Muscardinus Research Articles

Displacing and translocating hazel dormice (Muscardinus avellanarius) as road development mitigation measures

Road development can remove valuable wildlife habitat and reduce habitat connectivity. Where such works impact on European Protected Species in the UK, such as hazel dormice (Muscardinus avellanarius), mitigation is required to satisfy the relevant Statutory Nature Conservation Organisation licensing process. The study described here concerns the removal of dense road verge landscape planting occupied by hazel dormice prior to the construction of a new road junction and slip roads on a dual carriageway in Wales. Pre-construction monitoring started in May 2007, followed by vegetation clearance between August and September. Dormice were displaced into retained habitat through maximum daily vegetation clearance of 30 m lengths (varying widths), in parallel with translocation. This process resulted in the discovery of 48 natural (i.e. not within a nest box) dormouse nests, and the capture of 29 dormice for translocation; 90% were successfully released. Whilst within soft-release cages prior to release, dormice preferred a diet of blackberries (Rubus fruticosus agg.) and freshly picked hazel (Corylus avellana) nuts, prompting a recommendation for early Autumn (mid-August – September) as the ideal translocation season. Other recommendations for displacing and translocating dormice are provided, albeit limited in the absence of comprehensive pre-construction, and post-translocation monitoring.

Habitat Fragmentation of Two Dormouse Species (Gliridae, Rodentia) and Biodiversity Protection of Deciduous Forests in the Nizhny Novgorod Region

Little is known about the dormouse species distribution in the Middle Volga region. The habitats of the edible dormouse Glis glis L. and the hazel dormouse Muscardinus avellanarius L. are fragmented and mainly lost in the agricultural landscape of the right Bank of the Volga River and in the coniferous forests of the right Bank of the Lower Oka River in the Nizhny Novgorod region. New data are given of features of the habitats of two sympatric dormouse species at a patch of a lime-oak forest surrounded by coniferous forests. Within the studied area, 80 wooden nestboxes were put up in places with well-connected tree canopies and well-developed understory. During three years of our study (2016-2018), preliminary data were obtained on the dynamics of nest-boxes use, relative abundance and reproduction of both dormouse species. The patch of the lime-oak forest, about 20 ha, is divided into two parts by a road and a 50 m-wide vista. Both parts did not differ in vegetation, but the edible dormouse was found in the southern part only. The hazel dormouse was found through the whole lime-oak patch, except for the woodplot no 1 (1.5 ha) occupied by edible dormice with a high density. On the basis of the data obtained, management actions are suggested to raise the level of connectivity and immigration in the population of isolated broad-leaved patches in coniferous forests, in particular, to develop a network of “key habitats”.

Practical insights to select focal species and design priority areas for conservation

Abstract The focal species approach claims that a landscape managed for the conservation of a set of focal species, each of which identified as the most threatened by specific processes, also protects all the other species. We investigated the effects of two practical issues of this approach: the problems with identifying the species most affected by threatening processes, which often only target the most area-limited species, and the disregard for the different spatial scales at which processes affect different species. We focused on a fragmented landscape in Northern Italy and selected the most area-limited (Capreolus capreolus) and dispersal-limited (Muscardinus avellanarius) mammal species. We mapped and overlapped the suitable areas for the two species considering 2 suitability scenarios. We then evaluated whether the area-limited species was more effective as a surrogate for the dispersal-limited species, or the opposite held true (a surrogate is a species able to cover at least 50% of the area and the number of patches suitable for another species). Moreover, we evaluated if buffering the suitable areas for the two species with 4 buffer sizes affected their ability as surrogates. Neither the area-limited, nor the dispersal-limited species was found to be an effective surrogate for the other species because of the very different distribution patterns of their suitable areas. Conversely, when buffers around suitable areas were designed, the dispersal-limited species acted as a surrogate for the area-limited species in 7 out of 8 cases (2 suitability scenarios per 4 buffer sizes), while the area-limited species was a surrogate in only one case. Using area-limited species as focal species may thus be detrimental and lead to conservation plans unable to protect species for which the area is not the key factor affecting the distribution pattern. Conversely, when the suitable areas are buffered, dispersal-limited species could become effective focal species.

Terrestrial mammalian fauna (Eulipotyphla, Lagomorpha, Rodentia, Carnivora, Artiodactyla) of Lozen Mountain

Field data on the terrestrial mammalian fauna (Eulipotyphla, Lagomorpha, Rodentia, Carnivora, Artiodactyla) of Lozen Мountain collected from 2005 untill 2019 were summarized. Several methods were used: live trapping, pitfall trapping, camera trapping, transects for signs (e.g. prints and scats), and visual observations. The investigation revealed relatively high species richness of the mammalian fauna in the area. The species composition of mammal associations in forested and open habitats, the conservation status and zoogeographic classification of the recorded species are presented. The distribution and habitat preferences of particular species (Neomys fodiens, Muscardinus avellanarius, Canis aureus, etc.) are discussed. The significance of the natural and the semi-natural habitats in Lozen Mountain for mammalian populations is considered. The main threats for the mammals and their habitats on the territory of Natura 2000 site “Lozenska planina” (BG0000165) are emphasized and recommendations for future management and monitoring activities are proposed.

Spatial dynamics of a hazel dormouse (Muscardinus avellanarius) population at different densities

The dynamics of socio-spatial organisation are little investigated in dormice (Gliridae), a specific group among small mammals. During 2007–2017, 668 adult individuals were captured in a hazel dormouse (Muscardinus avellanarius) population in Lithuania, with the home ranges calculated for 134 males and 62 females. Over the study period, the abundance of the population gradually declined, and it was categorised into three groups: (1) high (1.2–1.4 adults/ha), (2) medium (0.9–1.0 adults/ha) and (3) low (0.4–0.7 adults/ha). When population abundance changed from high to low, the average sizes of home ranges increased from 1.4 ± 0.6 to 2.1 ± 1.2 ha in males and from 0.8 ± 0.5 to 1.1 ± 0.4 ha in females, while the total overlap of home ranges decreased from 57 ± 28 to 35 ± 23% in males and from 77 ± 27 to 44 ± 32% in females. Home ranges of marked individuals changed in consecutive years. In males, the average displacement of the centres of the home ranges was 58 ± 21 m, 75 ± 52 m and 73 ± 39 m at high, medium and low densities, respectively. The dynamics of the spatial relations in the investigated hazel dormouse population are consistent with the general tendency of home ranges to increase when population density decreases. However, the spatial organisation of population is more stable and potentially less related to the dynamics of food resources in comparison with other forest-dwelling small mammals.

Investigating the relationship between the prey composition of Barn Owls (Tyto alba) and the habitat structure of their hunting range in the Marcal Basin (Hungary), based on pellet analysis

Abstract Little was known about the small mammal fauna of the Marcal Basin to date, therefore we collected 1,144 Barn Owl pellets from 15 locations in 2017. After the analysis of the pellets, remnants of 3,063 prey items were identified, of which 97.5% were small mammals, belonging to 21 species, while the remaining 2.5% were birds, frogs and insects. Mammal prey items consisted of Cricetidae 41%, Muridae 31% and Soricidae 28%, and in some samples, we found the remnants of European Mole (Talpa europaea), Kuhl’s Pipistrelle (Pipistrellus kuhlii), Hazel Dormouse (Muscardinus avellanarius) and Least Weasel (Mustela nivalis). Small mammal species were classified into four functional groups based on their preferences for urban, open, forest or wetland habitats. We investigated whether their relative abundances match with the proportions of the four habitat types in the assumed Barn Owl hunting ranges (cca. 2 km radius circle) in five sample sites. The relative abundance of small mammal species preferring urban habitats showed concordance with the proportion of the appropriate habitat types in the hunting area in two samples, while such concordance was proved for species favouring open, forest and wetland habitats just in one out of five samples. Small mammal functional groups represented in the prey composition do not directly correspond to the proportion of their typical habitats. We conclude that the abundance of various prey types is not suitable for characterising the landscape within the Barn Owl’s hunting range.

