Historic hay cutting dates from Sweden 1873–1951 and their implications for conservation management of species-rich meadows Ove Eriksson a,⇑ , Kjell Bolmgren a,b , Anna Westin c , Tommy Lennartsson c a Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden b Swedish National Phenology Network, Unit for Field-based Forest Research, Swedish University of Agricultural Sciences, SE-360 30 Lammhult, Sweden c Swedish Biodiversity Centre, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden article info Article history: Received 20 October 2014 Received in revised form 18 December 2014 Accepted 12 January 2015 Keywords: Flowering phenology Mowing dates Land use history Leaf burst phenology Semi-natural hay-meadows abstract Semi-natural hay meadows are species rich habitats, formed by a long history of management and they have experienced a drastic decline all over Europe. There is a vast literature on conservation and species diversity of semi-natural hay-meadows, but very limited information on historic timing of hay cutting. We analyzed data collected between 1873 and 1951 on hay cutting dates and phenology of six plant spe- cies from farms distributed across Sweden. The data set comprised 16,015 observations from 175 sites. Results show that date of start and end of hay cutting varied across Sweden. The start of hay cutting was generally delayed by 2.2 days per latitudinal degree and 1.5 days per 100 m altitude, while the end of hay cutting was generally delayed by 2.9 days per latitudinal degree and 2.5 days per 100 m altitude. The average hay cutting period was 18.5 ± 6.6 days, and became slightly shorter northwards. Site-specific factors had a great impact on when hay cutting was performed, as indicated by a significant correlation between flowering (and leafing) phenology in other species and start date of hay cutting. Today, management for conservation is usually related to a calendar date (e.g. regulated in eligibility cri- teria and requirements for payment in agri-environment programs in EU). In order to mimic historic management that formed this habitat, management should instead account for latitude and altitude, between-year variation in timing of hay cutting, variation in both start and end dates of hay cutting and if possible local phenological conditions. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The landscapes of Europe have changed considerably during the last century, and many habitats associated with management regimes no longer in use have consequently become rare. One type of habitats that has experienced a particularly drastic decline is traditionally managed semi-natural hay-meadows (Emanuelsson, 2009; Eriksson and Cousins, 2014). These meadows, here loosely defined as open or moderately wooded areas made up of semi- natural vegetation and used for production of winter fodder, often harbor exceptional species diversity (Veen et al., 2009), not only of plants but also of other organisms such as insects, mollusks and birds. Accordingly, species diversity and management of semi- natural hay-meadows have received a considerable attention across Europe. Examples include studies from Austria (e.g. Zechmeister et al., 2003), the Czech Republic (e.g. Dolezal et al., 2011), Estonia (e.g. Kull and Zobel, 1991), Finland (e.g. Hellström et al., 2009), Germany (e.g. Krause et al., 2011), Italy (e.g. Marini et al., 2008), Norway (e.g. Myklestad and Sætersdal, 2004), Poland (e.g. Falin ´ ska, 2003), Romania (e.g. Turtureanu et al., 2013), Spain (e.g. Prince et al., 2012), Sweden (e.g. Dahlström et al., 2008), Switzerland (e.g. Fischer and Stöcklin, 1997) and UK (e.g. Critchley et al., 2007). Hay making, i.e. harvest of winter fodder, but also intentional management to improve hay production, has a long history in Eur- ope, most likely dating back to the Iron Age, i.e. at least some cen- turies BCE (Hodgson et al., 1999; Emanuelsson, 2009; Pedersen and Widgren, 2011; Eriksson, 2013). Hay-making was associated with the mixed farming system that dominated in a wide belt across the northern part of Europe, based on winter-stabling of livestock, harvesting of winter fodder, summer grazing and manure-fertil- ized permanent cultivations (Grigg, 1974; Pedersen and Widgren, 2011). For people in northern Europe, and for people living at high http://dx.doi.org/10.1016/j.biocon.2015.01.012 0006-3207/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: ove.eriksson@su.se (O. Eriksson), kjell.bolmgren@slu.se (K. Bolmgren), anna.westin@slu.se (A. Westin), tommy.lennartsson@slu.se (T. Lennartsson). Biological Conservation 184 (2015) 100–107 Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon