Northeastern Bulgaria Research Articles

New habitats of some species of orchids on the territory of the European ecological network Natura 2000 (Bulgaria)

We present new data on the distribution of five orchid species in the Batova Valley Protected Area BG 0000102, part of the European ecological network Natura 2000. Although these orchid species are not new to the floristic region of Northeastern Bulgaria, we report new habitats in Batova River Valley Protected Area. Three of the species are reported for the first time, for the other two species, this is the second report in the study area. All described orchid species are subject to protection by various national and international documents.

Survival and growth of Common beech (Fagus sylvatica L.) provenances in North-Eastern Bulgaria

Two provenance tests in  North-Eastern Bulgaria have been studied, whose purpose is to test the response of beech provenances from Southern Germany to the drier and warmer climatic conditions in Bulgaria, in order to predict how they would perform in a warming and drying climate. The provenance tests were established in the spring of 2010 in the area of the Varbitza and Kipilovo Forest Services with 2-year-old seedlings in a 2 x 1 m scheme in 3 replications. Four provenances of common beech were studied - 2 German (Silberbach and Ebersdorf) and 2 Bulgarian (Petrohan and Berkovitza). On the 12th year after afforestation, an inventory and measurements of the height and root collar diameter were carried out. The results were processed statistically by applying one and two-factor analysis of variance, as well as Tukey’s test for multiple comparisons. A higher survival rate was found in the provenance test in Kipilovo. The Bulgarian provenances Petrohan and Berkovitza were characterized by better growth in height in both provenance tests, and in root collar diameter - provenance Petrohan. Provenance Ebersdorf could be recommended for use in drier and warmer places in Southern Germany.

Bioevents at the Konkian/Sarmatian boundary (Northeastern Bulgaria) – a response to paleoclimatic changes

New outcrops of the Konkian part of the Euxinograd Formation, located between Briz beach and Trakata beach, have been studied. The section comprises an alternation of gray calcareous clays, laminated calcareous clays and limestones, whose age is determined by mollusks and diatoms and ranges from the Konkian to the Sarmatian. The studied sediments were deposited in a shallow-marine environment with frequent fluctuations of the sea level. The fossil diatom flora is characterized by a monotonous species composition. The presence of crushed diatom valves and a relatively abundant sand fraction suggest intermittent high water dynamics. Generally, the climate was warm, with at least three dry periods, during which the alkalinity and CaCO3 content increased significantly and the living conditions of the mollusks and diatoms deteriorated.

Quantitative Holocene palaeolandscape reconstructions in the Beloslav Lake area using pollen data, modelling and simulation approach

Pollen records from lacustrine core Bel-1 obtained from the Beloslav Lake (Northeastern Bulgaria) were used to reconstruct the past vegetation and to simulate past landscapes. Numerous 50 km by 30 km landscape simulations were performed at different time windows in the past. Eleven of them were chosen as significant for vegetation dynamics, human impact, and landscape evolution. Comparison of actual and simulated modern vegetation composition showed similar results, which proved the reliability of models. Quantitative reconstructions in the region of the Beloslav Lake showed a clear trend of decreasing forest landscapes at the expense of agrarian ones. Simulated landscapes based on quantitative reconstruction of vegetation coverage reflected a more significant anthropogenic impact and openness than those shown by pollen percentages.

Organic oat production (Avena sativa L.) in the conditions of Northeastern Bulgaria

