Nikolay Natchev

Nikolay Natchev
Konstantin Preslavsky University of Shumen · Department of Biology

prof. doc. rer. nat. Shumen University

About

97
Publications
30,810
Reads
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456
Citations
Citations since 2016
59 Research Items
354 Citations
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Introduction
I am working as an advisor of the Management board of the Road Infrastructure Agency in Bulgaria. Currently I am also employed as a full professor at the Shumen University and as associate at the Department of Integrative Zoology at Vienna University. At the moment I had limited my laboratory activities and concentrate on field surveys and documentaries production.
Additional affiliations
May 2017 - present
Konstantin Preslavsky University of Shumen
Position
  • Professor (Full)
September 2013 - present
Konstantin Preslavsky University of Shumen
Position
  • Professor (Associate)
Description
  • Mapping and Geographic Information Systems in Ecology; Human anatomy; Anthropology; Ecological monitoring; Ethology; Evolutionary morphology;
September 2011 - July 2013
Sofia University "St. Kliment Ohridski"
Position
  • Professor (Assistant)
Description
  • Zoology of the Vertebrates

Publications

Publications (97)
Article
The accumulation of microplastics in the world oceans is one of the main global problems of the modern world. The Black Sea is the main source of seafood for people from several countries, including Bulgaria. The pollution of the Black sea is a result of various factors, especially anthropogenic. The aim of this study was to determine the presence...
Article
Full-text available
In the present study, we report an early start of the breeding activities in the population of the Agile frog (Rana dalmatina) from the Natura park "Shumensko Plato" (NE-Bulgaria). In 2021 the first frogs entered the water on 09.02, and several egg clutches were observed the next day. According to our long-term monitoring, the start of the breeding...
Article
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The advanced snakes (Alethinophidia) include the extant snakes with a highly evolved head morphology providing increased gape and jaw flexibility. Along with other physiological and morphological adaptations, this allows them to immobilize, ingest, and transport prey that may be disproportionately large or presents danger to the predator from bites...
Article
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The present study is a review of the herpetofauna of the sourtheastern part of the Black Sea Coast and Strandzha Nature Park. A total of thirty nine species were recorded for both regions (12 amphinian species, 27 - reptiles), of which two newt species (Lissotriton vulgaris, Triturus ivanbureshi), ten species of anurans (Bombina bombina, B. variega...
Article
Full-text available
This paper presents a study on the microbial status of different fish species and their habitats in the Bulgarian Black Sea area. The samples were collected in the period of January 2021 until March 2021. The fish species we used in this study were Black Sea turbot ( Scophthalmus maximus ), round goby ( Neogobius melanostomus ), shore rockling ( Ga...
Article
Full-text available
The present study reports on the determination of the antimicrobial activity of lactic acid bacteria (LAB) isolated from the Black sea mussel Mytilus galloprovincialis Lamarck, 1819. The samples were collected in the period of August 2018 until March 2021. The BIOLOG system was used for microbiological determination. From the mussel M. galloprovinc...
Article
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Citation: Ignatova-Ivanova T, Ibryamova S, Bachvarova D, Salim S, Valkova S, Simeonova Y, Dimitrov D, Ivanov R, Chipev N, Natchev N (2022) Determination of the antimicrobial activity of lactic acid bacteria isolated from the Black sea mussel Mytilus galloprovincialis Lamarck, 1819. Pharmacia 69(3): 637-644. https://doi. Abstract The present study r...
Article
Full-text available
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...
Article
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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...
Article
Full-text available
The development of genomics in recent years has led to updates in the taxonomy of many terrestrial vertebrates. Following the most recent taxonomic revisions (Dufresnes et al., 2019a, b) of the anuran family Pelobatidae Bonaparte, 1850 (genus Pelobates Wagler, 1830), three species of spadefoot toad are now recognised on the territory of Bulgaria: P...
Article
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The main goal of the present study was to investigate the impact of the state of the environment on the microbiota of the wedge clam Donax trunculus (Linnaeus, 1758) from the region of Arkutino (Bulgarian Black Sea aquatory). The species Enterococcus hirae was isolated during the summer (from May to August). The species P. mendocina prefers the war...
Article
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Erhard’s Wall Lizard, Podarcis erhardii (Bedriaga, 1882), is an endemic reptile species of the Balkan Peninsula. It is distributed from southern Serbia through North Macedonia, Albania, southern Bulgaria, and Greece, including the Aegean archipelago. The group of wall lizards of the genus Podarcis (Wagler, 1830) in Europe currently consists of more...
