Higher Plant Species Research Articles

Nutritional position of managed honey bees during pollination of native plants by the melissopalynology method

Pollination services are crucial for maintaining ecological stability and ensuring food security for humans. Managed honey bees, which are economically valuable and are experiencing population growth due to the increasing demand for their products, play a significant role in pollination. To produce high-quality honey, beekeepers often choose natural high meadows, characterized by high plant species richness, for their apiaries. This practice, in turn, may contribute to the pollination of native plants, as managed honey bees are likely to forage on diverse floral resources within these meadows In this study, we investigated the nutritional position of managed bees in the pollination of native plants in Iran using the melissopalynology method to determine the extent of their contribution to the pollination of native plants. Ninety-four honey samples were collected from beekeepers located in the natural pastures of two biodiversity hotspots in Iran (Zagros and Alborz). Then, plant pollens were extracted from the honey and photographed by scanning electron microscopy. In the next step, plant species were identified, and their abundance was calculated. The results showed that managed bees visited 54 plant genera, seven of which were non-native plants. Additionally, more plant species and the highest abundance of pollen were observed at altitudes ranging from 1000 to 3000 m. Therefore, beekeepers set up their hives in this altitude range to obtain high-quality honey. In general, in this study, the results of melissopalynological analysis, involving the identification of plant genera and pollen counts, revealed that managed honey bees likely contributed less than 3% to the pollination of native plant species in Iran.

Genome-Wide Analysis of GATA Transcription Factor Family in Quinoa (Chenopodium quinoa): Identification, Characterization, and Expression Profiles

GATA-binding factor (GATA) proteins are the transcription factor (TF) family that are commonly involved in plant growth and development. The GATA TF family has been successfully identified and characterized for various higher plant species, but there is little research on the GATA TF family in quinoa (Chenopodium quinoa). In this present study, a total of 32 CqGATA genes were identified and analyzed in the quinoa genome. While the general features of the CqGATA TFs in quinoa were slightly variable, the majority of genes encoding the CqGATA TFs contained two and three exons. Our phylogenetic analysis demonstrated that the CqGATA TFs could be classified into four different groups. Gene expression analysis indicated that the expression profiles of the CqGATA genes varied in different tissues. Overall, our study could provide a reference for further functional characterization of the CqGATA genes in quinoa.

Transcriptomics and metabolomics analyses provide insights into resistance genes of tree ferns.

As ancient organisms, tree ferns play a crucial role as an evolutionary bridge between lower and higher plant species, providing various utilitarian benefits. However, they face challenges such as overexploitation, climate change, adverse environmental conditions, and insect pests, resulting in conservation concerns. In this study, we provide an overview of metabolic and transcriptomic resources of leaves in two typical tree ferns, A. spinulosa and A. metteniana, and explore the resistance genes for the first time. The landscape of metabolome showed that the compound skimmin may hold medicinal significance. A total of 111 differentially accumulated metabolites (DAMs) were detected, with pathway enrichment analysis highlighting 14 significantly enriched pathways, including 2-oxocarboxylic acid metabolism possibly associated with environmental adaptations. A total of 14,639 differentially expressed genes (DEGs) were found, among which 606 were resistance (R) genes. We identified BAM1 as a significantly differentially expressed R gene, which is one of the core genes within the R gene interaction network. Both the maximum-likelihood phylogenetic tree and the PPI network revealed a close relationship between BAM1, FLS2, and TMK. Moreover, BAM1 showed a significant positive correlation with neochlorogenic acid and kaempferol-7-O-glucoside. These metabolites, known for their antioxidant and anti-inflammatory properties, likely play a crucial role in the defense response of tree ferns. This research provides valuable insights into the metabolic and transcriptomic differences between A. spinulosa and A. metteniana, enhancing our understanding of resistance genes in tree ferns.

