bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollination interactions promoting plant invasions.
Authors: Montero-Castaño Ana , Traveset Anna 
Published: December 2020

Abstract

Most plant species rely on, or benefit from, animal pollination. Therefore, pollination interactions are expected to play a key role in the reproduction and invasion success of non-native plants in their new areas. Understanding this role will allow us to better predict certain plant invasions. Also, it will allow us to explore the potential of invasion management measures based on disrupting or avoiding pollination interactions. In this chapter we review the available information on reproductive systems and their degree of dependence on animal-mediated pollination of non-native plant species. We review the characteristics of resident pollinators feeding on non-native plants and the different environmental setups that allow or impede non-native plants to reproduce in their new areas. Finally, we explore the scarce literature on invasion management measures based on disrupting pollination interactions and discuss their potentiality. Evidence so far shows that animal pollination does not usually act as an effective barrier to invasion. Most introduced plants are able to receive suitable pollination service from resident pollinators, while others are able to minimize their reliance on pollinators through different mechanisms (e.g. selfing or asexual reproduction). The environmental settings where the introduction occurs (for instance, the presence of neighbours with similar or dissimilar flower morphologies), can play an important role on the success or failure of non-native plants overcoming reproductive barriers. Although it seems that most introduced plants do not face pollination barriers, we consider that, for certain species, the disruption or avoidance of pollination interactions as control or prevention measures deserve further exploration.
Ungulates as dispersal vectors of non-native plants.
Authors: Baltzinger Christophe , Shukla Ushma , Msweli Lindelwa S. , Downs Colleen T. 
Published: December 2020

Abstract

Ungulates are present worldwide with 257 recorded species, including livestock. They cover different functional gradients, be it feeding regime, digestive strategy, body size, body mass, fur characteristics or sociality. All these specificities may intervene at different stages of animal-mediated plant dispersal. Ungulates move diaspores from both native and non-native plants, through endo- and epizoochory. Initially introduced by humans, non-native plants bearing specific traits can be carried over long distances and to new environments by ungulates. These vectors can further free local resources necessary for the germination and the subsequent growth of the released diaspores. We first looked at trait-based plant community changes at different timescales in the presence of different native ungulates. We then reviewed the literature on endozoochory, regurgitation and fur-epizoochory assisted by ungulates, focusing on the dispersal of non-native plants. We made an overall assessment of ungulate-mediated non-native plant dispersal by biogeographical zone and dispersal mode, and then provided additional information on plant growth form and taxonomy, vectors and associated modes of dispersal. Results are presented for four main ungulate families: Cervidae, Bovidae, Suidae and Equidae. For each family, we highlight our findings either by ungulate if sufficiently represented (e.g. Odocoileus virginianus, Bison bison, Bos taurus) or by group of species. According to their feeding regime, grazers dispersed solely forbs and graminoids whereas omnivores also dispersed plants from other growth forms (i.e. cactus, vine, shrub and tree). Numerous non-native plants are dispersed by ungulates around the world, but this is probably the visible part of the iceberg, as only 32 ungulates (i.e. 12%) have been studied as vectors so far, suggesting their overall contribution is certainly underrated.
The role of plant-plant facilitation in non-native plant invasions.
Authors: Cavieres Lohengrin A. 
Published: December 2020

Abstract

Biological invasions are one the most important drivers of the current environmental changes generating important biodiversity losses. Although several hypotheses have been proposed to understand the mechanisms underpinning biological invasions, most of them relate to negative interactions among native and invasive species, where the capacity for many invasive species to reduce diversity is often attributed to a greater competitiveness. However, neighbouring species can also show facilitative interactions, where the presence of one species can facilitate another directly by improving environmental conditions or indirectly through negative effects on a third party species. This chapter reviews the scientific literature on plant invasion, seeking examples of where facilitative interactions either among native and non-native plant species or among non-native species were demonstrated. There are several examples of native species that directly facilitate a non-native species, while examples of native species having a negative effect either on a native or a non-native species that compete with a target non-native, generating a net indirect facilitative effect of the native on the target non-native, are less numerous. Direct facilitation among non-native species has been reported as part of the 'invasional meltdown' phenomenon (Chapter 8, this volume). There are cases where non-native species can have a negative effect on a native species that competes with a target non-native, generating a net indirect facilitative effect among the non-natives. Finally, a non-native species can have a direct facilitative effect on native species, which might have important implications in restoration.
How direct and indirect non-native interactions can promote plant invasions, lead to invasional meltdown and inform management decisions.
Authors: Kuebbing Sara E. 
Published: December 2020

