History of Laboratory

The Zoological Department of the Institute of Biology was founded in 1941 and reestablished in 1945. The main direction of scientific work was fauna inventory and reconstruction. In 1946–1955, faunistic research was not intensive. N. Likevičienė studied the murid rodents. In 1964, the Handbook of Mammals of the Lithuanian SSR was published (T. Ivanauskas, N. Likevičienė and S. Maldžiūnaitė). In 1956–1980, J. Prūsaitė and S. Maldžiūnaitė studied the fauna of canids, mustelids, ungulates and other game animals.

The Institute of Zoology and Parasitology is founded on 1 July 1959. The staff of the Vertebrate Zoology Branch of the Institute studied the fauna of terrestrial vertebrates and bird migration until 1963, the ecology and physiology of terrestrial vertebrates from 1964 to 1976, and the spatial distribution of mammals in different landscapes from 1974. The sector was headed by academician P. Šivickis (1959–1960), A. Vaitkevičius (1960–1964), professor J. Cukerzis (1964–1974), S. Maldžiūnaitė (1974–1977), and P. Bluzma (1977–1980).

In 1976, studies of the biotopic-seasonal distribution of mammals in various Lithuanian landscapes began: abundance and distribution of ungulates, beaver, and small mammals depending on the species’ biological characteristics and habitat. The types of winter pastures for cervids were distinguished, the spatial distribution of moose, red deer and roe deer in Lithuanian forests was studied (P. Bluzma, R. Baleišis, J. Prūsaitė, J. Tauginas), as well as the distribution and abundance of beavers (A. Mickus) and the abundance and distribution of small mammals in cultural pastures (S. Maldžiūnaitė, R. Mažeikytė).

In 1980, the Vertebrate Zoology Sector (headed by P. Bluzma) was transformed into the Laboratory of Theriology. Its staff carried out studies on the spatial distribution and abundance of mammals in different landscapes.

In 1979–1981, the dependence of mammal diet and spatial distribution on the ecological conditions of forests and agricultural areas was studied. It was found that the seasonal dynamics of roe deer diet is determined by the forest cover (J. Prūsaitė), the abundance and seasonal distribution in agricultural areas and the formation of the “field” ecotype of roe deer – by the structure of the landscapes (P. Bluzma, R. Baleišis). Seasonal mapping of the red deer trail system has revealed the high ecological plasticity of these animals and the specificity of their adaptations in intensively cultivated landscapes (L. Balčiauskas, J. Tauginas). The most important factors determining the distribution of beavers in forest water bodies and their damage to forest stands have been assessed (A. Mickus). The 3-year cycle of common vole abundance dynamics has been determined and the influence of fertilisation and other anthropogenic factors on its diet and distribution has been assessed (S. Maldžiūnaitė, R. Mažeikytė).

In 1982–1986, mammals from natural and cultivated habitats were studied. The structure of the dominant Lithuanian landscapes and its significance for the quality of animal habitats, their abundance and spatial distribution was assessed (P. Bluzma).Optimum conditions for roe deer were found to be found in hilly-morainic uplands, for red deer in clay plains, and for moose in sandy plains (P. Bluzma, R. Baleišis). The potential of the cluster analysis method for regionalisation of Lithuania according to the abundance of game animals was assessed (L. Balčiauskas). The abundance and distribution of game animals in agroforests was found to be influenced by their size, their location in the territory and the structure of phytocenoses (J. Tauginas). The seasonal distribution of pine martens in forest habitats has been studied (K. Baranauskas), the quality of beaver habitats has been assessed (A. Mickus), the diversity, abundance and distribution of small mammal species has been investigated (R. Mažeikytė), and the seasonality of hazel dormouse populations has been examined (R. Juškaitis).