Element composition of several marine macrophytes (Crimea, Black Sea) and correlations with the element abundances in sediments and seawater

The study of the element accumulation in marine plants against the backdrop of permanently increasing environmental pollution is of particular importance due to the participation of these plants in biogeochemical cycles. The element abundances are highly variable and depend on both the macrophyte species and environment. The purpose of this study was to analyze the elemental composition of widespread marine plants of different taxonomic affiliations collected in the same area of the Black Sea coast. The contents of 74 elements in three species of lower (red, brown, green algae) and one species of higher plants (seagrass) were analyzed using inductively coupled plasma mass spectrometry. High contents of most elements were found in the red alga Ceramium ciliatum and in rhizomes of the seagrass Zostera noltei. In C. ciliatum, high metal bioaccumulation factors were found, which are dependent also on their concentration in the environment. Compared to the higher plant, all the macroalgae accumulated increased amounts of As and I. The seagrass proved to be a good concentrator of Mo and Sb, and relatively high contents of Mn, Co, Ni, Zn, Cd and Ir were registered in its leaves. High contents of Mg, S, Ge, Se and Ta were found in the green alga Ulva rigida, and elevated levels of Al, As, Sr, Zr, Ru, Rh, Pd, Ag, Ba and Re were noted in the brown alga Gongolaria barbata. The enrichment factors for most elements in the sediments were well above 1 with respect to both the local Late Pleistocene sediments and the upper continental crust. The strength of correlations between the element contents in the plants and sediments was found to decrease with the specific surface area growth and appeared to have a lower asymptotic limit of the sediments–seawater correlation strength.

Fast grassland recovery from viable propagules after reintroducing traditional mowing management on a steep slope

Semi-natural grasslands on steep slopes often show high plant species diversity. These grasslands were traditionally maintained through mowing and/or grazing. The traditional management practices help to maintain species diversity, whereas land abandonment reduces diversity by increasing competition from dominant species and reducing seedling recruitment. The reintroduction of management can reverse species diversity declines, but suitable grassland restoration programs are scarce in Japan. To study the effect of short-term abandonment on seedling ecology, we monitored the vegetation of a Susogari grassland that had been abandoned for 3 years; the grassland occupies a steep slope (ca. 50°) on a hillside above paddy fields, and was traditionally mown. We monitored the vegetation before abandonment, in the 3rd year of abandonment, and in the 1st and 2nd years after restoration of mowing management. Emergence and survival of seedlings was monitored for 18 months after reintroduction of management. We monitored 1,183 seedlings of grassland species and non-target annuals in ten 1-m2 plots. After mowing was reintroduced, most grassland species reappeared or increased in the first and second years. Few seedlings of perennial plants and no seedlings of annuals flowered. An exotic species, Solidago altissima, had a lower survival rate (10%) than grassland species (>30%), and all but two grassland species survived over the 18-month period. Although vegetation composition was not fully recovered, our findings suggest that a steep slope acts as a strong filter that inhibits the establishment of non-target species while enhancing persistence of target grassland species.

Genome-wide identification, characterization, and expression analysis of the small auxin-up RNA gene family during zygotic and somatic embryo maturation of the cacao tree (Theobroma cacao)

Small auxin-up RNA (SAUR) proteins were known as a large family that supposedly participated in various biological processes in higher plant species. However, the SAUR family has been still not explored in cacao (Theobroma cacao L.), one of the most important industrial trees. The present work, as an in silico study, revealed comprehensive aspects of the structure, phylogeny, and expression of TcSAUR gene family in cacao. A total of 90 members of the TcSAUR gene family have been identified and annotated in the cacao genome. According to the physic-chemical features analysis, all TcSAUR proteins exhibited slightly similar characteristics. Phylogenetic analysis showed that these TcSAUR proteins could be categorized into seven distinct groups, with 10 sub-groups. Our results suggested that tandemly duplication events, segmental duplication events, and whole genome duplication events might be important in the growth of the TcSAUR gene family in cacao. By re-analyzing the available transcriptome databases, we found that a number of TcSAUR genes were exclusively expressed during the zygotic embryogenesis and somatic embryogenesis. Taken together, our study will be valuable to further functional characterizations of candidate TcSAUR genes for the genetic engineering of cacao.

