Growth Formation Research Articles

Assessing the reliability of woody vegetation structural characterisation from UAV-LS in a tropical savanna

Terrestrial laser scanning (TLS) represents the gold standard in remote quantification of woody vegetation structure and volume, but is costly and time consuming to acquire. TLS data is typically collected at spatial scales of 1 ha or smaller, which limits its suitability for representing heterogeneous landscapes, and for training and validating satellite-based models which are needed for larger area monitoring. Advances in unoccupied aerial vehicle laser scanning (UAV-LS) sensors have recently narrowed the gap in quality between what TLS delivers and what can be acquired over larger areas from UAV platforms. We tested how well new nadir-forward–backward (NFB) UAV-LS technology can capture the structure of individual trees in a tropical savanna setting with a diversity of tree sizes and growth forms. UAV-LS data was acquired with a RIEGL VUX-120 LiDAR sensor mounted on a Acecore NOA hexacopter. Reference data was obtained with a RIEGL VZ-2000i TLS scanner using a multi-scan approach. Point clouds were segmented into individual trees and volumetrically reconstructed with RayCloudTools (RCT). We found no statistical difference between UAV-LS and TLS derived estimates of tree height, canopy cover, diameter, and wood volume. Mean tree height and DBH derived from UAV-LS were within 3% of the TLS estimate, and there was less than 1% deviation in stand wood volume. Our findings ease the advancements on the detailed monitoring of open forests, potentially achieving large-scale mapping and multi-temporal investigations. The open structure of savanna systems is well suited to UAV-LS sensing, but more research is needed across diverse ecosystems to understand the generality of these findings in landscapes with greater canopy closure or complex understorey conditions.

Loss of taxonomic and functional diversity and decrease in primary productivity with nitrogen enrichment after a long-term release from grazing in an alpine grassland

Moderate grazing can sustain high species diversity and productivity. However, nitrogen enrichment often reduces species richness while promoting primary productivity, which contradicts the traditional understanding of the positive effect of plant diversity on productivity. Whether the responses of diversity and productivity to N enrichment on a long-term scale conform to those on short-term scale. Furthermore, chemical N forms may alter species richness or functional diversity because of species preferences for different N forms. We used data from a 19-year field experiment with manipulated livestock exclusion and the addition of N in three chemical forms (ammonium, nitrate, and their mixture) in an alpine grassland to test their effects on diversity and aboveground productivity. Productivity in no N without grazing plots (Ctr) initially increased by 66 % during the first five years after livestock exclusion (0.53 kg m−2), following which productivity fluctuated at a similar level as that in winter livestock grazing (0.32 kg m−2) for the next eight years and ultimately decreased to the level of 0.24 kg m−2, below that in Gr with continued species loss. The addition of N forms in grazing exclusion increased productivity, accompanied by the loss of rare species in the first five years. Afterward, productivity decreased, and it took longer than the control to reach the same level as that seen in winter grazing. Then, productivity continued to decline with more species loss. The functional diversity of leaf traits and plant growth forms decreased. Ammonium favored grasses with guerrilla and phalanx rhizomes, nitrate favored sedges and forbs with guerrilla rhizomes, and ammonium-nitrate sustained a relatively higher diversity of plant growth forms. Our general conclusion is that grasslands with moderate grazing are beneficial for sustaining diverse species and high productivity. N enrichment reduces plant diversity, and the increase in productivity driven by N is only transitional, as productivity declines in the long run, with continuous N addition.

Soil seed bank resilience in passively restored endangered Sand Fynbos following a century of pine plantations

