Aims: Lebanon is renowned in the Levant for its distinctive vegetation types with some biodiversity hotspots as Mount Hermon, with rare and endangered endemic plant species. We aim to present the ecological characteristics and spatial distribution of habitat types present on its western slopes through the analysis of plant communities. Study area: Mount Hermon, Lebanon. Methods: We surveyed 169 plots, each spanning an area of 314 m², from 2020 to 2023, in the district of Rashaya, calculated compositional dissimilarity using the Bray–Curtis index, conducted hierarchical clustering analysis using the unweighted pair group method with arithmetic mean (UPGMA), applied the Nonmetric Multidimensional Scaling (NMDS) method to investigate the relationship between species frequency per site and environmental parameters, and identified significant diagnostic species for each group. Results: We recorded 383 taxa, including 27 narrow endemics. Ten habitat types are described; three at the oro-Mediterranean level: hedgehog-heaths of Astragalus echinus and Noaea mucronata, hedgehog-heaths of Tanacetum densum and Astragalus cruentiflorus, cliffs of Rosularia sempervivum subsp. libanotica; three at the supra-Mediterranean level: grasslands with Eryngium glomeratum, woodlands of Quercus infectoria, Q. coccifera and Crataegus azarolus, evergreen woodlands of Q. coccifera; four at the montane level: scree deciduous woodlands of Prunus korshinskyi and Lonicera nummulariifolia, woodlands of deciduous P. korshinskyi and evergreen Q. coccifera, shrublands of Astragalus gummifer, and deciduous woodlands of Quercus look and Acer monspessulanum subsp. microphyllum. Four environmental variables exhibited significant influences in shaping vegetation composition: elevation, mean annual temperature, slope and northness. Conclusions: Five habitats are novelties proposed as sub-types for the national typology. Floristic affinities with Mount Barouk are highlighted. The nature reserve on the western slopes of Mount Hermon encompasses the majority of the identified habitats. The insights from this study and the habitat map are useful for the development of a management plan and conservation measures.

Taxonomic reference: International Plant Names Index (IPNI 2023).

Abbreviations: EUNIS = European Nature Information System; NMDS = nonmetric multidimensional scaling; UPGMA = unweighted pair group method with arithmetic mean; WGS84 = World Geodetic System, 1984.

cliffs, endemism, EUNIS, habitat type, hedgehog-heath, vegetation classification, Lebanese national typology, Levant, montane-Mediterranean, Prunus korshinskyi, Quercus look, oro-Mediterranean

Within the eastern Mediterranean, the Levant stands as the junction point between Europe, Africa, and Asia, where three floristic regions meet: the Saharo-Sindian region, the Mediterranean region, and the Irano-Turanian region (Takhtajan 1986). In this biogeographical crossroad, complex biodiversity patterns have emerged (Krupp et al. 2009) and are distributed among the three prominent components of the Levant: the Mediterranean region, the Syro-African Rift, and the Syrian desert. Geographic and geomorphologic features allow the demarcation between the Northern and the Southern Levants. The Northern Levant, extending from the Nur Mountains northward to Galilee southward, is characterised by its distinctive mountainous topography (Abel 1933; Vaumas 1954; Suriano 2013). Mount Lebanon, Anti-Lebanon, and Mount Hermon are located in the Northern Levant, forming the highest ranges across the entire Levant (Vaumas 1954). These ranges have been recognized as regional hotspots of biodiversity within the larger Mediterranean Basin ‘macro’ hotspot, attributed to their remarkable floristic endemism which accounts for 12% of the total flora (Médail and Quézel 1997, 1999; Myers et al. 2000; Verlaque et al. 2001; Cañadas et al. 2014). At the Lebanese national scale, these mountain ranges are of high-priority conservation value as they have been identified as Important Plant Areas (Bou Dagher-Kharrat et al. 2018) and as Key Biodiversity Areas (El Zein et al. 2018) due to the simultaneous presence of rare and endangered endemic plant species.