Abstract

In 1999, Daniel Simberloff and Betsy Von Holle introduced the term 'invasional meltdown'. The term and the concept have been embraced and critiqued but have taken a firm hold within the invasion biology canon. The original formulation of the concept argued two key points: first, biologists rarely study how non-natives interact with one another. Second, nearly all the conceptual models about the success and impact of invasive species are predicated on the importance of competitive interactions and an implicit assumption that non-natives should interfere with establishment, spread and impact of other non-natives. In response, Simberloff and Von Holle called for more research on invader interactions and proposed an alternative consequence of non-native species interactions - invasional meltdown - where facilitative interactions among non-natives could increase the invasion rate or ecological impacts in invaded systems. This chapter outlines the primary pathways in which direct and indirect interactions among non-natives could lead to invasional meltdown. It provides examples of how different types of interactions among non-natives could lead to net positive effects on the invasion success of non-native plants or the impact of non-native plants on invaded ecosystems. Direct effects are by far the most commonly explored form of non-native- non- native interaction, primarily focusing on plant mutualisms with pollinators, seed dispersers or soil microbial mutualists. There are, however, also examples of non-native plants that benefit from commensal and even herbivorous interactions with other non-natives. Indirect interactions among non-natives are very infrequently studied. Although examples are scarce, non-natives may indirectly benefit other non-native plants through trophic cascades, apparent competition and indirect mutualisms. It remains unclear whether indirect effects are important pathways to invasional meltdown. More work is needed on studying ecosystems that are invaded by multiple non-native species and we need to consider the full range of interactions among non-natives that could either stymie or promote their spread, population growth and impact. Only then can we address how common facilitative interactions are relative to competitive interactions among non-natives or provide robust suggestions on how to manage ecosystems.
Biotic resistance to plant invasions.
Authors: Parker John D. , Devaney John L. , Lemoine Nathan P. 
Published: December 2020

Abstract

Biotic resistance to plant invasions takes many forms: consumption by native herbivores, competition with native plants and infection by native pathogens. But how often does biotic resistance prevent the damaging monocultures that typify the most problematic plant invaders, and how often is biotic resistance overwhelmed by the direct and indirect impacts of human activities? This chapter attempts to answer these questions, drawing on the long history of research into biotic resistance. We first briefly describe the major forms of biotic resistance to exotic plant invasions as an antecedent to other, more detailed chapters on competition, herbivory and pathogens. We then describe a new neutral model where variance in disturbance promotes invasions over the short term, but over longer timescales only propagule pressure drives invasions. These findings are a cautionary tale; pending increases in global trade and travel, particularly to the tropics, may provide the prerequisite disturbance and propagule pressure needed to ultimately stoke further invasions. Finally, we highlight case studies where invasions have been mitigated by restoration of biotic resistance from native herbivores and competitors. These studies provide strong empirical support that conservation of native biodiversity can be a nature-based solution to some invasions, although it remains to be seen if climate change will alter these effects over longer timescales.
Impacts of non-native plants on plant-pollinator interactions.
Authors: Aizen Marcelo A. , Morales Carolina L. 
Published: December 2020

Abstract

There has been growing interest in the consequences of invasive non-native plants for the plant-pollinator mutualism, most likely because of its relevance for the maintenance of terrestrial biodiversity and food production. However, the development of this research field has been thematically uneven and the overall evidence inconclusive. Many studies have focused on how non-native plants interact with native plants via pollinator sharing, which have allowed meta-analytical syntheses, whereas several others have looked at how frequently non-native plants integrate into native plant-pollinator webs and how they affect network structure. However, relatively few studies have addressed the consequences of invasive plants for pollinators. Overall, the research approach in this area has been predominantly phenomenological rather than mechanistic, which has hindered our understanding of apparently contradictory evidence. One key characteristic of invasive non-native plants that seems to mediate negative effects on the pollination mutualism is the high relative abundance that they reach at late stages of invasion. This high dominance is apparently the main trigger of all the disruptive direct and indirect effects that are discussed in this chapter. Finally, we identify several intriguing questions on the ecological and evolutionary consequences of invasive plants for the plant-pollinator mutualism waiting to be answered.
How a network approach has advanced the field of plant invasion ecology.
Authors: Emer Carine , Timóteo Sérgio 
Published: December 2020