Chapter
Little is known regarding the significance for local people of peri-urban national parks as recreational areas. The main goal of the present article is to evaluate the social impact and importance of peri-urban parks for visitors as a green space for outdoor recreation. For this investigation on-site, face-to-face interviews were conducted. The mai...
Article
Full-text available
The Xerotyphlops vermicularis (Merrem, 1820) complex represents small, burrowing snakes that occur from the Balkan Peninsula to Afghanistan and generally they are mostly observed during the springtime. In the present study, we report new records of this snake (10 individuals observed) from Elenite village in coastal Bulgaria. According to current k...
Article
The "white sand mussels" are edible bivalves inhabiting the littoral shores usually buried in the sand. Тhey are invasive species for the Bulgarian waters of the Black Sea. The samples for this study were collected from different points on the northern and southern Black Sea Bulgarian coast in the period January 2020 to December 2020. The study of...
Article
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The Bulgarian Bent-toed Gecko (Mediodactylus danilewskii Strauch, 1887) is one of the two species of geckos inhabiting the territory of Bulgaria. In the recent years, new information on its distribution was published and big amount of data were collected. We organized an information platform for sharing data on the biology and live-range of M. dani...
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We present data on the stomach contents and the gross morphology of the fat body in Agile Frogs (Rana dalmatina) from a pond which is an object of a long-termed monitoring. We also provide information on the diet of one female of Lissotriton vulgaris. All of the specimens were found dead during the mating season, when sudden snowfalls and depressio...
Article
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This scientific note reports on the recently detected presence of the Eurasian beaver (Castor fiber L. 1758) on the territory of Bulgaria. The species was previously a part of the Bulgarian fauna, however it disappeared from the territory of the country more than 150 years ago. Currently, one site in North Bulgaria was an object of long term monito...
Article
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There are many observations of unusual amplexus in anurans (e.g., interspecific, holding of artificial objects, and with dead specimen - both inter and intra specific, etc.) (Waterstrat et al., 2008; Mollov et al., 2010; Sodre et al., 2014; Müller, 2016; Shin et al., 2020). The price for such behaviour, however, is a waste of resources: time, energ...
Article
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The study of the feeding mechanisms in vertebrates requires an integrative approach since the feeding event consists of a chain of behaviors. In the present study we investigated the food uptake behavior in different ontogenetic stages in the Danube crested newt (Triturus dobrogicus). We focused on the coordination in the kinematics of the elements...
Article
Full-text available
The study of the feeding mechanisms in vertebrates requires an integrative approach since the feeding event consists of a chain of behaviors. In the present study we investigated the food uptake behavior in different ontogenetic stages in the Danube crested newt (Triturus dobrogicus). We focused on the coordination in the kinematics of the elements...
Article
Full-text available
Data on the diet for lizards in the genus Mediodactylus are relatively scarce, but they are known to feed on generally soft bodied or small arthropods in the order Diptera, Hymenoptera, Lepidoptera, Coleoptera, Araneae, and the suborder Heteroptera (Düşen et al. 2017. ISEAB, Minsk, Belarus. 508 pp.; Mollov and Boyadzhiev 2018. Ecolog. Balkan. 10:25...
Article
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The Agile Frog (Rana dalmatina) is one of the anurans species inhabiting the Nature Park "Shumensko Plato" (north-eastern Bulgaria). In 2019 and 2020 we studied the general ecology of the population in the Park and in particular the breeding activity of the frogs. During our survey we registered extension of the breeding season and we also report o...
Article
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Recently, the phylogeny of the "Kotschy's gecko" (Mediodactylus kotschyi Steindachner,1870) was revised, and the Black sea populations were distinguished as a new species-the Bulgarian Bent-toed Gecko (Mediodactylus danilewskii Strauch, 1887). This species was never reported for the inland of north Bulgaria (except for one already extinguished popu...
Article
Full-text available
Hydrobiological monitoring and assessment of the ecological status of Dalgachka River and an ecological potential assessment based on abiotic metrics of Ovcharovo dam, was performed in the region of Protected Site "Ovcharovo" in 2017 and 2018. The ecological status assessment was based on the macroinvertebrate community as a bio-indicator and the m...
Article
Full-text available
In the present study we present the results from antifungal activity of Lactic Acid Bacteria, isolated from M. galloprovincialis Lam. from the Bulgarian Black Sea aquatory. The Black Sea mussel (M. galloprovincialis Lam.) is in fact the only marine species grown as aquaculture in the Bulgarian section of the Black Sea. The mussels have an exception...
