Thesis (Ph. D.)--University of Oregon, 2001. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 121-147). Also available for download via the World Wide Web; free to University of Oregon users.

Headstarting is one of the more recent practices being used to maintain endangered populations in the wild. A headstart program was developed for the Jamaican iguana, Cyclura collei, in 1991 after its rediscovery in 1990. This current study tests the hypothesis that this population is experiencing a reduction in effective population size in spite of an increasing census population size due to the small number of nests available in the early years of the headstart program. A total of 875 individuals collected from 1991 to 2011 were genotyped at twelve variable microsatellite loci. Results from this study indicate a slight but significant decline in genetic variation (3% loss), and a modest proportional reduction in effective population size (0.075), since the initiation of the program. However, it is important to note these data also suggests that effective population size of this population is stabilizing.

Inbreeding depression affects captive populations and those that have been recently impacted by anthropogenic disturbance. However, the evolutionary importance of inbreeding depression in natural populations is not well understood. This study focuses on a naturally small population of Cyclura carinata, the Turks and Caicos Rock Iguana, that has likely been stable for hundreds of generations. Genotypic data at 13 polymorphic microsatellite loci, along with fitness proxies, were collected from 188 individuals across three age classes. Multi-locus heterozygosity is strongly predictive of age class (p < 0.03), and is significantly lower in hatchlings than in juveniles or adults. Estimates for intensity of selection favoring heterozygosity range from 0.498-0.627, indicating that this proportion of individuals fail to survive due to inbreeding depression. The heterozygosityitness correlation among adults is significant (p < 0.01), suggesting outbred individuals have higher reproduction success. Hence, the lifetime influence of inbreeding on fitness is extremely high.

In this study, we used ostensibly neutral microsatellite markers to study genetic variance and heterozygosity of endangered Cyclura lewisi during captive management in the Blue Iguana Recovery Programme. We assessed the variation present in the founding population and how genetic diversity changed throughout the past 20 years of management. We also studied how heterozygosity may correlate with fitness through morphometric measures and success of recruitment after release into the wild. While we found a reduction in effective population size, standardized heterozygosity, and fixation indices did not significantly change from the founders to later generations. We found no evidence for inbreeding depression in the captive population but a significant difference in heterozygosity of animals released to the Salina Reserve. Lastly, we found little evidence to support heterozygosityitness correlations using morphometric measures.

Indiana University-Purdue University Indianapolis (IUPUI) / The West Indian iguanas of the genus Cyclura are the most endangered group of lizards in the world (Burton & Bloxam, 2002). The Ricord’s iguana, Cyclura ricordii, is listed as critically endangered by the International Union for Conservation of Nature (IUCN) (Ramer, 2004). This species is endemic to the island of Hispaniola (Figure 1), and can only be found in limited geographic areas (Burton & Bloxam, 2002). The range of this species is estimated to be only 60% of historical levels, with most areas being affected by some level of disturbance (Ottenwalder, 1996). The most recent population estimation is between 2,000 and 4,000 individuals (Burton & Bloxam, 2002). Information on potentially suitable habitat can help the conservation efforts for Ricord’s iguana. However, intensive ground surveys are not always feasible or cost effective, and cannot easily provide continuous coverage over a large area. This paper presents results from a pilot study that evaluated variables extracted from satellite imagery and digitally mapped data layers to map the probability of suitable Ricord’s iguana habitat. Bayesian methods were used to determine the probability that each pixel in the study areas is suitable habitat for Ricord’s iguanas by evaluating relevant environmental attributes. This model predicts the probability that an area is suitable habitat based on the values of the environmental attributes including landscape biophysical characteristics, terrain data, and bioclimatic variables.

Thesis (M.S.)--Indiana University, 2009. / Title from screen (viewed on August 27, 2009). Department of Geography, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Jan Ramer, Aniruddha Banergee, Jeffery Wilson. Includes vita. Includes bibliographical references (leaves 47-52).

