Pteridium Aquilinum Research Articles

Geographical distribution of caudatoside and ptaquiloside in bracken ferns in Northern Europe

Bracken ferns (genus Pteridium) are among the most prevalent plants worldwide, with their distribution expanding due to their invasive nature. The environmental implications of their proliferation in areas affected by human activity, natural disasters, or land-use changes are concerning, primarily because of the carcinogenic illudane glycosides they produce. These compounds cause domestic and wildlife animal poisoning, as well as contamination of dairy products and drinking water. Several illudane glycosides are known, but usually only ptaquiloside (PTA) is monitored. This study investigates the spatial and temporal variations in illudane glycosides PTA, caudatoside (CAU) and ptesculentoside (PTE) across two phenotypes of Pteridium aquilinum (vars. aquilinum and latiusculum) over a broad geographic range spanning Denmark, Sweden, and Finland, encompassing 66 locations. We analysed different parts of the fern fronds (the tips and the lowest pinnae) using LC–MS and statistically explored the influence of phenotype, frond part, geographic location, sunlight exposure, and the surrounding ecosystem on glycoside content. Our findings reveal that PTA accounts for approximately two-thirds of the total illudane glycoside content, followed by CAU at nearly one-third, and a minor contribution from PTE. Glycoside levels were not influenced by phenotypic varieties or the studied environmental factors, but were significantly affected by geographic location. Specifically, CAU levels increased progressively towards the northeast, while PTA concentrations were highest in Denmark and markedly decreased in northeastern countries by over threefold, presumably due to climatic gradient. It has been further supported by temporal analysis in selected PTA-dominant regions indicating a reduction in PTA towards the end of the growing season, aligning its levels with those of CAU. Our study highlights that CAU concentrations in bracken ferns may equal or surpass PTA, contesting the prevailing view that PTA is the only notable illudane glycoside in Bracken. To provide unbiased assessment of the potential risks posed by P. aquilinum in the region, environmental and toxicological research should include measurements of not only PTA, but also CAU and, if possible, PTE.

A Novel Method for the simultaneous determination of flavonoids in Pteridium aquilinum via SPE combined with UPLC-DAD via QAMS

A novel analytical method based on ultra-performance liquid chromatography-diode array detector (UPLC-DAD), solid-phase extraction (SPE), and quantitative analysis of multiple components by single marker (QAMS) was developed for the first simultaneous determination of 8 flavonoids in Pteridium aquilinum. The combination of QAMS and SPE demonstrated the convenient and economic advantages of the QAMS method while also exhibiting straightforward and cost-efficient advantages in terms of both the time and solvent usage of the SPE. The contents of the 8 flavonoids in P. aquilinum ranged from 0.59-697.08μg/g. There were no substantial differences in the quantification when comparing the QAMS method and the external standard method (ESM). The standard deviations (SDs, %) obtained by QAMS and ESM were all less than 5%. SPE increased the concentration of flavonoids by 4.18 to 18.9 times. The limits of detection (LODs) and quantification (LOQs) were in the ranges of 0.01-0.15 and 0.06-0.33ng/g, respectively. Method validation revealed the linearity of the calibration curves (R2 ≥ 0.9989), with recoveries between 97.02% and 105%, and the relative standard deviations (RSD) were all lower than 5%. In addition, rhoifolin (4), apigenin (6), and amentoflavone (8) were first reported in P. aquilinum. The results suggested that this method was simple, reliable, and feasible for determining the flavonoids in P. aquilinum samples and could be further applied to various foods and herbal medicine samples.

Ethnobotany around the Virovitica Area in NW Slavonia (Continental Croatia)-Record of Rare Edible Use of Fungus Sarccoscypha coccinea.

