6,204 research outputs found

    Revisão taxonómica do género Calendula L. (Asteraceae - Calenduleae) na Península Ibérica e Marrocos

    Get PDF
    The genus Calendula L. (Asteraceae - Calenduleae) includes, depending on the author, 10 to 25 species, distributed mainly in the Mediterranean basin. The taxonomy of this genus is considered to be extremely difficult, due to a great morphological variability, doubtfull relevance of some of the characters used to distinguish its species (e.g. the life form: annual or perennial; the habit: erect or diffuse, shape of the leaves, indumentum, relative size of the capitula and colour of disc or ray florets, achene morphology), but also due to the hybridization and polyploidization. Despite the numerous studies that have been published, no agreement on the classification and characters used to discriminate between taxa has been reached. A taxonomic study of the genus Calendula was conducted for the Iberian Peninsula and Morocco, aiming at (1) access the morphological variability between and within taxa, (2) confirm the chromosome numbers, (3) increase the nuclear DNA content estimations, (4) re-evaluate taxa delimitations and circumscription, and (5) reassess, and redefine, the descriptions and characters useful to distinguish taxa. In order to achieve a satisfying taxonomic core, extensive fieldwork, detailed morphometric analysis, chorological, karyological and genome size studies were conducted. For the Iberian Peninsula, four species were recognized, including nine subspecies (between these two new subspecies were described). For Morocco, including some taxa from Algeria and Tunisia 13 species were recognized (two new species and a nomenclatural change), including 15 subspecies (among these eight new subspecies were described). To corroborate the results obtained and to evaluate the evolutionary relationships among taxa, phylogenetic studies using molecular methods, such as ITS, microsatellites or other molecular markers, should be used.O g√©nero Calendula L. (Asteraceae - Calenduleae) inclui, dependendo do autor, 10 a 25 esp√©cies, distribu√≠das essencialmente na bacia do Mediterr√Ęneo. A taxonomia deste g√©nero √© considerada extremamente dif√≠cil, devido √† grande variabilidade morfol√≥gica, discutivel relev√Ęncia de alguns dos caracteres utilizados para distinguir suas esp√©cies (por exemplo, a forma de vida: anual ou perene, o h√°bito: erecto ou difuso, a forma das folhas, o indumento, o tamanho e a cor dos cap√≠tulos e a morfologia dos aqu√©nios), mas tamb√©m devido √† hibridiza√ß√£o e poliploidiza√ß√£o. Apesar dos in√ļmeros estudos que foram publicados, n√£o foi alcan√ßado um acordo sobre a classifica√ß√£o e os caracteres utilizados para discriminar as suas esp√©cies. Um estudo taxon√≥mico do g√©nero Calendula foi realizado para a Pen√≠nsula Ib√©rica e Marrocos, com o objectivo de (1) verificar a variabilidade morfol√≥gica, (2) confirmar o n√ļmero de cromossomas, (3) aumentar as estimativas de conte√ļdo em ADN, (4) reavaliar a delimita√ß√£o e a circunscri√ß√£o dos taxa, e (5) reavaliar e redefinir as descri√ß√Ķes e caracteres √ļteis para os distinguir. Para alcan√ßar uma robust√™s taxon√≥mica satisfat√≥ria, foram realizados extensos trabalhos de campo, an√°lise morfom√©trica detalhada, abordagens corol√≥gicas, cariol√≥gicas e quanto ao conte√ļdo em ADN. Para a Pen√≠nsula Ib√©rica, quatro esp√©cies foram reconhecidas, incluindo nove subesp√©cies (entre essas duas novas subesp√©cies foram descritas). Para Marrocos, incluindo alguns taxa da Argelia e Tunisia, foram reconhecidas 13 esp√©cies (duas novas e uma mudan√ßa nomenclatural), incluindo 15 subesp√©cies (entre essas oito novas subesp√©cies foram descritas). Para corroborar os resultados obtidos e avaliar as rela√ß√Ķes evolutivas e filogen√©ticas entre os taxa, estudos que utilizem diferentes m√©todos moleculares, tais como ITS, microsat√©lites ou outros marcadores moleculares, devem ser utilizados.Apoio financeiro do Laborat√≥rio Associado CESAM - Centro de Estudos do Ambiente e do Mar (AMB/50017) financiado por fundos nacionais atrav√©s da FCT/MCTES e cofinanciado pelo FEDER (POCI-01-0145-FEDER-007638), no √Ęmbito do Acordo de Parceria PT2020, e Compete 2020Programa Doutoral em Biologi

    The Impacts of Clearcutting on Understory Plants and Culturally Significant Species In Coastal Western Hemlock Forests of Vancouver Island

