 1996, 5, 77–97.
Hewitt, G.M. Some Genetic Consequences of Ice Ages, and Their Role in Divergence and Speciation. Biol. J. Linn. Soc. 1996, 58,
247–276. [CrossRef]
Hewitt, G.M. Genetic Consequences of Climatic Oscillations in the Quaternary. Philos. Trans. R. Soc. Lond. B Biol. Sci. 2004, 359,
183–195, discussion 195. [CrossRef] [PubMed]
Schmitt, T. Molecular Biogeography of Europe: Pleistocene Cycles and Postglacial Trends. Front. Zool. 2007, 4, 11. [CrossRef]
Horvat, I.; Glavač, V.; Ellenberg, H. Vegetation Südosteuropas; Geobotanica selecta; Gustav Fischer Verlag: Jena, Germany, 1974;
ISBN 3-437-30168-3.
Mucina, L.; Bültmann, H.; Dierßen, K.; Theurillat, J.; Raus, T.; Čarni, A.; Šumberová, K.; Willner, W.; Dengler, J.; García, R.G.; et al.
Vegetation of Europe: Hierarchical Floristic Classification System of Vascular Plant, Bryophyte, Lichen, and Algal Communities.
Appl. Veg. Sci. 2016, 19, 3–264. [CrossRef]
Bohn, U. Karte der Natürlichen Vegetation Europas Maßstab 1:2.500.000; Interaktive CD-ROM, Erläuterungstext, Legende, Karten = Map
of the Natural Vegetation of Europe; Federal Agency for Nature Conservation: Bonn, Germany, 2004.
Köhl, M.; Linser, S. Status and Trends in European Forests Characterised by the Updated Pan-European Indicators for Sustainable
Forest Management. In Forest Europe, 2020: State of Europe’s Forests 2020; Ministerial Conference on the Protection of Forests in
Europe-Forest Europe; Liaison Unit Bratislava: Bratislava, Slovakia, 2020; pp. 28–214.
Janković, M.M. Fitoekologija sa Osnovama Fitocenologije i Pregledom Tipova Vegetacije na Zemlji, 6th ed.; Naučna knjiga: Beograd,
Serbia, 1990; ISBN 86-23-23039-6.
Em, H. Na južnoj granici areala smrče. Prilozi Makedonske Akademije na Naukite i Umetnostite 1986, V, 10–27.
Council Directive 92/43/EEC of 21 May 1992 on the Conservation of Natural Habitats and of Wild Fauna and Flora. Available
online: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A31992L0043 (accessed on 24 October 2022).
Stevanović, V.; Jovanović, S.; Lakušić, D. Diverzitet vegetacije Jugoslavije. In Biodiverzitet Jugoslavije sa Pregledom Vrsta od
Med̄unarodnog Značaja; Stevanović, V., Vasić, V., Eds.; Ecolibri & Biološki Fakultet: Beograd; pp. 219–241. 1995; ISBN 86-7078-004-6.
Lakušić, D. Odnos specijskog i ekosistemskog diverziteta. In Biodiverzitet na Početku Novog Milenijuma, Zbornik Radova sa Naučnog
Skupa Održanog 24. Novembra 2005; And̄elković, M., Ed.; Naučni skupovi knj. CXI, Odeljenje hemijskih i bioloških nauka, knj. 2;
SANU: Beograd, Serbia, 2005; pp. 75–104.
