Search publications of the members of the Royal Belgian institute of natural Sciences
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Towards a better knowledge and protection of biodiversity in Africa using Web 2.0 technologies
- For more than 10 years, thanks to funding provided by the Belgian Development Cooperation (DGD), the Belgian Clearing House Mechanism (CHM) team of the Convention on Biological Diversity (CBD), has been helping its partner countries in the South develop their national CHM networks. In 2003, the European Union adopted the PTK (Portal Toolkit): a Content Management System that allows to develop national CHM websites in Europe. The PTK is released under the Mozilla Public License. It is a free and open source software, that allows multi user-generated content. It includes collaborative tools managed through the Web, such as discussion forums, consultations and surveys. With the PTK, users can: • Mobilize networks of experts through a user-friendly content management system • Raise public awareness by uploading short films, photos and presentations • Communicate biodiversity by state-of-the-art mapping services using YAHOO backgrounds and Google Earth exports • Prepare for biodiversity reporting by using public content contribution, user discussion forum, public consultation tools, survey tools and syndication • Collaborate in technical and scientific projects with modern web standards • Connect biodiversity databases. Belgium has been using the PTK for its national CHM website (http://www.biodiv.be/) for 10 years. More than 30 countries in Africa use the PTK for their national websites (such as Benin, Madagascar, Morocco, etc.), see full list here (http://www.biodiv.be/cooperation/chm_coop/chm-partnering/part_country). The national website URLs are as follows: country code + .chm-cbd.net. For instance, for Niger, the URL is http://ne.chm-cbd.net. The Belgian CHM hosts the national CHM websites of its partner countries on its server and offers training courses for the development and maintenance of these websites. Distance learning manuals on the use of the PTK have been developed by the Belgian CHM team for the last 4 years. The manuals are developed both in English and French. They are available on a training website: http://training.biodiv.be/formationptk. This website is used for distance learning for our partners and for any other interested party but also for blended learning. Two weeks before a face-to-face training in a partner country, all future trainees are invited to: • surf their national CHM website; • read a basic manual that introduces the PTK and the CHM; • create a user account on the training website.
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What is inside this pit? Micro- and macrofaunal investigations at Chalcolithic and Early Bronze Age Ovçular Tepesi (Nakhchivan, Azerbaijan )
- The site of Ovçular Tepesi is located in the southern Caucasus (Nakhchivan Autonomous Republic). Two main archaeological phases were recognised at the settlement, namely Late Chalcolithic and Early Bronze Age. More than 1160 litres of soil samples from pits and circular stone structures belonging to the different occupation layers were processed by flotation and analysed. This paper focuses on the zoological finds from these samples, in particular the remains of fish, large mammals and micromammals, in order to determine the function of the pits and structures. Moreover, the material gives an insight into the animal economy, hunting and fishing practices of the inhabitants, as well as the local environment. Thus far, it could not be established whether the differences detected in the species composition between the phases are related to chronology alone or if other factors, such as sample sizes and type of deposits, also played a role. Fish bones were very frequent at the site with cyprinids dominating. Among the large mammals, domestic animals were the most frequent while hunted species were rare. Sheep and goat herding seems to have been the principal subsistence strategy at this site. The small mammal community is composed of synanthropic taxa and, as a consequence, the species diversity was very low (six taxa). House mouse was the most abundant in each feature on the site.
