Richard D. Bardgett

Bio: Richard D. Bardgett is an academic researcher from University of Manchester. The author has contributed to research in topics: Ecosystem & Soil biology. The author has an hindex of 115, co-authored 381 publications receiving 51685 citations. Previous affiliations of Richard D. Bardgett include Lancaster University & English Nature.

Urban and agricultural soils: conflicts and trade-offs in the optimization of ecosystem services

Abstract: On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.

Effect of density and species richness of soil mesofauna on nutrient mineralisation and plant growth

Abstract: The aim of this study was to test the relative importance of changes in density and species richness of soil mesofauna as determinants of nutrient mineralisation and plant growth The experiment was carried out using microcosms containing a mixture of plant litter and soil in which seedlings of Lolium perenne were planted, and a range of combinations of levels of density and species richness of microarthropods added Over the duration of the experiment, nutrient release, measured as concentrations of NO3--N and total N in leachates, increased significantly with increasing microarthropod density, but decreased with increasing species richness Leachate concentrations of NH4+-N, dissolved organic N and C (DON and DOC) were not affected by the faunal treatments Soil respiration, a measure of microbial activity, decreased with increasing density of microarthropods, whereas microbial biomass was not affected by microarthropods Increasing density of soil animals had a negative effect on the shoot biomass of L perenne while the effect of species richness was positive Neither the species richness nor density of soil microarthropods was found to significantly influence root biomass We conclude that variations in animal density had a greater influence on soil nutrient mineralisation processes than did species richness Possible reasons for these opposing effects of animal density and diversity on soil N mobilization are discussed

Long-term aboveground and belowground consequences of red wood ant exclusion in boreal forest

Abstract: Despite their ubiquity, the role of ants in driving ecosystem processes both aboveground and belowground has been seldom explored, except within the nest. During 1995 we established 16 ant exclusion plots of approximately 1.1 x 1.1 m, together with paired control plots, in the understory layer of a boreal forest ecosystem in northern Sweden that supports high densities of the mound-forming ant Formica aquilonia, a red wood ant species of the Formica rufa group. Aboveground and belowground measurements were then made on destructively sampled subplots in 2001 and 2008, i.e., 6 and 13 years after set-up. While ant exclusion had no effect on total understory plant biomass, it did greatly increase the relative contribution of herbaceous species, most likely through preventing ants from removing their seeds. This in turn led to higher quality resources entering the belowground subsystem, which in turn stimulated soil microbial biomass and activity and the rates of loss of mass and carbon (C) and nitrogen (N) from litter in litterbags placed in the plots. This was accompanied by losses of approximately 15% of N and C stored in the humus on a per area basis. Ant exclusion also had some effects on foliar stable isotope ratios for both C and N, most probably as a consequence of greater soil fertility. Further, exclusion of ants had multitrophic effects on a microbe-nematode soil food web with three consumer trophic levels and after six years promoted the bacterial-based relative to the fungal-based energy channel in this food web. Our results point to a major role of red wood ants in determining forest floor vegetation and thereby exerting wide-ranging effects on belowground properties and processes. Given that the boreal forest occupies 11% of the Earth's terrestrial surface and stores more C than any other forest biome, our results suggest that this role of ants could potentially be of widespread significance for biogeochemical nutrient cycling, soil nutrient capital, and sequestration of belowground carbon.

Inter-specific variability in organic nitrogen uptake of three temperate grassland species.

Abstract: We tested the inter-specific variability in the ability of three dominant grasses of temperate grasslands to take up organic nitrogen (N) in the form of amino acids in soils of differing fertility. Amino acid uptake was determined by injecting dual labeled glycine-2-C-13-N-15 into the soil, and then measuring the enrichment of both C-13 and N-15 in plant tissue after 50 hours. We found enrichment of both C-13 and N-15 in root and shoot material of all species in both soils, providing first evidence for direct uptake of glycine. We show that there was considerable inter-specific variability in amino acid uptake in the low fertility soil. Here, direct uptake of amino acid was greater in the grass Agrostis capillaris, which typically dominates low fertility grassland, than Lolium perenne, which inhabits more fertile sites. Direct uptake of amino acid for Holcus lanatus was intermediate between the above two species. Unlike in the low fertility soil, there was no difference in uptake of either C-13 or N-15 by grasses in the high fertility soil, where uptake of mineral N is thought to be the major mechanism of N uptake of these grasses. Overall, our findings may contribute to our understanding of differences in competitive interactions between grasses in soils of different fertility status.

The effect of transgenic nematode resistance on non-target organisms in the potato rhizosphere

Abstract: 1. Plant-parasitic nematodes are important pests of agriculture and transgenic plants with potential for nematode control are currently being developed. The expression of cysteine proteinase inhibitors (cystatins) in potato confers partial resistance to potato-cyst nematode (PCN). Here, we used field studies to test for effects of cystatin-expressing potato on non-target soil organisms. 2. Microbial community structure, soil microarthropods and litter decomposition were studied during two growing seasons. In the second year, nematode control options of cystatin-expressing plants and an oxime carbamate nematicide application were compared for their non-target effects. 3. In the first year, the transgenic lines had no effect on the abundance, evenness or metabolic activity of the soil microbial community as determined by ester-linked phospholipid fatty acid analysis (PLFA). However, one transgenic line (D6/7) influenced the structure of the soil microbial community. PLFA suggested it favoured fungal growth relative to bacterial growth during the latter parts of the growing season. A second transgenic line (D5/13) was more effective against PCN. It reduced the abundance of the fungal fatty acid 18:2omega6 in late season, suggesting a suppression of fungal growth. 4. In the second year PLFA analysis suggested microbial abundance was reduced by 15% and 23% in the nematicide and transgenic treatments, respectively, relative to the control. Nematicidal treatment reduced the bacterial fraction of the microbial community, whereas the transgenic plants suppressed both the bacterial and fungal community components. 5. The observed changes in soil microbial community structure did not result in changes in the rate of leaf litter decomposition. 6. The transgenic lines had no significant effect on the abundance of soil microarthropods or free-living nematodes. 7. The study is the first stage of a risk assessment of the impact of transgenic nematode resistance on non-target soil organisms. It has highlighted the importance of including currently used management options when studying the effect of transgenic plants on non-target organisms. Both nematicide use and the transgenic plants affected components of the soil microbial community. However, the changes brought about by the two treatments were not sufficient to affect soil functioning, as measured by rates of litter decomposition.

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。

Effects of biodiversity on ecosystem functioning: a consensus of current knowledge

Abstract: Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls. The scientific community has come to a broad consensus on many aspects of the re- lationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are struc- tured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.

Modern Applied Statistics With S

Abstract: Thank you very much for downloading modern applied statistics with s. As you may know, people have search hundreds times for their favorite readings like this modern applied statistics with s, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. modern applied statistics with s is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the modern applied statistics with s is universally compatible with any devices to read.

Biodiversity loss and its impact on humanity

Abstract: The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world's nations declared that human actions were dismantling the Earth's ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.

Climate Change 2007: The Physical Science Basis.

Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.