Introduction. This study investigated the ecology of Pallavicinia lyellii in a mire habitat dominated by Molinia caerulea, including potential abundance, frequency of sexes and sporophytes, and ...characteristics of the light climate beneath the herbaceous canopy.
Methods. Within the study site (Cors Fochno, Wales, UK), P. lyellii was surveyed in March 2020. Abundance was measured as counts of colonies, their sexual composition was recorded, and number of sporophytes determined. Photosynthetic photon flux density (PPFD) was measured beside colonies, paired with measurements taken 1 m above the colony under open sky. A hemispherical sky image was captured, and sun tracks overlaid, at a representative colony.
Results. Fifty-eight colonies of P. lyellii occurred, in two populations. One population exhibited male bias, a low portion of sterile colonies and a relatively large number of sporophytes. The other exhibited female bias, a high portion of sterile colonies and very few sporophytes. Molinia caerulea blocked ca. 91% of PPFD, and light at colonies of P. lyellii was consistently low (mean PPFD = 29 μmol m
−2
s
−1
). Hemispherical photography shows no direct sunlight may reach P. lyellii during October-February and suggests during the remainder of the year such events could be extremely limited.
Conclusions. Molinia mire can support large populations of P. lyellii and will be important for its future survival in Britain. Research is needed to quantify the microhabitat favoured by the liverwort, such as relationship to light, hydrology and water chemistry, and how these can be affected by management.
Multiple land‐use change drivers affect, in most cases negatively, the biodiversity in species‐rich meadows. Empirical data that can help to disentangle the effects of individual drivers and quantify ...the time required for a biodiversity response are seldom available. Management decisions are often based on short‐term experiments or observational data. A 15‐year field experiment, comprising a factorial combination of fertilization, mowing and removal of the dominant species Molinia caerulea, was established in an oligotrophic wet meadow in Czech Republic. Each of the eight factorial combinations was replicated three times. Percentage cover for all species was monitored annually in 1‐m² plots and species' presence recorded in each cell of a continuous square grid of 25 cells (0·1 × 0·1 m each). These data enabled various scale‐dependent estimates of species richness. The species composition of individual treatment combinations diverged over time, particularly at the start of the experiment, and by the latter stages resembled various typical grassland communities from the surrounding landscape. Fertilization had the most pronounced effect, leading to a sharp decrease in species richness, most rapidly at the smallest spatial scale. Mowing had on average a positive effect on species richness and led in most cases to spatially homogeneous species composition. The removal of Molinia had a positive effect on species richness, especially in unmown unfertilized plots. The effects of each factor were dependent on the combination of the other two factors, and also on time, with some effects continuously increasing throughout and some diminishing by the end of the experiment. The process of competitive exclusion with fertilization and cessation of mowing was, in some treatment combinations, rather slow. Synthesis and applications. Land‐use change drivers act in combination, and their effects on the structure of species‐rich wet meadows are dependent on both the temporal and spatial scales considered. Short‐term experiments might underestimate the response of vegetation and thus provide erroneous conservation recommendations. Mowing was only effective in preventing species richness decline caused by fertilization in the short term. The presence of a single dominant species can modify the effectiveness of conservation measures.
Ecosystem carbon (C) accrual and storage can be enhanced by removing large herbivores as well as by the fertilizing effect of atmospheric nitrogen (N) deposition. These drivers are unlikely to ...operate independently, yet their combined effect on aboveground and belowground C storage remains largely unexplored. We sampled inside and outside 19 upland grazing exclosures, established for up to 80 years, across an N deposition gradient (5–24 kg N ha⁻¹ yr⁻¹) and found that herbivore removal increased aboveground plant C stocks, particularly in moss, shrubs and litter. Soil C storage increased with atmospheric N deposition, and this was moderated by the presence or absence of herbivores. In exclosures receiving above 11 kg N ha⁻¹ year⁻¹, herbivore removal resulted in increased soil C stocks. This effect was typically greater for exclosures dominated by dwarf shrubs (Calluna vulgaris) than by grasses (Molinia caerulea). The same pattern was observed for ecosystem C storage. We used our data to predict C storage for a scenario of removing all large herbivores from UK heathlands. Predictions were made considering herbivore removal only (ignoring N deposition) and the combined effects of herbivore removal and current N deposition rates. Predictions including N deposition resulted in a smaller increase in UK heathland C storage than predictions using herbivore removal only. This finding was driven by the fact that the majority of UK heathlands receive low N deposition rates at which herbivore removal has little effect on C storage. Our findings demonstrate the crucial link between herbivory by large mammals and atmospheric N deposition, and this interaction needs to be considered in models of biogeochemical cycling.