    Get PDF
    The goal of the study is to understand successional changes in an understory plant community after clear-cut timber harvesting. The forest ecosystem is within the Southern Very Wet Hypermaritime biogeoclimatic subzone in the broader Coastal Western Hemlock zone along the west coast of Vancouver Island. The ecosystem is located in Huu-ay-aht First Nations traditional territory, and the subzone falls within various Nuu-chah-nulth First Nations traditional territories. A chronosequence was used to categorize various stages of forest growth in five successional stages: Regeneration, Immature, Thinning, Mature, and Old-growth. Forests censused ranged in age from 1 to 354 years old with old-growth stages described as stands over 250 years. The leaf cover and stem density of understory plant species were recorded within 83 subplots. These metrics were evaluated with regard to environmental variables (slope aspect, elevation, canopy openness, soil pH, A horizon depth, soil profile depth, tree basal area, tree stem density, ground moss cover, and bare ground cover) to determine which, if any, factors influenced understory species composition and structure. Out of 45 species identified, 19 are culturally significant plant species to the Nuu-chah-nulth First Nations. The species restricted to one successional stage were identified, with emphasis on opportunistic species in early stages and rare species in the Old-growth stage. There was a large decrease in many culturally significant species immediately after clearcutting. There was a large decrease in species (stem density, leaf cover, species richness, species diversity) from the Regeneration stage to the Thinning stage (1 to 80 years); however, these values steadily increased thereafter. Plant leaf cover and stem density were influenced by the amount of light reaching the understory. The natural disturbance regime that shade-tolerant plants are adapted to in these old-growth forests is small-scale gap formations, which clearcutting does not mimic. Timber harvesting options are recommended to better mimic the natural disturbance regime in this region, which is optimal for the understory species in this region. Many rare and culturally significant plant species were negatively impacted by clearcutting. Protecting rare plant species in old-growth forests is important for maintaining forest biodiversity and indigenous cultural practices in the future

    European scenarios for future biological invasions

    Get PDF
    1. Invasive alien species are one of the major threats to global biodiversity, ecosystem integrity, nature's contributions to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in the future across spatial scales. 2. Based on previous work on global invasion scenarios, we developed a workflow to downscale global scenarios to a regional and policy-relevant context. We applied this workflow at the European scale to create four European scenarios of biological invasions until 2050 that consider different environmental, socio-economic and socio-cultural trajectories, namely the European Alien Species Narratives (Eur-ASNs). 3. We compared the Eur-ASNs with their previously published global counterparts (Global-ASNs), assessing changes in 26 scenario variables. This assessment showed a high consistency between global and European scenarios in the logic and assumptions of the scenario variables. However, several discrepancies in scenario variable trends were detected that could be attributed to scale differences. This suggests that the workflow is able to capture scale-dependent differences across scenarios. 4. We also compared the Global- and Eur-ASNs with the widely used Global and European Shared Socioeconomic Pathways (SSPs), a set of scenarios developed in the context of climate change to capture different future socio-economic trends. Our comparison showed considerable divergences in the scenario space occupied by the different scenarios, with overall larger differences between the ASNs and SSPs than across scales (global vs. European) within the scenario initiatives. 5. Given the differences between the ASNs and SSPs, it seems that the SSPs do not adequately capture the scenario space relevant to understanding the complex future of biological invasions. This underlines the importance of developing independent but complementary scenarios focussed on biological invasions. The downscaling workflow we implemented and presented here provides a tool to develop such scenarios across different regions and contexts. This is a major step towards an improved understanding of all major drivers of global change, including biological invasions

    Systematic conservation planning for Antarctic research stations

    Get PDF
    The small ice-free areas of Antarctica are essential locations for both biodiversity and scientific research but are subject to considerable and expanding human impacts, resulting primarily from station-based research and support activities, and local tourism. Awareness by operators of the need to conserve natural values in and around station and visitor site footprints exists, but the cumulative nature of impacts often results in reactive rather than proactive management. With human activity spread across many isolated pockets of ice-free ground, the pathway to the greatest reduction of human impacts within this natural reserve is through better management of these areas, which are impacted the most. Using a case study of Australia's Casey Station, we found significant natural values persist within the immediate proximity (<10 m) of long-term station infrastructure, but encroachment by physical disturbance results in ongoing pressures. Active planning to better conserve such values would provide a direct opportunity to enhance protection of Antarctica's environment. Here we introduce an approach to systematic conservation planning, tailored to Antarctic research stations, to help managers improve the conservation of values surrounding their activity locations. Use of this approach provides a potential mechanism to balance the need for scientific access to the continent with international obligations to protect its environment. It may also facilitate the development of subordinate conservation tools, including management plans and natural capital accounting. By proactively minimising and containing their station footprints, national programs can also independently demonstrate their commitment to protecting Antarctica's environment

