Taxonomic and functional diversity of farmland bird communities across Europe:Effects of biogeography and agricultural intensification

In eight European study sites (in Spain, Ireland, Netherlands, Germany, Poland, Estonia and Sweden), abundance of breeding farmland bird territories was obtained from 500 × 500 m survey plots (30 per area, N = 240) using the mapping method. Two analyses were performed: (I) a Canonical Correspondence Analysis of species abundance in relation to geographical location and variables measuring agricultural intensification at field and farm level to identify significant intensification variables and to estimate the fractions of total variance in bird abundance explained by geography and agricultural intensification; (II) several taxonomic and functional community indices were built and analysed using GLM in relation to the intensification variables found significant in the CCA. The geographical location of study sites alone explains nearly one fifth (19. 5%) of total variation in species abundance. The fraction of variance explained by agricultural intensification alone is much smaller (4. 3%), although significant. The intersection explains nearly two fifths (37. 8%) of variance in species abundance. Community indices are negatively affected by correlates of intensification like farm size and yield, whereas correlates of habitat availability and quality have positive effects on taxonomic and functional diversity of assemblages. Most of the purely geographical variation in farmland bird assemblage composition is associated to Mediterranean steppe species, reflecting the bio-geographical singularity of that assemblage and reinforcing the need to preserve this community. Taxonomic and functional diversity of farmland bird communities are negatively affected by agricultural intensification and positively affected by increasing farmland habitat availability and quality. © 2011 Springer Science+Business Media B.V.

Geochemical records of palaeoenvironmental controls on peat forming processes in the Mfabeni peatland, Kwazulu Natal, South Africa since the Late Pleistocene

The Mfabeni peatland is the only known sub-tropical coastal fen that transcends the Last Glacial Maximum (LGM). This ca. 10m thick peat sequence provides a continuous sedimentation record spanning from the late Pleistocene to present (basal age c. 47kcalyr BP). We investigated the paleaeoenvironmental controls on peat formation and organic matter source input at the Mfabeni fen by: 1) exploring geochemical records (mass accumulation rate, total organic carbon, carbon accumulation rate, δC, δN and C/N ratio) to delineate primary production, organic matter source input, preservation and diagenetic processes, and 2) employ these geochemical signatures to reconstruct the palaeoenvironmental conditions and prevailing climate that drove carbon accumulation in the peatland. We established that the Mfabeni peat sediments have undergone minimal diagenetic alteration. The peat sequence was divided into 5 linear sedimentation rate (LSR) stages indicating distinct changes in climate and hydrological conditions: LSR stage 1 (c. 47 to c. 32.2kcalyr BP): predominantly cool and wet climate with C4 plant assemblages, interrupted by two short warming events. LSR stage 2 (c. 32.2 to c. 27.6kcalyr BP): dry and windy climate followed by a brief warm and wet period with increased C4 sedge swamp vegetation. LSR stage 3 (c. 27.6 to c. 20.3kcalyr BP): initial cool and wet period with prevailing C4 sedge plant assemblage until c. 23kcalyr BP; then an abrupt change to dry and cool glacial conditions and steady increases in C3 grasses. LSR stage 4 (c. 20.3 to c. 10.4kcalyr BP): continuation of cool and dry conditions and strong C3 grassland signature until c. 15kcalyr BP, after which precipitation increases. LSR stage 5 (c. 10.4kcalyr BP to present): characterised by extreme fluctuations between pervasive wet and warm to cool interglacial conditions with intermittent abrupt millennial-scale cooling/drying events and oscillations between C3 and C4 plant assemblages. In this study we reconstructed a high-resolution record of local hydrology, bulk plant assemblage and inferred climate since the Late Pleistocene, which suggest an anti-phase link between Southern African and the Northern Hemisphere, most notably during Heinrich (5 to 2) and Younger Dryas events. © 2013 Elsevier B.V.

Flexural behaviour of external R/C steel fibre reinforced beam-column joints

A softened strut-and-tie macro model able to reproduce the flexural behaviour of
external beam-column joint is presented. The model is specific for concrete with hooked steel fibres (FRC) and it is designed to calculate the flexural response, as load-deflection curve, of a beam-column sub-assemblages. The model considers the presence of a constant vertical load acting on the column and of a monotonically increasing lateral force applied at the tip of the beam.

