Molinia Research Articles

Mechanochemical extraction of edible proteins from moor grass.

Extracting edible nutrient-rich food fractions from unconventional sources, such as grass, could play a pivotal role in ensuring food security, bolstering economic prosperity, combating climate change, and enhancing overall quality of life. Current extraction techniques rely heavily on harsh chemicals, which not only degrade nutrients but can also substantially add to the cost of the process and make downstream separation challenging. In this study, we harnessed a mechanochemical process, liquid-assisted grinding (LAG) with and without Na2CO3, termed sodium carbonate assisted grinding (SAG), to extract the protein fraction from moor grass. These techniques were compared to the conventional alkaline extraction (AE) method. Unlike alkaline extraction, which solubilized over 70% of the material, the mechanochemical approach using Na2CO3 solubilized only 55% of the grass while still extracting the vast majority of the protein in the original grass feedstock. The protein fractions obtained from the SAG process had a similar amino acid profile to the core feedstock but also contained distinct characteristics over the other methods of extraction. FT-IR analysis, for example, identified the presence of an amide III band in the protein fractions obtained from the SAG process, indicating unique structural features that contribute to improved dispersibility, gelation properties, and water-in-water stability. Furthermore, the extracted moor grass protein contained a higher proportion of glutamic acid in comparison to other amino acids in the protein, which indicates a savoury umami (meaty) characteristic to the protein fraction. The protein extracted via SAG also exhibited good heat stability (139-214 °C), rendering them potentially suitable for baking applications. Additionally, coupling Na2CO3 with liquid assisted grinding not only removed the need for organic solvents and conventional heating but also reduced solvent consumption by 83%, compared with the typical alkaline extraction, thus simplifying the downstream processes necessary to produce food fractions. This study demonstrates the potential significance of mechanochemical extraction processes in unlocking nutrients from unconventional resources like grass, to produce the next generation of sustainable food ingredients.

Molinia caerulea alters forest Quercus petraea seedling growth through reduced mycorrhization.

Oak regeneration is jeopardized by purple moor grass, a well-known competitive perennial grass in the temperate forests of Western Europe. Below-ground interactions regarding resource acquisition and interference have been demonstrated and have led to new questions about the negative impact of purple moor grass on ectomycorrhizal colonization. The objective was to examine the effects of moor grass on root system size and ectomycorrhization rate of oak seedlings as well as consequences on nitrogen (N) content in oak and soil. Oak seedlings and moor grass tufts were planted together or separately in pots under semi-controlled conditions (irrigated and natural light) and harvested 1 year after planting. Biomass, N content in shoot and root in oak and moor grass as well as number of lateral roots and ectomycorrhizal rate in oak were measured. Biomass in both oak shoot and root was reduced when planting with moor grass. Concurrently, oak lateral roots number and ectomycorrhization rate decreased, along with a reduction in N content in mixed-grown oak. An interference mechanism of moor grass is affecting oak seedlings performance through reduction in oak lateral roots number and its ectomycorrhization, observed in conjunction with a lower growth and N content in oak. By altering both oak roots and mycorrhizas, moor grass appears to be a species with a high allelopathic potential. More broadly, these results show the complexity of interspecific interactions that involve various ecological processes involving the soil microbial community and need to be explored in situ.

