Field of Study – Ecology and Environmental sciences (N 012)

Chemical pollution is one of the global anthropogenic factors accelerating the decline of biodiversity. Current methods for environmental monitoring and assessment primarily focus on chemical and ecological measurements, with limited exploration of their interaction, specifically the biological impact. The assessment of chemical status does not ensure compliance with the description provided in Descriptor 8 of the Marine Strategy Framework Directive (MSFD), which outlines the essential requirements for achieving good environmental status of marine ecosystems. Existing EU regulations, such as the MSFD and the Habitats Directive, are already undergoing review, emphasizing the need for integrated chemical and biological monitoring and assessment systems. In order to uncover the potential of integrating chemical-biological monitoring, this dissertation research will investigate the impact of chemical pollution on aquatic ecosystems, particularly on species health. Studies will be conducted using Atlantic salmon and sea trout as model species to evaluate their suitability for chemical-biological monitoring, assuming that these migratory fish exhibit a high potential to reflect cumulative and synergistic environmental pollution effects. The investigation of fish will encompass cytogenetic, biochemical, hematological, population parameter, and biological biomarker analyses to assess their health during the spawning migration period. To identify individuals and monitor changes in the studied biomarkers over time, captured individuals will be tagged with internal radio-frequency identification (RFID) markers. The study aims to detect early genetic biomarker signals of environmental pollution effects, conduct comparative analyses of these biomarker responses in fish from various rivers in Lithuania, and establish baseline levels of cytogenetic biomarkers in salmonid fish species. These investigations have the potential to promote the integration of biological effect assessment into the monitoring programs of aquatic ecosystems, thereby enhancing our comprehension of the cause-and-effect relationships between environmental pollution, biodiversity alterations, and ecological conditions. The research findings can serve as a foundation for the implementation of novel criteria, the formulation of practical recommendations for biological effects assessment, and the advancement of methodologies for evaluating the status of aquatic ecosystems.

Fungal diseases, such as saprolegniasis, are common in the aquaculture sector and natural environment, but effective methods to prevent disease outbreaks have yet to be developed. The entry of chemical substances into the environment leads to increasing environmental pollution, which promotes the adaptation of pathogenic organisms to environmental changes. Currently, little is known about the impact of environmental pollutants on the (patho)biology of stramenopilous fungi. Considering that many species of stramenopilous fungi are causative agents of destructive diseases and environmental pollution can influence their pathogenicity (hormesis, pollution-induced synthesis of mycotoxins), knowledge about changes in pathogenicity in the context of environmental pollution (“something from nothing” phenomenon) becomes of great importance.

The dissertation will cover the identification of stramenopilous fungi in fish farms and natural water bodies, the assessment of pathogenicity of isolated species to salmonid fish, changes in pathogenicity in the context of environmental pollution, and research on the induced biological effects. To obtain a comprehensive assessment of the biological effects caused by (a)biotic factors, studies will be carried out using cytogenetic, physiological, and biochemical biomarkers. Stramenopilous fungi will be isolated from water samples, and the isolates will be cultured and identified to the species level using morphological and molecular methods (analysis of the rDNA ITS gene region). The research aims to acquire novel scientific insights into the interactions among pathogenic stramenopilous fungi, fish, and pollution within aquatic ecosystems. It seeks to examine the ecotoxicological consequences for fish, assess the fundamental mechanisms contributing to saprolegniasis outbreaks in relation to (a)biotic factors, and evaluate the susceptibility of both artificially bred and wild salmonid fish to (a)biotic factors and their synergistic impacts. The investigation will identify and compare the species diversity of stramenopilous fungi between salmonid fish farms and salmonid rivers. The findings will provide valuable insights for refining existing guidelines on assessing the environmental impact and risk posed by multiple stressors. Furthermore, they can aid in enhancing monitoring programs for water pollution effects on ecosystems by integrating biomarkers of biological effects and formulating or enhancing measures to mitigate the adverse environmental consequences of aquaculture.