Slavonia is the most developed agricultural region in Croatia. With rich and fertile soils that have enabled the cultivation of a wide variety of fruits, vegetables, and cereals, Slavonia has always met the food needs of its population. Today, the biocultural diversity of local varieties and semi-natural vegetation has irretrievably disappeared. Our aim was to document the remaining local knowledge of plant use in this area through in-depth semi-structured interviews, which were conducted in 2022-2023. All possible aspects of the use of plants and fungi were recorded as food, animal feed, medicine, construction, jewelry, rituals and ceremonies, dyes, etc. The names and uses of local plant varieties were also recorded. The results show 1702 entries-a total of 296 plant taxa from 76 families and 28 fungi from 16 families. The most frequently named plants were: Urtica dioica, Robinia pseudoacacia, Rosa canina, and Sambucus nigra. The plants with the greatest variety of uses were Morus alba, Rosmarinus officinalis, Triticum aestivum, and Zea mays. Interesting uses were identified. The leaves of the ornamental plant Hosta sieboldiana are still used today as food for wrapping meat with rice, the aquatic plant Trapa natans is eaten like chestnuts, and Pteridium aquilinum was once consumed as a vegetable. In addition, Ambrosia artemisiifolia and Sambucus ebulus were given to horses to prevent and avoid blood poisoning. Some forest species had a special significance and were revered or favored. The most frequently mentioned edible fungi were Boletus sp., Cantharellus cibarius, and Lactarius piperatus. Auricularia auricula-judae is the only species stated to have been used exclusively as a raw snack. Evidence of edible use of Sarccoscypha coccinea, which was reported as traditionally consumed in the past, was of particular interest. Despite the modernization and agricultural nature of the region, many interesting uses of plants and fungi were identified. Further efforts should be directed towards documenting this knowledge to facilitate its dissemination in the communities that possess it, or at least to preserve it for future generations.

Environmental correlates of Whinchat Saxicola rubetra breeding territory retention in a declining upland population

ABSTRACT Capsule In a 461 km2 unenclosed upland landscape in south-west England, long-term breeding Whinchat Saxicola rubetra persistence is more likely in areas characterized by a mixture of Bracken Pteridium aquilinum, ericaceous vegetation, and very low tree densities, situated in steep-sided valleys at mid-altitudes, further from agriculturally improved grassland or arable. Aims To establish the correlates of Whinchat breeding territory retention between 1979 and 2015–2022 in a declining upland population. Methods Historical Whinchat territories (identified in 1979) were revisited to assess range occupancy, producing a lost (n = 104) and retained (n = 60) sample. Territory retention probability was modelled at local (100 × 100 m) and broad (500 × 500 m) scales against remotely sensed data and field habitat data measured in 2022. Results At the local scale, territory retention probability was greater in steeper valleys, further from arable or agriculturally improved grassland, peaked at five trees per ha in a quadratic response, and where Bracken cover was greater. Bracken cover effects were enhanced when ericaceous vegetation was also present. At the broad scale, retention probability was again greater in steeper valleys, with greater Bracken cover, and at very low tree densities in a quadratic response (but the latter was not important at the bottom of steep-sided valleys). Retention also peaked at around 350–400 m elevation in a quadratic response at the broad scale. Conclusions In this population in south-west England, steep-sided valleys at 350–400 m, with a light scattering of trees, situated further from intensive enclosed farmland are more likely to retain Whinchats long term. Within these areas, a mixed Bracken and ericaceous field-layer should be encouraged, and blanket afforestation avoided, although lower densities of native trees appear to be more tolerated.

Distribution and Conservation Status of Plants’ species in the Botanical Garden and Arboretum domiciled in University of Uyo, Nigeria

This research assessed the plant species composition, distribution and International Union for the Conservation of Nature (IUCN) conservation status of plants in University of Uyo botanical garden and arboretum using systematic sampling technique. The species were sampled in 10 x 10 m quadrats spaced at least regular intervals of 20 m from each quadrat. Thirty-one and thirty-eight species were encountered in the arboretum and botanic garden respectively. In terms of the frequency, Chromolaena odorata and Nauclea diderichii had the highest values (75%), while Acanthus montanus, Anthocleista djalonensis, Anthonotha macrophylla, Baphia nitida, Barteria nigritiana, Carpolobia lutea, Ceiba pentandra, Cnestis ferruginea, Entandrophragma utile, Hura crepitans, Lonchocarpus griffoneonus, Rauvolfia vomitoria, Senna siamea, Tamarindus indica, Tectona grandis and Treculia africana had the least frequency (25% each). For the density, Nauclea diderichii had the value of 250±15.30 st/ha. In the botanic garden, Ageratum houstonianum, Alchornea cordifolia, Chromolaena ordorata and Croton hirtus had the highest frequency (100%) while Allamanda cathartica, Asystasia gangetica, Bambusa vulgaris, Caladium bicolor, Centrosema virginianum, Cnestis ferruginea, Culcasia scandens, Cyathula prostrata, Desmodium scorpiurus, Emilia sonchifolia, Heliconia psittacorum, Ipomea involucrata, Lagenaria sphaerica, Mimosa pudica, Nephrolepis bisserata, Panicum sp., Pentaclethra macrophylla, Plumeria rubra, Polyalthia longifolia, Pteridium aquilinum, Scoparia dulcis, Senna siamea, Sesamum radiatum and Sida acuta had the least frequency (33.33%). The vegetation of both sites indicated variation in composition of trees, shrubs, herbs, climbers and ferns. These heterogeneities may be a pointer to their varying adaptation levels and differential responses of plant species to pedological and anthropogenic influences.

