Harvest Mouse Micromys Minutus Research Articles

Every branch in its niche: intraspecific variation in habitat suitability of a widely distributed small mammal, the harvest mouse Micromys minutus

Climate and land use changes re-shape the distribution of species around the world, so understanding biogeographical patterns is key to protect and manage wildlife, particularly in the case of threatened or declining species. Species with wide ranges are usually considered as common, yet the occurrence of intraspecific variability and adaptation to local conditions may pose serious challenges to their conservation. In this paper, we selected the harvest mouse Micromys minutus as a model species to assess the role of intraspecific genetic variability in shaping the environmental preferences and distribution of a widely distributed mammal across Europe. By applying an integrative approach combining species distribution modelling and phylogenetic reconstruction, we assessed the clade-specific habitat suitability of all mitochondrial clades of the species occurring in Europe, unveiling distinct bioclimatic niches. Most of Central Europe results as suitable to M. minutus, whereas different clades showed distinct distributions of suitable areas across Europe, with limited overlap. We then combined mitochondrial analyses with clade-specific suitability maps to determine the geographic delimitations of Italian and central European clades. We showed that individuals from the northernmost Italian regions actually belong to the central European clade, consistent with the biogeographical patterns of other small mammals, and indicating potential past dispersal between the Italian Peninsula and Central Europe, or human-assisted translocations. Our results highlight the importance of intraspecific variability in shaping biogeographical patterns of widely distributed species, also representing a reproducible exercise to understand their environmental preferences and eventually fostering their conservation.

Harvest mouse Micromys minutus of the Urals and Western Siberia: range boundaries and genetic diversity

Harvest mouse Micromys minutus of the Urals and Western Siberia: range boundaries and genetic diversity

Unveiling the Genetic Diversity of Declining Population of the Harvest Mouse Micromys minutus in Italy

The Italian peninsula represented one of the main glacial refugia during climatic oscillations of the Pleistocene, currently being a biodiversity hotspot. In this work, we analysed for the first time the genetic diversity of harvest mouse populations in Italy, and we compared them with those of the rest of Eurasia. Mitochondrial cytochrome-b gene was amplified from 12 samples from throughout the Italian range. We recorded a very low genetic diversity, in line with the rest of the harvest mouse range. In the comparative phylogenetic tree, Northern Italy samples clustered together as a sister group of the rest of Europe, whereas those from Central Italy clustered with Central Europe samples. Harvest mice have recently conquered Southern Europe, i.e., possibly at the start of the Holocene. The global genetic homogeneity might be due to accidental human-mediated introductions or to the sharp decline of the habitat of the harvest mouse, which may in turn have caused severe bottlenecks in the populations of this small rodent.