Abstract. The study took place in the period 2018 - 2020 in the village of Milanovo, Shumen region. In the period March 23 - 30, in accordance with the climatic factors of each year, the spring oat variety Scorpion was sown at a sowing rate of 3000 - 4000 germinating seeds per ha. Oats were sown after a predecessor crop of nettle. The aim of the present study is to prove that the oat variety Scorpio is suitable for organic production and it gives a quality product for direct consumption. The cultivation method and the finished product processing are also described in the study. The soil is gray-brown forest soil (Luvisols, Lessive - FAO UNESCO). Oats were grown following the requirements for field crop organic cultivation. In the period of vegetation, the crop was watered twice at a rate of 0.4 - 0.6 mᶾ /ha. The crop was harvested for green mass, at the maturity stage, as mowing was done in late June in two stages with a herb mower. The harvested area was 1.23 ha, and the green mass yield obtained was 10 t, on average for the period. The green mass followed a drying process in the sun, as a result of which 2470 kg of dry oat stalks were obtained. After that, we could prepare bundles measuring the length of 20 - 25 cm, packed in nylon and also aligned at the rear end. Each bundle weight varied from 100 to 300 g. After the dedusting process of bundles we were able to obtain a product for direct consumption showing fiber length of 0.4 - 3 mm. The sown area was identified as having the following groups of weeds: winter-spring (Chamomilla recutita Rauchert, Consolida regalis SPGray, Centaurea cyanus L. and Papaver rhoeas L.), early spring (Sinapis arvensis L., Bifora radians MB, Polygonum convolvulus L., Galium tricorne With, Avena fatua L.), ephemeral (Veronica hederifolia L., Stellaria media (L.), Holosteum umbelatum toothed swan) and root-shoot (Cirsium arvense Scop., Convolvulus arvense L. Cardaria draba L.). We could not detect any fungal disease attacks by: Puccinia coronata, Ustilago avenae, Ustilago hordei, Fusarium sp. Powdery mildew (Erysiphe graminis De Candole f. Sp. Avenae) and striped leaf spots (Pyrenospora avenae) had a weak effect on the crop (up to 25%). The study period showed the average content in the crop as follows: protein - 10.56%, starch - 43.62%, ash - 4.24%, and fiber - 13.47%.

Sociokulturel betydning af tragtbægerkulturens tidligneolitiske flintøkser

Sociokulturel betydning af tragtbægerkulturens tidligneolitiske flintøkser

Comparative analysis of the myriapod fauna (Diplopoda, Chilopoda) of the Shumen Plateau and the Madara Plateau (Northeastern Bulgaria)

Abstract At present, the inventory lists of the Myriapoda of many geographical areas in Bulgaria and the comparative analyzes of the similarity between such local faunas are scarce or completely missing. The present paper presents the results of the comparative analysis of α- and β-diversity of the myriapoda communities in natural habitats in two regions in Northeastern Bulgaria – the Shumen Plateau and the Madara Plateau. The compared habitats in these plateaus have similar geographical, soil and climatic conditions, and similar species composition of plant formations. The analysis of the structure of the myriapoda communities included estimation of species diversity by determining the Shannon-Wiever index (H’) and the Berger-Parker index (d). The degree of similarity between the species composition of the communities was analyzed by the Czekanowski-Dice-Sörensen, Jaccard, Bray-Curtis, Horn, Morisita-Horn indices and the corrected Chao-Sörensen and Chao-Jaccard indices. The species diversity of the millipede community in the Shumen Plateau is much greater than that of the Madara Plateau, while the diversity of the centipede communities in the two plateaus does not differ significantly. In both classes the greatest species diversity is registered in deciduous and mixed deciduous-coniferous forests. Chao-Sörensen and Chao-Jaccard indices of similarity for the myriapod communities in these habitats are the highest, approaching 1, in contrast to the other sites where the registered species composition of the centipedes is smaller and the degree of similarity is about 0.6.

Survey on current status of folk medicine in Bulgaria reported by local knowledgeable persons

Abstract Traditional knowledge is of real danger to be lost in modern society. This research is a part of an ethnobotanical survey aimed on documentation of current status of folk medicine in Central and Northeastern Bulgaria. Semi-structured interviews with local knowledgeable persons were provided. Quantitative ethnobotanical indices consisting of Fidelity level (FL) and Informant consensus factor (ICF) were calculated as indicatives of local importance of species and prevalent uses of species. The respondents reported 15 category uses: to treat 12 health disorders, for prophylaxis/immune stimulation, other health connected conditions and plants included in the diet as food/spices. The highest number of plants was used for the treatment of gastrointestinal diseases (65.9%), cardiovascular problems (53.4%) and urinary system problems (46.6%). It should be noted that many herbal medicines are related to disease prevention (52.3%). Maximum FL value (100%) of Hypericum perforatum for digestive and nervous system disorders and Thymus sp. for respiratory system diseases was calculated. Numerous species and specific applications were listed in the paper, contributing to the base ethnobotanical data. Specific use categories indicate most spread health disorders and proved treatments in the studied regions. Results also reflect the growing interest in disease prevention (immune stimulation) and a healthy diet.