Abstract

Every organism on Earth, whether in natural or anthropogenic environments, is connected to a complex web of life, the famous 'entangled bank' coined by Darwin in 1859. Non-native species can integrate into local 'banks' by establishing novel associations with the resident species. In that context, network ecology has been an important tool to study the interactions of non-native species and the effects on recipient communities due to its ability to simultaneously investigate the assembly and disassembly of species interactions as well as their functional roles. Its visually appealing tools and relatively simple metrics gained momentum among scientists and are increasingly applied in different areas of ecology, from the more theoretical grounds to applied research on restoration and conservation. A network approach helps us to understand how plant invasions may or may not form novel species associations, how they change the structure of invaded communities, the outcomes for ecosystem functionality and, ultimately, the implications for the conservation of ecological interactions. Networks have been widely used on pollination studies, especially from temperate zones, unveiling their nested patterns and the mechanisms by which non-native plants integrate into local communities. Yet, very few papers have used network approaches to assess plant invasion effects in other systems such as plant-herbivore, plant-pathogen or seed-dispersal processes. Here we describe how joining network ecology with plant invasion biology started and how it has developed over the last few decades. We show the extent of its contribution, despite contradictory results and biases, to a better understanding of the role of non-native plant species in shaping community structure. Finally, we explore how it can be further improved to answer emerging questions.
How can progress in the understanding of antagonistic interactions be applied to improve biological control of plant invasions?
Authors: Hill Martin P. , Coetzee Julie A. 
Published: December 2020

Abstract

Classical biological control has been used as a management tool for invasive non-native plant species globally for over 200 years. There have been some very successful programmes, most notably on waterweeds, cacti and seed reduction in perennial trees. Seventy per cent of agents released have established in at least one instance, and 66% of the targeted invasive species have showed some level of control. However, some programmes have failed to meet expectations, for example on Lantana camara. The most commonly cited reasons for the failure of establishment or limited efficacy of biological control agents are unsuitable climatic conditions and genotype incompatibility. We propose that antagonistic biotic interactions play a significant role in the outcomes of weed biological control programmes. Induced plant defences (physical and chemical) that can be mounted rapidly by the invasive non-native plants can result in the reduction in agent populations after initial attack. Rapid induction of plant defences have been implicated in the lack of long-term establishment of the agent Falconia intermedia that showed great initial promise against the widespread invasive shrub L. camara. Host range expansion by native natural enemies onto biological control agents have also been shown to reduce population growth of agents. Finally, competition from indigenous plant species aids invasive alien plant population reduction in the presence of herbivory. All three factors have been poorly studied and further work is needed to better explain the outcomes of weed biological control programmes.
Multiple feedbacks due to biotic interactions across trophic levels can lead to persistent novel conditions that hinder restoration.
Authors: Yelenik Stephanie G. , D'Antonio Carla M. , Rehm Evan M. , Caldwell Iain R. 
Published: December 2020

Abstract

Unlike traditional successional theory, Alternate Stable Equilibrium (ASE) theory posits that more than one community state is possible in a single environment, depending on the order that species arrive. ASE theory is often invoked in management situations where initial stressors have been removed, but native-dominated communities are not returning to degraded areas. Fundamental to this theory is the assumption that equilibria are maintained by positive feedbacks between colonizers and their environment. While ASE has been relatively well studied in aquatic ecosystems, more complex terrestrial systems offer multiple challenges, including species interactions across trophic levels that can lead to multiple feedbacks. Here, we discuss ASE theory as it applies to terrestrial, invaded ecosystems, and detail a case study from Hawai'i that exemplifies how species interactions can favour the persistence of invaders, and how an understanding of interactions and feedbacks can be used to guide management. Our system includes intact native-dominated mesic forest and areas cleared for pasture, planted with non-native grasses, and later planted with a monoculture of a native nitrogen-fixing tree in an effort to restore forests. We discuss interactions between birds, understorey fruiting native species, understorey non-native grasses, soils and bryophytes in separate feedback mechanisms, and explain our efforts to identify which of these feedbacks is most important to address in a management context. Finally, we suggest that using models can help overcome some of the challenges that terrestrial ecosystems pose when studying ASE.
Leprosy: current status and clinical management
Authors: Rathod Santoshdev P. , Chaudhary Raju G. , Brar Arwinder 
Published: December 2020

Abstract
Around the world nations have adopted the global leprosy strategy 2016–2020 developed by the world health organization to achieve the objective of a leprosy-free world. Despite the disease having been declared as eliminated from most developed nations and parts of the world, every year more than 2,00,000 new cases of leprosy still continue to occur mainly in south east Asian regions (India, Indonesia, Philippines) and south American region of Brazil. The diagnosis of leprosy has remained more or less the same over the years with recent advances in the form of PCR-based molecular diagnosis and immunological markers. Much of the success of national programs have been due to multi-drug therapy. Recently, anti-microbial resistance surveys have shown the need to monitor for drug resistance in leprosy. The countries where the disease is still endemic need to shift their policy towards active surveillance and case finding in the affected districts. We are in the last year of the Global Leprosy Strategy 2016–2020 by WHO: accelerating towards a Leprosy free world, but eradication of the disease seems a distant possibility as of now.
Electrolytic conductivity at pure water level
Authors: Seitz Steffen , Roziková Matilda , Vičarová Martina , Thirstrup Carsten , DeLeeBeeck Lisa Carol , Dumańska Joanna , Gonzaga Fabiano Barbieri , Cunha Kleiton da Cruz , Hernán Galli Ariel , Stoica Daniela , Wang Hai , Haraldsson Conny , Smirnov Aleksey 
Published: December 2020

