1,720,999 research outputs found
High resolution land use maps from 1960 to 2100
No full textAnthropogenic land-use and land-cover change is a major driver of climate change and biodiversity loss. Land-use and land-cover change also leads to changes in the spatial pattern of Earth’s landscapes, which have further negative impacts on environmental processes. For example, deforestation can increase the distance between forest patches, making it harder for species to move between them. Harmonized land-use and land-cover datasets contain standardized maps of global land use and land cover through time, without any gaps or sudden changes between historic and future periods. Harmonized datasets are important for addressing the negative consequences of land-use and land-cover change because they are used in environmental models to predict its impacts on processes such as carbon emissions and species movement. However, existing harmonized datasets do not project the spatial pattern of land-use and land-cover change into the future and have coarse resolutions that do not match the fine scales on which environmental processes occur. We present a high-resolution, global-scale harmonized land-use and land-cover dataset for five future scenarios that spans the period 1960–2100. The spatial pattern of land-use and land-cover change was accounted for when generating the future maps to ensure that they have realistic spatial patterns. This new dataset will be suitable for integration with a range of environmental models, such as those that model biodiversity, climate, and fire, and therefore offers an important tool for understanding the effects of land-use and land-cover change and developing solutions to environmental challenges
Prioritising conservation actions for biodiversity: Lessening the impact from habitat fragmentation and climate change
No full textThe interacting impacts of habitat fragmentation and climate change present a substantial threat for biodiversity, constituting a ‘deadly anthropogenic cocktail’. A range of conservation actions has been proposed to allow biodiversity to respond to those environmental changes. However, determining the relative effectiveness of these actions has been hampered by incomplete evidence. Empirical studies have provided important insights to inform conservation, but the challenge of considering multiple actions at large spatial and temporal scales is considerable. We adopt an individual-based modelling approach to qualitatively assess the effectiveness of alternative conservation actions in facilitating range expansion and patch occupancy for eight virtual species. We test actions to: (i) improve the quality of existing habitat patches, (ii) increase the permeability of the surrounding matrix, (iii) restore degraded habitat, (iv) create new habitat patches to form stepping-stones or (v) create new habitat to enlarge existing habitat patches. These actions are systematically applied to six real landscapes of the UK, which differ in their degree of habitat fragmentation and availability. Creating new habitat close to existing patches typically provides the strongest benefits for both range expansion and patch occupancy across species and landscapes. However, some landscapes may be so degraded that even under unrealistically high levels of management action, species' performances cannot be rescued. We identify that it is possible to develop a triage of conservation actions at the landscape, species and investment level, thereby providing timely evidence to inform action on the ground to lessen the hangover from the deadly anthropogenic cocktail.</p
A multi-species modelling approach to examine the impact of alternative climate change adaptation strategies on range shifting ability in a fragmented landscape
No full textAn individual-based model of animal dispersal and population dynamics was used to test the effects of different climate change adaptation strategies on species range shifting ability, namely the improvement of existing habitat, restoration of low quality habitat and creation of new habitat. These strategies were implemented on a landscape typical of fragmentation in the United Kingdom using spatial rules to differentiate between the allocation of strategies adjacent to or away from existing habitat patches. The total area being managed in the landscape was set at realistic levels based on recent habitat management trends. Eight species were parameterised to broadly represent different stage structure, population densities and modes of dispersal. Simulations were initialised with the species occupying 20% of the landscape and run for 100 years. As would be expected for a range of real taxa, range shifting abilities were dramatically different. This translated into large differences in their responses to the adaptation strategies. With conservative (0.5%) estimates of the area prescribed for climate change adaptation, few species display noticeable improvements in their range shifting, demonstrating the need for greater investment in future adaptation. With a larger (1%) prescribed area, greater range shifting improvements were found, although results were still species-specific. It was found that increasing the size of small existing habitat patches was the best way to promote range shifting, and that the creation of new stepping stone features, whilst beneficial to some species, did not have such broad effect across different species
Simulating different strategies to control the invasive tree Ligustrum lucidum using the RangeShifter platform
