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Native upland species, Nardus stricta, Eriophorum vaginatum, Erica cinerea and Vaccinium vitis-idaea were given 3 or 60 kg N ha−1 yr−1, over 2 yr, applied as a mist (NH4NO3). The high N treatment increased above-ground biomass in all four species, but only significantly in E. cinerea, E. vaginatum and N. stricta. Biomass increases in E. vaginatum and N. stricta resulted from enhanced tiller production rather than shoot elongation. Root growth increased in N. stricta, so that root[ratio ]shoot ratio in this species was unchanged by N. Root growth in E. vaginatum, E. cinerea and V. vitis-idaea did not respond to N and their root[ratio ]shoot ratios decreased. Tissue N concentrations increased in both shoots and roots of all species in response to N. The accumulated foliar N did not increase the proportion of N allocated to Rubisco and the photosynthetic capacities of N. stricta, E. vaginatum and V. vitis-idaea were unchanged. Thus growth responses to N were due to altered allocation rather than increased rate of photosynthesis per unit leaf area. The high N treatment increased flower production significantly in E. cinerea but not in the other species. Although in this experiment dwarf shrubs were more responsive than graminoids to N, in the field at current N inputs the enhanced tillering of the graminoids may be more competitively advantageous, especially where gaps develop in the canopy. Thus increasing N deposition may lead to increased grassiness of upland heath, and in particular, a spread of N. stricta.

[Abstract] Background and aims: Heathlands are a broad vegetation type characterized by the dominance of evergreen shrub species that thrive on nutrient-poor soils, thus sensitive to small changes in soil conditions. Here we aimed to identify soil gradients related to climate, management and main species in wet heathlands. Methods: Soil nutrient levels, organic matter and acidity were studied at two soil depths on ninety plots from 18 sites in Erica mackayana wet heaths of NW Iberian Peninsula, in relation to presence and cover of structural plant species (shrubs and graminoids) at two scales: plot and site (landscape) scale. Results: We identified one main soil gradient explained by soil organic matter (SOM), the effective cation exchange complex (eCEC), available phosphorus (P), and Aluminium-Calcium ratio (Al:Ca). Cattle density had a positive correlation with the main gradient in the surface layer, all other climate and management factors were unrelated to soil conditions. Molinia caerulea had a positive relation with SOM, eCEC, basic cations and low Al:Ca ratio. Erica cinerea showed the opposite reaction at both scales. Ulex gallii showed a negative correlation with C:N ratio at the plot scale and deeper layer. Conclusion: SOM accumulation, low nutrient levels and Al toxicity explain the uniqueness of E. mackayana heathland vegetation and soils. Main indicator species react to soil conditions at plot and landscape scales. Cattle density correlated positively with soil nutrient levels, but density of wild ponies is unrelated to soil conditions. Large herbivores, especially ponies, are needed for conservation management of these heathlands.

Honey authentication is a complex process which traditionally requires costly and time-consuming analytical techniques not readily available to the producers. This study aimed to develop non-invasive sensor methods coupled with a multivariate data analysis to detect the type and percentage of exogenous sugar adulteration in UK honeys. Through-container spatial offset Raman spectroscopy (SORS) was employed on 17 different types of natural honeys produced in the UK over a season. These samples were then spiked with rice and sugar beet syrups at the levels of 10%, 20%, 30%, and 50% w/w. The data acquired were used to construct prediction models for 14 types of honey with similar Raman fingerprints using different algorithms, namely PLS-DA, XGBoost, and Random Forest, with the aim to detect the level of adulteration per type of sugar syrup. The best-performing algorithm for classification was Random Forest, with only 1% of the pure honeys misclassified as adulterated and <3.5% of adulterated honey samples misclassified as pure. Random Forest was further employed to create a classification model which successfully classified samples according to the type of adulterant (rice or sugar beet) and the adulteration level. In addition, SORS spectra were collected from 27 samples of heather honey (24 Calluna vulgaris and 3 Erica cinerea) produced in the UK and corresponding subsamples spiked with high fructose sugar cane syrup, and an exploratory data analysis with PCA and a classification with Random Forest were performed, both showing clear separation between the pure and adulterated samples at medium (40%) and high (60%) adulteration levels and a 90% success at low adulteration levels (20%). The results of this study demonstrate the potential of SORS in combination with machine learning to be applied for the authentication of honey samples and the detection of exogenous sugars in the form of sugar syrups. A major advantage of the SORS technique is that it is a rapid, non-invasive method deployable in the field with potential application at all stages of the supply chain.