Antidyslipidemic Effect of Diherbal mixture of Pteridium Aquilinum and Caesalpinia bonducella in Albino Rats

Pteridium aquilinum and Caesalpinia bonducella are plants commonly used in the management of various ailments in Nigerian folk medicine. Each of them have been found to possess antioxidant and anti-inflammatory properties that can help in maintaining cardiovascular health. In the present study, the effect of the herbal mixture on the lipid profile of albino rats was investigated. A total of twenty albino rats were used in the study. These rats were randomly distributed into 5 groups of 4 rats per group. The rats were allowed to acclimatize for ten days prior to treatment. Rats in group 1 (control) were kept on water and feed. While rats in groups 2, 3, 4 and 5 were treated with 200, 400, 600 and 800mg/kg bwt. of the di-herbal mixture respectively. The treatments lasted for 21 days. Twenty four hours after treatment, the rats were sacrificed. Blood samples collected and prepared for lipid profile. The following parameters: total cholesterol (TC), High-density Lipoprotein (HDL), Low-density lipoprotein (LDL) and triglycerides (TG) were evaluated by standard methods. Results showed that the di-herbal mixture exhibited a dose-dependent reduction in Total cholesterol, LDL cholesterol and Triglyceride. For instance, the control rats had a total cholesterol value of 91.28± 3.54mg/dl. When the herbal mixture was introduced at the dose of 200mgkg bwt, cholesterol value reduced to 90.28±3.77mg/dl. Dose-dependent increments in HDL Cholesterol levels were however, recorded. For instance, the control rats had a HDL Cholesterol value of 32.28 ± 1.81mg/dl. When the herbal sample was given at the initial dose of 200mg/kg bwt, HDL Cholesterol level increased to 34.21 ± 1.72mg/dl. When the extract dose was further increased to 400mg/kg bwt. HDL Cholesterol level was found to be 34.61± 2.10mg/dl. The conclusion was thus drawn that the sample has the potency of maintaining healthy levels of the cardiac function parameters investigated.

Network pharmacology analysis of the renal protective effects of bracken (Pteridium aquilinum) using experimental data obtained in an avian (quail) hyperuricemia model.

To investigate the nephroprotective potential of orally administered bracken Pteridium aquilinum extract against renal damage in quails, induced by a high-purine diet, to form a foundation for subsequent clinical studies and applications. A mass spectrometry analysis was conducted on the pteridophyte subjected to steam explosion. Network pharmacological methods were then utilized to pinpoint shared targets and pathways, which suggested that Pteridium aquilinum has a capability to counteract renal injury. A total of 48 specific-pathogen-free (SPF) "Difaku" quails were selected and segregated into six distinct groups. The control group received a standard diet, whereas the other groups were fed a high-purine diet. Beginning on day 14, each group was subjected to designated therapeutic measures. The study continued for 40 days, after which relevant biological markers were assessed. Active compound peaks from the steam-exploded Pteridium aquilinum were isolated. Subsequently, 101 targets and several pathways associated with renoprotective effects were discerned, indicating that the Pteridium aquilinum achieves its nephroprotective function through comprehensive regulatory mechanisms. The high-purine diet successfully induced hyperuricemia in the quails, resulting in renal impairment. Following intervention with varied Pteridium aquilinum dosages, renal protective outcomes were evident, though xanthine oxidase activity remained unaffected. Histological analyses demonstrated a notable decrease in renal lesion dimensions post-intervention. The steam-exploded bracken Pteridium aquilinum may provide nephroprotective benefits against hyperuricemia-induced renal damage in quails through comprehensive regulatory processes. This highlights the Pteridium aquilinum's potential as an innovative nephroprotective therapeutic and dietary solution, presenting a promising avenue for hyperuricemia and renal damage treatment and prevention.