Patch growth of seashore paspalum (Paspalum vaginatum) treated with inorganic fertilizer and organic biostimulant

Inorganic fertilizers are often used in the United States in golf courses putting green maintenance. We used milled plant biomass on putting greens to test the hypothesis that organic biostimulants used in putting green maintenance can achieve similar results as inorganic fertilizers. Dilapidated putting greens, #4 and #14, with conspicuous patches at the L.E. Ramey Golf Course in Kingsville, TX, were selected for the study. Each green was split in half with one half selected for treatment and the other half maintained as the control and treated with NPK. Milled Medicago sativa L. mixed with milled high auxin-containing plant species in a ratio of 10:1 was used to test the hypothesis. The mixture was applied in the bio-treated section of the two greens while the golf course management continued to apply inorganic fertilizers on the control section of the study greens. Patch count on the greens was conducted once a week utilizing a randomly placed 1 by 1 m quadrant. Also, soil moisture measurement was taken twice a week on the greens to understand soil moisture retention due to the treatments. Patch count indicates that the bio-treated sections grew and filled significantly faster than the sections treated with inorganic fertilizers. Regression analysis of data collected between July 13th and July 27th indicates a strong linear biostimulant/patch growth relationship (R2 = 0.75 and 0.92) on Greens #4 and #14 respectively. Also, soil moisture data indicates significantly higher moisture retention on the putting green sections treated with the biostimulant.

Using faecal nitrogen as a marker to estimate intake and digestibility in sheep fed multi-species native forage

Livestock production in southern South America heavily relies on extensive native grasslands, characterized by high plant species diversity, which makes estimating forage digestibility and intake by ruminants in this pastoral ecosystem challenging. Therefore, the aim of this study was to develop regression models to establish the relationship between total faecal nitrogen excretion (FNe) and organic matter (OM) intake, and faecal nitrogen content (FNc) and OM digestibility in sheep fed multi-species native forage. In a completely randomized design, 16 Corriedale sheep averaging 44 kg of body weight (BW) were housed in metabolism cages and received forage in amounts of 15, 20, 25 g of dry matter per kg of BW or ad libitum. During the spring of 2019 and the summer of 2020, four measurement periods were carried out. The sheep had 5 days of adaptation to the metabolism cage, 10 days to adapt to the treatments of amounts of forage offered, and 5 days for intake and digestibility measurements. The forage was harvested once a day, and then the fresh forage was offered at two different times, 8 and 17 h. A linear regression model was developed to estimate OM intake in sheep fed multi-species native forage based on the FNe [Intake (g OM/sheep/day) = 107.7 + 101.5 × FNe]. An exponential regression model was developed to estimate forage OM digestibility in sheep based on the FNc (Digestibility = 0.31411e0.02995 × FNc). In conclusion, our findings highlight that the OM intake can be precisely estimated using FNe and a reasonably precise estimation of the forage OM digestibility can be reached by assessing FNc in sheep fed a multi-species native forage from the Rio de la Plata region in South America.

Current Status of Potential Antiviral Drugs Derived from Plant, Marine, and Microbial Sources

Abstract: Natural substances have been the principal source of medications since antiquity. Natural goods are gaining popularity as a source of novel medications. This article investigates a variety of variables like plant, marine, and microbial sources that contribute to the growing interest in natural goods as a source of novel medications. Viruses have remained resistant to treatment and prevention for a longer period than other forms of life. Viral diseases can currently only be treated with a limited number of drugs. Significant research initiatives have been committed to identifying novel antiviral natural compounds to fight viruses that harm people, plants, insects, animals, fungi, and microbes. A recent study of the prevalence and sources of antiviral medications licensed by the Food and Drug Administration (FDA) has focused on natural products. Out of the estimated 250,000 higher plant species, only 5 to 15 percent have been thoroughly evaluated for the existence of bioactive substances in them, and the ability of the other species has hardly been investigated. This review aims to offer an overview of the crucial role played by natural products in the discovery and development of novel antiviral drugs with potent antiviral activity, including phytochemicals such as carbohydrates, coumarins, flavonoids, chromones, alkaloids, lignans, phenols, tannins, proteins, peptides, antiviral plant extracts, other marine, and microbial sources.

Comparative Mitogenomics Analysis Revealed Evolutionary Divergence among Neopestalotiopsis Species Complex (Fungi: Xylariales).