Chapter
Turtles are one of the oldest known sauropsid orders that appeared about 240 million years ago. Within the vertebrates, they have evolved the most unusual body plan, with most of their body inside a protective box made of bone and keratin. This peculiar morphology has persisted since the late Triassic, but has allowed them to adapt to very diverse...
Article
Full-text available
Dolichophis caspius is the longest snake in Bulgaria and to date, only two individuals with a total length > 200 cm have been captured in Bulgaria (Stojanov et al. 2011. Die Amphibien und Reptilien Bulgariens. Chimaira, Frankfurt am Main. 586 pp.). One of the specimens was a female measuring 202 cm total length, captured at Gorno Lukovo village in...
Article
Cranial kinesis refers to intracranial movements in the vertebrate skull that do not concern the jaw joint, the middle ear or the hypobranchial skeleton. Different kinds of cranial kinesis have been reported for lizards, including mesokinesis, metakinesis, amphikinesis (simultaneous mesokinesis and metakinesis) and streptostyly. Streptostyly is con...
Article
Full-text available
Anthropogenic activities cause environmental pollution and alter biogeochemical cycles. Soils in cities and their vicinity are exposed to different pollutants. Nature Park Shumen Plateau is a protected area situated in the proximity of Shumen (Bulgaria). The aim of this research was to compare elemental composition of surface soil samples from Natu...
Article
Full-text available
Little is known regarding the significance for local people of peri-urban national parks as recreational areas. The main goal of the present article is to evaluate the social impact and importance of peri-urban parks for visitors as a green space for outdoor recreation. For this investigation on-site, face-to-face interviews were conducted. The mai...
Article
Full-text available
We developed a combined method for marking and identification of specimens of the nose-horned viper (Vipera ammodytes). The method operates on three levels and is very reliable. The first recognition level is based on relatively large numbers, painted on the side of the snakes. We discovered that the markings last for up to five months and even sha...
Article
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In a four-year monitoring period, numerous permanent and temporary water basins on the territory of the Habitat Protected Site BG0000382 and the Nature Park "Shumensko Plato" (NE Bulgaria) were identified as possible habitats for amphibians. We inspected the water bodies for presence of Urodelas, included in the inventory documentation of the prote...
Article
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Commercial trade in Pond sliders (Trachemys scripta scripta and T. s. elegans) is the most important factor responsible for their wide distribution in ecosystems where they are non-native. Pond sliders have been very popular pets in Bulgaria since 1990 and can be still obtained commercially for several Euros from pet shops or via the Internet. Ther...
Article
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Most of the studies dealing with the Snake-eyed skink (Ablepharus kitaibelii) treat predominantly aspects of the distribution and taxonomy of the species. In the present study we provide information concerning the mechanism of hatching in the Snake-eyed skink and the dimensions of the hatched specimens. We collected data from wild animals, as well...
Article
Full-text available
We developed a combined method for marking and identification of specimens of the nose-horned viper (Vipera ammodytes). The method operates on three levels and is very reliable. The first recognition level is based on relatively large numbers, painted on the site side of the snakes. We discovered that the markings last for up to five months and eve...
Article
Full-text available
The European Pond Turtle is a predominantly aquatic species, generally assumed to feed exclusively under water by using hydrodynamic mechanisms. We analysed the kinematics of the aquatic food uptake and food transport by using high-speed videos with 500 fps. The analyses revealed that subadult E. orbicularis use compensatory suction for food uptake...
Article
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Increasing attention has been paid recently to soil pollution. The aim of this study was to evaluate the ecological risk of soils collected from Nature Park Shumen Plateau (Bulgaria) (NP) using physico-chemical and cytogenetic approaches (pH analysis, analysis of the content of heavy metals included in Bulgarian soil pollution standards, and Allium...
Article
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The Veleka River in SE Bulgaria is amongst the northernmost localities of coexistence of Emys orbicularis and Mauremys rivulata, the two native freshwater turtles. This linear structure provides a rare opportunity to study whether the species separate across a seemingly similar habitat. In 2010–2014, we sampled by boat 5.5 km of the river near its...
Article
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The Fifth International Symposium on Emys orbicularis and the other European Freshwater Turtles was held in Kiten, Bulgaria, on 19–21 August 2015. It continued the tradition of international collaboration and exchange of knowledge related to the chelonians. The resultant proceedings combine 22 papers presented in the program of the symposium. They...