Anti-Inflammatory Activity of Fern Pteridium aquilinum Ethanol Extract Gel on Mice (Mus musculus) Incision Wounds

The utilization of natural resources around the community is one of the alternative anti-inflammatory medications. One of the several studies on this area reported that commonly people use Pteridium aquilinum leaves to heal wound instead of commercial gel medications. The research aimed to determine the activity and it effective dose of Pteridium aquilinum ethanol extract gel as an anti-inflammatory. The ethanol extract of Pteridium aquilinum was formulated in a gel with varying dosage concentrations of 1%, 1.5%, and 3% for 2 times applied a day in 14 days, with the incision wounds without fern ethanol extract gel as negative control and incision wound was treated with commercially as positive control. Observation on the wound length and the injured tissue histology of mice incision wound carried out on 3, 5, 7, and 14 days of treatment. The results prove that fern ethanol extract gel formula has anti-inflammatory activity on mice incision wound. Wound healing indicated by the closure of the wound on the skin. Based on the results can be concluded that Pteridium aquilinum ethanol extract has anti-inflammatory and heals mice incision wound affectively in 14 days with the best dosage concentration of 3%.

Variation in hazel dormouse (Muscardinus avellanarius) presence in hedge and scrub habitats

Abstract Habitat restoration at a landscape scale is key to reversing the loss of biodiversity arising from habitat destruction. In landscapes that are intensively used by people, such as for agriculture, valuable restoration efforts might be applied not just to ‘prime’ habitats that are known to have strong associations with target species, but also to ‘sub‐prime’ habitats that might nevertheless provide sufficient resources to support populations. Hazel dormouse (Muscardinus avellanarius) populations are in chronic decline in the UK. The species is typically associated with broadleaf woodland but restoration of this habitat at scale in agricultural landscapes is difficult. Other habitats used by dormice might, therefore, provide opportunities for restoration. We investigated the use by hazel dormice of hedgerow and scrub habitats in southwest England. From June–November 2022, using footprint‐recording tunnels, we surveyed 38 hedges and 21 scrub patches in the vicinity of 18 sites known to contain established dormouse populations. We found that dormice were frequently present in scrub (9.3 detections per 100 tunnel checks, 95% confidence interval 6.6–12.0) and less frequently in hedges (4.5 detections, 95% CI 3.2–5.8). In scrub patches, dormice were present more frequently as the abundance of dormice in the closest population increased, and less frequently where bracken (Pteridium aquilinum) was dominant. In hedges, dormice were detected more frequently where there was abundant hazel (Corylus avellana) and honeysuckle (Lonicera periclymenum), as frequency of intersections with other hedges increased, and where an earthen bank was not present. Understanding hazel dormouse association with a wide range of habitats, particularly scrub, offers more opportunities for habitat restoration as part of species conservation strategies.

Influence of Fly Ash on Soil Properties and Vegetation of Fresh Coniferous Forest during Long-Term Observation

Fly ashes produced in huge amounts during coal combustion requires proper management. The purpose of this study was to determine the impact of fly ash from burning hard coal used in large doses (250, 500, 1000 and 2000 t ha−1) on soil properties and vegetation of fresh mixed coniferous forest within 43 years from the ash application. The experiment was established in the Podzols in the forest habitat of Czułów, Katowice Forest district, Upper Silesia, Poland. Eight tree species were planted in ridges created by ploughing: Pinus sylvestris, P. nigra, Larix decidua, Betula pendula, Quercus robur, Q., Acer pseudoplatanus and Fagus sylvatica. The changes in soil morphology caused significant transformations in the physical and chemical properties of the soil such as soil texture, pH, macronutrients (P, K and Mg) content and C:N ratio. Increasing of ash doses changed the granulometric composition of the soil levels from loamy sand (250 t/ha−1) to silt loam (2000 t ha−1). Initially, the acidic Podzols were alkalized under the influence of the fly ash and then acidified, possibly due to the impact of accumulated litter layers, and the reaction of organic soil horizons changed from strongly acidic (250–1000 t ha−1) to alkalis (2000 t/ha−1). The macronutrients content increased in proportion to the fly ash dose, but the subsequent acidification resulted in a gradual decrease in the macronutrients share in the soil layers. The value of the C:N ratio grew after the ash application and then it gradually reduced, even by half. The transformations of soil horizons’ properties also increased the capacity of the soil sorption complex (CEC). All these processes led to a change in the trophic status of the habitat expressed by the soil habitat index (SIG) and the initial coniferous forest site can be classified as a mixed forest habitat even with the lowest ash dose used. The composition of plant communities developed forty years after the ash application was similar at the lower ash doses and the most frequent and abundant tree species were L. decidua, P. nigra and P. silvestris. B. pendula was previously co-dominant, but it was eliminated from the tree stands during the experiment. Planted trees characteristic of late stages of succession, such as Q. robur, Q. rubra, F. sylvatica and A. pseudoplatanus either did not survive or remained in very low quantities. The herb and moss layers developed in the process of spontaneous colonization, and together with the trees led to phytostabilisation of the bare substrates. After acidification of the topsoil horizons, the herb layers consisted mostly of coniferous, mixed, and deciduous forest species, and the most frequent or abundant were Lysimachia europea and Pteridium aquilinum. The moss layers were represented by coniferous forest flora. At the ash dose of 2000 t ha−1, Tilia cordata settled in one of the seral stages of spontaneous succession and this species dominated in the community and formed a dense tree stand. After the soil acidification, a shift from calcicole to calcifuge plant strategy took place among species of the herbaceous layer. The transformations of plant communities’ composition occurred in relation to changes in the soil properties.