In 1987–1988, it was found that the density of cervids was 1.5–2 times higher than the official statistics and that the abundance of forage in the forests did not correspond to the quality of the habitats (P. Bluzma, R. Baleišis). A model of the dependence between the density of deer populations and their spatial distribution has been developed (L. Balčiauskas), a biotelemetry method has been tested for the study of individual territories of deer (J. Tauginas), seasonal micro-migrations of moose have been clarified (R. Baleišis), and the seasonal features of the use of micro-habitats by roe deer and moose have been revealed (P. Bluzma, R. Baleišis).

The seasonal dynamics of the use of burrow sets by carnivores has been elucidated and the influence of badger activity on the functioning of burrow sets has been determined (K. Baranauskas). The spatial-fenetic structure of beaver populations in Lithuania has been investigated, phenotype frequencies in river basins have been found to vary (A. Ulevičius), a factorial analysis of the distribution of these mammals in sand plain water bodies has been carried out (L. Balčiauskas, A. Ulevičius), and the anthropogenic impact on the abundance and distribution of otters has been assessed (K. Baranauskas). The spatial-demographic structure of the populations of the hazel dormouse was investigated (R. Juškaitis).

The status of the teriofauna of protected areas and problemic regions (Ignalina NPP, Seaside region, Vilnius-Caunas problem area, etc.) was assessed. Recommendations were made for the regulation of ungulate abundance, selective hunting of game to improve the quality of their populations and the value of hunting trophies, the use of forest felling residues as game fodder, the bonitation of beavers’ habitats and the increase of their productivity, the protection and survey methods for otters (P. Bluzma, R. Baleišis, L. Balčiauskas, J. Tauginas, A. Mickus, K. Baranauskas, A. Ulevičius).

Publications: „Lietuvos kanopiniai žvėrys“ (R. Baleišis, P. Bluzma, L. Balčiauskas, 1987), „Teriologiniai tyrimai Lietuvoje“ (autorių kolektyvas, 1988), „Lietuvos fauna. Žinduoliai“ (autorių kolektyvas, 1988).

In 1989, the Institute of Zoology and Parasitology was reorganised into the Institute of Ecology. The Laboratory of Theriology remained in the Terrestrial Ecosystems Division and was later reorganised into the Theriology Sector. Since 1991, the topic of the sector has been ‘Structural-functional relationships between anthropogenised ecosystems and mammalian communities’. In 1994, the Ecosystem Biodiversity Sector (headed by L. Balčiauskas) separated from the Theriology Sector.

In the Theriology sector, the status of populations of rare and protected species (mountain hare, lynx, wolf) was evaluated, trends in their distribution and abundance dynamics were revealed; cadastral data on the model species beaver were collected, and typological-structural analyses of the hydrographical network of several districts were conducted. A concept for a terrestrial vertebrate cadastre covering a set of species distribution, population and ecological niche parameters was developed.

Together with Norwegian and Estonian scientists, clarified Lithuanian bat species diversity, abundance, distribution, places of concentration were assessed, 16 new locations for five species in the Lithuanian Red Data Books were found. The negative changes of anthropogenic factors on cervid populations were assessed. A new mammalian species in Lithuania, the sibling vole, was identified on the basis of craniometric characters and a set of chromosomes, and the abundance, breeding and distribution of this species in the landscapes of south-eastern, central and western Lithuania were clarified.

After 1996, the complex study “Establishment of a scientific basis for biodiversity assessment and cadastre of terrestrial ecosystems” brought together the potential of researchers from two entomological units and the Teriology and Biodiversity Sectors (V. Jonaitis, L. Balčiauskas). A list of animal cadastral indicators and a methodology for their determination were developed. Mapping of burrow colonies of carnivores was completed. Investigating the reasons for the decline in moose abundance, recommendations for their increase were prepared. The results of the fallow deer introduction were assessed. The biodiversity database has been updated with data on the biotopic structure and fragmentation of Lithuania. Biodiversity assessment indices for different animal groups were developed. Computerised ecologist workstations have been introduced in several municipalities for site biodiversity assessment, linked to a framework of species and site protection guidelines.

