Rhodope Mountains Research Articles

First Report of Troglotrema acutum Trematoda Parasitizing a European Polecat (Mustela putorius) in Bulgaria

The finding also represents the first detection of this trematode on the Balkan Peninsula. The study was conducted between 2014 and 2023. Nineteen road-killed polecats, mainly from southern Bulgaria, were examined. A four-year-old male polecat road-killed near Chepelare, a town in the Somlyan Province in the Rhodope Mountains, was infested with six adult Troglotrema acutum within its frontal sinus. The skull exhibited only weakly developed lesions. The prevalence of 5.26% observed in this sample was lower than values reported from other European countries. This finding extends the known southeastern distribution range of T. acutum by over 700 km.

Grassroots Activism and Resistance in the Rhodope Mountains (Bulgaria)

Grassroots Activism and Resistance in the Rhodope Mountains (Bulgaria)

Iron Age ceramics from Thracian rock-cut complexes from Bulgaria – Mineral magnetic relics of technological production and use

The Gluhite kamani Thracian rock-cut complex in the Eastern Rhodopes Mountain is famous with its more than 500 rock niches carved in the rock at heights up to 20 m. Continuous habitation starting from the final Chalcolithic (the second quarter of the 4th millenium BCE) until the Late Classical – Early Hellenistic period (late 5th – 4th century BCE) provides unique opportunity for studying diachronic changes in pottery production and use. In this contribution, systematic analysis of a collection of 135 ceramic sherds from five archaeological periods at the site was carried out using a combined mineral magnetic and geochemical approach. Magnetic susceptibility (χ), frequency-dependent magnetic susceptibility (χfd%) and firing temperature (Tfire), determined using the magnetic susceptibility method, were combined with data from elemental XRF analyses. Thermomagnetic measurements, employed for identification of magnetic minerals revealed the dominant presence of (titano)magnetite with low Ti-content and/or a fraction of single-domain magnetite and in few cases hematite. Although varying in a wide range, median χ values of ceramic sherds from the Early Iron Age (EIA) periods show similar distribution, while for Late Iron Age (LIA) with the introduction of the wheel-thrown pottery, χ values are higher, presumably due to decreased amount of silica-rich clastics in the clay. Concurrently, χfd% values decrease in ceramics from the LIA, indicating predominant presence of stable single-domain magnetite in the iron oxide composition of the ceramics. Firing temperatures (Tfire) estimations display a systematic pattern of two groups – higher (Tfire between 760 and 800 °C) and lower (Tfire ∼ 400–––600 °C). During the EIA periods both Tfire groups are present, characterized by systematic gradual decrease of the median value of the low Tfire when going from EIA1 towards the EIA2. Wheel-thrown pottery from the LIA show low Tfire ∼ 400 °C only. Based on the differences in thermomagnetic properties of ceramics, their magnetic parameters and Tfire estimates, two possible hypotheses are suggested to explain the observed changes in EIA ceramic characteristics: i) utilization of two differently sourced clay materials (illite-dominated and montmorillonite-dominated) for production of ceramics fired at higher and lower temperatures, respectively; and ii) utilization of one raw clay source, while using two firing regimes – firing at higher temperature for prolonged time, and fast firing to high temperature with successive stage of longer firing at lower temperature. Differences in thermomagnetic properties of wheel-thrown pottery from the LIA period leads to the assumption for utilization of diverse clay source for their production, as compared clay sources for the Early Iron Age periods.

A Comparison between Bulgarian Tanacetum parthenium Essential Oil from Two Different Locations.

Tanacetum parthenium L. (Asteraceae) is a perennial herbaceous plant with a long-standing historical use in traditional medicine. Recently Tanacetum parthenium L. essential oil has been associated with a promising potential for future applications in the pharmaceutical industry, in the cosmetics industry, and in agriculture. Investigations on the essential oil (EO) have indicated antimicrobial, antioxidant, and repellent activity. The present study aimed to evaluate the chemical composition of Bulgarian T. parthenium essential oil from two different regions, to compare the results to those reported previously in the literature, and to point out some of its future applications. The essential oils of the air-dried flowering aerial parts were obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was evaluated using gas chromatography with mass spectrometry (GC-MS). It was established that the oxygenated monoterpenes were the predominant terpene class, followed by the monoterpene hydrocarbons. Significant qualitative and quantitative differences between both samples were revealed. Camphor (50.90%), camphene (16.12%), and bornyl acetate (6.05%) were the major constituents in the feverfew EO from the western Rhodope Mountains, while in the EO from the central Balkan mountains camphor (45.54%), trans-chrysanthenyl acetate (13.87%), and camphene (13.03%) were the most abundant components.

