Biodiversity Research in Bulgaria

A special issue of Diversity (ISSN 1424-2818). This special issue belongs to the section "Biogeography and Macroecology".

Deadline for manuscript submissions: closed (15 December 2022) | Viewed by 15474

Special Issue Editors

Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences (IBER-BAS), Sofia, Bulgaria
Interests: purification, biochemical analysis and production of native and recombinant proteins; molecular diagnostics of population and species structure; bioinformatic sequences database analysis
Special Issues, Collections and Topics in MDPI journals
Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Interests: molecular biology and molecular taxonomy; bioinformatic sequences database analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

With a total of 112 species on the international registers of endangered taxons, Bulgaria has rich biological diversity, which is subject to the impacts of a variety of threats caused by human activity and natural processes that occur in ecosystems. Anthropogenic threats to terrestrial systems include construction activities, infrastructure projects, resource extraction, agricultural intensification/extensification, illegal logging, environmental pollution, direct extermination/exploitation, genetic erosion, introduction of alien invasive species and climate change.

This Special Issue of Diversity aims to publish original contributions addressing questions of importance in biodiversity and related fields from Bulgaria. We welcome manuscripts conveying novel experimental findings that would advance the understanding of impact of activities on biodiversity; impact of threats on ecosystems and biodiversity; establishment of a database on species; establishment of the status of vegetation in particular areas and data on the status of environmental components and biodiversity. Manuscripts reporting the development or testing of novel taxons are also welcome.

Dr. Peter Hristov
Dr. Georgi Radoslavov
Dr. Boiko Neov
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Diversity is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (9 papers)

