Human encroachment, climate change and the loss of our archaeological organic cultural heritage: Accelerated bone deterioration at Ageröd, a revisited Scandinavian Mesolithic key-site in despair

Abstract

Ancient organic remains are essential for the reconstruction of past human lifeways and environments but are only preserved under particular conditions. Recent findings indicate that such conditions are becoming rarer and that archaeological sites with previously good preservation, are deteriorating. To investigate this, we returned to the well-known Swedish Mesolithic site Ageröd I. Here we present the result of the re-excavation and the osteological analyses of the bone remains from the 1940s, 1970s and 2019 excavation campaigns of the site, to document and quantify changes in bone preservation and relate them to variations in soil conditions and on-site topography. The results indicate that the bone material has suffered from accelerated deterioration during the last 75 years. This has led to heavily degraded remains in some areas and complete destruction in others. We conclude that while Ageröd can still be considered an important site, it has lost much of the properties that made it unique. If no actions are taken to secure its future preservation, the site will soon lose the organic remains that before modern encroachment and climate change had been preserved for 9000 years. Finally, because Ageröd has not been subjected to more or heavier encroachment than most other archaeological sites, our results also raise questions of the state of organic preservation in other areas and call for a broad examination of our most vulnerable hidden archaeological remains.

Quantifying archaeo-organic degradation – A multiproxy approach to understand the accelerated deterioration of the ancient organic cultural heritage at the Swedish Mesolithic site Ageröd

“…Comparative analyses were done on bone remains recovered on the 1940s and 1970s excavation of Ageröd [1]. The remains from these excavations are stored at LUHM under the deposition numbers LUHM 28977 and LUHM 80910 and are available at the museum upon request.…”

“…Lower right drawing of the Ageröd area by Arne Sjöström. Image freely available through CC by 4.0 licence by PLOS ONE and previously published in [1].…”

“…The 2019 re-investigation of Ageröd demonstrated that the bone remains at the site are threatened by accelerating destruction and that the previously best-preserved areas have now become the worst areas for bone preservation [1]. The excavation and zooarchaeological analysis of the osseous remains recovered on all three excavation campaigns (a total of 4240 bone fragments from Ageröd I were determined to family or species level and used in the study [1]) highlighted the problems of bone deterioration and showed that the osseous remains are suffering badly from accelerated degradation and revealed that in some areas this has destroyed the 9000-year-old bones, which only 75 years ago were well preserved. In an attempt to investigate the archaeo-organic preservation conditions, quantify the ongoing degradation and understand why the bones are rapidly deteriorating, a multiproxy approach to investigate different aspects of organic preservation and the soil properties related to the organic remains recovered at the 2019 re-excavation at the site is used.…”

“…By investigating the soil chemical properties and by relating them to bone histological analyses, collagen preservation and the palaeobotany at the site, questions of how organic preservation has changed during the last seven decades and what might have caused the changes are answered and discussed. The present study shall be viewed as a part of investigating the prerequisites for the future survival of our long-term archaeo-environmental archive of climatic and environmental changes and/or its relation to past human cultural interaction [2][3][4][5][6][7][8][9], in a time when reports of ongoing and accelerated destruction of this valuable record emerge from all over the world [1,[10][11][12][13][14][15][16][17][18][19][20][21][22]. settlements where section A, C and HC intersect one settlement and Ageröd I:B and I:D intersects two others [25].…”

“…settlements where section A, C and HC intersect one settlement and Ageröd I:B and I:D intersects two others [25]. For more detailed information about the site see [1].…”