Lebanon is renowned for its distinctive vegetation types in the Levant. Since ancient times, dating back to 2600 years BC, its mountains have been recognized for their remarkable and iconic conifer forests, composed of cedar (Cedrus libani), fir (Abies cilicica), and juniper (Juniperus excelsa) (Vaumas 1954; Beals 1965; Mikesell 1969). Nevertheless, other types of vegetation also occur in these mountains, forming unique associations of plant species (Post and Dinsmore 1932; Mouterde 1966, 1970, 1984). Several publications have described the vegetation of Lebanon. The description of the climactic series of vegetation of Lebanon and their spatial distribution constitutes one of the greatest achievements in this discipline for the country (Abi-Saleh 1982; Abi-Saleh and Safi 1988). Complementary efforts have provided detailed information about the phytosociological associations that compose some forest types on the western slopes of the Mount Lebanon range (Chouchani et al. 1975; Barghachoun 1976; de Foucault et al. 2013; Stephan et al. 2019). Recently, a typology of the natural and semi-natural terrestrial habitat types has been developed (El Zein et al. 2022) aligned to the hierarchical structure of the habitat classification of the European Nature Information System (EUNIS) (Davies et al. 2004) to facilitate efforts for conservation across the Mediterranean Basin and in neighboring countries. Moreover, the use of an international classification system improves the recognition of local diversity and natural patrimony.

However, detailed descriptions of the plant communities for each habitat type in Lebanon still require improvement and are continuously developing. The habitat types present on the western slopes of Mount Hermon in Lebanon were partly characterised through the vegetation series (Abi-Saleh and Safi 1988). Part of the area was designated as a nature reserve in December 2020, promoting the undertaking of comprehensive studies to document and conserve the natural patrimony present. The primary objective of our study was to address this knowledge gap and comprehend the ecological characteristics and spatial distribution of vegetation types. This paper consequently proposes to characterize and map the different habitats of western Mount Hermon in Lebanon based on their plant communities.

Mount Hermon, or Jabal al-Shaykh in Arabic, is administratively divided into four parts: the Lebanese western slopes, the Syrian eastern slopes, the United Nations buffer zone where the United Nations Disengagement Observer Force (UNDOF) operates, and the Israeli-occupied southern slopes that are part of the Golan Heights (Dar 1988). It stands as the second-highest mountain in the Levant, reaching an elevation of 2,814 m a.s.l., and is often considered as the southern continuation of the Anti-Lebanon mountain range. The massif extends 25 km from west to east and 45 km from north to south . The entire range spans an area of approximately 1,000 km², with half of it located in Lebanon (Clermont-Ganneau 1903; Abel 1933).

Most of the upper stratum of Mount Hermon is dominated by Jurassic limestone (Dubertret 1955). In the mountain’s circumference, Cretaceous strata occur with occasional veins of basalt (Dubertret 1955). In most of Lebanon, the soils are young, characterized by poor consistency and shallowness, especially on sloping terrains (Clermont-Ganneau 1903; Vaumas 1954). These conditions contribute to the development of terra rossa soils (Gèze 1956). On the highest slopes, rough terrain features have been created by karstic erosion, such as crags, boulders or sinkholes. Precipitation is quickly absorbed through the porous rocky substrate and feed different watersheds. Westward and southward, the waters feed the headstreams of the Jordan River, while eastward it feeds other springs descending to the Damascus basin (Abel 1933).

Mount Hermon has a typically Mediterranean climate, with January as the coldest month, and July and August as the warmest (Abi-Saleh and Safi 1988). The annual average temperature in Rashaya, at the base of Mount Hermon at 1,200 m a.s.l., is 15.6°C (Baldy 1959). In Rachaya, the mean maximum temperature of the warmest month is 34.1°C, while the mean minimum temperature of the coldest month is 0.5°C (Baldy 1959). The mean annual rainfall in Rashaya is 675 mm (Baldy 1959), reaching around 1,500 mm at peak (YMCA Lebanon 2005; Ayalon et al. 2013). Approximately 80% of the annual rainfall takes place between November and March. The growing season spans from May to mid-September, during which the majority of plant species flower and set seed.

The western slopes of Mount Hermon, part of the Lebanese territory (Figure 1), have been recognized for their floristic diversity (Arnold et al. 2015; Baydoun and Arnold 2017) and the presence of at least 21 endangered endemic plant taxa (El Zein and Kahale 2022). The flora of the area remains relatively understudied. For instance, a species not previously reported in the flora of Lebanon was recently observed there (El Zein et al. 2023). The first checklist of the flora of western Mount Hermon (Arnold et al. 2015) highlighted the significant contribution of the region to traditional ethnobotanical knowledge held by the local communities. The prolonged historical interactions between the land and the successive communities living there have given rise to diverse traditions and cultural heritages (Dar 1993; Farra Haddad 2021). Moreover, the area constitutes a repository for wild crop relatives and a cradle for the domestication of wheat ancestors (Ghossain et al. 2023).