Brković, D.L.; Tomović, G.M.; Niketić, M.S.; Lakušić, D.V. Diversity Analysis of Serpentine and Non-Serpentine Flora–Or, Is
Serpentinite Inhabited by a Smaller Number of Species Compared to Different Rock Types? Biologia 2015, 70, 61–74. [CrossRef]
Bulić, Z.; Lakušić, D.; Stevanović, V. Comparative Analysis of the Vascular Floras of the Morača and Cijevna Canyons (Montenegro). Arch. Biol. Sci. 2008, 60, 485–492. [CrossRef]
Georghiou, K.; Delipetrou, P. Patterns and Traits of the Endemic Plants of Greece. Bot. J. Linn. Soc. 2010, 162, 130–153. [CrossRef]
Djordjević, V.; Tsiftsis, S.; LakuŠić, D.; Stevanović, V. Niche Analysis of Orchids of Serpentine and Non-Serpentine Areas:
Implications for Conservation. Plant Biosyst.-Int. J. Deal. All Asp. Plant Biol. 2014, 150, 710–719. [CrossRef]
Djordjević, V.; Tsiftsis, S.; Lakušić, D.; Jovanović, S.; Stevanović, V. Factors Affecting the Distribution and Abundance of Orchids
in Grasslands and Herbaceous Wetlands. Syst. Biodivers. 2016, 14, 355–370. [CrossRef]
Djordjević, V.; Tsiftsis, S.; Lakušić, D.; Jovanović, S.; Jakovljević, K.; Stevanović, V. Patterns of Distribution, Abundance and
Composition of Forest Terrestrial Orchids. Biodivers. Conserv. 2020, 29, 4111–4134. [CrossRef]
Jakovljević, K.; Lakušić, D.; Vukojičić, S.; Tomović, G.; Šinžar-Sekulić, J.; Stevanović, V. Richness and Diversity of Pontic Flora on
Serpentine of Serbia. Cent. Eur. J. Biol. 2011, 6, 260–274. [CrossRef]
Lakušić, D. Visokoplaninska Flora Kopaonika-Ekološko Fitogeografska Studija-Highmountain Flora of mt. Kopaonik-EcologicalPhytogeographical Study. Magisterium, Biološki Fakultet; Univerzitet u Beogradu: Beograd, Serbia, 1993.
Lakušić, D. Phytogeographical Characteristics of the High-Mountain Flora of Mt Kopaonik. Bocconea 1997, 5, 445–449.
Lakušić, D.; Niketić, M.; Stevanović, V. Floristička raznovrsnost rezervata “Kanjon Lazareve reke i Malinik”. Ekologija 1996, 31,
49–59.
Lubarda, B.; Stupar, V.; Milanović, Ð.; Stevanović, V. Chorological Characterization and Distribution of the Balkan Endemic
Vascular Flora in Bosnia and Herzegovina. Bot. Serbica 2014, 38, 167–184.
Matevski, V.; Petkovski, S.; Andonov, S.; Melovski, L.; Krstić, S. Country Study for Biodiversity of the Republic of Macedonia: (First
National Report); Ministry of Environment and Physical Planning: Skopje, North Macedonia, 2003; ISBN 978-9989-110-15-3.
Petrova, A.; Vladimirov, V. Balkan Endemics in the Bulgarian Flora. Phytol. Balcan. 2010, 16, 293–311.
Rand̄elović, V. Flora i vegetacija Vlasinske visoravni. Ph.D. Thesis, Biološki fakultet, Univerzitet u Beogradu, Beograd,
Serbia, 2002.
Plants 2022, 11, 3194
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
24 of 26
Stevanović, V.; Jovanović, S.; Lakušić, D.; Niketić, M. Characteristics of the Flora of Serbia and Its Phytogeographical Division. In
The Red Data Book of the Flora of SERBIA; Extinct and Critically Endangered Taxa; Stevanović, V., Ed.; Ministry of Environment of
the Republic of Serbia, Faculty of Biology, University of Belgrade, Instution for Protection of Nature of the Republic of Serbia:
Belgrade, Serbia, 1999; Volume 1, pp. 393–399. ISBN 86-7078-012-7.
Stevanović, V.; Kit, T.; Petrova, A. Diversity and Centres of Endemism in the Balkan Flora. In Proceedings of the Plenary Lecture
in Book of Abstracts Third International Balkan Botanical Congress “Plant Resources in the Creation of New Values”, Sarajevo,
Bosnia and Herzegovina, 18–24 May 2003; Redžić, S., Djug, S., Eds.; Faculty of Science, University of Sarajevo: Sarajevo, Bosnia
and Herzegovina, 2003; pp. 13–14.
Stevanović, V.; Tan, K.; Petrova, A. Mapping the Endemic Flora of the Balkans-A Progress Report. Bocconea 2007, 21, 131–137.
Stevanović, V.; Vukojičić, S.; Šinžar-Sekulić, J.; Lazarević, M.; Tomović, G.; Tan, K. Distribution and Diversity of Arctic-Alpine
Species in the Balkans. Plant Syst. Evol. 2009, 283, 219–235. [CrossRef]
Tan, K.; Stevanović, V.; Strid, A. Distribution and Centres of Diversity for Endemic Geophytic Monocots in the Balkans. Bocconea
2007, 21, 139–146.
