1,721,084 research outputs found
Translating habitat class to land cover to map area of habitat of terrestrial vertebrates.
Full text linkArea of habitat (AOH) is defined as the "habitat available to a species, that is, habitat within its range" and is calculated by subtracting areas of unsuitable land cover and elevation from the range. The International Union for the Conservation of Nature (IUCN) Habitats Classification Scheme provides information on species habitat associations, and typically unvalidated expert opinion is used to match habitat to land-cover classes, which generates a source of uncertainty in AOH maps. We developed a data-driven method to translate IUCN habitat classes to land cover based on point locality data for 6986 species of terrestrial mammals, birds, amphibians, and reptiles. We extracted the land-cover class at each point locality and matched it to the IUCN habitat class or classes assigned to each species occurring there. Then, we modeled each land-cover class as a function of IUCN habitat with (SSG, using) logistic regression models. The resulting odds ratios were used to assess the strength of the association between each habitat and land-cover class. We then compared the performance of our data-driven model with those from a published translation table based on expert knowledge. We calculated the association between habitat classes and land-cover classes as a continuous variable, but to map AOH as binary presence or absence, it was necessary to apply a threshold of association. This threshold can be chosen by the user according to the required balance between omission and commission errors. Some habitats (e.g., forest and desert) were assigned to land-cover classes with more confidence than others (e.g., wetlands and artificial). The data-driven translation model and expert knowledge performed equally well, but the model provided greater standardization, objectivity, and repeatability. Furthermore, our approach allowed greater flexibility in the use of the results and uncertainty to be quantified. Our model can be modified for regional examinations and different taxonomic groups
Update or outdate: long-term viability of the IUCN Red List
No full textIt is estimated that the global yearly expenditure on biodiversity conservation action exceeds one billion U.S. dollars. One of the key tools for prioritizing conservation actions is the International Union for Conservation of Nature (IUCN) Red List, the most authoritative and comprehensive source of information on the global extinction risk of species (covering ca. 60,000 as of today). While IUCN's vision is to increase the taxonomic coverage of the Red List, no adequate plan exists to keep it up to date. As species assessments become outdated after 10 years under IUCN rules, our simulations reveal that with the limited budget currently available for reassessment, most of the Red Listing effort may be wasted soon. Indeed, 17% of the species' assessments are already outdated. To minimize the budget needed to keep assessments up to date in the Red List, we propose a mixed strategy of online reassessments and budget growth. We show that largely replacing workshops with online consultations is a more sustainable strategy that would save U.S. 2.8\ua0million per year (35% of the budget). Sharing the cost of such a strategy among Organization for Economic Co-operation and Development (OECD) countries (U.S. 156,000 per country per year) would ensure that the multimillion dollar spending based on the Red List remains effective in the long term
Area of Habitat maps for the world’s terrestrial birds and mammals
Full text linkMeasurement(s) Species Distributions Technology Type(s) Area of Habitat Factor Type(s) Habitat Sample Characteristic - Organism Mammalia • Aves Sample Characteristic - Environment Terrestrial Habitat
Threatened birds of the world 2004 species factsheets for globally threatened birds produced by BirdLife International, the official red listing authority for birds for the IUCN red list
No full text
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
A validation standard for area of habitat maps for terrestrial birds and mammals
Full text linkArea of habitat (AOH) is a deductive model which
maps the distribution of suitable habitats at suitable alti-
tudes for a species inside its broad geographical range. The
AOH maps have been validated using presence-only data for
small subsets of species for different taxonomic groups, but
no standard validation method exists when absence data are
not available. We develop a novel two-step validation pro-
tocol for AOH which includes first a model-based evalua-
tion of model prevalence (i.e, the proportion of suitable habi-
tat within a species’ range), and second a validation using
species point localities (presence-only) data. We applied the
protocol to AOH maps of terrestrial birds and mammals. In
the first step we built logistic regression models to predict ex-
pected model prevalence (the proportion of the range retained
as AOH) as a function of each species’ elevation range, mid-
point of elevation range, number of habitats, realm and, for
birds, seasonality. AOH maps with large differences between
observed and predicted model prevalence were identified as
outliers and used to identify a number of sources of system-
atic error which were then corrected when possible. For the
corrected AOH, only 1.7 % of AOH maps for birds and 2.3 %
of AOH maps for mammals were flagged as outliers in terms
of the difference between their observed and predicted model
prevalence. In the second step we calculated point preva-
lence, the proportion of point localities of a species falling in
pixels coded as suitable in the AOH map. We used 48 336 141
point localities for 4889 bird species and 107 061 point lo-
calities for 420 mammals. Where point prevalence exceeded
model prevalence, the AOH was a better reflection of species’
distribution than random selection. We also found that 4689
out of 4889 (95.9 %) AOH maps for birds, and 399 out of
420 (95.0 %) AOH maps for mammals were better than ran-
dom. Possible reasons for the poor performance of a small
proportion of AOH maps 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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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