Publications: „Lietuvos kanopiniai žvėrys“, 2-asis leid. (1998), „Taurieji elniai ir augmenija Žagarės draustinyje“ (1998), „Lietuvos gamtinė įvairovė: Telšių rajonas“ (1998), „Lietuvos gamtinė įvairovė: Šalčininkų rajonas“ (1998), „Lietuvos žinduolių, varliagyvių ir roplių paplitimo atlasas“ (1997; 1999), „Lietuvos gamtinė įvairovė: Biržų rajonas“ (1999).

In 2000-2002, data from regional biodiversity surveys were analyzed, examining the distribution of terrestrial vertebrate species diversity in the country’s districts and in the areas of greatest biodiversity value. The surveys covered five Lithuanian reserves. The biotopic distribution of rare animal species, threats to their existence, similarities and differences in biodiversity between reserves were assessed.

Publications: „Mažeikių rajono gyvūnijos atlasas. 1990-2000“, „Lietuvos gamtinė aplinka“, „Proceedings of BLCI symposium Human dimensions of large carnivores in Baltic countries“.

In 2001-2004, complex ecological, biochemical, genetic and parasitological studies were continued in cooperation with Vytautas Magnus and Klaipėda Universities (L. Balčiauskas, R. Juškaitis, etc.), investigating the population and ecological structure of rodent fauna. The distribution of small mammals in different habitats, their infestation with protists and helminths, and the genetic diversity of rodents were evaluated. Population abundance, sex and age structure and breeding indices of aquatic rodents (water vole, beaver, muskrat) were assessed.

Publications: „Lietuvos kanopiniai žvėrys“, 3rd ed. (2002); „Lietuvos medžioklės trofėjų rejestras“ (2002); „Zoogeografija“ (2002), „Žinduolių pavadinimų žodynas“ (2002); „The fear of wolves: A review of wof attacks on humans“ (2002); „Nature in Northern Europe – Biodiversity in a changing environment“ (2002).

In 2003, the structure of the institution was transformed (reorganised into the VU Institute of Ecology). The Laboratory of Mammalian Ecology (ŽEL) was established in place of the Teriology and Ecosystem Biodiversity Branch, headed by L. Balčiauskas. Since 2010, the Laboratory of Mammalian Ecology is part of the Nature Research Centre.

In 2003–2007,  ŽEL task was: Investigate the diversity, abundance, biotopic distribution and diet patterns of mammals under changing land-use conditions, their acceptability and environmental impacts, and provide conservation measures and possible solutions to human conflicts in line with EU requirements.

In 2004, public attitudes towards wolves and lynx, their distribution, and the extent of damage to livestock producers in north-eastern Lithuania were assessed. The impact of wolves on deer populations in the regions of Lithuania was studied. The possibility of relocating free-ranging bison populations to enclosures was assessed and methodological recommendations for the implementation of such a programme were developed. It was found that nestboxes increases the population density of the hazel dormouse in commercially exploited forests. The diet of otters in the rivers of south-eastern Lithuania was analysed, the proportion of fish and amphibians in the diet was determined, and the overlapping dietary niche of otters and the American mink was identified. The use of artificial roosts by bats was assessed. Abundance and body size and weight patterns of the field vole were determined, as well as age- and sex-specific differences in mouse craniometric traits.

In 2005, changes in the diversity and abundance of small mammals during the succession of forested grasslands, changes in the populations of shrews in overgrown logging sites, the impact of forest cutting areas on the abundance of hazel dormice, the peculiarities of the urban teriofauna, otter diet in regulated rivers, the presence of beaver habitats in drainage canals, and the intensity of the fall migration of the Natusius‘s pipistrelle were assessed.

International projects included BIOFORUM, which examined biodiversity-related conflicts in EU countries, and BIOTER, involving the European Bison Specialist Network.