Species-rich oligotrophic meadows are affected by a wide range of management interventions that influence their functioning and capacity to deliver ecosystem services, but long-term studies on the ...above-and belowground adaptations to different management tools are still scarce. We focused on the interactive effects of NPK fertilization, mowing, and removal of the initially dominant species (Molinia caerulea) on plant, soil, and microbial responses in wet oligotrophic grassland in a 16-year full-factorial manipulative experiment. Changes in vegetation composition, soil pH, and nutrient availability were accompanied by altered microbial phospholipid fatty acid (PLFA) composition, whereas treatment effects on soil microbial biomass and carbon (C) mineralization were mainly related to changes in soil organic matter (SOM) content and nutrient availability. Fertilization decreased plant species richness aboveground and lowered SOM storage and microbial activity belowground. Mowing preserved high plant diversity and led to more efficient recycling of N within the grassland, whereas Molinia removal significantly affected only plant community composition. Mowing combined with fertilization maintained high species richness only in the short term. Belowground, mowing reduced N leaching from the fertilized system but did not prevent SOM depletion, soil acidification, and concomitant adverse effects on soil microbes. We conclude that annual mowing is the appropriate type of extensive management for oligotrophic species-rich meadows, but the concomitant nutrient depletion should not be compensated for by regular NPK fertilization due to its adverse effects on soil quality.
To compensate for an airport expansion, including construction on valuable wet meadows of a Natura 2000 system, 1.3 ha of turf, cut into blocks, were transferred to artificial basins in a habitat ...garden. To evaluate the impact of translocation on this ecosystem, and thus the success of its preservation, we monitored fungal root colonisation of Molinia caerulea, the diagnostic plant species for wet meadows, along with arbuscular mycorrhizal fungi (AMF) species richness and composition in soils and soil microbial processes for three seasons: prior to the transfer (2013) and the two following years (2014–15). We observed few changes in the fungal colonisation of M. caerulea, suggesting that the fungal associations of this species were unaffected. The number of AMF species declined directly after the translocation; however, in 2015, an increased number of species was recorded. There were no differences in AMF species composition, nor did soil basal respiration rate, substrate-induced respiration (SIR), or substrate-active biomass (Cmic) change over the years. Only metabolic coefficient (qCO2) decreased after the transfer. The small number of effects in fungal root colonisation, AMF diversity, and microbial processes following the translocation of the ecosystem prove its success. This can be attributed to the deep turf translocation that kept the relevant microbial communities almost unaffected.
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•The impact of translocation of wet meadows on soil microorganisms was assessed.•Few changes occurred in the fungal root colonisation of meadow plant species.•AMF species composition was unaffected; AMF species richness fluctuated.•Only metabolic coefficient (qCO2) decreased following the transfer.•Few changes in microbial community parameters prove the transfer's success.
Uncontrolled, large fires are a major threat to the biodiversity of protected heath landscapes. The severity of the fire is an important factor influencing vegetation recovery. We used airborne ...imaging spectroscopy data from the Airborne Prism Experiment (APEX) sensor to: (1) investigate which spectral regions and spectral indices perform best in discriminating burned from unburned areas; and (2) assess the burn severity of a recent fire in the Kalmthoutse Heide, a heathland area in Belgium. A separability index was used to estimate the effectiveness of individual bands and spectral indices to discriminate between burned and unburned land. For the burn severity analysis, a modified version of the Geometrically structured Composite Burn Index (GeoCBI) was developed for the field data collection. The field data were collected in four different vegetation types: Calluna vulgaris-dominated heath (dry heath), Erica tetralix-dominated heath (wet heath), Molinia caerulea (grass-encroached heath), and coniferous woodland. Discrimination between burned and unburned areas differed among vegetation types. For the pooled dataset, bands in the near infrared (NIR) spectral region demonstrated the highest discriminatory power, followed by short wave infrared (SWIR) bands. Visible wavelengths performed considerably poorer. The Normalized Burn Ratio (NBR) outperformed the other spectral indices and the individual spectral bands in discriminating between burned and unburned areas. For the burn severity assessment, all spectral bands and indices showed low correlations with the field data GeoCBI, when data of all pre-fire vegetation types were pooled (R2 maximum 0.41). Analysis per vegetation type, however, revealed considerably higher correlations (R2 up to 0.78). The Mid Infrared Burn Index (MIRBI) had the highest correlations for Molinia and Erica (R2 = 0.78 and 0.42, respectively). In Calluna stands, the Char Soil Index (CSI) achieved the highest correlations, with R2 = 0.65. In Pinus stands, the Normalized Difference Vegetation Index (NDVI) and the red wavelength both had correlations of R2 = 0.64. The results of this study highlight the superior performance of the NBR to discriminate between burned and unburned areas, and the disparate performance of spectral indices to assess burn severity among vegetation types. Consequently, in heathlands, one must consider a stratification per vegetation type to produce more reliable burn severity maps.
