В статията се представят два от трите вида хамстери които обитават България - Обикновения хамтсте... more В статията се представят два от трите вида хамстери които обитават България - Обикновения хамтстер (Cricetus cricetus) и Дорбруджанския/черногръд хамстер (Mesocricetus newtoni).
The article presents two of the three species of hamsters that inhabit Bulgaria - the Common Hamster (Cricetus cricetus) and the Dorbrudzhan/Black-breasted/Romanian Hamster (Mesocricetus newtoni).
Declines in area of occupancy and habitat quality are ongoing for the European ground squirrel (S... more Declines in area of occupancy and habitat quality are ongoing for the European ground squirrel (Spermophilus citellus) is species across its range, and are predicted to increase in upcoming decades. Ongoing habitat destruction has been recorded in new EU member states such as Romania, Bulgaria and also in Serbia, the latter is also expected to face increased grassland destruction in the near future. Especially in EU member states, agricultural intensification continues to negatively affect European Ground Squirrel habitats. Further agricultural intensification is suspected to cause additional decline in extent of occurrence and quality of habitat within the next 10 years. Especially in the western part of the range, high levels of isolation of European Ground Squirrel populations have negatively affected the species: in Hungary, populations are frequently decreasing without habitat elimination or without the size of the habitats decreasing. Many of the large populations are not protected, and the species is generally highly dependent on the anthropogenic management of its habitats, primarily by livestock grazing. Also, genetic depletion of fragmented populations has been observed in Central Europe. Overall, known or suspected population reduction in the past, and suspected future population reduction is likely to be over 50%. Although most of the contractions happened outside of EU member states (Ukraine and Moldova), and the EU countries share the largest and most stable populations of the species (Hungary, Romania and Bulgaria), the assessment for EU27 is the same as for Global assessment, as there are predictions of large future declines in suitable habitat in the region due to climate change, and this could cause population declines of 50%, therefore it is precautionarily listed as Endangered. The species is assessed as EN A3c for both European and EU27 regions.
The house mouse is the best-studied mammal species after humans, yet our understanding of its evo... more The house mouse is the best-studied mammal species after humans, yet our understanding of its evolutionary history remains incomplete. Here, we focused on the colonisation of Europe by two subspecies and formation of a hybrid zone between them. We carried out a large-scale study of ~7000 mice sampled across an area embracing an ~900 km long portion of the zone, supplemented with cytochrome b and D-loop sequencing of ~1200 individuals collected worldwide. We demonstrate that the course of the mtDNA contact front is intricate and highly discordant with the consensus front for autosomal and X-linked markers, suggesting that local snapshots of mtDNA introgression may be misleading when treated in isolation. While multiple unrelated M. m. domesticus haplotypes occur in the zone area, the diversity of M. m. musculus haplotypes is limited. Moreover, we uncovered a vast region of domesticus introgression into musculus territory in northern areas and showed this introgression is unlikely to be driven by positive selection. We consider two previously published hypotheses explaining this phenomenon and put forth an alternative scenario assuming associations between mice and humans in northern Europe during the Nordic Bronze Age and subsequent zone movement associated with the expansion of Balto-Slavic peoples.
Mink farming has seen a resurgence in Bulgaria since 2013, and this has led to a high risk of Ame... more Mink farming has seen a resurgence in Bulgaria since 2013, and this has led to a high risk of American mink escaping and establishing feral populations. The largest active commercial farm in the country has a capacity of nearly 130,000 animals. The aims of this study were to gather first-hand evidence of the presence of mink in the wild around the farm, assess their level of establishment, and document the native species and local communities for future impact assessment. Surveys were conducted using camera traps within a 3.7 km radius around the farm in the period 2020–2021 at ten stations with 1943 realised trap-nights. Some early signs of the establishment of the American mink in Bulgaria were documented. A large number of registrations was made, as frequently as the Eurasian otter and golden jackal and more frequently than other mustelids in the study area. Mink were observed throughout the two-year study, and escaped mink have been registered in the region as early as 2017. These factors are interpreted as signs of the early stages of establishment. When considering environmental, economic, public health, and social factors, we recommend that mink farming should be banned in Bulgaria and further monitoring and management actions must be undertaken for the individuals in the wild.