In 2006, the abundance of the wolf population was assessed and measures for population management and monitoring were proposed. The importance of culverts for animals on motorways in reducing accidents was investigated and recommendations were made to increase the efficiency of culverts and their design. A new species of hibernating bats in Lithuania, the particoloured bat, changing its hibernation range. Otter diet in fishery ponds investigated. Socio-economic studies on mammals and protected areas valuation continued. Genetic methods have been used to clarify the distribution of field vole phylogenetic mtDNA lineages in Lithuania and to better localise the contact zone and the distribution of the Central European phylogenetic mtDNA lineage.

In 2007, sections of national and regional roads were identified where protection measures (signs, fences and culverts) are needed to prevent traffic collisions with wild animals. The abundance of the lynx was determined and measures for population management, monitoring and protection were proposed. An assessment of otter distribution and population abundance has been initiated. Nestboxes for bats have been proposed to increase their occupancy by 80–90%. The significance of clear-felling and selective logging for hazel dormice and the impact of meadow-forest succession on small mammal community formation was assessed. Genetic methods were used to clarify the distribution of field vole phylogenetic mDNA lineages in Belarus, Latvia, Estonia and Russia (Karelia). In the study of the diet of the Lesser Spotted Eagle, the performance of two methods for characterising mammal remains was evaluated. The influence of old beaver habitats onto reclamation channels was analysed.

Publications: Ulevičius A., Juškaitis R. 2005. Lietuvos žinduolių pėdsakai ir kitos veiklos žymės.
Augustaitis A. … Mažeikytė R. ir kt. 2006. Sąlygiškai natūralių ekosistemų kompleksiškas monitoringas.

In 2008–2012, ŽEL topic was: To assess mammal fauna surveys and develop a strategic framework for the use, management and conservation of mammal populations.

In 2008, the abundance, distribution, reproductive rates, degree of habitat conservation, threats and conservation prospects of the raccon dog and otter populations were assessed, and proposals for population management were made. The abundance and community diversity of small mammals in ecotones adjacent to different types of water bodies and their importance in the diet of predators were investigated.

In 2009, new mammal species were found in Latvia (Microtus subterraneus) and Lithuania (Neomys anomalus), and the trend of the root vole in Lithuania over 50 years was investigated. The attraction of breeding colonies of Natusius‘s pipistrelles and common pipistrelles in forested areas has been clarified. It has been estimated that around 20,000 mammals of 20 species are hit on Lithuanian motorways each year. The use of odour deterrents has been shown to reduce by 40% the number of animals entering roads through gaps in fencing. A model of ungulate migration across the A1 and A2 motorways has been developed, which has provided recommendations for the construction of underpasses and green bridges for animals.

In 2010, it was established that the minimum viable wolf population size for Lithuania is 100 individuals, while the ecologically optimal population size is 150–250 individuals. The minimum number of denning sites could be 5–10, with 15 (10–20) being acceptable number. It has been estimated that there were about 300 wolves in Lithuania in winter 2010. It was confirmed by modelling that the recommended hunting quota of 50–60 individuals does not affect the viability of the population. A review of the status and conservation measures of the dormicse (Gliridae) in Europe and Lithuania was carried out.

In 2011, it was estimated that between 20–25 thousand animals are killed and not officially registered on Lithuanian main roads every year, which is about 20 times higher than the official figures. Public attitudes towards lynx population management measures were assessed. It was found that the acceptability of lethal control measures depended on the perception of the threat posed by lynx. Haplotype diversity and prevalence in Lithuania were assessed using the D-loop fragment of the mitochondrial DNA cytochrome b gene to investigate the genetic diversity of the raccoon dog.

Species Conservation Plans have been developed for the lynx, the common porpoise, the Nathusius’s pipistrelle, thepond bat and the Daubenton‘s bat, as well as 17 Action Plans for the implementation of conservation requirements for these species.

Publications: Juškaitis, R. 2008. The Common Dormouse Muscardinus avellanarius: Ecology, Population Structure and Dynamics. Institute of Ecology, Vilnius.

Juškaitis, R., Büchner, S. 2010. Die Haselmaus Muscardinus avellanarius. Die Neue Brehm-Bücherei, Bd. 670.

