Presenter: Eva Biedron
Faculty Mentor: Samantha S. B. Hopkins, Edward B. Davis
Presentation Type: Oral
Primary Research Area: Science
Major: Geological Sciences, Biology
Relationships between mammal species and their preferred habitats are often used to reconstruct past ecology in fossil ecosystems. Ungulate herbivores, whose teeth reflect their diet, are one of the most common terrestrial mammal groups used in habitat reconstruction. However, small mammals, like squirrels, may sample over a narrower geographic range and offer a more sensitive signal. If squirrels and ungulates show the same paleoecological signal in the fossil record, squirrels could be used as a new habitat indicator taxa.
We hypothesized open-habitat squirrel taxa would be found in assemblages dominated by grazing ungulates and closed-habitat sciurid taxa would be found in assemblages dominated by browsing ungulates. We compiled a dataset of 25 Oregon fossil localities (aged mid-Miocene to Recent), including specimen data and ecology, using the MioMap and Fossilworks Paleobiology database. We calculated the chord distance between each unique pair of sites to understand the differences in dominant squirrel and ungulate ecologies.
We found the chord distance values of squirrels form three distinct clusters while ungulate chord distance values do not cluster, indicating differences between sciurids and ungulates as habitat indicators. The differences between these large and small mammals in home range size may yield different information about a heterogeneous landscape. If so, these results suggest sciurids and ungulates are both useful as paleoecological indicators, but at different spatial scales.