2,475 research outputs found
Reasons to Conserve Nature
Is it sufficient to base arguments for conservation on the intrinsic value of nature, regardless of the services and economic benefits that biodiversity provides for humans? This question underlies much recent debate that has been at times acrimonious and has led to calls for a more inclusive approach to conservation. Yet melding different ideologies within a unified conceptual framework has proven difficult. Here I describe an approach that recognizes the importance of the level of biological organization and spatial extent in determining the strength of alternative arguments for why we should conserve nature. I argue that the framework helps reconcile contrasting viewpoints and brings clarity to when different conservation management approaches (for instance, regulation versus monetary valuation) are most appropriate
Seasonal, annual and decadal change in tadpole populations in tropical Australian streams
Abstract Declines due to fungal disease (chytridiomycosis) have affected many stream-dwelling frog species, especially in the tropics, leading to reduced abundance and diversity of their tadpoles. Studies in the Australian Wet Tropics have demonstrated that some frog species have declined or disappeared, while others have persisted. To assess the occurrence of stream-breeding frogs, we monitored tadpole populations of five frog species in Wet Tropics streams in the early 1990s (uplands, before chytridomycosis emergence), and in 2011-2013 (uplands and lowlands, after chytridiomycosis emergence), and investigated environmental factors that might influence tadpole abundance. Riffle-dwelling tadpoles of two frog species disappeared from the upland stream site during the 1990s, reflecting reported losses of adult populations. Tadpoles of one upland pool species initially declined but had recovered by 2011-2013. Samples from the lowlands in 2011 to 2013 indicated no similar loss. Chytridiomycosis was the likely cause of changes in tadpole abundances between the two survey periods, given its known occurrence and documented effects on adult frogs in these systems; however, we did not measure its prevalence in this study. Tadpole populations fluctuated seasonally, with abundances highest in spring and summer, reflecting the timing of frog reproduction. The most important biophysical influence on the assemblages that we measured was current velocity. Tadpole peak abundances suggest that they make a substantial contribution at the consumer level of food webs, and that their loss has altered food webs substantially in upland streams.</jats:p
A null biogeographic test for assessing ecological niche evolution
AIMS: Quantification of the degree to which ecological niches change over evolutionary timescales is important for deepening our understanding of evolutionary and ecological processes.
Phylogenetic niche conservatism (PNC) is when closely related species differ less ecologically than expected by chance, whereas Phylogenetic Niche Divergence (PND) is when closely related species differ more ecologically than expected by chance. We present a new null model to test for PNC and PND (the RTR significance test), which we combine with a novel metric for quantifying niche overlap
LOCATION: Europe, North America and Madagascar.
METHODS: The RTR null model comprises many thousands of replicates generated by randomly translocating and rotating the set of occurrence records for two populations (e.g.,sister species) while maintaining the spatial configuration between all occurrences within each replicate. For each replicate we calculate niche overlap as the proportion of the combined niche breadth that is shared by the two species, averaged over n environmental dimensions.
This approach enables us to test whether the observed niche overlap is more or less than expected by chance given the environmental conditions present in the study area. We test the performance of our approach in comparison to other methods using both simulated and real case scenarios, including crested newts in Europe, pocket gophers in North America, and lemurs in Madagascar.
RESULTS: We find that our measure of niche overlap performs better than other metrics in an artificial simulation scenario, and we find evidence for both PNC and PND in our case studies for Europe, North America and Madagascar. Our results demonstrate that both the RTR significance test and the novel metric of niche overlap are consistent with evolutionary theory and are suitable methods to test for PNC and PND.
MAIN CONCLUSIONS:
We make available scripts to implement the RTR test and metric of niche overlap, and expect that the methods will prove useful for addressing a broad set of questions relating to ecological niche evolution and speciation, particularly for restricted-range species for which few known occurrence records are available
Rapid warming is associated with population decline among terrestrial birds and mammals globally.
