A long-term initiative monitoring and recording ancient animal footprints found along 3.1km of the coastline at Formby, just north of Liverpool, has revealed that habitat loss in the late Mesolithic and very early Neolithic period may have had a negative impact on animal diversity in the area.
Between 2010 and 2016, researchers from the University of Manchester meticulously documented the tracks of hundreds of different animals as they became exposed by wave erosion beside the Irish Sea (see CA 318). Recent radiocarbon dating of in situ plant material recovered from 20 of these sediment beds – carried out at the 14CHRONO Centre at Queen’s University Belfast – has revealed that they span at least 8,000 years, from the Mesolithic through to the early medieval period, with the majority being prehistoric.
Previous studies on footprints have tended to focus on discerning the size and composition of the group that left the tracks, as well as estimating their age and stature, but the sheer span of the Formby footprints has allowed researchers to delve even deeper, exploring the changing dynamics of how animals used this region over millennia.
In total, the tracks of 593 individual animals were identified, representing 401 large animals and 192 humans – making this one of the largest-known concentrations of predominately prehistoric faunal tracks in the world. As for the earliest deposits, dated to the Mesolithic, footprints from eight large mammal species have been identified from these beds, including humans, aurochs (a kind of now-extinct giant cattle), red deer, roe deer, wild boar, beaver, lynx, and wolf/dog. The oldest human footprints there have been dated to 8,600-8420 cal BP, making them the oldest post-glacial human footprints to have been found in the British Isles. Notably, between 8,600 and 8,000 cal BP there seems to have been a steady increase in both footprint density and in species diversity.
This biodiversity did not last long, however. By the Neolithic period, the number of human footprints markedly increased, while the footprints from other large animals became scarcer. In fact, from Neolithic contexts only two animal species – red deer and wolf/dog – have been identified. While the cause of this is unknown, the researchers theorise that ‘the observed decline in large mammals could be the result of several drivers, including habitat shrinkage following sea-level rise and the development of agricultural economies, as well as hunting pressures from a growing human population’.
In addition to the decrease in biodiversity seen over time, there was a notable difference in the pattern of human footprints. During the Mesolithic, it appears that people predominately walked northward along the mudflats, parallel with the coastline. By the time of the Neolithic, however, people appear to have mainly been walking to and from the sea. As the researchers theorise, ‘This may reflect the presence of more permanent settlements inland with journeys to fishing sites or moored vessels in the shallow waters at the edge of the saltmarshes.’
The full results of the study were recently published in Nature Ecology & Evolution (https://doi.org/10.1038/s41559-022-01856-2).