THE THRACIANS AND THE WRITING

The article offers a summary and analysis of the available texts written in the Thracian language, which became especially necessary after the breakthrough finding in 1988 of new written monuments in Thracian in the settlement of Zone on the Aegean coast in Greece. Contrary to popular belief that the Thracians were an illiterate people, it can be concluded that by the 4th century BC there were three centers of writing activity in the Thracian lands: Northeastern Bulgaria (the inscription from the village of Kjolmen), the Upper Thracian plain (the inscription on the ring from the village of Ezerovo and the inscriptions on artifacts from the mounds of Duvanlii), and the Aegean coast (inscriptions from the settlements of Zone and Maroneia and from the island of Samothrace). The author examines the written evidence of the Thracian language in the context of the neighboring Greek alphabets and concludes that the existence of a local alphabet used by the Thracian population before the arrival of the Greek colonists on the Aegean coast can be postulated. Another focus of the paper is related to understanding the reasons for the gradual demise of the practice of writing in the Thracian language in the context of the emergence of the Greek local alphabets and the cultural and political reality of contacts with the Greek-speaking population and education, without neglecting the sociolinguistic aspects of the problem.

Temperature regulation in the Balkan spadefoot (Pelobates balcanicus Karaman, 1928) at the beginning of nocturnal activity.

On land, the amphibians interact with the environment in a complex way-even small changes in the physiological conditions may significantly impact the behaviour and vice versa. In ectothermic tetrapods, the transition from inactive to active phase may be related to important changes in their thermal status. We studied the thermal ecology of adult Balkan spadefoots (Pelobates balcanicus Karaman, 1928) in northeastern Bulgaria. These toads spend the daytime buried between 10 and 15 cm in sandy substrates, and emerge after sunset. On the substrate, their thermal energy exchange is defined by the absence of heat flow from the sun. Secondary heat sources, like stored heat and infrared radiation from the soil play an important role for the thermal balance of the active spadefoot toads. At the beginning of their daily activity, we measured substrate temperature (at a depth of 11–12 cm), toad’s surface body temperature, and also provided thermal profiles of the animals and the substrate surface in their microhabitats. In animals which recently emerged from the substrate, the temperature was comparatively higher and was closer to that of the subsoil on the spot. After that, body temperature decreased rapidly and continued to change slowly, in correlation with air temperature. We detected a temperature gradient on the dorsal surface of the toads. On the basis of our measurements and additional data, we discuss the eventual role of air humidity and the effects of surface and skin water evaporation on the water balance and activity of the investigated toads.

New data on the presence of the Blotched snake (Elaphe sauromates Pallas, 1814) in the region of Shumen town (Bulgaria), with emphasis on the negative human attitude toward the species

Abstract In the present study, we report on new localities in Northeastern Bulgaria, where Elaphe sauromates (Pallas, 1814) was recently detected. We registered five Blotched snakes in the region of Shumen town in the period 2018 - 2022. All of the snakes were adults, three were killed by tools impacts and two of them were road kills. To date, the Blotched snake was registered extremely rare and in rather long intervals (of several decades) in the region of Shumen. Our findings indicate that the species currently inhabits the suburban and urban territories near the villages of Ivanski, Radko Dimitrievo and Konyovets. Two of the locations are new for the 10 km grid-system used for standard monitoring of the biodiversity in Bulgaria.

The Unknown Labour Camp in Slivnitsa (August – September 1989)

The labour camp in the military unit in the town of Slivnitsa as a place of state repression in the campaign for forced name change has not been the subject of special scientific research. In early 1985, hundreds of Turks from North-Eastern Bulgaria were summoned to the military checkpoints and as "mobilized" were sent to the unit, part of which was turned into a special labour camp. In Slivnitsa and other labour camps, the mobilized were subjected to heavy physical labour and psychological harassment. In the archive of the State Security documents are kept with some of the statistics on this form of violent dealing with the most active Turks – potential opponents of the forced name change and organizers of mass protests in North - Eastern Bulgaria. The repression in the labour camp in Slivnitsa from August-September 1989, happened during a period of the hardest field work for the tobacco producers. As "reserve troops" some of the most prominent Pomaks in Southern Bulgaria, including also some Turks from the Pazardzhik and Gotzedelchevski villages, were isolated. Subjected to humiliation, harassment and ideological manipulation, more than 100 people in a month were held halfhungry and forced to engage in heavy physical labour. This state violence scared the population and interrupted all possibilities for general opposition against the communist regime. This study aims to present this form of mass repression, carried out secretly and thoroughly concealed by the communist totalitarian regime in Bulgaria and plunged into oblivion. It is based on archival documents, memories, unknown to science notes and a list of the names of those brought in in 1989 in the labour camp in Slivnitsa.