Tomović, G. Fitogeografska Pripadnost, Distribucija i Centri Diverziteta Balkanske Endemične Flore u Srbiji. Ph.D. Thesis,
Biološki fakultet, Univerzitet u Beogradu: Beograd, Serbia, 2007.
Tomović, G.; Niketić, M.; Lakušić, D.; Rand̄elović, V.; Stevanović, V. Balkan Endemic Plants in Central Serbia and Kosovo Regions:
Distribution Patterns, Ecological Characteristics, and Centres of Diversity. Bot. J. Linn. Soc. 2014, 176, 173–202. [CrossRef]
Trigas, P.; Iatrou, G.; Karetsos, G. Species Diversity, Endemism and Conservation of the Family Caryophyllaceae in Greece.
Biodivers. Conserv. 2007, 16, 357–376. [CrossRef]
Velchev, V. Floral and Plant Biodiversity on Calcareous Terrains in Bulgaria. Phytol. Balc. 1998, 4, 81–92.
Vukojičić, S.; Jakovljević, K.; Matevski, V.; Randjelović, V.; Niketić, M.; Lakušić, D. Distribution, Diversity and Conservation of
Boreo-Montane Plant Species in the Central Part of the Balkan Peninsula and the Southern Part of the Pannonian Plain. Folia
Geobot. 2014, 49, 487–505. [CrossRef]
Vuksanović, S.; Tomović, G.; Niketić, M.; Stevanović, V. Balkan Endemic Vascular Plants of Montenegro—Critical Inventory with
Chorological and Life-Form Analyses. Will 2016, 46, 387–397. [CrossRef]
Zlatković, B. Flora i Fitogeografska Pripadnost Doline Reke Pčinje u Jugoistočnoj Srbiji. Ph.D. Thesis, Biološki fakultet, Univerzitet
u Beogradu, Beograd, Serbia, 2011.
Zlatković, B.; Nikolić, L.; Rand̄elović, V.; Rand̄elović, N.; Stevanović, V. Comparative Analyses of the Vascular Flora of the Pčinja
River Gorges in Serbia and Macedonia. Arch. Biol. Sci. 2011, 63, 1157–1166. [CrossRef]
Kryštufek, B.; Reed, J.M. Pattern and Process in Balkan Biodiversity—An Overview. In Balkan Biodiversity: Pattern and Process in
the European Hotspot; Griffiths, H.I., Kryštufek, B., Reed, J.M., Eds.; Springer: Dordrecht, The Netherlands, 2004; pp. 1–8. ISBN
978-1-4020-2854-0.
Reed, J.M.; Kryštufek, B.; Eastwood, W.J. The Physical Geography of The Balkans and Nomenclature of Place Names. In Balkan
Biodiversity; Springer: Dordrecht, The Netherlands, 2004; pp. 9–22.
Jax, K. Ecological Units: Definitions and Application. Q. Rev. Biol. 2015, 81, 237–258. [CrossRef]
Vassilev, K.; Pedashenko, H.; Alexandrova, A.; Tashev, A.; Ganeva, A.; Gavrilova, A.; Gradevska, A.; Assenov, A.; Vitkova, A.;
Grigorov, B.; et al. Balkan Vegetation Database: Historical Background, Current Status and Future Perspectives. Phytocoenologia
2016, 46, 89–95. [CrossRef]
Vassilev, K.; Pedashenko, H.; Alexandrova, A.; Tashev, A.; Ganeva, A.; Gavrilova, A.; Macanović, A.; Assenov, A.; Vitkova, A.;
Genova, B.; et al. Balkan Vegetation Database (BVD)–Updated Information and Current Status. Veg. Classif. Surv. 2020, 1, 151–153.
[CrossRef]
Lampinen, R. Universal Transverse Mercator (UTM) and Military Grid Reference System (MGRS). Available online: https:
//www.luomus.fi/en/utm-mgrs-atlas-florae-europaeae (accessed on 10 September 2022).
Meusel, H.; Jäger, E.; Weinert, E. Vergleichende Chorologie der Zentraleuropäischen Flora; Text und Kartenband; Gustav Fischer Verlag:
Jena, Germany, 1965; Volume 1.
Meusel, H.; Jäger, E.; Rauschert, S.; Weinert, E. Vergleichende Chorologie der Zentraleuropäischen Flora; Text und Kartenband; Gustav
Fischer Verlag: Jena, Germany, 1978; Volume 2.