Societal Impact StatementEcosystems are rapidly being transformed, pushing us towards irreversible losses and even extinctions. The Kunming‐Montreal Global Biodiversity Framework aims to curb biodiversity decline. An intriguing solution lies in seed banks—where plants store seeds in the soil. Restoration efforts can revive lost ecosystems by leveraging these seed banks. In the fynbos of South Africa, this study found that it is possible to bring back ecosystems that were lost as long ago as 100 years if conditions are right. Managers can achieve best results by applying a dry season prescribed burn following removal of the driver of degradation (e.g. pine plantations or invasions).Summary Soil‐stored seed banks are a critical evolutionary strategy for plants as they can stabilize population dynamics in response to environmental fluctuations such as droughts and natural disturbances such as fires, thus improving ecosystem resilience. This study aimed to assess resilience during the first restoration cycle of endangered Sand Fynbos following pine harvesting and a prescribed burn in South Africa. We compared above ground populations and soil‐stored seed bank composition and focused on six perennial fynbos focal species in five 1 m2 plots. All six species are obligate reseeders with soil‐stored seed banks but represent a variety of important fynbos growth forms and seed types. We found that native soil‐seed bank density following over a century of plantation forestry and 10 years after the first fynbos restoration burn was comparable to, or exceeded, densities measured in other fynbos studies, especially seed banks of alien‐invaded fynbos ecosystems. The early years following pine harvesting and a restoration burn likely provide a pest‐ and predator‐free window of opportunity in which plants may re‐establish and flourish. Our results show that even for old forestry plantation areas, ecological restoration to the historic vegetation community is feasible, where there is retained seed bank resilience, through a combination of passive and active restoration methods. Ecological restoration in cases where soil seed banks persist is therefore a viable and critically important method to attain 30% conservation of terrestrial land in ecosystems with less than 30% remaining, as part of the Kunming‐Montreal Global Biodiversity Framework.

Assessing Coral Reef Health in Northern Waters of Penata Besar Island West Kalimantan

Penata Besar Island is designated as one of the Coastal and Small Island Conservation Areas (KKP3K) in West Kalimantan, is a critical site for conserving coral reefs and reef fish. Currently, global climate change and anthropogenic activities have exacerbated coral reef bleaching worldwide. In the context of escalating global climate change and human-induced threats, this study evaluates the health condition of coral reefs in the northern waters of Penata Besar Island, Bengkayang Regency. An exploratory approach was employed, utilizing the Line Intercept Transect (LIT) method across four stations at two distinct depths (2-3 m and 5-6 m). The results revealed that coral cover varied with depth. At a depth of 2-3 m, live coral coverage was between 51.2% and 62.4%, classified as good, while at 5-6 m, coverage ranged from 30.4% to 49.4%, categorized as fair. Coral Massive (CM) was the predominant growth form observed. The diversity index (H') ranged from low to medium, the Evennes index (E) from medium to high, and the dominance index (C) was categorized as low. These findings highlight the varying health of coral reefs in different depths and provide a basis and essential insights for targeted conservation efforts.

Distinct interspecies thermal resistance strategies exhibited by euplanktonic, tychoplanktonic and benthic diatoms under marine heatwaves

Extreme climate events, such as marine heatwaves (MHWs), are expected to occur more frequently and intensely in the future, resulting in a substantial impact on marine life. The way that diatoms respond to MHWs may have crucial effects on global primary production and biogeochemical cycles. Euplanktonic diatoms appear to benefit from MHWs directly, but this phenomenon needs an explanation. As concerns tychoplanktonic and benthic diatoms, no studies have been addressed on their thermal response strategies. To address this, we investigated the responses and underlying mechanisms of three typical growth forms of diatoms, Pseudo-nitzschia multiseries (euplanktonic), Paralia guyana (tychoplanktonic) and Navicula avium (benthic), under heat stress by combining a growth experiment with transcriptomic analysis. Our results showed that the physiological responses of diatoms to MHWs and underlying molecular mechanisms are largely related to their growth forms. The euplanktonic diatom was first depressed, but then had a distinct increase in the growth rate accompanied by inducing zeatin and unsaturated fatty acid biosynthesis and repressing substance assimilation and energy metabolism. Contrarily, the benthic diatom showed elevated substance and energy demands for macromolecules accumulation by reducing cell division and increasing photosynthesis and nitrogen assimilation. The tychoplanktonic diatom exhibited higher physiological plasticity to maintain growth and cellular homeostasis. Our results indicate the increased rate of cell division in euplanktonic diatoms under heat stress is likely an emergency response strategy promoting diatom dispersal for survival, but at the cost of disturbances of metabolic balance.