A review on the composition of the small mammals in Vrachanska Planina Mts. was completed using p... more A review on the composition of the small mammals in Vrachanska Planina Mts. was completed using published and author's data. A total of 27 species occur within the territory. All of the species found are typical for the region. The species with the highest conservation status, the European ground squirrel Spermophilus citellus, disappeared from the region in the early 1950s. In the last years activities on its recovery were carried out. We analyze the threats for the small mammals and propose conservation activities to improve their conservation status.
Научно-популярна статия за европейския лалугер (Spermophilus citellus) в списание "Лов и риболов"... more Научно-популярна статия за европейския лалугер (Spermophilus citellus) в списание "Лов и риболов". В статията се коментира намаляването на популацията на лалугера и броя на колониите в България и причините за това. //
Popular science review about the European ground squirrel/ souslik (Spermophilus citellus) in the journal "Lov i Ribolov". The article comments on the reduction of the european souslik population and the number of colonies in Bulgaria and the reasons for this.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Abstract The spatial behaviour of 47 European ground squirrels (Spermophilus citellus) was invest... more Abstract The spatial behaviour of 47 European ground squirrels (Spermophilus citellus) was investigated through radio-collars in the frame of a conservation project for population reinforcement in south-eastern Bulgaria. For the first time both translocated and resident individuals were collared. After the release, each individual’s movement was followed hourly through triangulation during the day and the sleep sites were localised by radio-tracking in the evening. The results showed that the translocated individuals had much larger territories in comparison with the residents. The males and the adults were significantly more mobile than the females and juveniles. Considerable relocation was observed in more than one third of the translocated individuals between the 5th and the 10th day after the release. The main reason for death was predation. The survival of the translocated individuals at the end of the first active season after the translocation was 79%. Recommendations for future Spermophilus citellus conservation translocations were drawn.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Relation between body mass and home range size (HRS) was studied in two small mammals' species Cl... more Relation between body mass and home range size (HRS) was studied in two small mammals' species Clethryonomys glareolus and Apodemus sylvsticus inhabiting the same habitat. The relation between HRS and the body mass of individuals of both species is thought to be regression expressed in the following way: logy = a + b*logx. The regression equations for both sexes and different age groups during the period of investigation were worked out. Analysis of equation coefficients revealed indirectly the influence of Apodemus flavicollis on territorial behavior of Clethrionomys glareolus.
The European ground squirrel (Spermophilus citellus) is an endangered species and typically inhab... more The European ground squirrel (Spermophilus citellus) is an endangered species and typically inhabits steppes and open woodland of Central Europe and the Balkans. Knowledge about its distribution and status in the southern part of its range is scanty. Distribution of the species in Bulgaria over two periods (1950-1989 and 1990-2008) and recent status of 90 colonies in three model regions (mountain region, Sofia field and Thracian valley) are evaluated in the paper. Data on 254 UTM squares inhabited by S. citellus during the first period and 212 UTM squares inhabited during the second period were available, but these data could not be compared because of the different survey methods used. S. citellus colonies in southwestern Bulgaria may be already extinct and population decline is supposed to take place at the southwestern periphery of the species' distribution range. About 30% out of 90 investigated colonies have disappeared, 28% are vulnerable and only 42% are stable. The biggest part of the extinct colonies was found in the Sofia field and Mountain region. Pastures are the most frequently occupied land use type (72%) in Bulgaria and major threats for the S. citellus population include pasture degradation, building up, intensification of agriculture, interruption of biological corridors and flooding. The S. citellus population in Bulgaria has been probably declining and current status of the species is unfavourable. The S. citellus conservation status in Bulgaria should be enhanced and the species should be included in the new Red Book of Animals in Bulgaria in the category "vulnerable" and should be protected according to the national biodiversity legislation.