Mycobacterium bovis and M. caprae in Bulgaria: insight into transmission and phylogeography gained through whole-genome sequencing

BackgroundThis study aimed to characterize recent Mycobacterium bovis/M. caprae isolates from Bulgaria by whole-genome sequencing (WGS) to gain a first insight into their molecular diversity, transmission, and position within the global phylogeography of this important zoonotic species.ResultsThe isolates were obtained from cattle in diverse locations of Bulgaria in 2015-2020 and were identified by microbiological and PCR assays. WGS data were used for phylogenetic analysis that also included M. bovis global dataset. Thirty-seven M. bovis/caprae isolates from Bulgaria were studied and 34 of them were SNP genotyped. The isolates were subdivided into 3 major phylogenetic groups. Type Mbovis-13 (Eu2 complex [western Europe and northern Africa]) included one isolate. Mbovis-37 type included 5 isolates outside of known clonal complexes. The Bulgarian M. caprae isolates formed a sub-group within the Mcaprae-27B cluster which also included 22 M. caprae isolates from Poland, Spain, Germany, and the Republic of Congo. The Bulgarian M. caprae isolates share their latest common ancestors with Spanish isolates. The Mbovis-37 group shares a distant common ancestor (pairwise distance 22-29 SNPs) with an isolate from Poland but was very distant (> 200 SNPs) from the rest of the tree. The Mbovis-13 group shares a common ancestor with two human isolates from Germany. Phylogeographically, both M. bovis clades had limited circulation in northeastern Bulgaria while the majority of the studied isolates (M. caprae) were from central and western provinces. A phylogenetic network-based analysis demonstrated that 11 Bulgarian isolates were separated by 1 to 6 SNPs within four clusters, mostly forming pairs of isolates.ConclusionThe obtained WGS analysis positioned the Bulgarian isolates within the global phylogeography of M. bovis/M. caprae. Hypothetically, the observed phylogenetic diversity may not have resulted from livestock trade routes, but instead may reflect the deeply rooted M. bovis/M. caprae phylogeography of Europe. A high level of genetic divergence between the majority of the studied isolates suggests limited active transmission of bTB in Bulgaria during the survey period. At the same time, a possibility of the endemic presence of circulating bTB strains in the form of the latent persistent disease cannot be ruled out.

Molecular screening for fragile X syndrome in children with unexplained intellectual disability and/or autistic behaviour

Fragile X syndrome (FXS, OMIM #300624) is the most common inherited form of intellectual disability and the leading monogenic cause of autism.

An example of the adverse impacts of various anthropogenic activities on aquatic bodies: Water quality assessment of the Provadiyska river (Northeastern Bulgaria)

Anthropogenic activities deteriorate the quality of water resources, which reduces their socio-economic suitability, endangers public health, and affects aquatic life. This work presents the results of physicochemical monitoring of the Provadiyska River (Northeastern Bulgaria) and aims to assess water quality status according to the guidelines pointed out in the National regulatory standard-Regulation H-4/2012 for characterization of the surface waters. The selected river has become one of the most seriously polluted streams in the territory of the country due to the effect of various human practices occurring in the drainage basin, such as agriculture, industry, and urban development. Data about the values of ten physicochemical variables (pH, EC, DO 2 , N-NH 4 , N-NO 3 , N-NO 2 , N-tot, P-PO 4 , P-tot, and BOD 5), recorded at four measuring points during the period 2015-2020 have been used. Results obtained indicate that almost all of the parameters considered do not meet the reference norm for "Good status", thus water quality could be assessed as "Moderate". Failed variables appear to be EC, N-NH 4 , N-NO 3 , N-NO 2 , N-tot, P-PO 4 , P-tot, and BOD 5 whose highest observed content remains from two up to nine times above the maximum permissible limits of Regulation H-4/2012. Water contamination arises from different sources and activities, including the excessive fertilization of croplands, the unregulated release of animal manure from livestock farms, the uncontrolled discharge of municipal and industrial effluents into the river, etc. The expansion of sewerage systems in the settlements, the construction of wastewater treatment facilities, as well as the adoption of codes for best farming practices are among the most important actions that should be taken to reduce the deleterious effects of various anthropogenic activities on water quality.