Exploring functional traits of Canga liverworts along different mesohabitats: insights from a threatened ecosystem and underexplored plants in Brazil

ABSTRACT Introduction Brazil’s Canga ecosystems, characterised by ironstone outcrops, face increasing threats from mining activities. Predominantly located in Minas Gerais’ Iron Quadrangle region, these ecosystems are notable for their diversity of bryophytes, especially liverworts. Despite their ecological significance, comprehensive studies on liverworts in Cangas are scarce, leaving a gap in understanding their responses to environmental factors. Methods We analysed the organisation of life traits in liverworts across three distinct Canga mesohabitats: exposed areas, shrub associations and tree associations. We hypothesised that these life traits are distinctly structured according to the mesohabitat, ranging from exposed to shaded. Key results Our survey recorded 714 specimens, encompassing 73 species and 12 families, with Lejeuneaceae, Frullaniaceae and Metzgeriaceae being the most represented families. Frullania brasiliensis Raddi emerged as the most abundant species. Mesohabitats differed primarily in terms of solar radiation and temperature. Life traits of communities did not correlate with mesohabitat types. Instead, liverworts formed five functional groups based on family, asexual reproduction, growth forms, spore germination types and leaf colour. Conclusions This study highlights the ecological heterogeneity and significant liverwort diversity of Brazilian Cangas, emphasising the importance of diverse strategies in population maintenance. Prioritising the functional diversity of liverworts is essential in conservation strategies for Cangas, focusing on preserving diverse mesohabitats.

Weeds Ethnobotanical Studies: Use of Midicinal Plant as A Self-Medication by The Community of Bayan Traditional Village, North Lombok District, West Nusa Tenggara

The study aimed to describe and inventory the diversity of medicinal plant species used by the people of Bayan traditional village. The study used descriptive methods and data collection using survey techniques and semi-structured interviews. The survey location was determined by random sampling in the yards of the Sasak, Balinese, and Javanese tribes, each with three sampling points. Parameters observed were population characteristics, morphology, and how to use medicinal plants. The results showed that medicinal plants were found in the yards of the Javanese tribe in 50 species with 1197 individuals, the Balinese tribe in 47 species with 974 individuals, and the Sasak tribe in 35 species with 548 individuals. The dominant species with the highest abundance index were star gooseberry, agathi, turmeric, ginger, white tumeric, halviva, cat's whiskers, and noni. The medicinal plant species found have been used to treat 28 kinds of diseases. The form of plant life that is widely used for medicine is herbaceous. The part of the plant organ that is most widely used for traditional medicine raw materials is the leaf. The most common way to process medicinal plants is by boiling them, then drinking boiled water, finely grinding them, and drinking the juice.

Divergent trajectories of regeneration in early-successional forests after logging and wildfire.

Increases in forest disturbances have altered global forest demography rates, with many regions now characterized by extensive areas of early-successional forest. Heterogeneity in the structure, diversity, and composition of early-successional forests influence their inherent ecological values from immediately following disturbance to later successional stages, including values for biodiversity and carbon storage. Here, using 14 years of longitudinal data, we describe patterns in the structure, richness, and composition of early-successional forests subject to one of three different disturbance types: (1) clearcut logging followed by slash burn, (2) severe wildfire followed by salvage logging, and (3) severe wildfire only, in the Mountain Ash (Eucalyptus regnans) and Alpine Ash (Eucalyptus delegatensis) forests of southeastern Australia. We also documented the influence of disturbance intervals (short, medium, and long) on early-successional forests. Our analyses revealed several key differences between forests that regenerated from wildfire versus two different anthropogenic perturbations. Most ash-type plant communities were resilient to wildfire within historical fire-regimes (75-150 years), exhibiting temporal trends of recovery in plant structure, richness, and composition within the first decade. In contrast, the richness, occurrence, and abundance of some plant lifeforms and life history traits were negatively associated with clearcut logging and salvage logging, relative to forests disturbed by wildfire alone. These included resprouting species, such as tree ferns and ground ferns. However, Acacia spp. and shrubs were more abundant after clearcut logging. Our findings also provide evidence of the pronounced negative impact of salvage logging on early-successional plant communities, relative to that of both clearcut logging and wildfire. Notably, plant richness declined for over a decade after salvage logging, rather than increased as occurred following other disturbance types. Early-successional forests provide the template for the stand structure and composition of mature forests. Therefore, altered patterns of recovery with different disturbance types will likely shape the structure and function of later-successional stages. Predicted increases in wildfire will increase the generation of early-successional forests and subsequent salvage logging. Therefore, it is pertinent that management consider how different disturbance types can produce alternate states of forest composition and structure early in succession, and the implications for mature stands.

