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

In Lithuania, there are about 1,500 sites called hillforts, although not all of them are true ones (Zabiela, 2005). According to the data of the Department of Cultural Heritage under the Ministry of Culture, there are currently 931 hillforts registered in Lithuania, of which 209 have the status of state protected objects (Summary of the Register of Cultural Values, 2024). As most of the hillforts are maintained by state parks, they are not allowed to become overgrown with shrubs or forest, which results in relatively sustainable open habitats rich in economic plant species such as medicinal and aromatic plants, and crop wild relatives. This approach, which also conserves in situ biodiversity resources by protecting specific sites (in this case, archaeological heritage sites such as hillforts) outside the network of state protected areas, has recently been recognised internationally as an important concept – “Other effective area-based conservation measures” (OECM) (CBD, 2018). Although the research on economic plants on Lithuanian hillfort sites is still in its initial phase, it is already possible to predict its viability. Conservation planning of target species on hillfort sites largely avoids the conflicts of interest that are typical in other cases of land use. In addition, the coverage of some target species populations is significantly increased as hillforts’ distribution is quite wide across the country. One of the main research objectives within this theme is to assess at a national scale which economic plant species and at what population abundance can be effectively conserved on hillfort sites. This research would contribute to the implementation of the national biodiversity conservation strategy of Lithuania, as well as to a more comprehensive assessment of the country’s wild economic plant flora and to the improvement of the use of these resources.

Corn mint (Mentha arvensis, Lamiaceae), common in the middle-latitude climatic regions of Eurasia,is both a weed and a medicinal plant, the essential oil of which is included in the European Pharmacopoeia (European Pharmacopoeia, 2024). Plants of this species can intensively spread vegetatively as a weed with their creeping, abundant branched rhizomes and influence the growth and development of neighbouring plants through the allelopathically active biochemical compounds released from the underground parts into the soil. Due to gynodioecy characteristic of generative reproduction and intensive interspecific crossing, corn mint is characterized not only by a large interspecific diversity of morphological and anatomical features, but also by chemical polymorphism. Corn mint is the main source of natural origin menthol, widely used in food, pharmaceutical and other industries. This compound can make up to 80% of the essential oil of corn mint, but according to exploratory and unpublished research data, menthol has not been detected in plants of this species growing wild in Lithuania. Polymorphism is significantly influenced by the environment in which the plant grows. Therefore, the aim of the work should be to investigate the relationship between the corn mint polymorphism and environmental conditions, determining which chemotypes of corn mint are common in Lithuania and how this distribution depends on the environment. The allelopathic properties of different chemotypes of corn mint will also aim to determine.

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.

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.

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.

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.

The aim of the study is to investigate changes of host – parasite interactions in wild mammal populations in the gradient of increasing anthropogenic pressure.
The object of the study is mammals and their parasites. During this research, parasite diversity of various mammalian species will be investigated with special attention to zoonotic diseases. Factors shaping parasite communities in changing environment will be analysed. Obtained results will provide valuable information how changing environment affect host and parasite communities.

Amphipod crustaceans play a key role in macroinvertebrate communities and the diets of bentophagous fish in lakes. As part of global change, in many places, native amphipods are being displaced by the invasive ones from the Ponto-Caspian region (the lower basins of the Black and Caspian seas). In Lithuanian lakes, intentionally introduced alien amphipods have spread the most, but soon they will also have to face competition from the aggressive self-dispersed compatriot species. Temperature and dissolved oxygen should be investigated as the primary factors that determine the species’ competitiveness and the likely changes in the amphipod assemblages as the climate warms and lake productivity increases. In turn, amphipod species differ in their preferences to feed on plant detritus, filamentous algae, fine organics, or small animals. Shifts in their assemblages can thus lead to significant changes in lake functioning. This work aims to investigate the competitiveness, dietary preferences, and potential effects on lake functions of native and invasive amphipods that occur or are spreading across the lakes of our region under warming climate conditions. The topic foresees laboratory and field studies on the influence of temperature on oxygen consumption (1) and coexistence (2) of amphipod species, their feeding preferences (3), and the influence of amphipod assemblages on the functional structure of macroinvertebrate communities and the overall function of detritus shredding (4). The results will significantly contribute to the ecological knowledge of invasive species spreading across Europe and will help to predict shifts in amphipod assemblages as well as the associated ecosystem changes.