Palaeolimnological impacts of early prehistoric farming at Lough Dargan, County Sligo, Ireland Karen J. Taylor a, * , Aaron P. Potito a , David W. Beilman b , Beatrice Ghilardi a , Michael O’Connell a a Palaeoenvironmental Research Unit, School of Geographyand Archaeology, National University of Ireland Galway, Galway, Ireland b Department of Geography, University of Hawaii at Manoa, 445 Saunders Hall, 2424 Maile Way, Honolulu, HI 96822, USA article info Article history: Received 26 November 2012 Received in revised form 22 March 2013 Accepted 8 April 2013 Keywords: Geo-archaeology Palaeolimnology Chironomids Stable isotopes Neolithic Bronze Age Ireland abstract This study provides a unique method of inquiry for archaeological investigation with an aim to assess the intensity and effects of Neolithic and Bronze Age farming practices at Lough Dargan, northwest Ireland, through a multi-proxy analysis of a lake sediment core. Chironomid (non-biting midge fly) subfossils and lake sediment geochemistry (d 13 C, d 15 N and C:N ratios) were used to assess changes in limnological conditions through time. The limnological data were compared with macroscopic charcoal concentration and pollen data to examine the potential influence that early farmers had on a freshwater lake system within a prehistorically active catchment. Results from the chironomid analysis show that the first substantial period of agricultural activity in the early Neolithic (c. 3730e3190 BC) resulted in a temporary shift to more eutrophic lake conditions. There is evidence of animal husbandry with substantial levels of animal waste reaching the lake, leaving an imprint in the geochemical record of increased d 15 N values and decreased d 13 C values and C:N ratios during this time. The chironomid community reverted back to its pre-impacted state c. 3190 BC in response to a period of reduced farming (c. 3390e3000 BC) which eventually led to a distinct lull in activity, with possible cessation of farming from 3000 to 2700 BC. A return to eutrophic conditions coincided with the gradual return of agriculture, with more permanently altered lake conditions dominating from 2400 BC, even during a 250-year period of reduced human activity commencing at c. 1440 BC. Increased sedimentation rate, along with increases in d 13 C, d 15 N and C:N, the presence of chironomid taxa indicative of erosion, more eutrophic lake conditions and high concentrations of macroscopic charcoal all point to more intensive land use practices during the Bronze Age. Palaeolimnological data exhibited an immediate response to intensified farming during this time, and were especially responsive to pastoral farming due either to scale of activity or proximity to the lakeside. The success of this study demonstrates the effectiveness of palaeolimnological analysis in the investigation of prehistoric farming. This approach will help inform Neolithic and Bronze Age land-use practice and humaneenvironment relations in the region, and highlights the potential for chironomid-based archaeological research. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction At the beginning of the Neolithic in Ireland c. 4000 BC (all dates are quoted in calibrated years), Mesolithic societies based on fish- ing, gathering and hunting were replaced by farming-based econ- omies. Other substantial changes that occurred during the Neolithic include woodland clearances, more permanent settlement, a greater concern with territoriality, the construction of large communal ritual monuments and presumably also increased pop- ulation (Bogucki and Deborah, 2008; Cooney, 2000). The Bronze Age, which commenced at c. 2400 BC (O’Brien, 2004), saw an overall intensification of farming as society developed, with metalworking aiding the advancement (Grogan, 2005; Waddell, 2010). However, little is known about the intensity or environ- mental effects of prehistoric farming during the Neolithic and Bronze Age (c. 4000e600 BC). Present knowledge of early farming derives mainly from pollen and plant macrofossil investigations, which provide information on farming presence and human activity largely based on vegetation change. Macrofossil studies are usually site-specific and often * Corresponding author. National University of Ireland Galway, School of Geog- raphy and Archaeology, Palaeoenvironmental Research Unit, Room 116, Galway, Ireland. Tel.: þ353 (0)91 441537. E-mail addresses: k.taylor1@nuigalway.ie (K.J. Taylor), aaron.potito@ nuigalway.ie (A.P. Potito), beilman@hawaii.edu (D.W. Beilman), b.ghilardi1@ nuigalway.ie (B. Ghilardi), michael.oconnell@nuigalway.ie (M. O’Connell). Contents lists available at SciVerse ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas 0305-4403/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jas.2013.04.002 Journal of Archaeological Science 40 (2013) 3212e3221