In ecosystems birds of prey are at the top levels of the food webs, therefore are sensitive to anthropogenic induced environmental changes. Birds of prey because of their long-life span and faithfulness to the nesting sites are suitable as model organisms to study responses to environmental changes, population dynamics and different ecological mechanisms. Despite long lasting research of birds of prey ecology, still are insufficient knowledge on ecology, behaviour and their changes during maturation of young individuals before adulthood. Large birds of prey usually don’t start breed before they achieve reproductive maturity after four to five year of the age. Immature birds of prey often die because of natural and anthropogenic reasons as they are not experienced to find the food, to avoid dangerous anthropogenic activity or elements. Individuals are also inexperienced in dispersal, migration and wintering behaviour, finding suitable stopovers to rests and feed, crossing geographical barriers. Therefore, understanding immature individuals behaviour during different phases of annual cycles and changes of behaviour during maturation is crucial to understand demography, population trends and conservation of rare and endangered species.

The key aims of this PhD topic are related to the behaviour such as migration, dispersal patterns, survival and factors influencing it, space and habitat use, and these changes during maturation before attaining adulthood in birds of prey (Accipitriformes). For the analyses will be used data collected by two complementary methods, i.e., telemetry and colour ringing.

Anthropogenic activities induced global and local changes drives ecosystems. Individuals of resident species, which spends the complete annual cycle in the same ecosystem, are affected by the different driving factors simultaneously. Phenotypic plasticity is a mechanism providing opportunity for the species to cope with environmental changes. Therefore, research of resident organism allows to study responses and adaptation mechanism to rapid changes in environments inhabited by the species.

Tawny Owl (Strigiformes, Strix aluco) – is a resident and territorial species for which characteristic colour polymorphism. This species is a suitable to study phenotypic plasticity because of life-history traits. Despite that different aspects of Tawny Owl ecology and demography were widely covered, however, previous studies were mainly focused on different patterns or responses during the breeding season, which covers only part of annual cycle. Research outside breeding season were mainly restricted by the lack of suitable methods resulting in limited understanding even of mechanisms of phenotypic plasticity described previously.

The aims of this PhD topic are mainly related to development of conventional and telemetry methods suitable for research of Tawny Owl during autumn and winter seasons, various aspects of ecology outside the breeding season, pair formation and break-up, phenotypic diversity and spatial distribution, spatial and temporal phenotypic changes, and consequences to population demography.

Host – parasite interactions: factors shaping communities of mammalian parasites.

The aim of the study is to investigate parasite diversity of mammals and to determine factors shaping parasite communities.
During the study, parasite diversity of various mammalian species will be investigated with special attention to zoonotic diseases. Influence of various factors on parasite communities will be analysed. Obtained results will expand understanding on the ecology of host – parasite interactions and provide information for control and prevention of zoonotic disease.

The fate and behavior of nano-sized materials in aquatic ecosystems, as well as their interactions with other organic and inorganic pollutants, remain largely unexplored, presenting a real challenge. Data regarding the combined effects of nanoparticles (NPs) and various pollutants on aquatic organisms, food chains, and ecosystem sustainability are notably scarce. NPs exhibit unique physicochemical properties that render them useful in fields such as biomedicine, industry, and environmental protection. Within the European Union, efforts to tighten controls on hazardous pollutants and increased environmental requirements for preserving a sustainable environment and human health continuously stimulate the search for innovative wastewater treatment technologies. Certain NPs have robust sorption capacities, making them viable candidates for removing pollutants from aquatic environments. However, once introduced to the environment, NPs may accumulate in aquatic ecosystem, potentially leading to unpredictable changes in the functional status of organisms. A full comprehension of the impact mechanisms of NPs interactions with other pollutants requires additional research to elucidate how the physicochemical properties of NPs are related to their effects on living organisms. In this investigation, we aim to explore the effects of carbon-, metal-, and polymer-based NPs, as well as their mixtures with metals and pharmaceuticals, on fish and crustaceans. Our methodology will not only employ conventional ecotoxicological techniques but also take advantage of an innovative system breeding and rearing (Tecniplast), evaluating morphophysiological parameters (Danioscope and Daniovision), and utilizing analysis systems (Embryonet, MetaboAnalyst) for Danios rerio and other small aquatic organism. This study aims to examine, for the first time, the complex influence of NPs and various pollutants on aquatic organisms during their early, stress-sensitive developmental stages (i.e., embryos, larvae, fry). We will determine the interactions of NPs with various pollutants and evaluate their effects based on NP size, shell type, and structure. The acquired results will be instrumental in elucidating the mechanisms of metal- and carbon-based NPs’ effects on aquatic organisms. It will also broaden the application possibilities of NPs in environmental protection and biomedicine.

