SPATIAL MOVEMENT PATTERNS IN FROGS - DIFFERENCES BETWEEN 3 RANA SPECIES

Using drift fences, the spatial movement patterns of the pool frog (Ra na lessonae Camerano), the moor frog (R arvalis Nilsson) and the commo n frog (R, temporaria L.)were studied with respect to orientation and vegetation at two common breeding pond at 60 degrees N in Sweden. Obse rved captures of the respective species were tested against (i) captur es expected from random movements and (ii) each other; this was done s eparately for three time periods, each of tv;a study years. The moveme nt patterns differed consistently in terms of orientation. In the adul ts, movements of the pool frog were oriented towards/from other pool f rog localities and adjacent marshes, while those of the common fro:: w ere random. The moor frog exhibited an intennediate pattern with occas ional deviations from random movements. In the juveniles, movements of the pool frog were target-oriented as in the adults, while those of t he common frog were consistently oriented towards/from forest habitat. Again, the moor frog exhibited an intermediate pattern, moving toward s adjacent marshes. The target-oriented movements ore highly correlate d with the life-history features of the species and probably occur by means of navigation mechanisms similar to those described from homing studies.