Mapping the ecological resilience of Atlantic postglacial heathlands

Abstract

Anthropogenic heathlands are semi‐natural ecosystems with a unique cultural and biodiversity value, considered worthy of preservation across most of the world. Their rate of loss, however, is alarming. Currently, we know little about the heathlands' actual span of resilience affordances and their association with abiotic and anthropogenic factors, including how much additional intervention they need to persist. Consequently, we are missing out on vital knowledge for conservation, management and the historical persistence of heathlands. This paper develops a method to assess the ecological resilience affordances of Atlantic postglacial heaths in the absence of human management. We use 12 existing cases of heathland succession to establish a four‐step resilience grade for each site, which we regress onto a series of explaining factors and use it in predicting heath resilience across postglacial Atlantic Northern Europe. We find that temperature, humidity, elevation and sandiness have a positive correlation with high heathland resilience. Our predictive mapping shows an uneven distribution of ecological heath resilience across Atlantic Northern Europe within an area of 1,000 × 1,200 km of 5 × 5 km resolution. Historic heathland distributions far exceed areas that afford high heath resilience, suggesting that heath distribution and persistence depend on both abiotic and anthropogenic factors. Policy implications: The map predicting the ecological resilience of Atlantic postglacial heaths can be used by managers working towards heath preservation and restoration to prioritize conservation efforts and to plan management practices across Atlantic Northern Europe. Together with the predictive model, it provides an important initial screening tool to assess heathland resilience in the absence of management as well as the impact of atmospheric nitrogen. The results are equally relevant for scholars who are interested in humans' role in increasing and decreasing ecosystem resilience. Our predictive method can be applied in other regions across the world by adding regionally specific variables.

Anthropogenic Heathlands in Prehistoric Atlantic Europe: Review and Future Prospects

“…In south-western Norway, coastal heathland dominated by Calluna vulgaris may cover lower-altitude areas, gradually merging into inland heath or higher-altitude, rocky landscapes around fjords. The species turnover rate of the heathlands ranges from Calluna vulgaris degeneration and forest encroachment within twenty years to the persistence of heathlands for a century or more (Løvschal & Damgaard, 2022). The dry inland heaths provide grazing opportunities for livestock, especially in the first five years of heather growth, as well as fuel and fodder.…”

Ancestral commons: the deep-time emergence of Bronze Age pastoral mobility

“…These cycles would have been linked to the ancestors through oral narratives as well as made tangible in the physical and visual qualities of funerary monuments. Moreover, the persistence of the heathlands would have constituted a stable landscape to which people could return, one distinct from other landscapes (Løvschal 2022).…”

“…In some regions, such as Jutland, the resulting open landscapes eventually extended across more than 40 per cent of the territory. These new landscapes were inherently unstable, however, and grazing and managed burning were required to maintain them, with some areas oscillating between pasture and forest (Odgaard 1994; Løvschal & Damgaard 2022). Yet, over the longer term, the emergence of this new type of landscape afforded later prehistoric societies significant social and economic opportunities.…”

Changing species dominance patterns of Boreal‐Arctic heathlands: evidence of biotic homogenization

“…These empirical findings suggest, contrary to expectations of evergreen dwarf shrub vulnerability to climate change (Bokhorst et al 2015), that native evergreen dwarf shrub species are responsive to climate warming (Vowles and Björk 2019), and that there is an evergreening rather than greening in Arctic and Boreal heathland systems. Also, the succession into forests is considered a current threat to treeless Boreal heathland systems in Norway (Hovstad et al 2018) and to Atlantic Calluna vulgaris ‐dominated heathlands across northern Europe (Løvschal and Damgaard 2022). Tree or larger shrub encroachment into treeless heath may, however, depend on the abundance of E. nigrum ; no tree or larger shrub encroachment was found in E. nigrum ‐dominated heathlands in Finland (Maliniemi et al 2018) nor in Atlantic C. vulgaris ‐dominated heathlands where E. nigrum was common (Løvschal and Damgaard 2022).…”

“…Also, the succession into forests is considered a current threat to treeless Boreal heathland systems in Norway (Hovstad et al 2018) and to Atlantic Calluna vulgaris ‐dominated heathlands across northern Europe (Løvschal and Damgaard 2022). Tree or larger shrub encroachment into treeless heath may, however, depend on the abundance of E. nigrum ; no tree or larger shrub encroachment was found in E. nigrum ‐dominated heathlands in Finland (Maliniemi et al 2018) nor in Atlantic C. vulgaris ‐dominated heathlands where E. nigrum was common (Løvschal and Damgaard 2022). Furthermore, after adding 500 birch seeds to a dwarf shrub heathland in the forest ecotone, Vuorinen et al (2017) found only two surviving birch seedlings.…”