Lyubomir Kenderov

• PhD
• Professor (Associate) at Sofia University "St. Kliment Ohridski"

The assessment of the current state of lakes and reservoirs is a prerequisite for the conservation and management of these ecosystems as well as for their restoration and mitigation of the damages triggered by various pressures. The aim of the present study was to explore associations of the zooplankton communities with the trophic state and (or) e...

In the Black Sea area between the town of Sozopol and the island of St. Ivan, Bulgaria, dozens of petrified trees are exposed at a depth of 18–20 meters. This forest, probably existing in Miocene in a swampy pond, provides a unique setting to study later fossilization processes. Pyrite, a key mineral involved in the fossilization of organisms, cons...

Here we report the first fossil leaf imprint part of a leaflet of Gleditsia cf. lyelliana (Fabaceae). The studied leaf fragment was obtained from the sedimentary successions at the bottom of the Sozopol Bay hosted the Underwater Petrified Forest natural phenomenon. This is the first fossil record of Gleditsia cf. lyelliana collected from the territ...

Various processes trigger the formation, disappearance or expansion of lakes and ponds in Antarctica. Such dynamic ecosystems are a challenging environment for their inhabitants. We studied aquatic invertebrates in lakes and ponds on Livingston and Horseshoe Islands, Antarctica. Invertebrate fauna was either poor, in terms of diversity, or complete...

An amplicon-based metagenomic survey of archaea, fungi, and bacteria was performed on Livingston Island, Maritime Antarctica. In many of the samples, patterns of antagonism between these three superkingdoms were observed in the form of an inversely proportional dependence of the richnesses of the three types of microorganisms. The antagonism was qu...

The current study is part of a comprehensive investigation of the natural phenomenon Underwater Petrified Forest, which has no analog in the Black Sea and is very rare worldwide. The team aims to conduct a comprehensive study of the unique habitat, paleontological and geological phenomenon, the Petrified Forest, and to address a series of scientifi...

Within an amplicon-based metagenomic study of Archaea, Fungi, and Bacteria in Livingston Island, Maritime Antarctica, in many of the samples antagonisms between these three super kingdoms were observed under the form of an inversely proportional dependence of the richnesses of the three types of microorganisms. This was quantified - based on the ob...

The available data on the localities (including new localities) of the calanoid copepod Boeckella poppei on the Livingston Island, Maritime Antarctic, are summarised. The results suggest a substantial expansion in the distribution of the species, likely owing to recent climate change and the resulting freeing from permanent ice or snow of additiona...

South Shetlands are exposed to some of the most intensive climate changes on Earth. Ice and snow retreat trigger expansion of distribution ranges of Antarctic mosses and higher plants. We collected specimens of Antarctic hair grass (Ahg, Poaceae), Antarctic pearlwort (Ap, Caryophyllaceae) and Antarctic mosses (Am, Bryophyta) and used untargeted gas...

Antarctic environments are exposed to high levels of ultraviolet radiation (UVR) that are often detrimental to their biota. Recent studies suggest that the genus Boeckella (Copepoda, Calanoida) has a high level of plasticity in terms of its reaction to UVR, which enables its wide distribution in various water bodies in Antarctica. Boeckella poppei...

The upper Iskar sub-catchment is one of Bulgaria’s most important economic and socially significant water sources because of its role in supplying Sofia with drinking water. Among the critical factors that carry potential high-risk levels for water quality in this hydrosystem are the discharge from the Samokov Wastewater Treatment Plant (WWTP), dif...

All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. Sturgeons are mainly benthic feeders, with a diet of molluscs, crustaceans, and small fishes. During the last two decades, we have seen a significant change in the species composition of benthic invertebrates in the Danube River...

Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air...

The River Danube has played a pivotal role in the range expansion of Ponto-Caspian faunal elements in recent decades; therefore, the monitoring of its biota is of high scientific and conservation importance. In this publication, the records on peracarid crustaceans yielded by the macrozoobenthos samples for the 4 th Joint Danube Survey (2019) are p...

Expansion in the distribution of B. poppei on the Livingston Island, Maritime Antarctica.

Accumulation of carotenoid pigments in oval sacs of ovigerous females.

https://acta-zoologica-bulgarica.eu/2021/002394.pdf The survey on the fish fauna of the coastal area of South Bay, Livingston Island, was conducted in No-vember 2018-January 2019. Fish were caught by bottom trawl net and fishing rod. Five fish species have been identified: Notothenia coriiceps Richardson, 1844, N. rossii Richardson, 1844, Trematom...

