Risk maps summarizing landscape suitability of novel areas for invading species can be valuable tools for preventing species’ invasions or controlling their spread, but methods employed for ...development of such maps remain variable and unstandardized. We discuss several considerations in development of such models, including types of distributional information that should be used, the nature of explanatory variables that should be incorporated, and caveats regarding model testing and evaluation. We highlight that, in the case of invasive species, such distributional predictions should aim to derive the best hypothesis of the potential distribution of the species by using (1) all distributional information available, including information from both the native range and other invaded regions; (2) predictors linked as directly as is feasible to the physiological requirements of the species; and (3) modelling procedures that carefully avoid overfitting to the training data. Finally, model testing and evaluation should focus on well-predicted presences, and less on efficient prediction of absences; a k-fold regional cross-validation test is discussed.
Aim
Correlative species distribution models (SDMs) are subject to substantial spatio‐temporal limitations when historical occurrence records of data‐poor species provide incomplete and outdated ...information for niche modelling. Complementary mechanistic modelling techniques can, therefore, offer a valuable contribution to underpin more physiologically informed predictions of biological invasions, the risk of which is often exacerbated by climate change. In this study we integrate physiological and human pressure data to address the uncertainties and limitations of correlative SDMs and to better understand, predict and manage biological invasions.
Location
Western archipelagos of the Southern Ocean and martime Antarctica.
Taxon
Eretmoptera murphyi (Chironomidae), invertebrates.
Methods
Mahalanobis Distances were used for correlative SDM construction for a species with few records. A mechanistic SDM was built around different fitness components (larval survival and life stage progression) as a function of temperature. SDM predictions were combined with human activity levels in Antarctica to generate a site vulnerability index to the assess colonization risk of E. murphyi. Future scenarios of ecophysiological suitability were built around the warming trends in the region.
Results
Both SDMs converge to predict high environmental suitability in the species' native and introduced ranges. However, the mechanistic model indicates a slightly larger invasive potential based on larval performance at different temperatures. Human activity levels across the Antarctic Peninsula play a key role in discerning site vulnerabilities. Niche suitability in Antarctica grows considerably under long‐term climate scenarios, leading to a substantially higher invasive threat to the Antarctic ecosystems. In turn changing conditions result in growing physiological mismatches with the environment in the native range in South Georgia.
Main conclusions
Long‐term studies of invasion potential under climate benefit from integrating correlative predictions with physiological experiments, as the invasion potential varies depending on the area and the timescale examined. This study also highlights a conservation paradox whereby the accidental introduction of an insect represents a threat to the Antarctic ecoystems that contrasts with its endangered status at the native range.
The Iberian Peninsula is a major European region of biodiversity, as it harbours more than 30% of European endemic species. Despite a number of studies having evaluated the ability of nature reserves ...to protect certain taxa, there is still a lack of knowledge on how Iberian endemic fauna are represented in these reserves. We detected biodiversity hotspots of Iberian endemicity and evaluated the effectiveness of the Natura 2000 network (N2000) in representing 249 endemic species from eight animal taxonomic groups (amphibians, mammals, freshwater fishes, reptiles, water beetles, butterflies, lacewings and dung beetles). We found that only the 10% of these Iberian endemic species are considered species of community interest (i.e. species included in the Annexes of the Habitats Directive). We conducted gap analyses and null models of representativeness in N2000. Generally, N2000 is effective in its representation of Iberian endemic fauna, although we detected species and few hotspots of endemism that were still not represented. It is necessary to declare a few new protected areas, thus enhancing N2000's effectiveness in the conservation of the Iberian endemic fauna. Although the aim of N2000 is to protect species listed in the Birds and Habitats Directives, the conservation status of endemic species from one of the most important areas of Europe in terms of biodiversity, could be also a concern for the European Union. Our results are useful in the context of the recent European Commission mandate calling for a ‘fitness check’ of the Birds and Habitats Directives. This approach could be also applicable to other regions with high value of endemicity.
The Iberian Peninsula harbours more than 30% of European endemic species, however there is still a lack of knowledge on how Iberian endemic fauna are represented in nature reserves. We detected biodiversity hotspots of Iberian endemicity and evaluated the effectiveness of the Natura 2000 network (N2000) in representing 249 endemic species from eight animal taxonomic groups. In general, N2000 is effective in its representation of Iberian endemic fauna, although we detected species and a few hotspots of endemism that were not represented. The obtained results are useful in the context of the recent European Commission mandate calling for a ‘fitness check’ of the Birds and Habitats Directives, being also applicable to other regions with high value of endemicity.
Climate change can induce shifts in species ranges. Of special interest are range shifts in regions with a conflict of interest between land use and the conservation of threatened species. Here we ...focus on the 94 threatened terrestrial vertebrates occurring in the Madrid region (Central Spain) and model their distributions using data for the whole peninsular Spain to evaluate which vertebrate groups are likely to be more sensitive to climatic change. First, we generated predictive models to quantify the extent to which species distributions are explained by current climate. We then extrapolated the models temporally to predict the effects of two climate-change scenarios on species distributions. We also examined the impact on a recently proposed reserve relative to other interconnected zones with lower protection status but categorized as Areas of Community Importance by the European Union. The variation explained by climatic predictors was greater in ectotherms. The change in species composition differed between the proposed reserve and the other protected areas. Endothermic and ectothermic vertebrates had different patterns of changes in species composition but those of ectotherms matched with temperature departures predicted by climate change. Our results, together with the limited dispersal capacity of herptiles, suggest that trade-offs between different design criteria accounting for animal group differences are necessary for reserve selection.