An enemy's enemy is an ally: Competitive indirect interactions mediate coexistence of trees, grasses, and subshrubs in neotropical savanna

AbstractSavannas are complex ecosystems where multiple growth forms, including grasses, trees, and subshrubs, coexist through intricate ecological interactions. Understanding the mechanisms that promote this coexistence is key to conserving savanna biodiversity. This study investigated the effects of grass competition on the survival and growth of trees and subshrubs, as well as the interactions between these two growth forms. Using three species of trees and three species of subshrubs, we conducted a greenhouse experiment to assess how competition between trees and subshrubs is influenced by the presence of grass. We found that grass competition significantly reduced the survival of tree seedlings, while subshrubs were unaffected. When trees and subshrubs competed directly, subshrub biomass was reduced, but only in the absence of grass. Tree seedling biomass was not affected by subshrubs, but was negatively impacted by grass in the absence of subshrubs. Both root and stem biomass of trees and subshrubs were reduced by grass competition; however, this effect was mitigated when grasses, subshrubs, and trees competed simultaneously. These results indicate that when grasses, subshrubs, and trees compete together, the intensity of competition is reduced, promoting coexistence and contributing to the balance of growth forms in savanna ecosystems. While fire is an important factor in savanna dynamics, our study emphasizes the critical role of competition in maintaining this balance. Future studies should explore how fire and competition interact to further our understanding of biodiversity and ecosystem function in Neotropical savannas.Abstract in Portuguese is available with online material.

A geospatial dataset of lichen key attributes in the Earth's three poles.

In the Antarctic, Arctic, and Tibetan Plateau-recognized as the Earth's three poles characterized by extremely harsh environments-lichens prevail in the ecosystem and play crucial roles as pioneer species. Despite their importance, studies investigating the spatial distribution patterns of lichen attributes are scarce due to a lack of appropriate datasets. To bridge this gap and enhance our understanding of the growth preferences of lichens in these areas, here we present a geospatial dataset encompassing key attributes of lichens, such as color type and growth form, for over 2800 lichen species and 170,000 in-situ lichen records. The dataset facilitates the creation of the first spatial distribution map illustrating the variation of lichen attributes across different latitudes and longitudes. This can serve as a foundational resource for studies on the relationship between lichen types and their growing environment, which is a vital scientific question in the ecology domain. Additionally, it can contribute to the development of specialized remote sensing technique tailored for lichen monitoring, which is currently lacking.

Widely acclaimed but poorly named: Phylogeny and systematics of the African daisy genus Dimorphotheca (Asteraceae, Calenduleae)

AbstractPhylogenetic relationships in the South African daisy genus Dimorphotheca have long been uncertain, with the taxonomy of the genus relying on a few morphological traits, most prominently capitulum sexual system (e.g., cypsela type) and ray colour, which may not be evolutionarily conserved. Here we present the first well‐sampled molecular phylogeny of Dimorphotheca, based on nuclear ribosomal (ITS, ETS) and plastid trnL‐trnF region DNA sequences from multiple accessions per species. Although the relationships suggested by these markers are broadly congruent, we do find some instances of incongruence which we resolve using a combined decomposition and deletion approach. Using our best estimate of phylogenetic relationships, we reconstruct the evolution of capitulum fertility and ray colour to assess the evolutionary conservatism of these traits and their taxonomic utility. We find support for the monophyly of Dimorphotheca, excluding the recently segregated Osteospermum polypterum, and our data thus support the modern, enlarged circumscription of the genus incorporating the former genus Castalis and Osteospermum sect. Acanthotheca and O. sect. Blaxium. Major subclades within Dimorphotheca are largely cohesive in terms of geographic distribution and morphological traits such as growth form and cypsela structure. While many species are resolved as monophyletic, the polyphyly of a few species suggests a need for taxonomic re‐evaluation. On the basis of both morphological and molecular data, we describe one new species, and elevate one variety to species level. A full taxonomic key to the enlarged genus is presented for the first time. Ancestral reconstructions show that capitulum sexual system and ray lamina colour are not evolutionarily conserved and that neither can therefore be used to delimit major lineages within Dimorphotheca. While our findings resolve some taxonomic problems, they also highlight the need for further species‐level taxonomic work on Dimorphotheca.