The EU, as well as other countries in the world, is starting to restrict or ban chemical insecticides. This creates a strong need to find alternatives for controlling economically important insect pests. Entomopathogenic nematodes (EPNs) are already widely applied as an environmentally friendly biological control method for agricultural pests around the world. Despite the applicability of EPNs, a number of questions arise regarding their biology, distribution, diversity, and ecology, which are important for the effectiveness of their application. In Lithuania, biodiversity of EPNs is unknown, thus the basis for studies on interactions with other organisms has not been established.

The species composition and diversity of EPNs and their symbiont bacteria in Lithuanian soils will be studied. It is expected to isolate and identify new bioactive chemical compounds affecting EPN behavior, which may serve as targets for the selection of crop varieties with higher resistance to pests due to the exploitation of natural potential.

From a scientific and environmental point of view, understanding how environmental factors and impacts, including anthropogenic ones, can affect the hydrology of rivers, their water quality and related to river basin ecosystems is essential. At the moment, there is an increased interest of possible emissions from the Belarusian nuclear power plant (NPP) and the response of the environment to them. Whereas the probability of sudden incidents of a large impact on the environment at nuclear power plants are minor, but when they occur lead to different level consequences due to sudden and strong destructive properties. One of the purpose of this work would be to create a predictive model of the Neris River assessing the impact of possible events leading to environment pollution. With the consequences of such events, we must learn to live, at least reasonably from a scientific point of view. Also, based on isotopic studies of the water system, to develop a dynamic model for tracking pollution sources, which could characterize the relationship between the water system and the source of risk, is of primary importance.
River systems are very complex, so modeling is one of the important tools that can show the impact of different events under different conditions. The developed risk assessment model would be an effective tool for systematically quantify random uncertainty due to processes in the river system, as well as providing information when making decisions on the control of sudden water pollution, identifying critical sources and quantities of pollution. For the implementation of the work, isotopic research methods and a modern modeling program would be used.
The importance of the transfer of tritium in aquatic ecosystems was highlighted in studies performed in Canada and France (CNSC 2010; ASN 2010). Calibration of the transport model according to tritium data in rivers and modeling of the groundwater age was carried out in the western basin of Lake Taupo, New Zealand (Gusyev et al. 2013). To better understanding the transport process simulation of HTO from surface water to the atmosphere was carried out (Marang et al. 2011). Modeling of groundwater discharges into the river based on radon mass balance using tritium data was performed on the Elbe River, Germany (Schubert et. al 2020). The characterization of water systems is therefore an important for both issues such as construction of new nuclear power plants and the decommissioning of old ones. Transport models realize a mathematical description of the movement of radionuclides in a particular component of the environment (air, surface water, groundwater, biota) the purpose of which is to predict the concentration of radionuclides. In Lithuania, investigations of water systems using modelling tools were carried out mostly in relation to groundwater. Number of studies have focused on the formation of groundwater in the Baltic Artesian Basin (Vaikmäe et al., 2001; Cheban, 1966; Mokrik and Vaikmäe, 1988, Mokrtik et al. 2014; Mokrik and Samalavičius, 2021). The research interests include various aspects of palaeohydrogeology, origin issues and formation scenarios. Isotopic studies of the hydrological cycle including precipitation, streams and lakes, groundwater and other water bodies were performed since the beginning of operation of the Ignalina Nuclear Power (Jakimavičiūtė-Maselienė et al. 2012; Vaitkevičienė et al. 2013; Mazeika et al. 2013; Jefanova et al. 2018).
Because of the tritium mobility in hydrological cycle and well-known atmospheric abundance it is of great importance in line with other mobile radionuclides to carry out tritium measurements in the water bodies surrounding nuclear facilities and use data fot the environmental quality and risk assessment.