Figure 1. 

View on the western slopes of Mount Hermon in May 2019, Lebanon.

The floristic study conducted on the western slopes of Mount Hermon enabled the characterisation of ten habitat types, based on species differences and the influence of four significant environmental variables. Elevation and mean annual temperature emerged as the most influential factors shaping floristic composition. Although mean annual temperature and elevation exhibit a direct relationship, it is prudent to consider them separately due to the varied influences associated with them. Slope ranked as the third most significant environment variable, notably influencing floristic variation among the habitat groups of the oro-Mediterranean level. Northness also exerted a significant influence, particularly affecting the differentiation of the scree woodlands of Prunus korshinskyi from the other montane habitats.

Five habitat types represent novelties, constituting sub-types of broader habitat types described in the national typology (El Zein et al. 2022). They include the description of two types of hedgehog-heaths at the oro-Mediterreanean level. The group of Astragalus echinus and Noaea mucronata exhibits a preference for slopes and thalwegs where exposure to wind and sun is reduced, and the soils is deeper. The group of Tanacetum densum and Astragalus cruentiflorus thrives on hilltops and south-oriented slopes, showing a preference for xeric and rocky situations. Hedgehog-heaths are unique habitats and constitute relict vegetation poorly studied in the Levant, primarily composed of endemics or rare species belonging to the ancient Mediterranean Tertiary flora (Musarella et al. 2020). Both of these habitats are endemic to Mount Lebanon, Mount Hermon and Anti-Lebanon, indicated by the presence of taxa strictly endemic to these ranges. The first habitat includes Astragalus coluteoides, A. hermoneus, and A. nummularius subsp. trichopterus, while the second contains the diagnostic species A. cruentiflorus.

Another novelty is the description of a plant group diagnostic of the cliffs at the oro-Mediterranean level in western Mount Hermon. This group comprises twelve taxa, with Rosularia sempervivum subsp. libanotica having the highest diagnostic value, and the majority of them are endemic to the mountains of South Turkey, Mount Lebanon, Anti-Lebanon and Mount Hermon. We propose categorizing this habitat as a sub-type of “Mediterranean bare limestone inland cliffs” (U387) of the national habitat typology, specifically characterizing the oro-Mediterranean limestone cliffs of Mount Hermon in Lebanon. This contributes significantly to our understanding of plant communities on cliffs, as this habitat has remained poorly studied in the Levant, and oro-Mediterranean cliffs of this region were previously undocumented (Davis 1951; Wagensommer 2017).

The scree deciduous montane woodlands of Prunus korshinskyi and Lonicera nummulariifolia represent a habitat type that has been insufficiently characterised in the past. This unique habitat is distinguished by its specific substrate, notably the screes, and the distinctive aspect of the slope. The formations of P. korshinskyi show affinities with the Arabic Peninsula (Zohary 1973), while the presence of L. nummulariifolia characterises typical Eastern Mediterranean and Irano-Turanian habitats (Davis et al. 1965). At the Lebanese level, woodlands featuring P. korshinskyi are a rarity and are exclusively found on the eastern slopes of Mount Lebanon between Wadi Faara, Ainata and Yammoune in a limited area (Mouterde 1966, 1970). We propose this habitat as a sub-type of “Lebanese wild fruit trees steppe wood” of the national typology (T19B9_LB1). The second montane woodland including P. korshinskyi in association with Quercus coccifera constitutes a second sub-habitat.

Quercus look is a tree endemic to Mount Lebanon, Anti-Lebanon and Mount Hermon (Avishai 2017). The inhabitants of the region of Rachaya historically distinguished this oak species from others, assigning it the name “Look” in Arabic which later became its specific epithet (Avishai 2017). Deciduous montane woodlands of Q. look associated with Acer monspessulanum subsp. microphyllum constitute a unique habitat endemic to the region, specifically occurring in the region of Mount Hermon. Similar Q. look woodlands were also identified at the montane-Mediterranean level on the heights of Mount Barouk in Mount Lebanon (Chouchani et al. 1975; Abi-Saleh and Safi 1988). In this area, this tree species was known to form pure stands within the ecological zone of Cedrus libani, sometimes co-dominating with the latter. Nevertheless, these woodlands lacked precise documentation in earlier studies, and this research significantly contributes by providing additional insights into their floral composition. These contributions acknowledge the distinctiveness and rarity of the Q. look woodlands.