No full textThese folders contain all the inputs (batch files) to simulate alternative strategies for containing the invasion of the Asian tree Ligustrum lucidum at the expansion front. The simulations were conducted utilising a customised version of the individual-based spatially explicit modelling platform RangeShifter v2.0 (Bocedi et al., 2021; https://rangeshifter.github.io/). Across different sets of simulations, we varied the number of life stages and sites targeted. We additionally investigated how changing the management strategy over time affected outcomes. A total of 3 simulation experiments were carried out. The work was carried out as part of the Latin American Biodiversity Programme as part of the Newton Fund (NE/S011641/1), with contributions from NERC (UK), the Argentine National Scientific & Technical Research Council (CONICET,-201974-APN-DIR#CONICET) and 2022GCBCCONTAIN.- Invasive alien species management to decrease impacts on biodiversity, rural poverty and carbon storage -Folder 1: Parametrization of the Individual Base Model -Folder 2: Parametrization of Experiment 1: removing different life stages and varying the number of cells targeted each year for 30 years -Folder 3: Parametrization of Experiment 2: removing all stages (S1 to S4) to evaluate the effect of varying the number of cells targeted per year -Folder 4: Parametrization of Experiment 3: switching from removing all stages to removing only S1 and S2 after five years of removal would maintain effective control of the population for 15 yearsFil: Montti, Lia Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palmer, Stephen C.F.. University of Aberdeen; Reino UnidoFil: Powell, Priscila Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Burslem, David F.R.P.. University of Aberdeen; Reino UnidoFil: Travis, Justin M.J.. University of Aberdeen; Reino UnidoFil: Ponchon, Aurore. University of Aberdeen; Reino Unid
Predicting the outcomes of management strategies for controlling invasive river fishes using individual‐based models
No full textThe effects of biological invasions on native biodiversity have resulted in a range of policy and management initiatives to minimize their impacts. Although management options for invasive species include eradication and population control, empirical knowledge is limited on how different management strategies affect invasion outcomes.An individual-based model (IBM) was developed to predict how different removal (‘culling’) strategies affected the abundance and spatial distribution of a virtual, small-bodied, r-selected alien fish (based on bitterling, Rhodeus sericeus) across three types of virtual river catchments (low/intermediate/high branching tributary configurations). It was then applied to nine virtual species of varying life-history traits (r- to K-selected) and dispersal abilities (slow/intermediate/fast) to identify trade-offs between the management effort applied in the strategies (as culling rate and the number of patches it was applied to) and their predicted effects. It was also applied to a real-world example, bitterling in the River Great Ouse, England.The IBM predicted that removal efforts were more effective when applied to recently colonized patches. Increasing the cull rate (proportion of individuals removed per patch), and its spatial extent was effective at controlling the invasive population; when both were relatively high, population eradication was predicted.The characteristics of the nine virtual species were the main source of variation in their predicted abundance and spatial distribution. No species were eradicated at cull rates below 70%. Eradication at higher cull rates depended on dispersal ability; slow dispersers required lower rates than fast dispersers, and the latter rapidly recolonized at low cull rates. The trade-offs between management effort and the outcomes of the invasion were, generally, optimal when intermediate effort was applied to intermediate numbers of patches. In the Great Ouse, model predictions were that management interventions could restrict bitterling distribution by 2045 to 21% of the catchment (versus 90% occupancy without management).Synthesis and application. This IBM predicted how management efforts can be optimized against invasive fishes, providing a strong complement to risk assessments. We demonstrated that for a range of species' characteristics, culling can control and even eradicate invasive fish, but only if consistent and relatively high effort is applied
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
Land cover maps of Sierra de San Javier, Tucumán, Argentina, 1986-2018
No full textLand cover maps of Sierra de San Javier, Tucumán, Argentina, 1986-2018 This series of Land Cover Maps (LCM) was built using atmospherically corrected surface reflectance (TIER 1) Landsat 5 ETM and Landsat 8 OLI images, with less than 10% of cloud cover. A collection of Landsat 5 (1986, 1990, 2010) and Landsat 8 (2018) images from June to December, dividing images of each year in two periods were selected: dry (June to September) and wet seasons (September to December), to take advantage of seasonal phenological differences between native and exotic (L. lucidum) forests. Image collections were then combined by calculating the median of all values at each pixel across the stack of all matching bands per year, obtaining two images per year (dry/wet season). Land cover maps were constructed by applying the machine learning algorithm Random Forest (RF), based on an ensemble of classification trees, fully run on the Google Earth Engine platform. The maps include 8 land-use categories: Subtropical montane forest (SMF, category 40) Dry forest (DF, category 41) Montane grasslands (MGr, category 30) Anthropogenic grasslands and shrubland used for livestock and temporary agriculture, a mixed class including also herbaceous agriculture and low-density urban areas (AGr, category 31 ) Sugar cane (SC, category 51) Citrus plantations, mostly lemon (CP, category 50) High/medium-density urban areas (URB, category 11). Ligustrum lucidum (L, category 42). The extent of the maps are between -65,500 to -65.160 latitude to -26.600 to -26.970 longitude, GCS_WGS1984 and 30 x 30 m of resolution.Fil: Powell, Priscila Ana. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Gutiérrez Angonese, Jorgelina. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Burslem, David. University of Aberdeen; Reino UnidoFil: Travis , Justin M.J.. University of Aberdeen; Reino UnidoFil: Jiménez, Yohana Gisell. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Montti, Lia Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin
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
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