An approach to modelling the impact of prehistoric farming on Holocene landscape phosphorus dynamics

Abstract

The lake sediment phosphorus (P) record at Hatch Mere (Cheshire, UK) is investigated to assess the role of human activity in modifying Holocene landscape P export dynamics, and to develop an approach to incorporating this effect into a pre-existing long-term, large-scale landscape model of natural P export. Analysis of the lake sediment record shows that the catchment P yield is low and constant prior to ca. 6000 BP, but then increases up to the present day. This increase occurs in steps that coincide with the Neolithic, Bronze Age and Medieval periods, and the first half of the 20th century, consistent with an anthropogenic cause. Such an interpretation is supported by close correlation of the P export flux with the estimated regional population density. We demonstrate that the effect of human activity on landscape P dynamics can be incorporated into the existing P export model by scaling the soil secondary P leakage rate coefficient to population density. The findings of this study suggest that lake sediment P accumulation rate data may provide a novel method for estimating prehistoric local population density. Additionally, we show that the pre-Neolithic landscape P export was low, and we reject the widely held view that Hatch Mere is naturally eutrophic.

The geomorphology of the Anthropocene: emergence, status and implications

“…Ever since Gilbert's () pioneering studies, geomorphologists have used mining‐impacted rivers as an outdoor laboratory for studying the major, commonly abrupt, changes to channel form resulting from sediment supply increases, including in California (James, ; Singer et al , ) and Australia (Pickup et al , ; Knighton, ; Erskine and Saynor, ). Lakes within fluvial catchments affected by mining also may preserve evidence of increases in sediment flux and contaminant delivery (Boyle et al , ). A range of other human activities such as irrigation and navigation also can result in profound changes to fluvial processes and forms, particularly through radically altering channel‐floodplain connectivity.…”

Assessing the response of micro-eukaryotic diversity to the Great Acceleration using lake sedimentary DNA

“…Their ecological functioning, the biodiversity they host and the ecosystem services they provide are threatened by water pollution, resource exploitation, degradation of habitats, and climate change effects among other stressors 1 – 3 . Anthropogenic activities have impacted lakes for millennia 4 , 5 , but pressures have largely increased in magnitude since the mid-twentieth century, i.e., The Great Acceleration 6 , 7 . The second part of the twentieth century is unambiguously a time of major and multiple threats that might have disproportionately affected lake biodiversity and associated ecological functions (e.g., nutrient recycling, efficiency of trophic transfer, and quality of fish production) 3 , 8 .…”

A Holocene high‐resolution record of aquatic productivity, seasonal anoxia and meromixis from varved sediments of Lake Łazduny, North‐Eastern Poland: insight from a novel multi‐proxy approach

“…According to Wacnik (2009), the entire area was covered with pine-birch forests already in the Allerød Interstadial and, since~10 200 cal a BP, deciduous forests composed of elm (Ulmus) and hazel have formed (e.g. Wacnik, 2009;Karpińska-Kołaczek et al 2014), suggesting that the nutrient pools in the catchment were already well developed (Boyle et al, 2015) at the time of lake formation. Temperatures were generally warm in the Holocene with a maximum between~9000 and 5000 cal a BP (Heikkilä & Seppä, 2010, Fig.…”