Due to their functional and magnetic characteristics, graphene and iron-based nanocomposites have attracted remarkable scientific and economic interest in biotechnology and nanomedicine. In recent years, there has been a significant focus on the practical application of functionalized magnetic adsorbents in water purification processes, particularly when combined with magnetic separation technologies. Considering that the production and use of nanomaterials will only increase in the future and that legal regulation of these materials in the manufacturing and waste management sectors has yet to be implemented, research on the impact of these nanoparticles on aquatic organisms in the context of a changing environment becomes important.

Magnetic nanoparticles possess a magnetic moment, enabling them to generate a magnetic field or respond to one. The primary sources of (electro)magnetic fields are wind turbines and their accompanying infrastructure. The development of renewable energy resources is gaining momentum worldwide, including in Lithuania. A 700 MW wind turbine power station is expected to be operational in Lithuanian territorial waters in the Baltic Sea by 2028. However, there is currently a lack of scientific evidence regarding the effects of (electro)magnetic fields on species in marine ecosystems.

The examination of these materials’ shape and functional properties will include parts of the synthesis, modification, and characterization of specific graphene and iron nanoparticles, as well as their nanocomposites. The hazardous effects of these nanomaterials on fish and invertebrates will be examined at several levels of biological organization to find patterns of nanoparticle impacts on organismal functional systems, biochemical and behavioral response patterns, and probable toxicity pathways. Comparative studies will be conducted on the anthropogenic effect of (electro)magnetic fields on aquatic organisms, employing sophisticated indicators of biological response and biomarkers. The regularities of nanoparticle toxicity will be investigated in the relationship between (electro)magnetic fields and chemical stress to better represent the effect of the multifunctional environment on the biological accessibility and toxicity of nanoparticles. The findings may be used to forecast potentially harmful quantities of these nanomaterials in the environment, as well as their interactions with physical stressors, which might generate complicated biological impacts in the context of a changing environment.

Laboulbenialean fungi (Laboulbeniales, Ascomycota, Fungi) are microscopic superficial parasites of arthropods. The Laboulbeniales are a group of insect-associated fungi with a relatively strong specialisation, with 145 genera and about 3000 species described (Thaxter, 1926; 1931, Tavares, 1985, et al.), but current estimates suggest that there are at least 40,000 species awaiting description (Haelewaters et al., 2020; Kirk, 2019; Weir & Hammond, 1997). The effects of Laboulbeniales fungi on their insect hosts are not fully understood and there is still very little research on their ecology and biology (Haelewaters et al., 2021). Only a small number of countries have ongoing research on Laboulbeniales, but the diversity and uniqueness of this group of fungi undoubtedly makes it a source of new taxonomic and ecological information. The taxonomic characters of Laboulbeniales are based on the structure of the fruiting body, i.e. the visible part of the fungus outside the host. The attachment of the fungus through haustoria and its spread within the host remains largely unknown, but it has been established that some Laboulbeniales species have a haustorial structure that penetrates the cuticle of the host, while others  only attach  to the cuticle of the host, but do not penetrate it, and it is not clear what nutrients they use for their own growth ( Reboleira et al., 2021). The first major comprehensive taxonomical work on Laboulbeniales, which resulted in a 6-volume monograph, was carried out in the Americas by Roland Thaxter (Thaxter, 1926-1932). Among European countries, more detailed studies on Laboulbeniales have been carried out in Italy (Rossi, 1978; 1979), Spain (Santamaria, 2020; 2001) and Poland (Majewski, 1994; 2008). The first studies in neighbouring Latvia (Briedis, 1932) and in Lithuania were carried out almost 100 years ago (Siemaszko and Siemaszko, 1928; 1932). During the last decade, the Belgian entomologist De Kesel (2006) found, described and published several new species in Latvia. This ecologically interesting group of fungi has hardly been studied in Lithuania, and there is very little data on the diversity, distribution and ecology of Laboulbenialean fungi – only two papers have been published (Markovskaja, 2000; 2006). Biodiversity research will undoubtedly have to include taxonomic studies, as there is a high probability of discovering new species. Scientists currently studying Laboulbeniales in Belgium, Spain and Italy are more involved in diversity, ecology and taxonomy research and are in close contact with each other, organising joint expeditions and hosting interns. This international collaboration has resulted in several papers on Laboulbeniales from Bulgaria, Hungary, Czech Republic, Slovakia and other countries (Pfliegler et al., 2016; Rossi et al., 2019; Rossi & Santamaria, 2020).