    Effects of Hemiparasites in Grassland Restorations Are Not Universal

    Get PDF
    Root hemiparasites infiltrate the vascular tissue of host roots to acquire water and nutrients, which often reduces host growth. Hemiparasites are postulated to be keystone species in grassland communities if they suppress dominant species and increase plant community biodiversity, and ecosystem engineers if they increase nutrient accessibility for surrounding species. We examined keystone effects by evaluating species richness and evenness in 1 m2 plots in a recent prairie restoration where Castilleja sessiliflora was naturally present or absent, and in a longer-established prairie restoration with or without Pedicularis canadensis. We examined ecosystem engineer effects by determining nitrate and phosphate concentrations under, 25 cm from, and 50 cm from hemiparasites, and in the center of hemiparasite-free plots. On the C. sessiliflora site, plots with the hemiparasites had higher species richness due to more forbs and higher floristic quality, consistent with the keystone species hypothesis. Soil phosphate levels were also greater in plots with C. sessiliflora present, consistent with the hypothesis of ecosystem engineering by this hemiparasite. In contrast, plots with/without P. canadensis showed no associations of any community metrics with the hemiparasite, and no correspondence between the presence of hemiparasites and soil nutrients. Although hemiparasites can increase grassland community heterogeneity, the effect is not universal, and the direction and strength of effects likely depends on local conditions

    Exploring biodiversity and ethnobotanical significance of Solanum species in Uzbekistan: unveiling the cultural wealth and ethnopharmacological uses

    Get PDF
    Despite its millennial existence and empirical documentation, the ethnological knowledge of herbs is a more recent phenomenon. The knowledge of their historical uses as food, medicine, source of income and small-scale businesses, and the sociological impacts are threatened due to the slow ethnobotanical research drive. Species of the genus Solanum have long been extensively used in folk medicine to treat various illnesses of humans since the dawn of civilization. All data were systematically obtained from papers, monographs, and books written in Uzbek, Russian, and English through various scientific online databases, including Google, Google Scholar, PubMed, Scopus, Semantic Scholar, Science Direct, and Web of Science using specific keywords focused on eight Solanum species. Eight native and non-native Solanum species as S. dulcamara L., S. lycopersicum L., S. melongena L., S. nigrum L., S. rostratum Dunal., S. sisymbriifolium Lam., S. tuberosum L., and S. villosum Mill. have been recorded in Uzbekistan of Central Asia. In this article we presented recently obtained data on the diversity, morphological characteristics, global distribution, habitat, population status, phenology, reproduction, pharmacology and phytochemistry of these Solanum species in Uzbekistan. Furthermore, relying on a combination of literature reviews and analyses from various scientific papers, we focus on food consumption coupled with global ethnobotanical and ethnopharmacological uses in human diseases of the Solanum species growing in Uzbekistan. Since the dawn of civilization, these eight cultivated and non-cultivated species of Solanum have provided sustainable resources of medicinal plants in Uzbekistan to prevent and treat various human diseases. Based on the collected data, it was shown that Solanum species have not been studied ethnobotanically and ethnomedicinally in Uzbekistan and it is necessary to conduct phytochemical and biotechnological research on them in the future. Traditional uses and scientific evaluation of Solanum indicate that S. nigrum, S. sisymbriifolium and S. tuberosum are one of the most widely used species in some parts of the world. Although considerable progress has been made to comprehend the chemical and biological properties of S. nigrum and S. tuberosum species, more research on the pharmacology and toxicology of these species is needed to ensure the safety, efficacy, and quality of their biologically active extracts and isolated bioactive compounds. Additionally, conducting additional research on the structure-activity relationship of certain isolated phytochemicals has the potential to enhance their biological efficacy and advance the scientific utilization of traditional applications of Solanum taxa

    Practical methods for the control of tor-grass (Brachypodium pinnatum s.l.) and the restoration of calcareous grassland

