1,721,268 research outputs found
Data from: Quantifying and linking mechanism scenarios to invasive species impact
No full textPlant species invasion represents one of the major drivers of biodiversity change globally, yet there is confusion about the nature of non-indigenous species (NIS) impact. This stems from differing notions of what constitutes invasive species impact and the scales at which it should be assessed. At local scales, the mechanisms of impact on local competitors can be classified into four scenarios: 1) minimal impact from NIS inhabiting unique niches; 2) neutral impact spread across the community and proportional to NIS abundance; 3) targeted impact on a small number of competitors with overlapping niches; and 4) pervasive impact that is disproportionate to NIS abundance and caused by modifications that filter out other species. I developed a statistical test to distinguish these four mechanism scenarios based on plant community rank-abundance curves and then created a scale-independent standardized impact score. Using an example long-term dataset, that has high native plant diversity and an abundance gradient of the invasive vine, Vincetoxicum rossicum, I show that impact resulted in either targeted or pervasive extirpations. Regardless of whether NIS impact is neutral, targeted, or pervasive, the net outcome will be the homogenization of ecosystems and reduced biodiversity at larger scales, perhaps reducing ecosystem resilience. The framework and statistical evaluation of impact presented in this paper provide researchers and managers with an objective approach to quantifying NIS impact and prioritizing species for further management actions.Funding provided by: Natural Sciences and Engineering Research Council of CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038Award Number:Twenty-five, 1x1 m2 plots at each of 14 sites at the Rouge Urban National Park in Canada. We estimated percent cover and identify plant species in 2013 and 2019. (for methodological details, see: Livingstone et al. 2020).
Livingstone, Stuart; Isaac, Marney; Cadotte, Marc (2020), Data from: Invasive dominance and resident diversity: unpacking the impact of plant invasion on biodiversity and ecosystem function, Dryad, Dataset, https://doi.org/10.5061/dryad.dncjsxkw
Invasion drives plant diversity loss through competition and ecosystem modification
No full text1. Although invasive plants increasingly contribute to the current biodiversity crisis, the mechanisms through which they impact native communities are still poorly understood. Community ecology theory has emphasized direct competitive displacement over common resources, but invasion-driven ecosystem modifications, such as altered soil pH, might also have consequences for plant diversity. However, the relative importance of ecosystem modification compared to direct resource competition has rarely been tested.
2. Here we studied the invasive vine Vincetoxicum rossicum across invaded meadows in southern Ontario, Canada. In each meadow site, we quantified: 1) the strength of impact on the resident plant community, 2) the potential for competition with resident species (as the degree of niche-dissimilarity and competitive superiority to the residents based on their functional traits), and 3) the amount of ecosystem modification related to invasion.
3. We found that impacts on plant biodiversity were more negative where the invader had greater potential to competitively displace species (because it had a similar niche as the residents or was competitively superior), but also where it strongly altered soil N pools, moisture and pH.
4. Synthesis. Our case study suggests that, while competition is undoubtedly an important driver of invasion impact, ecosystem modifications can have cascading effects on plant communities, thereby magnifying the impacts of biological invasions
Solving environmental problems in the Anthropocene : the need to bring novel theoretical advances into the applied ecology fold
Full text linkThe romanticized view of untouched, pristine nature is fast disappearing. From pollution and deforestation, to the introduction of non-native species, we now live in a world where almost every major ecosystem has been impacted by human activities. Geologists have now recognized this wholesale alteration of the Earth’s environment as sufficient to demark our current era as a new geological epoch – the Anthropocene (Zalasiewicz et al. 2008).Fil: Cadotte, Marc W.. University of Toronto; CanadáFil: Barlow, Jos. Lancaster University; Reino Unido. Museu Paraense Emilio Goeldi; BrasilFil: Nuñez, Martin Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Pettorelli, Nathalie. The Zoological Society Of London; Reino UnidoFil: Stephens, Philip A.. University Of Durham; Reino Unid
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Species wood density and the location of planted seedlings drive early-stage seedling survival during tropical forest restoration
No full text1. The success of restoration projects is known to vary widely, with outcomes relating to numerous biotic and abiotic factors. Though many studies have examined the factors associated with long-term restoration success, few have examined which factors impact the establishment of restoration plantings
Robust study design is as important on the social as it is on the ecological side of applied ecological research
Full text link1. The effective management of natural systems often requires resource users to change their behaviour. This has led to many applied ecologists using research tools developed by social scientists. This comes with challenges as ecologists often lack relevant disciplinary training.
2. Using an example from the current issue of Journal of Applied Ecology that investigated how conservation interventions influenced conservation outcomes, we discuss the challenges of conducting interdisciplinary science. We illustrate our points using examples from research investigating the role of law enforcement and outreach activities in limiting illegal poaching
and the application of the theory of planned behaviour to conservation.
3. Synthesis and applications. Interdisciplinary research requires equal rigour to be applied to ecological and social aspects. Researchers with a natural science background need to access expertise and training in the principles of social science research design and methodology, in order to permit a more balanced interdisciplinary understanding of social–ecological system
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Rapid collapse of a sub-Antarctic alpine ecosystem: The role of climate and pathogens
No full textEcosystem change is predicted to become more prevalent with climate change. Widespread dieback of cushion plants and bryophytes in alpine fellfield on Macquarie Island may represent such change. Loss of the keystone endemic cushion plant, Azorella macquariensis, was so severe that it has been declared critically endangered. We document the dieback and its extent. Due to the rapidity of the event, we sought to infer causes by testing two mechanistic hypotheses: (i) that extensive dieback was due to a pathogen and (ii) that dieback was a consequence of a change in climate that induced stress in several susceptible species. We searched for pathogens using both conventional and next-generation sequencing techniques. We examined plant functional morphology in conjunction with a long-term climate record of plant-relevant climate parameters to determine whether environmental conditions had become inimical for A.\ua0macquariensis. Dieback was found across the entire range of A.\ua0macquariensis. A survey found 88% of 115 stratified/ random sites contained affected cushions and 84% contained dead bryophytes. Within-site dieback increased over time. No conclusive evidence that A.\ua0macquariensis deaths were caused by a definitive disease-causing pathogen emerged. However, the presence of bacterial, fungal and oomycete taxa, some potentially pathogenic, suggested that stressed cushions could become susceptible to infection. The primary cause of collapse is suspected failure of A.\ua0macquariensis and other fellfield species to withstand recent decadal changes in summer water availability. Increased wind speed, sunshine hours and evapotranspiration resulted in accumulated deficits of plant available water spanning 17\ua0years (1992-2008). High vulnerability to interrupted water supply was consistent with functional morphology of A.\ua0macquariensis, and climate change has altered the species' environment from wet and misty to one subject to periods of drying. Synthesis and applications. With alpine fellfield dieback baseline data on Macquarie Island established, future monitoring will determine whether this event represents a transient, decadal-level change in the ecosystem or the initiation of a climate-related, transformation away from an Azorella-dominated fellfield ecosystem. That mechanisms driving ecosystem collapse were complex and multiple stressors appeared to be impacting cumulatively may be relevant to other locations. With alpine fellfield dieback baseline data on Macquarie Island established, future monitoring will determine whether this event represents a transient, decadal-level change in the ecosystem or the initiation of a climate-related, transformation away from an Azorella-dominated fellfield ecosystem. That mechanisms driving ecosystem collapse were complex and multiple stressors appeared to be impacting cumulatively may be relevant to other locations
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