Diversification of Molinia‐dominated blanket bogs using Sphagnum propagules

Abstract Increasing dominance by purple moor grass, Molinia caerulea (‘Molinia’) on globally rare and protected blanket bogs of the United Kingdom and the South Pennines is a growing threat to diversity and carbon storage, as well as increasing the risk of wildfire. In a trial to increase diversity using Sphagnum plugs planted on three Molinia‐dominated sites in the South Pennines, an initial rapid increase in cover of plug‐derived Sphagnum (PDS) suggested an advantage over that of naturally occurring Sphagnum colonies, the latter remaining below 1% cover throughout; subsequent plateauing of PDS cover in areas of moderate Molinia cover (<80%) was linked with drought stress, whereas declining cover in Molinia‐dense areas (>80%) suggested additional competition for light. The cover of Molinia was only weakly reduced by, and then completely recovered from, a baseline flailing treatment. Increasing cover of PDS in all of the treatments had no clear effect on the cover of Molinia. The cover of naturally occurring indicator species was strongly reduced by the baseline flailing treatment; subsequent recovery was not complete, even with contributions by PDS. There was a negative linear relationship between Molinia cover and indicator species cover, over all ranges of Molinia cover. Water table depths were lowered by PDS during the first 3 years of the trial, perhaps due to facilitated capillary conduction of water through the buried plug tissues. It was concluded that PDS can establish rapidly amongst Molinia, boosting the diversity and cover of indicator species, but that establishment is slower in areas of dense Molinia and also likely to be hampered by periods of severe drought stress. Prior flailing had no clear benefit on the growth of PDS but reduced the cover of naturally occurring indicator species. Further investigations should include the role of water stress, shading and phosphorus limitation in restricting the growth of PDS within Molinia‐dominated swards.

The herbicide cycloxydim is an effective alternative to propyzamide or glyphosate for the control of the forest grass weeds Molinia caerulea, Calamagrostis epigejos, Deschampsia flexuosa and Holcus lanatus

Abstract We tested the efficacy of a range of herbicides to see if they might be potential substitutes for the use of propyzamide or glyphosate to control grass weed species that, if left unchecked, often outcompete recently planted trees in UK forests. Applications of 0.45kg a.i. ha−1 cycloxydim in late April–early May gave good control of wood small reed (Calamagrostis epigejos (L.) Roth), Yorkshire fog (Holcus lanatus L.), and wavy hair grass (Deschampsia flexuosa (L.) Trin.)) for at least 12 weeks after application. When coupled with a sequential application of 0.15kg a.i. ha−1 propaquizafop made 5 weeks later, purple moor grass (Molinia caerulea (L.) Moench) was controlled for at least 21 weeks. Sequential applications of 0.45 kg a.i. ha−1 cycloxydim in October, then 0.45 kg a.i. ha−1 cycloxydim in late April, was the most effective treatment for minimizing competition from purple moor grass, wood small reed or wavy hair grass and equally effective as propyzamide on Yorkshire fog. The herbicides carbetamide, clethodim, clodinafop-propargyl and fenoxaprop-p-ethyl were not as effective as cycloxydim. We conclude that cycloxydim is effective on a broader range of grass weeds than previously thought. Cycloxydim and propaquizafop are both highly selective and unlike the broad-spectrum herbicide glyphosate will not harm young trees, even if they are oversprayed when in active growth. If applied at the correct time of year, cycloxydim is likely to be as effective as glyphosate on most grasses, and for wood small reed, purple moor grass and wavy hair grass considerably more effective than propyzamide. A sequential application of cycloxydim or possibly propaquizafop in the autumn, followed by a second spray in late April of the following spring, is likely to be the most effective means of maximizing tree growth and survival in grass dominated new planting or restock sites in UK forests.

Investigating the role of root exudates in the interaction between oak seedlings and purple moor grass in temperate forest

Oak regeneration in temperate forests often fails in the presence of understorey grass. Competition by resource exploitation between plants has been extensively studied. By contrast, competition by interference, especially chemical interference (allelopathy), has been much less thoroughly examined and its relative importance remains unclear. We investigated the influence of allelopathic interaction on plant performance (biomass production) in a pot experiment with sessile oak (Quercus petraea) and purple moor grass (Molinia caerulea), either sole- or mixed-grown. Plants were watered with either Quercus root exudates or Molinia root exudates. After 6 months of growth, oak biomass increment was significantly lowered by Molinia root exudates. The oak’s root system was more strongly affected than its aerial part. Quercus root exudates favoured oak growth but did not affect moor grass. Conversely, Molinia root exudates had a small depressive effect on its own growth, but its biomass was favoured by the presence of oak grown in the same pot. Resource exploitation had a more detrimental effect than allelopathy and both processes together decreasing oak biomass by 50%. Although untargeted metabolomic analysis by UHPLC failed to identify any potentially allelopathic substances involved, our study demonstrates a lower but critical contribution of chemical interference on oak seedling-moor grass competition compared to exploitation processes. To ensure oak regeneration, management of forest ecosystems should thus first focus on reducing moor grass close to oak seedlings to help decrease its allelopathic effect and ease resource competition.

Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland

Drained peatlands dominated by purple moor grass (Molinia caerulea) are widespread in the UK and Western Europe. Although substantial carbon stores may be present in these peatlands, in this degraded state they are not currently acting as carbon sinks. Therefore, M.caerulea dominated peatlands have been identified as potential sites for ecohydrological restoration to tackle the current climate emergency. However, at present little is known about whether ditch blocking can raise water tables and promote the recovery of bog plant species, and the subsequent effects on carbon sequestration in these peatlands.To investigate the potential for restoration, we measured changes in water table depth, vegetation composition, photosynthesis at 1000 μmol Photons m−2 s−1 (PG1000), ecosystem respiration (REco) and partitioned below-ground respiration in two M.caerulea dominated peatlands in which drainage ditches had been blocked located in Exmoor National Park, southwest England. Measurements were made in two headwater catchments at ⅛, ¼ and ½ of the distance between adjacent drainage ditches at four control-restored paired sites, during the growing seasons pre- (2012) and post- (2014, 2016 & 2018) restoration.Restoration had a small but significant (p = 0.009) effect on water table depths however, this did not result in a significant change in vegetation composition (p > 0.350). Ecosystem respiration increased in both the control and restored locations following restoration however, this increase was significantly smaller (p = 0.010) at the restored locations, possibly due to a similarly reduced increase in photosynthesis, although this change was not significant (p = 0.116). Below-ground respiration showed no significant changes following restoration.This research illustrates how degraded these shallow peatlands are, and raises concerns that ditch blocking alone may not bring about the high and stable water tables required to perturb the existing Molinia caerulea-dominated ecosystem and substantially alter the carbon balance. Additional restoration measures may be required.

High methane emissions dominated annual greenhouse gas balances 30 years after bog rewetting

Abstract. Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus potentially implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration are scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated sites of a bog ecosystem 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha−2 yr−1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha−2 yr−1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of CO2, CH4 and N2O, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha−1 yr−1 and were dominated by large emissions of CH4 (22–51 t CO2-eq ha−1 yr−1), with highest rates found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in the water table, we assume that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of purple moor grass and the plant-mediated transport through its tissues. In addition, as a result of the land use history, mixed soil material due to peat extraction and refilling can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not inevitably limited to a short-term period.

Long-term ecological study (palaeoecology) to chronicle habitat degradation and inform conservation ecology: an exemplar from the Brecon Beacons, South Wales

For ecosystems perceived as degraded, but for which the causal factors or timescales for the degradation are disputed or not known, long-term (palaeo-)ecological records may aid understanding and lead to more meaningful conservation approaches. To help ‘bridge the gap’ between (very) long-term ecology and contemporary ecology for practical application, there have been calls for working relationships to be established between palaeoecologists and conservation ecologists. One environment in which this has been attempted is blanket mire. Many blanket mires in Europe are degraded and contain few sphagna. In South Wales, almost all exhibit symptoms of degradation, with dominance by purple moor grass (Molinia caerulea) widespread. We used palaeoecological techniques on three peat profiles in the Brecon Beacons to investigate vegetation history of high-altitude blanket mire to help assess the relative contribution of various factors in mire degradation and to inform strategies for mire conservation and restoration management. We found that declines in sphagna preceded the rise to dominance of monocotyledons. Macrofossil records showed that although Molinia was already present on the Beacons before the start of the industrial revolution, its major rise to dominance in one profile was within the 20th Century, coincident with evidence for local fire. In another profile, it was out-competed by Eriophorum vaginatum after the start of the industrial revolution; there is circumstantial evidence to suggest that a reduction in burning contributed to the rise in E. vaginatum. Conservation management to reduce the current local dominance of both Eriophorum and Molinia is supported by the palaeoecological data, but severe erosion and hagging of peat will constrain practical methods for achieving this on the Beacons until the peat is stabilised. We suggest that palaeoecological techniques have wider applicability in conservation.