Annual and Seasonal Characteristics of Rainfall Erosivity in the Eastern Rhodopes (Bulgaria)

Rainfall, with its intensity, duration, and seasonal distribution, is among the main factors causing soil erosion, which is a widespread environmental problem in Bulgaria. Rainfall erosivity shows the potential of precipitation to generate erosion processes and is an essential indicator of the climate vulnerability of a region. This paper aims to evaluate rainfall erosivity in a part of the Eastern Rhodopes Mountains, an area that is characterised by high-intensity erosion processes and high erosion risk. Local peculiarities of rainfall erosivity were revealed by the calculation of some precipitation indices based on the monthly precipitation for the period 2000–2021, such as the precipitation concentration index (PCI), Angot precipitation index, Fournier index (FI), and modified Fournier index (MFI). The analysis of the extremely wet and extremely dry months at the annual and seasonal (October–March and April–September) levels was performed to evaluate the susceptibility to erosion. The results from the study show that rainfall erosivity in the studied area varies from low to moderate in the northern part of the study area and from high to very high in the south. According to the MFI, high and very high erosivities have been observed mainly since 2012. The erosivity increases from north to south, to the area with a complex relief, where the combination of orography and atmospheric circulation make favourable conditions for the occurrence of extreme precipitation. The analyses of the calculated indices show that the precipitations in most of the studied area generally have from a low to a moderate erosivity, but this does not exclude the occurrence of cases with high and very high erosivities, which are characteristic of recent years and are related to the increase in annual precipitations and extreme precipitation months. The results of this study can contribute to the development and implementation of measures and preventive activities for the reduction and possible elimination of the negative impacts of extreme precipitation.

Bioactive compounds of Arctostaphylos uva-ursi wild-growing populations from Bulgaria

Arctostaphylos uva-ursi (L.) Sprengel (bearberry), Ericaceae is a valuable medicinal plant with diuretic and uroantiseptic action which is mainly due to arbutin. In Bulgaria the species is considered as rare. Content assessment of bioactive compounds of A. uva-ursi leaves from three natural populations from Bulgaria was the aim of the present study. Leaf samples were collected from Pirin, Vitosha, and Rhodope Mountains. Bioactive compounds in the methanolic extracts of the samples were analysed by GC/MS. Total phenolic content was determined using Folin–Ciocalteu reagent. Arbutin, quinic acid and gallic acid were detected in the highest amounts. Catechine, 4-hydroxybenzoic acid, chlorogenic acid, triterpenes (α- and β-amyrin, uvaol and lupeol) and other primary and secondary metabolites were found, also. Differences in the content of individual compounds between samples of different origin were established. The highest total phenolic (182.98 mg GAE g-1) and arbutin (8.4%) content was found in the sample from Vitosha Mountain. The presented data characterizes the profile of bioactive compounds in the Bulgarian bearberry raw material for the first time.

Morphometric analysis of the drainage network in the Parvenetska river basin, the Western Rhodopes Mountains

The aim of this study is to analyze selected morphometric properties of drainage network in the Parvenetska river basin, the northwestern Rhodope Mountains. In this regard, the watershed of the main river was divided into seven sub-basins. For each of them, the following linear and areal morphometric parameters were considered: area and shape of the catchment, slopes, drainage network length, drainage density, stream frequency, bifurcation ratio, Meltonʼs index, hypsometric integral, etc. The morphometric analysis can be used for creating of hydrological and geomorphological models for natural hazards and for better planning of sustainable use of water resources in the area.