The genus Neopestalotiopsis consists of obligate parasites that cause ring spot, scab, and leaf blight diseases in higher plant species. We assembled the three complete mitogenomes for the guava fruit ring spot pathogen, Neopestalotiopsis cubana. The mitogenomes are circular, with sizes of 38,666 bp, 33,846 bp, and 32,593 bp. The comparative analyses with Pestalotiopsis fici showed that N. cubana differs greatly from it in the length of the mitogenomes and the number of introns. Moreover, they showed significant differences in the gene content and tRNAs. The two genera showed little difference in gene skewness and codon preference for core protein-coding genes (PCGs). We compared gene sequencing in the mitogenomes of the order Xylariales and found large-scale gene rearrangement events, such as gene translocations and the duplication of tRNAs. N. cubana shows a unique evolutionary position in the phylum Ascomycota constructed in phylogenetic analyses. We also found a more concentrated distribution of evolutionary pressures on the PCGs of Neopestalotiopsis in the phylum Ascomycota and that they are under little selective pressure compared to other species and are subjected to purifying selection. This study explores the evolutionary dynamics of the mitogenomes of Neopestalotiopsis and provides important support for genetic and taxonomic studies.

Success in restoring native plant communities on kimberlite mining dumps in the Afro-alpine Drakensberg region of Lesotho.

Rehabilitation strategies for degraded mine dumps have generally seen limited success due to different complications associated with mining biophysical disturbance. In this study, we tested a combination of two methods to expedite revegetation of kimberlite tailings at Letseng Diamond Mine (i.e., in the Afro-alpine areas of Lesotho). We ran trials on different growth media located on fine and coarse kimberlite tailings (i.e. sites) mixed with different substrate combinations and topsoil and sowing a seed mix comprised of native plant species. Overall, as predicted, fine kimberlite tailings displayed significantly higher plant abundance than coarse kimberlite tailings, and sown seeds performed significantly better than spontaneous colonisation by emerging species. Kimberlite tailings mixed with topsoil (100 mm) showed significantly greater plant abundance, and similarly, when coarse kimberlite tailings were introduced to fine tailings. Physicochemical analyses of growth media components suggested that topsoil provided additional nutrients and that plants could readily access available nutrients in the fine kimberlite tailings. We noted a gradual significant increase in plant abundance over 5 years, enhanced by new plant species emerging from the topsoil seed bank or by natural seed dispersal. Although plant abundance differed significantly, both fine and coarse kimberlite tailings displayed high plant species diversity (H = 3.4 and D = 0.95 and H = 3.5 and D = 0.95, respectively). Out of 36 emerging plant species, 15 species spontaneously colonised both growth media. The significant variation in abundance among plant species between treatments was mostly attributed to dominant forb species, namely Chrysocoma ciliata, Glumicalyx montanus, Oxalis obliquifolia, Senecio inaequidens and Trifolium burchellianum. We have identified suitable growth media for plant community restoration on kimberlite tailings in the Drakensberg alpine area using a seed mix of native plant species in combination with natural seed dispersal from the surrounding pristine environment. We provide evidence for using two complementary approaches to optimise native plant community development during restoration in the Drakensberg alpine area.

Potentials of palynotaxa for apicultural entrepreneurships: Implication for conservation and policy

The contemporary global economic meltdown has devastating effect on the economy of most rural people in Africa in general and Nigeria in particular. The frantic search for alternative source of national revenue aside from oil and gas has become imperative for economic emancipation of Nigerians. Knowledge of plants foraged by bees for pollen and nectar becomes a panacea to this challenge. This study analysed the pollen spectrum of four honey samples collected from Southern Nigeria in order to determine the richness of the honey plants in the area, and to highlight the potential of these species in apicultural entrepreneurship in Nigeria for green growth economy, using Shannon-Wiener Diversity Index after a standard acetolysis method. A total number of 39 palynotaxa belonging to 21 plant families and distributed in 39 genera were identified. Fabaceae had the highest plant species (11 species), followed by Euphorbiaceae (5 species). The study revealed that Elaeis guineensis Jacq, Anacardium occidentale L. Diospyros mespiliformis Hochist ex ADC, Alchornea cordifolia (Muell)Arg, Daniella oliveri (Rolfe) Hutch & Dalz, Irvingia wombolu Okafor ex Baill, Treculia africana Decne, Nauclea latifolia Smith and Crossopteryx febrifuga Afzil ex Benth, were the dominant honey plants. The palynotaxa spectrum did not vary greatly in the four samples; however, Shannon diversity index was low to moderate (H= 2.7 -3.1). This baseline information has provided opportunity and amazing potentials for apicultural enterprise in these areas. However, most of these honey plants are rare, threatened and endangered. This calls for urgent conservation strategies by all players. Policy programmes could increase production and productivity of hive products through capacity- building for local populace.

