2005, pp 151-203

Migration in amphibians and reptiles: An overview of patterns and orientation mechanisms in relation to life history strategies

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Abstract

Differences in integumentary permeability dictate alternative life history strategies in amphibians and reptiles. Limiting resources for amphibians are chiefly associated with availability of water and, as a consequence, amphibian migrations are chiefly associated with movements to and from aquatic breeding habitats. These cyclic migrations from breeding to overwintering sites may be direct, or may be interrupted by periods of residence at foraging sites. In general, migrations take place over relatively short distances and are constrained by the problem of water balance associated with exposure during longer overland journeys. Many amphibians exhibit complex mechanisms of orientation involving multiple sensory modalities and are capable of precise homing abilities.

Among reptiles, migrations are chiefly associated with travel to and from egg laying sites, as displayed by turtles, or communal hibernacula, as is characteristic of some snakes. Marine turtles, in particular, undertake long distance migrations (up to thousands of kilometers) to reach nesting beaches and, sometimes, foraging grounds. In these chelonians, complex patterns of movement vary ontogenetically, as well as by gender and species. A variety of cues are used to locate destinations, including celestial, geomagnetic, olfactory, auditory, thermal, wave, and current pattern signals; however, evidence of a map-compass system of navigation is equivocal.

The migratory patterns of amphibians and reptiles often bring them into conflict with human resource utilization. For amphibians, breeding migrations that cross busy roads or areas turned over to agricultural production lead to mass mortality. Marine turtle migratory pathways often result in conflicts with fishery activities. Knowledge of life history strategies and associated migratory behavior is essential for effective conservation measures.