Lactic acid bacteria and bifidobacteria (LAB and Bifido), isolated from the gastrointestinal tract of Apis mellifera intermissa (BGIT), honey (H), propolis (P) and bee bread (BB) of hives set in different vegetations (wildflowers, caraway, orange blossom, Marrubium vulgare, Eucalyptus and Erica cinerea), were subjected to analysis of their antibacterial potential. Isolates able to inhibit Staphylococcus aureus were selected and identified with MALDI-TOF MS leading to 154 strains representing 12 LAB and Bifido species. Lactiplantibacillus plantarum, Pediococcus pentosaceus and Enterococcus faecalis were predominantly found in all matrices. BGIT showed the highest LAB and Bifido diversity with exclusive occurrences of five species (including Bifidobacterium asteroides and Limosilactobacillus fermentum). Honey was the second origin harboring an important variety of LAB species of which Apilactobacillus kunkeei and Enterococcus mundtii were characteristic of both H and BGIT. Principal components analysis revealed associations between antibacterial activities of LAB and Bifido, matrices and honey bee forage plants. Inhibition trends of S. aureus and Citrobacter freundii were highlighted with: L. plantarum from BGIT, P, H of bees feeding on E. cinerea; Pediococcus pentosaceus from BGIT, P, BB associated with E. cinerea; and Bifidobacterium asteroides from BGIT/orange blossom system. However, Enterococcus faecium associated with BGIT/Eucalyptus system antagonized Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Our findings highlighted noteworthy effects of bee forage plants on the antibacterial activity of LAB and Bifido. Our approach could be useful to identify multiple conditions promoting antibacterial potency of LAB and Bifido under the combined effects of feeding plants and living matrices.

Nitrate is a limiting resource in heathland acid soils. Nitrate levels increase in heathland soils after Pteridium aquilinum invasions, and this species is assumed to biologically control nitrogen cycle processes, thus increasing nitrate availability. We compared how P. aquilinum (bracken) and Erica cinerea (bell heather) modify processes driving nitrate availability along a soil pH gradient in a Natura 2000 reserve facing bracken invasion. Soil nitrate and ammonium concentrations, substrate‐induced respiration (SIR), denitrification and nitrification enzyme activities (DEA and NEA, respectively), root procyanidin concentrations, and denitrification inhibition by procyanidins were measured on five sites under P. aquilinum and E. cinerea stands. NEA and nitrate levels were higher, and ammonium levels and SIR lower, for P. aquilinum in the most acid soils. Procyanidins from both species induced the same level of denitrification inhibition, soil nitrate being correlated with root procyanidin concentration for both species. Soil nitrate correlated with NEA only for P. aquilinum. Our results show that both species increased procyanidin production in the most acid soils, thereby reducing denitrification and decreasing nitrate loss, this process being more efficient for E. cinerea. However, P. aquilinum additionally increased nitrification, and this double control on nitrification and denitrification was very efficient to increase soil nitrate availability in the most acid soils. This may participate to the success of P. aquilinum invasions in heathlands. This shows that approaches for bracken control in heathlands should better account for belowground processes and, more generally, that biological denitrification inhibition by plants may be a widespread phenomenon influencing soil N dynamics in N‐poor environments.

1. In plants, long-distance dispersal (LDD) is a widespread phenomenon of great importance, especially in spatial dynamics such as in metapopulations, invasions and migration. Much has become known about the mechanisms underlying LDD by wind, but selective release mechanisms have received little attention. Recent papers call for particular effort in clarification of the seed release stage of the dispersal process, which is our aim here. 2. We studied non-random seed release at a range of spatial scales, from the individual plant to species' spatial dynamics. We did this by combining wind tunnel experiments, field trap data and simulation and analytical models, using two common wind-dispersed heathland plants (Calluna vulgaris and Erica cinerea) as study species. 3. In both species, seed release from the plant increases with increasing wind velocity. There is a minimum release threshold, above which the probability of seed release increases with increasing wind velocity. The drag caused by the wind is the motive force for seed release. 4. Simulations of seed dispersal with non-random seed release match measured dispersal kernels better, especially in the tails, than 'conventional' simulations with random seed release. Seed release during gusts gives the most realistic kernel. This result matches previous findings that seeds are released primarily at the start of gusts and during turbulent wind flow. 5. Dispersal kernels assuming non-random seed release had large impacts on analytically modelled population migration rates. Wavespeeds assuming seed release during gusts were, on average, more than double those assuming random seed release. Increases in wavespeeds under different seed release assumptions were due mostly to increases in the tail of the dispersal kernel. 6. Synthesis. This study shows how the small-scale process of a seed being released from the plant could affect the large-scale spatial dynamics of plant species in landscapes. The mechanism of non-random seed release, i.e., seed release during gusts, is an important mechanism for attaining LDD by wind. As such, non-random seed release influences landscape-scale species dynamics such as invasions and migration.

The size and shape of the tail of the seed dispersal curve is important in determining the spatial dynamics of plants, but is difficult to quantify. We devised an experimental protocol to measure long-distance dispersal which involved measuring dispersal by wind from isolated individuals at a range of distances from the source, but maintaining a large and constant sampling intensity at each distance. Seeds were trapped up to 80 m from the plants, the furthest a dispersal curve for an individual plant has been measured for a non-tree species. Standard empirical negative exponential and inverse power models were fitted using likelihood methods. The latter always had a better fit than the former, but in most cases neither described the data well, and strongly underestimated the tail of the dispersal curve. An alternative model formulation with two kernel components had a much better fit in most cases and described the tail data more accurately. Mechanistic models provide an alternative to direct measurement of dispersal. However, while a previous mechanistic model accurately predicted the modal dispersal distance, it always under-predicted the measured tail. Long-distance dispersal may be caused by rare extremes in horizontal wind speed or turbulence. Therefore, under-estimation of the tail by standard empirical models and mechanistic models may indicate a lack of flexibility to take account of such extremes. Future studies should examine carefully whether the widely used exponential and power models are, in fact, valid, and investigate alternative models.

