The combined effects of climate change and nutrient availability on Arctic vegetation growth are poorly understood. Archaeological sites in the Arctic could represent unique nutrient hotspots for studying the long-term effect of nutrient enrichment. In this study, we analysed a time-series of ring widths of Salix glauca L. collected at nine archaeological sites and in their natural surroundings along a climate gradient in the Nuuk fjord region, Southwest Greenland, stretching from the edge of the Greenlandic Ice Sheet in the east to the open sea in the west. We assessed the temperature-growth relationship for the last four decades distinguishing between soils with past anthropogenic nutrient enrichment (PANE) and without (controls). Along the East–West gradient, the inner fjord sites showed a stronger temperature signal compared to the outermost ones. Individuals growing in PANE soils had wider ring widths than individuals growing in the control soils and a stronger climate-growth relation, especially in the inner fjord sites. Thereby, the individuals growing on the archaeological sites seem to have benefited more from the climate warming in recent decades. Our results suggest that higher nutrient availability due to past human activities plays a role in Arctic vegetation growth and should be considered when assessing both the future impact of plants on archaeological sites and the general greening in landscapes with contrasting nutrient availability.

This file includes the data used to analyse: i) time series of mean ring width of Salix glauca L. and climate from the nine archaeological sites (PANE) and in their natural surroundings (CONT) in Nuuk Fjord (West Greenland); ii) climate-growth relationship and the effect of nutrient availability; iii) climate and nutrient sensitivity accounting for the effect of insect outbreaks and their carry-over effects (Supplementary Information). In particular, time series of raw and standardized ring width (RW and Z-score), mean temperature of June-August and the average sum of thawing (TDD) and growing degree days (GDD) for all the PANE and CONT sites. Variables are organized in columns and named with the acronyms described in Table 1, Table 2. and Figure 2-5.