A. Ponsero et P. Joly, CLUTCH SIZE, EGG SURVIVAL AND MIGRATION DISTANCE IN THE AGILE FROG (RANA-DALMATINA) IN A FLOODPLAIN, Archiv fur Hydrobiologie, 142(3), 1998, pp. 343-352
In animals with complex life cycles, the cost of migration among habit
ats has to be balanced by optimization of growth and survival within e
ach Life-stage habitat. In this context, migration distance is expecte
d to depend on local density and movement potential. In ectotherm spec
ies, because movement potential is related to body size, larger indivi
duals are expected to cover longer distances than smaller individuals
thus avoiding competition. This hypothesis was investigated in the agi
le frog (Rana dalmatina). For breeding, this species migrates from und
ergrowth towards ponds located in open environments. Most egg batches
were found in sites located 50-100 m from the forest edge. Batches fro
m larger frogs were more numerous at greater distances, as far as 300
m from the forest edge thus confirming the hypothesis. These results m
ust be taken into account for the conservation of this endangered spec
ies.