The aim of the current study was to determine the profile and content of polyphenols present in Erica cinerea, an important plant species from Northern Portuguese flora and often reported as having anti-inflammatory, antioxidant, and anti-radical activity. The analysis of polyphenols was performed by HPLC-DAD/UV-Vis, and the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) method was used to evaluate its radical scavenging activity. HPLC analysis showed that both plants presented a great diversity of compounds, with 33% flavones, 28% flavanols, and 26% hydroxycinnamic acids. The antiradical activity was dose-dependent, and the IC50 values were 0.251 mg mL−1. Based on our study, E. cinerea presented interesting bioactive compounds and it can be used to extract and purify bioactive polyphenols to be used in pharmaceutical or agro-food industries.

The effects of heather (composed primarily of Calluna vulgaris with a smaller content of Erica umbellata and Erica cinerea) consumption on the establishment of incoming infective larvae (experiment 1, preventive treatment) and an adult worm population (experiment 2, curative treatment) were investigated in Cashmere goats experimentally infected with Trichostrongylus colubriformis. In experiment 1, 12 castrated male goats were divided into two groups: heather-supplemented vs. non-supplemented animals. After 2 weeks of adaptation to the diet, all goats were experimentally infected per os with 6,000 T. colubriformis third-stage larvae. Three weeks post-infection, the goats were slaughtered, and worm counts as well as female worm fecundity and development were determined. Heather consumption was associated with a close to significant (P = 0.092) reduction (mean 14 %) in larvae establishment. No effect on fecundity was observed, but the length of female worms in supplemented goats was greater (P < 0.001). In experiment 2, 15 non-lactating does were experimentally infected with 6,000 T. colubriformis third-stage larvae. At 6 weeks post-infection, three groups were established: control, heather-supplemented and heather-supplemented with polyethylene glycol. Individual faecal nematode egg output was measured twice weekly to assess gastrointestinal nematode egg excretion. The goats were slaughtered 5 weeks after heather administration (11 weeks post-infection), and worm counts as well as female worm fecundity and development were subsequently determined. Heather administration was associated with a significant (P < 0.001) decrease (between 47 and 66 % compared with control group) in egg excretion from 45 to 76 days post-infection. Although worm counts and female fecundity were lower in supplemented goats, no significant differences were observed. Overall, the results showed a reduction in T. colubriformis larvae establishment and a decrease in nematode egg excretion when heather was administered in experimentally infected goats. The heather plus polyethylene glycol treatment reduced nematode egg excretion levels at the same proportion as heather, thereby suggesting that the threshold of tannins required for an anthelmintic effect is most likely quite low.

Purpose Aluminium partitioning in the solid fraction and aluminium in solution in the bulk and rhizospheric soil of different plant species colonising an abandoned Cu mine slope ( Calluna vulgaris , Erica cinerea and Salix atrocinerea ) and mine dump ( C. vulgaris and E. cinerea ) were investigated. The aim of the study was to determine the changes that the species induce in the Al forms in the rhizosphere in order to adapt to heterogeneous substrates. Materials and methods Al was extracted from the solid phase with different solutions: ammonium oxalate (Alo), sodium pyrophosphate (Alp), copper chloride (Alcu), lanthanum chloride (Alla) and ammonium chloride (AlNH 4 ). The following Al fractions were obtained: inorganic non-crystalline Al (Alop = Alo–Alp), highly stable organoaluminium complexes (Alpcu = Alp-Alcu), organoaluminium complexes of intermediate stability (Alcula = Alcu–Alla) and labile organoaluminium complexes (Alla). The concentration of Al present in the aqueous phase was also determined. Results and discussion The pH of the soil in the mine slope was close to 7, and the roots of Ericaceae caused strong acidification so that the pH of the rhizospheric soil was low (3.6–4.7). In contrast, the pH of the bulk and the rhizospheric soil of S. atrocinerea remained close to 7. In the mine dump (pH 3.7), the changes in the pH of the Ericaceae rhizosphere in relation to the bulk soil were not as marked as in the mine slope. Alop predominated in the solid phase (more than 70% of the Alo), and Alpcu predominated in the organoaluminium complexes (more than 55%), followed by Alcula (13% and 47%) and Alla (3% and 21%). The concentration of Al in solution was significantly related to the concentrations of AlNH 4 ( r  = 0.43), Alla ( r  = 0.50) and Alcula ( r  = 0.45). Conclusions Ericaceae species grew in dump and slope materials because they modified the pH of the rhizospheric soil, while S. atrocinerea only grew in areas where the soil conditions were close to neutral. The concentration of aluminium fractions was higher in the Ericaceae rhizosphere soil than in Ericaceae bulk soil, S. atrocinerea rhizosphere and bulk soils. Moreover, highly stable organoaluminium complexes predominated, and the dissolved Al concentration was low, despite the strong acidity.