owed that about 106 ha of the total mire area, or 39%, is located within 60 m from ditches and therefore likely to be affected by past drainage activity. A larger proportion of productive mires, that is, mires with good grades, have been affected by ditches than less productive mires, mires with poor grades (Figure 6).
The 273 ha that made up the total mire area in 1880 had become reduced to 161 ha (59%) by 2013. The remainder is currently 106 ha forest (39%), 3.4 ha arable land (1.2%) and 2.7 ha water (1%) (Figure 3).
The various types of past management that we identified and quantified have affected essentially all of the ecosystem services provided by mires in the study area. The mires were used almost exclusively for haymaking starting in the late 1700s and ultimately reaching 22% in the late 1800s, after which they were abandoned and mostly left to slowly and passively recover. Thereafter, the effects of water regulation dominated—partly through dams that flooded some areas to enhance hay production and later extend the timber-floating season, but mostly through the use of drainage ditches to promote agriculture and later forest growth. Approximately 40% of the mires in our study area have permanently been converted to forest or arable land through drainage over the time frame of our study. These 300 years of management have legacy effects for the region’s biodiversity, water regulation, and carbon (C) sequestration (Elveland, 1983; Karlsen et al., 2016; Saarimaa et al., 2019).
At least two aspects of mire management have likely had mostly positive impacts on biodiversity: haymaking and seasonal flooding via damming. First, previous research has revealed that haymaking simplified the habitat structure, as all tussocks and shrubs were obstacles for scythes and the mires were therefore usually cleaned before the first harvest, after which the continual use kept the surface even (Zackrisson, 1976a). Trampling during harvest compacted the mire’s surface and generated wetter surface conditions, which favored the replacement of Sphagnum mosses with ‘brown mosses’ such as Drepanocladus, Scorpidium, and Campylium (Elveland, 1983; Moen, 1976). The shorter vegetation also allowed more sun to reach the ground surface. This allowed the low-statured, heliophytic plants such as Parnassia palustris and the currently red-listed Saxifraga hirculus to thrive (Elveland, 1983) and also favored several species of invertebrates (Sjöberg, 1982). Thanks to these effects, past haymaking is not considered a negative impact when wetlands are assessed according to the criteria for natural habitats of European interest in the sense of the EU Habitats Directive (Gardfjell and Hagner, 2016). On the contrary, continued or reintroduced harvest is recommended to preserve both ecological and cultural values of the last remaining mire meadows (Svensson and Moreau, 2012; Tenning, 2015). In our study area, however, no mires are currently used as meadows. In general, mire meadows in northern Sweden were abandoned in the 1920s and 1930s (Elveland, 1983), and this area probably followed the general pattern because the mires that were reclaimed as arable land in the early 1900s could produce much higher volumes of hay. When haymaking ceased, many of the abovementioned effects were reversed naturally. Sphagnum species came back to replace the brown mosses (Moen, 1976), tussocks formed, and bushes and trees started to colonize the area (Elveland, 1983). A manmade habitat of importance for biodiversity was thus lost.
Second, management through damming also affected the biodiversity of the mires in the region. In some cases dams such as the one at Renbergstjärnen in our study area were abandoned in the 1930s and thus, those mires have not since been subjected to annual flooding. In other locations, such as Bergtjärnen, the timber-floating dams were used until the 1960s, and later beavers (Castor fiber) moved in and sustained the flooding by building supplementary dams. As a result, these new water surfaces became important nesting habitats for ducks (Sjöberg, 