Article
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Although illegal wildlife trafficking is a global threat to biodiversity and a key reason for the decline of turtle populations, there are insufficient measures in place to combat it. Prompted by the recent seizure of over 1,300 European Pond Turtles in a single raid, experts on biology and conservation of chelonians discussed experiences on this a...
Poster
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Snakes are able to immobilize, ingest, transport, and swallow prey of relatively large size as well as dangerous items such as other predators, hard biting, spiny, or toxic prey. Various incidents have been reported of snakes failing to complete the prey consumption process and being injured or killed during different phases of the feeding. Here we...
Article
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We report for the first time on the occurrence of tail bifurcations in the snake-eyed skink (A. kitaibelii). This morphological anomaly was identified during a four-year monitoring program conducted in a herpetological hot-spot at Pastrina hill (northwestern Bulgaria). From a total of 415 captured specimens, four animals (0.96%) showed symmetrical...
Article
Full-text available
In the present study, we investigated and documented the morphology of the male copulatory organs (hemipenes) in fifteen wide-ranging snake species. The species represent four families (Boidae, Colubridae, Lamprophiidae, and Viperidae) and ten genera. We applied the same preparation techniques for all species, successfully everting and expanding th...
Article
The study reports data from a four year monitoring of the herpetofauna-vehicle collisions in the region of Burgas city, Bulgaria. The investigated region is inhabited by 26 species of amphibians and cold blooded amniotes. The traffic induces road mortality in some of the investigated species. We provide information concerning the hot spots with inc...
Article
Full-text available
The study reports data from a four year monitoring of the herpetofauna-vehicle collisions in the region of Burgas city, Bulgaria. The investigated region is inhabited by 26 species of amphibians and cold blooded amniotes. The traffic induces road mortality in some of the investigated species. We provide information concerning the hot spots with inc...
Data
The study reports data from a four year monitoring of the herpetofauna-vehicle collisions in the region of Burgas city, Bulgaria. The investigated region is inhabited by 26 species of amphibians and cold blooded amniotes. The traffic induces road mortality in some of the investigated species. We provide information concerning the hot spots with inc...
Article
Full-text available
Dice snakes (Natrix tessellata, Laurenti, 1768) inhabit oligohaline and brackish waters along the Bulgarian Black Sea coast, where they often forage at sea. Under these conditions, this species should tolerate highly variable blood plasma sodium concentrations for extended time periods, but the effect of high sodium concentrations to blood cell mor...
Article
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In a previous study, the authors had predicted that the local green frog population had developed adaptations to live and breed in mixoligohaline waters, however the registered in 2010 mass migration of the adults into the sea near the Shablenska Tuzla lagoon was an isolated event, conditioned by the correlated impact of defined climatic factors. T...
Article
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A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch’s newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoqu...
Article
Full-text available
The current paper reports a new location of the Blotched snake (Elaphe sauromates) in south-east Bulgaria. On 14.05.2016 we found a dead adult specimen in the east part of the town Aytos. To date the species was not recorded for the locus. This is the first record of the Blotched snake in urbanized area and we provide a discussion concerning the di...
Article
Full-text available
The Raccoon dog (Nyctereutes procyonoides Gray, 1834) is an invasive species which was first recorded for the Bulgarian fauna in 1968. To date, data concerning the distribution of the species in Bulgaria are rather scarce and often provided by non specialists (mostly local fishermen and hunters). The present note includes information concerning the...
Article
Full-text available
Within the scope of the present study a field survey in the area of “Strandzha” Natural Park in south-east Bulgaria was carried out. The main goal of the investigation was to gain more detailed information on the diet of the European otters (Lutra lutra) that inhabit the park. As indicators for the presence of the mustelids a set of standard proced...
Article
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Almost all extant testudinids are highly associated with terrestrial habitats and the few tortoises with high affinity to aquatic environments are found within the genus Manouria. Manouria belongs to a clade which forms a sister taxon to all remaining tortoises and is suitable as a model for studying evolutionary transitions within modern turtles....
Article
To date, the data published on the occurrence of the fire-bellied toad (Bombina bombina) and yellow-bellied toad (B. variegata) in the region of the Natural Park “Shumensko plato” (SE Bulgaria) are controversial. The species are included in the inventory of the protected territory, but none of them has been reported since 1934. In the range of this...
Article
Full-text available
To date, the data published on the occurrence of the fire-bellied toad (Bombina bombina) and yellow-bellied toad (B. variegata) in the region of the Natural Park “Shumensko plato” (SE Bulgaria) are controversial. The species are included in the inventory of the protected territory, but none of them has been reported since 1934. In the range of this...