The loss of plant functional groups increased arthropod diversity in an alpine meadow on the Tibetan Plateau.

Plant species loss, driven by global changes and human activities, can have cascading effects on other trophic levels, such as arthropods, and alter the multitrophic structure of ecosystems. While the relationship between plant diversity and arthropod communities has been well-documented, few studies have explored the effects of species composition variation or plant functional groups. In this study, we conducted a long-term plant removal experiment to investigate the impact of plant functional group loss (specifically targeting tall grasses and sedges, as well as tall or short forbs) on arthropod diversity and their functional groups. Our findings revealed that the removal of plant functional groups resulted in increased arthropod richness, abundance and the exponential of Shannon entropy, contrary to the commonly observed positive correlation between plant diversity and consumer diversity. Furthermore, the removal of different plant groups had varying impacts on arthropod trophic levels. The removal of forbs had a more pronounced impact on herbivores compared to graminoids, but this impact did not consistently cascade to higher-trophic arthropods. Notably, the removal of short forbs had a more significant impact on predators, as evidenced by the increased richness, abundance, the exponential of Shannon entropy, inverse Simpson index and inverse Berger-Parker index of carnivores and abundance of omnivores, likely attributable to distinct underlying mechanisms. Our results highlight the importance of plant species identity in shaping arthropod communities in alpine grasslands. This study emphasizes the crucial role of high plant species diversity in controlling arthropods in natural grasslands, particularly in the context of plant diversity loss caused by global changes and human activities.

Effect of HKUST-1 metal–organic framework in root and shoot systems, as well as seed germination

The seed germination, as well as root and shoot growth effect of HKUST-1 MOF, and its derived linear polymer ([Cu2(OH)(BTC)(H2O)]n·2nH2O) were herein examined. These effects were studied for seven higher plant species: sweet corn (Zea mays L.), black bean (Phaseolus vulgaris L.), tomato (Solanum lycopersicum L.), lettuce (Lactuca sativa L.), celosia (Celosia argentea L.), Aztec marigold (Tagetes erecta L.), and gypsophila (Gypsophila paniculata L.). The studied concentrations of MOFs were 10, 100, 500, or 1000 mg/L, enhancing the percentage of germination and growth of plants in most species. In general, the growth of the root is lower compared to the controls due to the capacity of the MOF to adsorb water and provide micronutrients such as C, O, and Cu, acting as a reserve for the plant. Shoot system growths are more pronounced with HKUST-1 compared with control, and linear polymer, due to the 3D structure adsorbs major water contents. It was found that all studied species are tolerant not only to Cu released from the material, but more evident to Cu structured in MOFs, and this occurs at high concentrations compared to many other systems. Finally, copper fixation was not present, studied by EDX mapping, banning the possibility of metallic phytotoxicity to the tested cultivars.

Thermal germination characteristics of three High Arctic plants: Implications for their response to climate warming

Although temperature plays a crucial role in governing seed reproduction in High Arctic plants, little is known about the germination response of these plants to climate warming. We conducted a germination experiment to examine the thermal germination characteristics of three common High Arctic plant species in Svalbard: Dryas octopetala, Oxyria digyna, and Salix polaris. We exposed the seeds to two temperature regimes: gradually increasing and decreasing temperatures between 4 and 15 °C. Additionally, we measured the ground surface temperatures at the study site. All three High Arctic plant species exhibited no specific temperature requirements for germination, with minimum germination temperatures falling within the range of 4–8 °C. Based on the ground surface temperature data, the period during which the weekly average ground surface temperature exceeded this minimum germination temperature range (period available for germination) spanned from mid-June to mid-August. By simulating a warming scenario of 2 and 4 °C, we estimated that the onset of the period available for germination would advance by 1–2 and 2–3 weeks, respectively. Furthermore, our results suggest the possibility of autumn germination in the High Arctic region under future warming conditions.

