Research
Utah Caves Project
Climate Change and Utah's High Elevation Ecosystems
The use of fossil data to inform contemporary conservation is essential for sustaining biodiversity. This is because as human impacts on ecosystems accelerate, there is a growing emphasis in conservation planning towards maximizing the capacity of ecosystems to respond to anticipated changes in the near future. Doing so requires understanding how ecosystems responded to past changes that occurred over timescales exceeding those of direct human observation. The fossil record provides these data and documents baselines of animal communities that can be used to evaluate the impacts of historic, human-induced climate change and attest to the responses of species to ecosystem changes over geological timescales. In this ongoing research project we are studying animal remains recovered from Utah’s high-elevation cave deposits to establish what animal communities looked like before human-induced climate change. We then compare these past records with recent zoological survey data to evaluate whether ongoing climate change has contributed to range shifts or local extinctions, as has been predicted for the region’s montane mammals. This work is interdisciplinary and sits at the intersection of Anthropology, Ecology, Geology, and Climate and Environmental Science, and has implications for contemporary ecological restoration, conservation, and wildlife management projects.
Image of project collaborators Dr. Tyler J. Faith and Dr. Randall Irmis collecting faunal material from a cave deposit.
Restoring Indigenous Socico-Environmental Systems (SES) in the Bear River Basin
Findings from the Utah Caves Project will contribute to an interdisciplinary research project in collaboration with the Northwestern Band of the Shoshone Nation on a project to restore Indigenous SES in the Bear River Basin, straddling modern-day Idaho, Utah, and Wyoming. This interdisciplinary project couples archaeological, paleoecological, ethnographic, and oral and archival history to explore past human-environment interactions under conditions of climate change and inform the Tribally-led restoration process. Within this project, I am a member of an interdisciplinary team funded by an NSF Dynamics of Integrated Socio-Environmental Systems grant (Aug. 2023 - pres.), advancing this work.
The image identifies the extent of the project area. Map credit: Ishmael Medina
The above research projects are associated with the Science Research Initiative at the University of Utah,
supporting student-led research projects.
Meet the research team here.
Holocene Subsistence Behavior in Western North America
Human settlement density, not late Holocene climate change, influenced Artiodactyla species abundance in northeastern California faunal assemblages
Variation in late Holocene artiodactyl (e.g., deer, pronghorn, bighorn sheep) hunting in northern California has been examined from a behavioral ecological perspective to understand past foraging and land-use practices and related changes in human behavior, including settlement patterns, technological change, social signaling, large-scale resource intensification, and anthropogenic resource depression. However, rarely are past climate records and proxies of human population density coupled with zooarchaeological estimates of large game abundance to evaluate the ecological and anthropogenic drivers of changes in species representation over time. To better understand changes in human behavior related to past large game hunting, collaborators and I are disentangling the causal relationships between late Holocene climate change, human demography, and artiodactyl abundance to assess whether climate change, human hunting, or both impacted the abundance of large game in zooarchaeological assemblages from northeastern California. We found that expanding human settlement density and related increases in logistical foraging—not late Holocene climate change—directly impact the relative abundance of large game in these assemblages. Additionally, our findings reveal that the effects of climate change are entirely mediated through human settlement density. Ongoing research building from this project is focused on understanding how patch use decisions influenced large game hunting in the region (forthcoming publication in prep).
Figure shows a summary of piecewise structured equation models. Panel (a) shows coupled impacts of mean winter (snowflake) and summer (rain cloud) precipitation (mm/ day) on both human settlement density (human) (SPD cal 14C) and artiodactyl abundance (pronghorn), and of human settlement density on artiodactyl abundance. Panel (b) depicts the coupled impacts of mean winter and summer precipitation on human settlement density, and of human settlement density on artiodactyl abundance. Dashed lines indicate indirect and non-significant relationships and solid lines indicate direct and significant relationships at the 0.01 alpha level. Results indicate that panel (b) is the more parsimonious model. Here, winter and summer precipitation directly impact human settlement density, but only human settlement density directly impacts relative artiodactyl abundance.
For more see (* indicates undergraduate student co-author):
Cole, Kasey E., *Moffatt, Maren, Codding, Brian F., Broughton, Jack M., (2024). Human hunting pressure, not late Holocene climate change, influenced Artiodactyla species abundance in northeastern California faunal assemblages. Quaternary International. DOI: https://doi.org/10.1016/j.quaint.2023.10.006
Late Holocene tule elk (Cervus canadensis nannodes) resource depression and distant patch use in central California: Faunal and isotopic evidence from King Brown and the Emeryville Shellmound
Previous research has documented declines in the abundance of high-return resources including tule elk (Cervus canadensis nannodes) over the past three millennia in central California, suggesting the occurrence of resource depression. In this study, collaborators and I test the hypothesis that hunting depressed tule elk in this setting by articulating stable isotope analyses from tule elk specimens with data on the age structure and skeletal part representation from the King Brown and Emeryville Shellmound sites. At King Brown, located within California's Central Valley and vast tule elk freshwater marsh and grassland habitat, we find increasing isotopic diversity, a decline in mean age, and an increasing abundance of high-utility skeletal elements, all suggesting local depression stimulated the increasing use of distant elk patches. At Emeryville, located on the shore of the San Francisco Bay where limited elk habitat existed, faunal trends are consistent with elk depression, and there is no observed evidence of distant elk patch use. Our work underscores how human behavioral responses to resource depression can vary with the local ecology as they affect patch use economics for specific prey and demonstrates how such responses can be deciphered through stable isotope and faunal data.