Assessing Environmental Safety Risks associated with Ptaquiloside: A Rapidly Leaching Glucoside from Bracken Ferns

Ptaquiloside (PTA), a glucoside found in common tropical bracken ferns like Pteridium aquilinum, possesses genotoxic and DNA-damaging properties. Its water-solubility makes it susceptible to rapid leaching during rainfall, resulting in its presence in groundwater. PTA's DNA alkylation ability contributes significantly to tumorigenesis, substantiating its carcinogenic potential in animals including humans. Its presence has been confirmed not only in groundwater but also in meat and milk. The unique leaching behavior of PTA, along with evidence of multiple mechanisms leading to cellular mutations, warrants further attention. Research is needed to enhance the isolation and purification of PTA from samples. While the current understanding points to DNA alkylation as the primary mechanism of action, emerging studies suggest potential alternate mechanisms that remain elusive.

Fungal endophyte Cryptomycina pteridis (Rebent.) Syd. on the native fern Pteridium aquilinum (L.) Kuhn in Poland

Cryptomycina pteridis (Ascomycota, class Sordariomycetes) is a highly host-specific fungus, infecting only a native, fern Pteridium aquilinum. This endophyte is usually overlooked, although it is easy to recognise due to its characteristic symptoms on bracken fern fronds, especially advanced narrowing and shrivelling of pinnae and pinnules. Infested plants have pinnae and pinnules curling upwards, and dark stromata along the veins on the undersides of pinnules. The fungus is an obligate systemic endophyte, which disturbs fern growth. The paper presents some old and new records of C. pteridis in Poland.

Distribution and migration of uranium, chromium, and accompanying metal(loid)s in soil-plants system around a uranium hydrometallurgical area

The extraction and utilization of uranium (U) ores have led to the release of significant amounts of potentially toxic metal(loid)s (PTMs) into the environment, constituting a grave threat to the ecosystem. However, research on the distribution and migration mechanism of U, chromium (Cr), and their accompanying PTMs in soil-plant system around U hydrometallurgical area remains insufficient and poorly understood. Herein, the distribution, migration, and risk level of PTMs were evaluated in soil and plant samples around U hydrometallurgical area, Northern Guangdong, China. The results demonstrated that the maximum content of U and Cr found in the analyzed soils were up to 84.2 and 238.9 mg/kg, respectively. These values far exceed the soil background values in China and other countries. The highest content of U (53.6 mg/kg) was detected in Colocasia antiquorum Schott, and the highest content of Cr (349.5 mg/kg) was observed in Pteridium aquilinum, both of which were enriched in their roots. The risk assessment of PTMs demonstrated that the study area suffered from severe pollution (PN > 3), especially from U, Cr, Th, and As, suggesting the non-negligible anthropogenic impacts. Hence, in light of the significant ecological hazard posed by the U hydrometallurgical area, it is imperative to implement appropriate restoration measures to ensure the human health and maintain the stability of the ecosystem.