Distribution, connectivity, isolation and major threats to European ground squirrel (Spermophilus... more Distribution, connectivity, isolation and major threats to European ground squirrel (Spermophilus citellus) in Pazardzhik district have been investigated. We have found 55 colonies, ten of which were inactive. The biggest part (67.3%) of colonies occurred in lowlands up to 300 m. Probably the habitats around rivers Maritza, Topolnitza and Luda Yana represented dispersal corridors for the species. The average distance of active European ground squirrel colonies was 3.25±1.4 km and 5.95±2.37 km of inactive ones. The isolation (t =3.51, p<0.01, d.f.=53) and connectivity (t=4.07, p<0.01, d.f.=53) indices were significantly different between active and inactive colonies. The main cause for colonies extinction probably was the destruction of the natural dispersal corridors between colonies with high Isolation index. Probably this factor had a stronger influence on the colonies with small area and population density.
ABSTRACT This work presents novel data that has allowed us to propose an evolutionary model for t... more ABSTRACT This work presents novel data that has allowed us to propose an evolutionary model for the karyotype of the European ground squirrel (Spermophilus citellus, L. 1766) based on sex chromosome variants. Routine C- and G- banding, specific fluorochrome staining (CMA3, DAPI) and FISH experiments were used to characterize the pattern of chromosomal variation in populations of S. citellus in the Southeastern part of the Balkan Peninsula, the ancestral area of the species with the highest genetic diversity. The established diploid chromosome number of S. citellus is 2n = 40. All autosomes are biarmed: 12 pairs of large to small submetacentrics, 5 pairs of large to small subtelocentrics, one medium-sized and one small pair of metacentrics. Three different morphologies are observed for both X and Y chromosomes. The X chromosomes are classified as acrocentric, subtelocentric, or submetacentric. In most of the individuals studied, the Y chromosome was dot-like, with the exception of a few presenting small or medium-sized acrocentrics and metacentrics. Blocks of heterochromatin of different sizes were found in the centromeric regions of all autosomes and X chromosomes, while all Y chromosome variants appeared to be entirely heterochromatic. CMA3 fluorescence was bright in the majority of the C-positive regions and in the acrocentric X chromosome. These results were supported by DAPI staining, which showed that the CMA3-positive sites were DAPI-negative and approximately of the same distinct sizes. In situ hybridization with the (TTAGGG)n probe produced a staining typical of telomeric repeats at the edges of all chromosomes. Notably, the Y chromosome showed stronger accumulation of telomeric repeats than that observed on other chromosomes. The nature of the C-, G- and fluorochrome staining of the sex chromosomes of S. citellus suggested that the amplification of constitutive heterochromatin and the pericentric inversions were likely sufficient to explain the differences between the morphology of sex chromosome. The observed sex chromosome variability reinforces the differences among the populations of the S. citellus in the Southeastern part of the Balkan Peninsula and correlate with specific geographical areas. These will be further investigated in order to fully evaluate the adaptive value of chromosome rearrangements.
The European ground squirrel (Spermophiluscitellus) is a vulnerable species (IUCN) living in open... more The European ground squirrel (Spermophiluscitellus) is a vulnerable species (IUCN) living in open habitats of Central and South-eastern Europe. Translocations (introductions, reintroductions and reinforcements) are commonly used as part of the European ground squirrel (EGS) conservation. There are numerous publications for such activities carried out in Central Europe, but data from South-eastern Europe, where translocations have also been implemented, are still scarce. The present study summarises the methodologies used in the translocations in Bulgaria and analyses the factors impacting their success. Eight translocations of more than 1730 individuals were performed in the period 2010 to 2018. These included 4 reinforcements, 3 reintroductions and 1 introduction. Two of the translocations are still ongoing. Five of the completed six (83%) translocations were successful, although in two cases the number of individuals was critically low. The relatively higher success in Bulgaria than in Central Europe is probably due to using the gained experience. Most of the translocations (6) used a soft release approach. In 6 cases, the animals settled 100 to 720 metres away from the release site, implying management and protection of suitable habitat beyond the translocation area. In 7 of the translocations, the altitude between the donor colony and the release site varied from 470 to 1320 m which could have a hindering effect on the adaptation of animals due to the specific conditions in the mountains. The main reasons for failure are probably poorly selected and maintained habitats and bad climatic conditions (rainy and cool weather) during the translocation action. European funds are of critical importance for translocations, with only two translocations funded by other sources. Based on the gathered data, the current paper also gives some recommendations for improvement in translocation activities.