The paper presents concentrations and correlations between Zn, Cd and Pb in the aboveground parts of purple moor-grass (
L.) in forest soils heavily contaminated with heavy metals around a zinc and ...lead ore tailing landfill at Mining & Metallurgy Enterprise “Bolesław” SA in Bukowno. Field observations have indicated that purple moor-grass, which occurs as one of the few vascular plants in locations with tailing mud, is probably a species with high adaptability to conditions in contaminated environments. The research was carried out in a network of 20 regular monitoring sites. At these sites, a detailed inventory of purple moor-grass was carried out and samples of the aboveground parts of the plants were collected from the leaves and ears and from the soil at a depth of 0-20 cm. It was found that there was no significant correlation between the concentration of heavy metals in the soils and aboveground parts of the plants in the most heavily contaminated zones. This may indicate the existence of mechanisms limiting uptake of heavy metals by this species, and therefore the need for further research in the context of its suitability for biological regeneration of tailing landfills and phytosanitary protection of adjoining areas.
Aims
Belowground carbon transfer from plant to plant has been extensively described, but such transfer for nitrogen has been less thoroughly investigated when the donor is a non-N
2
-fixing species. ...This study, applied to forest regeneration, aimed to determine whether tree seedlings facilitated neighbouring grass growth through nitrogen transfer at an early stage of development, thus facilitating nitrogen acquisition by understory species.
Methods
Quercus petraea
seedlings were planted in pots either sole-grown or mixed-grown with
Molinia caerulea
tufts or another oak seedling.
15
N-urea pulse-chase labelling (cotton wick method) was performed in oak shoots and the fate of
15
N in each soil and plant compartment was tracked for one year. N transfer pathways were investigated using two degrees of physical separation between root systems.
Results
Molinia
dry weight was higher when mixed-grown with oak seedlings than when sole-grown. Increase in grass dry weight correlated with N transfer from donor oak to receiver
Molinia
. Interestingly, the presence of
Molinia
increased N rhizodeposition of oak. N allocation in donor oak towards root in winter and shoot in spring was enhanced.
Conclusions
Oak seedlings facilitated
Molinia
growth through rapid N transfer, underlining the ability of non-N
2
-fixing species to supply N to neighbours.
15
N allocation within donor oak and its rhizodeposition depended on neighbour identity.
Key message
Fifteen species are most susceptible to require vegetation control during tree regeneration in the range of our study. Among these 15 species,
Rubus fruticosus
,
Pteridium aquilinum
, and
...Molinia caerulea
cover each more than 300,000 ha of open-canopy forests.
Context
Vegetation control, i.e., the reduction of competitive species cover, is often required to promote tree seedling establishment during the forest regeneration stage. The necessity to control understory vegetation largely depends on the species to be controlled. In order to plan forest renewal operations, it is critical to identify which species require vegetation control during the regeneration stage and to quantify the forest area affected by these species.
Aims
We aimed at identifying the main species requiring vegetation control and at estimating the forest area they cover at the national level.
Methods
Using National Forest Inventory data, we created four indicators based on two levels of plant cover, cross-referenced with two levels of canopy opening, and compared them to the outcome of a survey of forest manager practices.
Results
The best indicator was the one that represented the proportion of forests with open canopy where the species was present with a large cover in the understory. In non-Mediterranean France, according to the indicator, a total of 15 species were found to frequently require vegetation control during the tree regeneration stage.
Pteridium aquilinum
,
Molinia caerulea
, and
Rubus fruticosus
were the main species, and each covered more than 300,000 ha of forest with open canopies, representing about 13% of the total forest area with open canopies outside of the Mediterranean area.
Conclusions
Forests covered by species requiring vegetation control according to forest managers represent a large share of the forest area undergoing regeneration. This study provides the first list of species that require vegetation control based on a methodological protocol that makes it possible to calculate the area associated with each species.
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.
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