Predator–prey interactions may be linked to different temporal or spatial patterns, including dynamics in prey populations. Therefore, understanding the adaptive capacity and how top predators ...respond to shifts in prey abundance and availability is crucial for their conservation. In this study, we investigated the diet pattern of the endangered Eastern Imperial Eagle facing long-term and large-scale changes. We studied the abundance variation of its profitable prey, sousliks, and how it reflected on eagle population trajectories in a regional and temporal context. We found a significant diet alteration expressed in large decrease of brown hare (β2 = −0.83), poultry (β2 = −0.81), gulls (β2 = −0.71), and water birds (β2 = −0.57), and an obvious increase of northern white-breasted hedgehog (β2 = 0.61) and doves (β2 = 0.60). Raptors and owls raised their participation (β2 = 0.44), but white stork and different reptiles supplied more biomass. Abundance of European souslik decreased through the studied periods (adjusted R2 = 0.25, p < 0.001) which accounted for the lower proportion of this prey in the eagle’s diet. Nevertheless, the eagle population successfully adapted and significantly increased (β2 = 0.97) in most of the distribution area. The trophic strategy used by this top predator related to opportunistic foraging represents an ecological advantage that allows the species to adapt to different habitats and guarantees its future. The observed prolonged diet alteration could result in a significant negative attitude among different groups such as hunters, pigeon fanciers, and poultry keepers towards eagles. Therefore, enhanced communication with key stakeholders is needed. Conservation efforts should be focused also on the preservation of the species’ main foraging habitats and the restoration of damaged ones so as to maintain the good conditions of both primary food source and subsequent prey.
The Eastern Imperial Eagle (EIE) is a top predator exploiting different prey in different parts of its distribution. In this study, we summarise data collected over a long period of time (for 25 ...consecutive years), identifying key prey species in the different regions, as well as clarifying seasonal preferences in the eagle's diet. Most studies on the EIE food composition covering different parts of the species distribution range analyse the breeding season, while data about the winter diet are scarce. To the best of our knowledge, this is the first study detailing the differences in EIE's dietary preferences between the breeding and the winter periods. We identified 4891 specimens belonging to 196 different taxa, which represents the most comprehensive study considering the diet diversity of this threatened species. Mammals represented the largest proportion of the diet, followed by birds and reptiles. Northern White-breasted Hedgehog was the most common prey, accounting for 25.7% of the total prey caught and 26.75% of the biomass. The European Souslik was the second most important prey with 14.35% participation in the eagle's diet, but with a 3.75% contribution to the biomass. As we predicted, prey composition and main prey species varied spatially and seasonally. Modelling differences in the EIE diet, we found that the "territory effect" had the strongest impact on the dietary variations. Diet diversity differed significantly between regions (F = 12.6, df = 4, p = 0.01). During the breeding season, eagles fed mainly on Hedgehogs (29.88%), Sousliks (16.85%) and Storks (7.74%), while the winter diet was predominantly small rodents (44.17%) and songbirds (13.96%). We found that top predators, such as EIE, have successfully adapted to a novel food source, which is abundant in the area. The detected flexibility in the diet of the species and its ability to switch to alternative prey, if available, when the primary prey decreased, should be considered when planning species conservation efforts. Investigating the temporal change of the main prey in the eagle's diet is also crucial for further species conservation measures.
Myomimus roachi is one of the rarest and least studied mammals of the Western Palearctic. It is rare and sparsely distributed in the Southeastern Balkans and Western Anatolia. After its initial ...finding in 1959, the species was recorded only sporadically. All available data for the species distribution in Bulgaria are summarised and three new country records are reported, which all together increases the number of squares on the 10×10 km grid where the species has been recorded to 24. The current species habitats and threats are discussed.