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Keihard bedreigd erfgoed – de kassei : de geschiedenis van onze steden met de voeten getreden
- SAMENVATTING. Het verlies aan kassei-patrimonium in België en Nederland is schrijnend zowel in historische stadscen- tra en op plattelandswegen als op erven of binnenpleinen van private gebouwen. Bij de herinrichting van autoluwe stadsker- nen wordt een vernieuwde belangstelling opgemerkt voor het gebruik van kasseien, maar hier worden eerder importstenen gebruikt, actueel voornamelijk van Aziatische oorsprong. De essentiële kwaliteiten van kasseien zijn de lage impact op het milieu als natuurproduct tijdens de hele levensduur en hun inbreng in de opwaardering van het stedelijk gebouwde patrimo- nium. Historische Belgische straatstenen zijn erg divers van samenstelling en eigenschappen, en bezitten een unieke en onver- vangbare geodiversiteitswaarde. Vervanging door gestandaardiseerde importsteen draagt zo bij tot de banalisering van de openbare ruimtes. Er is nood aan praktische handleidingen voor het materiaalgebruik en de uitvoeringswijze van kasseibestra- tingen in onze historische centra. Dit wordt duidelijk aangetoond door de huidige en in deze publicatie beschreven situatie van de stadscentra van Brussel, Ciney, Leuven en Gent in België én door de gevalstudie van het Marktplein van Geertruidenberg, één van de oudste natuurstenen bestratingen van Nederland, die tot op de dag van vandaag dreigt te verdwijnen en uitgevoerd te worden in andere materialen. Uit het geheel wordt een algemene nood bemerkt aan sensibilisering bij de burger alsook de overheden van het feit dat authenticiteit een prijs heeft en tegengesteld is aan vlakheid en soms ook aan gebruiksgemak. ABSTRACT. The loss of cobblestone pavements in historical city centres, on traditional roads in the countryside, on farmyards and inner courts of private buildings deprives the built heritage in Belgium and the Netherlands of its hori- zontal dimension. Although there is a renewed interest in cobblestones for the renovation of city centres, most often, imported stones are used, especially of Asian origin. The principal qualities of cobblestones as a natural product are their low environmental impact during their entire life cycle and their positive contribution to the overall quality of the built heritage. Historic Belgian cobblestones have very diverse compositions and characteristics, and they possess unique and irreplaceable geodiversity values. Replacement by standardized imported stone contributes to the trivialization of public places. There is a need for practical guidelines to describe the materials to be used and to specify how to use the material for traditional cobblestone pavements. The urgency is demonstrated in this paper by case studies from the city centres of Brussels, Ciney, Louvain and Ghent in Belgium and of the market place of Geertruidenberg. The latter is one of the oldest natural stone pavements of the Netherlands, which is threatened to be lost and to be replaced by other materials. In particular, there is a need to raise public awareness and to raise awareness of the authorities stressing the fact that authen- ticity has a certain price and that this may be contradictory to commonplace and to user demand.
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Diestiaan ijzerzandsteen: de erfgoedsteen van het Hageland
- SAMENVATTING. Een donkerbruine, ijzerhoudende zandsteen tekent het landschap en de karakteristieke archi- tectuur van het Hageland, het oostelijk deel van de provincie Vlaams-Brabant. Deze regio wordt gekenmerkt door een heuvelachtig landschap, waar in Romeinse tijden op de zuidelijk gerichte flanken al wijn werd verbouwd. Op de talrijke heuveltoppen, stille getuigen van versteende zandbanken in de Laat-Miocene zee die het landschap in lang vervlogen tijden overspoelde, komen donkerbruine lagen van ijzerzandsteen voor. Al sinds de vroege Middeleeuwen werd deze steen voor lokaal gebruik ontgonnen, waaruit later de voor de streek typische ‘Demergotiek’ ontstond. De ijzerzandsteen is zeer heterogeen en gevoelig voor verwering. Over het algemeen betreft het een bouwmateriaal met een lage druksterkte, zeker in vergelijking met Gobertange, Lede- of Doornikse steen. De hedendaagse restauratie van deze karakteristieke architectuur wordt geconfronteerd met diverse problemen: natuursteenherstelling is omwille van de donkere kleur minder evident en vaak niet duurzaam, beschikbare reserves zijn zeer beperkt en er zijn geen actieve steengroeves. Een maximale conservering van het authentieke materiaal, geheel in overeenkomst met het Charter van Venetië overigens, dient daarom vaak vooropgesteld. Materiaaltechnisch onderzoek van ijzerzandsteen, gelicht uit gesteentelagen in vijf sites, was noodzakelijk om de wisselende kenmerken van deze