Andersone-Lilley, Ž., Balčiauskas, L., ir kt. 2010. Ungulates and their management in the Baltics (Estonia, Latvia and Lithuania). In: European ungulates and their management in the 21st century. Cambridge University Press, Cambridge.

Jedrzejewski, W., … Balciauskas, L., et al. 2010. Synthesizing wolf ecology and management in Eastern Europe: similarities and contrasts with North America. The world of wolves: new perspectives on ecology, behaviour and management. University of Calgary Press.

Juškaitis, R. 2010. Inkilų gyventojai: paukščiai, žinduoliai, bendruomeniniai vabzdžiai. Lututė, Kaunas.

In 2012–2016, ŽEL topic was “Studies on the status and changes in mammal populations to provide a scientific basis for the management and conservation of mammals”.

The genetic diversity of Lithuanian moose, lynx, wolves and raccoon dog was assessed in the European context, identifying Scandinavian and continental populations of moose, three populations of lynx and three genetic clusters of raccoon dog, the largest of which spans the whole of Central Europe. It has been shown that a possible boundary between two genetically distinct moose clusters runs through Lithuania. Habitat fragmentation has been shown to be particularly important for lynx, with selection affecting males and females differently. A spatial trend in wolf heterozygosity from south-western Europe (lowest genetic diversity) to north-eastern Europe (highest genetic diversity) has been identified. The Lithuanian wolf population is heterozygous, with no bottle-neck effect and no signs of hybridisation with dogs. The size of the central population of the raccoon dog (>1500 km) confirms the ability of this species to disperse over long distances and its homogeneous population structure. Presumably, the Finnish and Central raccoon dog populations have evolved from different groups of introduced animals.

Phylogeographic studies of the hazel dormouse over most of its range have shown that there are two distinct genetic lineages: in western Europe, and in central and northern Europe, the Balkans and Turkey. The Lithuanian hazel dormouse is genetically similar to the dormouse of Latvia, Poland and Germany.

In collaboration with foreign colleagues, a haplotype structure for the TRL2 (toll-like receptor) gene has been identified in 21 European bank vole populations. These populations diverge into 4 clusters that overlap with three mitochondrial lineages. The TRL2 haplotype structure pre-dates the separation of the mitochondrial lineages and has persisted in the species populations.

The status of wolves, lynx, brown bears and wolverines across Europe was analysed, proving that due to legislative protection measures, public acceptance of predators and a long period of political stability, most populations have recovered to early- or mid-20th century levels. These species are observed in a fragmented, human-altered and intensively used landscape. The increase in forest cover and the increased abundances of ungulates have played an important role. Conflicts between humans and predators are caused by their preying on domestic animals, but predators are also a reflection of political processes in society.

In Lithuania, a citizen science project has collected more than 800 observations of large carnivores, showing that wolf surveys underestimate the number of wolves, as well as miss the increase in the number and distribution of lynx. 10 action plans have been developed to regulate the abundance of invasive species, the raccon dog and the American mink.

Public opinion on the presence of bison in sub-optimal habitats in Central Lithuania, where a herd of free-ranging bison has lived for 40 years, was assessed. It was found that 85% of respondents have a positive opinion of them, but 47.4% would not tolerate them within 10 km of their homes. More than 60% of the population would support an increase in the number of bison and 51% would support their presence in the wild. Negative public opinion can be a limiting factor.

Using the method of connected scatterplot, the abundance and hunting of moose and red deer populations in Lithuanian regions, population trends in the country and in counties were analyzed. The impact of selective hunting on the quality of roe deer trophies in the Baltic States was assessed: selection led to the development of larger roe deer antlers in Lithuania.

The number and consequences of wildlife-vehicle accidents were analysed on all main roads and the most accident-prone national roads in Lithuania. The effectiveness of accident mitigation measures (wildlife fences, underpasses, horizontal barriers, ramps) was assessed. Identification of locations where accident reduction measures (due to accidents with wild animals) are most needed was dome and a list of priority measures was prepared. Recommendations were made on: (1) measures to be used at recommended green bridge locations; (2) the use of innovative road signs; (3) the use of chemical repellents; and (4) driver information.