    Get PDF
    Calcareous grasslands are sites of high conservation value across Western Europe; however, they are increasingly threatened by the dominance of a native competitive grass, Brachypodium pinnatum, which reduces the diversity of the grassland. Despite this, there is no clear consensus on the most effective method for controlling B. pinnatum and restoring the grassland community. We established two experiments at a calcareous grassland of high nature conservation value in the UK, i) a herbicide spraying experiment with seeding and ii) a seasonal cut-and-graze experiment, to investigate the potential for reducing dense B. pinnatum cover and preventing further expansion of sparse cover, respectively. We examined the effect of different herbicide and cut-and-graze treatments on B. pinnatum cover, and on the species richness and diversity of the grassland over three consecutive years. Herbicide spraying reduced the cover of B. pinnatum, though two spray applications led to a greater reduction longer-term. Species richness and diversity initially declined with the herbicide spray, however this recovered rapidly to levels higher than before spraying commenced. Seeding the spray plots was beneficial for the establishment of Bromopsis erecta and potentially reduced the likelihood of re-colonisation by B. pinnatum and undesirable arable species. The cut-and-graze experiment also showed promising potential in terms of controlling the spread of B. pinnatum. Compared with a single cut in the spring or autumn, cutting and grazing twice, in both spring and autumn was found to reduce the cover of B. pinnatum, whilst also increasing species richness and diversity. Further monitoring is needed to determine the long-term effectiveness of this management treatment

    Connecting competitor, stress-tolerator and ruderal (CSR) theory and Lund Potsdam Jena managed Land 5 (LPJmL 5) to assess the role of environmental conditions, management and functional diversity for grassland ecosystem functions

    Get PDF
    Forage offtake, leaf biomass and soil organic carbon storage are important ecosystem services of permanent grasslands, which are determined by climatic conditions, management and functional diversity. However, functional diversity is not independent of climate and management, and it is important to understand the role of functional diversity and these dependencies for ecosystem services of permanent grasslands, since functional diversity may play a key role in mediating impacts of changing conditions. Large-scale ecosystem models are used to assess ecosystem functions within a consistent framework for multiple climate and management scenarios. However, large-scale models of permanent grasslands rarely consider functional diversity. We implemented a representation of functional diversity based on the competitor, stress-tolerator and ruderal (CSR) theory and the global spectrum of plant form and function into the Lund Potsdam Jena managed Land (LPJmL) dynamic global vegetation model (DGVM) forming LPJmL-CSR. Using a Bayesian calibration method, we parameterised new plant functional types (PFTs) and used these to assess forage offtake, leaf biomass, soil organic carbon storage and community composition of three permanent grassland sites. These are a temperate grassland and a hot and a cold steppe for which we simulated several management scenarios with different defoliation intensities and resource limitations. LPJmL-CSR captured the grassland dynamics well under observed conditions and showed improved results for forage offtake, leaf biomass and/or soil organic carbon (SOC) compared to the original LPJmL 5 version at the three grassland sites. Furthermore, LPJmL-CSR was able to reproduce the trade-offs associated with the global spectrum of plant form and function, and similar strategies emerged independent of the site-specific conditions (e.g. the C and R PFTs were more resource exploitative than the S PFT). Under different resource limitations, we observed a shift in the community composition. At the hot steppe, for example, irrigation led to a more balanced community composition with similar C, S and R PFT shares of aboveground biomass. Our results show that LPJmL-CSR allows for explicit analysis of the adaptation of grassland vegetation to changing conditions while explicitly considering functional diversity. The implemented mechanisms and trade-offs are universally applicable, paving the way for large-scale application. Applying LPJmL-CSR for different climate change and functional diversity scenarios may generate a range of future grassland productivities.</p

    The effect of grazing and reclamation on rodent community stability in the Alxa desert

    Get PDF
    Ecosystem stability has been of increasing interest in the past several decades as it helps predict the consequences of anthropogenic disturbances on ecosystems. A wild rodent community under reclamation and different grazing disturbances in the Alxa Desert was investigated using live trapping from 2006 to 2011. We studied the rodent community composition, community diversity, and variability of different life history strategies. These results showed that reclamation reduced rodent community stability by increasing temporal variability of community, reducing rodent community resistance as shown by decreasing dominance of KSS strategists, and increased the resistance variability of the rodent community by increasing the variability of abundance and richness for KSS strategists. Grazing reduced rodent community resilience by reducing the dominance of rRF strategists, and increased the resilience variability of the rodent community by increasing the variability of abundance and richness for rRF strategists. Those results may answer the three ecological questions about how ecosystems respond to disturbances from a diversity perspective. The ecosystems with intermediate disturbance are more stable, in other words, with higher resistance and resilience. The increase of KSS strategists means the increase of resistance of the community. The increase of rRF strategists means the increase of community resilience

    Re-evaluating the sensitivity of habitats to climate change

    Get PDF
    This report presents the results of an expert led assessment that refines our understanding of the sensitivity of habitats to climate change. Using the Delphi technique and a panel of academic and practitioner experts, an externally validated 5-point scale of sensitivity was developed for habitats in good and degraded condition. The assessment will guide the prioritisation of interventions to those habitats most sensitive to climate change and thus support efforts to reduce climate risk and support nature recovery
    • ‚Ķ
    corecore