natuursteen beter te interpreteren vanuit zijn geologische diversiteit, teneinde de inzetbaarheid als bouwmateriaal te kunnen evalueren. Bovendien werd bestudeerd in hoeverre een mogelijke steen- verstevigende behandeling door middel van ethylsilicaat (TEOS) van ijzerzandsteen tot een verbetering van zijn duur- zaamheid zou kunnen leiden. ABSTRACT. Diest ferruginous sandstone, heritage stone of the Hageland. A dark-brown ferruginous sandstone characterizes the landscape and the typical architecture of the Hageland, the eastern part of the Belgian province Flemish Brabant. The landscape of this region is recognised by an alternation of hills. The southern flanks of these hills are well-suited for cultivating wine, something the Romans already learned some two thousand years ago. On these numerous hill tops, the silent witnesses of petrified shoals from the Diestian sea which overran the landscape long ago, dark-brown layers of ferruginous sandstone occur. Already in the Middle Ages, this stone has been quarried for local use which gradually led to the development of a specific architecture, also known as Demer Gothic. This ferruginous sandstone is however very heterogeneous and sensitive to weathering. In general, it is considered a rather weak building material, especially in comparison with other typical local building materials such as Gobertange, Lede or Tournais stones. However, the restoration of this characteristic architecture is nowadays confronted with various problems: the use of repair mortars is because of the dark color less evident and often not durable, available reserves are restricted and there are actually no active quarries. A maximal conservation of the authentic material, fully in agreement with the Charter of Venice, is hence often required as a premise. Material-technical research of fer- ruginous sandstone, retrieved from sedimentary beds from five locations, was deemed necessary to describe the vary- ing characteristics of this stone within its geological context in order to evaluate the possibility to use the material for restoration purposes. In addition, the effect of a consolidation treatment of the ferruginous sandstone with ethylsilicate (TEOS) to ameliorate its durability was examined.
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Natuursteengebruik als urbanisatie-indicator stadskern Leuven
- SAMENVATTING. Natuursteen is een duurzaam element in de bouwgeschiedenis en als zodanig een goede indicator voor bouwjaar, stijl en mogelijke renovatie. Natuursteengebruik wordt doorgaans geanalyseerd vanuit typologie, scha- depathologie, marktpenetratie of geografische verspreiding. Hieruit kunnen trends worden gehaald over aanwending en waardering. Informatie over de globale impact van natuursteengebruik in het straatbeeld, daarin inbegrepen de ver- naculaire woningbouw, ontbreekt. Om hieraan tegemoet te komen werd een systematische inventarisatie uitgevoerd van het natuursteengebruik in gevels van gebouwen gelegen binnen een historische stadskern. De Leuvense binnen- stad leende zich uitstekend voor dit onderzoek omdat er vrijwel continu is gebouwd gedurende de 19de en 20ste eeuw, zonder uitgesproken dominante stijlen of materialen. Kwalitatieve kenmerken zoals natuursteengebruik, bouwjaar en –stijl werden ingevoerd in een GIS bestand zodat de evolutie van het materiaalgebruik kan worden gekoppeld aan de voortschrijdende verstedelijking. Dit laat tevens toe pijnpunten inzake conservering of verwaarlozing vast te stellen. SUMMARY. Natural stone use as an indicator for urbanisation of the historical city centre of Leuven (Louvain). The use of natural stone for building follows trends depending on changes in availability and appreciation, but is generally analysed in selected historical buildings for specific issues such as typology, market penetration, geographi- cal distribution or decay. Belgian historical cities are showcases of natural stones, even if these are not dominating the cityscape. Because of its durability, natural stone is a conservative construction element reflecting the building history, hence can be used as a proxy for age, style and renovation. In order to assess the architectural impact of natural stone use on the street view, a systematic inventory of natural stone occurrence, including the vernacular, has been made for the historical city centre of Leuven. This city centre has been built up throughout the 19th and 20th centuries, without a clear dominance of styles or materials. Qualitative properties, such as stone identification, its constructive or deco- rative use, age and style of the building were coupled with a GIS database of the buildings of the city of Leuven. This allows to link natural stone use to the progressive urbanisation and to highlight cases of neglect or in need of more suited conservation strategies.
