Muscardinus Research Articles

A systematic scanning method to locate cryptic terrestrial species

When studying wild animals, consideration must be given to potential detrimental effects of the study technique, particularly if techniques may affect behaviour or energy expenditure. Many small terrestrial species occupy cryptic habitats, the characteristics and locations of which may be poorly understood. To study these habitats, researchers must be able to locate them, but must also consider the potential for disturbance of the organisms and the impacts this may have. Here, we developed and tested a novel, non-invasive method of locating the cryptic hibernation nests of passive integrated transponder (PIT) tagged hazel dormice Muscardinus avellanarius. The use of a powerful PIT tag scanner combined with a systematic search technique resulted in the location of nine wild hibernating dormice. Camera trap recordings indicated no external dormouse activity following detections, indicating minimal disturbance. In addition, eleven PIT tags no longer inside a dormouse were detected on the forest floor during searches. This study demonstrates a non-invasive alternative to techniques such as radio-collaring for small mammals, and highlights potential uses of PIT tags in research beyond identification of individuals, particularly in understanding fine-scale habitat selection.-A systematic search method enabled location of cryptic terrestrial species-The use of PIT tags allows detection with minimal disturbance

Development of a microfluidic SNP assay for lineage discrimination in the endangered hazel dormouse

AbstractThe application of Genotyping-by-Sequencing (GBS) approaches is often restricted in wildlife monitoring and conservation genetics, as those fields often rely on noninvasively collected samples with low DNA content. Here we selected a subset of informative single-nucleotide polymorphisms (SNPs) from genome-wide data for lineage discrimination of a locally endangered Eurasian rodent, the hazel dormouse (Muscardinus avellanarius), and designed a microfluidic 96 SNP genotyping assay suitable for noninvasively collected samples. Analyses of 43 samples from different European countries confirmed successful discrimination of the Eastern and Western lineage and local substructure within those lineages, proving the suitability of the developed panel for identifying evolutionary significant units and conservation units. Application with 94 hair and scat samples collected in a recent monitoring study on the hazel dormouse in Southern Germany resulted in > 99.5% amplification success showing the applicability of the new tool in genetic wildlife monitoring and conservation studies.

Hibernation nest site selection but not overwinter activity is associated with microclimatic conditions in a hibernating mammal

Fine-scale variation in microclimates between habitats may impact energy consumption for the organisms that inhabit them. This may be particularly important for sedentary species or those unable to change habitats for long periods, such as hibernators. Low ambient temperatures were traditionally thought key to microclimatic selection for hibernation locations, but recent research suggests that other factors may contribute or exceed ambient temperature in importance. We aimed to characterise microclimates at hibernacula of wild hibernating hazel dormice Muscardinus avellanarius, and test how these microclimates differ to those at locations without hibernacula using a microclimatic modelling approach. Dormice hibernated in areas with warmer soil temperatures and lower variability in humidity and relative shortwave radiation. These results add to the growing body of evidence that low ambient temperatures may not be the primary driver of hibernation microclimate selection, although temperature is still likely to play an important role. We also found that ambient temperatures measured at the microclimatic level were substantially buffered compared to point samples taken at the nearest weather station (∼1.6 km away), highlighting the importance of considering microclimates in wildlife conservation in the face of future environmental change.

Investigating the use of artificial nest boxes positioned at different heights on trees and in isolated positions by dormice (Muscardinus avellanarius): Implications for current survey guidelines