Meusel, H.; Jäger, E.J. Vergleichende Chorologie der Zentraleuropäischen Flora; Text und Kartenband; Gustav Fischer Verlag: Jena,
Germany; Stuttgart, Germany; New York, NY, USA, 1992; Volume 3, ISBN 3-334-00411-2.
Stevanović, V. Floristička podela teritorije Srbije sa pregledom viših horiona i odgovarajućih flornih elemenata. In Flora Srbije;
Sarić, M.R., Ed.; SANU, Odeljenje prirodno-matematičkih nauka: Beograd, Serbia, 1992; Volume 1, pp. 47–56.
Raunkiaer, C. The Life Forms of Plants and Statistical Plant Geography; Clarendon Press: Oxford, UK, 1934.
Mueller-Dombois, D.; Ellenberg, H. Aims and Methods of Vegetation Ecology; John Wiley & Sons: New York, NY, USA, 1974;
ISBN 0-471-62290-7.
Hammer, Ø.; Harper, D.A.T.; Ryan, P.D. PAST: Paleontological Statistics Software Package for Education and Data Analysis.
Palaeontol. Electron. 2001, 4, 1–9.
ter Braak, C.J.F.; Šmilauer, P. Canoco Reference Manual and User’s Guide: Software for Ordination, Version 5.0; Microcomputer Power:
Ithaca, NY, USA, 2012.
Plants 2022, 11, 3194
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
25 of 26
Španiel, S.; Rešetnik, I. Plant Phylogeography of the Balkan Peninsula: Spatiotemporal Patterns and Processes. Plant Syst. Evol.
2022, 308, 1–31. [CrossRef]
Mutke, J.; Kreft, H.; Kier, G.; Barthlott, W. European Plant Diversity in the Global Context. In Atlas of Biodiversity Risk; Pensoft
Publishers: Sofia, Bulgaria, 2010; pp. 1–5. ISBN 978-954-642-446-4.
Esseen, P.-A.; Ehnström, B.; Ericson, L.; Sjöberg, K. Boreal Forests—The Focal Habitats of Fennoscandia. In Ecological Principles
of Nature Conservation: Application in Temperate and Boreal Environments; Conservation Ecology Series: Principles, Practices and
Management; Hansson, L., Ed.; Springer US: Boston, MA, USA, 1992; pp. 252–325. ISBN 978-1-4615-3524-9.
Otýpková, Z.; Chytrý, M.; Tichý, L.; Pechanec, V.; Jongepier, J.; Hájek, O. Floristic Diversity Patterns in the White Carpathians
Biosphere Reserve, Czech Republic. Biologia 2011, 66, 266–274. [CrossRef]
Wilson, J.B.; Peet, R.K.; Dengler, J.; Pärtel, M. Plant Species Richness: The World Records. J. Veg. Sci. 2012, 23, 796–802. [CrossRef]
Ewald, J. The Calcareous Riddle: Why Are There so Many Calciphilous Species in the Central European Flora? Folia Geobot. 2003,
38, 357–366. [CrossRef]
Ujházyová, M.; Ujházy, K.; Chytrý, M.; Willner, W.; Čiliak, M.; Máliš, F.; Slezák, M. Diversity of Beech Forest Vegetation in the
Eastern Alps, Bohemian Massif and the Western Carpathians. Preslia 2016, 88, 435–457.
Ewald, J. Plant Species Richness in Mountain Forests of the Bavarian Alps. Plant Biosyst. Int. J. Deal. All Asp. Plant Biol. 2008, 142,
594–603. [CrossRef]
Pärtel, M. Local Plant Diversity Patterns and Evolutionary History at the Regional Scale. Ecology 2002, 83, 2361–2366. [CrossRef]
Zelený, D.; Li, C.-F.; Chytrý, M. Pattern of Local Plant Species Richness along a Gradient of Landscape Topographical Heterogeneity: Result of Spatial Mass Effect or Environmental Shift? Ecography 2010, 33, 578–589. [CrossRef]
Sandel, B.; Arge, L.; Dalsgaard, B.; Davies, R.G.; Gaston, K.J.; Sutherland, W.J.; Svenning, J.-C. The Influence of Late Quaternary
Climate-Change Velocity on Species Endemism. Science 2011, 334, 660–664. [CrossRef]
Peñas, J.; Pérez-García, F.J.; Mota, J.F. Patterns of Endemic Plants and Biogeography of the Baetic High Mountains (South Spain).