GIS-based landslide and rockfall susceptibility zoning in Chepelarska River Basin (Western Rhodope Mountains, Bulgaria)

Landslides and rockfalls are one of the most widespread hazardous phenomena in the Western Rhodopes, Bulgaria. These mass-wasting types occur together with other dangerous phenomena such as river bank erosion and soil degradation, and can cause a lot of infrastructural damage. The main purpose of this paper is to perform GIS-based landslide and rockfall susceptibility zoning and to elaborate susceptibility maps at a scale of а river basin on the example of the Chepelarska River Basin (RB). In order to achieve this goal, nine causal factors have been selected, and map of landslides and field study have been used. These factors were reclassified using histograms and the natural breaks method. In addition, the frequency ratio values of each class have been calculated. To obtain the causal factors impact on sliding and rockfalls, the weights and weighted averages sum of their classes were calculated and analysed. For the complex analysis and elaboration of mass-wasting susceptibility maps, weighted overlay and weighted sum methods have been applied. The obtained results show that from the total 38 landslides and rockfalls in the study area, 26 of them fall into the very high susceptibility zone applying a weighted overlay, and 25 of them fall into the same zone using the weighted sum method. These results and the used methods could be used for other small and medium-sized river basins.

Physicochemical, Antioxidant, and Antimicrobial Properties of Three Medicinal Plants from the Western Part of the Rhodope Mountains, Bulgaria.

The present study examined the physicochemical, antioxidant, and antimicrobial properties of three medicinal plants: thyme (Thymus callieri Borbás ex Velen), cotton thistle (Onopordum acanthium L.), and hawthorn fruit (Crataegus monogyna Jacq.) from the Western Rhodope Mountains, Bulgaria. The first stage determined the physicochemical characteristics (moisture, ash, carbohydrates, proteins, and vitamin C) of the three herbs. The second stage investigated four types of extracts (aqueous, oil, methanolic, and ethanolic) of each herb and evaluated their total phenolic content, the presence of phenolic compounds (flavonoids and phenolic acids), their antioxidant activity, and antimicrobial properties. Thyme was characterised by the highest ash, protein, and vitamin C content (6.62%, 11.30%, and 571 mg/100 g, respectively). Hawthorn fruit showed the highest moisture and carbohydrate content (8.50% and 4.20%, respectively). The 70% ethanolic extracts of the three herbs exhibited the highest levels of phenolic compounds and, consequently, pronounced antioxidant activity, compared to the other three types of extracts. The aqueous, oil, methanolic, and ethanolic thyme extracts demonstrated the highest total phenolic content-TPC (27.20 mg GAE/g, 8.20 mg GAE/g, 31.70 mg GAE/g, and 310.00 mg GAE/g, respectively), compared to the extracts of the other two plants. These results were consistent with the highest antioxidant activity of the thyme extracts determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, the oxygen radical absorbance capacity (ORAC) assay, and the hydroxyl radical averting capacity (HORAC) assay (except for the oil extract examined using the DPPH method). The results from the high-performance liquid chromatography (HPLC) analysis revealed that the flavonoid quercetin-3-ß-glucoside had the highest concentration in thyme (374.5 mg/100 g), while myricetin dominated in the cotton thistle (152.3 mg/100 g). The phenolic acid content analysis showed prevalence of rosmaric acid in the thyme (995 mg/100 g), whereas chlorogenic acid was detected in the highest concentration in the cotton thistle and hawthorn fruit (324 mg/100 g and 27.7 mg/100 g, respectively). The aqueous, methanolic, and ethanolic extracts showed moderate to high antibacterial potential but limited antifungal activity. None of the oil extracts inhibited the test microorganisms used in the study.

“Privileged” and “deprived” in the Rhodopes: how Local Inhabitants become Activists Fighting to Keep Small Mountain Communities Alive

The presented research focuses on the ways people from small village communities in the Rhodope Mountains (Bulgaria) have united to take measures against the realization of private business interests and investments – the opening of quarries for the extraction of marble and ballast that would disrupt the established regimes of environmental protection in the region of the Middle Rhodopes - these are the protected areas included in the UNESCO biosphere reserve Chervenata sténa (Red wall) and the ecological network “Natura 2000”. The text is focused on people’s strategies of coping with change and uncertainty such as protests and social resistance movements that mobilize public support through social, kinship and political networks. The following issues are discussed in more detail: the emergence of new political, cultural, and ecological awareness of mountain communities fighting against the environmental exploitation of their territories; the role of the new inhabitants and their families in preserving local livelihoods and traditions, and the many forms of negotiation on how living together, including different visions and even conflicts on practices of resource management, sustainability, and heritage.

