IVth International Conference on Dormice (Rodentia, Gliridae)

Tester, R.

Nasenweg 14, 4052 Basel Switzerland, e-mail: oeskop@oeskop

All four Middleeuropean dormice species actually occur in the Unterengadin (Grison, Switzerland). They were recorded by a new indirect method, which was only experienced on common dormice so far. The garden dormouse is the most frequent dormouse in the Unterengadin. It inhabits most of the different biotopes, having some structures close to the ground, prefers a good cover with needle-, leaf- or grass litter, branches and/or stonecaves as much as possible.

The fat dormouse on contrary inhabits only the lowest part of the valley up to Sent and its maximum altitude of occurence is 1430m o.s. Fat dormouse needs hazelbushes in his habitat. Fat dormouse and garden dormouse have different demands on their habitats. There was no evidence of interspecific competition for these demands. But in some hazelbushes around Scuol, as potentional habitat for the fat dormouse, only garden dormice could be recorded. Though interspecific competition is possible but another minimum factor than habitat requirements is exspected.

After just hundred years we could record common dormouse in the Unterengadin again in a new site at 1430m o.s. There they live together with garden dormouse and fat dormouse in the same habitat. During this century forest dormice have been recorded at six different sites in the Unterengadin. Unfortunately and in spite of intensive searching, we could not find new forest dormouse sites and only one site has been confirmed. The forest dormouse is expected to disappear in the Unterengadin.>From different coexistence recordings, literature and oral information we conclude that all four species nhabit their own ecological niche in relation to their habitat requirements. It is not clear whether interspecific competition or habitat requirements or both, are the reason why garden dormouse and forest dormouse do not coexist in the same habitat.

Before Abstracts