Heathlands are unique cultural landscapes that once existed across vast stretches of northern Europe. Their deep-time persistence has formed an intrinsic part of economic and cultural practices. Such a complex interaction requires interdisciplinary approaches, including archaeology, across multiple regions to fully grasp all its aspects. The authors of this article review how research has been conducted in prehistoric heathlands across six nations in north-western Europe and outline the heaths’ general characteristics. They discuss the major issues in that research, namely recurring narratives derived from history, an overall absence of consideration of the cultural aspects of heathlands, and a paucity of cross-regional initiatives. They suggest a series of theoretical and methodological approaches to improve this situation across expanded geographical and temporal scales.

Two species, Cliostomum coppinsii Fryday & Kantvilas sp. nov. from Scotland, and Cliostomum praepallidum (Müll. Arg.) Kantvilas & Fryday comb. nov. from Tasmania and southern South America, are described, illustrated and discussed. Both occupy an unusual position within the genus on account of their atypically wide, ± polarilocular ascospores. Patellaria banksiae Müll. Arg., based on a collection from Australia, is lectotypified and reduced to synonymy with Cliostomum griffithii (Sm.) Coppins.

The relationship between Calluna vulgaris seedbank density and climate was investigated using regression analysis and two related techniques (factor-ceiling analysis). The seedbank data originated from published and unpublished studies. Low seedbank densities were associated with sites in the relatively dry, sunny and warm south and east of Great Britain. However, as the climatic variables used in the study were highly intercorrelated, it was not possible to determine which climatic variable had the greatest influence on seedbank density. A hypothesis is described suggesting that the limits of seedbank density can be described for single environmental factors. The operation of other environmental and management factors may reduce the seedbank density to less than this maximum. This is illustrated for a range of climatic variables using factor-ceiling analysis. The processes following seed deposition and the longevity of seeds in the soil are highlighted as possible factors controlled by climate which determine seedbank density.

Mature heather (Calluna vulgaris) and bracken (Pteridium aquilinum) turfs, transplanted from the field, were subjected to factorially combined experimental treatments for three consecutive years. Summer drought had the greatest effect, decreasing photosynthesis, growth and reproductive output in both species, and opening the bracken canopy. The timing of the drought relative to plant development was critical to which species was worst affected; bracken was worst affected by an early drought, heather by a later drought. Both species showed physiological damage during drought but, as predicted on the basis of their functional types, heather showed greater acclimation of water-use efficiency to drought stress. Contrary to expectations based on functional types, heather responded more rapidly than bracken to increased nitrogen supply (50 kg N ha−1 yr−1). Added nitrogen caused both species to start above-ground growth earlier in the spring. For bracken this stimulation was short- lived; added nitrogen might be preferentially allocated to the rhizome and the longer-term consequences of this are unknown. For heather, nitrogen promoted growth and flowering throughout the season. There was no positive effect on the photosynthetic physiology of either species; changes in resource partitioning, and thus photosynthate production at the canopy level, are the most likely mechanism for the increase in heather shoot growth. Warmer temperatures increased heather shoot growth from early spring onwards but did not advance bracken crozier emergence, although frond height and the proportion of fertile fronds were subsequently increased. No significant effects of warming on the photosynthetic physiology of either species were found. Predictions of responses of heather and bracken to environmental change are complicated by the strong interactive effects of unpredictable climatic events such as drought and extreme winter temperatures. When drought was imposed, damage to heather was much greater in plants receiving increased nitrogen supply. Stimulation of growth by nitrogen resulted in a water demand that was unsustainable in drought conditions, leading to wilting, reduced shoot growth and some acclimation of water-use efficiency. Additionally, a very cold winter spell proved most damaging to heather that had been droughted in the previous summer. For bracken, winter damage occurred in plants that had been warmed, with significantly fewer fronds emerging in the next spring and thus canopy photosynthetic potential being reduced. We predict that positively managed heather has the potential to limit the bracken problem in conditions of environmental change, provided that high levels of nitrogen deposition do not coincide with increased drought frequency.

Regular (monthly) additions of NH4NO3 (4–12 g N m−2 yr−1) were made over a period of 8 yr (1989–98) to areas of moorland in North Wales dominated by the ericaceous shrub Calluna vulgaris. Results from the early stages of the experiment (1990–94) have shown marked and dose-related increases in shoot extension and canopy height in response to the nitrogen treatments, with significantly higher shoot nitrogen contents. The nitrogen-related stimulation in the growth of the C. vulgaris canopy over this period has resulted in large accumulations of litter on the high-nitrogen-treated plots (6.6 kg m−2 in plots treated with 12 g N m−2 yr−1, compared with 3.8 kg m−2 for the water controls). Litter nitrogen concentrations were also significantly increased at the higher rates of nitrogen addition, leading to a doubling of the total return of nitrogen to the litter layer over the experimental period. These changes in vegetation structure were associated with large reductions in the abundance of the bryophyte and lichen species normally present under the untreated canopy. Results since 1994, however, show little increase in shoot extension in response to the nitrogen treatments, with no clear dose response to increasing levels of addition. These findings are associated with a dose-related increase in the susceptibility of the nitrogen-treated areas of the C. vulgaris canopy to late winter injury, characterized as browning of the shoot tips in early to late spring. These results indicate that deleterious effects are now accumulating as a result of the long-term addition of nitrogen to these moorland plots.

Bracken (Pteridium aquilinum (L.) Kuhn) and heather (Calluna vulgaris (L.) Hull) are important upland species which often grow in close proximity in the UK. The effects of factorial treatments of elevated atmospheric CO2 (539 μmol mol−1 as opposed to ambient atmospheric CO2 concentrations of 355 μmol mol−1), added N (50 kg N ha−1 as NH4NO3) and added P (20 kg P ha−1 as NaH2PO4) on the performance of these two species were studied under controlled environmental conditions using container-grown plants. Plants grown and measured at high CO2 had higher rates of net photosynthesis than those grown and measured in ambient CO2 . This increase was greater in heather than in bracken and resulted in a large stimulation of growth in the former. In bracken there was no significant change in plant size or phenology. The increase in biomass of heather in high CO2 was greatest in the absence of added nutrients and lowest when both N and P were supplied. The growth and photosynthesis of both plants responded positively to the supply of P alone or P with N (in both CO2 atmospheres), but there was little response to N alone. The implications of these findings for bracken and heather growing in the field under conditions of an elevated CO2 atmosphere and greater nutrient availability are discussed.