Comportamento flessionale di nodi esterni in calcestruzzo fibrorinforzato

SOMMARIO – Si presenta un macro modello di tipo reticolare in grado di riprodurre il comportamento in presenza di taglio e momento di nodi esterni trave-colonna di telai in calcestruzzo fibrorinforzato con fibre di acciaio
uncinato ed ordinario. Il caricamento del sistema è di tipo monotono come nel caso dell’analisi di pushover. Il modello considera la presenza di armature orizzontali e verticali della regione nodale e tiene in conto delle modalità
di rottura legate allo snervamento delle barre e allo schiacciamento delle regioni compresse in regime di sforzi pluriassiali. Il modello include le deformazioni flessionali della trave e della colonna in presenza di sforzo normale costante e restituisce la risposta del sistema colonna-nodo-trave (sub-assembralggio) tramite le curve carico-freccia all’estremità della semitrave. Per i singoli costituenti (trave, colonna e nodo) si è considerata la prima fessurazione, lo snervamento e lo schiacciamento delle regioni compresse e si sono fornite precise indicazioni sulla sequenza degli eventi che come è noto sono di fondamentale importanza per lo sviluppo di un progetto plastico che rispetti la gerarchia delle resistenze. Con l’uso del modello il controllo della gerarchia delle resistenze avviene a livello sezionale (lo snervamento delle barre deve avvenire prima dello schiacciamento delle regioni compresse) o di macro elemento (nella regione nodale lo snervamento delle staffe precede la crisi dei puntoni) e dell’intero elemento
sub-assemblaggio trave debole, colonna forte e nodo sovraresistente.
La risposta ottenuta con i modello proposto è in buon accordo con le risposte sperimentali disponibili in letteratura (almeno in termini di resistenza del sub-assemblaggio). Il modello è stato ulteriormente validato con analisi
numeriche agli elementi finiti condotte con il codice ATENA-2D. Le analisi numeriche sono state condotte utilizzando per il calcestruzzo fibroso adeguate leggi costitutive proposte dagli autori ed in grado di cogliere gli effetti
di softening e di resistenza residua a trazione legati alla presenza di fibre. Ulteriori sviluppi del modello saranno indirizzati a includere gli effetti di sfilamento delle barre d’armatura della trave e del conseguente degrado delle
tensioni d’aderenza per effetto di carichi monotonici e ciclici.

SUMMARY – A softened strut-and-tie macro model able to reproduce the flexural behavior of external beam-tocolumn joints with the presence of horizontal and vertical steel bars, including softening of compressed struts and yielding of main and secondary steel bars, is presented, to be used for the pushover analysis. The model proposed is able to calculate also the flexural response of fibrous reinforced concrete (FRC) beam-to-column sub-assemblages in term of a multilinear load-deflection curves. The model is able to take into account of the tensile behavior of main bars embedded in the surrounding concrete and of the softening of the compressed strut, the arrangement and percentage of the steel bars, the percentage and the geometry of steel fibers. First cracking, yielding of main steel and crushing of concrete were identified to determine the corresponding loads and displacement and to plot the simplified monotonic load-deflection curves of the sub-assemblages subjected in the column to constant vertical
load and at the tip of the beam to monotonically increasing lateral force. Through these load-delfection curves the component (beam, joint and column) that first collapse can be recognized and the capacity design can be verified.
The experimental results available in the literature are compared with the results obtained through the proposed model. Further, a validation of the proposed model is numerically made by using a non linear finite element program (ATENA-2D) able to analyze the flexural behavior of sub-assemblages.

Autoecological Approaches to Resolve Subjective Taxonomic Divisions within Arcellacea

Arcellacea (testate lobose amoebae) are important lacustrine environmental indicators that have been used in paleoclimatic reconstructions, assessing the effectiveness of mine tailings pond reclamation projects and for studying the effects of land use change in rural, industrial and urban settings. Recognition of ecophenotypically significant infra-specific ‘strains’ within arcellacean assemblages has the potential to enhance the utility of the group in characterizing contemporary and paleoenvironments. We present a novel approach which employs statistical tools to investigate the environmental and taxonomic significance of proposed strains. We test this approach on two identified strains: Difflugia protaeiformis Lamarck strain ‘acuminata’ (DPA), characterized by fine grained agglutination, and Difflugia protaeiformis Lamarck strain ‘claviformis’ (DPC), characterized by coarse grained agglutination. Redundancy analysis indicated that both organisms are associated with similar environmental variables. No relationship was observed between substrate particle size and abundance of DPC, indicating that DPC has a size preference for xenosomes during test construction. Thus DPC should not be designated as a distinct strain but rather form a species complex with DPA. This study elucidates the need to justify the designation of strains based on their autecology in addition to morphological stability.