Entre los vertebrados más amenazados del planeta se encuentran las iguanas (Iguanidae: Iguaninae) por la pérdida de hábitat, la sobreexplotación, la presencia de especies invasoras y disturbios humanos. El género Cyclura, grupo de grandes lagartos iguánidos, se encuentra distribuido en la región del Caribe a través de las Antillas Mayores, y constituye un elemento conspicuo de la herpetofauna de estos lugares. La iguana cubana (Cyclura nubila nubila) aún es relativamente abundante pero se encuentra evaluada como Vulnerable con una tendencia poblacional al decline y su vulnerabilidad podría incrementarse. En el archipiélago cubano, se encuentra presente en la isla grande de Cuba y en cayos situados al norte y al sur de la isla. Sin embargo, se desconoce si existen diferencias entre los individuos que habitan la isla grande o los cayos. Conocer la existencia de estas diferencias es deseable bajo el marco conceptual de la biología de la conservación, puesto que resulta deseable que las diferentes poblaciones y sus características se protejan y se aplique un manejo diferenciado si fuera el caso, constituyendo lo que se conoce como Unidades de Manejo independientes. Por otro lado, el calentamiento global es inequívoco, evidenciado por cambios meteorológicos y climáticos extremos. Como respuesta a estos cambios ha sido observado que muchas especies han modificado su distribución geográfica, estacionalidad, patrones migratorios, abundancia e interacciones interespecíficas. El presente trabajo de tesis doctoral tiene como objetivos principales analizar la existencia de diferencias poblacionales de la iguana cubana en el archipiélago cubano, y evaluar el efecto potencial del cambio climático sobre la distribución geográfica de esta especie para los años 2050 y 2070, identificando las variables climáticas que más influyen en dicha distribución, las zonas climáticamente idóneas para la especie, y valorando la cobertura que ofrece el Sistema Nacional de Áreas Protegidas para la supervivencia de la especie mediante la elaboración de modelos predictivos en diferentes escenarios de cambio climático futuros. Se observó un marcado dimorfismo sexual favorable a los machos, en relación a la longitud hocico-cloaca, el largo de la cabeza y el peso. Se encontraron diferencian entre las poblaciones de cayos y las de Cuba. Los resultados muestran que la extensión del área donde habitan estas poblaciones es un factor que influye en algunas de las medidas corporales como la talla y el peso, y se constató que ambos sexos presentan similares capacidades para reptar, correr y reptar/correr, lo que les permite disponer de similares potencialidades para la utilización de los recursos y el espacio disponible. Los modelos predictivos de distribución mostraron valores de idoneidad climática en una extensión aproximada de 38 720 km2, fundamentalmente en zonas de baja altitud y relativamente cercanas a la costa, lo que representa 37 % de la superficie del archipiélago cubano. La temperatura mínima durante el mes más frío y la temperatura media anual fueron las variables de mayor importancia en el modelo. Los resultados sugieren que las distintas poblaciones descritas de la especie deben protegerse y manejarse de forma diferenciada para lograr su efectiva conservación. Asimismo, el monitoreo de las poblaciones de iguanas en áreas protegidas y fuera de ellas resulta necesario para evaluar los impactos que eventos extremos (incendios o huracanes) o prolongados (actividades humanas), producen en las mismas, así como probar la eficacia de las áreas protegidas en la conservación de la especie. Finalmente se discuten algunas implicaciones de los resultados de este estudio para el manejo de las poblaciones.

Cyclura ricordii is an endemic iguana from Hispaniola and is listed as Critically Endangered on the IUCN. The main threats are predation by introduced mammals, habitat destruction and hunting. The present study focused on two nesting areas in Pedernales in the Dominican Republic. The hypothesis tested is that natal philopatry influences dispersal and nest site selection. Monitoring and sampling took place during 2012-2013. Polymorphic markers were used to evaluate whether natal philopatry limits dispersal at multiple spatial scales. Ripley’s K, revealed that nests were significantly clustered. Hierarchical AMOVA revealed that nest site aggregations did not explain a significant portion of genetic variation. However, Mantel’s tests revealed significant positive correlations between genetic and geographic distance. These results indicate that natal philopatry limits dispersal at a course spatial scale, but does not influence nest site selection at a fine spatial scale.