An examination of the influence of the duration and height of seasonal spring flooding on the small mammal communities of floodplain grasslands showed that flooding maintains their diversity in grasslands and reedbeds, as high tides displace dominant species, favouring other ones.

Analysis of the effects of spontaneous and human-induced initial succession of grassland-forest on small mammals show, that succession results in a decrease in community species diversity and abundance, but no change in biomass due to substitution of dominant species.

An assessment of the impact of small Great Cormorant colonies on the abundance and species composition of small mammals found that the impact of biogenic pollution on active colonies in the area results in a significant reduction in species diversity. Aquatic ecosystem nutrients are transferred to small mammals through the food chain, accumulating δ13C and δ15N isotopes in their body.

The reproductive performance of the root vole has shown that the population in Lithuania belongs to the southern part of its geographical range, with a small litter size and a low number of litters per year. This species was first recorded in Latvia, close to the Lithuanian border. The geographical gradient of the size of the watter shrew in a north-south direction and its inconsistency with Bergman’s rule in the middle of the species’ range was analysed, and a significant northward range shift of the Medditeranean water shrew was found.

Summarising the data on the distribution, abundance and habitats of the striped field mouse and the pygmy field mouse, the pygmy field mouse is found only in the north-western and northern parts of Lithuania, where the species is characterised by the avoidance of forest habitats, the preference for ecotone habitats, and a comparatively small number of individuals.

Long-term data on changes in the abundance of the yellow-necked mouse in relation to the yield of large-seeded trees and shrubs are summarised, especially for oaks, which are more abundant and more regularly harvested than hazel.

2011-2015 Global grant “(Peculiarities of Gliridae populations in the north-western periphery of their ranges” (R. Juškaitis): data on the hazel dormouse throughout its range were summarised. New data on the abundance, demographic structure, reproduction, etc. of common dormouse, forest dormouse and fat dormouse populations in the north-western periphery of their ranges. An analysis of the diet and its dynamics during the season of the forest dormouse was carried out. The mortality of the hazel dormouse population and its impact on population dynamics was analysed. Data on the ecology of the hazel dormouse population at the north-western edge of its range were summarised.

Publications: Juškaitis, R., Büchner, S. 2013. The Hazel Dormouse: Muscardinus avellanarius. NBB English Edition, vol. 2. Hohenwarsleben: Westarp-Wissenschaften.

Holden-Musser, M.E., Juškaitis, R. & Musser, G.M. 2016. Family Gliridae (Dormice). In: Handbook of the Mammals of the World. Vol. 6. Lagomorphs and Rodents I. Barselona, Lynx Edicions.

In 2017–2021, ŽEL topic was: “Assess long-term changes in mammal species and populations due to climate change and other natural and anthropogenic drivers; complete datasets covering geographic and local gradients”.

New methods were used: citizen science, stable isotope and chemical element analysis, wildlife cameras. GIS analysis and KDE+ software have been applied to the study of mammal roadkill, to identify the most frequent hotspots of accidents involving ungulates. These data have been used in the work of the IENE network to assess the hotspots in Europe. In cooperation with partners from other Lithuanian and foreign institutions, studies on small mammal pathogens have been launched.

An analysis of long-term population trends of moose, wild boar, red deer, roe deer, brown bea, lynx, and wolf across nine countries found that the dynamics of these species were driven by the speed of the socio-economic changes that occurred following the end of socialism in the 1990s. Rapid population declines were typical of those post-socialist countries, including Lithuania, where reform was slow. During the economic downturn, game fauna is affected by poaching and overhunting. In countries where political and economic change is faster, fauna are less affected (Bragina et al., 2018).

