『High resolution life history records from biomineralized tissue: a tool for conservation paleobiology』
Dr. David Dettman University of Arizona
Studying the conservation biology of rare, remote, or endangered animals presents significant challenges because these animals cannot easily be observed, captured, or killed. In addition, there is often a lack of baseline data on the environment in which these animals thrived prior to human modification. Using the remains of dead animals or specimens from museums or archaeological sites can provide information on the habitat and climate in which the animals lived. This talk discusses "conservation paleobiology" - the application of paleontological and geochemical techniques to the study of endangered species.
Hard tissues like mollusk shells and fish otoliths contain geochemical records of the environment in which the animals lived. Using life history reconstructed from the hard-parts of two endangered fish, Totoaba macdonaldi and Cynoscion othonopterus. We can see that they relied in the lower salinity estuary zone at the mouth of the Colorado River early in their life. After the damming of the river this brackish zone disappeared and growth rates in these fish declined significantly. The nearly extinct Mulinia coloradoensis, an endemic bivalve in the northern Gulf of California, has also been affected by the change in the Colorado River delta from a low salinity area to a hypersaline environment. Stable isotope geochemistry is used here to document the pre-dam salinity regime in the delta region. Taphanomic analysis also shows that the decline of M. coloradoensis had a major impact on Colorado River delta predators (snails and crabs).