Main text
Electrolytic conductivity in aqueous solutions is a common electrochemical measurement technique in industry. Since it is sensitive to the amount content of dissolved ions in a solution, a limiting value for conductivity is a clear and simple quality criterium for the ionic purity of pure water, roughly ranging from 0.055 μS/cm to 150 μS/cm at 25 °C. International regulations are becoming stricter with regards to metrological traceability to guarantee compliance of measurement results with relevant standards. Consequently, the NMIs active in this area have been facing an increasing request for the calibration of respective conductivity sensors and for adequate CRMs over the past years. A first, regional comparison has been conducted in 2013/14 (EURAMET 1271). Since an increasing number of NMIs, also from other regions, seek providing respective services and establishing CMCs, EURAMET, i.e. the Sub-Committee on Electro Analysis of TC-MC, opened a follow-up comparison to other regions in terms of a supplementary CCQM comparison (EURAMET.QM-S12). The comparison has been conducted in terms of a Round Robin scheme. A conductivity sensor has been sent around between ten participants for calibration at four conductivity levels (0.055, 0.5, 5 and 50 μS/cm at 25 °C). Basically, the measured measurement errors of the device have been compared in terms of conductivity. Additionally, the cell constants calculated from the calibration results have been compared. Apart from very few outliers, the comparison has demonstrated good equivalence of the calibration capabilities.
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Massive particles in the Einstein–Lovelock–anti-de Sitter black hole spacetime
Authors: Konoplya R A , Zhidenko A 
Published: December 2020

Abstract
An interpretation to the physics of stable geodesics of massive particles in black hole backgrounds has been recently proposed in the context of the AdS/CFT correspondence. It was argued that the existence of stable orbits indicates that the dual state does not thermalize on a thermal time scale and the bulk excitations can be interpreted as metastable states in the dual field theory. Here we study motion of massive particles in the background of the D-dimensional asymptotically anti-de Sitter (AdS) black holes in the Einstein–Lovelock theory. We show that, unlike the asymptotically flat case, for any kind of higher curvature Lovelock corrections there appear a stable circular orbit at a distance from the black hole. We find the general analytical expressions for the frequencies of distant circular orbits and radial oscillation frequencies. We show that the corresponding correction has the same power as in the Schwarzschild–AdS case, implying a universal scaling with the temperature for any Lovelock theory.
Balloon and chain: an instructive variable mass system
Authors: Denny Mark 
Published: December 2020

Abstract
The physics of variable mass systems is not as widely known as it should be; the required modifications to Newton’s laws and to the Euler–Lagrange equation are here outlined with a simple example of a chain lifted by a balloon. The confusion surrounding this subject is clarified, and a useful technique for avoiding the pitfalls of variable mass analysis is presented.
Hydrothermal synthesis of SrFe12O19 nanoparticles: effect of the choice of base and base concentration
Authors: Eikeland Anna Zink , Hölscher Jennifer , Christensen Mogens 
Published: December 2020

Abstract
Platelet shaped strontium hexaferrite (SrFe12O19) crystallites were hydrothermally synthesized in an autoclave to study the effect of (a) Fe/Sr molar ratio, (b) choice of base NaOH/KOH and (c) base concentration. The influence of these parameters on the final product is evaluated with regards to phase composition, structure and magnetic properties. Rietveld refinements were performed on powder x-ray diffraction (PXRD) data to determine the phase composition, structural changes, crystallite sizes, and preferred orientation, while the magnetic properties were measured using a vibrating sample magnetometer. When NaOH is used as the base, the samples consist mostly (>95 wt.%) of SrFe12O19 up to the same molar ratio of Fe/Sr = 8, independent of the concentration of the base. In contrast, when using KOH, the phase composition depends on both the molar ratio of Fe/Sr and the concentration of KOH. High concentrations of Sr2+ and OH− (Fe/Sr = 1 and OH−/NO3
− = 4) result in the growth of wide crystallites (>400 nm). The thickness of the crystallites are in all cases around 40 nm causing the crystallites to have an anisotropic shape, which can align without applying an external magnetic field. In the case of KOH as base instead of NaOH, an expansion of the unit cell is observed, which can be attributed to K+ substituting Sr2+ in the structure. This is corroborated by increasing microstrain when increasing the KOH/NO3
− ratio. Variations in the observed coercivity may be attributed to substitution of Sr2+ by K+. The present study illustrates that meticulous control of all reaction parameters and a meticulous analysis of the crystal structure is key for preparing and understanding hard-magnetic SrFe12O19.