Magma Evolution in the Primitive, Intra-oceanic Tonga Arc: Petrogenesis of Basaltic Andesites at Tofua Volcano

Tofua volcano is situated midway along the Tonga oceanic arc and has undergone two phases of ignimbrite-forming activity. The eruptive products are almost entirely basaltic andesites (52 center dot 5-57 wt % SiO2) with the exception of a volumetrically minor pre-caldera dacite. The suite displays a strong tholeiitic trend with K2O <1 wt %. Phenocryst assemblages typically comprise plagioclase + clinopyroxene +/- orthopyroxene with microlites of Ti-magnetite. Olivine (Fo(83-88)) is rare and believed to be dominantly antecrystic. An increase in the extent and frequency of reverse zoning in phenocrysts, sieve-textured plagioclase and the occurrence of antecrystic phases in post-caldera lavas record a shift to dynamic conditions, allowing the interaction of magma batches that were previously distinct. Pyroxene thermobarometry suggests crystallization at 950-1200 degrees C and 0 center dot 8-1 center dot 8 kbar. Volatile measurements of glassy melt inclusions indicate a maximum H2O content of 4 center dot 16 wt % H2O, and CO2-H2O saturation curves indicate that crystallization occurred at two levels, at depths of 4-5 center dot 5 km and 1 center dot 5-2 center dot 5 km. Major and trace element models suggest that the compositions of the majority of the samples represent a differentiation trend whereby the dacite was produced by 65% fractional crystallization of the most primitive basaltic andesite. Trace element models suggest that the sub-arc mantle source is the residuum of depleted Indian mid-ocean ridge basalt mantle (IDMM-1% melt), whereas radiogenic isotope data imply addition of 0 center dot 2% average Tongan sediment melt and a fluid component derived from the subducted altered Pacific oceanic crust. A horizontal array on the U-Th equiline diagram and Ra excesses of up to 500% suggest fluid addition to the mantle wedge within the last few thousand years. Time-integrated (Ra-226/Th-230) vs Sr/Th and Ba/Th fractionation models imply differentiation timescales of up to 4500 years for the dacitic magma compositions at Tofua.

Palynological perspectives on vegetation survey: a critical step for model-based reconstruction of Quaternary land cover

1. Quantitative reconstruction of past vegetation distribution and abundance from sedimentary pollen records provides an important baseline for understanding long term ecosystem dynamics and for the calibration of earth system process models such as regional-scale climate models, widely used to predict future environmental change. Most current approaches assume that the amount of pollen produced by each vegetation type, usually expressed as a relative pollen productivity term, is constant in space and time.
2. Estimates of relative pollen productivity can be extracted from extended R-value analysis (Parsons and Prentice, 1981) using comparisons between pollen assemblages deposited into sedimentary contexts, such as moss polsters, and measurements of the present day vegetation cover around the sampled location. Vegetation survey method has been shown to have a profound effect on estimates of model parameters (Bunting and Hjelle, 2010), therefore a standard method is an essential pre-requisite for testing some of the key assumptions of pollen-based reconstruction of past vegetation; such as the assumption that relative pollen productivity is effectively constant in space and time within a region or biome.
3. This paper systematically reviews the assumptions and methodology underlying current models of pollen dispersal and deposition, and thereby identifies the key characteristics of an effective vegetation survey method for estimating relative pollen productivity in a range of landscape contexts.
4. It then presents the methodology used in a current research project, developed during a practitioner workshop. The method selected is pragmatic, designed to be replicable by different research groups, usable in a wide range of habitats, and requiring minimum effort to collect adequate data for model calibration rather than representing some ideal or required approach. Using this common methodology will allow project members to collect multiple measurements of relative pollen productivity for major plant taxa from several northern European locations in order to test the assumption of uniformity of these values within the climatic range of the main taxa recorded in pollen records from the region.

