16 research outputs found

    Evaluation of a potential umbrella species using favourability models: the case of the endangered little bustard (Tetrax tetrax) and steppe birds

    Full text link
    Farmland biodiversity is in alarming decline worldwide due to agriculture intensifcation. In this context, the umbrella species concept may help in better targeting conservation eforts, focusing on species whose requirements may best cover those of other components of biological communities. We test this idea using the little bustard (Tetrax tetrax), a strongly declining steppe bird depending on extensive agricultural landscapes of southwestern Europe, to explore the degree to which its habitat requirements can predict those of other sympatric endangered steppe birds. We use little bustard and other nine species distribution data at 10×10 km scale in Castilla-La Mancha (the most important region for the little bustard in Spain and the EU) and habitat favourability models to identify variables explaining little bustard favourability that can robustly predict habitat favourability also for the other nine species. Models ftted with variables explaining little bustard favourability and applied on co-occurring species yielded varying performance results. Models support the role of the little bustard as umbrella species only for a part of the steppe bird community, and more precisely, for species linked to cereal and grassland-dominated landscapes, but not for landscape generalist species, distributed over mosaic landscapes including shrublands and woody crops. Results also highlight the importance of favourable extensive cereal steppes for the conservation of strongly endangered species (little and great bustard, Montagu’s harrier, pin-tailed sandgrouse, calandra lark), some of which are largely understudied (pin-tailed sandgrouse and calandra lark), despite their marginal coverage by the Natura 2000 protected area networkData analysed here come from a consultancy study “Revisión Fichas Red Natura 2000 aves esteparias Castilla–La Mancha” done by ELGM for the government of Castilla-La Mancha. contributes to project REMEDINAL TE-CM P2018/EMT-4338 of Comunidad de Madri

    Assessing vulnerability of functional diversity to species loss: a case study in Mediterranean agricultural systems

    Full text link
    "This is the peer reviewed version of the following article: Functional Ecology 31.2 (2017): 427-435, which has been published in final form at https://doi.org/10.1111/1365-2435.12709. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions"Increasing land-use intensification is leading to biodiversity losses world-wide, which can reduce the functioning of ecosystems. However, it is increasingly clear that not all species are equally important for ecosystem processes: whereas the loss of a functionally unique species may reduce the capacity of the community to perform some functions, losing a functionally redundant species should have a much smaller impact. Assessing the vulnerability of functional diversity (FD) to species extinctions can help to predict the impacts of land-use intensification. This approach consists in ranking species according to their risk of extinction and then estimating the trajectory followed by FD as species are lost from local communities. However, the most widely used FD indices are not independent of species richness, being much more sensitive to the loss of species in species-poor than in species-rich sites. This may result in misleading interpretations, affecting our ability to rank communities according to the vulnerability of their FD to species loss, by confounding it with the initial level of species richness. Here, we propose comparing the trajectory of FD under the most plausible order of species loss with that followed under random species losses as an effective way to remove the trivial effect of species richness in the assessments of vulnerability to species loss. After decoupling vulnerability from species richness, we used it to analyse the effect of agricultural intensification on the vulnerability of arable plant communities in Mediterranean agricultural fields. Our results show that management strategies aiming to increase the functionality of these systems should focus on intermediately intensified fields, where small reductions in the level of intensification are likely to benefit arable plant diversity, increasing the number of species and FD and decreasing the vulnerability of FD to species losses. Removing the effect of species richness is essential to attain unbiased estimations of the vulnerability of communities to species loss, especially when species-poor communities are considered. Combining vulnerability with information on taxonomic and functional diversity appears as a promising tool to inform decision-making processes, anticipating the effects of local extinction

    Agriculture intensification reduces plant taxonomic and functional diversity across European arable systems

    Full text link
    Los autores de la UAM pertenecen al Terrestrial Ecology Group (TEG)Agricultural intensification is one of the main drivers of species loss worldwide, but there is still a lack of information about its effect on functional diversity of arable weed communities. Using a large-scale pan European study including 786 fields within 261 farms from eight countries, we analysed differences in the taxonomic and functional diversity of arable weeds assemblages across different levels of agricultural intensification. We estimated weed species frequency in each field, and collected species' traits (vegetative height, SLA and seed mass) from the TRY plant trait database. With this information, we estimated taxonomic (species richness), functional composition (community weighted means) and functional diversity (functional richness, evenness, divergence and redundancy). We used indicators of agricultural management intensity at the individual field scale (e.g. yield, inputs of nitrogen fertilizer and herbicides, frequency of mechanical weed control practices) and at the landscape scale surrounding the field (i.e. number of crop types, mean field size and proportion of arable land cover within a radius of 500 m from the sampling points). The effects of agricultural intensification on species and functional richness at the field scale were stronger than those of intensification at the landscape scale, and we did not observe evidence of interacting effects between the two scales. Overall, assemblages in more intensified areas had fewer species, a higher prevalence of species with ruderal strategies (low stature, high leaf area, light seeds), and lower functional redundancy. Maintaining the diversity of Europe's arable weed communities requires some simple management interventions, for example, reducing the high intensity of field-level agricultural management across Europe, which could be complemented by interventions that increase landscape complexity. A free Plain Language Summary can be found within the Supporting Information of this articl

    Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

    Get PDF
    Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

    Ecología reproductiva y movimientos estacionales en la avutarda (Otis tarda)

    Get PDF
    El trabajo aborda tres aspectos fundamentales de la biología de la avutarda: los movimientos estacionales de los adultos, el éxito reproductor de las hembras tanto a escala poblacional, como individual, y el sistema de apareamiento. Este último se aborda bajo tres enfoques diferentes. Por una parte se describe la dinámica poblacional de la especie en el área de estudio durante la época de apareamiento. Por otro lado, se estudia la relación entre el fenotipo de los machos de avutarda y su comportamiento durante dicho periodo, así como la influencia de ambos en su capacidad para atraer hembras e incrementar, eventualmente, su éxito reproductor individual. Finalmente, se esplora, mediante un enfoque comparado, la relación entre dimorfismo sexual y sistema de apareamiento en el conjunto de la familia OTIDIDAE. La novedad de este estudio reside en su enfoque individual, basado en el seguimiento de avutardas capturadas por distintos procedimientos y marcadas mediante diversas técnicas con el fin de abordar en detalle los aspectos arriba mencionados.

