Loss, Generation, and Maintenance of Ecomorphological Diversity in Marine Teleost Fishes: Deep Time Perspectives on a Contemporary Biodiversity CrisisEPA Grant Number: F6E21148
Title: Loss, Generation, and Maintenance of Ecomorphological Diversity in Marine Teleost Fishes: Deep Time Perspectives on a Contemporary Biodiversity Crisis
Investigators: Friedman, Matt
Institution: University of Chicago
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2006 through September 1, 2009
Project Amount: $111,172
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Oceanography and Coastal Processes
Analyses of long-term records reveal that modern marine ecosystems diverge considerably from pre-fishing conditions. Such ecosystem restructuring resulting from overfishing has been implicated in a host of environmental maladies, which in turn have been linked to additional cascades of extinctions. Despite concerns over the conservation of marine fish biodiversity, remarkably little is known of the factors contributing to the generation of this diversity.
The paleontological record is punctuated by mass extinctions that have been used to examine issues with a bearing on modern environmental crises, such as recovery dynamics and the correlates of extinction vulnerability. In addition, paleontological data uniquely records natural baselines for turnover rates and affords critical insights on the factors underlying the evolution of modern biodiversity. This research focuses on the history marine teleost fishes from the mid-Cretaceous (100 Ma) to the Recent, and spans two critical episodes in the assembly of modern ichthyofaunas: the Cretaceous/Tertiary (K/T) extinction, which resulted in the extirpation of many groups of fishes, and the Paleogene evolutionary radiation, which established the overwhelming bulk of modern teleost diversity, including many species targeted by marine fisheries.
The fossil record of fishes is an underutilized system for studying changing patterns of ecology over time, and provides the only direct evidence for the roots of Recent diversity. Research on living fishes has established the ecological significance of anatomical structures routinely preserved in fossils, but few paleobiological studies have incorporated these findings. Ecomorphological variation in fossil fishes will be summarized using geometric morphometrics, providing a database for testing hypotheses relating to two major topics.
The first part of this research focuses on the effects of the Cretaceous/Tertiary (K/T) extinction event on marine teleosts. I will (i) test if this extinction demonstrated ecomorphological selectivity, and, if so, will (ii) determine if victims are characterized by features linked to elevated extinction risk in Recent organisms. The anatomical and functional correlates of extinction risk identified by this study could be used to predict which modern fishes may be more vulnerable.
The goal of the second component of this research is to examine patterns of ecomorphological change subsequent to the K/T extinction among acanthomorphs, a major group of marine fish that includes many economically important taxa. Results from these analyses will shed light on the generation of Recent biodiversity by (i) establishing baseline rates of taxonomic and ecological turnover among marine fishes, (ii) determining if ecological incumbents influence the morphologies realized by newly originating taxa, and (iii) investigating the role of biogeography in the development of biodiversity by examining the geographical partitioning of ecomorphological variety during a major evolutionary radiation.
It seems likely that the K/T extinction was selective with respect to ecomorphology, and that those groups characterized by features known to correlate with extinction risk in living organisms (body size, high trophic level) were disproportionately affected by this event. Baseline rates of taxonomic and morphological turnover in fishes appear to be lower than those of terrestrial vertebrates, further emphasizing the severity of the effects arising from overfishing.