The research to be carried out in the dissertation

Field surveys: collection of material (arthropod insects) in different regions and habitats of Lithuania. Laboratory studies: selection of infected insects using a stereomicroscope, removal of fungi from the insect and production of permanent preparations, identification of insects and fungi using light microscopy.

Inspection of existing entomological collections at the VU, GTC, and Tadas Ivanauskas Zoological Museum in Kaunas, as well as of amber collections with insect inclusions, to look for infected insect specimens with Laboulbeniales fungi. Close cooperation and consultations with entomologists in Lithuania and abroad. Internship abroad with one of the best Laboulbenialean fungi specialists ( W. Rossi / S. Santamaria or other).

Most fungi in this group are highly specialised and through a long coevolutionary process adapt to parasitise a particular insect species or genus. Correct identification of Laboulbeniales depends primarily on correct host identification. The identification of insects will require entomological knowledge, which will need to be developed.

Taxonomic and ecological analysis of the collected material, determination of the distribution and host specificity of the insects, clarification of the trophic relationship between host and parasite. Use of molecular methods for the identification of new species and morphologically similar species, phylogenetic analysis. Preparation and publication of taxonomic and ecological papers. Preparation of an illustrated synopsis with species descriptions.

The conservation issues of crop wild relatives (CWR) and wild harvested plants (WHP) are particularly relevant with the intensification of climate change. Research on the effects of climate and environment changes on economic plants already constitutes a distinct block of research that is closely related to the conservation of plant genetic resources. Currently, research is needed to predict the functioning of CWR and WHP populations and the possibilities of their conservation to ensure their sustainable use for human needs.

The aim of research on the development of conservation strategies for crop wild relatives and wild harvested plants is to assess the diversity, distribution, condition, and trends of these biological resources under the pressure of climate change and, considering the actual and potential threats, develop reasonable measures to ensure their conservation in situ.

The research tasks: carry out a national inventory of crop wild relatives and wild harvested plants; identify priority plant species based on approved criteria; carry out studies of the distribution and genetic diversity of priority species through ecogeographical analysis, genetic studies of model species, herbarium data, GIS and other tools; assess the role of ex situ conservation; identify threats to the conservation of target plant species and conservation gaps; prepare recommendations for practical application.

The research may include: (1) diversity assessment of crop wild relatives in relation to the diversity of cultivated plants and their socioeconomic importance to the country, preparation of criteria for the identification of priority taxa, compilation of a list of priority taxa and distribution analysis, determining hotspots of their diversity, assessment of genetic diversity of selected species, identification of condition and gaps in genetic resources conservation; (2) studies of the diversity of populations of wild harvested plants, e.g., medicinal plants, by identifying and using morphometric markers, conducting research on bioactive substances (e.g., essential oils, to identify chemotypic diversity), assessing the popularity of medicinal plants use among local communities by means of surveys, determining the trends of changes in target plant resources.