The GIS model was used to assess moose migrations along two of the most heavily used main roads in Lithuania, and to identify the locations of the highest risk of car collisions with moose depending on habitat structure. The dynamics of road mortality time (seasonal, daily and hourly) of moose, red deer, roe deer and wild boar in 2002–2017 was analysed. Peaks of accidents were identified (1) in May and November, (2) on Fridays, (3) at 7.00 and 22.00. The most dangerous times have been shown to be before and after sunset: early morning and late evening in spring and summer, late morning and early evening in autumn and winter. This information is important for planning safety measures for encounters with ungulates and informing drivers.

Data collected during the Citizen Science Project in 2015–2018 on the distribution of large carnivores in Lithuania showed that the wolf population is expanding and increasing. In 2018, there were at least 500 individuals (100 groups) in Lithuania, the average group size increased to 3.6 individuals, and the proportion of individual wolves in the population decreased from 56% in 2015 to 40% in 2018. An increase in the distribution and abundance of lynx was also observed, with 33 recorded cases of lynx being observed not alone (usually a female with one, two or even three cubs). Lynx litters were observed throughout Lithuania.

Seasonal and diurnal changes in the activity of carnivores and ungulates in two colonies of Great Cormorants differing in the abundance of breeding birds were determined. The patterns of accumulation of 20 chemical elements in the body of small mammal species dominating cormorant colonies were investigated.

Stable carbon and nitrogen isotope analyses assessed how niche partitioning occurs in the small mammal community over time (changes in dominance) and isotopic space (differences in diet). The uniqueness of the floodplain habitat for the formation of a high species diversity community was clarified. Stable δ13C and δ15N isotope values in the hairs of grey voles sympatrically living in commercial gardens and orchards showed that the widest trophic niche was characteristic of the dominant species, the common vole. The three grey vole species examined shared a trophic niche for δ15N in all habitats, but for δ13C in the garden and grassland habitats the niches were distinct.

Sexual dimorphism, variation in morphometric and craniometric dimensions, and geographical size gradients (north-south, east-west, altitude) within the range of the Lithuanian pygmy field mouse and the correspondence with Bergman’s and Murphy’s Laws were assessed. Changes in body and skull size of the field vole in relation to latitude and time were analysed by comparing Lithuanian and Estonian populations and the years 1980–1996 and 2014–2016. A significant reduction of individuals in Estonia was found (23 out of 27 dimensions reliably reduced to 21.9%). Changes in the size of Lithuanian voles were ambiguous.

The diversity and abundance of small mammals in commercial orchards and berry plantations and their dependence on habitat and the intensity of orchard management were investigated. It was recommended to use the common vole as a reference species for the registration of plant protection products in Lithuania.

Long-term changes in the spatial structure of the hazel dormouse population as a function of population density were analysed, and it was found that as population density decreased, the average size of the individual areas increased and overlap decreased, but that the changes in localisation were independent of population density. The analysis of data from 2000 to 2019 showed that the negative effects of clear-felling on the abundance of hazel dormice in the logging area are short-lived. Clear-cutting in small forest areas is favourable for hazel dormouse populations. The dynamics of the abundance and demographic structure of the subpopulation of the forest dormouse between 1999 and 2019 shows that the subpopulation has disappeared due to deforestation, which has completely destroyed part of the dormouse habitat and severely degraded the quality of the remaining habitat, and due to an unfavourable sex ratio (since 2015, there are no more males).

For the first time in Lithuania, rickettsiae were found in small mammals during the study of small mammal pathogens (Radzijevskaja et al., 2018). Rat hepatitis E virus was found in grey and black rats (Simanavičius et al., 2018). Puumala virus was detected for the first time in Lithuania in brown voles (Strakova et al., 2017).A new strain of hantavirus, named Rusnė virus, was found in eight root voles from Rusnė (Dreves et al., 2021).