Changes in the tawny owl Strix aluco diet along an urbanisation gradient

The aim of this study was to describe how the diet of tawny owl changed along an urbanisation gradient. The research was conducted from 2003 to 2011 in central Poland. Pellets were collected in the following zones: the center of Warsaw, capital city of Poland (inhabited by approximately 2 million people), its outskirts and rural areas beyond the city. To investigate the differences in the percentages of the main groups of prey between the three zones, a redundancy analysis (RDA) method was implemented using CANOCO software. Sparrows, rats, pine voles and striped field mice were most connected to the city center, whereas voles (all species pooled together), northern birch mice, hazel dormice and insects were more commonly found among prey items collected in rural areas. As the outskirts were transitional areas where different habitats typical for both rural areas (such as forest complexes) and urban areas (such as parks or built-up areas) were present, no prey group was strongly connected to this landscape. Mammals were dominant in the diet in winter in all habitat types. Their share ranged from 52% (in the city center) to approximately 90% in the outskirts and rural areas. Birds, amphibians, reptiles and insects were more frequent in summer. Overall, the study confirmed high plasticity of the species as an opportunistic predator and its ability to adapt to long-term changes in its main prey in most urbanized areas.

How big is best? Various nest box sizes and their acceptance by Muscardinus avellanarius (Rodentia: Gliridae)

Abstract The hazel dormouse (Muscardinus avellanarius) can be found in nest boxes intended for birds and dormice throughout its distributional range. To minimize competition with other potential nest box inhabitants such as the edible dormouse (Glis glis) and hole-nesting passerines like the blue tit (Cyanistes caeruleus), we successfully tested nest boxes with a 21 mm entrance hole in previous studies. The only competing species still able to pass through the entrance hole were the wood mouse (Apodemus sylvaticus) and possibly the yellow-necked mouse (Apodemus flavicollis). To further optimize the nest boxes we tested whether their internal space might be important for selection by the hazel dormouse. Starting in 2015, we set up groups of four wooden nest boxes varying in base area (50×50 mm, 60×60 mm, 70×70 mm and 80×80 mm, respectively) with 21 mm entrance holes. The nest boxes were placed in an identical array at 15 stations spaced at intervals of 30 m along a hedgerow. By doing regular nest box checks and documenting all species found we investigated which nest box types were used most often by the hazel dormouse in order to detect possible preferences. So far, the data show a more intensive use of the nest boxes that provided the largest internal space, i.e. 80×80 mm.

Prevalence and seasonal variation in ticks on Muscardinus avellanarius from Germany (Rodentia: Gliridae)

Abstract We sampled ticks infesting hazel dormice (Muscardinus avellanarius) between May 2017 and September 2017 at seven locations in Germany. Of a total of 221 dormice examined, 19% were infested by ticks, but the prevalence of infestation varied strongly between sites and months. The highest prevalence at one site was noted in September (55%) while the lowest was in July (0%). In June, prevalence differed between sites from 0% to 47%. Most frequently, dormice were infested by one tick. The maximum number of ticks found on one animal was 12. All ticks were detected on the head of the animals, where the most common feeding sites were ears, nose and the area around the eyes.

What Muscardinus avellanarius like but consultants don’t: performance of nest boxes vs. nest tubes for translocations (Rodentia: Gliridae)

Abstract Nest boxes and nest tubes are widely used for surveys, for both research and development purposes, to detect and survey hazel dormice (Muscardinus avellanarius). In order to compare the performance of the two devices for translocations a study was conducted where hazel dormice had the choice between nest boxes and nest tubes. Hazel dormice preferred nest tubes over nest boxes but escaped more often from nest tubes than from nest boxes during checking. We conclude that nest boxes are the better choice for translocations as they offer the better escape ratio over nest tubes.