The Influence of Digital Economic Growth and Productive Work Force Toward Human Development Index in Indonesia Viewed from a Maqashid Sharia Perspective

Introduction: Community productivity is critical in maintaining quality of life to avoid disasters. The use of digital technology in the economic aspect has also provided opportunities for people far from the market to earn income to meet their living needs. Objective: The research problem is formulated as follows: What is the influence of digital economic growth and productive labor on the Human Development Index in Indonesia in 2018-2022, both partially and simultaneously, and how is this viewed from a maqasid syariah perspective?Method: This research is presented as five-year time series data and analyzed using quantitative descriptive methods and multiple linear regression analysis, using Eviews 10 as an analytical tool. The sampling technique used was purposive sampling, with sample criteria in the form of digital economic growth, productive workforce, and data during the 2018-2022 period. Result: The digital economic growth variable partially has a negative and insignificant effect on the Human Development Index. Meanwhile, the productive labor variable positively and significantly affects the Human Development Index. Simultaneously, the growth of the digital economy and productive workforce has had a positive and significant effect on the Human Development Index in Indonesia in 2018-2022. From a maqasid syariah perspective, digital economic activities are permitted if no arguments prohibit them. Implication: This research provides valuable insights that can influence how we view and approach digital economic growth and productive labor in Indonesia's human development context. By considering these impacts, various parties can optimize their strategies to advance people's quality of life more effectively.

Pattern of Sprawl Development Along the Abuja–Keffi Highway Corridor in The North Central Nigeria

Purpose: The rapid expansion of urban areas worldwide is widely attributed to the growth of urban populations. The objective of this study is to examine the expansion of urban sprawl in the North Central area of Nigeria, specifically along the Abuja-Keffi highway corridor, over a period of 29 years, from 1991 to 2020. Methodology: The study utilised satellite imagery from three distinct spatio-temporal intervals (1991–2003, 2003–2015, and 2015–2020) and incorporated three different types of Landsat sensors, namely Enhanced Thematic Mapper (ETM), Enhanced Thematic Mapper Plus (ETM+), and Operational Land Imager (OLI). The study employed image processing and land use classification analysis techniques to generate land use and land cover (LULC). Results: The analysis of the data reveals that there has been a significant increase in sprawling development along the Abuja-Keffi highway corridor. The built-up area of the region has undergone significant expansion over the past three decades, with the urbanised land area increasing from 1081.98 hectares (4.96%) in 1991 to 10263.15 hectares in 2020, accounting for 47.06% of the total built-up area. The research also documented two distinct forms of urban growth, specifically linear and leapfrog, throughout the corridor. Applications/Originality/Value: The research recommends regional urban policy, urban growth boundaries as well as effective and efficient development control mechanism in the selected settlements along the corridor. The Abuja Municipal Area Council and Karu Local Government are urged to promote urban renewal and infrastructure development through private partnership, sustainable policies, waste management systems and community engagement.

A Floristic Study of Aquatic and Wetland Plants of Lal Nalla Dam of Samadrapur Tehsil, District Wardha, Maharashtra

The floristic diversity studywas carried out at Lal Nalla Dam. It was constructed on the Lal Nalla River, the nearest city to the dam is Samudrapur in Wardha District of Maharashtra. Extensive and repeated field surveys were carried out from January 2020 to December 2021 in the study area, covering all the seasons of the year to document the species richness of the wetland. The three sites were selected from where a comprehensive list of aquatic and wetland plants occurring in the study areais prepared. During field surveys, emphasis was given to document the type of vegetation, growth form, and associated species. Morphological characters were recorded based on fresh material in the field. The open water zone of the lake has less growth of submerged and free-floating plants. The Marginal shallow zone with a depth of 30-40 cm is inhibited by the floating-leaved-like and emergent plants. In the study area total of 41 species were investigated from three major habitats as open-water zone, marginal shallow zone, and seasonal puddles were studied and according to the sites, the growth formlike one floating-leaved,five submerged plants, twenty-nine emergent, and six other plants was identified belonging to 22 different families in which Cyperaceae was a dominant family with 6 species. The study area shows species diversity but because of seasonal water level change and grazing by domestic livestock the disturbance is seen in vegetation.

