| 1. |
- Elliott, Sarah, et al.
(författare)
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The legacy of 1300 years of land use in Jamaica
- 2024
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Ingår i: Journal of Island & Coastal Archaeology. - : Taylor & Francis Group. - 1556-4894 .- 1556-1828. ; 19:2, s. 312-343
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Tidskriftsartikel (refereegranskat)abstract
- Despite decades of archaeological research on Jamaica, little is known about how settlers influenced landscape change on the island over time. Here, we examine the impact of human occupation through a multi-proxy approach using phytolith, charcoal, and stratigraphic analyses. White Marl was a continuously inhabited village settlement (ca. 1050-450 cal yrs BP) with large mounded midden areas, precolonial house structures, and human landscape management practices. We have shown that the local vegetation at White Marl was directly affected by human settlement through the use of agroforestry and burning, and suggest that fire was used to modify vegetation. Manioc phytoliths were found throughout human occupation and are broadly associated with increases in evidence for burning, suggesting fire was used to modify the landscape and clear vegetation for crop cultivation. The phytolith assemblages relate to three distinct temporal vegetation phases: (1) the earliest occupation dominated by arboreal vegetation (pre-ca. 870 cal yrs BP); (2) a transition to palm-dominated vegetation (ca. 870-670 cal yrs BP); and (3) the latest occupation representing European colonization associated with a more open, grass-dominated landscape (after ca. 670 cal yrs BP). These transitions occur independent of changes in paleoclimate records, suggesting humans were the dominant driver of vegetation change.
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| 2. |
- Kukla, Tyler, et al.
(författare)
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The resilience of Amazon tree cover to past and present drying
- 2021
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181. ; 202
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Tidskriftsartikel (refereegranskat)abstract
- The Amazon forest is increasingly vulnerable to dieback and encroachment of grasslands and agricultural fields. Threats to these forested ecosystems include drying, deforestation, and fire, but feedbacks among these make it difficult to determine their relative importance. Here, we reconstruct the central and western Amazon tree cover response to aridity and fire in the mid-Holocene—a time of less intensive human land use and markedly drier conditions than today—to assess the resilience of tree cover to drying and the strength of vegetation-climate feedbacks. We use pollen, charcoal, and speleothem oxygen isotope proxy data to show that Amazon tree cover in the mid-Holocene was resilient to drying in excess of the driest bias-corrected future precipitation projections. Experiments with a dynamic global vegetation model (LPJ-GUESS) suggest tree cover resilience may be owed to weak feedbacks that act to amplify tree cover loss with drying. We also compare these results to observational data and find that, under limited human interference, modern tree cover is likely similarly resilient to mid-Holocene levels of aridification. Our results suggest human-driven fire and deforestation likely pose a greater threat to the future of Amazon ecosystems than drying alone.
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