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Research

19 pages, 2217 KiB  
Article
Grassland Alterations Do Not Affect Breeding Success, but Can Explain Dietary Shifts of a Generalist Raptor Species
by Dimitar Atanasov Demerdzhiev, Dobromir Damyanov Dobrev and Zlatozar Nikolaev Boev
Diversity 2023, 15(3), 422; https://0-doi-org.brum.beds.ac.uk/10.3390/d15030422 - 13 Mar 2023
Cited by 1 | Viewed by 1080
Abstract
Habitat alteration is a widespread threat severely affecting large raptors because of their low density and the huge area they inhabit. In this study, we assessed whether human-driven habitat alterations mediated dietary shifts of apex predators, focusing on the Eastern imperial eagle ( [...] Read more.
Habitat alteration is a widespread threat severely affecting large raptors because of their low density and the huge area they inhabit. In this study, we assessed whether human-driven habitat alterations mediated dietary shifts of apex predators, focusing on the Eastern imperial eagle (Aquila heliaca). Following a bottom-up conception (before–after), we evaluated the effect of grassland change on the eagle’s dietary shift and breeding success. Land use patterns underwent a significant transformation over the study period, creating a large decrease in grasslands. The territories lost an average of 25.79% of their grasslands. Habitat alteration mediated dietary shifts, but had no reproductive consequences for eagles. Eagles became 1.90 times more likely to predate on northern white-breasted hedgehog and 1.62 times more likely to forage on white stork in the period after grassland alteration. The frequency of tortoises also increased, and they were 4.04 times more likely to be predated on in the years after transformation. Conversely, brown hare was 0.51 times less likely to be consumed in the grassland loss period, while this likelihood was 0.54 times lower for rodents and 0.64 times lower for the European souslik. Doves, meanwhile, were 2.73 times more likely to be predated on in the years following grassland destruction. We found that the presence and biomass of songbirds correlated negatively with the breeding success of eagles, and biomass supply from European souslik was negatively associated with breeding success, while the white stork’s presence and biomass resulted positively in more progeny. Diet diversity did not have an effect on the eagle’s reproduction. The responses of these eagles may vary across territories, depending on how they rank their prey, as the territory effect was a powerful factor shaping dietary shifts for this top predator. Our results offer new evidence of the link between habitat alteration, dietary shifts, and reproductive success, contributing to our understanding of the enigmatic mechanism through which an apex predator successfully adapts to large-scale land use pattern transformation by increasing dietary specialization. We recommend restoration of habitat complexity, including preservation of field margins, grassland patches with scattered small shrub formations, and grassland margins between medium-sized arable lands, promotion of measures for traditional grassland management through gradual grazing, and a ban on the use of shredders. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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11 pages, 2772 KiB  
Article
The European Ground Squirrel’s Genetic Diversity in Its Ancestral Land: Landscape Insights and Conservation Implications
by Yordan Koshev, Štěpánka Říčanová, Maria Kachamakova and Oldřich Říčan
Diversity 2023, 15(3), 365; https://0-doi-org.brum.beds.ac.uk/10.3390/d15030365 - 03 Mar 2023
Viewed by 1647
Abstract
The European ground squirrel is an endangered rodent whose populations are declining throughout its range. Only in Bulgaria, the genetic hotspot of the species, are some abundant populations still present. We employed 12 microsatellite loci in ten Bulgarian populations to look at population [...] Read more.
The European ground squirrel is an endangered rodent whose populations are declining throughout its range. Only in Bulgaria, the genetic hotspot of the species, are some abundant populations still present. We employed 12 microsatellite loci in ten Bulgarian populations to look at population structure, gene flow and recent bottlenecks. We found that the populations are in good condition in terms of heterozygosity, where values ranged from 0.55 to 0.78. However, the inbreeding index (FIS) was significant for most populations. A recent bottleneck was detected in only one population. Based on Bayesian clustering methods, the populations in Bulgaria were attributed to two groups, northern and southern, with admixture in the northern one. The AMOVA test between these groups showed no differentiation in genetic diversity. The mean value of FST was 0.184, which shows strong diversification among all populations. Hence, gene flow is probably limited. All these results indicate that Bulgaria is the main area to focus the efforts for conservation of the species by ensuring that the complex and rich genetic structure of Bulgarian populations is preserved. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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14 pages, 1427 KiB  