For millennia, locust swarms have recurrently devastated crop productivity across continents. In much of Europe, locust outbreaks have been considerably reduced by human pressure in recent decades, ...but important foci of outbreaks still exist in Spain. Distribution models are often used to derive spatial hypotheses and risk maps. Because insufficient information is available to include the extreme plasticity of the solitary and gregarious phases of locusts in large‐scale spatial models, we modelled the distribution either of Acrididae species or of outbreaks per se. Confirmed occurrences of Dociostaurus, Calliptamus and Chorthippus species were obtained from a field survey complemented by museum collection data and the published literature. The locations of confirmed or potential outbreaks covering two time periods of 20 years each were obtained from the literature and from Spanish autonomous community reports. Models were built with one topographic and eleven climatic predictors. We evaluated the ability of different models to predict outbreak recurrence and found that models based on Moroccan locust data or outbreak occurrence data performed the best. We generated a predictive map of the climatic favourability for locust outbreaks in Spain and found that the major foci of locust swarms were encompassed by those areas categorized by the models as areas of highest risk. Predictive maps of outbreak favourability can facilitate the more sustainable use of insecticides and more efficient integrated pest management.
1. Individuals following different strategies such as philopatry or dispersal may also differ in other phenotypic traits, since dispersing individuals have to face novel physical and social ...environments. There is growing evidence of the use of information obtained from conspecifics in a variety of contexts. It has been demonstrated that before natal dispersal, juveniles of Lacerta vivipara use social information through conspecific chemical cues, and that various phenotypes use this information differently. We hypothesized that, after dispersal, the behavioural responses of yearlings to different social environments assessed through conspecific odours depend on the dispersal status. 2. We tested the response of philopatric and dispersing yearlings of L. vivipara to different types of social cues, controlling for the prenatal and postnatal environment. Each yearling was faced with environments with no conspecific odours, with scent-marks from one or three yearlings that were held isolated during captivity, and from three socially housed yearlings. Thus, we examined the response to the number of donors and to the social environment experienced by donors. We recorded the time spent walking and attempting to escape as indicators of activity and avoidance response, respectively. 3. Philopatric and dispersing individuals reacted differently to the social environments presented through odour marks. This dispersal status-dependent response was not modulated by the prenatal and postnatal factors examined.
Abstract Parkinson's disease is a chronic, debilitating, progressive neurological disorder of multifactorial origin. It affects between 0.3% and 2% of the over-65 population worldwide, with a ...predilection for men, and is characterised by bradykinesia, muscular rigidity, resting tremor and postural instability. Parkinson's is caused by decreased dopamine levels due to the loss of dopaminergic neurons in the substantia nigra. Because dopamine is a highly oxidisable molecule, precursors such as levodopa, together with catechol-O-methyltransferase and monoamine oxidase inhibitors to prevent degradation, are used in the treatment of this disease. These therapies, however, are not without their adverse effects. Surgical treatments for Parkinson's include pallidotomy, therapy deep brain stimulation, and stem cells. A more recent development involves a titanium dioxide micro-implant containing nanopores that stabilise the dopamine for continuous release. When inserted into the caudate nucleus, this micro-implant was found to counteract 85% of symptoms in hemiparkinsonian rats, and is a promising therapy for patients with Parkinson's disease.
Accident Tolerant Fuels, also known as Advanced Technology Fuels (ATFs), have the potential to improve the safety and economic performance of commercial nuclear reactors as well as to provide ...additional operational flexibility for responding to variations in system energy demand.
The design, fabrication and in-pile behaviour of currently operating and innovative nuclear fuels to enable a reliable and safe operation of nuclear power plants is a priority for the nuclear industry. The Spanish nuclear professionals (public and private companies, academia, and research centres) have achieved significant advances in this area. Both irradiation programs in commercial reactors, along with experimental and modelling activities, were focused into comprehending and modelling different ATF concepts to understand and predict the behaviour under normal and off-normal conditions.
The International Atomic Energy Agency (IAEA) sub-program “Nuclear Power Reactor Fuel Engineering” is strongly involved in the development and validation of computer codes for ATF fuel design and the valuable Spanish contribution to this sub-program is described in this article.
The future Spanish R&D in this field is expected to be focused on further improvements on ATF product development and performance knowledge.
Genetic, biochemical and structural studies have implicated Argonaute proteins as the catalytic core of the RNAi effector complex, RISC. Here we show that recombinant, human Argonaute2 can combine ...with a small interfering RNA (siRNA) to form minimal RISC that accurately cleaves substrate RNAs. Recombinant RISC shows many of the properties of RISC purified from human or Drosophila melanogaster cells but also has surprising features. It shows no stimulation by ATP, suggesting that factors promoting product release are missing from the recombinant enzyme. The active site is made up of a unique Asp-Asp-His (DDH) motif. In the RISC reconstitution system, the siRNA 5' phosphate is important for the stability and the fidelity of the complex but is not essential for the creation of an active enzyme. These studies demonstrate that Argonaute proteins catalyze mRNA cleavage within RISC and provide a source of recombinant enzyme for detailed biochemical studies of the RNAi effector complex.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
PDF