Carvel Chair

A chair made using traditional boatbuilding techniques, which shape timber into incredibly strong and light shell forms. Made with wind felled larch, copper roves and rivets, steel bar

Investigation of Aircraft Panel Deformations during Riveting Process

In collaboration with Airbus-UK, the dimensional growth of small panels while being riveted with stiffeners is investigated. The stiffeners have been fastened to the panels with rivets and it has been observed that during this operation the panels expand in the longitudinal and transverse directions. It has been observed that the growth is variable and the challenge is to control the riveting process to minimize this variability. In this investigation, the assembly of the small panels and longitudinal stiffeners has been simulated using low and high fidelity nonlinear finite element models. The models have been validated against a limited set of experimental measurements; it was found that more accurate predictions of the riveting process are achieved using high fidelity explicit finite element models. Furthermore, through a series of numerical simulations and probabilistic analyses, the manufacturing process control parameters that influence panel growth have been identified. Alternative fastening approaches were examined and it was found that dimensional growth can be controlled by changing the design of the dies used for forming the rivets.

Community structure, diversity and spatial organization of enchytraeids in Mediterranean urban holm oak stands

There is a strong northern bias in Europe as regards enchytraeid community ecology, particularly in urban settings. We approached the enchytraeid assemblages of urban holm oak stands in Naples and Siena adopting a high intensity sampling that, for the first time in the Mediterranean climate zone, would ensure that the data collected be representative of the target populations. Structural parameters (diversity and evenness, biomass, size classes, aggregation) were compared across different spatial (regional, urban district, within habitat) and temporal scales (season and year). Species richness was found to change significantly only at regional scale; background data suggest that this may depend on the higher environmental heterogeneity occurring at Naples. Differences in size class structure were significant only on a seasonal scale and within either city separately. With one exception (Fridericia bulbosa s.s.), the patterns of spatial aggregation of the common species were fairly robust and the total range of patchiness was consistent with previous studies, despite the different sampling methodologies. The size of the sampling unit, the number of replicates per plot and the number of plots proposed in this study appear suitable to obviate the difficulties of evaluating Mediterranean enchytraeid communities.

Disturbance, neutral theory and patterns of beta diversity in soil communities

Beta diversity describes how local communities within an area or region differ in species composition/abundance. There have been attempts to use changes in beta diversity as a biotic indicator of disturbance, but lack of theory and methodological caveats have hampered progress. We here propose that the neutral theory of biodiversity plus the definition of beta diversity as the total variance of a community matrix provide a suitable, novel, starting point for ecological applications. Observed levels of beta diversity (BD) can be compared to neutral predictions with three possible outcomes: Observed BD equals neutral prediction or is larger (divergence) or smaller (convergence) than the neutral prediction. Disturbance might lead to either divergence or convergence, depending on type and strength. We here apply these ideas to datasets collected on oribatid mites (a key, very diverse soil taxon) under several regimes of disturbances. When disturbance is expected to increase the heterogeneity of soil spatial properties or the sampling strategy encompassed a range of diverging environmental conditions, we observed diverging assemblages. On the contrary, we observed patterns consistent with neutrality when disturbance could determine homogenization of soil properties in space or the sampling strategy encompassed fairly homogeneous areas. With our method, spatial and temporal changes in beta diversity can be directly and easily monitored to detect significant changes in community dynamics, although the method itself cannot inform on underlying mechanisms. However, human-driven disturbances and the spatial scales at which they operate are usually known. In this case, our approach allows the formulation of testable predictions in terms of expected changes in beta diversity, thereby offering a promising monitoring tool.

Consistent effects of consumer species loss across different habitats

Our knowledge of the effects of consumer species loss on ecosystem functioning is limited by a paucity of manipulative field studies, particularly those that incorporate inter-trophic effects. Further, given the ongoing transformation of natural habitats by anthropogenic activities, studies should assess the relative importance of biodiversity for ecosystem processes across different environmental contexts by including multiple habitat types. We tested the context-dependency of the effects of consumer species loss by conducting a 15-month field experiment in two habitats (mussel beds and rock pools) on a temperate rocky shore, focussing on the responses of algal assemblages following the single and combined removals of key gastropod grazers (Patella vulgata, P. ulyssiponensis, Littorina littorea and Gibbula umbilicalis). In both habitats, the removal of limpets resulted in a larger increase in macroalgal richness than that of either L. littorea or G. umbilicalis. Further, by the end of the study, macroalgal cover and richness were greater following the removal of multiple grazer species compared to single species removals. Despite substantial differences in physical properties and the structure of benthic assemblages between mussel beds and rock pools, the effects of grazer loss on macroalgal cover, richness, evenness and assemblage structure were remarkably consistent across both habitats. There was, however, a transient habitat-dependent effect of grazer removal on macroalgal assemblage structure that emerged after three months, which was replaced by non-interactive effects of grazer removal and habitat after 15 months. This study shows that the effects of the loss of key consumers may transcend large abiotic and biotic differences between habitats in rocky intertidal systems. While it is clear that consumer diversity is a primary driver of ecosystem functioning, determining its relative importance across multiple contexts is necessary to understand the consequences of consumer species loss against a background of environmental change.