Население мелких млекопитающих подтайги Южного Зауралья

On the basis of materials obtained using two generally accepted counting methods, data on the species composition of small mammals, the ratio of background and dominant species, the total abundance in the main groups of biotopes of the South Trans-Ural region are presented. The differences in the community structure of small mammals in the subtaiga and forest-steppe sub-zone of the South Trans-Ural region have been analysed. The paper discusses materials on the community of small mammals in the sub-taiga of the South Trans-Ural region. A brief history of the study of this group of animals is reviewed. The use of two counting methods (the ditch with pitfalls and trap-lines) allowed the most complete identification of the species composition of insectivores and rodents in the sub-taiga of the South Trans-Ural region in 2021. In terms of species, the ditch with pitfalls were more effective, with 17 species identified; trap-lines counted 13 species. The abundance of animals in 2021 was very low. In our opinion, was determined by the abnormally hot spring and summer period. On average, only rare and very rare species have been recorded in the snap-trap counts in the study area. Numerous species were absent in the average meaning regardless of the method of capture. The core of small mammals of the sub-taiga of the South Trans-Ural region consisted of species typical of humid habitats and small-leaved forests, such as the Laxmann's shrew Sorex caecutiens, common shrew S. araneus and Eurasian pygmy shrew S. minutus rodents, as well as the common vole Microtus arvalis and harvest mouse Micromys minutus (surveys using the ditch with pitfalls). The common shrew was predominant in the snap-trap counts, accounting for about 45% of the total abundance of all animals recorded. In pine forests with poor productivity and in open spaces, the total abundance of insectivores and rodents is lowest. The species composition of small mammals of the sub-taiga and forest-steppe subzone of the South Trans-Ural region are largely similar (83% of the total species). Specific features of the taiga subzone were determined by the taiga shrew Sorex isodon and Siberian chipmunk Eutamias sibiricus, unusual for the forest-steppe and herb-bunchgrass steppe subzone of the South Trans-Ural region. A characteristic feature of the sub-taiga of the South Trans-Ural region is a specific proportion of the northern red-backed vole Myodes rutilus and European bank vole M. glareolus, their abundance is comparable, or the M. glareolus predominates, which is not observed in the forest-steppe. In the sub-taiga, in the surveys using ditch with pitfalls among insectivores and rodents, the Laxmann's shrew prevailed, its share was approximately one fourth of all recorded animals, although in general the community of small mammals is polydominant, in contrast to the surveys using the trap-line method, where one species dominated – the common shrew. In 2021 (sub-taiga) as well as in 2020 (forest-steppe) the territory of the South TransUral region was characterized by a deep depression of water vole Arvicola amphibius numbers, which was completely absent in the counts.

Autumn habitat selection of the harvest mouse (Micromys minutus Pallas, 1771) in a rural and fragmented landscape

The harvest mouse Micromys minutus has, through nest findings, been documented to live in wetlands in tall sedges and grasses in Central Europe. However, there is very little information on the type of habitat this species uses outside of nesting, because this rodent is difficult to capture in ordinary trapping set-ups. In France and Switzerland, the harvest mouse populations have decreased strongly in the past two centuries due to the drastic reduction of its favored habitat. The present study used radiotracking to examine a small population in Eastern France living in a fragmented rural landscape. The aim was to learn more about the habitat and vegetation selection of this population during autumn. The results showed that the most favored habitats were in patches of stinging nettles (Urtica dioica) and American goldenrod (Solidago gigantea) rather than in their supposedly preferred vegetation type, which are tall grass wetlands. The results also presented migrating behavior in three out of the eight monitored individuals, which lead to the discovery of a possible wintering area in an unmown grassy site around a plant dump. These results suggest that disturbed, but unmown areas are important for the harvest mouse as wintering vegetation and should be available in the surrounding of a reproduction site. The results also showed that wetland management must take into account the affinity of this mammal for areas invaded by American goldenrod, in order to prevent the harvest mouse populations from decreasing in those secondary habitats. (Less)

Laelapidae mites (Acari: Mesostigmata) infesting small rodents in the Curonian Spit, Lithuania

Laelapidae (Acari, Mesostigmata) mites are ecologically diverse and involve predators and parasites found in various habitats. In the present study, Laelapidae mites were collected from 236 small rodents of five species (the yellow-necked mouse Apodemus flavicollis, the harvest mouse Micromys minutus, the bank vole Myodes glareolus, the root vole Microtus oeconomus, and the field vole Microtus agrestis) in the Curonian Spit in 2013–2014. Five species of Laelapidae mites – Laelaps agilis, Hyperlaelaps microti, Haemogamassus nidi, Eulaelaps stabularis and Myonyssus gigas – were identified based on the morphological characters of adult females and males. The present study is the first detection of Laelapidae mites parasitizing small rodents in the Curonian Spit, Lithuania.