Three new flavonoid glycosides isolated from Pteridium aquilinum

Three new flavonoid glycosides, (S)-4′,6,8-trihydroxyflavanone-7-C-glucoside (1), (R)-4′,6,8- trihydroxyflavanone-7-C-glucoside (2) and distenin-7-O-β-D-glucoside (3), along with nine known flavonoids (4-12) were isolated from the aerial of Pteridium acquilinum. Their structures were elucidated by the analysis of spectroscopy data and their comparison with the reported values. The two C-glycosyl flavanones (1 and 2), were isolated from this specie, which might be chemotaxonomic markers of this specie. In addition, three new flavonoids were preliminarily examined for their anti-inflammatory activity. Compounds 1-3 inhibited the NF-κB induction by 46.3%, 59.6% and 29.2%, respectively.

Health and Environmental Hazards of the Toxic Pteridium aquilinum (L.) Kuhn (Bracken Fern).

Bracken fern (Pteridium aquilinum (L.) Kuhn) is ubiquitous and acts as a cosmopolitan weed in pastures and similar environments. Despite its historical uses, it presents risks due to toxicity. This study, conducted in the second half of 2023, aimed to assess the environmental and health hazards of P. aquilinum, primarily focusing on its carcinogenic compound, ptaquiloside. The literature was comprehensively reviewed using diverse databases, including PubMed, Web of Science, Scopus, and Google Scholar. Information was synthesized from original research articles, meta-analyses, systematic reviews, and relevant animal studies. Animals grazing on bracken fern face annual production losses due to toxin exposure. The substantial impact on biodiversity, animal health, and human well-being arises from the presence of ptaquiloside and related compounds in milk, meat, and water, along with the increasing global prevalence of P. aquilinum and its swift colonization in acidic soil and fire-damaged areas. The objectives were to identify major bioactive compounds and explore their effects at molecular, cellular, pathological, and population levels. Various cooking techniques were considered to mitigate toxin exposure, although complete elimination remains unattainable. Therefore, the findings emphasize the need for cautious consumption. In conclusion, continued research is necessary to better understand and manage its environmental and health implications.

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Palynological study of archaeometallurgical artefacts from the Late Bronze Age copper smelting sites (Georgia): First results

This article focuses on the palynological (pollen and non-pollen palynomorphs) study of material found with artefacts from Late Bronze Age archaeometallurgical sites in the Lechkhumi area of the mountainous south-west Caucasus region of ancient Colchis. The analysis of organic residues recovered from voids in slag and crucible fragments have revealed an abundance of pollen and spores of diverse plant taxa. Many non-palynological palynomorphs were also found. In total, more than 50 palynomorphs were identified. It was observed that the chemical composition of the copper smelting slag fragments has contributed to the good preservation of the pollen grains, though detailed chemical analyses and experiments are needed. The spectrum from slag includes taxa that are more poorly preserved in sediments, including soil. This preservation undoubtedly makes palynological research of slag residues promising in the future. The range of fossilized plants and spores recovered proves that during the Late Bronze Age in Lechkhumi, forests dominated by chestnut (Castanea sativa) occupied a much larger area than today. Other thermophilic trees, such as zelkva (Zelkova carpinifolia), oak (Quercus), lime (Tilia), and hornbeam (Carpinus betulus) were also present. Thermophilic ferns thrived in the undergrowth as well. In the 13th–9th centuries BC, the existence of warmer climatic conditions in Lechkhumi compared to that we have now is additionally confirmed by the presence of freshwater thermophilic algae Pseudoschizaea, Spirogyra and other Zygnemataceae found in the spectra. Spores of bracken fern (Pteridium aquilinum) and fungus Ustulina most probably reflect felling and human exploitation of the woodland in the close neighbourhood of the site. Comparison of palynological and wood charcoal analyses has demonstrated that the metallurgists of that time used the nearby woods as a source of fuel. Thanks to favourable climatic conditions, beside copper smelting some small-scale agricultural activities were performed which was visible in the composition of herbaceous plant taxa.