The 2022-2026 ŽEL objective is: “To investigate the impact of changes in mammal abundance and species diversity on ecosystems and their functions in a historical context, and to provide perspectives for the rational use of their resources”. The aim of the research: systematic assessment of protected, invasive and game mammal species, populations and their habitats for their conservation and use, analysis and prediction of the impact of climate change and anthropogenic stresses, retrospective assessment and prediction of changes in small mammal communities in different habitats, and studies on parasite-host interactions.

Dissertations defended by Laboratory staff (1961–2023)

Prūsaitė J. „Lietuvos Canidae šeimos žvėrys / Canidae of Lithuania“ (1961)

Maldžiūnaitė S. „Lietuvos TSR kiauniniai plėšrūnai, jų biologija, gausumas ir ūkinė reikšmė / Mustelid predators of the Lithuanian SSR, their biology, abundance and economic importance“ (1964)

Baleišis R. „Lietuvos TSR briedžių biologija ir reikšmė miškų ūkiui / Biology of moose in the Lithuanian SSR and their significance for forestry ” (1973)

Bluzma P. „Stirna Lietuvoje (ekologinė-morfologinė charakteristika) / Roe deer in Lithuania (ecological-morphological characteristics)“ (1975)

Mažeikytė R. „Pelinių graužikų populiacijų radiojautrumo pokyčiai dėl jų gyvenamųjų vietų užteršimo 90Sr / Changes in the radiosensitivity of populations of murid rodents as a result of 90Sr contamination of their habitats“ (1978)

Baranauskas K. „Paros ir sezoniniai mitotiniai ritmai geltonkaklės pelės ir paprastojo pelėno akies raginės epitelyje / Diurnal and seasonal mitotic rhythms in the corneal epithelium of the yellow-necked mouse and the common vole“ (1984)

Tauginas J. „Elninių erdvinis pasiskirstymas antropogeninės miško sukcesijos sąlygomis / Spatial distribution of deer under anthropogenic forest succession“ (1985)

Balčiauskas L. „Kanopinių erdvinė struktūra Lietuvos antropogeninio landšafto sąlygomis / Spatial structure of ungulates in the Lithuanian anthropogenic landscape“ (1988)

Juškaitis R. „Lazdyninės miegapelės populiacijų struktūra ir biocenotiniai ryšiai Lietuvoje / Population structure and biocenotic relationships of the Hazel Dormouse in Lithuania“ (1990)

Ulevičius A. „Bebro (Castor fiber L.) populiacijos formavimasis ir erdvinė-fenetinė struktūra Lietuvoje / Population formation and spatial-fenetic structure of beaver (Castor fiber L.) in Lithuania“ (1993)

Baltrūnaitė L. „Vidutinio dydžio plėšriųjų žinduolių ekologinės nišos Lietuvos ekosistemose / Ecological niches of medium-sized carnivores in Lithuanian ecosystems“ (2003)

Balčiauskienė L. „Naminės pelėdos (Strix aluco) ir mažojo apuoko (Asio otus) mitybos ekologija, vertinant pagal grobio kraniometriją / Feeding ecology of Tawny owl (Strix aluco) and long-eared owl (Asio otus) based on craniometry of prey” (2006)

Jasiulionis, M. „Didžiojo kormorano (Phalacrocorax carbo sinensis) kolonijų poveikis žinduoliams / Impact of the colonies of great cormorants (Phalacrocorax carbo sinensis) on mammals” (2020)

Kučas, A. „Laukinių gyvūnų susidūrimų su transportu dėsningumai ir susidūrimų mažinimo priemonių vertinimas / Evaluation of wildlife–vehicle collision patterns and assessment of mitigation measures” (2021)

Kitrytė, N. „Smulkiųjų žinduolių parazitų įvairovė ir jų bendrijas formuojantys faktoriai /Diversity of small mammal parasites and factors shaping their communities” (2022)

Stirkė, V. „Smulkiųjų žinduolių ekologijos ypatumai komerciniuose soduose, uogynuose ir komensalinėse buveinėse / Peculiarities of small mammal ecology in commercial orchards, berry plantations and comensal habitats” (2023)