The European ground squirrel is an endangered rodent whose populations are declining throughout i... 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 ...
The European ground squirrel is an endangered rodent whose populations are declining throughout i... 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 Bul-garian populations is preserved.
В статията се представят два от трите вида хамстери които обитават България - Обикновения хамтсте... more В статията се представят два от трите вида хамстери които обитават България - Обикновения хамтстер (Cricetus cricetus) и Дорбруджанския/черногръд хамстер (Mesocricetus newtoni).
The article presents two of the three species of hamsters that inhabit Bulgaria - the Common Hamster (Cricetus cricetus) and the Dorbrudzhan/Black-breasted/Romanian Hamster (Mesocricetus newtoni).
Declines in area of occupancy and habitat quality are ongoing for the European ground squirrel (S... more Declines in area of occupancy and habitat quality are ongoing for the European ground squirrel (Spermophilus citellus) is species across its range, and are predicted to increase in upcoming decades. Ongoing habitat destruction has been recorded in new EU member states such as Romania, Bulgaria and also in Serbia, the latter is also expected to face increased grassland destruction in the near future. Especially in EU member states, agricultural intensification continues to negatively affect European Ground Squirrel habitats. Further agricultural intensification is suspected to cause additional decline in extent of occurrence and quality of habitat within the next 10 years. Especially in the western part of the range, high levels of isolation of European Ground Squirrel populations have negatively affected the species: in Hungary, populations are frequently decreasing without habitat elimination or without the size of the habitats decreasing. Many of the large populations are not protected, and the species is generally highly dependent on the anthropogenic management of its habitats, primarily by livestock grazing. Also, genetic depletion of fragmented populations has been observed in Central Europe. Overall, known or suspected population reduction in the past, and suspected future population reduction is likely to be over 50%. Although most of the contractions happened outside of EU member states (Ukraine and Moldova), and the EU countries share the largest and most stable populations of the species (Hungary, Romania and Bulgaria), the assessment for EU27 is the same as for Global assessment, as there are predictions of large future declines in suitable habitat in the region due to climate change, and this could cause population declines of 50%, therefore it is precautionarily listed as Endangered. The species is assessed as EN A3c for both European and EU27 regions.
The house mouse is the best-studied mammal species after humans, yet our understanding of its evo... more The house mouse is the best-studied mammal species after humans, yet our understanding of its evolutionary history remains incomplete. Here, we focused on the colonisation of Europe by two subspecies and formation of a hybrid zone between them. We carried out a large-scale study of ~7000 mice sampled across an area embracing an ~900 km long portion of the zone, supplemented with cytochrome b and D-loop sequencing of ~1200 individuals collected worldwide. We demonstrate that the course of the mtDNA contact front is intricate and highly discordant with the consensus front for autosomal and X-linked markers, suggesting that local snapshots of mtDNA introgression may be misleading when treated in isolation. While multiple unrelated M. m. domesticus haplotypes occur in the zone area, the diversity of M. m. musculus haplotypes is limited. Moreover, we uncovered a vast region of domesticus introgression into musculus territory in northern areas and showed this introgression is unlikely to be driven by positive selection. We consider two previously published hypotheses explaining this phenomenon and put forth an alternative scenario assuming associations between mice and humans in northern Europe during the Nordic Bronze Age and subsequent zone movement associated with the expansion of Balto-Slavic peoples.