Diversity of Plant Species in Moringa-Based Homestead of Jaintiapur Upazila in Sylhet District

Homestead agroforestry is crucial for food, fiber, and other necessities which are required outside the conventional forests. Thus, homestead agroforestry meets the criteria for a sustainable forest management scheme, providing a better way for biodiversity conservation. Moringa based homestead agroforestry in Sylhet has an opportunity to encourage species diversity for its various structural properties. This paper explores the plant species diversity of Moringa based homestead area at Jaintiapur upazila in Sylhet. Personal interviews were conducted from June 2022 to September 2022 with 40 randomly selected respondents who were involved in Moringa-based homestead agroforestry. Shannon-Wiener Diversity Indices (SWDI) was used to explore the plant species diversity index. In the study area identified plant species were 50.0% fruits, 26.3% vegetables, 15.8% timber and 7.9% medicinal plants. Among all the plant species, the higher diversity was found in fruit species followed by timber species, vegetable species and medicinal species. Most of plant species were found in boundary side of homestead area. Vegetable plant diversity was found high (Hʹ = 0.94-0.72), fruit species was also high (Hʹ = 0.99-0.69), medicinal species was medium to high (Hʹ = 0.62-0.97) and timber plant species was high (Hʹ =0.86-0.94) in different homestead areas. It may be concluded that plant species diversity as observed in Moringa based homestead area could be a good option for biodiversity conservation in Sylhet area of Bangladesh. SAARC J. Agric., 21(2): 119-129 (2023)

Происхождение и история интродукции Camellia sinensis (L.) O. Kuntze в субтропической зоне Краснодарского края

Tea is one of the oldest and most widespread drinks around the globe. For a part of the population, tea is a product of prime necessity and is a part of many peoples traditional cultures around the world. Scientists worldwide have been interested in studying not only the biology and ecology of one particular species of higher plants but also other branches of knowledge that have made it possible to introduce a unique beverage to people all over the world and to involve huge labor resources in its production. There is a wide range of events that have been associated with tea, from medicinal remedies to sporting events. The establishment of tea growing on the territory of the Russian Empire and then in the USSR is a natural world trend and it is inseparably connected with the subtropical zone on the Caucasian Black Sea coast. The change of the social system allowed to organize tea industrial production in the Krasnodar region, having developed special lands and introducing new unique agrotechnical methods. At the moment, there is a decline in the industry due to various factors of economic, political, and legal nature. Plants of Camellia sinensis (L.) O. Kuntze strive to adapt to new conditions and survive among the Colchian forests, despite the upheavals of the nineties of the XX century. All conditions for survival have been created and laid down to the tea plants by man since time immemorial. The aim of this article is to study the origin of tea, the history of the introduction of tea bushes in Krasnodar region, and to highlight the current status of the tea plant. Keywords: CAMELLIA SINENSIS, SUBTROPICS OF RUSSIA, HISTORY OF TEA, INTRODUCTION, KRASNODAR TEA

Medicinal Plants of Ethiopia: Conservation, Traditional Knowledge, and Sustainable Use

Ethiopia, renowned for its remarkable biodiversity, harbors approximately 6,000 species of higher plants, many of which hold significant medicinal value. Traditional medicine plays a crucial role in healthcare, particularly in rural areas where access to modern healthcare is limited. This reliance underscores the importance of preserving indigenous knowledge related to medicinal plants. Home gardens emerge as vital repositories of these valuable plant species, highlighting the need for sustainable conservation strategies. Both in-situ and ex-situ conservation measures, along with home garden cultivation, are essential in safeguarding these invaluable resources. However, the conservation of medicinal plants faces challenges from both natural causes and human-made threats. This paper emphasizes the urgent need for comprehensive conservation efforts that involve collaborative initiatives among local communities, researchers, policymakers, and conservationists. By documenting and preserving indigenous knowledge, we can not only protect the rich biodiversity of Ethiopia but also contribute to the well-being of its people and potential advancements in drug development. This holistic approach ensures the continued availability and sustainable use of medicinal plants, benefiting both the environment and human health.