Acta Bot. Gall. 2005, 152, 347–360. [CrossRef]
WWF; IUCN. Centres of Plant Diversity. A Guide and Strategy for Their Conservation; Europe, Africa, South West Asia and the
Middle East; Davis, S.D., Heywood, V.H., Hamilton, A.C., Eds.; IUCN Publications Unit: Cambridge, UK, 1994; Volume 1,
ISBN 978-2-8317-0197-4.
Favarger, C. Endemism in the Montane Floras of Europe. In Taxonomy, Phytogeography and Evolution; Valentine, D.H., Ed.;
Academic Press: London, UK, 1972; pp. 191–204. ISBN 0-12-710250-7.
Tzedakis, P.C.; Lawson, I.T.; Frogley, M.R.; Hewitt, G.M.; Preece, R.C. Buffered Tree Population Changes in a Quaternary
Refugium: Evolutionary Implications. Science 2002, 297, 2044–2047. [CrossRef] [PubMed]
Essl, F.; Staudinger, M.; Stöhr, O.; Schratt-Ehrendorfer, L.; Rabitsch, W.; Niklfeld, H. Distribution Patterns, Range Size and Niche
Breadth of Austrian Endemic Plants. Biol. Conserv. 2009, 142, 2547–2558. [CrossRef]
Dominguez Lozano, F.; Galicia Herbada, D.; Moreno Rivero, L.; Moreno Saiz, J.; Sainz Ollero, H. Areas of High Floristic Endemism
in Iberia and the Balearic Islands: An Approach to Biodiversity Conservation Using Narrow Endemics. Belg. J. Entomol. 2000, 2,
171–185.
Bognar, A.; Faivre, S.; Pavelić, J. Glaciation traces on the North Velebit. Hrvat. Geogr. Glas. 1991, 53, 27–38.
Milivojević, M.; Menković, L.; Ćalić, J. Pleistocene Glacial Relief of the Central Part of Mt. Prokletije (Albanian Alps). Quat. Int.
2008, 190, 112–122. [CrossRef]
Stefanović, V. Fitocenologija sa Pregledom šumskih Fitocenoza Jugoslavije, 2nd ed.; Svjetlost: Sarajevo, Bosnia and Herzegovina, 1986.
Alegro, A. Vegetacija Hrvatske; Interna skripta, Botanički zavod PMF-a: Zagreb, Croatia, 2000.
Prirodna Potencijalna Vegetacija Jugoslavije (Komentar Karte M 1: 1,000,000); Jovanović, B.; Jovanović, R.; Zupančič, M. (Eds.) Naučno
veće vegetacijske karte Jugoslavije: Ljubljana, Slovenia, 1986.
Čolić, D. Antropogena degradacija jedne mešovite reliktne zajednice sa Pančićevom omorikom (Picea Omorika Pančić). Zb. Rad.
Biol. Inst. Srb. 1964, 7, 1–32.
Janković, M.M. Razmatranja o uzajamnim odnosima molike (Pinus Peuce) i munike (Pinus Heldreichii), kao i o njihovim
ekološkim osobinama, posebno u odnosu na geološku podlogu. Glas. Bot. Zavoda i Bašte Univ. u Beogr. 1960, 1, 141–180.
Košanin, N. Četinari Južne Srbije. Glas. Skopskog Naučnog Društva 1925, 1, 247–261.
Fukarek, P. Prilog poznavanju dendrogeografskih i fitocenoloških odnosa planina sjeverozapadne Crne Gore. Rad. Od. Privred.-Teh.
Nauka Naučno Društvo SR Bosne Hercegovine 1963, 22, 113–166.
Fukarek, P. Zajednice endemne munike na planini Prenju u Hercegovini. Acta Bot. Croat. 1966, 25, 61–83.
Janković, M.M. Prilog poznavanju munikovih šuma (Pinetum Heldreichii) na Metohijskim Prokletijama. Arh. Biol. Nauka 1958,
10, 51–69.
Janković, M.M. Peucedano-Pinetum heldreichii M.Jank., nova asocijacija subendemičnog balkanskog bora Pinus heldreichii na
Orjenu. Glas. Bot. Zavoda Bašte Univ. Beogr. 1962, 2, 203–206.
Janković, M.M. Vegetacija SR Srbije; Istorija i opšte karakteristike. In Vegetacija SR Srbije; SANU: Beograd, Serbia, 1984; Volume 1,
Opšti deo; pp. 1–189.
