1,720,953 research outputs found
Vegetation Cover Dynamics And The Environmental Threats To Biodiversity Conservation In Free State National Botanical Garden, South Africa
Get PDFThesisThe conservation gardens under South African Biodiversity Institute (SANBI) preserve biodiversity areas with unique and threatened vegetation types including national priority Critical Biodiversity Areas (CBA’s). The mandate of SANBI is to champion the exploration, conservation, appreciation, and enjoyment of South Africa’s exceptionally rich biodiversity for all people. Since the SANBI mandate emphasises sustainable biodiversity conservation, however, there were no studies that have quantitatively appraised the biodiversity conservation value and natural phenomena dynamics over time for different SANBI conservation gardens. This study determined the dynamics of the vegetation cover over a 30-year period (1987-2017) and potential environmental drivers of change in Free State National Botanical Garden (FSNBG). The FSNBG is located in the broader southern African grassland biome that is under huge conservation threats in South Africa. The FSNBG preserved national priority for biodiversity conservation (CBA1) in South Africa: the “Bloemfontein Karroid Shrubland”. The study applied the remote sensing technology and Geographical Information System (GIS) imagery to analyse the spatial vegetation cover changes that occurred over 30-years using 10 year’s intervals.
Overall study results show that vegetation cover of the study area significantly increased (in term of woody biomass) over the 30 year period, partly attributed to the combination of factors, which include severe droughts and the rise of CO2 concentrations in the atmosphere. In addition, it was possible that absence of the biophysical disturbance such as fire and browsers in the natural vegetation to suppressed wood species has encourage encroachment of woody cover species. Using Normalized Difference Vegetation Index (NDVI) approach, the vegetation of FNSBG was divided into four categories, namely: Dense vegetation, Moderate vegetation, Sparse vegetation and open soil. Overall, the sparse vegetation cover significantly decreased over time (R2 = - 0.29). Similarly, the moderate vegetation cover increased by 25.1 ha while dense vegetation also increased by 8.6 ha. However, the bare soil cover was found to be relatively consistent over the 30-year period.
Since the use of the remote sensing and GIS imagery could not clearly validate the current ecological status of CBA1 vegetation type, the manual field sampling approach was used looking into documenting the typical plant species provided by Mucina and Rutherford (2006); and measuring the vegetation cover. Vegetation cover of CBA1 was relatively high (i.e., 79.6 ± 15.9%); and this was above the minimum threshold of 60% habitat intactness reported to represent the habitat functionality that is normal although overall integrity is reduced. The existence of CBA1 vegetation type was supported by a record of 27 plant species out of 77 species documented as typical in the key descriptions provided by Mucina and Rutherford (2006). Major conservation threats entailed of 27 invasive alien plant species, human settlement encroachment have reduced the ecological buffer zone of FSNBG by 18% (119.07 ha) in the past 18 year; and 10 pests and pathogens that were interspersed in different vegetation patches of the study site. The observed changes suggested a need for regular vegetation monitoring of CBA1 vegetation type to manage the prevailing conservation threats that could have impact to ecological integrity.
Animal-plant mutualisms are important for the maintenance of both animal and plant population since both participating partners’ benefit. The phenology of seed dispersal is critical to the successful recruitment of species since dispersed seeds require conducive conditions for germination. Having noted the increasing bush encroachment in FSNBG in the past 30 years, the study also investigated the seed dispersal phenology and the potential influencing factors for the encroaching tree/shrub species of FSNBG focusing on biotic interaction of flesh fruits resource foraged by birds as study model. During fieldwork sampling for the seed deposited by birds in the 17 roosting sites, I collected a total of 22 161 seeds belonging to 14 native and non-native tree/shrub species. It was found that black and red fruits were more preferred by birds since most of the dispersed tree/shrub species had those colours and attracted 22 resident and colonial migratory frugivorous birds. I found that 80% of the bird-ingested and dispersed seeds of many tree/shrub species were collected between March and July. Two species: Ehreta rigida and Searsia lancea, displayed relatively short fruiting peak times between August and December when other fruits were scarce. Whereas the observed two fruiting patterns could reduce the competition for seed dispersal services between two groups of tree/shrub species, the resident and wintering birds are also likely to benefit substance in food resources. In addition, it was found that frugivorous birds adapt to localised foraging patterns and to limited fruit diversity. It was concluded that the highly preferred tree/shrub species are likely drivers of the reported bush encroachment in FSNBG.
Frugivorous birds disperse seed away from parent plant to new microsites that have relatively lower competition for the resources, and ingested seeds get scarified during feeding on fruits and ingestion by birds. Therefore, the study also investigated whether bird-dispersed seeds benefit from improved germination after their passage through the bird’s gut and the potential impact of seed density on competition at the microsites. On the germination trail results of bird-ingested seeds versus manual depulped seeds, Ziziphus mucronata displayed the highest germination rate of all trees/shrubs yet frugivorous birds did not improve its seed germination. However, only S. lancea seeds had significantly high seed germination after passage through the avian digestive tract. The test experiments for seed competition during germination at the microsite showed that only Z. mucronata and Olea europaea subsp. africana displayed significant positive performance with increasing seed density. The study concluded that the tree/shrubs species with high germination could account for the observed bush encroachment in FSNBG. It was recommended that adaptive conservation management plan of FSNBG should include monitoring and prioritised bush encroachment control of those species
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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