Mink farming has seen a resurgence in Bulgaria since 2013, and this has led to a high risk of Ame... more Mink farming has seen a resurgence in Bulgaria since 2013, and this has led to a high risk of American mink escaping and establishing feral populations. The largest active commercial farm in the country has a capacity of nearly 130,000 animals. The aims of this study were to gather first-hand evidence of the presence of mink in the wild around the farm, assess their level of establishment, and document the native species and local communities for future impact assessment. Surveys were conducted using camera traps within a 3.7 km radius around the farm in the period 2020–2021 at ten stations with 1943 realised trap-nights. Some early signs of the establishment of the American mink in Bulgaria were documented. A large number of registrations was made, as frequently as the Eurasian otter and golden jackal and more frequently than other mustelids in the study area. Mink were observed throughout the two-year study, and escaped mink have been registered in the region as early as 2017. These factors are interpreted as signs of the early stages of establishment. When considering environmental, economic, public health, and social factors, we recommend that mink farming should be banned in Bulgaria and further monitoring and management actions must be undertaken for the individuals in the wild.
A review on the composition of the small mammals in Vrachanska Planina Mts. was completed using p... more A review on the composition of the small mammals in Vrachanska Planina Mts. was completed using published and author's data. A total of 27 species occur within the territory. All of the species found are typical for the region. The species with the highest conservation status, the European ground squirrel Spermophilus citellus, disappeared from the region in the early 1950s. In the last years activities on its recovery were carried out. We analyze the threats for the small mammals and propose conservation activities to improve their conservation status.
Научно-популярна статия за европейския лалугер (Spermophilus citellus) в списание "Лов и риболов"... more Научно-популярна статия за европейския лалугер (Spermophilus citellus) в списание "Лов и риболов". В статията се коментира намаляването на популацията на лалугера и броя на колониите в България и причините за това. //
Popular science review about the European ground squirrel/ souslik (Spermophilus citellus) in the journal "Lov i Ribolov". The article comments on the reduction of the european souslik population and the number of colonies in Bulgaria and the reasons for this.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Abstract The spatial behaviour of 47 European ground squirrels (Spermophilus citellus) was invest... more Abstract The spatial behaviour of 47 European ground squirrels (Spermophilus citellus) was investigated through radio-collars in the frame of a conservation project for population reinforcement in south-eastern Bulgaria. For the first time both translocated and resident individuals were collared. After the release, each individual’s movement was followed hourly through triangulation during the day and the sleep sites were localised by radio-tracking in the evening. The results showed that the translocated individuals had much larger territories in comparison with the residents. The males and the adults were significantly more mobile than the females and juveniles. Considerable relocation was observed in more than one third of the translocated individuals between the 5th and the 10th day after the release. The main reason for death was predation. The survival of the translocated individuals at the end of the first active season after the translocation was 79%. Recommendations for future Spermophilus citellus conservation translocations were drawn.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Relation between body mass and home range size (HRS) was studied in two small mammals' species Cl... more Relation between body mass and home range size (HRS) was studied in two small mammals' species Clethryonomys glareolus and Apodemus sylvsticus inhabiting the same habitat. The relation between HRS and the body mass of individuals of both species is thought to be regression expressed in the following way: logy = a + b*logx. The regression equations for both sexes and different age groups during the period of investigation were worked out. Analysis of equation coefficients revealed indirectly the influence of Apodemus flavicollis on territorial behavior of Clethrionomys glareolus.
