A selection of past projects in Conservation Genetics
Conservation of the Harlequin Toad Gideon Bradburd, Yale EEB undergraduatestudent
The projects goals were to produce a phylogeny of the toad genus Atelopus and determine the genetic constitution of the Costa Rican Pacific coastal population of Atelopus varius, the Harlequin Toad, which was declared extinct in 1996 and rediscovered in 2003. Since its rediscovery, only 31 individuals have been documented, but through Gideon's fieldwork two additional individuals were discovered, one of them a juvenile, indicating that the population is still reproductively active. Using noninvasive swab samples for available members of the extant population and formalin-fixed tissue from historic museum specimens, an attempt was made to compare current levels of allelic diversity to historic levels, to obtain knowledge of the genetic health of the population.
Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the saltwater crocodile (Crocodylus porosus) on Palau
We have concluded a molecular assay on blood and tissue samples of the saltwater crocodile, Crocodylus porosus, indigenous to the Republic of Palau. The objectives of this study were to determine: 1) if the Palauan crocodile population is composed of one or more separate species, 2) if the population reflects the genetic influence of crocodilian species other than Crocodylus porosus, which may, inadvertently, have been introduced into the population, 3) the genetic and morphological characterization of Palauan crocodilians. These samples were used in conjunction with blood, skin and bone samples from other crocodilian species that may have been introduced into the population prior to WWII. These include the Siamese crocodile, Crocodylus siamensis; the Philippine crocodile, Crocodylus mindorensis; and the New Guinea crocodile, Crocodylus novaeguineae. Scalation morphology of Palauan crocodilians was also characterized. This project was a collaboration with Michael Russello, Gregory Watkins-Colwell, J. Gratten, and P. Braziatis, and several Yale undergraduates.
Publication: Russello MA, P. Brazaitis, J. Gratten, GJ Watkins-Colwell, and A. CACCONE. 2006. Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the saltwater crocodile (Crocodylus porosus) on Palau. Conservation Genetics, 8: 777-787.
The Komodo dragon is an endangered monitor lizard endemic to five Indonesian islands: Komodo, Rinca, Gili Motang, Nusa Kode (part of Komodo National Park) and Flores. Illegal hunting of prey species and habitat encroachment are main threats to the species, which now counts less than 3,000 individuals. Conservation initiatives for the Komodo dragon are a priority for the Indonesian Department of Forestry and Nature Conservation and quantitative data on the life history of extant populations is much needed in order to devise sound management plans.
A research project is being conducted in collaboration with the University of Florence, Italy, a newly established Indonesian NGO, Komodo Survival Program, the Indonesian Institute of Science and Department of Forestry and Nature Conservation. The study has so far provided information on the degree of genetic diversity among island populations, reconstructed the evolutionary history of the species and identified different gene pools as distinctive units for conservation. This, in concert with a comprehensive study on the degree of relatedness among captive Komodo dragons held in Indonesian zoos, represent a crucial information for future reintroduction and augmentation plans in areas where the species is now depleted. A population monitoring program is conducted along with Komodo National Park authority to provide annual estimates of population size, sex ratio and demographic structure. Home range and activity patterns of Komodo dragons in Komodo National Park are compared with those of animals living outside the protected area as a mean of assessing the effect of habitat disturbance.
Phylogeography of the Greater Prairie Chicken (Tympanuchus cupido) Including the Extinct Heath Hen Eric Palkovacs, Yale EEB graduate student
Discovering the importance of genetic structuring within and among populations of a species is extremely important for understanding population biology and evolution. The degree of genetic differentiation between populations and the role of subspecies in taxonomy have gained heightened attention due to our current conservation paradigm which relies heavily on subspecific distinctions for granting protection. In this project we explored the phylogenetic relationships among subspecies and populations of the greater prairie chicken (Tympanucus cupido). The greater prairie chicken complex represents three subspecies, two extant and one extinct. The most widespread subspecies is the greater prairie chicken (T. cupido pinnatus) of the Midwestern U.S. The Attwater’s prairie chicken (T. cupido attwateri), formerly of the Gulf Coast, is now highly endangered and restricted to a small isolated population in Texas. The heath hen (T. cupido cupido), formerly of the Northeastern U.S., was extirpated from mainland North America by around 1870, with a remnant population persisting on the island of Martha’s Vineyard, Massachusetts until its final extinction in 1932. We elucidated levels and patterns of genetic differentiation within and among subspecies and populations of greater prairie chickens based on mtDNA sequence analysis. The results of this research provide answers to important evolutionary questions but are useful in addressing conservation and management issues.
Publication: Palkovacs, EP, AJ Oppenheimer, E. Gladyshev, JE Toepfer, G. Amato, T. Chase, and A. CACCONE. 2004. Phylogeography of the Greater Prairie Chicken (Tympanuchus cupido) Including the Extinct Heath Hen: Potential Implications for Conservation and Management. Molecular Ecology 13: 1759-1769.