    Assessing vulnerability of functional diversity to species loss: a case study in Mediterranean agricultural systems

    No full text
    "This is the peer reviewed version of the following article: Functional Ecology 31.2 (2017): 427-435, which has been published in final form at https://doi.org/10.1111/1365-2435.12709. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions"Increasing land-use intensification is leading to biodiversity losses world-wide, which can reduce the functioning of ecosystems. However, it is increasingly clear that not all species are equally important for ecosystem processes: whereas the loss of a functionally unique species may reduce the capacity of the community to perform some functions, losing a functionally redundant species should have a much smaller impact. Assessing the vulnerability of functional diversity (FD) to species extinctions can help to predict the impacts of land-use intensification. This approach consists in ranking species according to their risk of extinction and then estimating the trajectory followed by FD as species are lost from local communities. However, the most widely used FD indices are not independent of species richness, being much more sensitive to the loss of species in species-poor than in species-rich sites. This may result in misleading interpretations, affecting our ability to rank communities according to the vulnerability of their FD to species loss, by confounding it with the initial level of species richness. Here, we propose comparing the trajectory of FD under the most plausible order of species loss with that followed under random species losses as an effective way to remove the trivial effect of species richness in the assessments of vulnerability to species loss. After decoupling vulnerability from species richness, we used it to analyse the effect of agricultural intensification on the vulnerability of arable plant communities in Mediterranean agricultural fields. Our results show that management strategies aiming to increase the functionality of these systems should focus on intermediately intensified fields, where small reductions in the level of intensification are likely to benefit arable plant diversity, increasing the number of species and FD and decreasing the vulnerability of FD to species losses. Removing the effect of species richness is essential to attain unbiased estimations of the vulnerability of communities to species loss, especially when species-poor communities are considered. Combining vulnerability with information on taxonomic and functional diversity appears as a promising tool to inform decision-making processes, anticipating the effects of local extinction

    Population Genomics of Stone Age Eurasia

    No full text
    Summary The transitions from foraging to farming and later to pastoralism in Stone Age Eurasia (c. 11-3 thousand years before present, BP) represent some of the most dramatic lifestyle changes in human evolution. We sequenced 317 genomes of primarily Mesolithic and Neolithic individuals from across Eurasia combined with radiocarbon dates, stable isotope data, and pollen records. Genome imputation and co-analysis with previously published shotgun sequencing data resulted in >1600 complete ancient genome sequences offering fine-grained resolution into the Stone Age populations. We observe that: 1) Hunter-gatherer groups were more genetically diverse than previously known, and deeply divergent between western and eastern Eurasia. 2) We identify hitherto genetically undescribed hunter-gatherers from the Middle Don region that contributed ancestry to the later Yamnaya steppe pastoralists; 3) The genetic impact of the Neolithic transition was highly distinct, east and west of a boundary zone extending from the Black Sea to the Baltic. Large-scale shifts in genetic ancestry occurred to the west of this “Great Divide”, including an almost complete replacement of hunter-gatherers in Denmark, while no substantial ancestry shifts took place during the same period to the east. This difference is also reflected in genetic relatedness within the populations, decreasing substantially in the west but not in the east where it remained high until c. 4,000 BP; 4) The second major genetic transformation around 5,000 BP happened at a much faster pace with Steppe-related ancestry reaching most parts of Europe within 1,000-years. Local Neolithic farmers admixed with incoming pastoralists in eastern, western, and southern Europe whereas Scandinavia experienced another near-complete population replacement. Similar dramatic turnover-patterns are evident in western Siberia; 5) Extensive regional differences in the ancestry components involved in these early events remain visible to this day, even within countries. Neolithic farmer ancestry is highest in southern and eastern England while Steppe-related ancestry is highest in the Celtic populations of Scotland, Wales, and Cornwall (this research has been conducted using the UK Biobank resource); 6) Shifts in diet, lifestyle and environment introduced new selection pressures involving at least 21 genomic regions. Most such variants were not universally selected across populations but were only advantageous in particular ancestral backgrounds. Contrary to previous claims, we find that selection on the FADS regions, associated with fatty acid metabolism, began before the Neolithisation of Europe. Similarly, the lactase persistence allele started increasing in frequency before the expansion of Steppe-related groups into Europe and has continued to increase up to the present. Along the genetic cline separating Mesolithic hunter-gatherers from Neolithic farmers, we find significant correlations with trait associations related to skin disorders, diet and lifestyle and mental health status, suggesting marked phenotypic differences between these groups with very different lifestyles. This work provides new insights into major transformations in recent human evolution, elucidating the complex interplay between selection and admixture that shaped patterns of genetic variation in modern populations

    Population genomics of post-glacial western Eurasia

    No full text
    Western Eurasia witnessed several large-scale human migrations during the Holocene1,2,3,4,5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.info:eu-repo/semantics/publishedVersio

    Population genomics of post-glacial western Eurasia

    No full text
    : Western Eurasia witnessed several large-scale human migrations during the Holocene1-5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations
    corecore