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5de Vlaams-Nederlandse Natuursteendag 15-16.5.2014, Brussel Betekenisvol gebruik van natuursteen - Excursie natuursteengroeven langs de Maas 16.5.2014 Gidsboek
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5de Vlaams-Nederlandse Natuursteendag 15-16.5.2014, Brussel Betekenisvol gebruik van natuursteen - Excursie natuursteen Brussel
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Belgisch Marmer
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Petrografisch onderzoek van natuurstenen in knooppunt Schuman: Yellow Rock en Sunny Yellow
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Allozyme variation in two forest populations of Platynothrus peltifer (Acari, Oribatida)
- Samples of tritonymph individuals of Platynothrus peltifer were collected from two forest populations showing clear ecological and temporal divergences, and subjected to electrophoretic analysis of three enzymes, superoxide-dismutase, malate-dehydrogenase and esterases. Electrophoretic patterns were quite similar in both populations. This suggests that, after more than 40 generations, heterochronic differentiations do not seem to be related to allozyme alterations. Yet, a study of clonal diversity and its temporal modifications in both populations is required to confirm this hypothesis. © 1990.
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Horizontal and vertical distribution of Dolichopodidae (Diptera) in a woodland ecosystem
- Analysis revealed four distinct species groups, which also proved to be clearly different on a broader ecological basis. The horizontal distributions in many species could be explained by different environmental conditions. Although nearly all species were unequally distributed over the traps, their stratification patterns generally showed no significant correlation with recorded biotic and abiotic features. The observed vertical distributions may therefore be results of a combination of specific and environmental characteristics. -from Authors
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Temperature dependence of the Mössbauer parameters of the Fe-Ni phases in the Santa Catharina meteorite
- The temperature variation in the range 8-760K of the hyperfine parameters of the Fe-Ni phases in the Santa Catharina meteorite has been determined. It is suggested that the disordered 50-50 Fe-Ni phase actually consists of two distinct fractions, i.e. a completely disordered phase and one with intermediate long-range ordering parameter. The single-line subspectrum of the 28\%-Ni phase was found to display magnetic ordering below approximately 25K. © 1992 J.C. Baltzer A.G., Scientific Publishing Company.
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Cladistic Analysis of Metazoan Relationships: A Reappraisal
- Abstract-A recently published cladistic analysis of metazoan relationships based on 77 embryological and morphological characters is shown to be defective with respect to both methodological issues and the interpretation of certain characters. Consequently, many conclusions of this analysis are not supported by the data. Alternative phylogenetic hypotheses are therefore proposed, based on a re-evaluation of an adapted data set. © 1993 The Willi Hennig Society.
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Rediscovery of Astenocypris papyracea (Sars, 1903) (Crustacea, Ostracoda) in Kerala, India
- Astenocypris papyracea (Sars, 1903) has been found in paddyfields in Kerala, India. This is the first rediscovery of this enigmatic species since its original description from an unknown locality in Sumatra, almost 90 years ago. Astenocypris (the new name for Leptocypris) is a monospecific genus and, as the original description was incomplete, its exact taxonomic position has long been uncertain. Relying on the present redescription, we can confirm its allocation to the subfamily Cypricercinae, although a number of features hint at a relationship with the Isocypridinae. © 1993 The Linnean Society of London.
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Morphological and ecological characterization of Hercostomus (Hercostomus) plagiatus and a sibling species, H. verbekei sp.n. (Diptera: Dolichopodidae)
- Although two forms of Hercostomus plagiatus are separated in identification keys, both were considered to belong to one single species. My investigations, however, revealed that two distinct species were included. In this respect, H. plagiatus is redescribed, whereas H. verbekei sp.n. is described as new. Both species occur mainly in central and southern Europe; H. plagiatus is more common than its congener at nearly all sites investigated. Aspects of macro- and microhabitat preference, phenology and sex ratios in H. plagiatus are discussed. It is suggested that these two species are closely related. © 1993.