The floristic complexity of the supra-Mediterranean woodlands was highlighted, revealing two main types distinguished by elevation and the prevalence of either Quercus coccifera or Q. infectoria. However, the floristic composition did not effectively differentiate between degraded forms of these habitats. For instance, the thickets of Crataegus azarolus, representing the degraded form of the upper supra-Mediterranean woodlands of Q. infectoria, and the gradual transitions were all grouped together. This emphasizes the crucial role that physiognomy of the vegetation plays in interpreting results.

This brings to light an important parameter affecting the habitats of the western slopes of Mount Hermon, namely the impact of the historical anthropic activities that have gradually modified the physiognomy of the vegetation and thus the landscape of the area. The current landscapes of Mount Hermon are made of relict habitats compared to what they used to be (Abel 1933; Vaumas 1954; Mouterde 1966; Mikesell 1969). For example, the deciduous woodlands of Quercus look have almost disappeared and only scattered patches remain in Mount Hermon. The current pastoral activities are not allowing a decent regeneration as the seedlings are systematically grazed by goats.

Similar to many areas in the western slopes of Anti-Lebanon range, the woodlands of Juniperus excelsa have disappeared due to intense exploitation for firewood (Mouterde 1966). This was the only conifer species observed in our surveys and it was reported to have a wider distribution in the past. Usually, montane-Mediterranean belts are dominated by coniferous formations (Quézel and Barbero 1982) but it is not the case anymore in Mount Hermon. These woodlands have become rare due to past wood exploitation. The presence of J. excelsa woodlands on the western slopes of Anti-Lebanon, between 1,700 and 2,800 m a.s.l. (Vaumas 1954; Mouterde 1966), indicates that the relict woodlands present on the Lebanese slopes of Mount Hermon could have once extended over a larger area. Historical documents described Mount Hermon with significant forest cover during the antiquity (Abel 1933; Vaumas 1954; Mikesell 1969). Nevertheless, until now it still constitutes the southernmost edge of the distribution range of this conifer (Douaihy et al. 2011, 2013; Caudullo et al. 2017).

Human activities have significantly influenced the diversity at the landscape level, resulting in a characteristic mosaic of vegetation types. This mosaic consists of an alternating succession of grasslands in linear thalwegs with Q. infectoria interspersed among rocky hills dominated by Q. coccifera. Below 1,500 meters a.s.l., various habitat types bear traces of ancient agriculture. Old terraces, constructed with rocks, are prevalent remnants of agriculture. Often reclaimed by shrubs or trees, these terraces comprise a mix of rocky micro-habitats and grasslands. Another common trace of past agriculture is the presence of rock heaps, remnants of stones cleared for ploughing, mainly located in thalwegs.

The woodlands on Mount Hermon were previously characterised as similar to those on Mount Lebanon, distinguishing them from those of Anti-Lebanon (Abi-Saleh 1982; Abi-Saleh and Safi 1988). However, some typical Mediterranean taxa were absent in Mount Hermon. For instance, in the supra-Mediterranean belt, Acer obtusifolium, Arbutus andrachne, Cercis siliquastrum, Laurus nobilis, Phillyrea latifolia, and Pinus brutia were absent, and similarly, in the montane-Mediterranean woodlands, Acer hyrcanum subsp. tauricola, Fraxinus ornus, and Ostrya carpinifolia were also missing. Intriguingly, additional elements have offered insights into floristic affinities between the eastern slopes of Mount Barouk’s and the western slopes Mount Hermon. These indications include the absence of certain Mediterranean tree species that are typical of western Mount Lebanon, and the shared presence of the same narrow endemic taxa, namely Allium feinbergii, Bellevalia hermonis, Quercus look, and Salvia rubifolia (Mouterde 1966, 1970, 1984).

This study provides the first comprehensive list of plant taxa of the western slopes of Mount Hermon in Lebanon utilizing a habitat-based approach. The significance of elevation, mean annual temperature, slope and northness in shaping the distribution of taxa and habitat types has been demonstrated. The impact of anthropic activities is also an intriguing aspect that should be more frequently quantified and included in studies. However, understanding historical impacts without proper documentation and verified references can be challenging, and the landscapes stand as the last remaining means to decipher the history of the region.