Adversity and Resiliency: Athlete Experiences within U.S. College Sport

Research regarding the benefits and detriments of the U.S. collegiate sport governance structure are mixed. Guided by Richardson’s Resiliency Theory (2002), former athletes (n = 215) revealed specific themes of adversity experienced during college with the most prevalent including injury, time demands, and coach-athlete tension. Through interview, athletes noted adversity promoted their resiliency, facilitated grit/perseverance, enhanced teamwork and time management skills, and led to other forms of growth. This study extends our understanding of the long-term impacts of competitive sport participation in this context. This understanding is important for administrators seeking to maximize participant experiences and emulate, enhance, or reform the U.S. College Sport governance model.

Involvement of Academic Staff in the Practice of Professional Development

The article explores the level of involvement of scientific and pedagogical professionals in various social activities for professional development compared to other employee groups. It argues that obtaining additional professional training can be a valuable tool for career growth. The author sees professional development as an integral part of academic growth for scientific and educational workers, along with personal and career development. The findings are based on a combination of theoretical and empirical research conducted by domestic and international scholars, as well as official statistical data and the results of an original sociological study. The study involved a questionnaire survey of scientific and educational professionals (n = 223), as well as other employee groups (n = 833), in the Tyumen and Sverdlovsk regions. As a result, it was found that scientific and pedagogical workers are more likely to engage in professional development activities compared to other categories of the employed population. Continuing professional education programs appear to be the most common form of professional growth. Due to their specialized activities, academic staff tend to develop digital skills more often, while other groups develop personal skills to a greater degree. Based on the level of involvement in professional development, we identified five groups of respondents: “active and engaged”, “achieving the desired level or feeling disappointed”, “questioning or confused”, “recognizing the importance of professional development”, and “rejecting professional development”. The theoretical and empirical findings led to the development of potential strategies to enhance the engagement of scientific and educational professionals in ongoing skill development and acquisition of new competencies. This article is aimed at university management responsible for professional development of academic staff. The findings presented here may have practical implications for the development of personnel strategies at universities with the goal of increasing human capital and professional competence among academic staff, as well as motivating them to engage in continuous learning. The results of this study could be beneficial for participants in the academic community, as well as for specialists involved in developing educational programs and planning the future of universities strategically. The material presented in this paper is relevant not only for academic staff, but also for graduate students who are focused on their continuous professional growth within the academic sector.

New insights into a sensitive life stage: hydraulics of tree seedlings in their first growing season.

The first year in a tree's life is characterized by distinct morphological changes, requiring constant adjustments of the hydraulic system. Despite their importance for the natural regeneration of forests and future vegetation composition, little has been known about the hydraulics of tree seedlings. At different times across the first growing season, we analysed xylem area-specific (Kshoot_Axyl) and leaf area-specific (Kshoot_L) shoot hydraulic conductance, as well as embolism resistance of three temperate conifer trees, two angiosperm trees and one angiosperm shrub, and related findings to cell osmotic parameters and xylem anatomical traits. Over the first 10 wk after germination, Kshoot_Axyl and Kshoot_L sharply decreased, then remained stable until the end of the growing season. Embolism resistance was remarkably low in the youngest stages but, coupled with an increase in cell wall reinforcement, significantly increased towards autumn. Contemporaneously, water potential at turgor loss and osmotic potential at saturation decreased. Independent of lineage, species and growth form, the transition from primary to secondary xylem resulted in a less efficient but increasingly more embolism-resistant hydraulic system, enabling stable water supply under increasing risk for low water potentials.

Relating ten years of rock temperature monitoring to rockwall weathering processes in steep mountain valleys in western Norway