Article
Conservation of Host, Translocation of Parasites—Monitoring of Helminths during Population Reinforcement of the European Ground Squirrel (Spermophilus citellus)
by Maria Kachamakova, Yasen Mutafchiev, Pavel N. Nikolov and Yordan Koshev
Diversity 2023, 15(2), 266; https://0-doi-org.brum.beds.ac.uk/10.3390/d15020266 - 13 Feb 2023
Viewed by 1628
Abstract
Gastrointestinal helminth parasites can be transferred during conservation translocations and impact their outcome. The current study applied non-invasive coprological sampling to investigate the helminth infection rates and dynamics in translocated and resident European ground squirrels, during and after a population reinforcement. The FLOTAC [...] Read more.
Gastrointestinal helminth parasites can be transferred during conservation translocations and impact their outcome. The current study applied non-invasive coprological sampling to investigate the helminth infection rates and dynamics in translocated and resident European ground squirrels, during and after a population reinforcement. The FLOTAC method was calibrated and applied for the first time for the target species. In the studied coprological samples, helminth eggs belonging to Acanthocephala and Nematoda were found; the latter were morphologically identified as belonging to the families Capillariidae (Enoplida) and Trichostrongylidae (Strongylida) and superfamily Spiruroidea (Spirurida). The overall helminth prevalence and their diversity were higher in the donor colony compared to the resident one before the reinforcement. Pronounced seasonal dynamics in the parasite prevalence and diversity were observed, and their values were considerably lower in spring than in summer in both translocated and resident hosts. A year after the start of the translocation, the helminth prevalence and number of species detected in the reinforced colony had increased significantly. This is in accordance with epidemiological models and other empirical studies that predict a positive relationship between the population density of a host and the prevalence and species richness of parasites. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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15 pages, 4045 KiB  
Article
Seasonal Abundance, Density and Distribution of Cetaceans in the Bulgarian Black Sea Shelf in 2017
by Dimitar Popov, Marina Panayotova, Radoslava Bekova, Hristo Dimitrov and Galina Meshkova
Diversity 2023, 15(2), 229; https://0-doi-org.brum.beds.ac.uk/10.3390/d15020229 - 06 Feb 2023
Viewed by 1661
Abstract
Black Sea cetaceans are isolated and nominated as endemic subspecies listed in the IUCN Red List of Endangered species: the harbour porpoise and bottlenose dolphin as Endangered (EN) and the common dolphin as Vulnerable (VU). Studies of their distribution and abundance are scarce [...] Read more.
Black Sea cetaceans are isolated and nominated as endemic subspecies listed in the IUCN Red List of Endangered species: the harbour porpoise and bottlenose dolphin as Endangered (EN) and the common dolphin as Vulnerable (VU). Studies of their distribution and abundance are scarce but obligatory for assessment of their conservation status. Being highly mobile apex predators entails large variations in spatial and temporal distribution. Two vessel line–transect distance sampling surveys were conducted in 2017 in the Bulgarian shelf with the aim to estimate the density, abundance and distribution during spring and autumn. Results have revealed a shift from the coastal to offshore shelf of harbour porpoises with marked southern movement. Density of porpoises varied from 1.423 ind./km2 (CV = 25.4%) in spring to 0.576 ind./km2 (CV = 43.43%) in autumn. The density of common dolphins was also decreasing, from 0.391 ind./km2 (CV = 36.84%) to 0.088 ind./km2 (CV = 42.13%), which was more significant in offshore (0.031 ind./km2, CV = 58.04%) than in the coastal shelf (0.138 ind./km2, CV = 48.59%). Bottlenose dolphins had almost constant density in both seasons in the coastal shelf: 0.211 ind./km2 (CV = 52.15%) and 0.187 ind./km2 (CV = 52.13%) but a very low density in the offshore shelf in autumn: 0.042 ind./km2 (CV = 71.07%). The importance of existing NATURA 2000 sites for the harbour porpoise (BG0000621 Shabla-Ezerets, BG0000573 Kompleks Kaliaka, BG0001001 Ropotamo and BG0001007 Strandzha) and bottlenose dolphin (BG0000621 Shabla-Ezerets, BG0000573 Kompleks Kaliaka, BG0001501 Emona and BG0001001 Ropotamo) were confirmed. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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13 pages, 4713 KiB  
Article
Application of Fluctuating Asymmetry Values in Pelophylax ridibundus (Amphibia: Anura: Ranidae) Meristic Traits as a Method for Assessing Environmental Quality of Areas with Different Degrees of Urbanization
by Zhivko Zhelev, Ivelin Mollov and Stefan Tsonev
Diversity 2023, 15(1), 118; https://0-doi-org.brum.beds.ac.uk/10.3390/d15010118 - 15 Jan 2023
Cited by 2 | Viewed by 1515
Abstract
