Stephen E. Williams

Bio: Stephen E. Williams is an academic researcher from James Cook University. The author has contributed to research in topics: Biodiversity & Climate change. The author has an hindex of 53, co-authored 126 publications receiving 25868 citations. Previous affiliations of Stephen E. Williams include International Union for Conservation of Nature and Natural Resources & Cooperative Research Centre.

On the isolated population of Lewin’s Honeyeater (Meliphaga lewinii amphochlora) from the McIlwraith Range uplands, Cape York Peninsula, Australia: estimates of population size and distribution

Abstract: Subspecies amphochlora of the Lewin’s Honeyeater (Meliphaga lewinii) is confined to a small isolated population in the McIlwraith Range, Cape York Peninsula, north-eastern Australia The population is poorly known but is thought to be restricted to elevations above 500 m We aimed to establish reliable estimates of population size and geographical range to enable a better evaluation of the conservation status of the subspecies We also sought to quantify elevational patterns of density within the range and test the hypothesis that climate is the dominant factor governing range limits We estimate the area of occupancy to be 183 km2, pending the investigation of three small fragments of predicted suitable habitat in mountain ranges to the north of the McIlwraith Range Our count data indicate that the population probably consists of fewer than 5000 individuals (best estimate = 4666 individuals, 95% confidence intervals (CI) = 2868–7591) Highest densities were observed in a geographically limited subset of the range above 650 m Independent validation of our species-climate distribution model suggests that the restricted spatial distribution of the subspecies is attributable to climate associations and implies that warm temperatures in particular act to restrict the lower elevational limit of the subspecies We discuss the implications of these findings for the future survival of M l amphochlora in the context of contemporary climate warming

Gap Analysis of Environmental Research Needs in the Australian Wet Tropics

Abstract: Environmental research involves "understanding how environmental systems function and interact, and the impact that humans are having on the environment". Strengthened linkages between terrestrial biodiversity researchers and end-users are desirable to reduce duplicative effort and achieve maximum return on public investment in applied research. To assist this process, our analysis provides a significant review and consultation process with the aim of identifying end‐user needs, research gaps and possible synergies, delivering a valuable resource for terrestrially focussed research providers and end-user groups. This report provides a resource for research providers by helping to locate relevant research information more efficiently, and by ensuring that proposed research is strategic and targeted at the needs of the end‐users. It provides a resource for end-users by delivering a repository of biodiversity research that is digested and easily accessible, and by identifying the areas of research where stakeholder interests overlap. Finally, the report can also be used by funding bodies to help guide the prioritisation of resources into future biodiversity research in the Wet Tropics bioregion.

Impacts of global climate change on the rainforest vertebrates of the Australian Wet Tropics

Abstract: Climate change is a particularly significant threat to the long-term preservation of the biota in the tropical rainforests of Australia's Wet Tropics World Heritage Area. The Wet Tropics is dominated by mountain ranges with altitudes varying sharply between sea level and over 1600 m. Environmental gradients associated with a complex topography dominate the biogeography of the region (Nix and Switzer 1991, Williams et al. 1996). The gradient in altitude is the most significant environmental gradient determining species composition and general patterns of biodiversity (Williams et al. 1996, Williams and Pearson 1997). Most rainforest is above 300 m and almost all of the regionally endemic species are cool-adapted upland species (Nix and Switzer 1991, Williams et al. 1996).

Measuring and monitoring wildlife communities : the problem of bias

Abstract: The sustainable use of any natural resource ideally requires a baseline measurement of the biodiversity of the system, followed by consistent monitoring of the resource and other elements of the ecosystem which might possibly be affected by the utilisation of the resource. If it is necessary to monitor a faunal community (or biodiversity) rather than a single species, the number of biases involved in measuring or monitoring community parameters are greatly increased. Monitoring the relative abundance of the different species in a faunal assemblage necessitates an understanding of the associated sampling biases. These biases vary greatly between species, habitats, seasons, weather conditions, sampling technique and observers. Methods of adjusting for these types of biases are discussed using as an example the mammal assemblages of tropical rainforest in north Queensland.

Historical environmental stability drives discordant niche filling dynamics across phylogenetic scales

Abstract: Aim: Regional diversity can increase owing to either the packing of species within regional niche space or the expansion of regional niche space. Yet, the primary factors dictating these dynamics remain poorly understood. Here, we assess the relative influence of current environmental conditions (net primary productivity, NPP) versus historic environmental stability over the Last Glacial Maximum on niche filling patterns of vertebrates (mammals, birds, amphibians and reptiles) in the Australian Wet Tropics (AWTs). Location: Australian Wet Tropics. Taxon: Vertebrates (mammals, birds, amphibians and reptiles). Methods: We measured patterns of niche filling (niche packing vs. niche expansion) as the standardized departure of observed functional diversity (FD) from its null expectation. We fitted spatial models for vertebrates, and for each constituent class (mammals, birds, amphibians and reptiles) separately, to evaluate the relative effects of NPP and environmental stability on species richness and niche filling patterns. Results: Historical environmental stability had a greater effect than NPP on species richness and niche filling patterns. However, the directionality of this effect depended on phylogenetic scale, with vertebrates exhibiting niche packing while each constituent class (except reptiles) exhibited niche expansion with increasing environmental stability. Main Conclusion: Intra-class competition presumably leads to niche differentiation and expansion, whereas the overlap of functional traits among species from different classes leads to niche packing. That environmental stability over millennia is associated with an expanding niche space across multiple vertebrate classes suggests that the accumulation of FD within communities requires long recovery times.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.