Aim Although running waters are getting recognized as important methane sources, large‐scale geographical patterns of microorganisms controlling the net methane balance of streams are still unknown. Here we aim at describing community compositions of methanogenic and methanotrophic microorganisms at large spatial scales and at linking their abundan...

The Iskar River, a Danube tributary, is the longest Bulgarian inland river, flowing through seven geographical areas of Bulgaria. It crosses one of the most urbanised and densely populated areas in Bulgaria—the city of Sofia and its surroundings; and it plays a major role in water supply for drinking, household and industry, discharge of sewage, ir...

Elodea nuttallii (Hydrocharitaceae) is an aquatic plant, native to North America. In Bulgaria, the species was recorded as a naturalised alien relatively recently – in 2002. Since then, the number of the recorded localities has increased rapidly. In Europe, the species has been considered to have high ecological impact in the invaded areas, and the...

The national legislation on surface waters characterization (Regulation N4/2012) was applied for the lotic ecosystems in Torfeno Branishte (Vladayska and Boyanska Rivers) and Bistrishko Branishte Reserves (Bistritsa and Yanchovska Rivers) in view of ecological status assessment. Water samples were collected and analysed both for physicochemical ele...

Background: Globally, streams emit significant amounts of methane, a highly potent greenhouse gas. However, little is known about the stream sediment microbial communities that control the net methane balance in these systems, and in particular about their distribution and composition at large spatial scales. This study investigated the diversity a...

Microinvasive methods are widely used in studies of rare and endangered animals. All sturgeon species currently living in the Danube River are either critically endangered or at the edge of extinction. The reasons for this are complex, but one of the possible is changes in food resources. Although sturgeons have been studied on a systematic and zoo...

Antarctic marine organisms are characterised by a significant level of endemism. This is due to geological, climatological and oceanographic reasons, such as the break-up of Antarctida from Gondwana during the Cretaceous; the formation of a circumpolar current; the extremely low water temperatures (close to freezing); the short summer seasons. The...

Hydrobiological monitoring and assessment of ecological status (potential) of eight Bulgarian reservoirs wеre carried out in 2015-2016. The water bodies are located in Ecoregion 7: West (Pchelina Reservoir) and East Aegean River Basins (Chetiridesette Izvora, Konush and Sinyata Reka Reservoirs) and Ecoregion 12: Danube River Basin (Bebresh, Telish,...

Zooplankton communities have several vital functions within lake ecosystems, including the transfer of energy and material from producers to secondary consumers. Their structure is potentially affected by both lake morphology and typology, as well as by anthropogenic changes in lakes. These communities are also sensitive to various substances in th...

Aphelocheirus aestivalis is a stenobiotic species with low dispersion ability. It is the only member of the family Aphelocheiridae found in most of Europe. Hydromorphological changes and water pollution threaten its subpopulations. Considering the vulnerability of the species, more accurate data about its occurrence and geographic distribution are...

National Park "Central Balkan" is the second largest national park in Bulgaria with a total area of 717 km 2. There are nine Nature Reserves on its territory. Several large tributaries of the Danube watershed (Vit, Osаm, Rositsa and Yantra Rivers) and Aegean watershed (Tundzha River) have their sources in the Park. The main length / parts of these...

The paper presents data on the total biodiversity, the newly described and threatened, rare and invasive species of the complex wetland Atanasovsko ezero, which is situated in the vicinity of the town Burgas on the southern Black Sea coast of Bulgaria. Different parts of Atanasovsko Ezero were declared as Managed Reserve, Ramsar Site, Protected Zon...

Single specimens of invasive mussel species Dreissena polymorpha (Pallas, 1771) were found in the middle part of the Iskar River, Bulgaria during 2016 and 2017. A cascade of 14 small HPPs was built in this river sector and a shift in the flowing river conditions with stagnant ones in SHPP dam lakes was induced. Future mass invasion of the species i...

Tsibar Island is situated in the Bulgarian part of the Danube River, at 680 m of the Bulgarian and about 100 of the Romanian coast from 716 to 719 km along the river, with an area of 1.3 km². The territory is covered mainly by riparian woodland. Because of its European importance to the protection of rare and threatened habitats, plants and animals...

The round goby Neogobius melanostomus (Pallas, 1814) is a fish species native to the Ponto-Caspian region and invasive for most of European rivers, performing rapid expansions upstream of the Danube River. The aim of the current study was to investigate the distribution of the species in Bulgarian tributaries of the Danube River. A total of 12 rive...