Wpływ występowania ziół i chwastów na zróżnicowanie wartości gospodarczej runi łąk

The investigations carried out in 2008–2010 concerned plant communities in the Noteć Leniwa River valley characterised by high and even outstanding natural values and of high valorisation class (IXD, VIII, V, IVB and IIIA). They occur in marshy (High-sedge rushes), strongly wet (Areas with moss and Semi-natural wet) and moderately wet (Purple moor grass and Cnidium meadows or Semi-natural fresh) sites. Mean proportions of herbs and weeds in the sward of these communities are very high and range from 15.9% up to even 86.1%. The economic value of these communities varies depending on their floristic composition. Hay yields differ and range from 3.1 to 6.5 t/ha, while the sward fodder value (SFV) – from 2.6 to 7.2. Badania wykonane w latach 2008–2010 dotyczą zbiorowisk w dolinie rzeki Noteci Leniwej o dużych, a nawet wybitnych walorach przyrodniczych i o wysokiej klasie waloryzacyjnej: IXD, VIII, V, IVB i IIIA. Występują one w siedliskach bagiennych (Szuwary wielkoturzycowe), silnie wilgotnych (Mechowiska i Półnaturalne łąki wilgotne) oraz umiarkowanie wilgotnych (Łąki trzęślicowe i selernicowe i Półnaturalne łąki siedlisk świeżych). Średni udział ziół i chwastów w runi tych zbiorowisk jest bardzo wysoki i wynosi od 15,9% do aż 86,1%. Wartość gospodarcza zbiorowisk w zależności od składu florystycznego jest zróżnicowana. Plon siana wynosi 3,1 do 6,5 t/ha, a wartość użytkowa runi, Lwu = 2,6 do 7,2.

FREQUENCY DISTRIBUTIONS OF 90SR AND 137CS CONCENTRATIONS IN AN ECOSYSTEM OF THE “RED FOREST” AREA IN THE CHERNOBYL EXCLUSION ZONE

In the most highly contaminated region of the Chernobyl Exclusion Zone, the "Red Forest" site, the accumulation of the major dose-affecting radionuclides (90Sr and 137Cs) within the components of an ecological system encompassing 3,000 m(2) was characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants), and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the 90Sr and 137Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values was close to a logarithmically-normal leptokurtic distribution with a significant right-side skew. While it is important to identify localized areas of high contamination or "hot spots," including these values in the arithmetic mean may overestimate the exposure risk. In component sample sets that exhibited logarithmically normal distribution, the geometric mean more accurately characterizes a site. Ideally, risk assessment is most confidently achieved when the arithmetic and geometric means are most similar, meaning the distribution approaches normal. Through bioaccumulation, the highest concentrations of 90Sr and 137Cs were measured in the blue moor grass and spade-footed toad. These components also possessed distribution parameters that shifted toward a normal distribution.

リンドウにさび胞子世代を有するヌマガヤさび病菌 Puccinia moliniae , 特にリンドウが自生しないヌマガヤ湿原における発生特徴について

リンドウにさび胞子世代を有するヌマガヤさび病菌 Puccinia moliniae , 特にリンドウが自生しないヌマガヤ湿原における発生特徴について

Accumulation of 226Ra, 238U and 230Th by wetland plants in a vicinity of U-mill tailings at Žirovski vrh (Slovenia)

The impact of a U-mill tailing on radionuclide accumulation by plants was assayed. In particular, a preliminary screening of 226Ra, 238U and 230Th in Marsh marigold (Caltha palustris L.), soft rush (Juncus effusus L.) and Tall Moor grass (Molinia arundinacea (L.) Moench) grown in a marsh habitat is presented. Activity concentrations for the studied radionuclides and their transfer factors for the particular plants are shown and discussed.