Forgotten Stories of Yogurt: Cultivating Multispecies Wisdom

Thanks to recent human microbiome research, we are gradually gaining a better understanding of the vital role that microbial diversity plays in health and well-being. However, as industrial food production standardizes fermented foods—making monoculture “probiotics”—we risk losing both microbial diversity and the cultural heritage of how to sustain it. This article takes yogurt as a case study to explore the ongoing disappearance of microbial biodiversity and its relationship to food practices. As an ancient fermentation product, yogurt has a rich biocultural heritage that is reflected in its diverse preparation methods—including, as this article describes, using ants and spring rain. I employed autoethnography as a form of qualitative inquiry to trace the stories of yogurt passed down through generations in my community from the Rhodope Mountains. Here multispecies and sensory approaches allowed me to delve into the intimate cultural and personal aspects of yogurt making. The stories I gathered from Bulgaria and Turkey reveal the richness of interspecies and sensorial connections involved in yogurt production. I argue that these practices cultivate diverse multispecies relationships and provide valuable insights into the broader loss of biocultural diversity. This article is thus an invitation to reflect on the ways in which the contemporary biodiversity crisis is related to the loss of local cultural knowledge, skills, and wisdom that have long nurtured diverse and generative multispecies relationships.

A Study of the Chemical Composition, Antioxidant Potential, and Acute Toxicity of Bulgarian Tanacetum vulgare L. Essential Oil.

Common tansy (Tanacetum vulgare L.) is a plant with medicinal properties that has traditionally been used in folk medicine for its anthelmintic, antispasmodic, and choleretic effects, for the treatment of diarrhea and digestive problems, and externally, as an insecticide in veterinary practices. In the current study, we investigated, for the first time, the chemical profile and antioxidant activity of essential oil from a wild population of T. vulgare L. growing in Bulgaria. Common tansy essential oil (EO), which is rich in bicyclic monoterpenes, was obtained using hydrodistillation and characterized by using gas chromatography-mass spectrometry (GC-MS). Thirty-seven compounds were identified in Bulgarian tansy EO. Among the major constituents were oxygenated monoterpenes, including compounds such as camphor (25.24%), trans-chrysantenyl acetate (18.35%), cis-verbenol (10.58%), thujone (6.06%), eucaliptol (5.99%), and α-campholenal (5.98%). The analysis results identified the essential oil from T. vulgare L. grown in the western Rhodope Mountains of Bulgaria as the camphor chemotype. Furthermore, its antioxidant activity was analyzed using the oxygen radical absorbance capacity (ORAC) method and was found to be 605.4 ± 49.3 µmol TE/mL. The essential oil was also tested for single-dose acute toxicity on Wistar rats and was found to be non-toxic by oral administration. The mean lethal dose by intraperitoneal administration was LD50 i.p. = 14.9 g/kg body weight. The results of the conducted study can serve as a basis for the evaluation and subsequent exploration of other pharmacotherapeutic effects of the essential oil obtained from the inflorescences of the Bulgarian species T. vulgare L.

Composition and diversity of bacterial communities associated with honey bee foragers from two contrasting environments.

The honey bee is associated with a diverse community of microbes (viruses, bacteria, fungi, and protists), commonly known as the microbiome. Here, we present data on honey bee microbiota from two localities having different surrounding landscapes - mountain (the Rhodope Mountains) and lowland (the Danube plain). The bacterial communities of abdomen of adult bees were studied using amplicon sequencing of the 16S rRNA gene. The composition and dominance structure and their variability within and between localities, alpha and beta diversity, and core and differential taxa were compared at different hierarchical levels (operational taxonomic units to phylum). Seven genera (Lactobacillus, Gilliamella, Bifidobacterium, Commensalibacter, Bartonella, Snodgrassella, and Frischella), known to include core gut-associated phylotypes or species clusters, dominated (92-100%) the bacterial assemblages. Significant variations were found in taxa distribution across both geographical regions and within each apiary. Lactobacillus (Firmicutes) prevailed significantly in the mountain locality followed by Gilliamella and Bartonella (Proteobacteria). Bacteria of four genera, core (Bartonella and Lactobacillus) and non-core (Pseudomonas and Morganella), dominated the bee-associated assemblages of the Danube plain locality. Several ubiquitous bacterial genera (e.g., Klebsiella, Serratia, and Providencia), some species known also as potential and opportunistic bee pathogens, had been found in the lowland locality. Beta diversity analyses confirmed the observed differences in the bacterial communities from both localities. The occurrence of non-core taxa contributes substantially to higher microbial richness and diversity in bees from the Danube plain locality. We assume that the observed differences in the microbiota of honey bees from both apiaries are due to a combination of factors specific for each region. The surrounding landscape features of both localities and related vegetation, anthropogenic impact and land use intensity, the beekeeping management practices, and bee health status might all contribute to observed differences in bee microbiota traits.