In this paper, we assess the environmental impact of urbanization in three freshwater biotopes, using the levels of fluctuating asymmetry (FA) in 10 meristic morphological traits in the Marsh Frog (Pelophylax ridibundus (Pallas, 1771)). Two of the studied biotopes are located in [...] Read more.
In this paper, we assess the environmental impact of urbanization in three freshwater biotopes, using the levels of fluctuating asymmetry (FA) in 10 meristic morphological traits in the Marsh Frog (Pelophylax ridibundus (Pallas, 1771)). Two of the studied biotopes are located in the boundaries of the city of Plovdiv (one in the central part, the other in a suburban residential area), and the third is located in the vicinity of the village of Orizare. Our working hypothesis is based on the assumption that urban and suburban sites are more severely affected by human activities than rural sites. However, according to our results, the population of P. ridibundus inhabiting Maritsa River in the central part of Plovdiv City, and that in the suburban zone, have found relatively good living conditions. Contrary to our expectations, the worst environmental conditions were observed in the rural zone, where anthropogenic stress related to intensive pastoral animal husbandry and crop farming was present. The absence of adult individuals in the rural site is also an indicator of unfavorable living conditions. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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13 pages, 9867 KiB  
Article
Morphology of Streptocara crassicauda and S. recta, with a Review of the Genus Streptocara (Nematoda: Acuariidae) and an Identification Key to Its Species
by Yasen Mutafchiev and Boyko B. Georgiev
Diversity 2023, 15(1), 67; https://0-doi-org.brum.beds.ac.uk/10.3390/d15010067 - 05 Jan 2023
Viewed by 1294
Abstract
The cosmopolitan genus Streptocara Railliet, Henry and Sisoff, 1912 (Nematoda: Acuariidae) comprises parasites of the upper alimentary tract of aquatic and, rarely, terrestrial birds. Two species of the genus Streptocara are redescribed from Bulgaria by means of light and scanning electron microscopy: Streptocara [...] Read more.
The cosmopolitan genus Streptocara Railliet, Henry and Sisoff, 1912 (Nematoda: Acuariidae) comprises parasites of the upper alimentary tract of aquatic and, rarely, terrestrial birds. Two species of the genus Streptocara are redescribed from Bulgaria by means of light and scanning electron microscopy: Streptocara crassicauda (Creplin, 1829), based on specimens from Larus genei, Larus minutus (Laridae) and Aythya ferina (Anatidae), and Streptocara recta (von Linstow, 1879) from Podiceps nigricollis (Podicipedidae). This is the first record of S. recta from Bulgaria. The host and distribution records of the species of the genus Streptocara are reviewed. Six species are recognised as valid. Streptocara crassicauda (Creplin, 1829), S. californica (Gedoelst, 1919), S. formosensis Sugimoto, 1930 and S. incognita Gibson, 1968, seem to be parasites well-adapted to birds of the family Anatidae (Anseriformes) and occasionally found in other birds, whereas S. recta (von Linstow, 1879) and S. longispiculata Gibson, 1968, are specialists of Podicipediformes and Gaviiformes, respectively. Streptocara indica Fotedar and Chishti, 1974, is recognised as a junior synonym of S. crassicauda, and Schistogendra oligopapillata Zhang and An, 2002, is considered as a junior synonym of Streptocara formosensis Sugimoto, 1930. An identification key to the species of the genus Streptocara is proposed. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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8 pages, 3803 KiB  
Communication
Fungi Associated with Messor Ants on the Balkan Peninsula: First Biogeographical Data
by Albena Lapeva-Gjonova, Sándor Csősz and Ferenc Báthori
Diversity 2022, 14(12), 1132; https://0-doi-org.brum.beds.ac.uk/10.3390/d14121132 - 17 Dec 2022
Viewed by 1378
Abstract
Ant nests’ relatively stable and long-lasting microhabitats present ideal living conditions for many uni- and multicellular organisms, whose relationships range from mutualistic to parasitic. Messor harvester ants inhabit arid and semi-arid open areas where their colonies consist of large numbers of individuals. Due [...] Read more.
Ant nests’ relatively stable and long-lasting microhabitats present ideal living conditions for many uni- and multicellular organisms, whose relationships range from mutualistic to parasitic. Messor harvester ants inhabit arid and semi-arid open areas where their colonies consist of large numbers of individuals. Due to the high number of other organisms associated with harvester ants, their nests can be defined as islands for unique biota. Despite significant progress in research on ant-associated fungi in Europe, little is still known about the recently described ectoparasitic fungus Rickia lenoirii Santamaria, 2015 (Laboulbeniales), found on two species of ants of the genus Messor. Here we report for the first time the occurrence of the ectoparasitic ant-associated fungus R. lenoirii from three countries (Albania, Bulgaria, and continental Greece) and multiple localities in the Balkans. The fungus was detected on four ant host species—Messor structor (Latreille, 1798), M. wasmanni Krausse, 1910, M. hellenius Agosti & Collingwood, 1987, and M. mcarthuri Steiner et al., 2018 with the latter two representing new host records. Furthermore, spores of the widespread endoparasitic fungus of ants, Myrmicinosporidium durum Hölldobler, 1933 (Blastocladiomycota), were reported for the first time in Messor structor (Bulgaria). Images of the ant-associated Rickia lenoirii taken with a scanning electron microscope, a comparison with R. wasmannii, and a distribution map are also presented. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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12 pages, 6343 KiB  