Biomonitoring of traffic-related nitrogen oxides in the Maurienne valley (Savoie, France), using purple moor grass growth parameters and leaf 15N/ 14N ratio

Effects of traffic-related nitrogenous emissions on purple moor grass ( Molinia caerulea (L.) Moench) transplants, used here as a new biomonitoring species, were assessed along 500 m long transects orthogonal to roads located in two open areas in the Maurienne valley (French Alps). Leaves were sampled during summer 2004 and 2005 for total N-content and 15N-abundance determination while nitrogen oxides (NO and NO 2) concentrations were determined using passive diffusion samplers. A significant and negative correlation was observed between plant total N-content, and 15N-abundance and the logarithm of the distance to the road axis. The strongest decreases in plant N parameters were observed between 15 and 100 m from road axis. They were equivalent to background levels at a distance of about 800 m from the roads. In addition, motor vehicle pollution significantly affected vegetation at road edge, as was established from the relationship between leaf 15N-abundance, total N-content and road traffic densities.

Successional changes on a former tank range in eastern Germany: Does increase of the native grass species Molinia caerulea cause decline of less competitive Drosera species?

Summary Invasion of natural ecosystems by weedy grasses is often associated with increasing levels of disturbance. However, there is substantial evidence that cessation of disturbance can also lead to plant invasions. This paper explores vegetation development on a former military training area in eastern Germany. Many military training areas have a high nature conservation value as they offer large un-fragmented areas and valuable open landscapes. In eastern Germany, 4.4% of the land is covered by military training facilities. Following German reunification in 1990 large tracts of land that had been used for military training purposes were converted to civil use. Cessation of military activity is leading to a decline of open habitats through natural succession. The study investigates whether succession is accompanied by a spread of dominant species, e.g. Purple moor grass (Molinia caerulea L. Moench) and whether this process results in a decline of pioneer species (e.g., Drosera species). As a potential management option we explored grazing by moose (Alces alces L.) and other wild animals. The current state of the vegetation and its development was investigated at landscape and species levels. The influence of animals was documented by determining the type of ground disturbance and the impact on the herbaceous vegetation. The trajectory of succession involves the increase of species with high competitive abilities, particularly Molinia caerulea, and a decline of less competitive Drosera species. The pattern of development of the vegetation suggests that the Drosera species will soon survive in only a few locations. Wild animals exerted a significant influence on the vegetation, with most disturbances being the result of trampling. Tracks left by animals can provide regeneration niches for the Drosera species. However to guarantee the maintenance of large open habitats other management practices such as sod cutting are required.

Different responses of Molinia caerulea plants from three origins to CO2 enrichment and nutrient supply

Abstract The global environmental change factors eutrophication and CO 2 enrichment will affect carbon and nutrient cycling in plants and ecosystems. In order to study their interactions on plant performance, growth chamber experiments were performed with plants from three origins of the common but ecologically variable Purple Moor Grass ( Molinia caerulea (L.) Moench) grown in a bi-factorial combination of two levels of nutrients (for N: 31 or 62 kg ha −1 year −1 ) and CO 2 (400 or 600 μmol mol −1 CO 2 ). Plants were established from ramets with known start weights so that total biomass accumulation of each plant over time could be analysed. Plant phenology, leaf properties and the biomass of different fractions (inflorescences, leaves, stems and rootstocks) were investigated to identify treatment effects on plant development and allocation patterns. The few consistent responses identified in the plants were a significant increase in leaf biomass by doubling the nutrient supply and plants exposed to elevated CO 2 showing a reduced specific leaf area (SLA), an increased number of senescent leaves and increased rootstock growth. Increasing the nutrient supply had greater effects on aboveground biomass than raising the CO 2 concentrations but significant interactions between the two plant fertilisers were absent. The variable responses of the ramets to the addition of resources were largely modified by their phenology and their readiness to switch from vegetative to reproductive growth. We conclude that differences in phenology and ecological behaviour of ecotypes of the same plant species will largely affect their response to environmental change.