The European ground squirrel (Spermophilus citellus) is an endangered species and typically inhab... more The European ground squirrel (Spermophilus citellus) is an endangered species and typically inhabits steppes and open woodland of Central Europe and the Balkans. Knowledge about its distribution and status in the southern part of its range is scanty. Distribution of the species in Bulgaria over two periods (1950-1989 and 1990-2008) and recent status of 90 colonies in three model regions (mountain region, Sofia field and Thracian valley) are evaluated in the paper. Data on 254 UTM squares inhabited by S. citellus during the first period and 212 UTM squares inhabited during the second period were available, but these data could not be compared because of the different survey methods used. S. citellus colonies in southwestern Bulgaria may be already extinct and population decline is supposed to take place at the southwestern periphery of the species' distribution range. About 30% out of 90 investigated colonies have disappeared, 28% are vulnerable and only 42% are stable. The biggest part of the extinct colonies was found in the Sofia field and Mountain region. Pastures are the most frequently occupied land use type (72%) in Bulgaria and major threats for the S. citellus population include pasture degradation, building up, intensification of agriculture, interruption of biological corridors and flooding. The S. citellus population in Bulgaria has been probably declining and current status of the species is unfavourable. The S. citellus conservation status in Bulgaria should be enhanced and the species should be included in the new Red Book of Animals in Bulgaria in the category "vulnerable" and should be protected according to the national biodiversity legislation.
Distribution, connectivity, isolation and major threats to European ground squirrel (Spermophilus... more Distribution, connectivity, isolation and major threats to European ground squirrel (Spermophilus citellus) in Pazardzhik district have been investigated. We have found 55 colonies, ten of which were inactive. The biggest part (67.3%) of colonies occurred in lowlands up to 300 m. Probably the habitats around rivers Maritza, Topolnitza and Luda Yana represented dispersal corridors for the species. The average distance of active European ground squirrel colonies was 3.25±1.4 km and 5.95±2.37 km of inactive ones. The isolation (t =3.51, p<0.01, d.f.=53) and connectivity (t=4.07, p<0.01, d.f.=53) indices were significantly different between active and inactive colonies. The main cause for colonies extinction probably was the destruction of the natural dispersal corridors between colonies with high Isolation index. Probably this factor had a stronger influence on the colonies with small area and population density.
ABSTRACT This work presents novel data that has allowed us to propose an evolutionary model for t... more ABSTRACT This work presents novel data that has allowed us to propose an evolutionary model for the karyotype of the European ground squirrel (Spermophilus citellus, L. 1766) based on sex chromosome variants. Routine C- and G- banding, specific fluorochrome staining (CMA3, DAPI) and FISH experiments were used to characterize the pattern of chromosomal variation in populations of S. citellus in the Southeastern part of the Balkan Peninsula, the ancestral area of the species with the highest genetic diversity. The established diploid chromosome number of S. citellus is 2n = 40. All autosomes are biarmed: 12 pairs of large to small submetacentrics, 5 pairs of large to small subtelocentrics, one medium-sized and one small pair of metacentrics. Three different morphologies are observed for both X and Y chromosomes. The X chromosomes are classified as acrocentric, subtelocentric, or submetacentric. In most of the individuals studied, the Y chromosome was dot-like, with the exception of a few presenting small or medium-sized acrocentrics and metacentrics. Blocks of heterochromatin of different sizes were found in the centromeric regions of all autosomes and X chromosomes, while all Y chromosome variants appeared to be entirely heterochromatic. CMA3 fluorescence was bright in the majority of the C-positive regions and in the acrocentric X chromosome. These results were supported by DAPI staining, which showed that the CMA3-positive sites were DAPI-negative and approximately of the same distinct sizes. In situ hybridization with the (TTAGGG)n probe produced a staining typical of telomeric repeats at the edges of all chromosomes. Notably, the Y chromosome showed stronger accumulation of telomeric repeats than that observed on other chromosomes. The nature of the C-, G- and fluorochrome staining of the sex chromosomes of S. citellus suggested that the amplification of constitutive heterochromatin and the pericentric inversions were likely sufficient to explain the differences between the morphology of sex chromosome. The observed sex chromosome variability reinforces the differences among the populations of the S. citellus in the Southeastern part of the Balkan Peninsula and correlate with specific geographical areas. These will be further investigated in order to fully evaluate the adaptive value of chromosome rearrangements.