Article
Characterisation of Macroinvertebrate Communities in Maritsa River (South Bulgaria)—Relation to Different Environmental Factors and Ecological Status Assessment
by Emilia Varadinova, Lidia Sakelarieva, Jiyoung Park, Miroslav Ivanov and Violeta Tyufekchieva
Diversity 2022, 14(10), 833; https://0-doi-org.brum.beds.ac.uk/10.3390/d14100833 - 04 Oct 2022
Cited by 4 | Viewed by 1491
Abstract
A survey of the macrozoobenthos communities in the Maritsa River (South Bulgaria) was carried out in the summer of 2021. Benthic samples were collected and physicochemical parameters (water temperature, pH, conductivity, dissolved oxygen and nutrients) were measured at 15 sites located on the [...] Read more.
A survey of the macrozoobenthos communities in the Maritsa River (South Bulgaria) was carried out in the summer of 2021. Benthic samples were collected and physicochemical parameters (water temperature, pH, conductivity, dissolved oxygen and nutrients) were measured at 15 sites located on the main river and its tributary system. The studied sites belonged to different river types and characterised the diversity of the ecological conditions—from unaffected to anthropogenically influenced river stretches. In addition, data from a study conducted in the summer of 2020 were used to analyse species–factor interactions in the river ecosystems and to assess the bio-indicative potential of the aquatic invertebrates. The dynamics of the taxonomic composition and abundance of the macrozoobenthos were analysed in relation to environmental factors. The physicochemical conditions of the water environment changed during the period of high water, which led to a reduction in the composition of the macrozoobenthos. Plecoptera and Trichoptera decreased in richness and abundance downstream and under human impacts. Ephemeroptera and Chironomidae were permanently present along the whole river. Oligochaeta increased in the lower river reaches and at sites with a greater amount of organic matter. The ecological status determined by the macrozoobenthos varied from high (site 1) to good, moderate and bad (site 13) at the studied sites. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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12 pages, 6642 KiB  
Communication
Microsatellite Genotyping of Two Bulgarian Sheep Breeds
by Tsonka Odjakova, Pavel Todorov, Georgi Radoslavov and Peter Hristov
Diversity 2022, 14(3), 210; https://0-doi-org.brum.beds.ac.uk/10.3390/d14030210 - 11 Mar 2022
Cited by 4 | Viewed by 2612
Abstract
The aim of this study was to compare the genetic structure and genetic diversity of two Bulgarian sheep breeds. A total of 41 individuals from a modern Bulgarian sheep population (Rhodopean Tsigai, RT) and 46 representatives of a local Bulgarian sheep population (Middle [...] Read more.
The aim of this study was to compare the genetic structure and genetic diversity of two Bulgarian sheep breeds. A total of 41 individuals from a modern Bulgarian sheep population (Rhodopean Tsigai, RT) and 46 representatives of a local Bulgarian sheep population (Middle Rhodopean Sheep, MRS) were investigated based on 12 STR (short tandem repeat, also known as microsatellite) markers. In total, 121 alleles were found in the two populations using 12 microsatellite loci. The mean number of alleles, the effective number of alleles, and the polymorphism information content (PIC) values per loci were 10.08, 4.96, and 0.73, respectively. When comparing the allelic diversity across the populations, the highest Na was observed in the MRS breed (10.58 ± 0.87), while the value of this parameter in the RT breed was 9.58 ± 0.71. The largest genetic diversity was found at locus INRA005 with 14.5 alleles and the smallest polymorphism was noted for locus ETH152 with 5.5 alleles. The level of observed heterozygosity was in the range of 0.60 to 0.860. The expected heterozygosity level range was 0.62 to 0.87. When 12 microsatellite loci were compared, the INRA005 locus showed the highest level of genetic variability. Using Nei’s standard genetic distance, the observed genetic distance between the RT and MRS breeds was 0.103. Both sheep breeds demonstrated mixed genetic profiles based on the studied microsatellite markers. The clustering obtained by STRUCTURE analysis showed that the MRS breed is a more homogenous population, whereas the RT breed is more heterogenous. Full article
(This article belongs to the Special Issue Biodiversity Research in Bulgaria)
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