Description and phylogenetic affinities of two new species of Nomadolepis (Eucestoda, Hymenolepididae) from Eastern Palearctic

Two new species of hymenolepidid cestodes belonging to the genus Nomadolepis are described from small mammals in western Siberia and the Far East, Russian Federation. Nomadolepis fareasta n. sp. is described from the striped dwarf hamster Cricetulus barabensis in Amurskaya Oblast' and Nomadolepis shiloi n. sp. is described from the Eurasian harvest mouse Micromys minutus from Novosibirskaya Oblast' and Amurskaya Oblast'. Nomadolepis fareasta n. sp. differs from Nomadolepis merionis, Nomadolepis ellobii and N. shiloi n. sp. in having a substantially longer strobila, longer cirrus-sac and wider ovary. Furthermore, N. fareasta n. sp. can be readily distinguished from its congeners by the arrangement of the testes and the number and size of rostellar hooks. Nomadolepis shiloi n. sp. differs from N. merionis, N. ellobii and N. fareasta n. sp. by the number and length of the rostellar hooks, the presence of irregular transverse anastomoses as well as the length of the cirrus-sac and position of the cirrus-sac in relation to the poral ventral osmoregulatory canal. Morphological differentiation of the two new species from morphologically similar Palearctic species of the related genus Rodentolepis (sensu lato) from rodents is also provided. Phylogenetic affinities of Nomadolepis were studied for the first time using partial sequences of the nuclear ribosomal 28S DNA gene. Phylogenetic analysis strongly supported the status of Nomadolepis as a separate genus closest to Pararodentolepis.

Live trapping design for the harvest mouse (Micromys minutus) in its summer habitat

The harvest mouse Micromys minutus is a very rare species in Switzerland. It has only been documented accurately since 1960. Most records are based on nest findings and there have been few direct observations or captures, mainly because live trapping of this species is not simple. Therefore, an efficient trapping technique is needed for population studies and to facilitate the management of its habitat. By combining the methods used to capture very small (Suncus etruscus) and climbing (Muscardinus avellanarius) mammals, we developed a design using Longworth traps with mouse excluders set on suspended platforms. This allowed us to trap more harvest mice in four field sessions of 60 trap-nights than have ever been caught previously since its discovery in Switzerland.

Overwintering in nests on the ground in the harvest mouse

The harvest mouse Micromys minutus has adapted to inhabit the stalk zone of grassland vegetation and is identified by the characteristic nests this species builds on grasses above the ground. Such aerial nests have been considered as an almost exclusive sign of harvest mouse populations and have therefore also been used to determine habitat choice and population density of the harvest mouse. However, we found that nests built on the ground occur after farmers burn away grasslands dominated by native grass Miscanthus sinensis and Pleioblastus chino. The aim of this study was to determine whether the harvest mouse habitually builds this type of nest and, if so, when it occurs. Because it was difficult to locate nests on the ground when the soil was covered with grasses, we located all the nests in the native grasslands after burning in the spring in 2 consecutive years. We then attempted to estimate nesting time by comparing the mineral content of nest materials to mineral dynamics in M. sinensis leaves. Nests were distributed over all the grasslands investigated, and nesting times were calculated to occur between early September and middle March. Our findings demonstrate the harvest mouse repeatedly constructs this type of nest for overwintering. Considerable nondetection errors would have occurred with regard to this species by exclusively interpreting data on the presence or absence of aerial nests.

On the taxonomic status of the harvest mouse Micromys minutus (Rodentia: Muridae) from Vietnam

The taxonomic status of the harvest mouse Micromys minutus from Vietnam is re-evaluated. The mtDNA analysis shows that the harvest mice from Lao Cai Province of northern Vietnam belongs to a distinct phylogenetic lineage, previously known only from a haplotype from Chengdu, Sichuan Province, southern China (Yasuda et al. 2005). The mtDNA analysis shows a strong genetic divergence among this lineage and all the other known haplotypes of Micromys minutus (11.68% for cytochrome b gene sequences). Canonical discriminant analysis of cranial and dental data, as well as of some external characters, also separate the Vietnam – South China group (also including an Indian specimen) from other Palaearctic populations. The skull of southern populations is relatively large, with a longer and broader palatine. The dorsal pelage of the Vietnamese specimens is grey, tinged with brown in comparison with the red-brown dorsal colouration sharply contrasting with the white underside in the majority of Euro-Siberian adults. The harvest mice of the Vietnam – South China group are distinguished from the typical European ones by their rather long tail that is about 120% of the body length (82 to 95% in the Palaearctic populations). Both genetic and morphological data suggest the existence of a second Micromys species, occurring at least in North Vietnam and South China. The available name for this species is Micromys erythrotis (Blyth, 1856).

