Giulia Sozio

Population and individual-scale responses to patch size, isolation and quality in the hazel dormouse

This study was funded by: WWF ‘‘Biodiversamente’’ and ‘‘Brusarosco’’ grants to A. Mortelliti. Further funding was provided by Riserva Naturale Selva del Lamone, University of Rome ‘‘La Sapienza’’, private funds.

Empirical evaluation of the strength of interspecific competition in shaping small mammal communities in fragmented landscapes

ContextTheory predicts that habitat loss and fragmentation may have drastic consequences on species’ interactions. To date, however, little empirical evidence exists on the strength of interspecific competition in shaping animal communities in fragmented landscapes.ObjectivesOur aim was to measure the degree of ongoing competitive interference between species in fragmented landscapes. Our model system was the community of ground-dwelling rodents in deciduous woodlands in central Italy, composed of a habitat generalist species (Apodemus sylvaticus) and two forest specialists (Apodemus flavicollis and Myodes glareolus). Our objectives were to test whether species were segregated among forest patches and whether spatial segregation was determined by interspecific competition or habitat and resource availability.MethodsWe surveyed the populations inhabiting 29 woodland patches in a highly fragmented landscape using a capture-mark-recapture protocol, capturing >4500 individuals. First we modelled species’ distribution as a function of habitat, resource availability and landscape variables. The second stage of our analyses involved measuring the response of vital rate parameters (body mass, reproduction, survival, recruitment, population density) to competitor density.ResultsThe relative distribution of species reflected a spatial segregation of habitat generalists and specialists according to habitat quality, cover and connectivity. Interspecific competition mainly affected individual level vital rates, whereas we found no substantial effects at the population level.ConclusionsCompetitive exclusion of specialist species by generalist species was occurring. However, when compared to other factors such as habitat connectivity and resource availability, interspecific competition played a relatively minor role in shaping the studied community.

Field identification of Apodemus flavicollis and Apodemus sylvaticus: a quantitative comparison of different biometric measurements

Abstract The identification of the wood mouse Apodemus sylvaticus and the yellow-necked mouse Apodemus flavicollis in the field has challenged many generations of field mammalogists, particularly in northern Spain and continental Italy. These two species present highly similar morphologic and morphometric characteristics especially when they are sympatric. Existing identification methods rely on morphometric and biometric measurements collected on killed or etherized animals, whereas in many field studies measurement may be taken only on live and awake animals. Genetic methods, instead, are time consuming, expensive and do not allow immediate identification in the field, which is a requirement in many types of ecological works. To contribute in filling this knowledge gap, the aims of this research were: 1) to assess biometric measurements (weight and length of hind foot) that allow species identification on live and awake animals and 2) to develop a predictive model and related software that, subject to refinement based on study area, will allow researchers to prioritise the selection of individuals to be identified by molecular approach. This model, based on a large (>1500) sample of individuals captured in two different sites in central Italy, should help to classify live and awake individuals of Apodemus species. Attached to this paper is a Microsoft Excel spreadsheet that may be used to apply the model to new data.

Ultrasonic communication in Gliridae (Rodentia): the hazel dormouse (Muscardinus avellanarius) as a case study

Ultrasonic vocalizations (USVs) have been detected in a range of small mammals, particularly rodents, and are associated not only with different social behaviours, e.g. sexual behaviour and aggression, but also with non-social behaviour in several species of mammals, including echolocation and as a by-product of respiration. Rodents in the Gliridae family are known to broadcast a variety of signals, but the behavioural relevance of the latter is poorly known. The aim of our study was to describe the vocal signals of Muscardinus avellanarius and to assess their function. By recording vocal and non-vocal behaviour of captive individuals in different social contexts, we demonstrate that M. avellanarius emits USVs and provide contextual evidence that such sounds are largely used for social communication. We identified six different vocalizations with an overall frequency range between 6.5 and 52.1 kHz, five out of six being ultrasonic (>18 kHz). The vocal repertoire in M. avellanarius was associated with social behaviours, e.g. mother–infant reunion, isolation and paired opposite-sex courtship, all activities involving individuals that are out of mutual visual contact. We therefore infer that this repertoire constitutes a medium-distance (in the range of a few metres) communication system. Further research testing different social contexts both in nature and in captivity is needed for a more complete assessment of the vocal repertoire of this species and its function.

Multiple broods from a single mating in the hazel dormouse ( Muscardinus avellanarius )

Abstract Sperm retention and delayed implantation are reproductive adaptations, which allow animals to optimize timing of birth and increase individual breeding potential. Such mechanisms are widespread in the animal kingdom. However, among rodent mammals, these mechanisms are only known for murids. In this work, we report the first documented case of multiple broods in a row in a glirid rodent, the Hazel Dormouse. We recorded the production of two litters by the same adult captive female after a single mating session with a male. We discuss the relevance of our findings towards a better understanding of the dormouse’s reproductive biology and its conservation. Future research should clarify the exact mechanisms underlying this phenomenon and establish its frequency in wild populations of this species.