The role of forest maturation in causing the decline of Black Grouse Tetrao tetrix

Black Grouse Tetrao tetrix in Britain have declined through the 20th century, and most birds are now in Scotland. Many causes for this decline have been suggested, notably agricultural intensification, increased grazing levels and moorland afforestation. We examine habitat correlates of Black Grouse distribution and population change from a 700‐km2 area in the core of the Scottish range, where the numbers of lekking male Black Grouse declined by an estimated 70% to 270 between 1990 and 2002. Habitat data were derived from satellite imagery, in combination with map and field‐collected data. Lek occurrence, lek size and changes in lek size were all correlated with forest structure, either positively with the amount of pre‐thicket forest cover, or negatively with closed canopy cover. Additional effects of the cover of grass moor and dry heath suggest that Black Grouse are most likely to occur where moorland comprises Heather Calluna vulgaris and grass mosaics. Analysis of the change in Black Grouse abundance within 1.5 km of discrete forest blocks suggests that forest maturation, which has been the dominant habitat change during the course of the study, alone accounts for 58–78% of the decline. Given the close association of Black Grouse and the occurrence of woodland (and particularly conifer plantation) throughout much of their British range, these findings can be used to inform the design of management schemes for the recovery of Black Grouse.

Developing a fire danger rating system for the United Kingdom

Prescribed burning (muirburn) is used extensively in upland Britain for habitat management for sheep, red deer (Cervus elaphus) and red grouse (Lagopus lagopus scoticus), an upland game bird that lives on heather (Calluna vulgaris) moorland. Although forest fires are unusual, wildfires are common in heathland (dominated by C. vulgaris, sometimes with Ulex gallii, western gorse), in stands of Ulex europaeus (gorse), especially where these are close to urban sites, and in grasslands dominated by Molinea caerulea (purple moor grass). Fire hazard is increasing in many areas for a variety of reasons including a reduction in man-power available for prescribed burning and reduced grazing offtake. Fire risk is also increasing due to recent changes in legislation permitting access to the countryside and an increase in recreational activities. While successfully predicting periods of exceptional fire weather conditions, the Met Office Fire Severity Index does not provide specific predictions of fire behaviour for different vegetation types, nor is it sufficiently sensitive for identifying conditions suitable for prescribed burning. C. vulgaris is a unique fuel forming a dense canopy of fine shoots with a proportion of dead fuel suspended in the canopy. The live fuel can, under certain circumstances, have a very low fuel moisture content (below 45%). This may occur when shoots are damaged by frost and ice or when the ground is cold or frozen and so reducing water uptake by the shoots. In this paper, we discuss the development of a fire danger rating system for the United Kingdom with regard to the unique situation of fuel characteristics, availability of numerical meteorological data, prescribed burning regime and infrastructure.

Habitat associations of breeding Meadow Pipits Anthus pratensis in the British uplands

