A Late Pleistocene Demographic Winter Due to Global Warming?
Lead Research Organisation:
University of Aberdeen
Department Name: Archaeology
Abstract
With the ongoing climate crisis and global erosion of biodiversity, it is now of prime concern to better understand how ecosystems react to long-term climatic and anthropogenic stressors. In the late Pleistocene (~50,000-12,000 years ago), numerous species of mammalian megafauna (i.e. weight > 44 kg) experienced significant population declines ('bottlenecks'), or even total species extinction (e.g. woolly mammoths, cave bears), that coincided with major climatic changes and the growing presence of human populations in all continents. The development of new techniques, including paleogenetics and geochemistry, are beginning to help us understand these demographic collapses and their ecological consequences. However, the relative impacts of climatic and anthropogenic factors on these demographic changes remain debated in many cases. One reason for this arises from the complexity of assessing key aspects of past population dynamics (e.g. fertility rates) with currently available methods. However, recent studies have shown that the calcium (Ca) in the skeleton is isotopically different between conspecific individuals that reproduce and lactate to different extents. This discovery provides a unique opportunity to study reproduction behaviors and aspects of fertility rates through time based on fossil remains. PleistoDem will target a range of modern and fossil species, such as reindeers, mammoths and cave bears, from different locations in Europe and North America, representing the first largescale study using these techniques. Ca isotopic analyses will be integrated in a broader multi-proxy framework including stable light and strontium isotopic systems, in order to consider reproduction rates and behaviors within a high-resolution picture of past ecology, environment and mobility. This ground-breaking project will improve our understanding of Late Pleistocene ecological changes, which in turn will provide a solid base to anticipate and face future ecological changes.
People |
ORCID iD |
| Kate Britton (Principal Investigator) |
| Description | This award has so-far led to the development of new analytical methods in archaeology/palaeontology, including the developing of a new methodology for measuring calcium isotopes in fossils. This expands the range of instrumental configurations Ca isotopes can be analysed with. Ongoing work on large animals is highlighting several new trends: 1) is that our modern-controlled-study investigations seem to highlight that Ca isotopes are not a precise demographical proxy for reindeer/caribou, likely due to the short period spent nursing. While a negative result, this has served to inform us more about the usefulness and potential of this method. 2) Our study of modern African elephants has highlighted that Ca isotope tusk record is weakly affected by nursing. Other promising results from this study suggest that isotope records in tusk might record diet and past environmental disturbances, such as droughts - and unexpected but interesting result. |
| Exploitation Route | The newly developed methodology provides accurate and reproductible data. This allowed to investigate the key questions of this project, and to expand the range of laboratories that could readily run these measurements in the future, therefore favouring the development of the field of Ca isotopes in academia as a whole. The current results are serving to strengthen our understanding of how Ca isotope analyses might be applied to fossil animals and to understand the parameters of what can be investigated. While this might mean that some of the initial objectives will not be able to be addressed in the manner planned, this is important method development for the field as a whole and is leading to several method-development and test-of-concept studies. For example, while the modern elephant and caribou data suggest that Ca isotopes cannot provide information about extant and extinct proboscidean demographics/fecundity, the results instead suggest that these approaches could provide valuable insights about diet and environmental threats faced by these animals. This discovery holds promise in better understanding the impact of past and present climate changes on land ecosystems. |
| Sectors | Environment Culture Heritage Museums and Collections Other |
| Description | Collaboration with Harvard University (Cambridge, USA) |
| Organisation | Harvard University |
| Department | Department of Earth and Planetary Sciences |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Study design, sample preparation, analyses. |
| Collaborator Contribution | Study design, sharing of samples. |
| Impact | Access to samples with high scientific value for PleistoDem, generation of valuable data for the project, ongoing data processing and future publication. |
| Start Year | 2023 |
| Description | Collaboration with University of Utah (Salt Lake City) |
| Organisation | University of Utah |
| Department | Department of Geology and Geophysics |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Study design, sampling, sample preparation, analyses. |
| Collaborator Contribution | Study design, sharing of samples and facilities. |
| Impact | Access to samples with high scientific value for PleistoDem, generation of valuable data for the project, ongoing data processing and future publication. |
| Start Year | 2023 |
| Description | Collaboration with the National Reasearch Council of Canada (NRC metrology, Ottawa) |
| Organisation | National Research Council of Canada |
| Country | Canada |
| Sector | Public |
| PI Contribution | The collaboration with the NRC involves jointly developing metrologically sound Ca isotope analyses and associated standards using UOttawa's isotope geochemistry and sample preparation expertise. |
| Collaborator Contribution | The collaboration with the NRC involves jointly developing metrologically sound Ca isotope analyses and associated standards using the NRC's metrological and measurement platforms. |
| Impact | Data to validate the methods for Ca purification and isotopic analysis (pivotal to the project). The research framework of PleistoDem and the nexus with metrology will allow advancement of both geosciences and metrology and standards. |
| Start Year | 2023 |
| Description | Collaboration with the University of Alaska Fairbanks and Large Animal Research Station (LARS) |
| Organisation | University of Alaska Fairbanks |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Developing new methods of behavioral and ecological postmortem monitoring. |
| Collaborator Contribution | Providing reindeer skeletal remains and field observations for method development. |
| Impact | The above mentioned skeletal remains have been received and prepared for incoming analyses. |
| Start Year | 2022 |
| Title | rerollR (R package) |
| Description | This R package allow to make population comparison tests while computing intra-individual uncertainty of measurement. |
| Type Of Technology | New Material/Compound |
| Year Produced | 2023 |
| Open Source License? | Yes |
| Impact | This R package is aimed to be used by scientists around the world to add a layer of discussion to population comparisons with an important measurement uncertainty component at the intra-individual level. |
| URL | https://github.com/a-hassler/rerollR |
| Description | Poster presentation and oral talk contribution at the Goldschmidt 2023 conference |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Thousands of researchers and students came to the Goldschmidt 2023 conference hosted in Lyon. Two oral talks with indirect link to PleistoDem and one poster with direct link to PleistoDem have been presented during this week conference. These have attracted the attention of researchers and students from various geochemistry fields, stimulated questions and debate, planted the seed for future collaboration, improved the impact of these works at the scale of the scientific community. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://conf.goldschmidt.info/goldschmidt/2023/goldschmidt/2023/meetingapp.cgi |