My goal as a paleoecologist is to understand what processes and factors gave rise to the diversity of organisms and ecosystems we see in the past and the present. It is also to understand how past ecosystems can inform our current relationships with ecosystems. My projects draw from many disciplines and integrate information from both extant and extinct organisms. By combining methods, I study processes across different temporal, geographic, and biological scales.
Linking Mammalian Omnivore Ecological Traits to Biogeography and Morphology
One of the main goals of ecology is to understand the rules that underly how species respond to environmental change, and specifically whole community response to resource shifts. A large proportion of mammals are omnivores (that is, they eat both plant and animal-based foods), but we do not know linkage between omnivorous dietary traits, key physical traits such as jaw shape, and the environment. This lack of knowledge also prevents paleontologists from reconstructing omnivorous diets in the fossil record, ultimately limiting more complete understanding of long-term processes underlying biological innovation. This project aims to better understand linkages between omnivorous diets and jaw and dental shape and how diet and shape are structured across communities and landscapes. The results of this project will help inform future estimates of how mammals and communities will respond to environmental changes (NSF Award #2209402).
Oregon Oligo-Miocene herbivore niche partitioning and community change
Ungulates are key primary consumers in terrestrial ecosystems. They directly affect the diversity of their predators, small herbivores, and vegetation; and today many are threatened with extinction. To better understand how ungulates (hooved mammals) responded to past climatic changes, I am investigating whether past species partitioned plant-food resources and how those ecological trends changed through time. Understanding how ecosystem change affected past ungulates, will increase our ability to predict which species will be affected by human actions. Past studies of ungulate functional diversity have focused on either the Great Plains or the onset of open grasslands which may not be representative of what occurred in the Pacific Northwest. I am using stable carbon and oxygen isotopic composition of fossil tooth enamel to understand changes in Oregon Oligo-Miocene ungulate diet composition. New local isotopic data and body mass estimates collected for this study will be a powerful tool for reconstructing Oregon’s herbivore ecological community structure over the past 20 million years.
What is a mammalian omnivore? Insights into omnivore diet diversity, body mass, and evolution
Proposed evolutionary pathways from carnivory to herbivory through omnivory. Q is median estimated transition rate. Figure from Reuter et al. 2018.
Ecological studies often categorize all omnivorous mammals as one dietary group; however, because omnivorous mammals are ecologically diverse, this practice results in the loss of important information. Understanding how different groups manifest omnivory will increase the accuracy of diet reconstructions for fossil mammals. To increase understanding of modern mammalian omnivores and improve paleoecological reconstructions of diet, I am investigating major evolutionary trends in mammalian diets. My study uses mammalian diet records to understand the dietary diversity within mammalian omnivores by quantifying which foods are most often eaten together. I also am looking at the relationship between omnivore body mass and food consumed to better predict diets of extinct organisms. Additionally, I am using Bayesian statistical modeling to understand how omnivorous diets evolve through time. My findings suggest that dietary specialization is highly successful but also constrained. My results also show transitions from one diet type to another are gradual and take paths through the various stages of omnivory. This work was presented at the Society of Vertebrate Paleontology Annual Meeting (Reuter et al. 2018) and is under review.
Mammalian Community Structure Through Time
My aim is to understand how mammalian community structure changes in response to vegetation and climate change. To do this I am reconstructing food webs for numerous faunal assemblages, covering a 28-million-years of Oregon’s fossil history. I spent the summer of 2017 as the Geoscientists-in-the-Parks Guest Scientist at the John Day Fossil Beds National Monument collecting data and reconstructing body masses for the fauna. I made preliminary food webs using modern predator prey relationships as a guide and presented them at 2017 Society of Vertebrate Paleontology annual meeting.
Carnivoran intraspecific tooth-size variation
Testing for differences in intraspecific variability among many species of carnivorans can give insights into how the morphology of the tooth row reflects diet, phylogeny, and potential developmental controls. I presented the results of this project at the 2016 SVP (Society of Vertebrate Paleontology) meeting. This project is FuTRES contribution #17. This paper is published in the Journal of Mammalogy https://doi.org/10.1093/jmammal/gyaa157.