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4,156 result(s) for "Green, R. E."
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Global mapping of ecosystem services and conservation priorities
Global efforts to conserve biodiversity have the potential to deliver economic benefits to people (i.e., \"ecosystem services\"). However, regions for which conservation benefits both biodiversity and ecosystem services cannot be identified unless ecosystem services can be quantified and valued and their areas of production mapped. Here we review the theory, data, and analyses needed to produce such maps and find that data availability allows us to quantify imperfect global proxies for only four ecosystem services. Using this incomplete set as an illustration, we compare ecosystem service maps with the global distributions of conventional targets for biodiversity conservation. Our preliminary results show that regions selected to maximize biodiversity provide no more ecosystem services than regions chosen randomly. Furthermore, spatial concordance among different services, and between ecosystem services and established conservation priorities, varies widely. Despite this lack of general concordance, \"win-win\" areas--regions important for both ecosystem services and biodiversity--can be usefully identified, both among ecoregions and at finer scales within them. An ambitious interdisciplinary research effort is needed to move beyond these preliminary and illustrative analyses to fully assess synergies and trade-offs in conserving biodiversity and ecosystem services.
Agricultural intensification and the collapse of Europe's farmland bird populations
The populations of farmland birds in Europe declined markedly during the last quarter of the 20th century, representing a severe threat to biodiversity. Here, we assess whether declines in the populations and ranges of farmland birds across Europe reflect differences in agricultural intensity, which arise largely through differences in political history. Population and range changes were modelled in terms of a number of indices of agricultural intensity. Population declines and range contractions were significantly greater in countries with more intensive agriculture, and significantly higher in the European Union (EU) than in former communist countries. Cereal yield alone explained over 30% of the variation in population trends. The results suggest that recent trends in agriculture have had deleterious and measurable effects on bird populations on a continental scale. We predict that the introduction of EU agricultural policies into former communist countries hoping to accede to the EU in the near future will result in significant declines in the important bird populations there.
Monitoring change in biodiversity through composite indices
The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points-points at which the underlying trend changes-be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.
MAGEMin, an Efficient Gibbs Energy Minimizer: Application to Igneous Systems
Prediction of stable mineral equilibria in the Earth's lithosphere is critical to unravel the tectonomagmatic history of exposed geological sections. While the recent advances in geodynamic modeling allow us to explore the dynamics of magmatic transfer in solid mediums, there is to date no available thermodynamic package that can easily be linked and efficiently be accounted for the computation of phase equilibrium in magmatic systems. Moreover, none of the existing tools fully exploit single point calculation parallelization, which strongly hinders their applicability for direct geodynamic coupling or for thermodynamic database inversions. Here, we present a new Mineral Assemblage Gibbs Energy Minimizer (magemin). The package is written as a parallel C library, provides a direct Julia interface, and is callable from any petrological/geodynamic tool. For a given set of pressure, temperature, and bulk‐rock composition magemin uses a combination of linear programming, extended Partitioning Gibbs Energy and gradient‐based local minimization to compute the stable mineral assemblage. We apply our new minimization package to the igneous thermodynamic data set of Holland et al. (2018), https://doi.org/10.1093/petrology/egy048 and produce several phase diagrams at supra‐solidus conditions. The phase diagrams are then directly benchmarked against thermocalc and exhibit very good agreement. The high scalability of magemin on parallel computing facilities opens new horizons, for example, for modeling reactive magma flow, for thermodynamic data set inversion, and for petrological/geophysical applications. Plain Language Summary Understanding magmatic systems requires knowing how rocks melt. Because a single melting experiment can easily take weeks, it is impossible to do enough experiments to cover the whole range of pressure, temperature, and composition relevant for magmatic systems. We therefore need a way to interpolate in between conditions that are not directly covered by the experiments. It is long known that the best way to perform such interpolation is by using basic thermodynamic principles. For magmatic systems, this requires a well‐calibrated thermodynamic melting model. It also requires an efficient computational tool to predict the most stable configuration of minerals and melt. Since the 1980s, a number of such computational tools have been developed to perform a so‐called Gibbs energy minimization. These tools work very well for simpler systems but become very slow for recently developed, more realistic, melting models. Here, we describe a new method that combines some ideas of the previous methods with a new algorithm. Our method is faster and takes advantage of modern computer architectures. It can predict rock properties such as densities, seismic velocities, melt content, and chemistry. It can therefore be used to link physical observations with hard rock data of magmatic systems. Key Points A new, parallel, Gibbs energy minimization approach is presented to compute multiphase multicomponent equilibria It predicts parameters like stable phases, melt content, or seismic velocities as a function of chemistry and temperature/pressure conditions Examples and benchmark cases are presented that apply the approach to magmatic systems
Patterns of Nucleotide Misincorporations during Enzymatic Amplification and Direct Large-scale Sequencing of Ancient DNA
Whereas evolutionary inferences derived from present-day DNA sequences are by necessity indirect, ancient DNA sequences provide a direct view of past genetic variants. However, base lesions that accumulate in DNA over time may cause nucleotide misincorporations when ancient DNA sequences are replicated. By repeated amplifications of mitochondrial DNA sequences from a large number of ancient wolf remains, we show that C/G-to-T/A transitions are the predominant type of such misincorporations. Using a massively parallel sequencing method that allows large numbers of single DNA strands to be sequenced, we show that modifications of C, as well as to a lesser extent of G, residues cause such misincorporations. Experiments where oligonucleotides containing modified bases are used as templates in amplification reactions suggest that both of these types of misincorporations can be caused by deamination of the template bases. New DNA sequencing methods in conjunction with knowledge of misincorporation processes have now, in principle, opened the way for the determination of complete genomes from organisms that became extinct during and after the last glaciation.