Habitat associations of Meadow Pipits breeding in British upland 1 km and 10 km squares were investigated using data from the British Trust for Ornithology's (BTO) Breeding Bird Survey (BBS, 1994–97), The New Atlas of Breeding Birds in Britain and Ireland 1988–1991 and habitat data from the Institute of Terrestrial Ecology's (ITE) Land Cover Survey (1994). Meadow Pipit density was highest in 200 m sections of BBS 1 km transects containing unenclosed grass moor, heather and bog, but there was no difference in Meadow Pipit density between these habitat types. Meadow Pipit density (number of individuals per 1 km square) increased with heather cover up to about 7.5 200 m sections (of ten per 1 km square) of heather, but fell thereafter. There was a positive association between Meadow Pipit density and the extent of grass moor cover. The ITE Land Cover data gave results that were consistent with the BBS habitat data at both the 1 km and 10 km square scale. There was a non-linear relationship between hill grass cover and Meadow Pipit abundance, which reached a maximum when hill grass covered between 40%and 60% of a square. Our results suggest that a mosaic of heather, bog and grassland may be the optimum habitat for Meadow Pipits. Recent changes in land management practices may have led to the disappearance or degradation of these mosaics in some areas. Meadow Pipits are widespread and easily counted. We suggest that this species might be a useful bioindicator of changes in heather and grassland ratios that result from land management practices such as grazing and rotational burning, though further research is required.

Recent rise to dominance of Molinia caerulea in environmentally sensitive areas: new perspectives from palaeoecological data

Summary 1. A characteristic of some heath and moorland areas in maritime north‐west Europe is the widespread dominance of Molinia caerulea (purple moor grass). The overwhelming local supremacy of this species concerns farmers, owing to its relatively low palatability for grazing stock, and conservationists, owing to the monotonous, species‐poor landscapes that often result under Molinietum. 2. In some environmentally sensitive areas (ESAs) in England and Wales, Molinietum is believed to have ousted Callunetum in recent decades; experiments sponsored to control the species have predicated its infiltration and replacement of heather‐dominated stands. 3. Experimental control of Molinia in ESAs on Exmoor, England, was paralleled by palaeoecological studies to verify its recent rise, assess its status in moorland, and test the utility of the techniques for such research. 4. Peat profiles from two localities on Exmoor were sampled and subjected to recently developed techniques of plant macrofossil counting and to conventional pollen analysis. One locality was ‘white moor’, clearly dominated by Molinia; the other was ‘grey moor’ (an admixture of ericaceous shrubs) that had become invaded (allegedly recently) by Molinia. 5. Dating of profiles employed a range of methods, including conventional radiocarbon dating, Accelerator Mass Spectrometry (AMS) dating and the counting of spheroidal carbonaceous particles, to attempt to delimit horizons of recent peat growth. 6. The pollen and macrofossil data confirmed the recent ousting of Calluna and rise to dominance of Molinia in the grey moor, but also provided evidence of an earlier unsuspected (pre‐Callunetum) presence of Molinia. The overwhelming dominance of Molinia in the white moor was also a recent phenomenon, but was only partly at the expense of Calluna. The palaeoecological data indicated a greater antiquity and former abundance of Molinia than is often appreciated and suggested that, over the past millennium, vegetation dominance has alternated between Callunetum and grass moor containing at least some Molinia, while the former Calluna‐dominated grey moor itself developed originally from grass moor. 7. These findings have implications for conservation management and for restoration targets in ‘degraded’ moorland. Similar palaeoecological studies have since been adopted in Wales, directly to inform conservation and management policy.

Grass moor communities 20 and 39 years after severe accidental fires

Summary The species composition of plant communities on three adjacent moorland areas were determined during summer 1996. Severe accidental fires in 1957 and 1976 removed the vegetation, the litter layers and virtually all the soil organic matter in the organic horizons of what were acidic stagnohumic gley soils before the fires, leaving relatively dry but acidic soils in the two burned areas. Together with the surrounding unburned area, which was classified as Molinia caerulea-Potentilla erecta mire (M25) in the National Vegetation Classification (NVC) of Great Britain, the areas provided an opportunity to investigate stages of post-fire community development. The areas were sampled with 18 quadrats and the plant communities were divided into six groups by TWINSPAN. Four of the groups were typical of dry acidic soils and these groups included vegetation on both burned areas, which were categorised as NVC Deschampsia flexuosa grassland (U2). This study provides information both about the plant succession ...