Variations in anuran movements and habitat use: Implications for conservation

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Anurans (frogs and toads) have suffered recent notable declines, and many species for long-term conservation may need protection from environmental disturbances. Protective measures depend on conserving areas actually used, and habitat use by anurans is poorly known. A total of 68 studies covering 50 species provided information used in this review. Eighteen studies (15 species) documenting post-breeding movement distances found frogs remained at their breeding site year-round, six studies (five species) recorded movements to new riparian areas and 33 studies (24 species) found frogs used separate terrestrial post-breeding sites. Mean movements to new riparian sites ranged from 38 to 700 m and terrestrial sites from 385 to 1810 m. With values varying greatly, movement for an average species was difficult to predict. Individual movement within studies also varied widely, resulting in wide scatter of study populations. When separate non-breeding sites were used, bufonid populations (range 30-800 m; n = 9) appeared to move further than hylids (35-594 m; n = 9). Maximum distances followed similar patterns. Body size was not a significant predictor of overall movement distance, but this was significantly greater in bufonids as adult size increased. Values were not apparently affected by breeding habit or study method. Frogs often overwintered at their post-breeding activity site (16 studies), but in 10 studies, at least some frogs moved to distinct and often protective overwintering areas. Mean home range was from 6.3 to 5099 m2 (mean 1773 m2; n = 18), and was not significantlyinfluenced by body size. Bufonids' habits wererelatively consistent, whereas these were more diverse in ranids and hylids. The wide scatter of data indicated that protective measures applied are uncertain to protect all or even most of a target population; detailed biological studies remain important to ensure conservation of populations.