Floristic affinities with Mount Barouk, located in the south part of Mount Lebanon, were highlighted. The analysis of floristic composition allowed the identification and characterisation of ten habitat types: three at the oro-Mediterranean level, hedgehog-heaths of Astragalus echinus and Noaea mucronata in thalweg and slopes, hedgehog-heaths of Tanacetum densum and Astragalus cruentiflorus, cliffs of Rosularia sempervivum subsp. libanotica, three at the supra-Mediterranean level, namely grasslands with Eryngium glomeratum, woodlands of Quercus infectoria, Q. coccifera and Crataegus azarolus, woodlands of evergreen Q. coccifera, and four at the montane level, namely scree deciduous woodlands of Prunus korshinskyi and Lonicera nummulariifolia, woodlands of deciduous P. korshinskyi and evergreen Q. coccifera, shrublands of Astragalus gummifer, deciduous woodlands of Quercus look and Acer monspessulanum subsp. microphyllum. Five novelties can be added to the national typology of habitat as sub-types.

Our research yielded 383 taxa including twenty-four endemics to Mount Hermon and Mount Lebanon, two taxa endemic to Mount Hermon and Anti-Lebanon, and one exclusively endemic to Mount Hermon. It provides a complementary list of taxa for the region. The oro-Mediterranean hedgehog-heath of Astragalus echinus and Noaea mucronata hosted the highest number of endemic plant taxa (12), followed by the montane woodlands of Quercus look and Acer monspessulanum subsp. microphyllum (10), the scree deciduous montane woodlands of Prunus korshinskyi and Lonicera nummulariifolia (6), and by montane thalweg deciduous thickets of Astragalus gummifer (5). The vulnerability of specific habitat types, particularly Q. look woodlands and Juniperus excelsa woodlands, as a result of past exploitations, should be considered. This highlights the need for protective measures aimed at conserving these woodlands and enhancing their restoration. Such initiatives could offer dual benefits by preserving the environment and also supporting pastoralist activities that require shaded areas during hot summer days.

Finally, the habitat mapping serves as a valuable tool for visualizing the distribution of habitats and surrounding human activities. It constitutes a crucial resource for the effective management and conservation of the natural heritage. The comprehensive map reveals that the nature reserve on the western slopes of Mount Hermon encompasses the majority of the identified habitats. The insights gained from this study are instrumental in informing the development of a management plan for the nature reserve, ensuring the preservation of its diversity.

The data related to the geographic coordinates and elevation, list of observed plant species, and percentage frequency and diagnostic value for each species within each plant community are provided as Suppl. materials 1–4. The entire data are available upon request to the corresponding author.

HE, LC, SB and CK conceptualized the study, carried out the investigation and designed the visualisation of the results. HE conducted the fieldwork and data collection, curated the data, designed the methodology, carried out the analyses, wrote the original draft and took the photographies. LC, SB, CK, DC and MM supervised the study, reviewed and edited the manuscript, were responsible for acquiring funding and were part of the project administration.

The authors are grateful to the Observatoire Libano-Francais de l’Environnement (O-LIFE, presently NeoLife) for supporting this work (contribution number SA 15-2022). The authors would also like to acknowledge the “STEPping up Nature Reserves Capacity – STEP4Nature” project funded by the Ministry of Foreign Affairs and International Cooperation of the Italian Republic through the Italian Agency for Development Cooperation (AICS) and implemented by the United Nations Development Programme (UNDP) in coordination with the Ministry of Environment of Lebanon for contributing to field surveys. The authors are thankful to Mehdi Fayeq for accompanying the project team in the field and sharing invaluable information about the area. The authors would like to express their gratitude to Zdeňka Lososová, Idoia Biurrun and the two anonymous reviewers for their valuable remarks, which have contributed to enhancing the quality of this paper.

• Hicham El Zein (Corresponding author, hichamelzzein@gmail.com), ORCID: https://orcid.org/0000-0001-7541-9509
• Lamis Chalak (lamis.chalak@ul.edu.lb), ORCID: https://orcid.org/0000-0003-1301-982X
• Safaa Baydoun (safaa.baydoun@bau.edu.lb), ORCID: https://orcid.org/0000-0003-1820-4995
• Carla Khater (ckhater@gmail.com)
• Dominique Choueiter (dominique.choueiter@undp.org)
• Maher McKenna (maher.mckenna@undp.org)