Geomorphological and Sedimentological Indicators of Contemporary Erosion Processes: An Example of the Eastern Rhodopes Mountains (Bulgaria)

Erosion processes, triggered by water, occur and propagate on sloping surfaces and have a significant negative impact on the soil quality and vegetation, as well as cause a change of the topographic surface. In the long term, they can lead to an increase in sediment transport, siltation of dams, and higher flood hazard. The development of water erosion reflects on the slope profile and the specific landforms like rills and gullies. In this regard, the geomorphological features of the areas can be considered indicators of the spatial distribution of erosion and accumulation. The sediment properties give information about the conditions of the transport and the intensity of the hydrogeomorphic processes. The current study aims to analyse the short-term changes in erosion and deposition by application of morphometry and grain size analysis. Topographic wetness index (TWI) and cross-section profiles of two small gullies were analysed based on high-resolution digital terrain models (DTMs), generated from unmanned aerial system (UAS) data. Remote sensing was combined with field geomorphological research and sediment sampling. The results of the research show about average 2 cm change in erosion and deposition for the period October 2021 – November 2022. Despite TWI and cross-section profiles depending on the DTMs resolution, they are reliable indicators for erosion and deposition. The grain size analysis supports the morphometric analysis. Coarse to very fine sands are predominant in most cases of sediment sampling. The sorting coefficient shows very poorly to moderately sorted deposits which indicates transport in a more dynamic environment and temporary flow.

Salix ×browiczii (Salicaceae) – a new nothospecies from northeastern Greece

A hybrid between Salix triandra and S. xanthicola, occurring in the Rhodope Mountains in northeastern Greece, is described as a new nothospecies. It differs from S. triandra by having distinctly hairy young stems and more deeply serrate-dentate leaf margins, and from S. xanthicola by a smooth, unstructured (without conicoids) wax layer on the lower side of the leaves and the presence of subsessile glands on the petioles.

Faunal remains from the Early Iron Age rock-cut complex Gluhite Kamani (Eastern Rhodopes, Bulgaria)

The faunal remains recovered from the Gluhite Kamani site offer the unique opportunity to explore the consumption patterns of the Early Iron Age communities inhabiting the Rhodope Mountains. While a lot high-altitude and rock-cut sanctuaries have been registered within the Rhodope Mountains, this is the only site yielding a larger assemblage (n = 3160) from a stratigraphic sequence dating to the Late Bronze Age - Early Iron Age transition and the Early Iron Age. Domestic animals dominate, with sheep/goat being the main exploited species through all stratigraphic layers. The results show that the percentage of represented domestic animals is relatively continuous, while the number of wild animals seems to vary throughout the different periods., As the site is regarded as a sanctuary during the Iron age, the extent to which we can identify any ritual activity from the osteological assemblage is commented on in the discussion regarding the cull patterns observed, and taphonomy.