They don’t live forever: How life history data and encounter probability help to assess success of Muscardinus avellanarius translocations (Rodentia: Gliridae)

Abstract The hazel dormouse (Muscardinus avellanarius) is a European Protected Species and for this reason, hazel dormice are protected from deliberate killing, injury or disturbance and its sites and resting places are also protected. During development projects impacts on hazel dormouse individuals and populations should be avoided. If avoidance is not possible measures of mitigation and compensation have to be implemented. In many cases the only suitable measure to prevent disturbance, killing or injury of individuals is the translocation of hazel dormice to another suitable habitat. The success of translocations has so far been rarely documented. To assess the success of translocations, the natural mortality of hazel dormice has to be considered as well as the likelihood of finding specific individuals during the proposed action. How these data affect the assessment of translocation success is calculated based on published data on seasonal survival rates of different cohorts and of unpublished monthly encounter probabilities of a population of marked animals. Depending on the time between the translocation event and the subsequent monitoring controls the number of hazel dormice likely to be alive can be low. For this reason, success cannot be evaluated with our method if the sample size is too small.

What to eat if there are no fruits in the forest? The food of Muscardinus avellanarius in non-typical habitats (Rodentia: Gliridae)

Abstract Faeces of the hazel dormouse (Muscardinus avellanarius) were collected from two forests dominated by Norway spruce (Picea abies) and three by European beech (Fagus sylvatica) for comparison with faeces from a species-rich broad-leafed forest. Samples were analysed under the microscope. At the species-rich forest the hazel dormice consumed inflorescences, acorns from the previous year, fungi and arthropods in spring, fruits (soft mast) in summer and hard mast in the autumn. As expected, there was no, or nearly no, soft mast in the hazel dormouse diet in the beech and spruce forests. The main food sources were inflorescences, seeds, arthropods and a rather high percentage of vegetative plant material. Besides the remains of insects from eight orders, we also found spiders (Araneae), harvesters (Opiliones) and centipedes (Chilopoda) as prey of hazel dormice. Hazel dormice can feed in beech woods on beech nuts in the autumn. However, it is not yet clear how they are able to gain weight in spruce dominated forests.

Effect of imperfect detection on the estimation of niche overlap between two forest dormice

Abstract: Quantification of niche overlap represents an important topic in several aspects of ecology and conservation biology, although it could be potentially affected by imperfect detection, i.e., failure to detect a species at occupied sites. We investigate the effect of imperfect detection on niche overlap quantification in two arboreal rodents, the edible dormouse (Glis glis) and the hazel dormouse (Muscardinus avellanarius). For both species, we used Generalized Linear Mixed Models (GLMM) to estimate the occurrence probability and Occupancy Models (OM) to calculate occurrence and detection probabilities. By comparing these predictions through niche equivalency and similarity tests, we first hypothesised that methods correcting for imperfect detection (OM) provide a more reliable estimate of niche overlap than traditional presence/ absence methods (GLMM). Furthermore, we hypothesised that GLMM mainly estimate species detectability rather than actual occurrence, and that a low number of sampling replicates provokes an underestimation of species niche by GLMM. Our results highlighted that GLMM-based niche overlap yielded significant outcomes only for the equivalency test, while OM-based niche overlap reported significant outcomes for both niche equivalency and similarity tests. Moreover, GLMM occurrence probabilities and OM detectabilities were not statistically different. Lastly, GLMM predictions based on single sampling replicates were statistically different from the average occurrence probability predicted by GLMM over all replicates. We emphasized how accounting for imperfect detection can improve the statistical significance and interpretability of niche overlap estimates based on occurrence data. Under a habitat management perspective, an accurate quantification of niche overlap may provide useful information to assess the effects of different management practices on species occurrence.

Enhancing connectivity in agroecosystems: focus on the best existing corridors or on new pathways?

Restoring or establishing corridors between residual forest patches is one of the most adopted strategies for the conservation of animal populations and ecosystem processes in fragmented landscapes. This study aimed to assess whether it is more effective to focus restoration actions on existing corridors or to establish habitats in other strategic areas that can create new dispersal pathways to enhance connectivity. We considered a real agroecosystem in northern Italy, based our analyses on graph-theory and habitat availability metrics, and focused on the Hazel Dormouse as the target species. We compared the connectivity increase resulting from (i) the simulated restoration of existing priority corridors, i.e., those with significant presence of forest but in which restoration actions would still result in considerable connectivity gains, or (ii) the simulated plantation of 30 hedgerows along new priority pathways, i.e., those areas with no current forest cover in which habitat creation would be more beneficial for connectivity. Implementing new priority pathways resulted in substantially larger connectivity gains (+ 38%) than when restoration efforts were concentrated in improving already existing corridors (+ 11%). Establishing hedgerows along new pathways allowed enhancing the complementary and functionality of the full set of landscape corridors and proved more efficient than just strengthening the areas where dispersal flows were already concentrated. We demonstrated the importance of analytical procedures able to compare the effectiveness of different management strategies for enhancing connectivity. Our approach may be applied to multiple species sensitive to fragmentation in other heterogeneous landscapes and geographical contexts.