Exogenous preculture with sucrose and abscisic acid improves post-cryopreservation survival of eastern bracken fern gametophytes

Cryopreservation is an important technique used in the conservation of various plant tissues. This study proposes a cryopreservation method for the long-term conservation of eastern bracken fern gametophytes (Pteridium aquilinum var. latiusculum). Encapsulation–dehydration of the gametophytes was performed, and the exogenous sucrose and abscisic acid (ABA) preculture conditions were investigated. Gametophytes are sensitive to dehydration and drying, and the following treatment conditions were applied: encapsulation by alginate containing 0.75 M sucrose, 18-h loading treatment with 0.75 M sucrose, and 6-h drying treatment. The survival rate following cryopreservation was determined. The water content of < 27.5% in the alginate beads after dehydration and drying was found to be appropriate for ensuring survival. Additionally, performing an exogenous sucrose and ABA preculture was essential before encapsulation to achieve a survival of ≥ 90%. The high stress induced by cryopreservation and exogenous preculture regulated the expression of PaSuSy, PaLEA14, and PaABI1b and the endogenous ABA content. In eastern bracken gametophytes, ABI1 appears to be a negative regulator of ABA signaling. These results indicate that the encapsulation–dehydration method is effective for the long-term conservation of eastern bracken fern gametophytes, and exogenous preculture alleviates abiotic stress and increases the survival rate.

Modelling landscape vulnerability to the Bracken fern (Pteridium aquilinum) invasion in a remnant urban Sandstone Sourveldt grassland ecosystem

The Bracken fern (Pteridium aquilinum) is one of the world's most pervasive alien invasive plants, exerting adverse effects on the sustainability and balance of remnant urban green ecosystems and thereby threatening the provision of valuable ecological goods and services in urban landscapes. To identify vulnerable landscapes and future distribution of the fern, this study aimed to model landscape vulnerability to the Bracken fern invasion using bio-physical, climatic, and remotely sensed data using Maxent species distribution model. Furthermore, the study sought to evaluate the value of variable selection on Maxent's modelling performance. Vulnerability to invasion was modelled based on four scenarios of different bio-climatic, physical and remotely sensed data inputs and model performance assessed using the area under the receiver operator characteristic curve (AUC). The results show that Model 1 (topographic variables) and Model 2 (topographic variables and Sentinel-2 spectral bands) predicted the western part of the eThekwini Municipal as highly suitable for the Bracken fern invasion, while Model 3 (topographic and bio-climatic variables) and Model 4 (topographic variables, Sentinel-2 spectral bands and bio-climatic variables), i.e., all variables predicted the central and western parts of the area as highly vulnerable to the Bracken fern invasion. Results also showed that elevation and rainfall wettest month (Bio13) were the most influential variables in determining the potential spread of the Bracken fern invasion and the model built using solely topographic and all the variables had the lowest (AUC of 0.895) and highest (AUC of 0.978) performance. The findings of this study are valuable to planning conservation initiatives in the often-vulnerable urban green ecology and managing invasive species in the remnant urban green spaces.

Habitat and other environmental correlates of the decline of breeding Whinchats Saxicola rubetra in the UK since the mid-1990s

ABSTRACT Capsule Declines in Whinchat Saxicola rubetra breeding abundance in the UK vary with habitat and other environmental conditions. Aims To test for associations between changes in Whinchat abundance between 1994 and 2018 and measures of habitat and environmental conditions on UK breeding sites. Methods Whinchat counts collected through a national monitoring scheme were tested at coarse 1 km2 square and finer 200 m transect scales against habitat data collected in 2017/2018, plus remotely sensed data to test for long-term change. Results At the 1 km2 square scale, mean change in Whinchat abundance was more negative where woodland occurred more frequently, and at more northerly latitudes. Rates of decline were lower where there was greater cover of Purple Moor-grass Molinia caerulea and non-bracken vegetation height was taller. At the finer 200 m transect scale, more closely resembling Whinchat territory size, rates of decline were greatest in areas dominated by human sites, woodland, and enclosed farmland, compared to unenclosed open semi-natural habitats; however, within the latter category, declines were lower in grass-dominated relative to heather-dominated habitats. Rates of decline were also lower closer to valley bottoms, with greater Bracken Pteridium aquilinum cover and at mid-elevations (300 m), and greatest where there was greater cover of bare ground and trees, and moderate cover of grasses (excluding Molinia and Lolium spp.). The strength of the finer-scale associations varied between dominant habitat types. Whinchat abundance was lower where a remotely sensed index of vegetation productivity (normalized difference vegetation index [NDVI]) was higher, and abundance change more negative where temporal increases in NDVI were greater. Conclusion Unenclosed semi-natural grassland showed the lowest rate of decline and offers the best opportunities to conserve Whinchats. Woodland expansion is likely to have a detrimental impact on breeding Whinchats. Future research should investigate how important habitat and environmental correlates influence key demographic rates affecting recruitment.