d predominantly for wetland habitats, where there could be some trees but not closed forest (Svenska Akademien, 2020). An analysis of the wetland terminology of a group of dialects of northern Sweden supports this definition (Wiklund, 1992: 97–99). In future studies, one should explore how the term ‘myr’ has been applied in Swedish land surveys over time and across Sweden. In this study, we base the definition on the current interpretation of the word and our own experiences of the maps and aerial photos that we have studied, concluding that what was called ‘myr’ in 1880 and today is essentially the same.
Another crucial concept of our study is the total mire area, which we used to calculate the proportions of mire managed for different purposes. Defining the total mire area as the sum of all mire meadows, peat pits and unused mires indicated on the enclosure map from 1880, is likely a conservative estimate of what occurred before mire management began. Indeed, mires mapped in 1880 could exclude mires that once existed but that had been converted to other land classes earlier. However, when we checked all available historical maps from both Abborrtjärn and surrounding villages, we did not find any indications of such changes. In 1880, all cultivated fields of the study area were located close to the farmsteads on sandy soils with varying proportions of clay, according to the map tables, and thus not on peatland. Unlike Strandin Pers (2012), who was able to detect fields that once had been mires from their names, ending in ‘fen’ (sw. ‘-kärr’) or ‘bog’ (sw. ‘-mosse’), we found no such cases on the maps of Abborrtjärn, neither in 1805 nor 1880.
Another land class that could potentially have included mires in 1880 is ‘land suitable for cultivation’ (sw. ‘odlingsmark’), but in our study area, those areas were mostly located next to existing fields on sandy soils. Other kinds of land use were indicated on the 1880 map, such as ‘gravel pits’, but they were unlikely to have affected any mires. In other words, although we may have misclassified small areas, we believe that the sum of the land classes ‘mires’, ‘mire meadows’, and ‘peat pits’, as we have defined them from the enclosure map of 1880, gives the best possible representation of the total mire area as it was before any intensive human intervention began in the study area.
We have identified the various types of historical land use in mires, quantified the proportion of mires concerned, established a timeline of impact, and discussed possible legacy effects, in particular with respect to climate change. We have shown that the former use of mires can be mapped in detail through an interdisciplinary analysis involving sources and methods ranging from historical maps to state-of-the-art remote-sensing analysis. Our mapping shows that although mires have not been subjected to any active use for more than 30 years, legacy effects are still substantial, most importantly through the conversion of mires into forest. In addition, many open mires continue to change, due to both previous ditching and the abandonment of management. Therefore, it can be difficult to separate these two factors and predict how mire habitats will develop in the future. Such factors should be taken into account to achieve a predictable outcome of mire management aimed at the improvement of important ecosystem services such as biodiversity, water regulation, and carbon sequestration.
The authors are grateful to the two anonymous reviewers for their many useful comments on the manuscript.
The research was supported by SITES funded by the Swedish Research Council and FORMAS grants to Eliza Maher Hasselquist and Hjalmar Laudon.
The authors have no competing interests to declare.
GN designed the study, and digitized and processed the data. The results were discussed and analyzed jointly by all authors, and conclusions were drafted during these discussions. GN and EMH wrote the manuscript with important contributions from HJ.
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