Zupančič, M. Smrekovi gozdovi Evrope in Balkanskega polotoka, I. Biol. Vestn. 1980, 28, 137–158.
Zupančič, M. Smrekovi gozdovi Evrope in Balkanskega polotoka, II. Biol. Vestn. 1982, 30, 171–188.
Plants 2022, 11, 3194
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
108.
26 of 26
Zupančič, M. Illyrische und Balkanische Arten in den Subalpinen Fichtengesellschaften der zentralen Balkanhalbinsel. SauteriaSchr. Syst. Bot. Flor. Geobot. 1988, 4, 33–42.
Zupančič, M. Smrekovi gozdovi Evrope in Balkanskega polotoka, III. Biol. Vestn. 1990, 38, 5–22.
Diklić, N. Životne forme biljnih vrsta i biološki spektar Flore SR Srbije. In Vegetacija SR Srbije; SANU: Beograd, Serbia, 1984;
Volume 1, Opšti deo; pp. 291–316.
Tatić, B.; Tomić, Z. Šume crnog i belog bora. In Vegetacija Srbije; Škorić, D.M., Ed.; SANU: Beograd, Serbia, 2006; Volume 2, Šumske
zajednice (2); pp. 127–154. ISBN 86-7025-428-X.
Dinić, A.; Tatić, B. Šume Pančićeve omorike. In Vegetacija Srbije; Škorić, D.M., Ed.; SANU: Beograd, Serbia, 2006; Volume 2,
Šumske zajednice (2); pp. 213–244. ISBN 86-7025-428-X.
Turrill, W.B. The Plant-Life of the Balkan Peninsula, a Phytogeographical Study; Oxford Memoirs on Plant Geography; Clarendon Press:
Oxford, UK, 1929.
European Commission Directorate-General for Environment Forests. Available online: https://ec.europa.eu/environment/
forests/index_en.htm (accessed on 10 October 2022).
Magri, D. Patterns of Post-Glacial Spread and the Extent of Glacial Refugia of European Beech (Fagus Sylvatica). J. Biogeogr. 2008,
35, 450–463. [CrossRef]
Tzedakis, P.C.; Emerson, B.C.; Hewitt, G.M. Cryptic or Mystic? Glacial Tree Refugia in Northern Europe. Trends Ecol. Evol. 2013,
28, 696–704. [CrossRef] [PubMed]
Jiménez-Alfaro, B.; Chytrý, M.; Mucina, L.; Grace, J.B.; Rejmánek, M. Disentangling Vegetation Diversity from Climate–Energy
and Habitat Heterogeneity for Explaining Animal Geographic Patterns. Ecol. Evol. 2016, 6, 1515–1526. [CrossRef] [PubMed]
Gómez, A.; Lunt, D.H. Refugia within Refugia: Patterns of Phylogeographic Concordance in the Iberian Peninsula. In Phylogeography of Southern European Refugia; Weiss, S., Ferrand, N., Eds.; Springer: Dordrecht, Germany, 2007; pp. 155–188.
ISBN 978-94-007-0752-8. [CrossRef]
Surina, B.; Schönswetter, P.; Schneeweiss, G.M. Quaternary Range Dynamics of Ecologically Divergent Species (Edraianthus
Serpyllifolius and E. Tenuifolius, Campanulaceae) within the Balkan Refugium. J. Biogeogr. 2011, 38, 1381–1393. [CrossRef]
Council of Europe Convention on the Conservation of European Wildlife and Natural Habitats Resolution No. 6 (1998) Listing the
Species Requiring Specific Habitat Conservation Measures (Adopted by the Standing Committee on 4 December 1998). Available
online: https://rm.coe.int/1680746afc (accessed on 8 November 2022).
CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora, Appendices I, II and III. Available
online: https://cites.org/sites/default/files/eng/app/2022/E-Appendices-2022-06-22.pdf (accessed on 9 November 2022).
European Commission Directorate-General for Environment EU Biodiversity Strategy for 2030. Available online: https://
environment.ec.europa.eu/strategy/biodiversity-strategy-2030_en (accessed on 10 October 2022).
European Commission Directorate-General for Environment New EU Forest Strategy for 2030. Available online: https://
environment.ec.europa.eu/strategy/forest-strategy_en (accessed on 10 October 2022).