1,721,060 research outputs found
Time-lagged effects of habitat fragmentation on terrestrial mammals in Madagascar
Get PDFBiodiversity is severely threatened by habitat destruction. As a consquence of habitat destruction, the remaining habitat becomes more fragmented. This results in time-lagged population extirpations in remaining fragments when these are too small to support populations in the long term. If these time-lagged effects are ignored, the long-term impacts of habitat loss and fragmentation will be underestimated. We quantified the magnitude of time-lagged effects of habitat fragmentation for 157 nonvolant terrestrial mammal species in Madagascar, one of the biodiversity hotspots with the highest rates of habitat loss and fragmentation. We refined species' geographic ranges based on habitat preferences and elevation limits and then estimated which habitat fragments were too small to support a population for at least 100 years given stochastic population fluctuations. We also evaluated whether time-lagged effects would change the threat status of species according to the International Union for the Conservation of Nature Red List assessment framework. We used allometric relationships to obtain the population parameters required to simulate the population dynamics of each species, and we quantified the consequences of uncertainty in these parameter estimates by repeating the analyses with a range of plausible parameter values. Based on the median outcomes, we found that for 34 species (22% of the 157 species) at least 10% of their current habitat contained unviable populations. Eight species (5%) had a higher threat status when accounting for time-lagged effects. Based on 0.95-quantile values, following a precautionary principle, for 108 species (69%) at least 10% of their habitat contained unviable populations, and 51 species (32%) had a higher threat status. Our results highlight the need to preserve continuous habitat and improve connectivity between habitat fragments. Moreover, our findings may help to identify species for which time-lagged effects are most severe and which may thus benefit the most from conservation actions. ARTICLE IMPACT STATEMENT: For 22% of endemic terrestrial mammals in Madagascar, at least 10% of the remaining habitat is too fragmented to support viable populations
Futurestreams dataset
No full textRepository of discharge and water temperature scenarios derived from 5 CMIP5 GCMs from the ISI-MIP project computed by the global water balance model PCRGLOBWB and the global water temperature model DynWat.
Data are provided on a weekly temporal resolution and 10km spatial resolution. 4 Representative Concentration Pathways are presented, RCP2.6, RCP4.5, RCP6.0 and RCP8.5, up to 2099. The historical simulations are also provide for 1976 - 2005. A historical simulation derived from E2O reanalysis data is also provided.
Data access is currently restricted, and will become directly available once the accompanying Data Descriptor (currently under review) is published.
Contact persons are:
- Joyce Bosmans ([email protected])
- Niko Wanders ([email protected]
Understanding species responses to habitat change across scales using the countryside species-area relationship : [kumulative Dissertation]
No full textLandnutzungswandel ist zweifellos ein Hauptgrund für Biodiversitätswandel und beeinflusst die Muster von Artenvielfalt von der lokalen bis zur globalen Ebene. Dennoch wird in aktuellen Untersuchungen von Biodiversitätswandel häufig vernachlässigt, dass Arten häufig nicht von Habitatverlust sondern von Habitatwandel betroffen sind und dass nicht alle Arten gleichermaßen auf Habitatwandel reagieren. Hier erweitere ich unser Verständnis von der Reaktion von Arten auf Habitatwandel und verfeinere eine Methode mit der Biodiversitätswandel auf verschiedenen räumlichen Skalen vorhergesagt werden kann.Land use change is an undisputed major driver of biodiversity change, affecting species richness patterns from local to global scales. Yet, current assessments of biodiversity change frequently neglect that species often face habitat change instead of habitat loss, and that not all species respond equally to it. Here, I expand our understanding of species responses to habitat change, while refining a tool to predict biodiversity change across scales. The countryside SAR framework presented here emerges as a unifying framework that retains the heuristic property of the classic SAR model, while being capable of accounting for the wider effects of the landscape on biodiversity. Above all, conservation and prioritization strategies that consider a broad spectrum of habitat responses from multiple species groups have the potential to be more successful in safeguarding the multiple levels of biodiversity
Temperature-related biodiversity change across temperate marine and terrestrial systems
No full textClimate change is reshaping global biodiversity as species respond to changing temperatures. However, the net effects of climate-driven species redistribution on local assemblage diversity remain unknown. Here, we relate trends in species richness and abundance from 21,500 terrestrial and marine assemblage time series across temperate regions (23.5–60.0° latitude) to changes in air or sea surface temperature. We find a strong coupling between biodiversity and temperature changes in the marine realm, where species richness mostly increases with warming. However, biodiversity responses are conditional on the baseline climate, such that in initially warmer locations richness increase is more pronounced while abundance declines with warming. In contrast, we do not detect systematic temperature-related richness or abundance trends on land, despite a greater magnitude of warming. As the world is committed to further warming, substantial challenges remain in maintaining local biodiversity amongst the non-uniform inflow and outflow of ‘climate migrants’. Temperature-driven community restructuring is especially evident in the ocean, whereas climatic debt may be accumulating on land.</p
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
Ecosystem services across Europe. D4.2 Current and future natural capital and ecosystem services