Soil is one of the most valuable natural resources, consisting of mineral particles, organic substances, water, air and living organisms. Every year, more and more functions of soil are being elucidated, and soil plays an active role in maintaining the quality of groundwater, surface water, and the atmosphere. Especially many microscopic fungi are found in forest soil. Forest soil is a major reservoir of microorganisms with a significant influence on organic carbon accumulation, soil structure, fertility, productivity, and plant growth. The main function of microscopic fungi in the soil is the active decomposition of organic matter. Fungi are able to synthesize and release into the environment a lot of hydrolytic enzymes that break down any organic matter, besides releasing organic acids, they dissolve phosphates that are difficult for plants to access, thus improving plant nutrition. The microscopic fungi of the upper mineral soil layer of the forests of Eastern and Southeastern Lithuania, their diversity, biological properties, and destructive properties will be studied. Microscopic fungi from the soil will be isolated by classical microbiological methods, and identified by phenotypic and molecular methods, their abundance and distribution will be determined, and their various enzymatic properties will be studied. The aim will be to obtain new knowledge about the intraspecific and interspecific diversity of microscopic fungi in the upper layer of the soils of Eastern and Southeastern Lithuania. New and valuable species/strains of microscopic fungi will be added to the Microorganisms Collection of the Laboratory of Biodeterioration Research.

The Ponto-Caspian region (the lower basins of the Black, Azov, and Caspian seas) is an evolutionary hotspot that harbors an unusual aquatic fauna particularly adapted to significant salinity fluctuations. Many of these adaptable species of crustaceans, fishes, mollusks, and annelids have invaded inland waters of the Northern Hemisphere over the past century, causing local extinctions of native species and restructuring of ecological communities. Of the invasive Ponto-Caspian species, amphipod crustaceans are the most numerous. Despite their noted negative impacts and the ever-increasing threat due to global warming, the factors that promote invasion success are incompletely understood, with increased fecundity and aggressivity thought to be important. It is also not known whether the aliens occupy the same ecological niche as the native species – if not, the replacement of native species with invasive ones might have a significant effect that would ripple throughout the ecosystem. The main aim of the proposed topic is to compare native and invasive Ponto-Caspian amphipods from Lithuanian inland waters in a multidisciplinary framework that would combine field research and laboratory experiments with functional morphology. Specifically, it seeks to understand (1) how amphipod morphology (e. g. body shape, size, and appendage length) is related to habitat preference, (2) how it influences the outcome of interspecific agonistic interactions and (3) predation by fish, and use it to test (4) if invasive species can trigger relatively rapid adaptation of native species. The results would significantly improve our understanding of the ecological niches of both the native and alien species and could also help predict the effects of the invaders that are expected to arrive in the future.

Ecology of the edible dormouse is rather well investigated in the core of its distribution range where these dormice live mainly in European beech (Fagus sylvatica) dominated forests. Lithuania is situated on the northern periphery of the dormouse range and outside the continuous range of the European beech. For this reason, habitats of the edible dormouse are completely different in this country, dormouse populations are comparatively very small. The edible dormouse is included in the Red Data book of Lithuania (EN category) and in the list of strictly protected species of the Republic of Lithuania. The protection plan for the edible dormouse is approved by the Ministry of Environment, in which scientific research aiming better protection of this species is foreseen. Only 10 populations of the edible dormouse are known in Lithuania now, and all of them will be investigated during the course of doctoral studies. Field studies will be carried out during summer time (July–August). Nocturnal counts of calling dormice will the main method of investigation, and official forestry inventory data will be used. All calling dormice recorded will be mapped. Habitat parameters determining presence of the edible dormouse in their localities will be estimated based on the results of nocturnal counts and official forestry inventory data. Areas of habitats suitable for this species will be estimated in all known localities. Population densities will be estimated in different forest stands according to nocturnal counts of calling dormice, and population size will be calculated. Anthropogenic impact on dormouse habitats will be evaluated in all localities of the edible dormouse, and necessary protective measures will be proposed. Based on the results of the studies, recommendations for protection of the edible dormouse in Lithuania will be prepared. Results of the doctoral studies will have both scientific and nature conservation significance.