Laboratizing the border: The production, translation and anticipation of security technologies

This paper critically interrogates how borders are produced by scientists, engineers and security experts in advance of the actual deployment of technical devices they develop. This paper explores the prior stages of translation and decision-making as a socio-technical device is conceived and developed. Drawing on in-depth interviews, observations and ethnographic research of the EU-funded Handhold project (consisting of nine teams in five countries), it explores how assumptions about the way security technologies will and should perform at the border shape the way that scientists, engineers, and security experts develop a portable, integrated device to detect CBRNE threats at borders. In disaggregating the moments of sovereign decision making across multiple sites and times, this paper questions the supposed linearity of how science comes out of and feeds back into the world of border security. An interrogation of competing assumptions and understandings of security threats and needs, of competing logics of innovation and pragmatism, of the demands of differentiated temporalities in detection and interrogation, and of the presumed capacities, behaviours, and needs of phantasmic competitors and end-users reveals a complex, circulating and co-constitutive process of device development that laboratises the border itself. We trace how sovereign decisions are enacted as assemblages in the antecedent register of device development itself through the everyday decisions of researchers in the laboratory, and the material components of the Handhold device itself.

Effects of baited crab pots on cultivated mussel (Mytilus edulis) survival rates

The shore crab, Carcinus maenas, is recognized as a voracious predator of blue mussels, Mytilus edulis, having the potential to greatly reduce stocks in the benthic cultivation industry. As a consequence, baited crab pots are often deployed on and around cultivated benthic mussel beds to trap and remove crabs, in an attempt to reduce predatory pressure. Little is known about how C. maenas behaves around crab pots, but for many other crustacean fisheries, the trapping efficiency of pots is often low. Crabs may be attracted towards but not enter pots, instead feeding on cultivated mussels outside pots on the surrounding substratum. We tested whether the rate of loss of mussels attached to plates differed in areas next to baited pots compared with unbaited pots and to areas without any pots, at two sea loughs (60 km apart) in Northern Ireland. In Strangford Lough, more mussels were lost from plates next to baited pots than the other treatments. In Carlingford Lough, however, we found no difference in the number of mussels lost from plates in any treatment. This difference could be attributed to the different assemblages of mobile benthic predators at the two loughs. The presence of the starfish Asterias rubens, which was absent from experimental sites in Carlingford Lough, was thought to be responsible for increased predation rates near baited pots in Strangford. It is, therefore, important to consider local predator communities when deploying crab pots as a predator mitigation technique to ensure predation rates are in fact reduced and not enhanced. This study is of relevance not only to attempts to limit predation on commercial stocks of benthic cultivated mussels but also in situations where baited traps are deployed close to species vulnerable to mobile benthic predators.

Inland shell midden site-formation:Investigation into a late Pleistocene to early Holocene midden from Trang An, Northern Vietnam

Over the course of the past two decades there has been growing research interest in the site formation processes of shell middens. This stands along-side and is being used to inform cultural, dietary and palaeo-environmental reconstructions. Just as midden site formation processes have turned out to be many and varied, however, the kinds of shell-bearing sites that past human communities created are likely to have been no less diverse. Subsuming such sites under a single category - shell middens - normalises that variation and may lead to the misinterpretation of site function. The greater part of research in this field also continues to focus on coastal shell middens; comparatively little attention has been paid to middens containing freshwater and especially terrestrial molluscs from hinterland locations. As a result, much of the current understanding about shell-midden sites carries a spatial as well as a functional bias. This paper hopes to contribute towards discussion on both fronts. It presents a detailed examination of the formation processes that went into the creation of a land snail-dominated late- to post-glacial midden from northern Vietnam, and considers the role that it may have played in the early settlement of this area. The data presented comes from ongoing archaeological excavations at Hang Boi, a cave located in the sub-coastal karstic uplands of Trang An park, in the Vietnamese Province of Ninh Binh. (C) 2010 Elsevier Ltd and INQUA. All rights reserved.