IVth International Conference on Dormice (Rodentia, Gliridae)13 - 16 September 1999 EDÝRNE - TURKEY |
THE ECOLOGY OF THE GARDEN DORMOUSE (ELIOMYS QUERCINUS) IN THE ALPINE HABITAT
Bertolino, S. & Currado, I.
Di.Va.P.R.A. Entomology and Zoology, University of Turin, I-10095 Grugliasco (TO), Italy, e-mail: mmkbe@tin.it
The garden dormouse (Eliomys quercinus) has a widespread distribution in the Palaeartic Region, where it colonizes different habitats and can inhabit coniferous and mixed forest as well as hilly and cultivated land. The ecological flexibility of this species enables it to live from the sea level in the Mediterranean area up to 2000 m a.s.l. in the Alps.
In order to study the ecological adaptation of the garden dormouse to the alpine habitat, we carried out a three years study by means of the CMR method. Furthermore, we analized all the data available from the local Mammals Atlas project and from other studies conducted in the Western Italian Alps and regarding the distribution and habitat selection of small mammals.
In the Western Italian Alps the garden dormouse inhabits mainly coniferous woodlands while it seems rare or absent in deciduous forests. On the other hand, the fat dormouse (Myoxus glis) is present in deciduous woodlands and generally absent from coniferous forests. Thus, our data suggest an ecological segregation between the two species, with the fat dormouse located in low height woods and the garden dormouse inhabiting alpine woodland.
The severe weather condition of the alpine areas resctricts the activity season of the garden dormouse to five months: from May to September. This short period allows only one yearly reproduction. Reproductive females suffer a weight loss associated with delivery and lactation and, in spite of their high growth rate in August, they need to be active for more time in September. In years with bad weather condition in September, the cost of reproduction could involve a higher mortality rate in females.
The life history of 21 adults captured repeatedly times in the activity season, enables us to evaluate the incidence of predation on the population that we studied. Only three animals (14.3%) disappeared from the area before September, the month in which we assume the animals enter hibernation. Their loss could be due to predation, but also to a shift in their home range or a mortality related to other causes. On the other hand winter mortality was high, and ranged between 50 and 64%.
In conclusion, the garden dormouse inhabits only coniferous woodlands in the Western Italian Alps. The population dinamics in these alpine habitats seems to be conditioned by winter survival, while predation seems not a limiting factor.