Catastrophic Reproductive Failure, Terrestrial Survival, and Persistence of the Marbled Salamander

• Published in: Conservation biology Vol. 20; no. 3; pp. 792 - 801
• Main Authors: TAYLOR, BARBARA E., SCOTT, DAVID E., GIBBONS, J. WHITFIELD
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.06.2006; Blackwell Science; Blackwell; Blackwell Publishing Ltd
• Subjects: Ambystoma - physiology; Ambystoma opacum; Amphibia. Reptilia; Amphibians; Animal behavior; Animal reproduction; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Breeding; catastrophic reproductive failure; Caudata; Computer Simulation; Conservation biology; Conservation of Natural Resources; Conservation, protection and management of environment and wildlife; denso dependencia de larvas; Ecosystem; efectos de almacenamiento; extinción; extinction; Female; Female animals; fracaso reproductivo catastrófico; Freshwater; Fundamental and applied biological sciences. Psychology; Highlands; Larvae; larval density dependence; Life span; modelo poblacional; Models, Biological; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; pond-breeding salamander; Ponds; Population Dynamics; population model; Reproduction - physiology; Reptiles & amphibians; Salamanders; salamandra de reproducción acuática; storage effects; supervivencia terrestre; Survival Rate; terrestrial survival; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Wetlands; South Carolina; USA, South Carolina, Rainbow Bay; Terrestrial environment; larval density dependence; pond-breeding salamander; terrestrial survival; Extinction; Caudata; Amphibia; Survival; Breeding site; catastrophic reproductive failure; Persistence; Breeding pond; Vertebrata; Ambystoma opacum; Storage; Larva; storage effects; population model; Developmental stage; Density dependence; Models; Aquaculture; Environmental protection
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/j.1523-1739.2005.00321.x

Wide variation in reproductive success is common among amphibians that breed in seasonal ponds, but persistence of adults can buffer against these fluctuations, particularly for long-lived species. We hypothesized that the frequent episodes of catastrophic failure of the marbled salamander (Ambystoma opacum enhance the importance of high terrestrial survival. At Rainbow Bay in South Carolina reproductive success was poor (< 1 metamorph/breeding female) in nearly half of the 22 years that the species bred. Complete failure occurred in 6 of 22 years. To study catastrophic failure, we adapted an age-structured, individual-based model with density-dependent growth and survival of larvae. The model was based on extensive data from local field studies and experiments. With consistently good survival in the pond stages, the simulated population required survival probabilities in the upland stages (juveniles and adults) near 0.5/year to persist and near 0.8/year to achieve the increases observed. Catastrophic failure, occurring randomly with probability 0.5/year, created additional fluctuations in the population, raised the thresholds of survival required for persistence, and caused extinction under conditions that were otherwise favorable. The marbled salamander at Rainbow Bay is not at great risk of extinction because of catastrophic failure, but the risk increases dramatically if life span is decreased or frequency of failure is increased. Any reduction in terrestrial survival will have deleterious consequences by reducing the breeding populations at equilibrium, even if it does not jeopardize persistence. Our model provides assessments of risk that can be applied to poorly studied species with similar life histories, such as the endangered flatwoods salamander (A. cingulatum).