Animal populations have undergone substantial declines in recent decades. These declines have occurred alongside rapid, human-driven environmental change, including climate warming. An association between population declines and environmental change is well established, yet there has been relatively little analysis of the importance of the rates of climate warming and its interaction with conversion to anthropogenic land use in causing population declines. Here we present a global assessment of the impact of rapid climate warming and anthropogenic land use conversion on 987 populations of 481 species of terrestrial birds and mammals since 1950. We collated spatially referenced population trends of at least 5 years' duration from the Living Planet database and used mixed effects models to assess the association of these trends with observed rates of climate warming, rates of conversion to anthropogenic land use, body mass, and protected area coverage. We found that declines in population abundance for both birds and mammals are greater in areas where mean temperature has increased more rapidly, and that this effect is more pronounced for birds. However, we do not find a strong effect of conversion to anthropogenic land use, body mass, or protected area coverage. Our results identify a link between rapid warming and population declines, thus supporting the notion that rapid climate warming is a global threat to biodiversity
Negative Biotic Interactions Drive Predictions of Distributions for Species From a Grassland Community
Understanding the factors that determine species’ geographic distributions is important for addressing a wide range of biological questions, including where species will be able to maintain populations following environmental change. New methods for modelling species distributions include the effects of biotic interactions alongside more commonly used abiotic variables such as temperature and precipitation; however, it is not clear which types of interspecific relationship contribute to shaping species distributions and should therefore be prioritised in models. Even if some interactions are known to be influential at local spatial scales, there is no guarantee they will have similar impacts at macroecological scales. Here we apply a novel method based on information theory to determine which types of interspecific relationship drive species distributions. Our results show that negative biotic interactions such as competition have the greatest effect on model predictions for species from a California grassland community. This knowledge will help focus data collection and improve model predictions for identifying at-risk species. Furthermore, our methodological approach is applicable to any kind of species distribution model that can be specified with and without interspecific relationships
Stability and aromaticity of nH2@B12N12 (n=1–12) clusters
Standard ab initio and density functional calculations are carried out to determine the structure, stability, and reactivity of B12N12 clusters with hydrogen doping. To lend additional support, conceptual DFT-based reactivity descriptors and the associated electronic structure principles are also used. Related cage aromaticity of this B12N12 and nH2@B12N12 are analyzed through the nucleus independent chemical shift values
Forecasting the combined effects of climate and land use change on Mexican bats
Aim: Climate and land use change are among the most important threatening processes driving biodiversity loss, especially in the tropics. Although the potential impacts of each threat have been widely studied in isolation, few studies have assessed the impacts of climate and land cover change in combination. Here, we evaluate the exposure of a large mammalian clade, bats, to multiple scenarios of environmental change and dispersal to understand potential consequences for biodiversity conservation. / Location: Mexico. / Methods: We used ensemble species distribution models to forecast changes in environmental suitability for 130 bat species that occur in Mexico by 2050s under four dispersal assumptions and four combined climate and land use change scenarios. We identified regions with the strongest projected impacts for each scenario and assessed the overlap across scenarios. / Results: The combined effects of climate and land use change will cause an average reduction in environmental suitability for 51% of the species across their range, regardless of scenario. Overall, species show a mean decrease in environmental suitability in at least 46% of their current range in all scenarios of change and dispersal. Climate scenarios had a higher impact on species environmental suitability than land use scenarios. There was a spatial overlap of 43% across the four environmental change scenarios for the regions projected to have the strongest impacts. / Main conclusions: Combined effects of future environmental change may result in substantial declines in environmental suitability for Mexican bats even under optimistic scenarios. This study highlights the vulnerability of megadiverse regions and an indicator taxon to human disturbance. The consideration of combined threats can make an important difference in how we react to changes to conserve our biodiversity as they pose different challenges
Predicting Distribution of Aedes Aegypti and Culex Pipiens Complex, Potential Vectors of Rift Valley Fever Virus in Relation to Disease Epidemics in East Africa.
The East African region has experienced several Rift Valley fever (RVF) outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. DIVERSE ECOLOGICAL NICHE MODELLING TECHNIQUES HAVE BEEN DEVELOPED FOR THIS PURPOSE: we present a maximum entropy (Maxent) approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex) responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods
From exercise intolerance to functional improvement: The second wind phenomenon in the identification of McArdle disease
McArdle disease is the most common of the glycogen storage diseases. Onset of symptoms is usually in childhood with muscle pain and restricted exercise capacity. Signs and symptoms are often ignored in children or put down to 'growing pains' and thus diagnosis is often delayed. Misdiagnosis is not uncommon because several other conditions such as muscular dystrophy and muscle channelopathies can manifest with similar symptoms. A simple exercise test performed in the clinic can however help to identify patients by revealing the second wind phenomenon which is pathognomonic of the condition. Here a patient is reported illustrating the value of using a simple 12 minute walk test.RSS is funded by Ciências sem Fronteiras/CAPES Foundation. The authors would like to thank the Association
for Glycogen Storage Disease (UK), the EUROMAC Registry funded by the European Union, the Muscular Dystrophy Campaign, the NHS National Specialist Commissioning Group and the Myositis Support Group for funding
The Performing Arts Data Service.
The Performing Arts Data Service (PADS), funded by the Joint Information
Systems Committee (JISC) and based at the University of Glasgow, aims to support research
and teaching in UK Higher Education by collecting and promoting the use of digital data
relating to the performing arts: music, film, broadcast arts, theatre and dance. The PADS is
one of 5 service providers of the Arts and Humanities Data Service (AHDS) which will
provide a single gateway for arts and humanities scholars wishing to search for datasets across
various discipline areas. Data is indexed with Dublin Core metadata, will interoperate with
other databases within the AHDS and beyond, and will be available via the Web
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