The European ground squirrel (Spermophiluscitellus) is a vulnerable species (IUCN) living in open... more The European ground squirrel (Spermophiluscitellus) is a vulnerable species (IUCN) living in open habitats of Central and South-eastern Europe. Translocations (introductions, reintroductions and reinforcements) are commonly used as part of the European ground squirrel (EGS) conservation. There are numerous publications for such activities carried out in Central Europe, but data from South-eastern Europe, where translocations have also been implemented, are still scarce. The present study summarises the methodologies used in the translocations in Bulgaria and analyses the factors impacting their success. Eight translocations of more than 1730 individuals were performed in the period 2010 to 2018. These included 4 reinforcements, 3 reintroductions and 1 introduction. Two of the translocations are still ongoing. Five of the completed six (83%) translocations were successful, although in two cases the number of individuals was critically low. The relatively higher success in Bulgaria than in Central Europe is probably due to using the gained experience. Most of the translocations (6) used a soft release approach. In 6 cases, the animals settled 100 to 720 metres away from the release site, implying management and protection of suitable habitat beyond the translocation area. In 7 of the translocations, the altitude between the donor colony and the release site varied from 470 to 1320 m which could have a hindering effect on the adaptation of animals due to the specific conditions in the mountains. The main reasons for failure are probably poorly selected and maintained habitats and bad climatic conditions (rainy and cool weather) during the translocation action. European funds are of critical importance for translocations, with only two translocations funded by other sources. Based on the gathered data, the current paper also gives some recommendations for improvement in translocation activities.
The European ground squirrel is an endangered rodent whose populations are declining throughout i... 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 ...
The European ground squirrel is an endangered rodent whose populations are declining throughout i... 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 Bul-garian populations is preserved.
Bulgaria features a remarkable biodiversity owing to its geography and climate. At the same time ... more Bulgaria features a remarkable biodiversity owing to its geography and climate. At the same time it is much vulnerable to the introduction of alien plant and animal species. In the current paper we make a review of the information about alien species in Bulgaria (number of introduced species, pathways of introduction, status and impact of introduced populations), as well as policy, project, research and awareness raising activities related to alien species. So far the alien species within the reviewed taxonomic groups account for 340 vascular plant species, 347 terrestrial arthropods, 31 marine invertebrates, 3 freshwater bivalves, 23 freshwater fish, 1 reptile, 14 bird and 9 mammal species. About 12% of the alien vascular plant species, 25% of the aquatic species, 35% of the terrestrial arthropods, and 50% of the bird species were recorded after 2000. The main pathways of introduction of the alien species to Bulgaria and their further spread on the territory of the country include intentional as well as unintentional introductions. About 60 vascular plants, some terrestrial arthropods, most of the marine invertebrates and freshwater species, one reptile, two bird and four mammal species were reported as invasive and potentially invasive, with strong adverse impact on biodiversity, ecosystems, human health and economy of the country. Intensive project, research and awareness raising activities since 2000 focused on alien species inventory, study of their biological and ecological traits, an identification of the pathways of introduction, assessment of their impact and invasiveness, and development of risk management strategies. The results of this review demonstrate the urgent need of further studies and the development of a national strategy and risk management plan on invasive alien species in Bulgaria.
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Papers by Yordan Koshev
The article presents two of the three species of hamsters that inhabit Bulgaria - the Common Hamster (Cricetus cricetus) and the Dorbrudzhan/Black-breasted/Romanian Hamster (Mesocricetus newtoni).
Popular science review about the European ground squirrel/ souslik (Spermophilus citellus) in the journal "Lov i Ribolov". The article comments on the reduction of the european souslik population and the number of colonies in Bulgaria and the reasons for this.
The article presents two of the three species of hamsters that inhabit Bulgaria - the Common Hamster (Cricetus cricetus) and the Dorbrudzhan/Black-breasted/Romanian Hamster (Mesocricetus newtoni).
Popular science review about the European ground squirrel/ souslik (Spermophilus citellus) in the journal "Lov i Ribolov". The article comments on the reduction of the european souslik population and the number of colonies in Bulgaria and the reasons for this.