The significance of major roads as barriers and their roadside habitats as potential corridors for hazel dormouse migration – a population genetic study

Major roads are commonly regarded as migration barriers for most terrestrial animal species. Hazel dormouse, Muscardinus avellanarius, populations in south-eastern Schleswig-Holstein were investigated in order to assess the possible effects of major roads on their genetic variability and genetic structure. A total of 177 samples were collected and analysed, using ten microsatellite loci. Estimates of genetic diversity (expected heterozygosity: 0.48-0.65, allelic richness: 2.9-3.9) were within the range commonly found in this species. No evidence of inbreeding or past bottlenecks was detected. The software structure grouped the samples into five subpopulations. However, this subdivision should be treated with caution, since many individuals with mixed or unclear genetic profiles were found, possibly representing migrants or their offspring. Contrary to the previous assumption that dormice hardly ever cross roads, the present study shows that dormice not only cross even major roads, but also hold close relationships to individuals living on the other side of the motorway. The high number of animals captured within a small area and the relatively low genetic differentiation (FST: 0.142 and 0.105) despite the great distances (33.1 and 25.6 km) along the road, indicate that the roadside shrubs can actually be good habitats for dormice and provide suitable corridors for migration.

The different effects of periodic experimental tree removal patterns on the population demography of the hazel dormice (Muscardinus avellanarius) in a conifer plantation

Within a conifer plantation, hazel dormice (Muscardinus avellanarius) were individually marked from 2000 to 2016. In four adjacent experimental study areas (ESAs) of 3 ha each, a different method of restoration of a Planted Ancient Woodland Site (PAWS) was carried out in autumn 2003 to remove ca. 33 % of conifers. A third of those left were removed in 2009 and in 2015. The effects on dormouse abundance indices were recorded by routine monitoring of nest boxes, including marking individuals. The overall number of dormouse captures varied from year to year, increasing the year following forestry operations in 2003 and 2009, possibly because nest boxes temporarily became more attractive. The numbers of individually marked adults showed a stable trend but less variation. The numbers of small juveniles recorded appears to be rising in recent years, suggesting a positive impact during the later stages of this conifer forest reversion. The overwinter survival index of marked juveniles fell significantly for those born the year after each forest operation but not those alive when the felling took place. Adult survival did not fall in either year. Initially, dormouse populations were sustained in each ESA after management and the numbers were not significantly different between the treatments. After the 2009 operation dormouse numbers fell significantly in the traditional mechanical area-wide forest thinning treatment and low abundance has continued. This study demonstrating maintenance of a population of a European Protected Species has important implications for managers and we suggest similar forest management considerations are incorporated into policy and best practice guidelines. The results so far suggest that a patchwork regime type of conifer removal regime can be chosen to be both pragmatic for an economic forestry business and ensuring dormice remain in the local forest.

Habitat preferences of hazel dormice Muscardinus avellanarius and the effects of tree-felling on their movement

Modern management of multifunctional woodlands must address many and various demands, including for recreation, timber production and the conservation of biodiversity. The responses of individuals and populations of protected species to woodland management and habitat change are often not well understood. Using radio-tracking and LiDAR, we investigated the short-term habitat preferences of hazel dormice Muscardinus avellanarius, and their ranging and resting behaviours before and after small-scale tree felling, following a before-after control-impact design. Mean dormouse home range size was 0.51 Ha (±0.07 SE, n = 16) and did not vary between sexes or among sites, though heavier animals had smaller ranges. Dormice preferred mid-height woodland habitat (5–10 m tall), with low proportions of high forest (over 10 m tall), for both ranging and resting sites. Ranging habitats were often located on woodland edges and relatively dense vegetation. Dormice preferentially used yew, rowan and hazel during ranging. There was no difference in the distances travelled by dormice before and after felling, but dormice in areas where trees had been felled showed less evidence of a shift in ranging area than those in unfelled areas. Although the limited response of dormice to tree felling activities has the potential to be associated with increased mortality and/or limited dispersal of individual dormice, the requirements of dormice for mid-successional and edge habitats that arise after tree removal means that a dynamic optimum of felling and regeneration is essential for conservation of dormouse populations.