Abstract This research, carried out in two phases, is a response to questions raised regarding the validity of surveys based on artificial nest boxes, positioned at around 1.4 m from ground level, to determine the presence of dormice (Muscardinus avellanarius). This species is generally considered to be an arboreal mammal that visits the ground infrequently other than for winter hibernation. In Phase 1, artificial nest boxes were positioned high in the tree canopy and at standard height on the same tree. The presence of leaves and material from the woodland floor in nests informed the design of Phase 2 with the inclusion of a third box, on an isolated post with no arboreal connectivity, carried out on a different site. Results demonstrate the presence of dormice and their nests in artificial nest boxes positioned in the tree canopy, at conventional height and on isolated posts with no arboreal connectivity. This suggests that the current method of surveying for dormice using boxes at around 1.4 m from ground level may not result in robust ‘likely absence’ conclusions for surveys aimed at determining the presence of dormice on a site. Previous experience of long‐term surveys has indicated that use of artificial next boxes declines with age of box. This was confirmed over the 6 years of the second project reported here. While often taken to indicate decline in population alternative explanations are proposed and this is highlighted as requiring further investigation. The apparent decline of hazel dormice and the contraction of their range is evidenced by surveys carried out according to current ‘good practice’ guidance. The results of this research suggest that these should be reviewed and revised to ensure conservation objectives are being met.

Variation in hazel dormouse (Muscardinus avellanarius) presence in hedge and scrub habitats

Abstract Habitat restoration at a landscape scale is key to reversing the loss of biodiversity arising from habitat destruction. In landscapes that are intensively used by people, such as for agriculture, valuable restoration efforts might be applied not just to ‘prime’ habitats that are known to have strong associations with target species, but also to ‘sub‐prime’ habitats that might nevertheless provide sufficient resources to support populations. Hazel dormouse (Muscardinus avellanarius) populations are in chronic decline in the UK. The species is typically associated with broadleaf woodland but restoration of this habitat at scale in agricultural landscapes is difficult. Other habitats used by dormice might, therefore, provide opportunities for restoration. We investigated the use by hazel dormice of hedgerow and scrub habitats in southwest England. From June–November 2022, using footprint‐recording tunnels, we surveyed 38 hedges and 21 scrub patches in the vicinity of 18 sites known to contain established dormouse populations. We found that dormice were frequently present in scrub (9.3 detections per 100 tunnel checks, 95% confidence interval 6.6–12.0) and less frequently in hedges (4.5 detections, 95% CI 3.2–5.8). In scrub patches, dormice were present more frequently as the abundance of dormice in the closest population increased, and less frequently where bracken (Pteridium aquilinum) was dominant. In hedges, dormice were detected more frequently where there was abundant hazel (Corylus avellana) and honeysuckle (Lonicera periclymenum), as frequency of intersections with other hedges increased, and where an earthen bank was not present. Understanding hazel dormouse association with a wide range of habitats, particularly scrub, offers more opportunities for habitat restoration as part of species conservation strategies.

Machine learning identification of microhabitat features associated with occupancy of artificial nestboxes by hazel dormice Muscardinus avellanarius in a UK woodland site

Hazel dormice Muscardinus avellanarius have severely declined since 2000 leading to increased legislative protection in the UK and Europe. Artificial nestboxes are widely used for its conservation and monitoring. Previous research has focused on how to identify suitable areas for nestboxes, but where to place individual boxes to promote occupancy is less well understood. Here, we demonstrate the use of machine learning Random Forest regression to predict nestbox occupancy from a wide range of microhabitat variables using a UK woodland as a case study. Random forest models are powerful predictive tools that allow simultaneous testing of many predictors with relatively few observations.Field data included observed nestbox occupancy (2017–2021) and measurements of 76 microhabitat variables collected in the summer of 2021 from 45 occupied and unused nestboxes located in a deciduous woodland in Berkshire, UK. We applied Random Forest regression to identify important variables and predict nestbox occupancy demonstrating robust approaches to tune model hyperparameters and evaluate importance metrics.In our study area, nestboxes were more likely to be occupied in sites with more hazel Corylus avellana, greater overall tree abundance but not fully closed canopies (optimal 80–85%), more honeysuckle Lolium periclymenum and hawthorn Crataegus monogyna, and when located further from footpaths and woodland margins. Occupancy over the study period was well predicted using microhabitat variables (13.3% OOB error) but future occupancy was more uncertain (33.3% error for 2021–2023 records).Modelling approaches that allow consideration of numerous variables from few locations or observations can be help identify relevant features and predict desirable outcomes of conservation actions. Here we demonstrate this approach identifying microhabitat variables that influence artificial nestbox occupancy by hazel dormice in a UK woodland. Findings offer some recommendations for local management that could promote nestbox occupancy and improve monitoring and conservation efforts.