A new species of Mollinedia (Monimiaceae, Laurales) from the Quadrilátero Ferrífero, Brazil.

Monimiaceae comprises approximately 26 genera and 250 species, with a pantropical distribution, predominantly occurring in humid forests. In Brazil, it is represented by five genera and 47 species, most of which are found in the Atlantic Forest, particularly in dense ombrophilous forest. Nevertheless, studies on this family in other biomes and vegetation types in Brazil are still scarce. The Quadrilátero Ferrífero (QF), a region located in the state of Minas Gerais, exhibits high plant species richness and endemism. During collections and analysis of herbarium materials from this region, some specimens of Mollinedia caught our attention due to a combination of characteristics that do not match those of any described species within the genus. For this reason, we describe this new taxon and assess its risk of extinction. Additionally, we review the occurrences of Monimiaceae in the QF and provide maps of its geographical distribution. With the description of this new species, the region now hosts eight species of Monimiaceae, two from the genus Macropeplus and six from Mollinedia. The new species is the first endemic species of the Monimiaceae family to be described in the QF. Concerning the extinction risk assessment, the new species was assessed as critically endangered.

Vegetation communities and summer net ecosystem CO2 exchange on western Axel Heiberg Island, Canadian High Arctic

Climate change is expected to result in the Arctic transitioning from a carbon sink to a carbon source environment, with models predicting half of the carbon stock of the upper 3 m soil layer to be released by the year 2300 (van Huissteden and Dolman 2012). However, uncertainty in latitudinal warming and changes in Arctic ecosystem functions, such as gross carbon ecosystem exchange (GEE), are poorly understood, in part a reflection of a high variability in vascular plant community diversity that is dependent upon and sensitive to physiographic controls, such as soil moisture, topography, and seasonal active layer depth (Walker et al. 2005). This heterogeneity complicates assessments of carbon fluxes on a landscape scale and how they will change in the future (Shaver et al. 2007), especially given their sensitivity to local changes in climate, such as warming and higher rates of rainfall (Bintanja 2018, Bintanja and Andry 2017). As part of the creation of a long-term ecological and environmental monitoring program at the McGill Arctic Research Station at Expedition Fiord, western Axel Heiberg Island, field-based studies in 2021-2022 of plant surveys and summer net ecosystem CO2 exchange monitoring were undertaken to: define the major vegetation communities; quantify and investigate CO2 fluxes with chambers and their analogous biophysical variables; and upscale plot level CO2 measurements to the landscape scale using high spatial resolution remote sensing data. define the major vegetation communities; quantify and investigate CO2 fluxes with chambers and their analogous biophysical variables; and upscale plot level CO2 measurements to the landscape scale using high spatial resolution remote sensing data. The Expedition Fiord area is recognized as a polar oasis, with high plant species richness existing within an environment of heterogeneous physiography. At the moment, five vegetation communities have been identified (xeric dwarf shrub barren, xeric-mesic dwarf shub barren, mesic dwarf shrub tundra, cassiope heath, and sedge meadow) that varied as a function of species diversity, percent cover, soil moisture, and net ecosystem carbon exchange. Barren vegetation communities having stronger respiration fluxes (i.e., carbon source environments) while more vegetated communities have stronger photosynthesis fluxes (i.e., carbon sink environments). Landcover classification revealed with high accuracy (79.3%) that barren ground and barren vegetation communities cover a much larger area compared to wetter habitats. Upscaling summer season measured carbon fluxes based on the landcover map revealed that Expedition Fiord is a carbon source environment, with an average efflux of +94.6 g CO2/day. Ongoing work focuses on the expansion of carbon flux and subsurface monitoring locations, as well as studies of soil carbon and microbial diversity across the different land cover classifications, which will help to better resolve how soil microorganisms, plant detritus, labile organic carbon, soil moisture, slope, aspect, and bedrock geology influence CO2 fluxes throughout the summer season in this high Arctic setting.