Here we summarize all available data about dormice (Gliridae) in Bulgaria, published one and our own observations, collected in the last 20 years. Four species are found in Bulgaria - the Forest ...Dormouse (
Dryomys nitedula
), the Edible Dormouse (
Glis glis
), the Hazel Dormouse (
Muscardinus avellanarius
) and the Roach’s Mouse-tailed Dormouse (
Myomimus roachi
). Altogether we collected 1200 records from 283 locations. A database has been created in which every single record is kept. The most common and widespread species are the Edible (
G. glis
)
and Forest Dormouse (
D. nitedula
)
,
found in 212 and 139 locations respectively. They inhabit mainly the deciduous and mixed forest in the country. The Hazel Dormouse (
M. avellanarius
) is found in 77 locations, the bulk of them are in the mountains, but there are some locations along the Danube and southeast Bulgaria. It prefers woods with a well-developed understorey. The Roach’s mouse-tailed dormouse (
M. roachi
) is the rarest one - found in 26 locations in southeast Bulgaria. In contrast to the other dormice, it avoids woods and lives in semi-open habitats with shrubs, tree lines, and islands in grasslands and agricultural fields. There are several anecdotal reports of the Garden Dormouse (
Eliomys quercinus
) but no hard proof exists for the presence of this species. We discussed the patterns of distribution, conservation status, and coexistence of Bulgarian dormice.
The studied fossil material of birds and mammals from a new Late Pleistocene site in the Stara Planina (Balkan) mountain range is herein presented. The age of the site was determined on the basis of ...the taxonomic composition of the mammal fauna. A total of 28 taxa (10 birds, 15 small and 3 large mammals) have been identified from 103 bone/teeth specimens. Of these, 14.3% of the established species are extinct/disappeared – Perdix palaeoperdix, Megaloceros giganteus, Ursus ingressus and Cuon sp. Most numerous are the remains of Microtus arvalis-agrestis, representing 42.7% of all finds.
As a result of a large-scale study on the small terrestrial mammals (Eulipotyphla, Rodentia, Lagomorpha) of the Sarnena Sredna Gora Mts., through various methodological approaches and methods, we ...collected data about 2460 individuals, belonging to 30 species. The established species composition represents about 70% of the small terrestrial mammals of Bulgaria, which indicates the presence of a rich faunal complex. Of the established species, 6 are protected, 2 are defined as conservationally significant, with a limited distribution for the area, 3 species are synanthropic. For the first time we confirmed the presence of Sorex araneus, S. minutus, C. glareolus in the Sarnena Sredna Gora Mts. The nutria (Myocastor coypus), the European hare (Lepus europaeus), and the Red squirrel (Sciurus vulgaris) are hunting objects, and the nutria is also included in the list of invasive alien species in Europe. For the first time, the mountain habitats of the small mammal fauna of Sarnena Sredna Gora have been studied, typified, and mapped, and the species richness, zoogeographical structure, nature conservation status, and regularities in its distribution and origin have been analyzed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Srebarna lake, near the Danube River, Bulgaria, is a key site for biodiversity, specifically for ornithofauna. Thus, it has been designated as a managed nature reserve, a biosphere reserve, a ...Ramsar site, an Important Bird Area and Natura 2000 sites. Srebarna (and recently Persina Island) hosts the only breeding colonies of the Dalmatian pelican (
Pelecanus crispus
) in Bulgaria, assessed as critically endangered in the Bulgarian Red Data Book (2015). In April 2019, through a remote-controlled video surveillance system, we captured for the first time depredation of eggs of Dalmatian pelican by raccoon dogs (
Nyctereutes procyonoides
). As a result of regular Raccoon dog raids (up to three individuals simultaneously), about 25 nesting pelican pairs (approximately 30% of the Bulgarian breeding population) were disturbed and left the breeding grounds looking for new nesting places. These observations show that even few individuals of an invasive species such as the Raccoon dog can have a strong negative impact on concentrations of an endangered species; this necessitates taking proactive measures to control and even remove this species.
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.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Grey voles (subgenus
Microtus
), widespread in Eurasia, may be important pests and could cause serious damage to agricultural grain fields. In Bulgaria two morphologically similar species are present ...(
Microtus arvalis
Pallas, 1778 and
M
.
rossiaemeridionalis
Ognev 1924)
,
which are impossible to identify in the field. Despite their importance as pests, very little is known about their current status and distribution. Here we cotributed new data - based on karyological examination of 27 individuals of voles. We summarized all available information on the distribution of the voles – 20 published and 11 unpublished locations. Both species co-occurred together in north Bulgaria; in Thrace and the SE only
M
.
rossiaemeridionalis
is distributed
. Microtus
rossiaemeridionalis
seems to occupy lower elevations, while in the mountain areas (above 1000 m) only
M. arvalis
is found, which corresponds well with the data from neighboring countries. The taxonomy of both species in Bulgaria is discussed.
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