Research Interests

Contact Information

Assistant Professor
Anatomy Department
Des Moines University
3200 Grand Ave
Des Moines, IA 50312
Phone: 515-271-1568
Fax: 515-271-1675
Email: julie.meachen@dmu.edu
Follow me on Twitter: @SaberCatWoman

My Research

My research involves examining the morphology of extant and extinct vertebrates, with a focus on the mammalian order Carnivora, to investigate how these animals co-exist, evolve and adapt to biotic and environmental change. I am interested in functional adaptations as tools for examining species ecological interactions in the past and present to make predictions for future generations of species.  To answer these functional questions I use a morphometric approach which involves a combination of techniques including geometric morphometrics, radiographs, CT scans, and linear measurements. I am also interested in paleontological fieldwork and have participated in field work from sites across the U.S. from Florida to Idaho.

Current Projects

Carnivore postcranial disparity: adaptations to climate and habitat

Following from my original NESCent project involving carnivore guild structure, I have started a project in collaboration with Lars Werdelin of the Swedish Museum of Natural History which examines the functional diversity of extant carnivorans to investigate the influences of temperature, precipitation and habitat type on postcranial morphology. Our questions for this project include: How does variation in habitat and climate induce morphological variation? How is the relationship between habitat/climate and morphological variation constrained by phylogeny? And are habitat and/or climate related to functional richness in carnivore communities?

To answer these questions we have combined linear measurements with multivariate analyses to examine morphological disparity and how it relates to climate and habitat.



Natural Trap Cave revisited: ancient DNA, climate and the megafaunal extinctions

With funding from National Geographic and my home institution, Des Moines University, we held our inaugural field season for this unique site from July 27 through August 9, 2014. The first field season was a success! We found a wide array of ice age mammal fossils and many many microfaunal fossils. This past year I have also received NSF funding for this project to continue for the next two years (summers of 2015-2016). This project is in conjunction with Co-PI Alan Cooper of the University of Adelaide . We re-opened this exceptional site with the goal of investigating causes of the megafaunal extinction and paleoecological responses to climate change at the end of the Pleistocene. NTC gives us the opportunity to track genetic changes through a long period of time that spans the pre- to post-extinction events. A key strength of our approach is to bring a broad range of scientific methods and researchers together so that the same materials are analyzed using morphological, biogeochemical, and genetic techniques. This synergistic approach will establish a new standard for the analysis of recent paleontological material and promises to produce a far more resolved picture of paleoecological change than has previously been possible. Using ancient DNA, accelerated mass spectrometry (AMS) radiocarbon dates, ash-layer dating, stable isotope analyses, and results from previous studies of NTC we will correlate the timing of the extinction with climate records and genetic variation in species found at this locality. Here, we investigate the questions:  Was the Pleistocene extinction event preceded by, or concurrent with a large loss of genetic variation? Do mammal species that did not go extinct exhibit similar genetic changes? Can population metastructure be detected through time, and how is this influenced by climate?

Please contact me if you would like more information on this project. Please stay tuned for the dates of next summer's field season. 

Radiocarbon dating and the extinction events at Rancho La Brea

Along with collaborators Robin O’Keefe from Marshall University and Wendy Binder from Loyola Marymount University, I am involved in a project at Rancho La Brea that will examine the timing and causes of the mass extinction event as it happened at this locality. We are examining changes through time and in relationship to climate in the carnivores from Rancho La Brea. We are also hoping to extensively radiocarbon date the pits at Rancho La Brea so we can pinpoint the timing of important ecological events. This project is in conjunction with the AMS lab at UC Irvine and John Southon. We hope to answer the questions: What is the timing of the extinction event at Rancho La Brea? Was climate driving size change at Rancho La Brea? Were the "tough times" correlated with a specific climate or environmental change?

We are currently applying for funding for this project through NSF. We are also planning a working group to discuss La Brea ecology and environment.
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