Ethnobotanical and Ethnopharmacological Study in the Bulgarian Mountain Rhodopes: Part II—Contemporary Use of Medicinal Plants

Rhodopes Mountain is ethnobotanically poorly studied, but our preliminary observation in a number of settlements revealed that even nowadays, the local population relies solely on previously collected medicinal plants. We aimed to assess the contemporary use of medicinal plants in the Central and East Rhodopes and the health conditions that local communities address with them. The ethnobotanical field data were collected through an in-depth method in combination with semi-structured face-to-face interviews, adapted with modifications to the objectives of this study. The following quantitative ethnobotanical indices were used in this study: informant consensus factor (ICF), fidelity level (FL), and Jaccard similarity coefficient or Jaccard index (JI). Data analyses from our field research showed that 92 informants mentioned the utilization of a total of 114 plant species. The results of this study reveal that in both regions of the Rhodopes, medicinal plants are mentioned most often in relation to diseases affecting nervous, respiratory, digestive, and cardiovascular systems, followed by reproductive, urinary, immune, and musculoskeletal. The risk of disruption or loss of traditional knowledge of medicinal plants is expected in the condition of cultural globalization. However, there is no metrified data about the use of medicinal plants in the Rhodopes from the past. The application of statistical indices in this research will make such assessment and monitoring possible in the future.

Editorial Note: Rhodopes Mountains - a fairy tale in green – Part I (Eastern Rhodopes)

Editorial Note: Rhodopes Mountains - a fairy tale in green – Part I (Eastern Rhodopes)

Characterization of Serpentine Soils from Eastern and Southern Rhodope Mountains (Bulgaria)

This work aims to characterize serpentine soils in Bulgaria and examine the biogeochemistry of pedogenic Ni and its relation to Ni available forms. Soils were collected from serpentine soils of the Eastern and Southern Rhodopes (Bulgaria). The chemical composition of serpentine soils is similar to serpentine soils from the Balkan Peninsula and is characterized by high contents of Ni (919.9–2397.2 mg.kg–1). The soils had a neutral to slightly alkaline reaction (pH 6.4 to 7.6) and a medium to high organic matter content. Of the primary minerals, those of the serpentine group (antigorite and lizardite), the talc group (willemseite), the amphibole group (riebeckite), the feldspar group (albite) and quartz are mainly present in the soil samples. The secondary minerals present in the samples include calcite and dolomite, and also representatives of the clay minerals, clinochlore and montmorillonite. The contents of free iron oxides (Fed), amorphous iron oxides (Feo), well-crystallized iron oxides (Fecr) (Fed-Feo) and activity index (Feo/Fed) showed significant differences (p<0.05) among soils from different locations. In the soils from Dobromirtsi, Parvenets, and Golyamo Kamenyane Ni bound to Fe oxides were evenly distributed between the well-crystallized and amorphous phases. In the soils from Kardzhali, Chernichevo and Dyulitsa more than half of the Ni bound to Fe oxides were bound to or occluded in amorphous Fe oxides, while in the soils from Kazak were bound to well-crystallized Fe oxides. Pedogenesis, weathering intensity, and Fe geochemistry influence Ni availability in serpentine soils.

RESISTANCE IN COMMON BEAN(PHASEOLUS VULGARIS L.) TO UROMYCES APPENDICULATUS IN BULGARIA

Common bean rust, caused by Uromycesappendiculatus, is one of the most devastating diseases in common bean. Breeding for resistant cultivars is the most effective and eco-friendly method for disease control. Although there is no targeted breeding program in Bulgaria to create resistant cultivars to the pathogen, periodic screening of the virulent diversity of U. appendiculatus and sources of resistance to the identified races/pathotypes is carried out. During the last twenty years, four investigations were made to estimate virulence diversity in pathogen population. Eleven U. appendiculatus races (20-0, 20-1, 20-2, 20-3, 20-19, 29-0, 29-1, 28-1, 52-3, 20-16 and 20-18) are identified, distributed in Rhodope mountains and North Bulgaria. Chronologically each of the studies was accompanied or followed by a screening for sources of resistance to the pathogen under field conditions. Еach study found different numbers of resistant accessions depending on the virulent potential of the population used. In three of the studies, cultivars that showed resistant phenotype under field conditions were screened against a set of races, distributed in the country in the same time, under greenhouse. Bulgarian cultivar ‘Beslet’ showed resistant reaction under field and greenhouse in all investigation. The resistance of the cultivar to races 20-1 and 20-19 is governed by a single dominant gene. This cultivar can be successfully used in a breeding program for race-specific resistance. Fifty accessions with race-nonspecific resistance, expressed by low disease intensity and resistant/susceptible infection type, are identified in two investigations under field conditions.