Most existing studies on rockwall frost regimes and frost weathering at rockwalls focus on permafrost-affected rockwalls. However, a high share of rockwall surface areas in Norway and in many other cold-climate environments is actually free of permafrost. It is therefore of interest how these permafrost-free rockwall systems will respond to future changes in air and rock temperatures. In this study, we report field measurements conducted at rockwalls beneath the current permafrost limit and investigate thermal regimes at rockwalls that include both rockwall areas with and without permafrost. We present a unique dataset of up to ten years of rockwall temperature measurements from ten temperatures sensors installed in two mountain valleys in western Norway. An analysis of the different rockwall thermal regimes with respect to rock weathering and associated rockfall supply for both, permafrost-affected and permafrost-free rockwalls is provided. The highest intensity of recent rockwall weathering including determined rockwall retreat rates and associated rockfall supply is detected for northeast-facing rockwalls followed by south-facing rockwalls in our study area. Frost cracking activity, probably in the form of segregation ice growth, seems to be an important factor particularly for the high weathering intensity on northeast-facing rockwalls whereas solar radiation-induced thermal stresses, which favour incremental subcritical crack growth, is assumed to play a relevant role in the moderate weathering intensity on south- and southwest-facing rockwalls. A mean annual and study area-wide rockwall retreat rate of 0.24 mm yr−1 is estimated for our ten-year investigation period (2010−2020) which is comparable to other published rates in similar lithologies and climates. As it can be assumed that seasonal frost regimes and permafrost will react differently to ongoing and future climate changes, more attention should be paid to analyse these two different thermal regimes with respect to possible varied implications for mechanical rockwall weathering and associated rockfall supply.

Botanical origins of honeys from pollen analysis during the main honey flow across agro-ecologies in kelala district, South Wollo, Ethiopia

This study aimed to identify the botanical origins of honey through pollen analysis across agro-ecologies of Kelala district, South Wollo, Ethiopia. Fifteen honey samples were collected from traditional beehives, with 5 samples from each of the highland, midland, and lowland agro-ecologies. Qualitative and quantitative pollen analyses revealed that 22 honeybee plants belonging to 8 families, with no families of poisonous origin, and 3 growth forms were identified. Among these plant species, 18 were found in the midland and 13 were recorded in each of the highland and lowland agro-ecologies. The family Fabaceae, with 7 (31.81 %) of the identified honeybee plants, was highly dominant (p < 0.03) compared to the other families. Herbs, with 18 plant species, were highly dominant (p < 0.001) compared to shrubs and trees. In terms of plant species diversity, 10 plant species (Bidens pachyloma, Guizotia scabra, Becium grandiflorum, Eleusine floccifolia, Lens culinaris, Lippia adoensis, Medicago polymorpha, Ocimum basilicum, Trifolium steudneri, and Zea mays) were found in more than 50 % of the honey samples, with the first 2 in all the samples studied. Analysis of each honey sample showed that 8 (53.33 %) of the samples were monofloral, 3 (20 %) were bifloral, and the rest were multifloral. However, all the honeys produced due to agro-ecology (geographical origin) were monofloral. Guizotia scabra in the highland and Bidens pachyloma in the midland and lowland agro-ecologies were the predominant pollen producing species and contributors of monofloral honey. In conclusion, the safe and healthy monofloral honey produced across agro-ecologies suggests the suitability of the honey for human consumption and can potentially attract investors.

Comparative efficacy of essential oils against Cutibacterium acnes: effect upon strains from phylotypes with different virulence patterns

ObjectivesDespite being a commensal of human skin, Cutibacterium acnes plays an important role in the pathogenesis of Acne vulgaris, with the loss of bacterial phylotype diversity being related to disease progression. This study evaluated differences in the virulence profile of C. acnes strains from different phylotypes and investigated the possible phylotype-selective efficacy of essential oils (EOs) from Thymus x citriodorus (TC), Thymus mastichina, and Cistus ladanifer compared to Melaleuca alternifolia, focusing on both planktonic and biofilm growth forms, the latter being related with pathogenesis and treatment resistance. MethodsOne collection strain and seven clinical isolates were classified into phylotypes using multiplex-touchdown PCR. Virulence trait differences across phylotypes were evaluated by studying antibiotic resistance, biofilm formation, porphyrin production, and lipase activity. EOs were tested for minimum inhibitory/bactericidal concentrations (MIC/MBC) and effects on biofilm biomass and metabolic activity. ResultsStrains from phylotype IA1 were higher biofilm and lipase producers than phylotype II strains. Regarding EO’s efficacy, TC EO presented lower planktonic MIC values for all strains compared to the other EOs, presenting a smaller difference in MIC values across phylotypes. TC EO was able to similarly reduce biofilm biomass and metabolic activity in phylotype IA1 clinical strains, being effective at lower concentrations compared with the remaining EOs. ConclusionsNot all virulence traits were phylotype-related, highlighting the multifactorial nature of the disease. TC EO showed a relevant anti-acne potential, outperforming tea tree EO (a species with a commercial claim for Acne vulgaris) against both planktonic and biofilm forms of C. acnes.