Erosion rate response to mining and deforestation, Elba Island

Throughout history, humans have modified the landscape by farming, extracting natural resources, and deforestation. However, it is not fully understood to what extent such activities have changed vegetation structures and potentially caused accelerated soil erosion. In this study, we investigate the effects of human activities on vegetation and erosion rate changes on the island of Elba, Italy. Previous geoarchaeological studies succeeded in reconstructing human-environmental interaction in the past and providing an independent reference frame for the current study. Hence, we hypothesize that intense iron production on Elba since the 6th century BCE, first by Etruscans, and later by Romans, was accompanied by deforestation and thereby caused increased soil erosion. To test our hypothesis, we collected sediment samples from modern streams and from existing floodplain sediment cores to reconstruct the millennial-scale and more recent changes in landscape-scale erosion rates, and in vegetation and hydrology by means of leaf wax isotopes (d²H, d¹³C). We use in situ cosmogenic ¹⁰Be and ¹⁴C produced in quartz to obtain erosion rates. The different half-life of these two nuclides (~1.4 Myr for ¹⁰Be and ~5.7 kyr for ¹⁴C) makes them sensitive to changes in erosion rates that occur on human time scales. ¹⁰Be results indicate relatively uniform millennial-scale erosion rates on the order of 0.04 mm/yr across the eastern part of the island, where we collected most of the samples. We expect that the combination of these methods will reveal the impact and patterns of human-induced soil erosion in Elba.