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Microtektite-like impact glass associated with the Frasnian-Famennian boundary mass extinction
- Glass spherules of probable impact origin occur in the Late Devonian Hony section in Belgium. They are found at the stratigraphic level of the Frasnian-Famennian boundary, which is marked by one of the largest mass extinctions in the Phanerozoic. The Hony glass spherules are chemically identical to those previously described from the stratigraphically equivalent Senzeille section located 90 km to the west-southwest. In contrast to the Senzeille layer, the age of the Hony spherule layer is well constrained by conodont biostratigraphy. The spherules have morphological and chemical characteristics similar to tektites and microtektites. They have a broad range of chemical composition with generally high [ K2O Na2O] and [ Al2O3 (Na2O + K2O)]. Their water content is in the range measured for tektites and impact glasses. Small inclusions of lechatelierite may be present in the spherules. These glass spherules are likely to be the product of an impact event that occurred at or very near the Frasnian-Famennian boundary. The target rock was probably a clay-rich pelitic sediment intermixed with carbonates. The 368 ± 1 Ma Siljan Ring crater (Sweden) is the most likely impact-site candidate. The Hony and Senzeille glass spherules represent the first substantial evidence that an impact event may be linked to the Frasnian-Famennian mass extinction. © 1994.
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Mesocyclops thermocyclopoides species-group: redefinition and content
- Within the genus Mesocyclops the thermocyclopoides species-group is defined on the basis of the presence of spiniform armature on the maxillar coxa. Examination of nineteen, mainly Palaeotropical species of Mesocyclops and nine representatives of the closely related genus Thermocyclops revealed, that the coxal part of the maxillar syncoxa of the species recently unified in the thermocyclopoides group is adorned with distinct rows of big spinules on its frontal surface. This character, with only one known exception in South Indian M. cf. papuensis, is absent in other species of Mesocyclops and all the Thermocyclops studied here. These species have no spinules on the maxillar coxa at all or very tiny scattered ones. © 1994 Kluwer Academic Publishers.
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Depth distribution of oligochaetes in Lake Baikal (Siberia - Russia)
- In the course of a preliminary sampling program, oligochaetes were collected along two transects in soft sediments in Lake Baikal. The number of oligochaetes present in the samples was counted, without distinguishing between species. The results suggest an exponential decrease in number of individuals (N) relative to depth (11,165 N m-2 at 21 m, 265 N m-2 at 1200 m). Most oligochaetes were found in the top 7 cm of sediment. The orange colour of the sediments suggests a high oxygen availability, even at the greatest water depths.
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Random amplified polymorphic DNA (RAPD) and parsimony methods
- Random amplified polymorphic DNA (RAPD) data possess a number of undesirable features for parsimony analysis. These features include their non-codominant inheritance, their anonymous nature, their different (a)symmetrical transformation probabilities, and their possible GC priming bias. As a consequence, no single parsimony method seems appropriate for RAPD data. Moreover, the presence/absence coding of RAPDs is equivalent to the invalid independent allele model for allozymes. These issues are discussed and the way in which parsimony analysis of RAPDs can be misleading is illustrated. © 1995.
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A new branchipodid genus and species (Crustacea: Branchiopoda: Anostraca) from South Africa
- Rhinobranchipus martensigen. et sp. nov.(Anostraca: Branchipodidae) was collected from a shallow temporary pool in the surroundings of Grahamstown (Cape Province, South Africa) (33ring operator18′S, 26ring operator32′E).Rhinobranchipusshares partial fusion of the chitinized basal parts of the male antennae, the so-called clypeus, with other Branchipodidae. The new genus is distinguished from confamilial genera by the morphology of the basal part of the penes. The new species, known from its type locality only, should be considered endangered, if it has not already become extinct as a result of recent modifications of its habitat. © 1995 The Linnean Society of London.