A suitable embankment mowing strategy for habitat conservation of the harvest mouse

The harvest mouse Micromys minutus (Pallas 1771), a small rodent, builds its nests on tall grasses such as Amur silvergrass Miscanthus sacchariflorus (Maxim.) Benth. This mouse species is endangered by grassland habitat loss worldwide. Although embankments are one of the mouse’s nest sites in Japan, these habitats are not stable because of regular mowing. To investigate ways of increasing the habitat suitability of embankments, research was carried out over a 2-year period in western Japan on an embankment where Amur silvergrass was dominant. Two to three divisions of the embankment were mowed at intervals in spring and autumn, and seasonal changes in nesting and vegetation were examined. Nest sites were evaluated using Manly’s index. In each year, the nesting period was extended and more nests were built compared to past years when phased mowing was not performed. The density of nests in each division increased in order of mowing in spring, but was low in autumn. Amur silvergrass was the preferred nesting plant and other perennial grasses were avoided. Annual grasses were preferred over Amur silvergrass in 2005. Nesting restarted when Amur silvergrass recovered to heights of >100 cm in all divisions, regardless of the mowing month. Each year, 120–160-cm-tall Amur silvergrass was preferred, while plants <80 cm high were avoided. Phased mowing, which allows annual grasses and Amur silvergrass sufficient time to recover, is clearly an effective method of maintaining stable nesting habitat for the harvest mouse on an embankment.

Nest-site selection by the harvest mouseMicromys minutus in seasonally changing environments

We studied nest-site selection of harvest miceMicromys minutus (Pallas, 1771) for clarifying plant community characters suitable for nesting. We surveyed newly constructed nests in a marsh population and various plant characters likely to affect nest-site selection throughout the breeding season. The harvest mouce used common reedMiscanthus sacchariflorus and Japanese pampas grassMiscanthus sinensis more frequently than expected by the propotions of their areas occupied in summer, but shifted toCarex confertiflora after October. Although reed grassPhragmites communis was dominant in the marsh, mice did not choose this species. The 2 grass species selected in summer had a larger number of leaves per unit area, and the most selected species had a higher stem density. Both of these plant traits indicate a richness of nesting materials. The rapid increase in selection forCarex from autumn to winter was likely due to its leaf freshness and/or flexibility, as leaves ofCarex maintained a high level of chlorophyll content until winter. The harvest mouse appeared to flexibly change its selection for nesting plants in response to seasonal environmental changes. We also discuss the implications of our findings in terms of harvest mouse habitat conservation.

Habitat characteristics of harvest mouse nests on arable farmland

The suitability of both arable field margins and beetle banks as nesting habitat for the harvest mouse Micromys minutus was investigated. The proportion of robust stemmed herbaceous plants and grasses at nest sites in beetle banks was greater relative to the comparison sites. The main nest supporting species in field margins were bramble Rubus fruticosus and thorns Crataegus monogyna and Prunus spinosa. Nests were constructed where the vertical structure of the vegetation was significantly denser than average. Nest density was greater in the beetle banks than in field margins. The creation of beetle banks and grassy field margins on arable farmland clearly provided suitable nesting sites for harvest mice. The current management practices seemed to provide the structural vegetation necessary for nesting harvest mice.

Small mammals in new farm woodlands

ABSTRACTA number of recently planted farm woodlands, along with adjacent agricultural land and hedgerows were surveyed using live traps to compare their importance for small mammals. Small mammal numbers were far higher in newly planted woodlands than in both hedgerows and agricultural land. Seven species were trapped in farm woods compared with five in hedgerows and two in agricultural land. The most frequently trapped species in the establishing woodlands was the harvest mouse Micromys minutus, followed by the wood mouse Apodemus sylvaticus. The potential importance of newly planted farm woodlands for small mammals is discussed.