A zebra mussel specimen (Dreissena polymorpha) was recorded attached to the chitin cover of a killer shrimp (Dikerogammarus villosus). This is a rarely observed interspecies relationship (phoresis) between two of the top invasive aquatic macroinvertebrates in Europe. Thus, the zebra mussel obtains some opportunity for passive migration and probably...

Recent information about the ecological status of upper part of Iskar River and some tributaries was given. Ecological assessment according WFD and national water legalisation (Regulation N4) was applied. For estimation of fish based indices (BRI and TRI) the following ichthyologic parameters were used: total abundance and biomass of ichthyofauna,...

Fecal pollution from municipal wastewater discharges is an extremely serious problem for aquatic ecosystems. This type of pollution is also found in the waters and sediments of the Iskar River in its upper and middle valley. From a microbiological point of view, an indicator of such contamination is the presence of high amounts of opportunistic pat...

The first find of a freshwater tardigrade in Bulgaria was reported: unidentified Dactylobiotus specimen from the hyporeal waters of Cherni Iskar River.

The Water Framework Directive (WFD) aims to achieve good ecological status (potential for heavily modified water bodies) of surface waters. Ecological status is characterised by the quality, structure and functioning of aquatic ecosystems. It is quantified through chemical and ecological parameters, with standard biological quality elements (BQE) f...

We present the first confirmed finding of the larval stage of Calamoceras illiesi Malicky and Kumanski, 1974 (Trichoptera) from Europe where, so far, the species was known only as adults and pupae. We collected larvae from three localities in Strandzha Mountain, southeastern Bulgaria. The main morphological characteristics of the larvae from the Bu...

The medicinal leeches of the genus Hirudo are among the invertebrates with the best studied biology and physiology, because of their wide application in medicine. However, till the end of the 20th century, there was confusion regarding the taxonomic status of the different morphological forms of these leeches. The prevailing view was that all varie...

Species diversity and distribution of benthic macroinvertebrates in 51 of the largest Bulgarian natural lakes and reservoirs were studied in 2011 and (or) 2012. This work presents the first comprehensive faunistic composition of Bulgarian standing water bodies. The up-to-date check-list includes 297 taxa belonging to 22 systematic groups. These inc...

This work summarizes both literature and new data on the fauna of Plecoptera (Insecta) of the Vrachanska Planina Mountains, Bulgaria. A total of 20 species and seven subspecies are known from the mountain. The recorded stoneflies belong to 12 genera and seven families. They represent 25% of the 108 stoneflies currently known from Bulgaria. Among th...

Assessment of the ecological status of river ecosystems of the major watersheds in the Vrachanska Planina Mts. (Leva River, Cherna River and some tributaries) is made. The assessment is carried out by determining the composition and structure of phytobenthos, benthic macroinvertebrate communities and fish. The following indexes are calculated: diat...

Faunistic data on the larval stages of the insect order Trichoptera from the Vrachanska Planina Mts. are presented for the first time. A total of six locations in four rivers were sampled. Twenty-one taxa belonging to seven families were recorded. They represent a little more than 8% of the Trichoptera species, found on the territory of Bulgaria. T...

The role of the Atanasovsko Lake for storage and protection of the specific faunistic diversity, characteristic of the hyper-saline lakes of the Bulgarian seaside is presented. The fauna of the lake and surrounding waters is reviewed, the taxonomic diversity and some zoogeographical and ecological features of the invertebrates are analyzed. The lak...

A new species of the order Amphipoda and the family Niphargidae is described. Niphargus cvetkovi sp. n. was found in groundwaters from Bulgaria. The new species can be attributed to the aquilex-tauri species group and undoubtedly to the tauri sub-group. It resembles some species of this group, such as N. tauri Shellenberg, 1933; N. jurinaci S. Kara...

Water column transparency, dissolved oxygen concentration and saturation as well as pH values were measured and analysed in 52 freshwater bodies (lakes and reservoirs) with or without Dreissena spp. Water column transparency measured by Secchi disk indicated statistically higher transparency, while dissolved oxygen concentration was significantly l...

The stone crayfish Austropotamobius torrentium is one of the three native crayfish species occuring in Bulgaria (the other two are Astacus astacus and Astacus leptodactylus), which is protected by many European and national laws. In comparison with other European countries little is known about the population status of stone crayfish in Bulgaria. T...