Geomorphological characteristic of the plateaus in Northeastern Bulgaria

Geomorphological characteristic of the plateaus in Northeastern Bulgaria

A Study of the Yield of Honey in Farms from North-Eastern Bulgaria

The aim is to study the prices, cost and profitability of honey from the Ruse region. A serious problem has been defined for honey, which is a major product of regional beekeeping, respectively its profitability - steadily declining prices do not cover the rising costs of production and sale. The study found that the average prices of the online segment of organic honey compared to the same offline segment in packages of 1 kg have a difference of almost 2 times, and in the smallest cuts 3 times. The gross profit (margin) of the regional honey of the B2B offline markets in the biological and conventional segment for 2020 is negative. The study found that own B2C online channels in the conventional segment achieve a net return of 48 BGN/year per beehive, and in the biological segment - 97.92 BGN/year per beehive. The latter provides 150 beehives with a net income of 1224 BGN/month, which is the yield on the sale of organic honey on the offline B2C markets with 950 beehives. Marketing strategies of beekeeping farms in the Ruse region are needed to achieve competitiveness and profitability at the sectoral and regional level.

Factors influencing the neurodevelopment of children with family history of allergy in North-Eastern Bulgaria

Introduction Allergic diseases in first degree family members—parents and siblings, increase the risk of allergy in the child, which recently has been associated with a higher incidence of neurodevelopmental disorders in children. A relationship has been established between the nervous and immune systems, but their association in the early stages of life when they are still developing has not been studied in details yet. Aim The aim of this article is to explore the sociodemographic, nutritional and health factors influencing neurodevelopment of children with family history of allergy. Materials and Methods A cohort study was conducted in Varna, Bulgaria in the period 2017–2020. A total of 120 term children from atopic families were recruited (n=120). They were with a normal birth weight over 2500 g and followed until 13 to 31 months (24.0 ± 3.9 months). A direct individual questionnaire was applied for the sociodemographic characteristics in the family. Neurodevelopment was assessed by Dеvelopmental Profile-3 methodology, past medical history survey was applied, and anthropometrics were measured Results Comparing the neurodevelopment at the age of 24–30 months, using the DP-3 methodology of the children in the sample with values, measured during the validation of the questionnaire, a statistically significant difference was found in all areas. Other significant factors influencing the neurodevelopment were: the age of parents, the number and duration of the infections of the digestive tract, the number of severe infections of the respiratory system, and the child’s weight at 1 year. Conclusion Attention must be paid to the factors influencing neurodevelopment of children with family history of allergy because of the increased risk of delay in this vulnerable group.

The Bessarabian (Sarmatian) serpulid bioherms – an indicator of specific climatic conditions (Topola Formation, Northeastern Bulgaria)

Eight Bessarabian (Sarmatian) serpulid bioherms located among aragonite sediments of the Topola Formation in section Zelenka (Northeastern Bulgaria) have been studied to elucidate their macro- and microscopic characteristics. It is concluded that these bioherms were formed under identical arid climatic conditions as the associated aragonite sediments.

Pollen-based paleoclimate reconstructions of Beloslav Lake (Northeastern Bulgaria) during the last 6000 years using modern analog technique (MAT)

The aim of the present study is to reconstruct the palaeoclimate variables in the Beloslav Lake Region (Northeastern Bulgaria) during the last 6000 years, based on the pollen analysis from lacustrine core Bel-1 and using modern analog technique (MAT). Pollen data was used for reconstructions of four parameters: average annual temperature, average temperature of the warm and cold half-year and average annual precipitation.