The application of strongly oxidizing agents in flow injection analysis : Part 4. Manganese(VI) and Copper(III)

The application of manganese(VI) and copper(III) in strongly alkaline solutions as strong oxidizing reagents in flow injection analysis is described. Both reagents were prepared under batch conditions and fed to the flow from a stock solution. The reactions of most analytes tested with manganese(VI) required the use of a heated (65° C) reaction coil. The main application appears to be for the determination of monosaccharides in the 10−4–10−5 mol l−1 range

Stenoeciteit van de Nederlandse flora Een nieuwe parameter op grond van ecologische amplitudo's van de Nederlandse plantensoorten en toepassingsmogelijkheden

Er is een dBase gemaakt waarin op basis van expertkennis voor ruim 1750 Nederlandse plantensoorten ieder afzonderlijk op grond van de amplitudo’s van zeven milieuvariabelen (trofie, zuurgraad, zoutgehalte, vocht, bodemtextuur en bodemdynamiek en daglichttoestand) hun stenoeciteit berekend is. De uitkomst is gecheckt door de invoergegevens te vergelijken met actuele meetgegevens. De resultaten zijn gunstig, ook wat betreft de correlatie met plantensociologische data. Voor het eerst is de ecologie van de stadsplanten systematisch bepaald. Het blijkt dat onze floristische zorgenkinderen alle ecologisch zeer kieskeurig zijn. Het risico van uitsterven van soorten valt samen met een stenoeciteit van 26,5 en minder. Het wordt aanbevolen dit begrip ook voor andere groepen organismen toe te passen, waarvoor samenwerking met andere kennisdragers essentieel is. Door de bondigheid van de notie is het mogelijk om correlaties te onderzoeken met tal van data uit andere kennisdomeinen. Stenoeciteit kan ons in geografisch opzicht goed behulpzaam zijn om gebieden met relatief veel of weinig kieskeurige soorten aan te geven. Stenoeciteit past goed als maat én meetlat om bijvoorbeeld zowel nationaal als internationaal over gebiedskwaliteit te communiceren en bij realisatie van te verwachten nieuw EU-beleid voor GLB- of CAPmaatregelen (landbouw)

Normative Data for the Poreh Naming Test

The present study describes the development of a novel confrontational naming test for the assessment of word finding and language abilities, and also serves as a tool for the assessment of effort. The test is comprised of two portions. The first portion consists of 40 colored drawings of day to day objects and is aimed at assessing verbal abilities, particularly word finding deficits. The second portion also involves the presentation of 40 colored drawings, each drawing comprised of the original object that was previously presented and two distractors, objects that were not previously presented. The present study aims to evaluate the reliability and validity of this new measure in addition to providing preliminary normative data, and analyze the relationship between test performance and variables that have been shown to influence naming ability. The study shows that the new test might be useful for assessing both language abilities and effort

Normative Data for the Poreh Naming Test

The present study describes the development of a novel confrontational naming test for the assessment of word finding and language abilities, and also serves as a tool for the assessment of effort. The test is comprised of two portions. The first portion consists of 40 colored drawings of day to day objects and is aimed at assessing verbal abilities, particularly word finding deficits. The second portion also involves the presentation of 40 colored drawings, each drawing comprised of the original object that was previously presented and two distractors, objects that were not previously presented. The present study aims to evaluate the reliability and validity of this new measure in addition to providing preliminary normative data, and analyze the relationship between test performance and variables that have been shown to influence naming ability. The study shows that the new test might be useful for assessing both language abilities and effort

Onderzoek naar de ecologische achteruitgang en het herstel van Zuid-Limburgse hellingschraallandcomplexen

De Zuid-Limburgse hellingschraallanden behoren tot de meest soortenrijke graslandtypen in ons land. Ze liggen op een gradiënt van zure heischrale graslanden bovenaan de helling en basische kalkgraslanden in het middendeel van de helling. Onderaan de helling komen voedselrijkere en dus meer ruige graslandtypen voor. Het oppervlak aan goed ontwikkelde hellingschraallanden is in de 20e eeuw sterk achteruit gegaan en ook de kwaliteit ervan. Om na te gaan wat de oorzaken zijn voor de achteruitgang van flora als fauna en hoe verder herstelbeheer moet plaatsvinden, is in 2005 in het kader van OBN een vierjarig onderzoek gestart. Hieruit blijkt dat er zeker nog perspectief is voor herstel van soortenrijke hellingsschraallanden. Het beheer binnen de hellingschraallanden kan verder geoptimaliseerd worden, zodat meer afvoer van nutriënten plaatsvindt en een meer heterogene vegetatiestructuur ontstaat. Ook moet de sterke mate van versnippering en isolatie van de hellingschraallanden worden aangepakt door het vergroten en onderling verbinden van de huidige reservaten