Prevalence and Molecular Analysis of Encephalomyocarditis Virus-2 in the Hazel Dormouse.

The hazel dormouse (Muscardinus avellanarius) population in the UK continues to decline due to habitat loss, despite reintroductions of captive-bred individuals being conducted nationally for over 30years. Disease surveillance of captive-bred and wild dormice is performed to identify novel and existing disease threats which could impact populations. In this study, we firstly investigated cause of death in seven hazel dormice found dead in England, through next-generation sequencing identifying a virus closely related to a wood mouse encephalomyocarditis virus-2 (EMCV-2). Subsequently, lung tissue samples from 35 out of 44 hazel dormice tested positive for EMCV-2 RNA using a reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and Sanger sequencing methods developed in this study. Formalin-fixed tissues available for nine hazel dormice which tested positive for EMCV-2 RNA were examined microscopically. Three cases showed moderate interstitial pneumonia with minimal to mild lymphoplasmacytic myocarditis, but no evidence of encephalitis. However, the presence of possible alternative causes of death in these cases means that the lesions cannot be definitively attributed to EMCV-2. Here, we report the first detection of EMCV-2 in hazel dormice and conclude that EMCV-2 is likely to be endemic in the hazel dormouse population in England and may be associated with clinical disease.

Threat assessment for dormice in Latvia – facts and assumptions (Rodentia: Gliridae)

In Latvia, dormice were one of the less studied mammal taxonomic groups until the 21st century, due to their elusive way of life. Historical threat assessments of dormouse species conducted in the 1970s and 1990s were constrained by a scarcity of observations, primarily relying on accidental encounters. In 2021, a comprehensive reassessment of the threat status of four dormouse species recorded in Latvia – Glis glis, Eliomys quercinus, Dryomys nitedula, and Muscardinus avellanarius – was initiated, by applying the methodological framework developed by the International Union for Conservation of Nature (IUCN). Here we evaluate the outcomes of these reassessments in the context of previous threat assessments at the national level as well as in the regional context. Historical and current species status in neighbouring countries, as well as necessary protective measures in Latvia were also considered.

Small mammals near Janowiec nad Wisłą (middle-eastern Poland) on the basis of prey composition of the tawny owl Strix aluco and long-eared owl Asio otus

At two sites near Janowiec nad Wisłą (middle-eastern Poland) the species composition of a small mammal community in the diet of the tawny owl Strix aluco and long-eared owl Asio otus has been examined. The bones of 128 mammals have been extracted from S. aluco pellets gathered in the years 2014-2015, whereas 401 mammals have been extracted from A. otus pellets collected in the years 2023-2024. Dominant species in the diet of S. aluco (the site bordering woodland) were Clethrionomys glareolus (31.3%), Apodemus agrarius (16.4%) and Apodemus flavicollis (12.5%), while in the case of A. otus (the site bordering open landscape) Microtus arvalis (55.1%) appeared most frequent. Altogether 16 species were recorded representing: Soricomorpha (4), Chiroptera (1), Rodentia (10) and Carnivora (1). Two bats caught as prey belonged to the species of Myotis nattereri, common in this part of Poland. Most interesting species were Crocidura leucodon, whose recorded sites are near its range limit, and Muscardinus avellanarius – the species infrequently recorded in central and eastern Poland.