No full textThe EU Biodiversity Strategy for 2030 aims to put biodiversity on the path to recovery by 2030. A key component of the Strategy is the development of a coherent Trans-European Nature Network (TEN-N), to increase the coherence of the existing network of Natura 2000 sites and other nationally designated protected areas by addressing gaps in the coverage of priority habitats and species. The NaturaConnect project supports the design of a TEN-N, amongst others by designing and developing a future-proof blueprint through spatial conservation prioritisation. In this context, it is key to consider multifunctionality, that is, to ensure that the TEN-N addresses not just ecological representativeness but also the ability of nature to meet societal needs or demands through the provisioning of ecosystem services (ES).The present deliverable of NaturaConnect (D4.2) provides a set of ES layers aligned with present and potential future land and climate conditions, designed for use in spatial conservation prioritisation. We generated layers for a selection of regulating and cultural ES, with a focus on climate change mitigation (carbon storage and sequestration) and adaptation (e.g., improving soil retention considering expected increases in the magnitude and frequency of heavy rainfall events), food security (crop pollination, pest control), as well as the capacity of nature to improve people’s mental and physical health by offering opportunities for recreation and experiencing nature. We quantified all ES based on common input data with regard to land systems and climate, to ensure compatibility. Where possible and relevant, we considered ES supply, demand and flow separately.We quantified carbon storage and sequestration according to a book-keeping approach, assigning typical values of the amounts of carbon stored (MgC/ha) and sequestred (MgC/ha/yr) to each land system. We considered only the supply of carbon storage and sequestration, reasoning that the demand for this service is global and considerably larger than the supply. The amounts of carbon stored and sequestered are based on values from the scientific literature and existing datasets which indicate how much carbon is stored and sequestered per land system, and how this would change if the land system underwent a transition (e.g. from forest to cropland). Output maps revealed that forests and wetlands, especially in northern Europe, are characterised by the highest carbon storage and sequestration rates. Croplands are characterised by negative sequestration rates, hence act as sources of emission.We quantified the supply of soil retention based on the ability of vegetation to prevent soil erosion induced by heavy rainfall events, using the universal soil loss equation (RUSLE) to assess soil erosion. Specifically, we quantified the soil retention service (t/ha/yr) based on how much soil loss is prevented by the current vegetation cover, defined per land system, as compared to a counterfactual situation without vegetation. We also quantified the potential additional prevention of soil loss (t/ha/yr) if the vegetation were restored from its current state to a maximum cover. We defined soil retention demand based on the amount of soil loss to be prevented in order to ensure that losses would not exceed the natural soil formation rate. Output maps revealed hotspots of actual and potential additional soil retention demand, supply and flow mainly in mountainous regions, reflecting the key role of terrain slope in determining erodibility as well as the importance of vegetation for reducing it.We modelled the supply of crop pollination based on the potential of pollinator habitat to provide pollinators and the demand based on the presence of nearby cropland in need of pollination. Using observational data from scientific literature and existing databases, we first established a quantitative relationship that estimates wild pollinator abundance in pollinator-dependent cropland (n/m2) based on various ecologically relevant covariates, including the proportion of pollinator habitat within 3 km from the cropland cell. We used this relationship to map pollinator abundance in croplands across Europe, which we subsequently attributed to the cells with pollinator habitat (i.e., the service-providing units) within 3 km from each focal cropland cell, to facilitate application of the model results in spatial conservation prioritisation. Output maps reveal high pollinator abundance values for habitat cells located in areas dominated by cropland, as these habitat cells serve multiple cropland cells, and low values when multiple habitat cells surround a single cropland cell.To assess forest recreational potential, we developed a spatial model based on people’s preferences for forests with different structural characteristics, expressed through the willingness-to-travel (WTT) indicator. Using data from a large-scale visual choice experiment conducted in 12 European countries, we estimated WTT as a function of forest management classes, combined with spatial data on canopy height and tree species diversity. The result is the first Europe-wide map of forest recreational potential, revealing particularly high values in regions with taller, more diverse, and structurally complex forests.We modelled landscape recreational potential based on the recreational opportunities associated with the land systems surrounding each grid cell. We quantify supply based on the number and diversity of land systems that provide recreational opportunities within a given distance from each focal grid cell, and the demand based on the number of potential beneficiaries within a certain distance. Well-supplied areas encompass, among others, the western Iberian peninsula (Portugal) and the Pyrenees, the Auvergne, Rhone-Alpes, and the Provence-Alpes-Cote d’Azur in France, Ireland, Scotland, the Alps and Dinarides as well as the Baltics (Estonia, Latvia), and large parts of the Scandinavian Peninsula and Finland. Demand is particularly high for the European megacities and the various conurbations and metropolitan areas.Finally, we modelled nine regulating and five cultural species-based ecosystem services provided by terrestrial vertebrate species, including, among others, carrion removal, control of pest species (bark beetles, mosquitoes) and evolutionary heritage. For each service, we modelled supply based on the number of specific vertebrate species able to provide a certain service and demand based on the land system in a grid cell assumed to be in need of the service. Resulting maps show distinct patterns for the different ES, revealing the richness of provider species in areas with demand for each service.The ES layers described in this report were primarily developed to support broad-scale spatial conservation or restoration prioritisation efforts, i.e., efforts to identify and rank planning units (in this case grid cells) based on features considered in need of conservation or restoration. In the NaturaConnect project, the ES layers will be used together with layers of other relevant variables, such as biodiversity features, habitat connectivity and the costs of conservation, to identify pan-European conservation priorities. Beyond NaturaConnect, we expect our layers to be useful in particular for national and sub-national governmental and non-state authorities responsible for land planning, as our maps can help in identifying sites where ES supply or flow are high (indicating a need for conservation) or where demand is high yet supply is low (indicating a need for restoration). This way, we expect the layers and underlying code to be useful for informing land management and conservation planning also beyond the project
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
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