Record Details

Yacelga, M;Cayot, Linda J;Jaramillo, A
Dispersal of neonatal Galápagos marine iguanas Amblyrhynchus cristatus from their nesting zone: natural history and conservation implications
Herpetological Conservation and Biology
Journal Article
Amblyrhynchus cristatus
Neonatal dispersal is an essential component of metapopulation systems, resulting in changes in demography, population dispersion, colonization, and gene flow. We studied the dispersal of neonate Marine Iguanas (Amblyrhynchus cristatus) from their nesting zone on Santa Cruz Island, Galápagos. Dispersal patterns appeared to be related to coastal topography, as Marine Iguanas sought out necessary habitat requirements for foraging, refuge, and thermoregulation. We also observed that the dispersal of hatchlings was highly synchronized with the tidal schedule and exposure of algae in the intertidal zone through low tide. The timing of low tide influenced dispersal such that when it occurred at daybreak, early morning, or late afternoon, the iguanas did not disperse. Low ambient temperature (overcast days) and the presence of avian predators also significantly diminished dispersal. We observed 894 (range: 0-128/2h per day) neonate iguanas (both marked and unmarked) dispersing from the nesting zone along the coastline of Santa Cruz for distances sometimes > 6 km. Of the 246 marked iguanas we found outside nesting grounds, > 94% dispersed westward, while only 5% dispersed eastward. These observations indicate that abiotic and biotic pressures may result in trade-offs in how neonates select particular habitats out of their natal area. They also may account for previous reports of the negligible survivorship of some Marine Iguana populations on islands with introduced predators.