Post-breeding migrations of newts (Triturus cristatus and T. marmoratus) with contrasting ecological requirements

Two newt species with contrasting ecological requirements (Triturus cristat us and T. marmoratus) were radio-tracked after leaving a shared breeding po nd in western France. Movements of 30 individuals were recorded over 491 da ys. During the first terrestrial night, the newts migrated with high direct ionality up to 137 m to their refuges. Burrows of small mammals were among the favourite refuges. Movements after the first night were mostly undergro und and over shorter distances (< 6.8 m). Sixty-four per cent of all tracke d newts stayed within 20 m of the pond edge, and migrations were recorded u p to 146 m away from the pond. Both species preferred areas with bushes, he dgerows and trees, and avoided pastures and open areas. Migration in the di rection of a habitat type characterized by trees and underground shelters w as favoured over migrations in other directions. A clear terrestrial niche separation between the two newt species was not observed. The results are d iscussed in relation to previous findings that T, cristatus supersedes T. m armoratus as a consequence of anthropogenic change to the terrestrial envir onment, affecting the species differentially.