The reservoirs Ogosta, Zhrebchevo and Koprinka were studied in the period 2009-2011. The Secchi Disk transparency and amount of chlorophyll-a were used for the assessment of the trophic state in the reservoirs. The structure and functioning of the trophic web and trophic integrity were analysed based on the composition of phytoplankton, benthic mac...

An environmental assessment of 16 sampling sites in the Iskar River catchment has been fulfilled urn accomplished for the period April 2004 - August 2006. The following basic structural parameters of macrozoobenthic communities have been determined: dominance (c), evenness (e), species diversity (H), species richness (d) and the saprobic index afte...

Three native crayfish species occur in Bulgaria: Astacus astacus, Astacus leptodactylus and Austropotamobius torrentium. Data on their distributions were published in 1961 and 1998. Our goal is to summarize newly collected data on crayfish distributions and population status, as a basis for subsequent river basin and conservation management. Sample...

Environmental management requires the solution of problems through a comprehensive and thorough examination of all levels – from biochemical analysis to bio managerial approaches. The chemical and microbiological parameters of water in depth in micro-dams Lakatnik and Svrazhen have been investigated in June and September, 2011. Linear correlations...

Twelve reservoirs in North-West Bulgaria were sampled in autumn 2009 to study the species diversity and distribution of benthic macroinvertebrates in relation to some environmental parameters, and to assess the ecological potential of the reservoirs based on macroinvertebrate metrics. A total of 75 taxa belonging mostly to Oligochaeta, Ephemeropter...

The first record of the Asian clam Corbicula fluminea in Bulgaria was from the Danube River at Vetren in 2001. In 11 years the species has established in the entire Bulgarian stretch of the Danube, from Vrav (rkm 836) to Vetren (rkm 395), where it reached densities up to 16 560 ind./m2. The species extended its range rapidly upstream of the Danube...

A key factor for realization of the self-purification potential in the hydroecosystems is the functioning of microbial communities. Their flexible metabolism is in the base of the biotransformation processes of the organics and nutrients. The functional diversity can play the role of an indicative mechanism and its adequate elucidation presents an...

14 species of free-living nematodes and 22 species (larval stage) of family Chironomidae (Diptera) from the riverine and hyporheic habitats of Iskar River catchment are reported in this study. The five chironomid species and two nemic species were new for the faunal list of this catchment. The most of the identified chironomid species were found in...

Andreev S., Kenderov K. 2012. Sur une nouvelle espèce du genre Niphargus de la Turquie – Niphargus turcicus n.sp. (Amphipoda, Niphargidae). – Historia naturalis bulgarica, 20: 47-56. Abstract. A new species of Amphipoda, Niphargidae – Niphargus turcicus n.sp. is described in the present study. Found in two caves in the Northern part of Central Turk...

Rilska River is one of the left tributaries of Struma River and it is a substantial source of drinking water for the capital city of Sofia. In spite of that the hydrobiological data are quite poor, especially these concerning bottom invertebrate fauna. This study presents the results from research on the macrozoobenthos species composition carried...

Five sites from the upper part of the Iskar River watershed (from the inflow of the Beli Iskar and Cherni Iskar rivers to Iskar Dam) were investigated during the 4 seasons of 2004. Totally 166 taxons (94 at species and 44 at generic taxonomic level) from 18 basic benthic invertebrate groups were found as a result of the study. The species Hydropsyc...

This paper is one part of the complex studies and intends to provide the background for explaining the spatial differentiation of macroinvertebrate and microbial community settled in the Iskar River. The study has been conducted along the whole river course. Total amount of Cu, Zn, Pb, Mn and Fe in three key sub-ecosystems (surface water, hyporheic...

The following paper is a part of the complex study and intends to provide the background for explaining spatial values characteristics of chemical parameters and microbial communities in the Iskar River. The study has been conducted in the medial part of the river. Relationships among stream surface water, substream hyporheic water and sediments we...

Построяването на хидротехнически съоръжения налага предпроектни екологични проучвания, свързани с активните форми на ОВОС, изследвания по време на степенното разгръщане на строителството и изпълнение на целева мониторингова програма при реалната експлоатация. Направено е предпроектно проучване в критичните точки на замърсяване на повърхностната вод...

SYNOPSIS This work investigated the crustacean hyporheic complex of the Iskar River and its tributaries Beli Iskar, Cherni Iskar, Vedena River. During the study 43 different (sub)species taxa of crustaceans were found. Twenty-one (sub) species taxa were reported for the first time in the Iskar catchment. The orders Harpacticoida and Cyclopoida show...