We produced an integrated history of terrestrial and lake ecosystems from a high-resolution stratigraphy from Lake Lucone, a small, closed lake, in the Prealps of northern Italy, which is characterized by predominantly endogenic, biologically controlled sedimentation covering the last 5500 years. Our analytic approach combines ordination techniques with time series analysis to detect correlated changes among microbotanical variables (upland and aquatic pollen, algae, cyanobacteria, dung spores, microcharcoal particles), sedimentary proxies (LOI steps, calcimetry, FTIR spectrometry) and main nutrients, which are stable under waterlogged conditions (Pinorg, Porg, K). The impact of the Bronze Age pile dwelling is recorded by massive effects on terrestrial ecosystems, lake sedimentation, and nutrient influx. Forest conditions and lake sedimentation returned to semi-natural baseline at the end of the 700-year long phase of Early to Middle Bronze Age settlement, but lake-side forests did not fully recover, and further changes on landscape composition occurred from the Iron Age onwards. Time series correlation of micro-botanical proxies and P forms have enabled to detect different patterns of human impact, and the contrast of internal and external P sourcing. During the dwelling phase intensive P mineralization, produced by fireplaces triggered Pinorg sinking. Pinorg was promptly immobilized by calcite absorption, thus preventing blooms of green algae and cyanobacteria. Analyzing waste disposals, we could also distinguish domestic hearth production from a contribution by animal husbandry, the latter marked by Porg increase. External sourcing was prompted by farming and cropping in the lake catchment. The observed changes, in littoral sedimentation and biological proxies in the 5500-years long sequence, are primarily affected by human impact. Lake Lucone represents a key site, since it documents interactions between bronze Age settlements and related ecological impacts on both terrestrial environment and lacustrine sedimentation, as recorded in a continuous sequence, as well as the end of Bronze Age pile dwelling culture.
The impact of Early to Middle Bronze Age settlements and farming on vegetation, ecology, nutrient flux and sedimentation at Lake Lucone, northern Italy
Giulia Furlanetto;Renata Perego;Cesare Ravazzi
2023
Abstract
We produced an integrated history of terrestrial and lake ecosystems from a high-resolution stratigraphy from Lake Lucone, a small, closed lake, in the Prealps of northern Italy, which is characterized by predominantly endogenic, biologically controlled sedimentation covering the last 5500 years. Our analytic approach combines ordination techniques with time series analysis to detect correlated changes among microbotanical variables (upland and aquatic pollen, algae, cyanobacteria, dung spores, microcharcoal particles), sedimentary proxies (LOI steps, calcimetry, FTIR spectrometry) and main nutrients, which are stable under waterlogged conditions (Pinorg, Porg, K). The impact of the Bronze Age pile dwelling is recorded by massive effects on terrestrial ecosystems, lake sedimentation, and nutrient influx. Forest conditions and lake sedimentation returned to semi-natural baseline at the end of the 700-year long phase of Early to Middle Bronze Age settlement, but lake-side forests did not fully recover, and further changes on landscape composition occurred from the Iron Age onwards. Time series correlation of micro-botanical proxies and P forms have enabled to detect different patterns of human impact, and the contrast of internal and external P sourcing. During the dwelling phase intensive P mineralization, produced by fireplaces triggered Pinorg sinking. Pinorg was promptly immobilized by calcite absorption, thus preventing blooms of green algae and cyanobacteria. Analyzing waste disposals, we could also distinguish domestic hearth production from a contribution by animal husbandry, the latter marked by Porg increase. External sourcing was prompted by farming and cropping in the lake catchment. The observed changes, in littoral sedimentation and biological proxies in the 5500-years long sequence, are primarily affected by human impact. Lake Lucone represents a key site, since it documents interactions between bronze Age settlements and related ecological impacts on both terrestrial environment and lacustrine sedimentation, as recorded in a continuous sequence, as well as the end of Bronze Age pile dwelling culture.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