Climate, landscape, habitat, and woodland management associations with hazel dormouse Muscardinus avellanarius population status

Abstract Although strictly protected, populations of the hazel dormouse Muscardinus avellanarius in the UK declined by 72% from 1993 to 2014. Using National Dormouse Monitoring Programme data from 300 sites throughout England and Wales, we investigated variation in hazel dormouse population status (expressed as Indices of Abundance, Breeding, and population Trend) in relation to climate, landscape, habitat, and woodland management. Dormice were more abundant and produced more litters on sites with warmer, sunnier springs, summers, and autumns. Dormouse abundance was also higher on sites with consistently cold local climate in winter. Habitat connectivity, woodland species composition, and active site management were all correlated with greater dormouse abundance and breeding. Abundances were also higher on sites with successional habitats, whereas the abundance of early successional bramble Rubus fruticosus habitat, woodland area, and landscape connectivity were important for population stability. Diversity in the structure of woodlands in Europe has decreased over the last 100 years, and the habitats we found to be associated with more favourable dormouse status have also been in decline. The conservation status of the hazel dormouse, and that of woodland birds and butterflies, may benefit from reinstatement or increased frequency of management practices, such as coppicing and glade management, that maintain successional and diverse habitats within woodland.

Dormouse (Gliridae) status in Lithuania and surrounding countries: a review

Lithuania and surrounding countries are situated in the northern part of dormouse (Gliridae) distribution ranges. Garden dormouse may be extinct in all these countries because the last observations of this species were recorded in the end of 20th century. Fat dormouse is rare and declining in Lithuania and surrounding countries because of destruction of their habitats – felling of mature oakdominated forests. Forest dormouse is rare because western limit of is distribution range goes through Latvia, Lithuania and Poland. Status of the hazel dormouse is different in the countries concerned. This species is common and widespread in Lithuania, but red-listed in Latvia and Belarus, and absent in large deforested areas in Poland. The hazel dormouse may be extinct in Estonia, but common and not threatened in southern Sweden. In different countries, status of the hazel dormouse depends on anthropogenic influence on its habitats and probably also on investigation level. Some outdated information on distribution and status of some dormouse species is presented in the IUCN red lists.

New records for Anaplasma phagocytophilum infection in small mammal species

BackgroundTick-borne diseases pose a major threat in public health. The epidemiological dynamics of these diseases depends on the tick vector species and their hosts, as well as the geographical distribution and ecology of both. Among many possible hosts for ticks, small mammals have a major role in the development of immature stages of several tick species. Small mammals are also important reservoir hosts for several pathogenic agents and possible reservoirs for Anaplasma phagocytophilum. In this context, the aim of our study was to evaluate the prevalence of A. phagocytophilum in small mammal species in Romania.ResultsA total of 791 small mammals of 31 species were tested by PCR, targeting the rrs gene for detection of A. phagocytophilum DNA. Positive results were obtained in 20 small mammals: five Apodemus flavicollis (6.49%), three Sorex araneus (9.09%), three A. uralensis (4.84%), two A. sylvaticus (3.92%), and one of each Spermophilus cittelus (7.14%), Microtus agrestis (3.85%), Sorex minutus (3.85%), Muscardinus avellanarius (3.13%), Crocidura suaveolens (2.44%), Mus spicilegus (2%) and M. arvalis (1.75%).ConclusionsEleven small mammal species were found to be carriers of A. phagocytophilum, suggesting a possible involvement of these species in its epidemiology. To our knowledge, this is the first report of A. phagocytophilum in S. minutus, C. suaveolens, M. spicilegus, M. avellanarius and S. citellus.