Complete Mitochondrial Genomes of Ancient Canids Suggest a European Origin of Domestic Dogs
The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.
An Experimental Study of the Effects of Predation on the Breeding Productivity of Capercaillie and Black Grouse
1. The capercaillie Tetrao urogallus and black grouse Tetrao tetrix are declining in the UK, and low breeding success has been identified as the key factor in the decline of the former. To investigate possible causes, breeding productivity was studied in relation to predation, weather, vegetation changes and deer numbers over an 11-year period (1989-99) within native pinewood at Abernethy Forest, Scotland. The abundance of predators (crows Corvus corone and red foxes Vulpes vulpes) was experimentally manipulated in 1992-96 by culling. Productivity (chicks reared per female) was compared between forests with and without experimental predator management. 2. During predator control, the number of breeding crows was reduced from 10 pairs to one. The attempted reduction in red fox abundance was unsuccessful; only small numbers of adults were killed, and neither scat nor den counts declined significantly. 3. Predation on artificial nests containing six hen eggs and a hen egg filled with wax was measured as an index of predator activity from 1991 to 1999. Predation was lowest during the last three years of predator control, 1994-96. Predators could sometimes be distinguished by signs on depredated eggs. Predation on artificial nests by crows was highest during 1991-93. However, after predator removal stopped in 1997 few crows returned, and increased predation on artificial nests did not involve increased signs of crow predation. Pine marten Martes martes numbers increased during the study period and became significant predators of artificial nests. 4. The total number of capercaillie eggs and nests depredated by crows was estimated from the number of depredated capercaillie eggs found and the proportion of crow-predated hen eggs in artificial nests. The values ranged from 18 to 158 eggs over 3 years, equivalent to 3-23 capercaillie nests year-1. 5. Capercaillie productivity was low (< 1 chick per female) during 1989-93 and 1997-99 but higher during 1994-96. Compared with nine other forests in Scotland, changes in capercaillie productivity at Abernethy were different. Productivity at Abernethy was negatively related to June rainfall, and to the minimum daily predation rate on artificial nests by crows. There was also a significant interaction in that capercaillie were most productive when low rainfall coincided with low predation by crows on artificial nests. 6. The productivities of black grouse and capercaillie were positively correlated, but greater in the former. As in capercaillie, black grouse productivity was negatively related both to June rainfall and the minimum daily predation rate on artificial nests by crows, and there was an interaction. 7. Synthesis and applications. The long-term increase in crows and red foxes and the predicted increase in rainfall in Scotland may have negative effects on capercaillie and black grouse. In the short term, control of crows is likely to improve productivity. In the long term, increased woodland size and some reversal of fragmentation might decrease the access to woodland of predators associated with the interface between farmland and woodland.
The Influence of Numbers Released on the Outcome of Attempts to Introduce Exotic Bird Species to New Zealand
1. Information on the approximate number of individuals released is available for 47 of the 133 exotic bird species introduced to New Zealand in the late 19th and early 20th centuries. Of these, 21 species had populations surviving in the wild in 1969-79. The long interval between introduction and assessment of outcome provides a rare opportunity to examine the factors correlated with successful establishment without the uncertainty of long-term population persistence associated with studies of short duration. 2. The probability of successful establishment was strongly influenced by the number of individuals released during the main period of introductions. Eight-three per cent of species that had more than 100 individuals released within a 10-year period became established, compared with 21% of species that had less than 100 birds released. The relationship between the probability of establishment and number of birds released was similar to that found in a previous study of introductions of exotic birds to Australia. 3. It was possible to look for a within-family influence on the success of introduction of the number of birds released in nine bird families. A positive influence was found within seven families and no effect in two families. This preponderance of families with a positive effect was statistically significant. 4. A significant effect of body weight on the probability of successful establishment was found, and negative effects of clutch size and latitude of origin. However, the statistical significance of these effects varied according to whether comparison was or was not restricted to within-family variation. After applying the Bonferroni adjustment to significance levels, to allow for the large number of variables and factors being considered, only the effect of the number of birds released was statistically significant. 5. No significant effects on the probability of successful establishment were apparent for the mean date of release, the minimum number of years in which birds were released, the hemisphere of origin (northern or southern) and the size and diversity of latitudinal distribution of the natural geographical range.
Two New Eimeria Species Parasitic in Corncrakes (Crex crex) (Gruiformes: Rallidae) in the United Kingdom
In this study we describe 2 new species of coccidia (Apicomplexa: Eimeriidae) parasites isolated from the feces of corncrake (Crex crex) (Gruiformes: Rallidae), bred in captivity in the U.K. Oocysts of Eimeria crecis n. sp. were approximately spherical and measured 15.3 μm (13–18) × 14.3 (12–16), providing an oocyst shape index of 1.1. A micropyle and oocyst residuum were absent, but a polar granule was present. Oocysts of Eimeria nenei n. sp. were ellipsoidal and measured 23.6 (21–26) × 18.1 (17–20), providing an oocyst shape index of 1.3. A micropyle and polar granule were present. Surveying free-living, wild adult corncrakes in Scotland (U.K.) demonstrated both parasite species to be widespread. These are the first species described to infect the corncrake, and they are distinct from those previously found to infect members of the closely related crane family (Gruiformes: Gruidae). Partial amplification and sequencing of the 18S rRNA gene and internal transcribed spacer 2 indicated a close relationship between the 2 proposed new species as a group distinct from the Eimeria species known to infect cranes. These newly identified parasite species have been associated with enteric disease in corncrakes being prepared for reproduction in captivity and reintroduction into England (U.K.).