Nest box occupancy dynamics by hazel dormice (Muscardinus avellanarius) in central-western Romania

The hazel dormouse, Muscardinus avellanarius is a vulnerable and protected species that is challenging to study due to its specific way of life. Limited data on its distribution and population parameters are available for Romania. We collected data regarding species’ biology and ecology in the hilly areas of central-western Romania, within deciduous forests dominated by oak or beech species. We regularly monitored 80 wooden nestboxes, which served as shelter and breeding sites for the species, to assess the seasonal and sex-related variations in nest box usage. The highest occupancy levels were observed during the autumn, with a smaller peak in the spring. Males occupied more nest boxes than females, although the difference was not statistically significant. They also travelled greater distances. Most nest boxes were occupied by a single individual at a time. Recapture rates did not differ significantly between males and females, and most individuals were recaptured only once. Hazel dormice showed a high level of site fidelity, often returning to the same nestbox or one nearby. Interestingly, 14% of the females bred twice a year, which is a lower percentage compared to findings from other studies. Nest box occupancy rates in this region were also lower than those reported in other areas. However, it is important to note that these variations may be attributed to differences in methodology. The occupancy rate declined with the increased presence of the larger species, the fat dormouse Glis glis, which outcompeted the hazel dormouse.

The importance of urban areas in supporting vulnerable and endangered mammals

The fragmentation of habitats associated with urbanisation poses a significant threat to already vulnerable and endangered mammal species. While the county of Dorset has been identified as one of the UK’s biodiversity hotspots, it is characterised by large-scale urbanisation and intensive agriculture. Focusing on the largest urban area of Dorset—the conurbation of Bournemouth, Christchurch, and Poole—this study aims to investigate the importance of urban areas in supporting vulnerable and endangered mammals by comparing it to four other major land cover categories in the county: arable & horticulture, grassland, woodland, and heathland. The study utilises data collected by the county’s environmental records department through mainly volunteer-contributed ad-hoc sighting data of 10 872 georeferenced mammal records collected between 2000 and 2018. Our findings reveal that, despite having significantly different mammal communities to all other land covers, urban land cover was shown to host four out of five of the vulnerable and endangered species recorded in this study. These included the European rabbit (vulnerable on the IUCN red list), hazel dormouse (vulnerable on the UK red list), West European hedgehog (vulnerable on the UK red list) and European water vole (endangered on the UK red list). Our findings highlight the significance of urban areas as important habitats for mammal biodiversity, presenting an opportunity for the conservation of specific vulnerable and endangered species. Despite limitations in ad-hoc sighting data, our analysis indicates an overrepresentation of certain 'charismatic' species, like foxes and hedgehogs, in urban samples, likely due to their high intrinsic value to the population. While the recognition of urban habitats for 'red list' species is growing, it is also important to acknowledge the relative importance of charismatic species to urban human communities in conservation and management strategies.

Communities of Uropodina (Acari: Mesostigmata) in Nest Boxes Inhabited by Dormice (Glis glis and Muscardinus avellanarius) and Differences in Percentages of Nidicoles in Nests of Various Hosts.

Bird and mammal nests and nest boxes constitute microenvironments in which various groups of invertebrates can live, including mites from the suborder Uropodina (Acari: Mesostigmata). The main aim of the current study was to ascertain the characteristics of mite communities from the suborder Uropodina, which inhabit the nests of dormice (Gliridae) built in nest boxes. The second aim of the study was to compare the habitat preferences of Leiodinychus orbicularis (C. L. Koch) and Apionoseius infirmus (Berlese), i.e., two typically nest-dwelling species of Uropodina. The material for the study was collected from nest boxes in six forest complexes in southwestern Poland. The conducted research revealed the presence of five species of Uropodina, with a total number of 559 specimens, in the examined boxes. Leiodinychus orbicularis was found in almost half of all of the examined boxes and was a superdominant species in the communities. The analysis of the habitat preferences of the two nest species of Uropodina showed that A. infirmus preferred old natural nests, in which the communities were formed from a larger number of species, without a significant statistical prevalence of one species. On the other hand, L. orbicularis occurred sporadically in open bird nests, but was very numerous and frequent in nest boxes. The significant dominance of L. orbicularis in nest boxes can probably be explained by the specific conditions prevailing in this type of microhabitat, including the very low humidity and food resources that this mite species prefers compared to other species of Uropodina.