Dispersal-mediated trophic interactions can generate apparent patterns of dispersal limitation in aquatic metacommunities

Dispersal is a major organising force in metacommunities, which may facilitate compositional responses of local communities to environmental change and affect ecosystem function. Organism groups differ widely in their dispersal abilities and their communities are therefore expected to have different adaptive abilities. In mesocosms, we studied the simultaneous compositional response of three plankton communities (zoo-, phyto- and bacterioplankton) to a primary productivity gradient and evaluated how this response was mediated by dispersal intensity. Dispersal enhanced responses in all three planktonic groups, which also affected ecosystem functioning. Yet, variation partitioning analyses indicated that responses in phytoplankton and bacterial communities were not only controlled by dispersal directly but also indirectly through complex trophic interactions. Our results indicate that metacommunity patterns emerging from dispersal can cascade through the food web and generate patterns of apparent dispersal limitation in organisms at other trophic levels.

Europees dagboek

Harrie Ozinga, derdejaars student Bestuurskunde, was samen met Martijn van den Heuvel, Barbara Bos, Marc Holtkamp en Vera Houtsma organisator van de buitenlandse excursie van de BIL. Van 26 september tot en met 1 oktober jongstleden werden in het kader van deze excursie Luxemburg, Straatsburg en Brussel aangedaan

Looking beyond the mountain: dispersal barriers in a changing world

0000-0001-7279-715X© The Ecological Society of America. The attached file is the published version of the article

Creation of micro-topographic features: a new tool for introducing specialist species of calcareous grassland to restored sites?

Questions: What types of pre-sowing disturbance are most suitable to establish specialist forbs of calcareous grassland at previously agriculturally improved restored sites? What impact does management regime have on post-establishment abundance-dynamics? Location: Pegsdon Hills, Bedfordshire, UK. Methods: We set up a 4-yr experiment using a split-plot design to combine pre-sowing disturbance treatments at sub-plot level (undisturbed control, glyphosate spraying, harrowing, and creation of ridge-and-furrow features) with three post-establishment management regimes applied at main plot level in years 2–4, involving either summer cutting or summer cattle grazing, and presence or absence of spring sheep grazing, along with autumn cattle grazing in all regimes. After disturbance application, we sowed a seed mixture containing ten specialist species of calcareous grassland. Using quadrat-based methods, we monitored first-year establishment and subsequent dynamics, including reproductive status of species at quadrat level. Initial establishment and subsequent dynamics were analysed separately using LMM. Results: Initial establishment of sown species was promoted both by harrowing and by ridge-and-furrow creation. While some species were about equally promoted by both, several other species benefited more strongly or exclusively from ridge-and-furrow creation. Effects of disturbance largely persisted in subsequent years, but for some species, different dynamics were observed for harrowed and ridge-and-furrow treatments. Thymus pulegioides and Hippocrepis comosa gradually achieved higher abundances in the ridge-and-furrow treatment, in which notable levels of bare ground persisted for much longer than in the harrowed treatment. In contrast, Filipendula vulgaris and Pimpinella saxifraga achieved higher abundance in the harrowed treatment. Sown species tended to reach reproductive stage faster in the ridge-and-furrow treatment than in the harrowed treatment. By the end of the study, management regimes had resulted in few effects on species dynamics. Conclusions: Establishment of specialist species of calcareous grassland crucially depended on bare ground creation prior to sowing. Ridge-and-furrow creation resulted in more persistent reduction of competition than the standard practice of harrowing, provided more suitable conditions for low-statured specialist species, and generally enabled faster transition of introduced specialist species to reproductive stage. Our results thus illustrate potential benefits of using more severe disturbance when introducing specialist species of calcareous grassland at restored sites