1,720,977 research outputs found
The use of Habitat Suitability Models in Conservation Planning
Full text linkThe work of this thesis aims to highlight the contribution that suitability models can give to
global scale conservation biology. Four main themes will be approached: Opportunity offered
by model improvements; Information added to analyses on current protection status;
contribution offered to priority setting; information added to long term efficiency in
conservation plan
Projected Global Loss of Mammal Habitat Due to Land-Use and Climate Change
Full text linkHuman pressure on the environment is driving a global decline of biodiversity. Anticipating whether this trend can be reverted under future scenarios is key to supporting policy decisions. We used the InSiGHTS framework to model the impacts of land-use and climate change on future habitat availability for 2,827 terrestrial mammals at 15 arcmin resolution under five contrasting global scenarios based on combinations of representative concentration pathways and shared socio-economic pathways between 2015 and 2050. Mammal habitat declined globally by 5%–16% depending on the scenario. Africa (with declines up to 25%) and South America were the most affected regions. African insectivores, primates, Australian carnivorous marsupials and marsupial moles, and South American opossums declined the most. Tackling this loss would require a mix of actions across scales, including a global shift toward sustainability, addressing land-use change in sub-Saharan Africa, and helping endemic species track climate change in South America
Ecological correlates of dispersal distance in terrestrial mammals
No full textDispersal distance in mammals is a fundamental information for several ecological and conservation applications. Although dispersal can depend on many intrinsic and extrinsic factors, in recent years many studies have shown that it scales with body size and home range area. However, the role of further ecological correlates to distance travelled is still unclear and the predictive models proposed so far have suffered from small sample size and lack of error estimates. This reduces the practical relevance of the models for ecological and conservation applications. We conducted a comprehensive meta-analysis on 327 studies on the dispersal of 164 mammal species, and performed linear and non-linear regression analyses to explore the relationships of body size and home range area with dispersal distance. We tested the effect of various life history traits and ecological factors on the relationships and performed a sensitivity analysis to evaluate the robustness of the models to sample size. The linear relationships of both home range and body size with dispersal distance were influenced by various life history traits and ecological factors. We developed allometric functions to estimate species dispersal distance based on different predictors and life history traits. Linear models representing the relationship between dispersal distance and body size or home range area received good support; however logistic models better approximates both relationships. Despite receiving less support than a logistic curve, a linear model between dispersal and home range is a good approximation for applicative purposes. Sensitivity analysis showed that our results are robust to subsampling of the original dataset until a sample of 40 species. Our empirical models have the potential to improve theoretical and applied population biology studies by extending the applicability and improving the accuracy of dispersal distance estimation to a large number of mammals
Effects of Consumptive Water Use on Biodiversity in Wetlands of International Importance
No full textWetlands are complex ecosystems that harbor a large diversity of species. Wetlands are among the most threatened ecosystems on our planet, due to human influences such as conversion and drainage. We assessed impacts from water consumption on the species richness of waterbirds, nonresidential birds, water-dependent mammals, reptiles and amphibians in wetlands, considering a larger number of taxa than previous life cycle impact assessment methods. Effect factors (EF) were derived for 1184 wetlands of international importance. EFs quantify the number of global species-equivalents lost per m(2) of wetland area loss. Vulnerability and range size of species were included to reflect conservation values. Further, we derived spatially explicit characterization factors (CFs) that distinguish between surface water and groundwater consumption. All relevant watershed areas that are contributing to feeding the respective wetlands were determined for CF applications. In an example of rose production, we compared damages of water consumption in Kenya and The Netherlands. In both cases, the impact was largest for waterbirds. The total impact from water consumption in Kenya was 67 times larger than in The Netherlands, due to larger species richness and species' vulnerability in Kenya, as well as more arid conditions and larger amounts of water consumed
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
What spatial data do we need to develop global mammal conservation strategies?
No full textSpatial data on species distributions are available in two main forms, point locations and distribution maps (polygon ranges and grids). The first are often temporally and spatially biased, and too discontinuous, to be useful (untransformed) in spatial analyses. A variety of modelling approaches are used to transform point locations into maps. We discuss the attributes that point location data and distribution maps must satisfy in order to be useful in conservation planning. We recommend that before point location data are used to produce and/or evaluate distribution models, the dataset should be assessed under a set of criteria, including sample size, age of data, environmental/geographical coverage, independence, accuracy, time relevance and (often forgotten) representation of areas of permanent and natural presence of the species. Distribution maps must satisfy additional attributes if used for conservation analyses and strategies, including minimizing commission and omission errors, credibility of the source/assessors and availability for public screening. We review currently available databases for mammals globally and show that they are highly variable in complying with these attributes. The heterogeneity and weakness of spatial data seriously constrain their utility to global and also sub-global scale conservation analyses
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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