The genome sequence of the hazel dormouse, Muscardinus avellanarius (Linnaeus, 1758).

We present a genome assembly from an individual male Muscardinus avellanarius (the hazel dormouse; Chordata; Mammalia; Rodentia; Gliridae). The genome sequence is 2,497.5 megabases in span. Most of the assembly is scaffolded into 24 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 16.73 kilobases in length.

Using high-resolution LiDAR-derived canopy structure and topography to characterise hibernaculum locations of the hazel dormouse

The hazel dormouse is predominantly an arboreal species that moves down to the ground to hibernate in the autumn in temperate parts of its distributional ranges at locations not yet well understood. The main objective of this study is to test whether environmental characteristics surrounding hazel dormouse hibernacula can be identified using high-resolution remote sensing and data collected in situ. To achieve this, remotely sensed variables, including canopy height and cover, topographic slope, sky view, solar radiation and cold air drainage, were modelled around 83 dormouse hibernacula in England (n = 62) and the Netherlands (n = 21), and environmental characteristics that may be favoured by pre-hibernating dormice were identified. Data on leaf litter depth, temperature, canopy cover and distance to the nearest tree were collected in situ and analysed at hibernaculum locations in England. The findings indicated that remotely sensed data were effective in identifying attributes surrounding the locations of dormouse hibernacula and when compared to in situ information, provided more conclusive results. This study suggests that remotely sensed topographic slope, canopy height and sky view have an influence on hazel dormice choosing suitable locations to hibernate; whilst in situ data suggested that average daily mean temperature at the hibernaculum may also have an effect. Remote sensing proved capable of identifying localised environmental characteristics in the wider landscape that may be important for hibernating dormice. This study proposes that this method can provide a novel progression from habitat modelling to conservation management for the hazel dormouse, as well as other species using habitats where topography and vegetation structure influence fine-resolution favourability.

An evaluation of the macro anatomy of the Hazel Dormouse’s (Muscardinus avellanarius Linnaeus, 1758) (Rodentia: Mammalia) skeletal system in Türkiye

Muscardinus avellanarius, one of the thirty species of the Gliridae family, is found in areas covered with deciduous forests, with a range stretching from Bursa (Uludağ) to Trabzon in Türkiye. Hazel Dormouse, classified as an endangered species and characterized by their deep hibernation patterns, possess significant value as bioindicators of environmental change. In this study, a macro-anatomical evaluation of the skeletal structure of forty-six specimens collected from the Eastern and Western Black Sea Regions between 1979 and 1983 were conducted. The evaluation revealed that the whole skeleton of Muscardinus avellanarius consisted of 225 bones. The morphometric variances and variations between the Eastern Black Sea and Western Black Sea specimens were detected by defining the skull and baculum bones that hold taxonomic value.

A record of a melanistic forest dormouse Dryomys nitedula in Lithuania, with a review of colour anomalies in dormice (Gliridae)

A melanistic forest dormouse Dryomys nitedula was recorded among 125 individuals marked in a small isolated local population in central Lithuania. Until now, a totally black individual of D. nitedula was captured only in western Ukraine. A review of the literature on colour anomalies in European dormouse species has shown that this phenomenon is rare in dormice. Several black hazel dormice Muscardinus avellanarius were recorded in the same locality in northern Germany in 1972 and 2015, and one such dormouse was captured in the UK. Partial albino M. avellanarius was recorded in Germany. Two melanistic garden dormice Eliomys quercinus were collected in the Czech Republic, an albino specimen in France and a flavistic specimen in Germany. In the edible dormouse Glis glis, melanistic, albino, isabelline and flavistic individuals were recorded, all from Slovenia and the Czech Republic. Among aberrant-coloured European dormice, melanistic individuals were documented most often. Tail-tip albinism is more frequent among M. avellanarius, and this trait was recorded in several countries.