For more see (** indicates graduate student co-author):
Broughton, Jack M., **Broughton, Michael J., Cole, Kasey E., **Dalmas, Daniel, and Coltrain, Joan B., (2023) Late Holocene tule elk resource depression and distant patch use in central California: faunal and isotopic evidence from the King Brown site and Emeryville Shellmound. Journal of Anthropological Archaeology. DOI: https://doi.org/10.1016/j.jaa.2023.101512
Assessing how Socioecological Factors Influence Human Social Organization, Inequality, and Territoriality
Hunter-Gatherer group size and lifetime interaction rates
Humans are relatively unique in terms of their social organization in that they regularly live and cooperate with non-kin. Collaborators and I are exploring how factors of human group size and interaction rates may be influenced by socio-ecological conditions. In particular, we are interested in how the economy of scale of key resources can benefit cooperation, and how the availability and sustainability of these resources may incentivize various mobility strategies leading to differences in how many people an individual interacts with over their lifetime. Early results draw attention to how socio-ecological conditions may set the stage for human prosociality and cooperation. Continued agent-based modeling work, paired with ethnographic data is ongoing.
For more see:
Codding, Brian F., Cole, Kasey E., and Wilson, Kurt M., (under review). Exploring the ecological foundations of uniquely human social organization.
Codding, Brian F., Cole, Kasey E., and Wilson, Kurt M., (2022). Socioecological factors influence hunter-gatherer group size, lifetime interactions, and emergent properties of culture. In Scale Matters: The Quality of Quantity in Human Culture and Society edited by Thomas Widlok and M. Dores Cruz. Transcript Verlag, Bielefeld, Germany. https://www.transcript-verlag.de/978-3-8376-6099-9/scale-matters/
Identifying key socio-ecological factors altering expressions of egalitarianism and inequality among foragers
Identifying factors that favor egalitarian versus non-egalitarian resource access and behavioral patterns is a longstanding anthropological research interest, though it is incredibly difficult to study archaeologically and many external causal factors have been nominated as driving forces incentivizing inequality. Collaborators and I built an agent-based model incorporating ecological conditions, behavioral theory, and individual interactions to assess how changes in key environmental conditions may incentivize egalitarianism or inequality more strongly. Preliminary results suggest that resource distribution and predictability are key ecological factors that interact with human decisions and structure behavioral outcomes.
For more see:
Wilson, Kurt M., Cole, Kasey E., Codding, Brian F., (2023). Identifying key socio-ecological factors influencing the expression of egalitarianism and inequality among foragers. Philosophical Transactions of the Royal Society B. DOI: https://10.1098/rstb.2022.0311
Social boundaries, resource depression, and conflict: A bioeconomic model of territory formation
Human territoriality and the evolution of social boundaries are important and longstanding issues of concern to anthropologists and social scientists. One notable phenomenon is the intertribal buffer zone, an area that is generally devoid of occupation where certain resources can flourish without being overhunted. Here, we develop a bioeconomic model to assess the relative importance of resource depression and conflict on the formation of the buffer zone. We first develop a dynamic spatial model of a human group harvesting a large game resource at varying distances from a residential base locale. We then introduce a second human group and evaluate the model under two assumptions regarding the interaction between groups: (1) the groups maintain an amicable relationship and both harvest the game, and (2) the groups are hostile and engage in conflict as each hunt for game. We show how the potential for conflict reduces the incentive to harvest high-ranking resources and prevents the overexploitation of resources in the buffer zone.
For more see:
Bayham, Jude, Cole, Kasey E., and Bayham, Frank E., (2019) Social boundaries, resource depression, and conflict: a bioeconomic model of territory formation. Quaternary International (518) 69-82. DOI: https://doi.org/10.1016/j.quaint.2017.11.007
Improving Methods for Zooarchaeological Taxonomic Identification
Cole et al. (2022) Fig. 4: Summary results for evaluations with leporid data. "+" and "-" represent quantiles in the distributions. Results indicate that RF misidentified cranial leporid data less often than LDA and PCA.
Faunal analyses depend on accurate taxonomic identifications, but distinguishing between morphologically similar fauna is not always possible through visual comparisons with comparative reference skeletons. Previous research has addressed this limitation through morphometric modeling using Linear Discriminant Function Analysis (LDA) or Principal Component Analysis (PCA). However, both approaches are limited by their assumptions and their ability to estimate error, constraining their empirical use for identifying faunal specimens. Random Forest (RF), a machine learning method, can resolve these limitations. Here, we evaluate the predictive power of LDA, PCA, and RF for taxonomic identification using morphometric modeling to determine which approach is best suited for faunal analyses. Results indicate that RF outperforms LDA and PCA. RF more accurately predicts species identification with a complete dataset and when missing measurement data are interpolated.
For more see:
Cole, Kasey E., Yaworsky, Peter M., and Hart, Isaac A., (2022) Evaluating statistical models for establishing morphometric taxonomic identification and a new approach using Random Forest. Journal of Archaeological Science, 143 (105610). DOI: https://doi.org/10.1016/j.jas.2022.105610