Cover Picture and Issue Information

Ecological Solutions and EvidenceVolume 4, Issue 2 e12152 COVER PICTURE AND ISSUE INFORMATIONFree Access Cover Picture and Issue Information First published: 03 April 2023 https://doi.org/10.1002/2688-8319.12152AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Cover image: A hazel dormouse, a species in chronic decline with uncertain threat status, forages in a hazel tree © John Webley Volume4, Issue2April–June 2023e12152 RelatedInformation

Nest material preferences in wild hazel dormice Muscardinus avellanarius: testing predictions from optimal foraging theory.

Obtaining nesting material presents an optimal foraging problem, collection of materials incurs a cost in terms of risk of predation and energy spent and individuals must balance these costs with the benefits of using that material in the nest. The hazel dormouse, Muscardinus avellanarius is an endangered British mammal in which both sexes build nests. However, whether material used in their construction follows the predictions of optimal foraging theory is unknown. Here, we analyze the use of nesting materials in forty two breeding nests from six locations in Southwest England. Nests were characterized in terms of which plants were used, the relative amount of each plant, and how far away the nearest source was. We found that dormice exhibit a preference for plants closer to the nest, but that the distance they are prepared to travel depends on the plant species. Dormice traveled further to collect honeysuckle Lonicera periclymenum, oak Quercus robur, and beech Fagus sylvatica than any other plants. Distance did not affect the relative amount used, although the proportion of honeysuckle in nests was highest, and more effort was expended collecting honeysuckle, beech, bramble Rubus fruticosus and oak compared to other plants. Our results suggest that not all aspects of optimal foraging theory apply to nest material collection. However, optimal foraging theory is a useful model to examine nest material collection, providing testable predictions. As found previously honeysuckle is important as a nesting material and its presence should be taken account when assessing suitability of sites for dormice.

Selection of Nest Material and Summer Nest Location by the Hazel Dormouse (Muscardinus avellanarius) in the Bidstrup Forests, Denmark.

Hazel dormice (Muscardinus avellanarius) construct summer nests for resting and breeding. The nests are built directly in the vegetation, in tree hollows, or in nest boxes. The availability of nest materials and vegetation coverage may affect the likelihood of finding hazel dormice at a location. The aim of the study is: (1) To investigate the preferences of hazel dormice for nesting materials today compared to four decades ago. (2) To investigate hazel dormice preferences for vegetation coverage at nest sites. In total, 148 hazel dormouse summer nests from the Bidstrup forests in Zealand (Denmark), were analysed. Of these, 82 were collected in the period A: 1980-1985 and 66 were collected in B: 2019-2020. In total 26 different nest materials were found. Beech was the major nest material in both periods, and Jacob's selectivity index indicates that beech is selected for as nesting material and that hazel dormice may travel to collect beech leaves. Nests from period A contained more beech (W = 1521, p < 0.05) and less oak (W = 1304, p < 0.01) compared to nests from period B. Vegetation analysis showed that coverage of shrubs higher than 2 m above ground (W = 1.5, p = 0.07) may be of great importance for hazel dormice.

The importance of shape analysis of the first upper molar in the separation of two subspecies of the Hazel dormouse (Muscardinus avellanarius (Linnaeus, 1758)) in Northern Anatolia

Morphological features are important for intraspecific and interspecific variation. Teeth are important taxonomical characteristics because they can differ according to diet. Shape analysis of the first upper molar (M1) was used to determine geographical variations and effects of ecological changes on the population structure of Hazel dormice (Muscardinus avellanarius) living in Turkey. Both outline and landmark analysis, as well as a canonical variates analysis, showed significant differences in teeth shape between populations. With this technique, we separated out two subspecies: M. a. trapezius and M. a. abanticus.